V ADDITIONAL DETECTED CONTAMINANTS: TOXICITY PROFILES

Transcription

1 Appendix V ADDITIONAL DETECTED CONTAMINANTS: TOXICITY PROFILES The following chemicals were found above detection limits on the Proposed Strecker Forest Development Site. The detected levels of these chemicals fell below their respective MRBCA, PRG, or MCL. VOCs and SVOCs found above detection limits in soil only: 2-Methylphenol, also known as o-cresol, evaporates slowly from soil and water but can be degraded by bacteria quickly. Since it is a corrosive substance, breathing, ingesting or touching it at high levels can cause harm. Inhalation at high levels results in irritation of the eyes, nose and throat. Ingestion at high levels can cause mouth and throat burns, stomach pain, vomiting, kidney problems, and effects on the blood and nervous system. Skin contact can burn the skin and damage the kidneys, liver, blood, lungs, and brain. Inhalation and skin contact may cause death. The EPA determined that 2- methylphenol is a possible human carcinogen. No studies exist on the effects of 2- methylphenol on children. However, a baby, who accidentally had a solution of cresol spilled on his head, suffered damage to the skin, liver, and kidneys, became comatose and died within 4 hours. OSHA has established a permissible exposure limit of 5ppm for cresols in the air (ATSDR 2009a). Isopropylbenzene, also known as cumene, is a colorless liquid with a sharp odor. Exposure may occur through inhalation, ingestion, skin absorption, skin and/or eye contact. Exposure may cause skin and eye irritation, headaches, dermatitis, narcosis, and coma. OSHA has established permissible exposure limits as 50 parts per million for an 8-hour day, 40-hour workweek (CDC 2009). n-butylbenzene is a colorless, flammable liquid. This chemical is mildly toxic when ingested, and it is incompatible with oxidizing materials (Lewis 2008). n-propylbenzene, also known as isocumene, is a clear, flammable liquid that is insoluble in water. It is a dangerous fire hazard and mildly toxic when ingested (Lewis 2008). o-xylene is an isomer of xylene and is highly flammable. It is a colorless liquid which is sweet smelling and naturally occurs in petroleum and coal tar. o-xylene is widely used in leather, printing and rubber industries as a solvent. Exposure may cause developmental affects and negatively impact the liver, nervous system, and renal system. Exposure can also cause irritation of the eyes, nose, throat, and skin. Exposure may also cause dizziness, reduced muscle coordination and even death. The

2 limit for drinking water is 10 parts per million and for air in the workplace it is 100 parts per million for an 8-hour day,40-hour workweek (ATSDR 2009a). p-isopropyltoluene, also known as p-cymene, is an odorless and colorless to paleyellow liquid. This chemical is flammable and mildly toxic. Exposure may cause skin irritation and negative effects on the central nervous system (Lewis 2008). VOCs and SVOCs found above detection limits in soil only: 1,2,4-Trichlorobenzene is an volatile organic compound derived from benzene. Studies have shown that exposure to 1,2,4-trichlorobenzene can lead to an increase in adrenal gland weights. According to the EPA it is not considered to be carcinogenic. The EPA has set a reference dose of 1x10-2 mg/kg/day (US EPA 2010). 1,2-Dichlorobenzene ranges from colorless to pale-yellow, has a pleasant smell, and is poorly soluble in water. Exposure may occur through inhalation, skin absorption, ingestion, skin and/or eye contact. Exposure to high levels may cause eye and nose irritation, upset stomach, skin blisters, difficulty breathing, and liver and/or kidney damage (CDC 2009). The EPA has set a reference dose at 9x ,2- dichlorobenzene is not classified as a human carcinogen (US EPA 2010). 2,4,5-Trichlorophenol exists in crystal form and has been shown to cause adverse effects to the liver and kidneys. The EPA has not assessed the carcinogenic risk of this substance but placed a reference dose at 1x10-1 mg/kg/day (US EPA 2010). 4-Methylphenol, also known as p-cresol, has similar properties and health effects to 2- methylphenol, or o-cresol. In addition to the health effects described for 2- Methylphenol, studies on animals have found lesions inside the nose and thyroid gland damageafter ingesting food containing 4-methylphenol. The EPA classifies 4- methylphenol as a possible human carcinogen. OSHA has set a limit of 5parts per million of methylphenols in the air to protect workers for 8-hour day, 40-hour workweeks (ATSDR 2009a). Acenaphthene is a polycyclic aromatic hydrocarbon (PAH). It is known to cause hepatotoxicity, and the EPA has set a reference dose at 6x10-2 mg/kg/day. It has not been assessed for its carcinogenicity by the EPA (US EPA 2010). Benzo(a)pyrene is a PAH that is a black or brown amorphous residue. Acute exposure can lead to skin rash or eye irritation with a burning sensation. Chronic exposure can lead to a loss of color and reddish areas on the skin, thinning of the skin, warts, and

