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Animas River Environmental Contamination from the Durango Mill Site

-Over 100 years of River Pollution-

Presenter: Norman R. Norvelle, WRRI Conference, San Juan College, May 17 & 18, 2016

Abstract

The Durango Colorado Mill Site contaminated the Animas River from 1880 to 1990. The

Animas River flows south into the San Juan River and onward to the Colorado River’s Lake

Powell. The Animas River is used as the agricultural and domestic water supply for Aztec,

Farmington, and Shiprock, New Mexico. The site was not only a mill, but also a smelter and

refinery. This was a processing site for lead from 1881 to 1930, for vanadium from 1942 to 1946

and for uranium from 1949 to 1963. The mine was closed in 1963 after a detailed radiological

study was conducted from 1953 to 1960. The site was designated a Superfund Cleanup site and

the cleanup occurred from 1986 to 1991.

The presentation will discuss the history, type of processing, and different contaminates for each

specific site use; lead, vanadium, and uranium. This will include loss of process solutions,

smelter stack gasses, and the various chemicals and metals released into the environment,

especially the river. An alarming amount of toxic materials were released.

Due to a greater availability of information more emphasis will be placed on uranium processing.

Information will include the release and monitoring of radioactive contaminants that forced the

closure and cleanup of the uranium processing site. Also, the presentation will contain

information on U.S Public Health Service’s (USPHS) human radiation exposure reports and the

Atomic Energy Commission’s (AEC) environmental radioactivity monitoring field lab, based in

Farmington that operated from about 1955 to 1965. A review will be given on measurement

units and laboratory instrumentation then and now. The Drinking Water Standards Maximum

Contamination Levels (MCLs) for radioactivity and for other metals will be discussed.

Introduction

Aztec, Farmington and the Animas valley have used and drank water contaminated by the

Durango Smelter Mill site for over 100 years. My family moved to Farmington in June of 1958.

We were from Oklahoma and followed the new oil & gas boom that was developing in the Four

Corners area. That fall I started the 7th grade in the Farmington Public Schools. My dad and our

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family loved fishing, hunting, and mineral prospecting. During the summer, every Friday night

or early Saturday morning we would head to the mountains, usually driving through Durango on

the way. I remember the old lumber mill and smelter mill. As we drove by the lumber mill scrap

wood would be burning in the fire tepee and coal would be burning in the smelter stack. The

mountain next to the smelter mill was named Smelter Mountain and everything on the side of the

mountain was dead due to the smelter’s acidic stack gases. The smelter had several large ponds

next to the river that were usually full and a deep green. Many times when we drove by the

ponds, the dirt walls and dikes retaining the acid process wastewater would be breached. The

ponds would be empty and on the river shore you could see where the contents went into the

river.

I loved science and so did my 9th grade physical science teacher. He was especially interested in

nuclear energy. Our teacher used to work in the nuclear industry and had a disc of uranium

metal. The disc was 3 inches round and about ¾ inch thick. He said the disc was heavier than

lead and passed the disc around so we could see how heavy it was. Our teacher then took an old

metal file and struck the disc and sparks flew about 30 feet over the top of the students in our

class room. We had never seen anything make sparks like the uranium metal and a file. Being a

Boy Scout I was thinking what a great way to start a camp fire. When I was in the 11th grade our

chemistry teacher took us on a field trip to the yellow cake plant in Shiprock. The other

chemistry class was luckier and got to go to the yellow cake plant at the Durango Mill. We went

all through the entire plant processes and down most of the walkways. The bright yellow cake

powder was everywhere, including on our shoes and much of our clothing. Our teachers

believed and we were taught that uranium and nuclear energy was our friend and there was no

danger. I graduated from college in 1970 and accepted a position with the NM Dept. of Public

Health as a Health Scientist and moved back to Farmington, NM. In 1972, I was assigned the

task of cleanup and disposal of the Atomic Energy Commission’s (AEC’s) field lab. The

equipment and files were packaged up and sent to Santa Fe via a U-Haul truck.

I remember when they closed the Durango Smelter Mill site. The vegetation on Smelter

Mountain did not come back until after the Superfund cleanup. The smelter stack remained intact

until this cleanup. I specifically drove to Durango to take a photograph before it was toppled and

cleaned up. From 1986 to 1991, the U.S. Department of Energy removed tailings and other

contaminated materials, including the stack, from the mill site for the final cleanup.

Environmental Protection Agency (EPA) and Public Health Regulations History

Some of the dates of time are incorrect in my abstract and are corrected in this paper. The first

major chemical contaminants sampling of the Animas River was the “Survey of Interstate

Pollution of the Animas River Colorado-New Mexico 1959 Surveys” by the U.S. Public Health

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Service (PHS). Until 1954 there were not any environmental regulations to control the discharge

of radioactive waste into the environment. Procedures for the chemical analysis of water and

wastewater were just starting to be developed and were not adequately developed until the early

1970s. Earlier environmental and public health regulations were mainly concerned with

communicable diseases (typhoid fever, polio, etc.). Most of the environmental regulations and

the ability to enforce regulation came into fruition with the formation of the EPA in 1970. The

following are some of these milestones and environmental regulations:

General Mining Act of 1872 – An Act to promote the development of mining resources

on federal public lands. No cleanup or reclamation is required. The Act was never

changed.

