A M E R I C A N CREOSOTE S I T E , W I N N F I E L D , L O U I S I A N AE C O L O G I C A L R I S K A S S E S S M E N TS I T E D E S C R I P T I O NThe American Creosote S i t e encompasses approx imat e ly 32 acres inthe town of W i n n f i e l d , Winn Parish, Louisiana. The site is in arural s e t t ing and is situated in a marshy area approx imat e ly one-h a l f mile southeast o f W i n n f i e l d ( F i g u r e 1). It i s immediatelya d j a c e n t to the Creosote Branch of the Drugdemon River and isr e l a t i v e ly f l a t with a total r e l i e f of 19 f e e t . Drainage f r om thesite is to the north and is enhanced by the presence of severaldi t che s . îIt would be inaccurate to describe the site in terms of d i s c r e t e ly \ci d e n t i f i a b l e habitat type s due to its h i g h l y dis turbed nature. ^However, two r e l a t i v e l y di s t inct areas make up most of the site.The f i r s t consis t s of areas f o r m e r l y used for untreated woodstorage, wood treatment, and treated wood storage. T h i s area ccomprises most of the s i t e , and is located in the south and central CD-p o r t i o n s o f the proper ty .The second consists of a r e la t ive ly undisturbed wet land-uplandcomplex . T h i s area is located along the east and west p er ipher i e sof the site and the northern third of the proper ty . The eastern,northern, and western site p er ipher i e s are f o r e s t e d and are thef o c u s o f this inve s t igat ion.Most of the site has h i s t o r i c a l l y been u t i l i z e d for various woodt r ea t ing ac t iv i t i e s and consequently is denuded of most vege tat ion.T h i s is p a r t i c u l a r l y true of the north-central por t ion of the s i tewhere various b u i l d i n g s , wood t r ea t ing a p p a r a t u s , and storage tankswere l o ca t ed . T h e s e structures have been broken down and p i l e s ofscrap material is stored p r e s e n t l y in p i l e s along the southeasternedge of the f o r e s t . T h i s ac t iv i ty has re sul ted in a h i g h l ydi s turbed vege tat ion and bare soil mosaic composed of a variety ofdi s turbance spec i e s , with l i t t l e d i s c ern ib l e pa t t ern. W e t l a n d treespec ie s such as b lack w i l l o w were observed growing a l o n g s i d e u p l a n dspecies such as black locus t , with escaped cultivars inc ludingscattered c r a b a p p l e (Pyrus s p . ) trees. Patches of grasses , such asquackgrass ( A a r o p y r o n r e p e n s ) , and cheatgrass (Bromus s e c a u l i n u s )were common throughout. Most of this area is covered by weedyherbaceous spec i e s , such as ragweed ( ^ b r p s j a a r t e m i s i f o l i a ) ,go ldenrod ( S o l i d a a o s p . ) , panic-grass ( P a n i c m f n j t i d u m ) . I n d i alovegrass (Eraaro s t i s p i l o s a ) , and numerous other invaders. Itthus o f f e r s l i t t l e habitat value f o r w i l d l i f e .H i s t o r i c documentat ion indicate s that the west-central and southernpor t i on of the site was used for "white" wood storage. The term"white" r e f e r s to untreated lumber delivered to a wood treatingf a c i l i t y and is derived f r o m the l i g h t color of thi s material incontrast to the darkened color of treated lumber. T h i s area hasbeen sub j e c t to le s s frequent and vigorous disturbance and is

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pre s en t ly in an early successional stage dominated by knee-highs a p l i n g s of red maple and wi l l ow ( S a l j . x s p . ) and shrubs such asalder ( A l n u s serrulatal and elderberry. Rushs, sedges, rough-stemmed goldenrod ( S o l i d a a o ruaosal , tick-seed sunf l ower f B i d e n sa r i s t o s a ) , pokeberry (Phvto lac ca ^•y^.qan^), and a variety of otherweedy herbaceous species are present.A r e la t i v e ly undisturbed we t land-upland complex is located alongthe east and west per ipherie s of the site and the northern third ofthe proper ty. Three r e la t iv e ly intact wetland types exist withinthis undisturbed area inc luding a pa lu s t r in e f o r e s t e d we t land , ap a l u s t r i n e emergent we t land, and an open water we t land.C o l l e c t i v e l y , these we t lands comprise most of the northern f o r e s t e darea.A p a l u s t r i n e f o r e s t e d wetland covers much of the northern port ionof the site. From the northwestern corner of the s i t e , it extendseastward along the Creosote Branch over much of the northernpor t i on of the site as well as the a d j a c e n t northern and easternparc e l s b e f o r e ev en tua l ly converging o f f - s i t e with parce l s whichare a d j a c e n t to a sewage d i s p o s a l p l a n t .T h i s community consists of a canopy dominated by several oaksin c lud ing w i l l o w oak (Quercus p h e l l o s ) , overcup oak (Q. l y r a t a ) andwater oak (0. n i cr er), American elm ( U l m u s americana) , and sweet gum(Liquidambar s t y r a c i f l u a ) . Sweetbay magno l ia , ( M a g n o l i av i r g i n i a n a ) , red mapl e (Acer rubrum), and black gum ( N y s s as y l v a t i c a ) represented a minor propor t i on of the canopy trees.U n d e r s t o r y vegetat ion consists of green ash ( F r a x i n u sp e n n s y I v a n i c a ) , water locust ( G l e d i t s i a a q u a t i c a ) , s t i f f dogwood(Cornus f o e m i n a ) , hybrid oak species (Q. f a l c a t a x Q. p h e l l o s ) andhornbean ( C a r p i n u s c a r o l i n i a n a ) . Due to seasonal f a c t o r s ,herbaceous vegetat ion was uncommon at the time of the study butgreenbrier ( S m i l a x r o t u n d i f o l i a ) , poi son ivy (Rhus r a d i c a n s ) , ands u p p l e j a c k (Berchemia s candens) were present. W h i t e oak (Q. a l b a )swamp chestnut oak (Q. m i c h a u x i i ) , American beech ( F a g u sg r a n d i f o l i a ) , l o b l o l l y pine ( P i n u s t a e d a ) , a n d black g u m ( N y s s as y l v a t i c a ) were noted in areas of s l i g h t l y higher ground.S m a l l pocke t s of emergent we t land s were noted in di s turbed por t i on sof the p a l u s t r i n e f o r e s t e d we t land. T h e s e areas exist a long thewestern and northern site boundary and have formed in canopyopenings and hi s tor ic road beds. T h e s e we t land s are dominated byswamp leucothoe (Leuco thoe racemosa), sweet p e p p e r b u s h ( C l e t h r aa l n i f o l i a ) , e lderberry f g f l i . b u . c u s c a n a d e n s i s ) , arrowleaf tearthumb( P o l y g o n u m s a g i t t a t u m ) , rush ( J u n c u s s p . ) , sedge (Carex s p . ) , a n din some areas by c a t t a i l s ( T y p h a l a t i f o l i a ) and other emergents.A open water wet land is present a long the east central corner ofthe site. It is s i tuated in an upland area dominated by s h o r t l e a fpine (P. e c h i n a t a ) , sweet gum, white ash ( F r a x i n u s amer i cana),mockernut hickory (Carya t omen to sa) southern red oak (Q. f a l c a t a ) ,and others. As suggested by the shape and size of the basin, it isl i k e l y that this pond is man-induced and may have been the s i te of

a former borrow pit or lagoon.Numerous small upland inclusions were i d e n t i f i e d within thenorthern f o r e s t ed wetland and are associated with railroad trackbeds and dredge spo i l s along the northern edge of the property.Thes e areas are higher in elevation than the surrounding f o r e s t ,and are dominated by white oak, sas safras ( S a s s a f r a s alfrifluffi),white ash, l o b l o l l y pine, and red maple s a p l i n g s . N a y a p p l e( P o d o p h y l i l v m p g l t a t U B ) and trumpet honeysuckle f L o n i c e r asempervirens) were present in the herbaceous layer.Most of the eastern f r i n g e s of the property as well as the parcelsa d j a c e n t to the sewage treatment p lan t consist of a uplandcommunity dominated by l o b l o l l y pine, short l eaf pine, Americanbeech and white oak. The understory is comprised of a variety ofs a p l i n g and shrub specie s , inc lud ing scrub oak (Q. i l i c i f o l i a ) . ^black locust (Robinia p s e u d o a c a c i a ) , black cherry (Prunus \Cs e r o t i n a ) , s a s s a f r a s , p r i c k l y dewberry (Rubus f l a g e l l a r i s ) , winged

acting through the C h i e f of Engineers, is authorized to issuepermits for the discharge of dredged or f i l l materials into watersof the Uni t ed S t a t e s , inc luding we t land s , with program oversight bythe EPA. The EPA has the authority to make f i n a l determinations onthe extent of Clean Water Act j ur i sd i c t i on . The COE also issuespermits for f i l l i n g , dredging, and other construction activities incertain wetlands under Section 10. Under authority of the F i s h andW i l d l i f e Coordination A c t , the FWS and the N a t i o n a l MarineFisher i e s Service review app l i ca t i on s for these Federal permits andprovide comments to the COE on the environmental impacts ofproposed work. In a d d i t i o n , the FWS is conducting an inventory ofthe N a t i o n ' s we t lands and i s producing a series of N a t i o n a l W e t l a n dInventory (NWI) maps f or the entire country. W h i l e the SCS hasbeen involved in wetland i d e n t i f i c a t i o n since 1956, it has recently rbecome more involved in wetland determinations through the"Swampbuster" provisions of the Food Securi ty Act of 1985. \CIn response to concerns that the Federal government e s tabl i sh a *^u n i f i e d approach to the i d e n t i f i c a t i o n and d e l i n e a t i o n of w e t l a n d s , Cthe E P A , the COE, the FWS, and the SCS reached agreement on the ^technical criteria for i d e n t i f y i n g and d e l i n e a t i n g we t lands andagreed to merge e x i s t ing methods into a s ingle u n i f i e d manual. OnJanuary 10, 1989 a s i n g l e manual was adop t ed as the recommendedmethodo l ogy f o r i d e n t i f y i n g a n d d e l i n e a t i n g we t land s .M E T H O D O L O G YI n i t i a l f i e l d reconnaissance of this site was made on the a f t e r n o o nof March 17, 1992. To gain a better understanding of sitecondi t i on s , th e f o l l o w i n g resources were consul t ed: U . S . G e o l o g i c a lSurvey ( U S G S ) t o p o g r a p h i c maps ( W i n n f i e l d East a n d W i n n f i e l d Westq u a d r a n g l e s ) , t h e S C S p r e p u b l i s h e d S o i l Survey o f W i n n Parish ( U . S .D e p t . o f A g . ) , t h e F W S N W I m a p ( W i n n f i e l d q u a d r a n g l e ) , t h e U S G SF l o o d Prone Area map, and aerial photo s obtained f r o m EPA Region 6.A f i e l d invest igation of the American Creosote S i t e and a d j a c e n tp r o p e r t i e s was conducted on March 18, 1992. W e t l a n d s werei d e n t i f i e d using the three parameter approach of the 1989 Federa lManual f o r I d e n t i f y i n g a n d D e l i n e a t i n g J u r i s d i c t i o n a l W e t l a n d s( F e d . Interagency Comm. f o r W e t l a n d Del inea t ion 1 9 8 9 ) . T h i sapproach i d e n t i f i e s w e t l and s based on the presence of the f o l l o w i n gcriteria: (1) a per iod i c predominance o f hydrophy t i c v ege ta t i on ,(2) a substrate o f p r e d o m i n a n t l y undrained hydric soil and (3) asubstrate saturated or inundated during at least part of thegrowing season.During this inve s t igat ion, data were co l l e c t ed on vegetat ion, so i l sand h y d r o l o g i c a l characteri s t i c s of the site. A q u a l i t a t i v eassessment was made of vegetative communities on-site by noting thed i s t r i b u t i o n and extent of d i f f e r e n t p l a n t spec ie s in each of threegeneral vegetative strata: the canopy, the unders tory, and theherbaceous layer. The extent of each species was e s t imated bydirect observation. The FWS has assigned a wet land indicatorc l a s s i f i c a t i o n (Reed 1 9 8 6 ) to p l a n t spec i e s , based on the growth