3 bronchitis (NIOSH 2009).Benzo(a)pyrene is classified by the EPA as a probable human carcinogen and the IARC as a group 1 carcinogen based on sufficient animal studies (US EPA 2010). Benzo(b)fluoranthene is a PAH. According to the EPA it is a probable human carcinogen based on animal studies (US EPA 2010). The OSHA permissible exposure limit is set at 0.2 mg per cubic meter for an 8-hour day, 40-hour workweek (OSHA 2010). Benzo(ghi)perylene is a PAH. The EPA has not classified this substance as a human carcinogen (US EPA 2010). Other data about human health effects are insufficient. Bis(2-Ethylhexyl)phthalate, also known as DHEP, does not evaporate or dissolve in water easily. Because it occurs at such low levels in the environment, it is not likely to cause health effects in humans. Also, it is not easily taken up through the skin. Animal studies have shown that high exposures of DEHP can cause reproductive effects and damage to the liver. Based on animal studies, the Department of Health and Human Services (DHHS) and the EPA have classified DEHP as a probable human carcinogen. However, the International Agency for Research on Cancer (IARC) has stated that DEHP cannot be classified as a human carcinogen. The EPA limits the amount of DEHP in drinking water to 6 parts per billion. OSHA set a maximum average of 5 mg per cubic meter of air in the workplace for an 8-hour day, 40-hour workday (ATSDR 2009a). Bromomethane is a colorless gas that has a noticeable odor at very high concentrations. Bromomethane breaks down slowly in the environment. Inhalation exposure may cause headaches, weakness, and nausea. Inhalation of large amounts may lead to a build-up of fluid in the lungs and cause breathing difficulties. Exposure could also possibly cause muscle tremors, seizures, kidney damage, nerve damage, and death at very high levels (1,600-60,000 parts per million). Ingestion of bromomethane can cause stomach irritation and direct contact can cause itching, redness and blisters. The EPA has determined that bromomethane is not a human carcinogen. The FDA limits the amount of bromomethane in the food to parts per million. OSHA limits the average level of bromomethane in the workplace air to 20 parts per million for an 8-hour day, 40-hour workweek (ATSDR 2009a). Chrysene is a PAH that the EPA has classified as a probable human carcinogen based on significant animal studies. The complete health effects of chrysene have not been studied (US EPA 2010).