Atomic Energy Act of 1954 –regulates the discharge of radioactive waste into the

environment.

US Environmental Protection Agency (EPA) formed in 1970 by an Executive Order of

Richard Nixon.

Occupational Safety & Health Agency (OSHA) was formed by the OSH Act of 1970 by

Congress.

Clean Air Act of 1970 to improve quality of the nation’s air. What is in the air eventually

ends up in the soil and water.

Federal Water Pollution Control Act of 1972 - (aka. Clean Water Act or CWA) to restore

and maintain the nation’s water.

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of

1972 – (a.k.a. Superfund) establishes a trust fund for cleaning up hazardous waste sites,

especially soil and water, and authorized federal action in cleanup (Superfund).

Safe Drinking Water Act of 1974 – established regulations and enforcement for drinking

water.

Resource Conservation and Recovery Act (RCRA) of 1976 – Requires a regulatory

system for the generation, treatment, transport, storage and disposal of hazardous wastes

(cradle to grave).

Clean Water Act of 1977 – Amends CWA to address toxic pollution control.

Uranium Mill Tailings Radiation Control Act of 1978 – Requires the cleanup of

radioactive contamination, including groundwater, from inactive processing sites.

Final Radionuclide’s Rule of 2000.

Groundwater Rule of 2007 (EPA) – developed to protect groundwater from

contamination (28).

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A Primer on Radioactivity and Its Environmental Regulations

Radioactivity is the spontaneous disintegration (decay) of an atom (element) with the emission of

radiation. The decay product of an atom is called a daughter or isotope (nuclide). Radiation is

the release radiant energy emitted in the form of waves (gamma ray or X-ray radiation) and/or

fast moving particles (alpha radiation particles and/or beta radiation particles). Alpha radiation is

heavy positively charged particles and travels about an inch in air and can be stopped by a piece

of paper. Beta radiation is a lighter negatively charged particle that can travel about 30 feet in

air, but can be stopped by 1/8 inch aluminum or ½ inch of Lucite (plastic). Gamma radiation is

true electromagnetic waves, but of a higher frequency than X-rays. Gamma rays are very

dangerous and several inches of lead or several feet of concrete are required for protection (27).

There are two general types of radioactive materials: Natural Occurring Radioactive Materials

(NORM) and manmade radioactive materials. Natural radioactivity is from certain elements that

have a high atomic number and are radioactive, such as uranium 235 & 238, radium 226 & 228,

thorium 232 and radon 222. Decay products of uranium are considered NORM. Artificial

radioactivity is manmade and its source is from nuclear weapons testing and atom smashing.

Strontium-90 and its decay products are manmade. Both NORM and manmade materials are

alpha and/or beta particle emitters. The danger from alpha and beta emitters is that they are

particles that can be ingested or inhaled. They are very damaging inside the human body (20).

What is Uranium? Uranium is a radioactive element, giving off small units of energy in the form

of particles and electromagnetic waves during a process of decay. The rate of decay varies for

each type of radioactive element and is measured in terms of “half-life”. Half-life means that at

the end of a specified time, half of a given amount of radioactive material will have changed to a

decay product. Uranium-238, with a half-life of 4.5 billion years, decays to thorium-234 by

alpha emissions. Each element of the decay series is called a daughter (isotope) product of

uranium-238. The decay pattern continues until Lead-206, a stable non-radioactive element is

reached. The decay pattern sequence is as follows: uranium 238, thorium 234, protactinium

234, Uranium 234, Thorium 230, Radium 226, Radon 222 (gas), Polonium 218, Lead 214,

bismuth 214, polonium 214, lead 210, bismuth 210, polonium 210, and lead 206 (stable form of

regular lead). Please remember that with each decay step some form of radiation is emitted (2).

The National Primary Drinking Water Standards or Maximum Contaminant Levels (MCLs) are

set for substances that are considered being of public health importance and pose a threat to

human health. There are five types of primary standards: inorganic contaminants, organic

contaminants, turbidity, microbial contaminants, and radiological contaminants. Radiological

contaminants include natural and manmade sources of radiation. Radiological Standards are

found in the “Code of Federal Regulations Reference: 40 CFR 141.24”. Radioactivity is the

only contaminant that has been shown to cause cancer for which standards have been set. Three

radioactive elements, radon, radium, and uranium, occur naturally in the ground and dissolve

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into groundwater supplies. The source of radioactive material in surface water is fallout from

nuclear testing and uranium mining activities. The MCLs for radiological contaminants are

divided into two categories: natural radioactivity that results from water passing through

deposits of naturally occurring radioactive materials (NORM) and manmade radioactivity such

as might result from industrial wastes, hospitals, research laboratories or testing of nuclear

explosives (bombs). Monitoring for natural radioactivity contamination is required every four

years for both surface water and groundwater community systems. There is not an MCL for

Radon, but EPA published a proposed regulation in 1999 of 300 pCi/L. Regulation of radon

continues to be a source of considerable debate (29). The final MCL has not been approved by

Congress (Lobbyist?) and has not been published. The following is the current monitoring

procedures and regulatory limits for drinking water (4).