requirements of each species. T h i s was used concurrently withf i e l d observations to determine the approximate extent of wetlandplant communities on site.S o i l was evaluated to determine the upper l imit of the wetlandboundary. The number of sample s evaluated is u sual ly a func t i on ofthe size and variabil i ty of the site. However, in this study, soils a m p l i n g was relied upon to a lesser extent, given the h igh lydisturbed and contaminated nature of on- and po t en t ia l ly o f f - s i t esoil. S o i l was sampled using both screw and tube augers. S o i lp r o f i l e s were investigated vi sual ly for color, organic content,general texture, m o t t l i n g or streaking and evidence of pastdisturbance. A Munsell (Munse l l Color 1975) color chart was usedto q u a l i f y and record soil color. In general, so i l s are consideredhydric if the chroma at the top of the B horizon is "I" or l e s s , or °if mo t t l ing is present and the chroma is "2" or less. Low chroma *£(a dark or grayish c o l o r) along with the presence of m o t t l i n g , is \ca strong indicator of the reducing conditions present in saturated

(Licpi idambar s t y r a c i f l u a F A C W ) . Sweetbay magnolia, f M a g n o l i avirginiana O B L ) , red maple (Acer rubrum Facul ta t ive (FAC)), andblack gum ( N y s s a sylvatica FAC) represented a minor proportion ofthe canopy trees. Understory vegetation consists of green ash(Fraxinus pennsylvanica FACW), water locust ( G l e d i t s i a aquaticaO B L ) , s t i f f dogwood (Cornus foemina FACW), hybrid oak species (Q.f a l c a t a x Q. phe l l o s FACW) and hornbean (Carpinus caroliniana FAC).Due to seasonal fac t or s , herbaceous vegetation was uncommon at thetime of the study but greenbrier ( S m i l a x r o t u n d i f o l i a FAC), poisonivy (Rhus radicans Not C l a s s i f i e d (NC)), and s u p p l e j a c k (Berchemiascandens FACW) were present. Whi t e oak (Q. alba Facul ta t ive U p l a n d(FACU)) swamp chestnut oak (Q. michauxii FACW), American beech( F a g u s a r a n d i f o l i a F A C ) , l o b l o l l y pine (Pinus taeda F A C ) , a n d blackgum ( N y s s a sylvatica FACW) were noted in areas of s l i g h t l y higherground.S m a l l pockets of emergent wetlands were noted in disturbed portionsof the palustrine forested wetland. These areas exist along thewestern and northern site boundary and have formed in canopyopenings and historic road beds. These wetlands are dominated byswamp leucothoe (Leucothoe racemosa FACW), sweet pepperbush(Cle thra a l n i f o l i a F A C W ) , elderberry (Sambucus canadensis F A C W ) ,arrowleaf tearthumb (Polyaonum s a g i t t a f o ™ O B L ) , rush (Juncu s sp.FACW), sedge (Carex sp. FACW), and in some areas by ca t ta i l s ( T y p h al a t i f o l i a OBL) and other emergents.An open-water wetland is present along the east central corner ofthe site. It is situated in an upland area dominated by short l eafpine (P. echinata FACU), sweet gum, white ash (Fraxinus americanaFACU), mockerhut hickory (Carva tomentosa FAC) southern red oak (Q.f a l c a t a FACU) , and others. As suggested by the shape and size ofthe basin, it is l i k e l y that this pond is man-induced.In the west central portion of the site, abandonment has occurredin recent times. H i s t o r i c documentation indicates that this areawas used for "white" wood storage. The term "white" re f er s tountreated lumber delivered to a wood treating f a c i l i t y and isderived from the l ight color of this material in contrast to thedarkened color of treated lumber. Most of this area is in an earlysuccessional stage and is dominated by knee-high sapl ings of redmaple and wi l low ( S a l i x sp. FACW) and shrubs such as alder ( A l n u sserrulata OBL) and elderberry. Rushs, sedges, rough-stemmedgoldenrod ( S o l i d a g o rugosa F A C ) , tick-seed sunf lower (Bidensaristosa FACW) , pokeberry (Phyto lacca americana FACU) and a varietyof other weedy herbaceous species are present.Numerous small upland inclusions were i d e n t i f i e d within thenorthern fore s t ed wetland and are associated with railroad trackbeds and dredge s p o i l s along the northern edge of the property.These areas are higher in elevation than the surrounding f o r e s t ,and are dominated by white oak, sassafras ( S a s s a f r a s albidum FACU),white ash, l o b l o l l y pine, and red maple sap l ing s . M a y a p p l e( P o d o p h y l l u m p e l ta tum FACU) and trumpet honeysuckle (Lonicerasempervirens FACU) were present in the herbaceous layer.

Most of the eastern fr inge s of the property as well as the parcelsa d j a c e n t to the sewage treatment p lan t consist of a uplandcommunity dominated by l o b l o l l y pine, shor t l ea f p ine, Americanbeech and white oak. The understory is comprised of a variety ofs a p l i n g and shrub species, inc luding scrub oak fQ. i l i c i f o l i aF A C U ) , black locust fRobin ia pseudoacacia F A C U ) , black cherryf P r u n u s serotina F A C U ) , s a s s a f r a s , p r i c k l y dewberry fRubusf l a a e l l a r i s F A C U ) , winged sumac f R h u s cooal l ina F A C U ) , a n ddangleberry (Gaylu s sa c ia f rondo sa F A C ) . T y p i c a l herbaceous speciesinclude bracken f e rn f P t e r i ^ J " i f lgu. i l inu.BI FACU), and goldenrod( S o l i d a g o rugosa F A C , a n d S . g r a m i n i f o l i a F A C ) .The site i t s e l f is p r e s en t ly a h igh ly disturbed vegetation and baresoil mosaic composed of a variety of disturbance species, withl i t t l e d i s c ernible pat tern. W e t l a n d tree species such as blackw i l l o w were observed along the eastern periphery growing alongs ideupland species such as black locus t , with escaped cult ivarsi n c l u d i n g c rabapp l e (Pyrus s p . N C ) trees scattered throughout.Patches of grasses, such as quackgrass (Agropyron repens FACU), andcheatgrass (Bromus secaulinus NC) were common throughout. Most ofthe actual site is covered by weedy herbaceous species, such asragweed ^A^brosia a r t e m i s i f o l i a F A C U ) , goldenrod ( S o l i d a g o s p . N C ) ,panic-grass f P a n i c u m ni t idum N C ) , I n d i a lovegrass (Eraoro s t i sp i l o s a FACU), and numerous other invaders. It thus o f f e r s l i t t l ehabitat value f o r w i l d l i f e .S o i l sThe SCS prepub l i shed S o i l Survey for Winn Parish shows soil typesmapped on the site and a d j a c e n t parcel ( F i g u r e 2). T h e s e inc ludethe Guyton, F r i z z e l l , Savannah, and Sacul mapping units. The s em a p p i n g units are part of a geographical association that grades(bo th e l e v a t i o n a l l y and h y d r o l o g i c a l l y ) f r om the l o w l a n d , p o o r l ydrained and f l o o d e d Guyton unit, to the u p l a n d , well drained Saculunit.In the v i c in i ty of the s i t e , the Guyton and F r i z z e l l m a p p i n g unitsare f ound a long a l a n d s c a p e catena that is associated with thehistoric Creosote Branch f l o o d p l a i n . A soil catena is a sequenceof s o i l s derived f rom the same parent material and occurring unders imi lar c l imat i c condit ions, but having d i f f e r e n t characteristicsdue to variation in r e l i e f and drainage. Both s o i l s are derivedf r o m a l l u v i a l sediment and are f ound on terraces of P l e i s t o c e n eage. The Guyton mapping unit is c l a s s i f i e d by the SCS as hydric.H y d r i c s o i l s have been d e f i n e d by the SCS as soil that is either(1) saturated at or near the soil sur fac e with water that isv i r t u a l l y la ck ing f r e e oxygen f or s i g n i f i c a n t p er iod s during th egrowing season, o r ( 2 ) f l o o d e d f r e q u e n t l y f o r long p er i od s duringthe growing season. T h i s d e f i n i t i o n i d e n t i f i e s so i l s that supportthe growth of h y d r o p h y t e s or wet land vegetat ion. The Guytonm a p p i n g unit consists of very d e e p , p o o r l y drained and very p o o r l ydra ined , s l o w l y permeable s o i l s formed in thick loamy sediment.T h i s m a p p i n g unit is present in a narrow band immed ia t e ly a d j a c e n tto both banks of the Creosote Branch and an unnamed tributary that