4 Dibenzo(a,h)anthracene is a PAH that the EPA has classified as a probable human carcinogen based on significant animal studies (US EPA 2010). Fluoranthene is a colorless solid that is poisonous through intravenous exposure. Fluoranthene is moderately toxic through ingestion and dermal contact. This chemical is a questionable carcinogen and combustible when exposed to fire (Lewis 2008). Fluorene is a colorless solid and a PAH. Fluorene causes a decrease in red blood cells and packed cell volume and hemoglobin in animal studies. The EPA and OSHA has not classified fluorene as a human carcinogen and set the reference dose to 0.04 mg/kg/day (US EPA 2010). Methylene chloride is a colorless liquid with a mild, sweet odor. Exposure to methylene chloride commonly occurs by breathing contaminated air or touching the chemical. Large amounts of inhalation exposure may cause dizziness, nausea, and/or numbness in fingers and toes. Smaller amounts of inhalation exposure may affect hand-eye coordination. Skin contact with the chemical may cause burning and redness. The chemical does not occur naturally, and it is commonly used as a paint stripper and for other industrial purposes. It is not clear that methylene chloride causes cancer in humans. OHSA has established permissible exposure limits of 25 parts per million of methylene chloride in workplace air for 8-hour day, 40-hour workweek (ASTDR 2009a). Phenanthrene exists as a colorless solid or as monoclinic crystals. The chemical is poisonous when intravenous exposure occurs. Phenanthrene is moderately toxic through ingestion and dermal contact. This chemical is a questionable carcinogen, combustible when exposed to fire, and can react with oxidizing materials (Lewis 2008). Phenol is a colorless to light-pink crystalline solid. Following large and repeated releases, phenol can remain in the air, water, and soil for long periods of time. Acute exposure to phenol can cause respiratory irritation, headaches, and burning eyes. Direct contact with the skin to high amounts of phenol can cause skin burns, liver damage, dark urine, irregular heartbeat, and in some cases death. Ingestion of high doses has resulted in burns and death. Animal studies have shown that chronic exposure to high doses of phenol can cause paralysis and injury to the heart, liver, kidneys, and lungs, and in some cases death. The IARC and the EPA have not classified phenol as a human carcinogen. The EPA has limited the amount of phenol in drinking water to 2 mg/l for a lifetime exposure. OSHA has set a limit of 5 parts per million of phenol in the air for 8-hour day, 40-hour workweek (ATSDR 2009a).

5 Pyrene is a black or dark-brown amorphous residue. Pyrene is a PAH that has been shown to cause kidney effects such as renal tubular pathology and decreased kidney weights in animals. The EPA has not classified pyrene as a possible human carcinogen based on animal studies. The EPA has set a reference dose for pyrene at 0.03 mg/kg/day (US EPA 2010). Sec-butylbenzene is a colorless, flammable liquid. The chemical is moderately toxic when ingested, and it may cause irritation if dermal or eye contact occurs. Secbutylbenzene is incompatible with oxidizing materials (Lewis 2008). Trichlorofluoromethane is commonly used as an industrial solvent and refrigerant. Exposure may occur through inhalation, ingestion, dermal and/or eye contact. Incoordination, dermatitis, asphyxia, cardiac arrest, liquid frostbite, tremors, and cardiac arrhythmias may result from exposure. OSHA limits the average level of trichlorofluoromethane in the workplace air to 1000 parts per million for an 8-hour day, 40-hour workweek (CDC 2009). VOCs and SVOCs found above detection limits in groundwater only: 1,1,1-Trichloroethane is an organic compound that does not occur naturally in the environment. It can travel in the air for years and get broken down by the sunlight. Microorganisms can also break down 1,1,1-trichloroethane. Acute inhalation can lead to dizziness, lightheadedness, and loss of coordination. Inhalation of 1,1,1- trichloroethane at higher levels can cause unconsciousness, blood pressure decrease, and arrhythmia or even the heart to stop beating. Chronic inhalation effects are unknown. Animal studies have shown that inhaling high levels of 1,1,1-trichlroethane can damage the breathing passages, cause mild effects in the liver, and affect the nervous system. Ingestion of large amounts has caused effects on the nervous system, mild liver damage, unconsciousness, and death in animals. Direct contact with the skin can cause irritation. Repeated exposure to the skin might affect the liver and at large amounts cause death. The IARC and the EPA have determined that 1,1,1- trichloroethane is not classifiable as a human carcinogen. The EPA limits the levels of this substance in drinking water to 0.2 parts per million. The OSHA limits the amount of 1,1,1-trichloroethane in the workplace air to 350 parts per million (ATSDR 2009a). 1,1,2-Trichloroethane is a volatile organic compound that dissolves in water and breaks down slowly in the air and water. Direct contact of 1,1,2-trichloroethane with the skin results in burns. Animal studies have shown that inhalation of 1,1,2-trichloroethane affects the liver, kidneys, and nervous system. Based on animal studies, ingestion of