Routine monitoring procedures to be as follows:

1. Test for gross alpha activity; if gross alpha exceeds 5 pCi/L then

2. Test for radium 226; if radium 226 exceeds 3 pCi/L, then

3. Test for radium 228.

4. The MCL for gross beta particle activity is 4 mrem/yr. (Surface water systems).

Maximum Contaminant Levels (MCLs) for Radioactivity

Constituent (Radionuclide’s) MCLs

Combined Radium 226 and

Radium 228

5 pCi/L (picocurie per

Liter)

Gross Alpha Activity (including

Radium 226 but excluding

Radon and Uranium

15 pCi/L (a measure of

radioactivity

Beta/Photon Emitters 4 mrem/yr.

Uranium 30 µg/L

Picocurie (pCi/L) is the quantity (unit of measure) of unstable or radioactive atoms decaying at a

rate of 3.7 X 10-2 disintegrations per second (dps). A rem (roentgen equivalent man) is a unit of

measure as a biological dose for radiation exposure to a man. It relates the effectiveness of the

different types of radiation in producing biological damage to the quantity of absorbed dose

which is measured as a rad (radiation absorbed dose). A rad is the measure of the energy

absorbed in any materials due to radiation exposure. An mrem/yr. (millirem) is 1/1000th of a rem

(20).

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Durango Mill Site History

The Durango Processing site (mill, smelter & chemical processing) is located in the southwestern

part of Durango, Colorado. The site is located on the west bank of the Animas River and

immediately southwest of the intersection of U.S. Highways 160 and 550. Lightener Creek was

used as the water supply for the site. This 120 acre site was the most valuable smelter mill site in

the San Juan Mountain Area. It had everything; an onsite coal supply for the furnace and

producing coke, a railroad for hauling and transporting supplies, water for ore processing,

electric power to run the equipment, a nearby limestone supply to use as a fluxing agent, a

nearby canyon for solids disposal and a river to dump into for liquid acid wastewater disposal.

Also, there was a copper processing site located 1/2 mile downstream with the same advantages.

From 1880 to closure in 1963 all process wastewater was dumped into the Animas River.

Contaminants continued to flow into the Animas River until the Superfund cleanup was

completed in 1991. The Mill Site operations can be divided into two general periods. The first

period (1880-1930) is the processing of metal ores from the Silverton area (includes La Plata

area) and the second period (1942-1963) is the processing of carnotite ores from the Uravan

mineral belt in southwestern Colorado. A brief timeline of these two periods follows (12).

Silverton Metal Ores Period (1880-1930)

1880 – The Greene & Co. Smelter was opened in Silverton in 1875 to process sulfide

lead-silver ores to metallic bullion. In 1880 the smelter was dismantled and moved to

Durango, where deposits of needed coal and limestone (for flux) were available.

1880 – City of Durango formed.

1881 – Lead processing Smelter operational.

1881 – First railroad line from Denver to Durango.

1882 – First railroad line from Silverton to Durango.

1899 – The Smelter Mill at this site became the American Smelting and Refining

Company (ASARCO) Smelter which was the regional smelter for lead, silver, zinc and

gold ores. A copper smelter mill was also built ½ downstream from this mill.

1915 – First train hauling zinc from Silverton area to Durango.

1930 – Smelter Mill closes operation (6).

The Silverton area is an old volcanic caldera (large crater). These igneous ores were typically

polymetallic containing the following metals: gold, silver, lead, copper, zinc, cadmium, iron,

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and other trace metals. However, most of Silverton ores were lead-silver sulfide ores. Lead-

silver sulfide ores could be easily reduced to metallic bullion and sulfuric acids. Sulfuric acids

were also used in the smeltering and recovery processes. An adjacent separate copper smelter

was built to process copper wastes from the smelting of the lead-silver ores. High grade gold

ores were typically melted in a smelter furnace and separated by gravity in the molten stage.

Lesser graded gold ore could be crushed, ground and amalgamated with mercury. After

amalgamation was complete, the mercury would be vaporized with heat and a gold nugget would

remain. In the later years a few Silverton area gold mines did use cyanide dissolution to recover

gold, but earlier extraction was with mercury amalgamation (30).