drains parce l s to the west.The F r i z z e l l mapp ing unit is present immediate ly ad ja c en t to theGuyton unit and at a s l i g h t l y higher elevation in the landscape.It consists of deep, somewhat poorly drained, s lowly permeablesoi l s . Much of the h igh ly disturbed central portion of the site,as well as portions of the northern and western site peripherie sare mapped as F r i z z e l l soils. A l t h o u g h this mapping unit is notc l a s s i f i e d as a hydric s o i l , it can contain hydric inclusions ofgeographica l ly related soils (Pers. comm. with B. Touchet 1992)•The Savannah and Sacul mapping units are part of a second soilcatena found on terraces and upland areas. The s e so i l s are derivedf r o m f l u v i a l and marine d epo s i t s and are present in higher elevated Tareas in the landscape than the G u y t o n - F r i z z e l l catena. The j-Savannah and Sacul s o i l s are described by the SCS as moderate ly ^well dra ined , s l o w l y to moderate ly s l ow ly permeable soi l s . A m a j o r .d i s t i n g u i s h i n g characteris t ic is that the former has a f r a g i p a n (animpermeable sub sur face l a y e r ) whereas the l a t t e r does not. T h i s ^re la t iv e ly impervious layer could account for the high water table €S>observed in some p l a c e s in the western portion of the site. Muchof the western site p er iphery and o f f - s i t e areas have been mappedas Savannah so i l s .Due to the p o t e n t i a l l y contaminated nature of soi l s on and ad jac en tto the s i t e , p a r t i c u l a r l y in the immediate vic ini ty of the woodtreat ing area, vegetat ion and hydro logi ca l characteri s t ic s wererel ied upon to a greater extent than soil in de t ermining thewet land l i m i t s . For instance, v i s i b l e evidence of soilcontamination along the edge of the wood treatment area in thenorthern and western port ions of the s i te provided s u f f i c i e n tj u s t i f i c a t i o n to avoid intrusive soil s a m p l i n g a c t iv i t i e s .S i m i l a r l y , the s o i l s in some areas have been p h y s i c a l l y di s turbedby d r e d g i n g , f i l l , and construction of road and rail beds to theextent that soil characterization lends l i t t l e insight into wetlandh y d r o l o g y .S o i l s a m p l i n g and eva lua t i on , while l i m i t e d in s cope, g e n e r a l l yc o n f i r m e d the extent of mapped so i l s . However, the presence ofhydric conditions within the Guyton mapping unit were not asextensive as m a p p e d , m o s t l y due to the extensive dis turbanceassociated with the site. S o i l examined immedia t e ly a d j a c e n t tothe Creosote Branch, drainage d i t ch e s , road and rail beds werer e f l e c t i v e of dredge and f i l l , as well as construction ac t iv i t i e s .In these areas, f i e l d examination showed a h i g h l y disturbed p r o f i l ec on s i s t ing of a l t e r n a t i n g layers of organic material and highchroma sand, making it d i f f i c u l t to draw in f e r enc e s regarding theextent of seasonal saturation. However, the presence of s u r f a c eh y d r o l o g i c indicator s and f a c u l t a t i v e wet land vege tat ion spec ie swas s u f f i c i e n t evidence to c l a s s i f y much of this area as f r e shwat erwetland using the current F e d e r a l me thodo l ogy . At d i s tance sprogr e s s i v e ly d i s tant f r o m these dis turbed areas, the soil c l o s e l yr e f l e c t e d t h e t y p i c a l pedon (charac t er i s t i c p r o f i l e ) f o r thi sm a p p i n g unit. When compared to the Munse l l color chart, the chroma

of these so i l s was g enera l ly in the 10YR 2/1 to 10YR 4/2 range,with common and distinct mot t l e s , and was strongly indicative ofhydric conditions. At the time of the s tudy, much of the acreagewas f l o o d e d and soil was saturated to the surface.The m a p p i n g per formed by the SCS is based on aerial pho tography ata scale of 1:20,000. T h i s prohibi t s the mapping of small hydricinclusions located in depres s ions and swales within largernon-hydric mapping units. As discussed previously, the F r i z z e l lm a p p i n g unit is poor ly drained, low in the landscape and l i k e l y tocontain hydric inclusions. F i e l d inves t igat ion confirmed thepresence of extensive areas of hydric soil within F r i z z e l l unit.T h e s e inclusions are situated within depres s ional and diked areasalong the northern per iphery of the site and the Creosote Branchf l o o d p l a i n . T h e s e inclusions were in the 10YR 5/1 to 10YR 3/2range with dist inct mottles . Many of these areas were f l o o d e d andground water was present at the soil sur face . Much of thepa lu s t r in e f o r e s t e d wetland i d e n t i f i e d on-and o f f - s i t e i sassociated with the area mapped as F r i z z e l l so i l .The east central port ion of the s i te, which has h i s t o r i c a l l y beenu t i l i z e d as "white" wood storage area, has a p p a r e n t l y been gradedand f i l l e d to accommodate log stacking racks. As discussedp r e v i o u s l y , soil examination showed a h i g h l y di s turbed p r o f i l econs i s t ing of a l t e r n a t i n g layers of f i l l and natural soil mater ial .The natural soil components ranged f r o m 10YR 5/1 to 10YR 7/4 withcommon m o t t l e s , and was indicat ive of hydric condi t ions .A d d i t i o n a l l y , the soil in most of this area was saturated to thes u r f a c e and f a c u l t a t i v e wet land vegetat ion was present p r o v i d i n gs u f f i c i e n t evidence to c l a s s i f y much of this area as f r e shwaterwet land using the current F e d e r a l me thodo l ogy .H y d r o l o g yT h e U S G S topograph i c survey map, a n d t h e F W S N W I m a p ( F i g u r e 3 ) ,and site aerial p h o t o g r a p h s indicate that the site drainspr edominant ly in a northerly direction into the Creosote Branch.F u r t h e r , the f o r e s t e d and emergent we t l and s in the northern por t i onof the site are g e n e r a l l y associated with its r iparian zone. Incontras t , the open water wetland a long the eastern site p er ipheryis h y d r a u l i c a l l y di scont inuous with the northern wetland c ompl ex .The p r i n c i p a l h y d r o l o g i c f e a t u r e in the v i c in i ty of the s i te is theCreosote Branch, which forms the central core of the pa lu s tr inewetland hydrosys tem and the northern boundary of the site. TheUSGS f l o o d prone map prepared in 1957 indicate s that thi s reach ofthe Creosote Branch is not within a f l o o d prone area ( F i g u r e 4).As it pas s e s the s i t e , the river f l o w s through a rather s t e e p l y cutchannel a p p r o x i m a t e l y 15 f e e t in d e p t h , and 20 f e e t in width. Atthe time of the s t u d y , the river was f l o w i n g b r i s k ly in an ea s t er lyd ir e c t i on , and ranging in d e p t h f r o m a p p r o x i m a t e l y one to threef e e t . The banks of the river showed a thick under ly ing layer ofdarkened s o i l , a p p a r e n t l y contaminated with creosote, at a d e p t h ofabout six f e e t below the sur fac e . T h i s exposed and r e l a t i v e l y

erodible material may account for the sheen observed on the watersurface .S i t e hydrology has been p r o f o u n d l y influenced by past humanactivity. In the central portion of the site, several small man-altered or man-made tributaries and drainage di tches ( a p p r o x i m a t e l ytwo f e e t wide and one f o o t d e e p ) run perpendi cu lar to the CreosoteBranch, each f l o w i n g in a northerly direction. In addi t ion,several drainage d i t che s are present in the parcel north of theCreosote Branch which run p a r a l l e l to the railroad bed in awestward direction toward the proper ty corner, then carry surfacef l o w southward into the Creosote Branch at the northwestern cornerof the site. The s e d i t ch e s , while man-made, containeda p p r o x i m a t e l y 10 inches of water at the time of this s tudy and weref l o w i n g at a moderate rate. A series of ditches within uplandportions of the ad jac en t northeastern parcel drain surface f l o wwestward into the Creosote Branch.Based on historic land use on and ad jac en t to the s i te, it appearsthat the hydro l ogy of the area has been p a r t i a l l y al tered for sometime. N e v e r t h e l e s s , d i t che s constructed on the site and in thea d j a c e n t northern and northeastern parcel s appear to have hadl i t t l e long term e f f e c t s on the hydrology of the pa lu s t r inef o r e s t e d we t land. S o i l examination revealed saturation to thes u r f a c e in most l o ca t i on s , while extensive areas were observed tobe inundated. In locat ions where soil sampl ing was not undertaken,f a c u l t a t i v e wet land or o b l i g a t e wet land p l a n t s were commonlyobserved.A l t e r a t i o n s to surface hydrology have probably he lp ed to impairwet land f u n c t i o n s in other part s of the s i t e , such as in hi s toricwet land areas along the west central site p er iphery. T h e s e areashave also s u f f e r e d degradat ion f rom depo s i t i on o f f i l l mat er ia l ,construction ac t iv i t i e s , and erosion from the site, as well asinvasion of d i s turbance-adapt ed weedy p l a n t s . Evidence for th i s i sprovided by the d i s turbed soil p r o f i l e s , and the exi s tence of f i l lmaterial in soil sample s .Review of the p r e p u b l i s h e d SCS S o i l Survey o f W i n n Parish revealsthat the American Creosote S i t e is underlain p r e d o m i n a n t l y byGuyton and F r i z z e l l s o i l s , which f o r m e r l y drained d i r e c t l y into theCreosote Branch. D r e d g i n g , f i l l , and construction of road and railbeds , have undoub t ed ly a f f e c t e d the drainage p a t t e r n of thi s areaby i n f l u e n c i n g the rate and direction of stormwater r u n o f f f l o w i n ginto the river. It appears that much of the drainage f l o w whichwould have normal ly t r a v e l l e d d i r e c t l y into the river may have beendiverted to d i t c h e s , and in some cases has become t r a p p e dupgradient of f i l l - a s s o c i a t e d dredging and construction act ivi t ie s .Consequent ly , some wet land boundaries i d e n t i f i e d in the f i e l dt ended to f o l l o w the edge of man-made structures.S i t e hydro logy may have also been fur ther in f lu enc ed by pastac t iv i ty in the eastern por t i on of the s i t e , where a borrow p i t ,d i s p o s a l lagoon or other ac t iv i t i e s may have induced the

development of a shallow pond. The source of water in this pondappears to be surface r u n o f f , and this may be augmented by seasonalhigh water levels. Because of the time of year this study wasconducted, this could not be documented. T h i s pond does notpresent ly support s i gn i f i can t amounts of hydrophytic vegetationalong the margin, and is surrounded by upland vegetation. It islocated in an area of the site appearing in the soil survey asSavannah m a p p i n g unit. Consequent ly, this area was i d e n t i f i e d asopen water. T h i s area, while appearing quite natural in itspresent s tate , may very well exist as a result of past act ivi t ie sthat obstructed or altered normal drainage pat terns . It appearsthat berms west and north of this pond may have he lped contain someof the drainage in this area.F o r e s t e d we t land s along the western proper ty boundary have beenseparated from adjacent wet lands to the north by the constructionof a dirt access road and several residences. T h i s area has becomedegraded as a result of its proximity to the site and constructionac t iv i t i e s , l eaving a narrow s t r i p of we t lands a long CreosoteBranch with somewhat decreased habitat value.Other f a c t o r s i n f l u e n c i n g present site hydrology include seepageand erosion f r o m the site i t s e l f . During this f i e l d inve s t iga t i on ,seepage was observed in the eastern upland area, as well as alongthe f l o o d p l a i n of the Creosote Branch, eventual ly dra in ing intothe watershed. Some of this f l o w begins well u p s l o p e of areasi d e n t i f i e d as f r e shwa t er wetland in thi s s tudy. At the time ofthi s s tudy, some of these seepage areas contained an o i l y sheenthat may be a consequence of past dumping ac t iv i t i e s .W E T L A N D D E T E R M I N A T I O NA l t h o u g h not indicated on the FWS NWI wetland map, port ions of theAmerican Creosote S i t e possess the three criteria necessary to meetthe regulatory d e f i n i t i o n of a wet land. Thes e are m a p p e d , based onf i e l d d e t e rmina t i on s , in F i g u r e 5. A p p r o x i m a t e l y 28.3 acres ofw e t l a n d , and 1.6 acres of open water were i d e n t i f i e d on the siteand a d j a c e n t par c e l s . Of these, a p p r o x i m a t e l y 13.9 acresc o l l e c t i v e l y are within the site boundary. These wet lands covermost of the northern por t ion of the s i t e , as well as the easternand western per ipherie s . The on-site wet lands converge in aneastern d ire c t i on with o f f - s i t e w e t l a n d s .W e t l a n d s present on and a d j a c e n t to the site have become degradedto some extent as a consequence of human activit ies . The term"degraded" as used here, f o l l o w s the meaning "a we t land in whichthere is impaired s u r f a c e water f l o w or groundwater h y d r o l o g y , orexcessive d r a i n a g e ; a wet land which has been p a r t i a l l y f i l l e d orexcavated, contaminated with hazardous substances, or which has ane co l og i ca l value s u b s t a n t i a l l y le s s than that of undi s turbedwe t land s in the region". N e v e r t h e l e s s , the we t l and s i d e n t i f i e d inthi s s tudy, while degraded f r o m erosion and contaminants , s t i l lo f f e r some habitat value, as evidenced by s i g h t i n g s o f w i l d l i f especies inc lud ing b irds , r e p t i l e s , and amphibians. Amphib ians are

