The Stoker Company is a producer and applier of pesticides and a crop dusting loading facility, located in Imperial County, California, approximately 25 miles from the Mexican border. It is currently listed as a Superfund site because pesticides developed and used there are considered a human health hazard due to long-term exposure that may cause adverse health effects. Beginning in 1966, operations have caused on-site and off-site pesticide contamination to surface soil, water, and air.
Stoker Company has supplied and applied pesticides since May 26, 1966. [1] The Stoker Company sells, stores and applies pesticides using aircraft and ground equipment over a 26-acre site. Runoff from the cleaning of aircraft goes to underground concrete sumps located under each wash rack. Approximately once a week, the pesticide waters are pumped from the sumps into a mobile spray rig and sprayed onto a 15–20-acre plot on the Stoker site consisting of a dirt road leading to the airstrip. [2] During the 1960s and 1970s, Stoker released approximately 300 gallons of waste water per day, but the California Regional Water Quality Control Board recently estimated that this was reduced to 100 gallons. [1] [3] The wash water has been determined to be non-hazardous.
On May 9, 1988, a pond located at a nearby residence near the site suffered a fish and bird kill. [2] Numerous dead fish (shad and catfish) and ten dead birds (Snowy Egrets) were found around the perimeter of the pond. [2] Upon necropsy, the California Department of Fish and Game (CDFG) determined the fish tissue was contaminated by high levels of several different pesticides. [1] The CDFG analyzed the pond and concluded that high winds blew pesticides from the Stoker airplane cleaning activities into the pond. [2] After the discovery of dead birds and fish, the pond was closed to public activities due to the belief of contamination. Later in 1988, an on-site warehouse that contained pesticide supplies caught fire and burned to the ground. [1] The fire started in the east end of the warehouse where sulfur and diatomaceous clays were stored. [2] To avoid health risks, businesses and residences within a 2-mile radius were evacuated. During the fire, approximately 300 tons of soil were contaminated and later disposed of in a landfill regulated under the Resource Conservation and Recovery Act (RCRA). [1]
Throughout 1988 to 1989, the United States Environmental Protection Agency (EPA) investigations found numerous pesticides in on-site soil, the nearby canal and pond, and air measurements. [1] [3] Later in 1989, Stoker submitted a closure plan for the land treatment unit. Stoker later reconsidered these actions and still continues to spray wash waters on-site. [3] In July 1991, EPA placed the Stoker Company site on the National Priorities List of hazardous waste sites after testing showed that the disposal of pesticides on-site was contaminating on-site surface soil, which was then being relocated to off-site air, soil, and surface water. [2] In 1993, the EPA reevaluated the site and determined that they did not need to perform further actions during that time.
Agricultural pesticide use near populated areas is increasing worldwide due to population growth into formerly rural farmland. [4] The Stoker Company is located on 26 acres of barren land with no vegetation. Some of the contaminated soil has blown off-site and affected nearby surface soil and surface water.
Twenty different pesticides were detected in on-site soil surface samples including diazinon, endosulfan and heptachlor epoxide, which were found at highest levels in the burn area, and disulfoton, endosulfan, merphos, and methamidophos which were found in high concentrations near the former warehouse and office. The concentrations of listed pesticides were all significantly above comparison values and therefore of concern for human and environmental health. On-site groundwater was reported to contain low levels of butyric acid, dinoseb, and endosulfan due to leaching. Only endosulfan concentrations were significantly above comparison values. On-site air analyses also found eight different pesticides at levels significantly above background levels. The eight pesticides were dacthal, diainon, endosulfan, malathion, mevinphos, maled, methyl parathion, and phorate. However, these concentrations were not enough in comparison to raise concern. Lastly, dead fish samples found in the pond contained dacthal (27.3 mg/kg), DDE (0.11 mg/kg), diazinon (0.1 mg/kg), and endosulfan (0.92 mg/kg). [2]
There is increasing public concern regarding the health risks associated with residential exposure to agricultural pesticides, but limited understanding about the potential for such exposures. [4] Pesticides are toxic chemicals and can therefore pose a threat to humans from inadvertent exposure. [2] After the evaluation by the EPA, the momentum that brought the Stoker site to the federal government soon decreased once there was a lack of evidence that directly connected the company to major widespread environmental and health impacts. [5]
The impacted populations include on-site workers, the family formerly living on the neighboring D&K property, the D&K Duck Hunting members, individuals using untreated water, and individuals living near the crop dusting operations. Approximately 130 people live within 1 mile of the site, 400 people work in five neighboring businesses, and 45 workers are employed by Stoker Company. [1] Four residences are located within one mile of the site, with the nearest family living one-half mile from Stoker Company. From 1983 to 1989, a family lived in a mobile home on the D&K property, which is around 80 feet from Stoker.