Ores were shipped by rail to the San Juan-New York smelter in Durango for processing. In 1899

it became the ASARCO Smelter. This became the regional smelter for lead-silver and quartz-

gold ores and concentrates until closure in 1930. The following metals and substances, that

affected human and animal health, could be found in the Silverton Metal Ores: aluminum,

antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, iron, lead,

magnesium, manganese, mercury, molybdenum, nickel, radium, selenium, silver, strontium,

thallium, thorium, uranium, vanadium, and zinc. Most of these were heavy or toxic metals. Not

all of these metals are on the EPA National Primary Drinking Water Standards. The metals on

the list are as follows: antimony, arsenic, barium, cadmium, chromium, copper, lead, mercury,

selenium, thallium and uranium. Cyanide is on the list, but is not present in the ore. It was later

used for extraction purposes. Many of the mine waste metals are not present because they are

not that common in drinking water. Industry practice at this time was to discharge process

wastes and tailings directly into a nearby creek or river. Most of us are aware of the dangers

from arsenic, lead and mercury poisoning. However, there are four others that are very toxic;

antimony, cadmium, chromium, and thallium. All are found in natural metal ore deposits and are

released into air and water as by-products from the refining of heavy metal sulfide ores. I

estimate toxic metal concentration discharges into the river at that time to have been in the

percentage ranges (1% = 10,000 mg/L) (3) (8).

Uravan Carnotite (Vanadium & Uranium) Ores Period (1942-1963)

1931 to 1941 – Durango Mill site was inactive, but still contaminating Animas River.

1942 to 1946 – The site was purchased by the Reconstruction Finance Corporation

(RFC), a government agency. Then, RFC sold and contracted U.S.Vanadium Corporation

(USV) for the recovery of vanadium from carnotite ores from SW Colorado. The

carnotite ore contained vanadium, uranium, and a trace of radium. Some vanadium was

produced, but the real goal was uranium for the war effort. Uranium recovery started

secretly in 1943 to produce uranium for the Manhattan Project and Los Alamos. This

plant started out recovering uranium from the vanadium mill tailings. The green sludge

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(slime) concentrate was shipped to Grand Junction where a secret uranium refinery

produced uranium concentrate (yellow cake).

1948 to 1963 – The U.S. Atomic Energy Commission bought the vanadium mill from

USV and leased it to the Vanadium Corporation of America (VCA) with an option to

buy. In 1953, VCA purchased the site. The site now processed carnotite uranium ore into

yellow cake for U.S. Government national defense programs (12).

1955 – George Moore, MD, MPH, Director of the San Juan Basin Health Department,

“discovered an enormous mound of radioactive tailing on the bank of the Animas River.

The VCA was processing uranium and dumping the waste material, still radioactive, into

the river for disposal. He asked his sanitarians to check the river downstream, as the

nearby city of Farmington, New Mexico, was drawing its drinking water from it. The

sanitarians brought back dead fish heavy with uranium ore. This was a huge

environmental problem that exceeded the purview of my health unit, so I contacted the

authorities in Washington, DC, for national attention. Within a week, the government

sent agents to the area to inspect the problem and then launched a program to correct it.

Still, my workers and I kept an eye on the Vanadium Corporation plant and soon

observed that the radioactive tailing were being given to the highway departments for

disposal on newly asphalted roads. Again we alerted the federal authorities to this

problem for correction” (10).

1958 – U.S. Public Health Service (PHS) began an intensive survey of pollution in the

Animas River that was from April 1958 to April 1959. The site processed uranium and

vanadium ore at a rate of 514 tons per day. PHS says the mill discharged dissolved

radium into the river and users in New Mexico were exposed to 7.6 mrem/yr. average

which is 1.9 times higher than the drinking water Maximum Contaminant Levels (MCLs)

of 4.0mrem/yr. The averages in Aztec were 3.4 and in Farmington were 2.8 for raw river

water. The Aztec and Farmington municipal drinking water treatment plants were not

able to remove the dissolved radium that was in their water (13).

1959 – VCA increases mill capacity from 514 to 700 tons of ore per day. This could

mean that the river was now getting 4.6 times the allowable amount of Radium. In

October, VCA promised to modify process treatment to reduce discharge of toxic

chemical waste. Barium sulfate and foam separation were even tried. However, this

increased process costs. Barium is very toxic (14) (16).

1963 – Removal of contaminants was not totally successful and the market value of

uranium crashed. With governmental pressure the Durango Mill site closed down and

operations moved to the Navajo Reservation in Shiprock, New Mexico.

1986 to 1991 – Superfund Cleanup was started and finished. Leaching and

contamination of alluvial groundwater beneath the mill tailing area was a concern.

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Radium, cadmium, molybdenum, uranium and selenium are the constituents of concern

in the mill tailings area groundwater. The principal potential health hazard of uranium

mine tailings is the emitting of small amounts of radon gas. “Radon is a colorless, inert,

radioactive gas formed by radioactive decay of radium, an element found in uranium

ore.” Mill tailings and other waste were transported to the Bodo Canyon Cell, which were

sealed containment structures located 1 ½ miles southwest of Durango in Ridges Basin.