t y p i c a l l y sensitive to changes in habitat characteristics,suppor t ing the premise that these wet lands are not severelydegraded. Further, these wetlands are of high quality from theperspect ive of f l o o d control, aqu i f er recharge and, in par t i cu lar ,sediment, nutrient, and contaminant t rapping. In contrast,wet lands in the western portion of the site are genera l ly h igh lydisturbed and degraded.C O N C L U S I O N S O N W E T L A N D D E T E R M I N A T I O N1) Palus tr ine f o r e s t e d we t land s , pa lu s t r ine emergent we t land s ,and open waters were i d e n t i f i e d on and adjacent to theAmerican Creosote S i t e and c o l l e c t i v e l y compriseapprox imat e ly 28.3 acres. A p p r o x i m a t e l y 13.9 acres ofwe t lands are present within the site boundary. ir

j*~2) Open waters present in the east central por t i on of the siteappear to be man-induced. 3̂"3) Although not f i e l d de l ineated ( i . e . , not f l a g g e d and Csurveyed), the approx imat e extent of on- and o f f - s i t e e>wet lands have been indicated on a site map.4) Most we t lands present on the site have been degraded to someextent. W h i l e the degree of degradat ion has been greatestin the western por t ion of the s i t e , we t land s of higherqua l i ty are present in northern port ions of the site. Thewetland present on the site and areas a d j a c e n t to the sites t i l l provide va luab l e habitat and are f u n c t i o n i n g asvaluab l e w e t l a n d s .5) It is our op in ion the remedial a c t iv i t i e s w i l l d i r e c t l y orind ir e c t ly fur ther degrade or necessitate the destruction ofwe t land s . If thi s is to occur, as we a n t i c i p a t e , s t ep sshould be taken to minimize the des truction and degradat ionof the w e t l a n d s .

T O X I C I T Y T E S T I N GSeveral rounds of t ox i c i ty tests have been conducted on site since1987. The sample s obtained at the site were not analyzed forcontaminant chemistry. The heterogenei ty of the site combined withthe remedial a c t iv i t i e s conducted on site by Region 6 have l i m i t e dthe a p p l i c a b i l i t y of the sample s to the present risk assessment.W h i l e soil and sediment sample s have been taken in c lose p r o x i m i t yto t o x i c i t y test sampl e s and water s a m p l e s have been analyzed f r o mthe creek at a p p r o x i m a t e l y the same t ime, correlations of chemistryto t o x i c i t y would p r o b a b l y be a misuse of the data. The value ofthe t o x i c i t y t e s t s conducted at the site should be in c o n f i r m i n gthat the s i te is or is not toxic to the test organisms. Thetox i c i ty tes t s conducted have shown that the site matrices aretoxic to the specie s tested ( A p p e n d i x 1).

Earthworm T o x i c i t y T e s t sThe EPA Environmental Research Laboratory-Corval l i s comple ted apre l iminary t ox i c i ty evaluation on soil sample s co l l e c t ed inFebruary, 1992 from the American Creosote site. Seven soil sampleswere te s ted using the earthworm bioassay.Locat ion AE-1 is a d j a c e n t to Creosote Branch a p p r o x i m a t e l y 300 f e e tupstream from the site. Locations AE-10, AE-11 and AE-12 are inthe former untreated wood storage area. Locations AE-14 and AE-15are in the former wood treatment area. Location AE-19 is in thewooded area to the north of Creosote Branch and in the formertreated wood storage area. Locations AE-10, AE-11, AE-12, AE-14,AE-15, AE-19 correspond to the f o l l o w i n g soil sample locations int h e Remedial I n v e s t i g a t i o n report S S - 1 0 , S S - 1 1 , S S - 1 2 , S S - 1 4 , S S - 1 5 ^and S S - 1 9 . r-

vCThe s ampl e s f r o m l o ca t i ons AE-1, AE-10, AE-11, and A E - 1 2 , as well ^as negative c on tro l , exhibi ted no m o r t a l i t y , whi le s a m p l e AE-19 c-exh ib i t ed a s i n g l e m o r t a l i t y out of 30 earthworms and s a m p l e s AE-14 _and AE-15 exhibited comple t e mor ta l i ty . ®Quali ta t ive observations are recorded to evaluate po t en t ia lsub l e tha l e f f e c t s . Earthworms exposed to soil s a m p l e AE-1 producedseveral earthworms with segmental cons tr ic t ions and le s ions.Earthworms exposed to s o i l s f r o m sample locat ion AE-10 appearedclumped together as a p o t e n t i a l avoidance mechanism. Earthwormsexposed to s o i l s f r o m s a m p l e l o ca t ions AE-11 and AE-12 exhibited nosub l e tha l e f f e c t s . Earthworms exposed to s a m p l e l o ca t ions AE-14and AE-15 exhibited comple t e mor ta l i ty . The s e soil sampl e s werev i s i b l y stained and o i l e d . S o i l s a m p l e s AE-14 and AE-15 a l soproduced q u a l i t a t i v e observations of decomposed earthworms on thes u r f a c e of the test containers. T h i s observation sugge s t s that theearthworms did not burrow or burrowed and returned to the s u r f a c e ,and thus may have been severely e f f e c t e d without soil inge s t i on andwith reduced dermal exposure. T h e s e observations, c o u p l e d withvisual observations of those par t i cu lar soil sample s ( d a r k , s l i m y ,o i l y ) c l e a r l y indi ca t e s soil t o x i c i t y . Several earthworms exposedto soil f r o m sampl e l o ca t i on AE-19 exhib i t ed segmentalcons tr i c t i on s and re s tr i c t ed movement.Aquat i c T o x i c i t y T e s t sChronic t o x i c i ty t e s t ing was conducted in February, 1992 onsediment e luat e and water s a m p l e s ( s i t e and r e f er ence s a m p l e s ) byEPA Region 6 H o u s t o n Laboratory using C e r i o d a p h n i a dubia andP i m e p h a l e s p rome la s ( f a t h e a d minnows) test organism. S t a t i o n A W 1is located a p p r o x i m a t e l y 300 f e e t ups tream of the site. S t a t i o nAW2 i s located a d j a c e n t to the f ormer treatment area. S t a t i o n A W 2 ais l ocated on a s ide tr ibutary of Creosote Branch not d i r e c t l ya f f e c t e d by the site. S t a t i o n AW3 is located downstream of thef o r m e r treatment area.A f t e r seven days , C e r i o d a p h n i a dubia organisms exposed to sediment

eluate f r om s tation # A W 2 a were s i g n i f i c a n t l y a f f e c t e d , based onnumber of young produced per f e m a l e , while no s igni f i cant e f f e c twas observed in organisms exposed to the eluates f rom S t a t i o n s AW1,AW2, and A W 3 . Dissolved oxygen remained >97% of saturation.Temperature was 25+1° C. A f t e r seven days , P i m e p h a l e s promelasorganisms exposed to sediment eluates f rom S t a t i o n s AW2, A W 2 a , andAW3 were s i g n i f i c a n t l y a f f e c t e d while no s i g n i f i c a n t e f f e c t wasobserved in organisms exposed to the S t a t i o n AW1 eluate.Dissoloved oxygen remained :>87% of saturation throughout theexposure. Tempera ture was maintained at 25+1° C. A f t e r seven daysof exposure for Cer iodaphnia dubia organisms to ambient water sites a m p l e s , there was no s i g n i f i c a n t e f f e c t , based on m o r t a l i t y orreproduction. Dissolved oxygen concentrations remained >86% ofsaturation throughout the exposure. Temperature was maintained at25+1° C. A f t e r seven days of exposure of P i m e p h a l e s prome la s toambient water site sample s , there was no s i g n i f i c a n t e f f e c t .Dissolved oxygen remained >85% of saturation throughout theexposures. T e m p e r a t u r e was maintained at 25+1° C.C H E M I C A L S OF C O N C E R NThe chemicals of concern were chosen based on the general chemicalcontaminants de t ec t ed on site. The main contaminant in all mediawas creosote. Creosote is g e n e r a l l y composed of 85 % p o l y a r o m a t i chydrocarbons (PAHs), 10 % p h e n o l s and 5 % heterocycl ic s . Otherchemicals detected at the site include pentach loropheno l (PCP) anddiox ins . Being that creosote is such a wide mixture of chemical sit would genera l ly be very d i f f i c u l t to e l i c i t which s p e c i f i cchemicals should be the chemicals of concern. F o r t u n a t e l y , thereare l i t e ra tur e values for both creosote and to ta l PAHs. Based onthi s i n f o r m a t i o n , and a lack of s p e c i f i c chemical ana ly s i s ofindigenous b i o ta , we w i l l be using the general chemical mixtures asthe chemicals of concern.A l i t erature search was conducted to f i n d doses of p h e n o l , PAH,d i o x i n and PCP reported to cause toxic e f f e c t s in aquaticorganisms, mammals and birds . S p e c i e s , dose and e f f e c t s of phenolare presented in T a b l e 1 of thi s document. S i m i l a r i n f o r m a t i o n forPAH, d iox in and PCP are presented in T a b l e s 2, 3 and 4,r e sp e c t i v e ly .Literature values for chronic t ox i c i ty could not be found forseveral spec i e s and compounds , however l e t h a l concentration of 50%m o r t a l i t y (LC^,. values were obtained. For purpo s e s of th i s riskasse s sment, a f a c t o r of 10 was used to convert an LC^ to a lowestobservable adverse e f f e c t level ( L O A E L ) . LOAELs c a l cu la t ed usingi n f o r m a t i o n in T a b l e s 1 to 4 are presented in T a b l e 5.All t ox i c i ty values located in the l i t e ra tur e search are presentedin the f o l l o w i n g summaries. Several numbers were not used in therisk c a l c u l a t i o n s based on ques t ionable methods or conclusions inthe s tudie s . When several t o x i c i ty values were a v a i l a b l e , the moreconservative values were used in the risk c a l c u l a t i o n s . T h i s wasdetermined to be a reasonable estimate of toxic contaminant l eve l s .

