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Contaminants of Concernat Scrap Yard Sites in NewZealand
Contaminants of Concernat Scrap Yard Sites in NewZealand
By Sarah Knowles & Jodi ThompsonBy Sarah Knowles & Jodi Thompson
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Introduction
• Scrap Yards, including automotive dismantling or wrecking yardsand scrap metal yards are listed in the Ministry for theEnvironment (MfE) Hazardous Activities and Industries List (HAIL).
• This paper will summarise the contaminants of concern that arelikely to be detected at scrap yards, with a presentation of thelikely soil contaminant concentrations that may be found. A casestudy will be presented to illustrate an investigation of a scrapyard that will highlight the site environmental conditions andcontaminant migration pathways of concern.
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Contaminants of Concern
The MfE Hazardous Activities and Industries List has metals,
hydrocarbons, and solvents as potential contaminants of
concern.
If transformers or capacitors have been received at the site there
is also potential for polychlorinated biphenyls (PCBs).
The range of contaminant concentrations encountered at nine
scrap metal yards in Southland and Bay of Plenty are shown in
the following slides.
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Metals
Sources of metal contamination include car batteries, scrap
metal and electrical components.
Range of Heavy Metal Concentrations
0.1
1
10
100
1000
10000
100000
Arsenic Cadmium Chromium Copper Lead Nickel Zinc
Co
nc
en
tra
tio
nm
g/k
g
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Hydrocarbons
Sources of hydrocarbons include fuel, lubricants, brake fluids,
oils and greases from scrap vehicles.
Sites may have diesel or oil storage in above ground storage
tanks or drums.
Range of Total Petroleum Hydrocarbon Concentrations
1
10
100
1000
10000
100000
C7 – C9 C10 – C14 C15 – C36
Co
nce
ntr
atio
nm
g/k
g
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Solvents
Solvents are typically associated with parts cleaning and wash
down bays.
The sites reviewed for this presentation did not have wash down
bays and solvents were not considered contaminants of concern.
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PCBs
PCBs are associated with electrical equipment.
Transformers will typically be drained of oil before being
received at the scrap yard but historically that has not always
been the case.
Range of PCB Concentrations
0
1
2
3
4
5
6
Total PCB (Sum of 35 congeners)
Co
ncen
tratio
n(m
g/k
g)
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Case Study
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Case Study Photos
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Conceptual Site Model
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Management Responses
Capping work areas to prevent soil and groundwatercontamination. This also mitigates human health exposurepathways (dermal contact and dust ingestion) wherecontaminated soil already exists.
Capture and treatment of stormwater generated onsite. Thestormwater treatment train may involve a trap for gross pollutants,an interceptor for hydrocarbons, a sand filter for dissolved metalsand if necessary backflow control.
Scrap metal yards will typically require a trade waste dischargeconsent and where soil and/or groundwater contamination ispresent may require a discharge to land consent. In all casesthese sites should have in place an Environmental ManagementPlan.
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