The new Lake Nighthorse is also located in the Ridges Basin. Cleanup costs exceeded

$500 million (6). Cleanup cost were similar for the Shiprock cleanup.

2010 – The Durango Telegraph reports a federal government finding the containment cell

and other remediated areas may be leaking and possibly contaminating the River (11).

The ores used at the Durango Mill were carnotite ores. All of the carnotite ores processed at the

Durango Mill came from what is called the Uravan Mineral Belt in Southwestern Colorado.

Carnotite is a uranium and vanadium ore containing small amounts of radium. Uranium occurs

in very low concentrations of 0.1 to 2 percent in ore bodies. The average Uravan carnotite ore

was 0.29% uranium oxide and 1.6% vanadium oxide. This accounts for the large volumes of

waste generated during mining and milling. After processing over 99% of the ore remains as

mill tailings. These mill tailings still contain over 85% of the original radioactivity of the ore.

The production of uranium involves exploration, mining, and milling. The following is a list of

Uranium ores, but the Durango Mill processed mostly Carnotite (26):

Pitchblende – U3O8

Uraninite - UO2 (found with carnotite)

Carnotite – K2 (UO2)2(VO4)2. 3H20

Roscoelite - K(VAl)2 (OH)2AlSi3O10 (found with carnotite)

The basic conventional mill process steps are ore crushing and grinding, ore leaching, uranium

recovery from the leaching solution, and tailings disposal. After crushing and grinding to

achieve an even particle size the ore is mixed with water to form a half liquid, half solid slurry.

The ore slurry is pumped into an acid leaching system which is a series of tanks with agitators

designed to remove the uranium oxide from the ore rock. The leaching agent used for uranium

extraction depends upon the chemical properties of the ore, but it is typically sulfuric acid leach

solution. After the ore has been processed through the leach circuit, the loaded liquid must be

separated from the slimes and sand before entering the ion exchange or solvent extraction

systems. The separation is achieved through a series of filtration, washing, or classifier devices.

After the unwanted ore solids have been removed, ion exchange systems (resin or liquid) can

then be then used to concentrate the leached solution. Several stages of precipitation are needed

to complete the separation of the uranium oxide. The final stages of the milling processes

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include dewatering, drying, and packing of the uranium precipitate (yellowcake). This is the end

product and will contain approximately 96% uranium oxide which is sealed and shipped in 55

gallon steel drums (about 1000 pounds of yellowcake per drum) (23).

The Durango Smelter Mill made a number of process treatment changes from 1958 to 1959. The

reason for this change was to remove as much of the slimes (uranium oxide, vanadium oxide,

radium, etc.) as possible and reduce the amount of radioactive contaminants going into the river.

After the process change, the overall gross radioactivity discharged to the Animas River was

reduced by 75%. They started producing yellow cake around 1958 and quit shipping the green

sludge (slime) concentrate to Grand Junction. The waste products of the milling process were

the solid mine tailings and the liquid process liquors. Liquors were the solution portion of the

process containing the unwanted dissolved elements and spent acid leaching solution. The

current practice of most mill operations was to store the tailings in a pile and the acidic liquors in

above ground structures using earthen ponds to contain the solution. Most of the liquors, spent

process chemicals and other wastewater were eventually dumped into the river as the ponds

overflowed. The average liquid wastewater discharged to the Animas River was 340 gallons per

minute. The following is a list of chemicals used at the uranium mill each day in 1959 (13).

Chemicals Used Daily in Uranium Mill Process - 1959

Ammonium Sulfate 1640 Lbs/day

Sodium Hydroxide 600 Lbs/day

Sodium Chloride 25,800 Lbs/day

Soda Ash (Bulk) 46,200 Lbs/day

Soda Ash (Dense) 1,200 Lbs/day

Sodium Chlorate 450 Lbs/day

Sodium Peroxide 19 Lbs/day

Sulfuric Acid 83,900 Lbs/day

Potassium Permanganate 120 Lbs/day

Kerosene (liquid ion exchange) 260 Gallons/day

Other (extractants) 29 Gallons/day

When the ore is mined, Radon-222, an alpha-emitting radioactive gas, escapes into the air.

Radon causes lung cancer. Radon also is released from ore stockpiles, mine waste piles, vents,

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pit area, and mill tailings for thousands of years. Individuals living within about 4 km (2.5

miles) of the tailings piles are also at a greater risk because radiation standards cannot be met.