A summary of bioconcentration and t ox i c i ty in format i on obtainedduring the l i t erature search is presented below.P H E N O LPhenol is w ide ly used as a chemical intermediate and is f ound increosote. T h e r e f o r e , for the purposes of this risk assessment, thedetermination of the risk to biota f rom phenol w i l l be ca l cu la t ed .USEPA ( 1 9 8 0 ) s tates that phenol does not bioaccumulate a p p r e c i a b l yin aquatic organisms. Kobayash i et al. ( 1 9 7 6 ) ca l cu la t ed abioconcentration f a c t o r (BCF) of 1.2 - 2.3 to f i s h . T h e r e f o r e , abioconcentration f a c t o r w i l l not be used, except for f i s h , tocalculate the dose to biota. cr-A l g a e ^Reynolds et al. ( 1 9 7 5 ) found that exposure to 20,000 nq/1 of phenol "^for 2 days caused a reduction of cell numbers by 66%. Earl i er it cwas s tated that a f a c t o r of 10 would be used to convert an LD^ to €3an L O A E L . A f a c t o r of 15 w i l l be used to convert thi s LDM to anL O A E L . T h e r e f o r e , for the risk asses sment, a c a l c u l a t e d LOAEL of1333 A * g / l w i l l be used.F o r a g e f i s hK o b a y a s h i et al. ( 1 9 7 6 ) ca l cu la t ed a bioconcentration f a c t o r of 1.2- 2.3 to f i s h . For the purpos e s of this risk assessment, the BCFof 2.3 w i l l be used to c a l c u l a t e dose.Several s tudi e s have been conducted to determine the LC^ of phenolto f a t h e a d minnow ( P i c k e r i n g and H e n d e r s o n , 1966; Ruesink andS m i t h , 1 9 7 5 ) . V a l u e s ranged f r o m 24000 ng/l phenol for a 96 hrf l o w - t h r o u g h bioassay to 34 ,270 j ^ g / l for a 96 hr s ta t i c t e s t .G e i g e r et al. ( 1 9 8 4 ) conducted 96 hr bioassays on variouscomponents of creosote. T e s t s conducted on f a t h e a d minnows withphenol had an LC^ of 32.4 m g / 1 in the water column. A ca l cu la t edLOAEL of 3240 / i g / l i t e r w i l l be used in th i s risk assessment.Piscivorous f i s hCairns and Sche i e r ( 1 9 5 9 ) l i s t an LCg,, of phenol to blue g i l l of20,000 ng/I for a 96 hr s ta t i c bioassay and 11,500 M 9 / 1 for a 96 hrs ta t i c bioassay. A l s o , the Ambient H a t e r Q u a l i t y Cri t e r ia hasbeen e s t a b l i s h e d at 600 M 9 / 1 as a 24 hr average and should notexceed 3400 M g / 1 at any time (USEPA 1 9 8 0 ) . A ca l cu la t ed LOAEL of2000 / j g / l i t e r w i l l be used for purpos e s of thi s risk assessment.S m a l l MammalDeichmann and W i t h e r u p ( 1 9 4 4 ) f ound an oral dose to rats of LC^ of530 m g / k g pheno l . A value in Sax and Lewis ( 1 9 8 9 , Reference JPETAB8 0 , 2 3 3 , 4 4 0 ) , LC^0 oral dose to rabbits of 420 m g / k g . For thepurpose s of the risk ca l cu la t i on , a calculated LOAEL for rats of 53

m g / k g diet was converted to 4 mg/kg-day by a d j u s t i n g for bodyweight and ingest ion rate for a rat (NIOSH 1 9 8 2 ) .Red foxNo l i t erature values were located for toxic l eve l s of pheno l s tof o x e s . Sax and Lewis ( 1 9 8 9 ) cite a parenteral TDL O value for dogsof 651 m g / k g ; this value was assumed to be a LOAEL. For thepurpose s of this risk assessment, the 651 m g / k g diet was convertedto 16.3 m g / k g / d a y by a d j u s t i n g for body weight and inges t ion ratef o r a surrogate spec ie s , t h e d o g ( N I O S H , 1 9 8 2 ) .

P O L Y A R O M A T I C HYDROCARBON ( P A H s ) C r~Creosote consists of a mixture of PAHs ( 8 5 % ) ; 10% pheno l s and 5% _he t erocyc l i c compounds ( M u e l l e r e t al. 1 9 8 9 ) . For the purpo s e s ofthis risk assessment, the risk of PAHs and phenols wi l l be "^determined s epara t e ly . Most PAHs are carcinogenic and in general ct o x i c i t y increases as the molecu lar weight increases. CDA q u a t i c organisms accumulate PAHs f r o m contaminated f o o d . Wherea s s i m i l a t i o n of ingested PAHs was d e m o n s t r a t e d , me tabo l i sm andexcretion o f P A H s were rapid ( N e f f 1 9 8 2 ) .Below is a review of l i t e ra ture ava i lab l e on the e f f e c t s and thebioconcentration of a variety of PAHs. Most l i terature isr e f er enced i n E i s l e r ( 1 9 8 7 ) a n d U S E P A ( 1 9 8 0 ) .A l g a eLu et al. ( 1 9 7 7 ) reported that in a laboratory sys t em,b e n z o ( a ) p y r e n e h a d a m o d e l l e d bioconcentration f a c t o r ( B C F ) o f 5258for the a l g a , Oedoaonl^m f f f t P r l i y c u . m . F o r the purpose s o f this riskasse s sment, thi s value w i l l be used.A t h e y et al. ( 1 9 8 9 ) used sediment e l u t r i a t e f r o m a wood t r ea t ing( c r e o s o t e ) s i te for a bioassay with the green a l g a , S e l e n a s t r u mcapricornutum. Two e l u t r i a t e s were t e s t e d , one with aconcentration of 25 ppm creosote, and one with a concentration of6% creosote. An e f f e c t concentration of 50% (EC^ was obtained ina s o lu t i on composed of 64% of the 25 ppm creosote e l u t r ia t e .A s s u m i n g that a s o lu t i on containing 36% uncontaminated waterrepresents a 36% d i l u t i o n f a c t o r , the alga was exposed to 16 ppmcreosote. An EC^, was obtained in a s o lu t i on composed of 42% of the6 ppm creosote e l u t r i a t e ( 2 . 5 ppm cr eo so t e). A c a l c u l a t e d LOAEL of1.6 ppm creosote w i l l be used in the risk assessment.F o r a g e F i s hS o u t h w o r t h ( 1 9 7 9 ) c a l c u l a t e d a BCF of 485 for anthracene a f t e r a 2- 3 day exposure. Lu, et al. e s t imated a BCF for b e n z o ( a ) p y r e n e at930 for Gambusia exposed for 3 days. For the purpo s e s of the riskasse s sment, the BCF value of 930 w i l l be used.

F i n g e r et al. ( 1 9 8 5 ) tested f l u o r e n e on a variety of aquaticorganisms. F a t h e a d minnow were tested in a 96 hr bioassay andexhibited an LC0 of >100,000 M 9 / l « However, rainbow troutexhibited an LC^ of 820 M 9 / L of f luorene and j u v e n i l e minnow( P o e c i l i o p s i s ) in a 20 hr exposure had an LC 1 0 0 of 500 ng/I 7,12-dime thy1-benz(a)anthrac ene ( S c h u t z and S c h u t z , 1 9 8 2 ) . For thepurpose s of this s tudy, a ca l cu la t ed LOAEL of 50 ng/1 w i l l be used.Piscivorous F i s hSeveral t e s t s have been conducted on the de t erminat ion of a BCF inb l u e g i l l . A BCF of 12 was measured a f t e r a 4 hour exposure tob e n z o ( a ) p y r e n e (Leversee et al. 1 9 8 1 ) . McCarthy and J i m e n e z( 1 9 8 5 ) noted a value of 225 for b e n z o ( a ) p y r e n e a f t e r 48 hr. in cwater conta ining 20 mg/1 d i s s o lv ed humic material and F i n g e r et al. or( 1 9 8 5 ) noted a value of 200 - 1800 a f t e r a 30 day exposure to \cf l u o r e n e . A BCF of 1800 wi l l be used for b l u e g i l l s in th i s risk ^assessment. C-*Several s tudie s have been conducted on the e f f e c t s of a variety ofPAHs to b l u e g i l l . EPA ( 1 9 8 0 ) indicate s an LC 8 7 o f 1000 / i g / 1b e n z o ( a ) a n t h r a c e n e a f t e r a 6 month exposure. F i n g e r et al. ( 1 9 8 5 )e s t imated an L C 1 2 of 500 A t g / 1 for a 30 day exposure and an LC^ of910 j u g / 1 for a 96 hour exposure to f l uor ene . For the purpose s ofth i s as se s sment, a c a l c u l a t e d LOAEL of 91 M 9 / 1 w i l l be used.S m a l l MammalEPA ( 1 9 8 0 ) and Lee and Grant ( 1 9 8 1 ) ind i ca t e that unsub s t i tu t edPAHs do not accumulate in mammalian a d i p o s e t i s sue , p r o b a b l ybecause they tend to m e t a b o l i z e r a p i d l y . T h e r e f o r e , for thepurpo s e s of this s t udy , in the ca l cu la t i on of dose to mammals , aBAF w i l l not be used.Chronic oral doses of a variety of PAHs shown to have carcinogenice f f e c t s in rodents have been determined ( S i m s and Overcash, 1 9 8 3 ) .T h e y range f r o m 0.002 m g / k g bodyweight b e n z o ( a ) p y r e n e to 3 ,300m g / k g body weight anthracene. A l s o , a s tudy by S c h a f e r and Bowles( 1 9 8 5 ) l i s t a concentration o f 825 m g / k g body weight f or f o o dconsumption (5 d a y ) o f 2-methooxynaphthalene (30% reduct ion) forPeromyscus m a n i c u l a t i s . For the purpo s e s o f thi s s t u d y , theobserved LOAEL of 0.002 m g / k g body w e i g h t / d a y w i l l be used.Red FoxNo l i t e r a t u r e values were f o u n d f or t o x i c i t y o f PAHs to r ed f o x .Sax and Lewis ( 1 9 8 9 ) cited a LDL O oral dose to dogs of 500 m g / k gwhich was assumed to be equivalent to a L O A E L . For the purpose s ofth i s risk assessment the 500 m g / k g diet was converted to 12.5m g / k g / d a y by a d j u s t i n g for body weight and inge s t i on rate for asurrogate s p e c i e s , t h e d o g ( N I O S H , 1 9 8 2 ) .

MidgeChironomids are o f t e n a f o od source for a variety of aquatic l i f e .Several studies were conducted in which the e f f e c t s of PAHs weredetermined. Leversee et al. ( 1 9 8 1 ) determined a BCF forchironomids of 166 for Chironomus riparius a f t e r an 8 hour exposurewhich was used in this risk assesssment.