6 the chemical may cause stomach, blood, liver, kidney, and nervous system effects. The IARC has determined that 1,1,2-trichloroethane is not classifiable as a human carcinogen. The EPA limits the amount of 1,1,2-trichloroethane in drinking water to mg/l. OSHA has set a permissible exposure limit of 45 mg/m 3 for this substance in the workplace air, for a 8-hour day, 40-hour workweek (ATSDR 2009a). 1,1-Dichloroethane is a volatile organic compound that does not dissolve easily in water. Exposure to this chemical has resulted in arrhythmia in humans. Animal studies have shown that chronic exposure to high levels of 1,1-dichloroethane can cause kidney disease. Inhalation of high levels of the chemical by pregnant mothers caused delayed growth in their offspring. The DHHS, the IARC, and the EPA have not classified the substance for carcinogenicity. OSHA has set an occupational exposure limit of 400mg/m 3 of 1,1-dichloroethane in the workplace air for an 8-hour day, 40-hour workweek. The National Institute of Safety and Health (NIOSH) determines that a level of 12,150 mg/m 3 is can result in immediate damage to health or even death (ATSDR 2009a). 1,1-Dichloroethene is a volatile organic compound that breaks down very slowly in water but can be transferred to less harmful chemicals in soil. Inhalation of high levels of this chemical affects the central nervous system and can lead to breathlessness or fainting. Chronic inhalation of lower levels of 1,1-dichloroethene can lead to a loss in liver function. Animal studies have shown that breathing and/or ingesting high levels of this chemical can damage the liver, kidneys, lungs, and cause birth defects in offspring. Direct contact with the eyes or skin can cause irritation. The EPA classifies 1,1- dichloroethene as a possible human carcinogen. The EPA limits the amount of this chemical in drinking water to parts per million. The Occupational Safety and Health Administration (OSHA) has set an occupational exposure limit at 1 part per million in the workplace air for a 8-hour day, 40-hour workweek (ATSDR 2009a). 1,2-Dichloroethane is a volatile organic compound that breaks down very slowly in water. Ingestion or inhalation of large amounts of 1,2-dichloroethane has caused liver and kidney diseases as well as lung effects. Animal studies have shown that inhalation or ingestion of large amounts can cause damage to the immune system. Also, kidney disease has been seen after chronic ingestion of low doses of this substance. The DHHS, the IARC and the EPA have determined that 1,2-dichloroethane is a probable human carcinogen based on animal studies. The EPA limits the amount of this chemical in drinking water to mg/l. OSHA has set a limit of 50 parts per million for this chemical in the workplace air for 8-hour day, 40 hour workweek (ATSDR 2009a).

7 1,2-Dichloropropane is a volatile organic compound that is not rapidly broken down in the air or soil. Accidental inhalation or ingesting of this substance has led to difficulty breathing, coughing, headaches, nausea, vomiting, nosebleed, fatigue, and damage to blood cells, liver, and kidneys, anemia, coma, and death. Animal studies have shown that chronic inhalation of low levels of 1,2-dichloropropane causes damage to the liver kidney, and respiratory system. Inhalation of high levels causes death. Ingestion can cause reproductive effects. The IARC has not classified this substance as a possible human carcinogen. The EPA set a Maximum Contaminant Level (MCL) of for 1,2-dichloropropane in drinking water and recommends that no more than 0.52 parts per billion exists in the streams and lakes to prevent human health effects. OSHA has set a workplace air concentration limit of 75 parts per million for an 8-hour day, 40-hour workweek (ATSDR 2009a). 2-Butanone is a volatile organic compound that dissolves in water and breaks down slowly. It causes irritation of the nose, throat, skin, and eyes. Animal studies have shown that inhalation of high levels of 2-butanone can cause birth defects, loss of consciousness, and death. Ingestion caused nervous system effects including drooping eyelids and uncoordinated muscle movements. Acute inhalation and ingestion of low levels of 2-butanone cause temporary behavioral effects and mild kidney damage, respectively. The DHHS, the IARC, and the EPA have not classified 2-butanone as a human carcinogen. OSHA set an occupational exposure limit of 200 parts per million of 2-butanone in workplace air for an 8-hour day, 40-hour workweek (ATSDR 2009a). 2-Hexanone is a volatile organic compound that dissolves easily in water and can be broken down by microorganisms in water and soil. Inhalation of 2-hexanone can cause damage to the nervous system indicated by numbness, weakness, and tingling of the skin. Animal studies have shown that exposure to 2-hexanone has cause reproductive and birth defects. The DHHS, the IARC, and the EPA have not classified 2-hexanone as a human carcinogen. OSHA set an occupational exposure limit of 2-hexanone in workplace air to 100 parts per million for an 8-hour day, 40-hour workweek. The NIOSH recommends that workers be exposed to no more than an average of 1 part per million for a 10-hour day, 40-hour workweek (ATSDR 2009a). 2-Methylnaphthalene may have many of the same health effects as naphthalene and studies have shown that it causes lung injury (pulmonary alveolar proteinosis).also, it has been known to cause tumors in mice. There are no regulations for 2- methylnaphthalene (ATSDR 2009a). 3-Nitroaniline is a questionable carcinogen, and when heated to decomposition, the chemical releases toxic NO x fumes (Lewis 2008).