Mill tailings pose the greatest long-term hazard from mining and milling processes. Eighty-five

percent of the radioactivity in the original ore is still present in the tailings in the form of

unextracted uranium, radium, thorium and other trace metals. In the tailings, some other of these

radionuclide’s (isotopes) are found to be at 1000 times the normal levels in soils. Non-

radioactive contaminants which are commonly found in high levels in tailings include arsenic,

molybdenum, lead, and selenium. Selenium, molybdenum, and radium, have been found in high

concentrations in plant tissues around areas of uranium mining and milling. Radium, because of

its chemical similarity to calcium, tends to concentrate in bones and teeth of mammals. Humans,

consuming contaminated livestock will metabolize it in a similar fashion, increasing the chances

of leukemia and bone cancer (18). The following are some brief summaries and quotes from

selected articles in the “References” cited at the end of this paper.

Control of Radioactive Pollution of the Animas River – 1959 (14)

“Uranium is the parent, or first member, of a long series of radioactive isotopes found in nature.

It decays by successive alpha and beta emissions through 14 daughter elements to a non-

radioactive isotope of lead. All of the daughter elements, including thorium, polonium, radium,

bismuth, and others are found naturally along with the uranium. However, only the uranium is

wanted, and all of the remaining radioactive daughter elements are rejected as process wastes at

the refineries. These process wastes include wash waters and certain process liquors, as well as

the sands and waste ore solids that have been stripped of their uranium”.

“Radium is the most hazardous radioelement contained in uranium mill wastes. Its maximum

permissible concentration in drinking water is exceedingly small and its ingestion in water or in

contaminated food or milk is regarded as quite dangerous”. Radium is a long-lived alpha emitter

that deposits in the bones. “Hence, uranium mill waste discharges to a stream may seriously

interfere with such water uses as domestic supply, crop irrigation, and stock watering. In

addition, the discharge of toxic chemicals can inhibit or destroy aquatic life, thereby depriving

downstream populations of the recreational use of the stream. As will be seen, waste discharges

from the Durango, Colorado, uranium mill contained sufficient radium and toxic chemicals to

interfere seriously with the downstream use of the Animas River”.

In 1950, a brief survey was performed above (upstream) and below (downstream) the Durango

Mill on the Animas River. At a flow of 220 cfs, the dissolved radium above the mill was 0.2

pCi/L and below the mill was 4.5 pCi/L. In 1955, a second brief survey was performed at a flow

of 220 cfs and the dissolved radium above the mill was again 0.2 pCi/L and below the mill was

3.3pCi/L. The two effluents from the mill contained 76 and 25 pCi/L of dissolved radium. The

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gross alpha activity of suspended solids in the main effluent was 33,200 pCi/L. “The aquatic

biota samples of 1955 indicated some concentration of radium by algae and insects, the

downstream samples having 60 to 110 times the radium content of those from above the mill”.

A conference was held on April of 1958 and the Public Health Service was directed to carry out

a one-year fact finding survey having the following objectives:

1. Evaluate the internal radiation exposure to radium and strontium-90 in the Durango-

Farmington pollution area, and the portion of this total exposure that resulted from

radium and other waste discharges from the uranium refinery.

2. On the basis of the above evaluation and other tests, assess the interstate pollutional

aspects of the uranium refinery waste discharges.

From this conference, the 1959 Survey of Interstate Pollution of the Animas River Colorado-

New Mexico was developed. The Survey was very extensive. Samples were collected 3 miles

upstream and almost 60 miles downstream from the mill site. All samples were delivered

initially to the Atomic Energy Commission (AEC) field laboratory in Farmington, New Mexico.

The building was built and furnished by the San Juan County Health Department. The samples

were screened at the field laboratory and samples were prepared for subsequent analysis at the

Cincinnati or Salt Lake City Laboratories of the Public Health Service. “Gross radio-assay of

selected samples of all types was performed at the field laboratory in order to provide immediate

information as to the progress of the survey and the relative importance of types of samples.”

Some of these results are as follows. Two miles downstream of the mill site the river water

average radioactivity was as follows: gross alpha – 120 pCi/L, gross beta – 170 pCi/L and

dissolved radium – 12.6 pCi/L. The river muds (sediment) were as follows: gross alpha – 1,250

pCi/L, gross beta – 1,350 pCi/L, and total radium – 171pCi/L. The radioactivity in algae was as

follows: gross alpha – 3900 pCi/L, gross beta – 5,760 pCi/L, and total radium – 880 pCi/L.

Finally, the radioactivity in insects was gross alpha – 1820 pCi/L, gross beta – 4110 pCi/L and

total radium – 71 pCi/L. Needless to say, there were no fish available for sampling.

“In summary, then, it appears that the only acceptable course in the area of radioactive waste

control is to keep all radioactive effluent discharges to the environment to a minimum, as has

been the advice of the National Committee on Radiation Protection (14).”