D I O X I NThe term polychlorinated dibenzo-E-dioxin ( P C D D ) , or dioxin, re f er sto 75 isomers that d i f f e r in the number and pos i t ion of attachedchlorine atoms. 2,3,7,8-Tetra-chlorodibenzo-E-dioxin ( 2 , 3 , 7 , 8 - ^TCDD) is considered to be the most toxic of these isomers.lexicological and biological propert i e s of this isomer have beenintensively s tudied, while information regarding other isomers is ^scarce. 2 , 3 , 7 , 8 - T C D D is h igh ly s table , readily incorporated into *=^aquatic and terrestrial ecosystems, and extraordinarily persistent O(Ei s l e r 1 9 8 6 ) . 2 , 3 , 7 , 8 - T C D D has been reported to comprise from 40 ^to 95% of the total body burden of PCDDs detected in various ^_organisms ( E i s l e r 1 9 8 6 ) . For purposes of this risk assessment,toxic proper t i e s of 2 , 3 , 7 , 8 - T C D D (hence for th referred to as TCDD)are u t i l i z ed to assess risk from dioxin exposure at this site.Exposure to TCDD has been reported to result in l e t h a l ,carcinogenic, teratogenic, mutagenic, reproductive, h i s topathologicand immunotoxic e f f e c t s . TCDD accumulates in liver and adipo s etissue of vertebrates ( Y o u n g and Cockerham 1 9 8 5 ) . El iminat ionrates of ingested TCDD are similar across species, and range f r om10.8 to 30.2 days for 50% el imination ( E i s l e r 1 9 8 6 ) .Long-term studies have been conducted on w i l d l i f e exposed to TCDDat E g l i n Air Force Base, F l o r i d a ( Y o u n g and Cockerham 1 9 8 5 ) . H i g hTCDD residues have been detected in tissues of some species (be e t l elarvae, beachmouse, Southern toad, meadowlark), while nocontamination has been detected in other species (deer, opossum,g r a s s h o p p e r ) . The authors state that contaminated organisms areeither c l o s e ly associated with soil or ingest soil-borne insects.The magnitude of tissue contamination was correlated with levels ofTCDD in soi l s where the animals were co l l e c t ed .Below is a review of literature available on the e f f e c t s and thebioconcentration or bioaccumulation of dioxins.A l g a eA f t e r 32 days of exposure to a water concentration of 0.1 ppt T C D D ,Yockim et al. ( 1 9 7 8 ) reported a BCF of 2083 in O. cardiacum.Issensee and Jone s ( 1 9 7 5 ) examined f a t e of 1 4 C - T C D D added to so i l splaced in laboratory microcosms. A f t e r 31 days of exposure (so i ll eve l s , 0.001 p p m ; water concentration, 0.26 p p t ) a BCF of 5400 wasmeasured in 0. cardiacum. A BCF of 5400 will be ut i l ized forpurposes of this risk assessment.

An LCgg of 1.3 j i g / l i t e r was reported for the algacardiacum (U.S. EPA 1 9 8 5 ) . A cal cu la t ed LOAEL of 0.13 p g / l i t e rwill be used in this risk assessment.Forage F i s hIn f a t h e a d minnows, a BCF of 158 for 2 , 3 , 7 , 8 - T C D D was reported( T s u s h i m o t o e t a l . 1 9 8 2 ) . However, U . S . EPA ( 1 9 8 5 ) s tates thatwater concentrations of TCDD were measured improper ly in thiss tudy, and the BCF was undere s t imated. Corbet et al. ( 1 9 8 3 )conducted bioconcentration te s t s on 1 , 3 , 6 , 8 - T C D D with f a t h e a dminnows, and reported a s t eady state BCF of 1061. Clearance ratesfor 1 , 3 , 6 , 8 - T C D D were also measured, and reported to be 10 to 15times greater than rates measured for the 2 , 3 , 7 , 8 - T C D D isomer. For ^purpose s of this risk assessment, a BCF of 1061 wil l be used for (Xthe f a t h e a d minnow. \c

«3No data could be f o u n d for toxic e f f e c t s o f TCDD on f a t h e a dminnows. Yock im et al. treated s o i l s with 0.1 ppm TCDD, andmeasured water concentrations of 3.4 ppt ( d a y 1 of e xp er imen t) and *2.6 ppt ( d a y 1 5 ) . T h e y reported 100% m o r t a l i t y in Gambusiaa f f i n i s . m o s q u i t o f i s h , by day 15. M i l l e r e t a l . ( 1 9 7 9 ) reportedan LCgo o f 0.001 / i g / l i t e r f o r g u p p i e s , P o e c i l l a r e t i cu la ta . Forpurpose s of th i s risk assessment, the LC^ value (0.001 / i g / l i t e r )wi l l be used to assess risk to f o r a g e f i s h , giving a c a l c u l a t e dLOAEL of 0.0001 j i g / l i t e r .Piscivorous F i s hLitera ture values for b ioconcentrat ion and t o x i c i t y o f TCDD tob l u e g i l l s were not f o u n d . A s t eady-s ta t e BCF of 5450 was reportedfor rainbow trout exposed to 0.107 jig T C D D / l i t e r . Regressionequations can a l s o be used to e s t imate BCF values based on theoctanol-water p a r t i t i o n c o e f f i c i e n t f o r T C D D . U s i n g th i sregression equation, a BCF of 3000-68,000 is p r e d i c t e d . However ,a v a i l a b l e measured B C F s range f r o m 390-13,000. T h e U . S . E P A ' s bestcurrent ( 1 9 8 5 ) e s t imate for the BCF of TCDD in aquatic organisms is5000. For purpos e s of th i s risk as se s sment, a BCF of 5450 forpi sc ivorous f i s h w i l l be used.Early l i f e s tages of S a lino aairdneri (rainbow t r o u t ) and Esoxlucius ( p i k e ) were exposed to 0.01 / i g / l i t e r TCDD for 96-hours( H e l d e r 1 9 8 2 ) . S i g n i f i c a n t growth reduction was noted in j u v e n i l erainbow trout. T h i s level of exposure resulted in 100% m o r t a l i t yof trout yo lk sac f r y , and almost 100% m o r t a l i t y of p ike embryos.M i l l e r e t a l . ( 1 9 7 3 ) examined d i e tary t o x i c i t y o f TCDD to rainbowtrout. Growth reduct ion and m o r t a l i t y were noted in f i s h receivingdi e tary l e v e l s of 0.9 nq T C D D / k g / d a y . Because exposure through thef o o d chain is being evaluated in thi s risk asses sment, a dose of0.9 / u g / k g / d a y w i l l be used to assess risk to a pi s c ivorous f i s h .

S m a l l mammalYoung and Cockerham ( 1 9 8 5 ) analyzed soil from burrows, and tissuesof Peromyscus po l ionotu s . Reported TCDD leve l s were: s o i l s , 285p p t ; f e m a l e s , 1,900 p p t ; and males, 2,600. Concentration fac tor swere 6 to 7 for f e m a l e s , and 18 to 19 for males. For purposes ofthis risk assessment, a concentration f a c t o r of 13 wi l l be used.M u l t i g e n e r a t i o n reproduction and l i f e t i m e chronic t o x i c i ty s tudieshave been comple t ed for TCDD with Sprague-Dawley rats ( K o c i b a andSchwe tz 1 9 8 2 ) . The LOAEL reported and used in the risk assessmentwas 0.01 M g / k g / d a y , and the no observable adverse e f f e c t level(NOAEL) was reported as 0.001 ^ g / k g / d a y . KRed Fox or

vCNo l i t era ture values could be located for toxic e f f e c t s o f TCDD on ^f o x e s . Schwetz et al. reported 100% morta l i ty in dogs given as i n g l e oral dose of 3.0 m g / k g T C D D . Anorex ia , a l o p e c i a and cin t e s t inal hemorrhage were noted in dogs receiving and s i n g l e oraldose of 0.03 m g / k g TCDD, however only two dogs received this dose.Sax and Lewsi ( 1 9 8 9 ) cite an oral LD^ value of 1 M S / k g for dogs.For purpose s of this risk assessment, the reported LD^ value of 1M g / k g ( c a l c u l a t e d LOAEL of 0.1 M g / k g ) w i l l be used to assess riskto f o x e s u t i l i z i n g contaminated prey f r o m this site. Thec a l c u l a t e d LOAEL of 0.1 M / k g was converted to ^ i / k g / d a y by a d j u s t i n df o r body weight a n d inges t ion rate f o r t h e d o g ( N I O S H , 1 9 8 2 ) .Benthic invertebratesBenthic invertebrates are a f o o d source for f i s h and w a t e r f o w l .U p t a k e and b ioconcentrat ion of 1 , 3 , 6 , 8 - T C D D by Chironomus t entans( m i d g e ) and Hexagenia r ig ida ( m a y f l y ) were measured in two types ofs ediment. M i d g e s in sandy sediments had a 96 hour BCF of 4135,whi l e in s i l t y sediment the 96 hour BCF was 4682. Bioconcentrationf a c t o r s measured for m a y f l i e s were 5291 and 5399 for sand and s i l ts ed imen t s , r e s p e c t i v e l y .

P E N T A C H L O R O P H E N O L ( P C P )PCP ( C 6 H C 1 5 O ) is a synthe t i c organochlorine compound that isp r i m a r i l y used as a wood preservative and s e condar i ly as aherb i c id e , in s e c t i c i d e , f u g i c i d e , m o l l u s c i c i d e and bacter ic ide .PCP is very uns table in the environment and is r e a d i l y degraded bychemical , microbiological and photochemical processes.Exposure to PCP has been reported to result in l e t h a l , f e t o t o x i cand t eratogenic e f f e c t s , but evidence for mutageni c i ty andcarc inogenic i ty i s s t i l l in compl e t e . A l t h o u g h PCP i s r a p i d l y takenup by biota it is also r a p i d l y excreted and has l i t t l e tendency toper s i s t in l i v i n g organisms.

A l g a eGotham and Rhee ( 1 9 8 2 ) studied the bioconcentration of POP in thea lgae Ankis trodemus f a l c a t u s at concentrations ranging from 9 to 22fjtg/li. They noted that the bioconcentration f a c t o r s wereindependent of the POP concentration, however, they were correlatedwith culture dens i t i e s . The greatest bioconcentration f a c t o r , 320,was observed at the lowest culture dens i ty while the smallbioconcentration f a c t o r , 100, was seen at the highest culturedens i ty. For the purpose of this risk assessment a BCF of 320 wi l lbe used.Gotham and Rhee ( 1 9 8 2 ) found that PCP in concentrations between 1.0and 1.3 M g / L over a 11 day period inhibited photo synthe s i s in both ^A. f a l c a t u s and Micro cy s t i s s p . , and reduced the growth rate in orMelo s i ra sp. Since the results in this study were at the c e l l u l a r vClevel and may not have s i g n i f i c a n t e f f e c t s at the p o p u l a t i o n level «_,data c o l l e c t ed by Huang and G l o y n a ( 1 9 6 8 ) w i l l be used to determinethe low observed apparent e f f e c t level (LOAEL) for algae. Huangand G l o y n a ( 1 9 6 8 ) observed compl e t e de s truc t ion of c h l o r o p h y l l in ®the a lgae C h l o r e l l a pyreno ido sa within 72 hours of in troduc t i on ofPCP at a concentration of 7.5 / i g / L .F o r a g e f i s hLiterature values for bioconcentration of PCP in f a t h e a d minnowswere not f ound . S t e h l y and H a y t o n ( 1 9 9 0 ) studied the e f f e c t s of pHon bioconcentrat ion of PCP in g o l d f i s h (Caras s iu s a u r a t u s ) . In a96 hour s tudy, exposure to 5 M 9 / L PCP resul ted in b ioconcentrat ionf a c t o r s f r o m 52 to 607 in the g o l d f i s h . The greatestbioconcentrat ion f a c t o r s were observed at pH 7 and the s m a l l e s tbioconcentration f a c t o r s were observed at pH 9. Since the pH ofthe streams and lakes at the American Creosote S i t e is not known,the more conservative bioconcentration f a c t o r of 607 w i l l be usedin this risk assessment.C l e v e l a n d et al. ( 1 9 8 2 ) observed a reduction in growth in thef a t h e a d minnow a f t e r a 90 day exposure to 85 / i g / L of P C P .Concen tra t i on s as low as 120 / i g / L of PCP have been es t imated as theLCgo for the f a th ead minnow ( E i s l e r , 1989) . A LOAEL of 85 M 9 / L usedin the risk assessment.Piscivorous f i s hThe only study of PCP accumulation in the b l u e g i l l measured PCPaccumulation in f o u r type s of t i s sue and not as a whole bodyb ioconcentrat ion f a c t o r . A f t e r an 8 day exposure to 100 Mg/L ofP C P , bioconcentration f a c t o r s were as f o l l o w s : 13 in the muscle, 60in the g i l l s , 210 in the ga s t r o in t e s t ina l tract and 350 in thel iver ( P r u i t t et al. 1 9 7 7 ) . Based upon the re la t ive mass of eachof these t i s sue s , an e s t imated whole body b ioconcentrat ion f a c t o rof 80 w i l l be used for this risk assessment.