Long term exposure to the contaminants through incidental ingestion and skin absorption at the Stoker site may cause non-cancer adverse effects. [2] However, the ingestion of contaminated fish is not thought to have resulted in significant risk of developing cancer. D&K club members have not reported apparent health hazards due to the ingestion of contaminated fish or incidental ingestion. Additionally, other individuals who may have drunk the water or lived near the crop dusting operations do not seem to be showing health impacts. However, it is not possible to evaluate the risks from periodic or long-term exposure from pesticide spray drift from Stoker airplanes due to lack of information. Furthermore, there is a large body of unknown information due to the absence of monitoring data. [2]
The EPA identified three different sources for contamination: 1) the land disposal of rinse water; 2) the burn area at the southern end of the airstrip; 3) the warehouse fire of 1988. The residents living in the mobile home on the D&K property reported a variety of symptoms experienced by the family members. However, the actual health effects that are occurring are unknown due to lack of knowledge of exposure levels. Additionally, the Toxic Chemical Release Inventory contains no record of environmental releases from any industrial facility in Imperial, including Stoker Company. [2] Overall, it is not possible to assess the risks and implications of the effects of contaminants in areas located around the Stoker Company.
The Carson River is a northwestern Nevada river that empties into the Carson Sink, an endorheic basin. The main stem of the river is 131 miles (211 km) long although the addition of the East Fork makes the total length 205 miles (330 km), traversing five counties: Alpine County in California and Douglas, Storey, Lyon, and Churchill Counties in Nevada, as well as the Consolidated Municipality of Carson City, Nevada. The river is named for Kit Carson, who guided John C. Frémont's expedition westward up the Carson Valley and across Carson Pass in winter, 1844. The river made the National Priorities List (NPL) on October 30, 1990 as the Carson River Mercury Superfund site (CRMS) due to investigations that showed trace amounts of mercury in the wildlife and watershed sediments.
Dicofol is an organochlorine pesticide that is chemically related to DDT. Dicofol is a miticide that is very effective against spider mite.
Pentachlorophenol (PCP) is an organochlorine compound used as a pesticide and a disinfectant. First produced in the 1930s, it is marketed under many trade names. It can be found as pure PCP, or as the sodium salt of PCP, the latter of which dissolves easily in water. It can be biodegraded by some bacteria, including Sphingobium chlorophenolicum.
Toxaphene was an insecticide used primarily for cotton in the southern United States during the late 1960s and 1970s. Toxaphene is a mixture of over 670 different chemicals and is produced by reacting chlorine gas with camphene. It can be most commonly found as a yellow to amber waxy solid.
Endosulfan is an off-patent organochlorine insecticide and acaricide that is being phased out globally. It became a highly controversial agrichemical due to its acute toxicity, potential for bioaccumulation, and role as an endocrine disruptor. Because of its threats to human health and the environment, a global ban on the manufacture and use of endosulfan was negotiated under the Stockholm Convention in April 2011. The ban has taken effect in mid-2012, with certain uses exempted for five additional years. More than 80 countries, including the European Union, Australia, New Zealand, several West African nations, the United States, Brazil, and Canada had already banned it or announced phase-outs by the time the Stockholm Convention ban was agreed upon. It is still used extensively in India, China despite laws banning it, and few other countries. It is produced by Makhteshim Agan and several manufacturers in India and China. Although, the Supreme Court had, by an order dated 13.05.2011, put a ban on the production and sale of endosulfan in India till further orders.
Endrin is an organochloride with the chemical formula C12H8Cl6O that was first produced in 1950 by Shell and Velsicol Chemical Corporation. It was primarily used as an insecticide, as well as a rodenticide and piscicide. It is a colourless, odorless solid, although commercial samples are often off-white. Endrin was manufactured as an emulsifiable solution known commercially as Endrex. The compound became infamous as a persistent organic pollutant and for this reason it is banned in many countries.
Soil contamination, soil pollution, or land pollution as a part of land degradation is caused by the presence of xenobiotic (human-made) chemicals or other alteration in the natural soil environment. It is typically caused by industrial activity, agricultural chemicals or improper disposal of waste. The most common chemicals involved are petroleum hydrocarbons, polynuclear aromatic hydrocarbons, solvents, pesticides, lead, and other heavy metals. Contamination is correlated with the degree of industrialization and intensity of chemical substance. The concern over soil contamination stems primarily from health risks, from direct contact with the contaminated soil, vapour from the contaminants, or from secondary contamination of water supplies within and underlying the soil. Mapping of contaminated soil sites and the resulting cleanups are time-consuming and expensive tasks, and require expertise in geology, hydrology, chemistry, computer modeling, and GIS in Environmental Contamination, as well as an appreciation of the history of industrial chemistry.
Methoxychlor is a synthetic organochloride insecticide, now obsolete.
AMCO Chemical was a chemical distribution company located in Oakland, California. The land the company operated on is designated as a U.S. Environmental Protection Agency (EPA) Superfund cleanup site.
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The Waste Disposal Inc. Superfund site is an oil-related contaminated site in the highly industrialized city of Santa Fe Springs in Los Angeles County, California. It is approximately 38 acres (15 ha), with St Paul's high school immediately adjacent to the northeast corner of the site. Approximately 15,000 residents of Santa Fe Springs obtain drinking water from wells within three miles (4.8 km) of the site.
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