Estimating Human Radiation Exposure on the Animas River – 1960 (15)

“Radioactive materials such as radium and radiostrontium may be ingested in a number of ways,

of which the drinking of water constitutes only one. The chemical and metabolic characteristics

of these radioactive materials resemble those of calcium. On ingestion, these materials find their

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way to the human skeleton. While in the bones, they undergo radioactive decay, and the alpha,

beta, and gamma radiations that are emitted bombard the surrounding tissue. It is these

radiations that must be minimized. In this regard, the radium or radiostrontium may be ingested

by way of water, milk, or food. In estimating the radiation dose, it is important to learn how

much may be ingested from each of these; the total amount of radioactive material ingested will

be the sum of those portions ingested by each route. It is the total quantity ingested daily that is

of importance, rather than the concentration in water or, for that matter, in milk or any particular

good product.” The bone-seekers, radium 226 and strontium 90 are classed as relatively

hazardous materials in terms of the concentrations that may occur in water. Hence, the

minimization of radiation exposure involved is essentially the reduction of radium 226 released

from the uranium mill. Dissolved radium 226 is the primary pollutant in the river environment

and in local drinking water treatment plants.

The upgrade and increase of capacity of the uranium mill between the summer of 1958 and

spring of 1959 decreased the discharge of most radioactive materials to the river. However, the

Dissolved radium 226 concentration, at 2 miles below the mill increased from 12.6 pCi/L to 24

pCi/L. The regulatory limit at that time was 3.3 pCi/L. The current regulatory limit for Radium

226 and 228 is 5.0 pCi/L. Again, the report found that a conventional drinking water treatment

plant does not remove dissolved radium. “The Animas River report (1959 Survey of Interstate

Pollution of the Animas River Colorado-New Mexico) was rather voluminous, and its

distribution was limited. A total of 300 copies were distributed to various federal, state, and

local agencies and to individuals requesting them (15)”.

Research for the Control of Radioactive Pollutants – 1963 (17)

“The primary goal of this research was the detection, surveillance, and control of radioactive

water pollution. By far the most significant feature of the field and laboratory research on

uranium mill wastes discharges has been the identification of the tailings solids as the primary

source of general environmental contamination with radium 226”. “While in 1956, dissolved

radium 226 concentrations as high as 88 pCi/L were found in the waters of the Animas Basin, the

highest levels now observed (1962) are below 3.0pCi/L which is a generally accepted limit”.

“Earlier concentrations of radium 226 in river sediments have ranged as high as 2,100 pCi/g,

whereas last year’s data (1962) showed most results at or near the natural level of less than 2.0

pCi/g” (17).

Conclusion

In summary, the Durango Mill site polluted and contaminated the Animas River with very

concentrated toxic substances for over 100 years. These substances consisted of many toxic

heavy metals, radioactive materials, plant process tailings and wastewater process solutions.

Page 14 of 16

However, the most damaging was radium, both dissolved and suspended. These toxic substances

were concentrated by the algae in the river and traveled up the food chain killing most insects

and fish. Further damage was done to people and agriculture (crops and animals). Many of

these substances are still in the river sediment. With the 1963 closure of the Durango Mill site

and the 1991 completed Superfund cleanup, the site is of very little threat to the environment.

Our greatest concern now should be the cleanup of the numerous abandoned mines in the

Animas River Watershed.

REFERENCES

1. Long-Term Monitoring Plan, Official Draft, New Mexico Environment Department,

October 20, 2015.

2. Uranium Mining & Milling: A Primer, David Riccitiello and et.al., The Workbook, Vol.

IV, nos. 66-7, November/December 1979.

3. Integrated Investigations of Environmental Effects of Historical Mining in the Animas

River Watershed, San Juan County, Colorado Chapter B and Chapter C, Church, S.E.,

von Guerard, Paul, and Susan E. Finger eds., U.S. Geological Survey Professional Paper

1651, http://pubs.usgs.gov/pp/1651/, 2007.

4. Water Treatment Plant Operation, Volume II, 6th Edition, California State University

Sacramento, Office of Water Programs, 2015.

5. Standard Methods for the Examination of Water and Wastewater (14th Edition),

American Public Health Association, New York, N.Y. 1976.

6. Durango, Colorado, Processing and Disposal Sites – Fact Sheet, USDOE Legacy

Management, UMTRCA Title I, 01/31/2015,

www.1m.doe.gov/durango/disposal/sites.aspx

7. Government Wins Pollution Test: Vanadium Corp. of America takes steps to clean up

radioactive wastes at Durango, Colo. uranium mill, Chemical & Engineering News, July

27, 1959.

8. Source, Transport, and Partitioning of Metals between Water, Colloids, and Bed

Sediments of the Animas River, Colorado, S.E. Church, B.A. Kimball, D.L. Fey, D.A.

Ferderer, T.J. Yager, and R.B. Vaughn, U.S. Geological Survey Open-file Report 97-

0151, http://pubs.usgs.gov/of/1997/ofr-97-0151 .

9. Metals from the Smelter Sites South of Durango, http://pubs.usgs.gov/of/1997/ofr-97-

0151/html/stpmw13.shtml#Metals_from_the_Smelter_Sites, 1996.