S a m i s et al. ( 1 9 9 1 ) reported b lu eg i l l sun f i s h exposed to asubchronic exposure of 24 u g / L (10% of the LCgJ of PCP showeds i g n i f i c a n t reductions in f o od conversion e f f i c i e n c y measuredduring the last 10 days of exposure. A value of 24 / i / L (10% of the) w i l l be used as the LOAEL for b l u e g i l l s exposed to P C P .S m a l l MammalNo bioaccumulation f a c t o r s of PCP were found for any species ofsmall mammal.No data could be f o u n d on the toxic e f f e c t s of PCP on the deermouse. Mice (Mus musculus) fed 50 m g / k g dietary PCP for 10 to 12weeks showed a s i g n i f i c a n t increase in s u s c e p t i b i l i t y to tumor ^growth ( K e r k v l i e t et al. . 1 9 8 2 ) . NIOSH ( 1 9 8 5 ) observed the s ing l e

the site. A d d i t i o n a l l y , soil examined immediately adjacent to theCreosote Branch, drainage di t che s , road and rail beds werer e f l e c t i v e of historic disturbance and showed a p r o f i l e consistingof al ternating layers of organic material, sand, and a tar-likematerial. A l t h o u g h the remains of demol i t ion activit ies currentlyare s t o ckp i l ed in the northwest corner of the former treatmentarea, most surface contaminant sources have been el iminated.Potent ia l release and transport mechanisms may includev o l a t i l i z a t i o n , r u n o f f , and leaching. V o l a t i l i z a t i o n o fcontaminants f rom the American Creosote site would include thedirect release to the air of l i gh t e r molecular weight compoundsf r o m areas such as the tar mat. Because most of the contaminantspresent on site are heavy molecular weight compounds, this is not v£expected to be a m a j o r release mechanism. T h i s is f u r th e r orsuppor t ed by the re sul t s of the ambient air monitoring conducted on ^this site in 1987, in which none of the suspected v o l a t i l e organic ^compounds ( p r i m a r i l y benzene and to luene) were detected in airsampl e s . A p o t e n t i a l except ion to this as sumption would be the cexposure of organisms inhab i t ing subsurface burrows or the ground €3surface in the vicinity of release areas. S o i l gas data indicatedthat vapor c o l l e c t e d f r o m the site contained elevatedconcentrations of benzene and toluene. T h i s was as soc iated with aplume that extended in an eastern direct ion from treatment area totar p i t s . T h i s l a t t e r exposure scenario would be most s i g n i f i c a n tto small f o s s o r i a l mammals and soil invertebrates.R u n o f f is a mechanism involving the movement of water f r o m areas ofhigher e l evat ion to lower elevation. T h i s process consequentlyinvolves abrasion, mechanical wear, and transport of soil p a r t i c l e sin a water media. Erosion and transport is expected to contributeto the movement of contaminants at the American Creosote s i t e dueto the humid sub tropical c l imate as well as the presence ofdrainage d i t ch e s associated with wood trea t ing. T h i s process w i l lmost l i k e l y result in a net movement of soil and as soc iatedcontaminants in a westward and northward d irec t ion into thef o r e s t e d wet land and u l t i m a t e l y Creosote Branch.Leaching is the p e r c o l a t i o n of water or other l i q u i d s through aporus med ia; in the proces s , s o lub l e mat er ia l s such as mineral s ,metals and contaminants may enter into solution and move bothh o r i z o n t a l l y and v e r t i c a l l y . The l eaching process is enhanced byporous media as well as frequent and intense storm events. Thes o i l s in the v i c ini ty of Creosote Branch are very d e e p , p o o r l ydrained and very p o o r l y d r a i n e d , s l o w l y permeable s o i l s . F u r t h e rwest , in the v i c in i ty of the f ormer treatment f a c i l i t y , the s o i l sare somewhat de eper , poor ly drained, and s l o w l y permeable (seewet land s e c t i o n ) . At the time of the s tudy, much of the acreage tothe north of the treatment f a c i l i t y was f l o o d e d and soil wassaturated to the surface . The banks of the Creosote Branch showeda th ick u n d e r l y i n g layer of darkened s o i l , a p p a r e n t l y contaminatedwith creosote, at a d e p t h of about six f e e t below the s u r f a c e .T h i s exposed and r e l a t i v e l y erodib l e material may account for thesheen observed on the waters s ur fa c e . It is u n l i k e l y that l eaching

wi l l account for much movement of site contaminants. The presentextent of subsurface contamination is most l i k e l y associated withhistoric wood treat ing activit ies . Further aromatic hydrocarbonsand other creosote compounds t y p i c a l l y do not move r a p i d l y throughthe soil by their own accord, rather they are mobilized by a non-p o l a r carrier f l u i d . The observed d i s tr ibu t ion of contaminants atthe site may be a f u n c t i o n of this f a c t as well as in f erredproduction activities. The materials observed in soil p r o f i l e s maybe the result of dr ip-drying treated wood products in this area.The h i g h l y compacted sur fac e s o i l s and hardpan as well as thev o l a t i l i t y of the carrier f l u i d prevent rapid and extensivedownward migration. In contrast, the material observed in thestream bank may be present at increased d e p t h s due to the largervolumes of l iquid ( i . e . , so lvent) depos i ted there. ror

I N D I C A T O R S P E C I E S ^

are combined in the chemical s p e c i f i c bioconcentration fac tor s .T e r r e s t r i a l l y , dermal contact would not be as extensive as that inwater but could be a s i g n i f i c a n t exposure route for burrowinganimals.The other exposure route which the risk assessment will concentrateon is the inges t ion route. T h i s exposure route requires that thechemicals of concern are incorporated into the f o od web s p e c i f i cfor the indicator species. The mechanism of the initial movementinto the f o o d is for the purpose s of this risk assessmentunimportant. Assumpt i on s are made based on the l i t erature reviewedas to the amount of chemicals incorporated into the f o o d web.T h e s e a s sumptions are based on the best i n f o r m a t i o n ava i lab l e atthis time. BCF and BAF data obtained f rom the l i terature are ftpresented in T a b l e 7. Most of the l i t era ture obtained for this arisk assessment is based on s p e c i f i c a l l y ingested doses and the ^natural history of the indicator species. ^

£**"-The f o l l o w i n g exposure pathways are evaluated in thi s risk *•'assessment:Fathead minnowS u r f a c e water exposureI n g e s t i o n o f sedimentI n g e s t i o n of p lan t materialI n g e s t i o n o f benthic invertebratesB l u e g i l lS u r f a c e water exposureI n g e s t i o n of benthic invertebratesI n g e s t i o n o f f i s hI n g e s t i o n o f a lgaeI n g e s t i o n of sedimentDeer mouseI n g e s t i o n o f insectsI n g e s t i o n o f vege ta t ionRed foxI n g e s t i o n o f small mammalsL i f e hi s tory i n f o r m a t i o n u t i l i z e d in the c a l c u l a t i o n s i s summarizedbelow. Contaminant l e v e l s used in risk c a l c u l a t i o n s are presentedin T a b l e 12.Fathead MinnowAn average adul t f a t h e a d minnow weighs 2.5 g ( S t a r r e t t 1 9 5 0 ) .I n g e s t i o n rates for fa th ead minnows could not be f o u n d , so aninge s t i on rate for small f o r a g e f i s h cited by Seaburg and M o y l e1964 (2% of body weight d a i l y ) was used. The diet i s e n t i r e l ycomposed of bottom ooze ( S t a r r e t t 1 9 5 0 ) , which includes s ediment,benthic invertebrates , and p l a n t mater ia l . For purpose s o f thisrisk assessment, it is assumed that each component of the bot tom

ooze comprises 33% of the d i e t , and that a f a t h e a d minnow obtains100% of its diet f rom the American Creosote site.To ca l cu la t e d i e tary uptake of contaminants by f a t h e a d minnows, thef o l l o w i n g equations were used:Contaminant in sediment ( C S ) :Contaminant in p l a n t s (CA): BCF p l a n t s X CSContaminant in benthos ( C B ) : BCF benthos X CSContaminant dose = [CS X 0 . 3 3 ] + [CA X 0 . 3 3 ] + [CB X 0 . 3 3 ]Dose = Contaminant dose X ingestion rate X I / m i n n o w body weightDose ca l cu la t i on s are summarized in T a b l e 6. ^\CContaminant dose (in m g / k g ) is d e f i n e d as the contaminant

Dose calculations are summarized in T a b l e 6.Besides ingest ion of the d a i l y contaminant dose, f i s h also take upcontaminant concentrations f r om water through g i l l s(bioconcentrat ion) . The f o l l o w i n g equation was used:Contaminant in water (CW) :B l u e g i l l - BCF b l u e g i l l X CWThe total d a i l y dose - Dose + Blueg i l l uptake

Deer MouseAn average adult deer mouse (Peromyscus m a n i c u l a t u s ) weighs 20grams ( M i l l a r , 1 9 8 9 ) . I n g e s t i o n rates for the deer mouse were notava i lab l e in the l i t e ra tur e , so ingestion rates for thee c o l o g i c a l l y s imi lar w h i t e - f o o t e d mouse ( Peromyscus 1 eucopus ) ,0.142 g/g body w e i g h t / d a y , were used ( L i n z e y 1 9 8 7 ) . An adul tw h i t e - f o o t e d mouse w i l l ingest a p p r o x i m a t e l y 2 .8 g / d a y . The f o o dhabit s of the deer mouse vary with habitat occupied and theseasonal a v a i l a b i l i t y of f o o d . Overall the most common observedf o o d s in the d i e t s of deer mice include s eeds , insects and greenp l a n t s (Montgomery 1989) . For the risk assessment it wil l beassumed the diet consis t s of: 45% invertebrates and 50% p lan tmater ia l . The home range of the deer mouse is es t imated to bebetween 0.01 and 1 hectare ( M e r r i t t 1 9 8 7 ) , so it w i l l be assumedthat the deer mouse obtains 100% of its diet f r o m the contaminatedarea.To c a l c u l a t e d i e tary uptake of contaminants by deer mice, thef o l l o w i n g equations were used:Contaminant in soil (CSL) :Contaminant in invertebrates (CI) : BCF invertebrates X CSLContaminant in t erre s tr ial p l a n t s ( C P ) : BCF t erre s tr ia l p l a n t s XC S LContaminant dose = [ C I X 0 . 5 ] + [ C P x 0 . 5 ]Dose = Contaminant dose X inges t ion rate X I / d e e r mouse bodyweightDose c a l c u l a t i o n s are summarized in T a b l e 6.