Page 15 of 16

10. Public Health Initiatives in the Four Corners of Colorado, 1955-1957, George Moore

and Berwyn Moore, Public Health Reports, May-June 2008, Volume 123,

www.publichealthreports.org.

11. A New Hot spot – Department of Energy Reports Possible Uranium Leakage, The

Durango Telegraph, February 25, 2010. www.durangotelegraph.com

12. Earlier history of the Durango Site by William L. Chenoweth, September 2006, M008

Durango, CO uranium mill tailing removal collection, Center of Southwest Studies, Fort

Lewis College, Durango, CO., 2006.

13. Survey of Interstate Pollution of the Animas River (Colorado-New Mexico) II. 1959

Surveys, E.C. Tsivoglou and et.al, U.S. Dept. of HEW, Public Health Service, January

1960.

14. Control of Radioactive Pollution of the Animas River, E.C. Tsivoglou, M. Stein, and

W.W. Towne, Journal (Water Pollution Control Federation), Vol. 32, No. 3, Part I

(March, 1969).

15. Estimating Human Radiation Exposure on the Animas River, Tsivoglou, Ernest C,

Sharer, S. David, Jr., Jones, John D., Clark, Don A., Journal – American Water Works

Association, Volume 52, Number 10, October 1960.

16. Radium Removal from Uranium Mill Wastewater, Herbert M. Schoen, Eliezer Rubin, and

Dipen Ghosh, Journal of the Water Pollution Control Federation, Vol. 34, No 10,

October 1962.

17. Research for the Control of Radioactive Pollutants, E.C. Tsivoglou, Journal (Water

Pollution Control Federation), Vol. 35, No. 2 (Feb., 1963).

18. A Description of Radiological Problems at Inactive Uranium Mill Sites and Formerly

Utilized MED/AEC Sites, D.G. Jacobs and H.W. Dickson, Oak Ridge National

Laboratory , ORNL/OEPA-6, February, 1979.

19. Radioactivity in Waters and Sediments of the Colorado River Basin, 1950-1963, D.T.

Wruble, S.D. Shearer, D. E. Rushing, and C.E. Sponagle,, Rad. Health Data 5(11, 557-

567, 1964.

20. Basics of Industrial Hygiene, Debra Nims, John Wiley & Sons, Inc., NY, NY, 1999.

21. Treatment of Metal Wastestreams, 4th Ed., California State University Sacramento, Office

of Water Programs, 2013.

Page 16 of 16

22. Standard Practices for the Measurement of Radioactivity (D 3648 – 78), 1979 Annual

Book of ASTM Standards – Part 31 Water, American society for Testing and Materials,

1079, Philadelphia, Pa.

23. Uranium Mining and Processing – Nuclear Operations Near Grants, N.M., Kerr-McGee

Corporation, 2nd Printing, Kerr-McGee Litho P-739-7M

24. Production of Yellow Cake and Uranium Fluorides, Proceedings of Advisory Group

Meeting, Paris, 5-8 June 1979, International Atomic Energy Agency, Vienna, 1980

25. CRC Handbook of Chemistry and Physics (College Edition), 46th Ed., Robert C. Weast

(Editor), The Chemical Rubber Co., Cleveland, Ohio, 1965-1966.

26. Geology of the Uravan Mineral Belt, Geological Survey Bulletin 988-A, R.P. Fischer and

L.S. Hillpert, United States Government Printing Office, Washington, D.C., 1952.

27. Chemical Technicians’ Ready Reference Handbook, G.J. Shugar, R.A. Shugar, Lawrence

Bauman, and Rose Shugar Bauman, McGraw Hill Book Co., NY, 1981.

28. U.S. EPA Website, www.epa.gov, May 2016.

29. Environmental Engineering, 5th Ed., Salvanto, Joseph A., Nelsen L. Nemerow and

Franklin J. Agardy, John Wiley & Sons, 2003.

30. Environmental Effects of Historical Mining in the Animas River Watershed, Southwestern

Colorado, USGS, 2007. http://pubs.usgs.gov/fs/2007/3051

There is much information and raw data available in the Survey of Interstate Pollution of

the Animas River (Colorado-New Mexico) Part I (1958) and Part II (1959), E.C.

Tsivoglou and et.al, U.S. Dept. of HEW, Public Health Service, January 1960. I was

only able to obtain a small section of Part II. This “report was rather voluminous and its

distribution was limited. A total of 300 copies were distributed to various federal, state,

and local agencies and to individuals requesting them”. A complete copy of these reports

should be obtained and given to Fort Lewis College, San Juan College, University of

NM, NM Tech, and NMSU (both college and WRRI libraries).

If you have any questions, comments, or need help locating the above references, please

contact me at: Norman Norvelle, P.O. Box 31, Farmington, NM 87499,

norvellehome@msn.com , Mobile (505) 330-4213