Red FoxRed fox were included in this risk assessment to evaluate the riskof u t i l i z a t i o n of the American Creosote site by a carnivorousmammal. An average a d u l t fox weighs 5 kg and can consume 0.32 kgof f o o d per day, with the main f o o d item being small mammals( S a m u e l and N e l s o n 1 9 8 2 ) . In order to not overestimate theexposure , an area use f a c t o r was ca l cu la t ed to weigh the e s t imateddose by the propor t i on of time the animal would use the

contaminated resource. T h i s ca l cu la t ion assumes that time andspace a l l o ca t i ons are d i r e c t l y p r o p o r t i o n a l , and does not accountfor d i f f e r e n t i a l habitat use. A l s o , this ca l cu la t ion does notconsider loss of contaminant f r o m the body during the period of theyear the red fox does not u t i l i z e the contaminated area. Homerange sizes ranging f r om 57.5 to 161.9 ha have been reported(Samue l and N e l s o n 1 9 8 2 ) . A home range size of 110 ha ( 4 4 . 5 acres)was used for purpose s of this risk assessment. The AmericanCreosote site is a p p r o x i m a t e l y 32 acres in size. T h e r e f o r e , it isassumed that a fox would obtain 72% of its diet f r o m the site.To ca l cu la t e die tary uptake o f contaminants by f o x e s , the f o l l o w i n gequations were used:Contaminant in soil (CSL): vContaminant in small mammals ( C M ) : BAF small mammals X CSL c

vCDose = Contaminant in small mammals X inge s t i on rate X area usef a c t o r X I / f o x body weight "^Dose c a l c u l a t i o n s are summarized in T a b l e 6. ®

R I S K C H A R A C T E R I Z A T I O NTo estimate risk to w i l d l i f e u t i l i z i n g the American Creosote s i t e ,i m p l i c a t i o n s of the exposure concentrations need to be determined.The hazard quotient method ( U . S . EPA 1 9 8 9 ) compares exposureconcentrations to e co logical endpo in t s ( e . g . reproduct ion or growthe f f e c t s ) . The comparisons are expressed as ratios of p o t e n t i a lintake values to p o p u l a t i o n e f f e c t l e v e l s , or:

_______Exposure concentration_____Level shown to cause eco logical e f f e c t = H a z a r d Quotient(Low Observed Advers e E f f e c t s Level ( L O A E L ) )A hazard quotient greater than 1 indica t e s that exposure to thecontaminant w i l l l i k e l y cause d e l e t e r i ou s h ea l th e f f e c t s . T h i s i sa very l iberal approach as, in th i s p a r t i c u l a r as se s sment,uncertainty f a c t o r s for the most part have not been i n c l u d e d . Asnoted in the uncertainty analy s i s , the uncertainty associated withthi s type of l i t e ra tur e based risk assessment is very high. W i t hall other variable s he ld constant the a d d i t i o n of as sociateduncertainty f a c t o r s would g e n e r a l l y increase the risk by reducingthe L O A E L s .Actua l c a l c u l a t i o n s of the hazard quot ients and the r e s u l t s of thec a l c u l a t i o n s are pre sented in T a b l e s 8 - 1 1 .Uncertainty A n a l y s i sThe risk assessment conducted for the American Creosote s i te wasbased on a l i t e ra tur e review and a minimum amount of t o x i c i t yt e s t i n g . The l i t e ra ture review rel ie s almost e x c l u s i v e l y on

laboratory experiments with c a r e f u l l y controlled conditions ands ingle chemical exposures. The m u l t i p l e chemical exposure scenarioat the American Creosote site requires that the exposures beintegrated and evaluated as to their interactions. I d e a l l y , sites p e c i f i c chemical analys i s o f indigenous biota s p e c i f i c a l l yaddresses the interactions of the chemicals as the biota sampledhas ac tua l ly been exposed to the site s p e c i f i c mixture ofchemicals. U n f o r t u n a t e l y , site s p e c i f i c residue data was notavai lab l e . Interac t i on s among the chemicals include a d d i t i v i t y ,synergism, antagonism and p o t e n t i a l l y combinations of these. Eachof these interactions would normal ly require a par t i cu laruncertainty f a c t o r to be added to the risk assessment. Uncer ta intyf a c t o r s g enera l ly range f r o m one to 10,000. Much of the dataobtained through the l i t erature review was not in a usable f o r m andneeded to be t rans formed into a f o r m which would fit theca l cu la t i on s necessary for the risk assessment. LC^s and EC^s weret ran s f o rmed to LOAELs by d i v i d i n g the LC and EC ^s by 10 and anyt r a n s f o r m a t i o n s to N O A E L s were ca l cu la t ed by d i v i d i n g the LC and EC508 by 100. W h i l e this is not a precise c a l c u l a t i o n and adds as i g n i f i c a n t uncertainty term into the c a l c u l a t i o n s thet r a n s f o r m a t i o n s are necessary for the c a l c u l a t i o n .We have not added any uncertainty f a c t o r s for the cross spec i e se x t r a p o l a t i o n of the data f rom the l i t erature review and we haveassumed that the LOAELs derived f r o m the LC^, values area p p r o p r i a t e . We have al so assumed there are no interact ions amongthe chemicals that the biota are exposed to at the AmericanCreosote site. Many of these as sumptions are not va l id and wouldrequire a p p l i c a t i o n of uncertainty f a c t o r s f r o m 1 to 10,000. Wehave not a p p l i e d uncertainty f a c t o r s as we are c o n f i d e n t that forthe purpo s e s of th i s base l ine risk assessment a generic statementof risk would be adequate. A more quant i ta t ive risk assessmentwould require add i t i ona l work on the site to evaluate the s p e c i f i cuncer taint i e s as soc iated with the bas e l ine risk assessment.The uncertainty f a c t o r s g e n e r a l l y increase the ca l cu la t ed risk bya p p a r e n t l y increasing the t o x i c i t y , by a f a c t o r of 1 to 10,000, toaccount for unknown variables. The risk assessment c a l c u l a t e d f r o mthe l i t e ra ture values has a high degree of uncertainty associatedwith it. I n c l u d i n g the number and type of uncertainty f a c t o r s ,p r o b a b l y necessary, would result in a risk assessment that would beu n i n t e r p r e t a b l e . T h i s risk a s s e s s m e n t ' s value i s in the generals ta t ement s of risk even if the s ta tement s are couched inuncer ta int i e s that result in a very l iberal statement of risk.C O N C L U S I O N SThe e c o l og i ca l risk assessment conducted for the American Creosotes i te in W i n n f i e l d Louis iana was based on a l i t e ra ture review asthere were no site s p e c i f i c tissue residue level s to be integratedinto the risk assessment. S o i l , sediment and s u r f a c e or groundwater contaminant l ev e l s were integrated through a number ofca l cu la t ions to approximate the residue or t ox i c i ty l eve l s in theind i ca t or specie s .

The American Creosote site is pre s ent ing a s i g n i f i c a n t risk toseveral species either present on the site or p o t e n t i a l l y presenton the site. For the purposes of this risk assessment s i g n i f i c a n trisk is determined to be l eve l s of contaminants that exceed theLOAEL. Exceeding the LOAEL indicates that there would be anadverse e f f e c t on the species investigated. The LOAELs have beenintegrated with the exposure concentrations to ca l cu la t e the hazardquotient with unity at the point that the exposure concentration isequal to the LOAEL. Numbers greater than one denote higher riskand numbers lower than one would denote less risk.A l g a e hazard quotients only exceed one for PCP and are below onefor d i o x i n , other pheno l s and PAHs. The PCP hazard quotient isca l cu la t ed to be 2,907. U n f o r t u n a t e l y , this hazard quotient ishigh enough that a p o p u l a t i o n of a lgae exposed to l eve l s of PCPfound in the surface water at the site would be k i l l e d in less than72 hours.Fathead minnows exposed to PAHs in surface water at the AmericanCreosote s i te have a hazard quotient of 644 T h i s l e v e l , when backca l cu la t ed to the l i t erature numbers u t i l i z e d , shows that the LC^for f a t h e a d minnows is exceeded by almost two orders of magnitude.Based on thi s c a l c u l a t i o n one would not expect minnows to survivein the s u r f a c e water associated with this site. PCP l eve l s at thes i te result in a ca l cu la t ed hazard quotient of 487. S i m i l a r backcalculat ions show that the LCg- for minnows is exceeded by a f a c t o rof 48.7. A reasonable as sumption is that minnows would not surviveat the site with the detected PCP l eve l s . The hazard quotient forphenol s other than PCP ( 0 . 1 7 ) does not appear to present mucha d d i t i o n a l risk to the risk presented by the PAHs and P C P .PCP appear s to present the only risk to b l u e g i l l s . The hazardquotient of 230 , back c a l c u l a t e d to an LC^, shows that the LC^ isexceeded by a f a c t o r of 23. A reasonable as sumption is thatb l u e g i l l s would not survive in the s i te water. H a z a r d quot ient sfor the other chemicals (other p h e n o l s , d iox in and PAHs) do notexceed one.The hazard quotient for exposure of deer mice to dioxins on theAmerican Creosote s i te is 800. The LOAEL is reproduct ive e f f e c t sand chronic t o x i c i ty . Based on these numbers one would only expectlow numbers of immigrant j u v e n i l e s on the site. The j u v e n i l e swould be r e p l a c i n g los ses to the assumed nonbreeding adultp o p u l a t i o n l i v ing on the site. Deer mice expose to PAHcontaminant l ev e l s in their diet have a hazard quotient of 3980.T h i s hazard quotient is based on cancer risk and has l imi t edu t i l i t y as mice in the w i l d , on average, do not live long enough tohave cancer risk present a serious impediment to the p o p u l a t i o n .The p h e n o l s , ex c ep t ing PCP which is evaluated i n d i v i d u a l l y , do notappear to add to the risk as the hazard quotient ( 0 . 1 1 ) approache st h e N O A E L ( 0 . 1 ) . T h e P C P hazard quotient ( 2 . 2 ) exceeds a unity ( 1 )and would contribute s l i g h t l y to the overall site risk.

Red Fox exposed to the d iox in l eve l s at the s i te , in their d i e t ,are not expected to survive as the hazard quotient, related tol e t h a l i t y , is 1200. We have used the l i t erature values for an LCg,.The other chemicals present ( P C P , PAHs and p h e n o l s ) do not appearto add s i g n i f i c a n t l y to this risk.The American Creosote site presents an unacceptable ecologicalrisk. The chemical residues in sur face water, sediment, and soilhave the po t en t ia l for e l imina t ing any p o p u l a t i o n s of the indicatororganisms re s iding on the site for any s i g n i f i c a n t amount of time.

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