8 4-Methyl-2-pentanone, also known as MIBK, is a volatile organic compound that is highly flammable. It can cause irritation to the skin, eyes, and respiratory tract, headache, narcosis, coma, dermatitis, as well as liver and kidney damage. Animal studies have shown that exposure to MIBK can cause reduced fetal body weight, skeletal variations and increased fetal death. The NIOSH set an exposure limit of 500 parts per million of MIBK in workplace air (NIOSH 2009). The EPA has not classified MIBK as a human carcinogen and set the reference dose at 3 mg/m 3 (US EPA 2010). 4-Nitroaniline, also known as p-nitroaniline, is a semi-volatile organic compound. It is rapidly absorbed through the skin and can cause methemoglobinemia a decrease of the oxygen in the blood. Cyanosis (blue discoloration of the skin) can occur as the body loses oxygen. Also, headaches, weakness, irritability, drowsiness, shortness of breath, vomiting and unconsciousness may occur. It is possibly fatal if directly swallowed, inhaled, or absorbed through skin, and it has critical effects on the lungs, heart, blood and liver (CDC 2009). Acetone is a highly volatile organic compound that is flammable and dissolves in water. It is not a known carcinogen but breathing moderate to high levels can cause respiratory irritation and burning eyes, headaches, nausea, vomiting, unconsciousness, and possibly coma. The health effects of long term exposure to acetone include kidney, liver and nerve damage, and increased chance for birth defects. NIOSH recommends a limit of 250 parts per million in workplace air for up to a 10-hour day, over a 40-hour workweek (ATSDR 2009a). Benzoic acid is a colorless, oily liquid with a slight odor that can react with oxidizing materials. Benzoic acid is a combustible liquid and moderately toxic through ingestion and skin contact (Lewis 2008).It is not classified by the EPA as a human carcinogen, and the World Health Organization suggests a provisional tolerable intake to be 5 mg/kg/day (US EPA 2010). Carbon disulfide is a volatile organic compound that does not remain dissolved in water for long and moves through soil quickly. At very high exposure levels, carbon disulfide affects the nervous system and can be life-threatening. Inhalation of high levels of carbon disulfide can cause headaches, tiredness, and trouble sleeping. Direct contact with carbon disulfide can lead to skin burns. Animal studies have shown that carbon disulfide can affect brain, liver, and heart function. Also, when pregnant rats inhaled carbon disulfide some of the newborns died or had birth defects. The DHHS, the IARC, and the EPA have not classified carbon disulfide as a human carcinogen.

9 OSHA limits the amount of carbon in the workplace air to 20 parts per million for an 8- hour day, 40-hour workweek (ATSDR 2009a). cis-1,2-dichloroethene is a form of 1,2-dichloroethene, which is a volatile organic compound that breaks down very slowly in water. Ingestion or inhalation of large amounts of 1,2-dichloroethane have caused liver and kidney diseases as well as lung effects. Animal studies have shown that inhalation or ingestion of large amounts can cause damage to the immune system. Also, kidney disease has been seen after chronic ingestion of low doses of this substance. The DHHS, the IARC and the EPA have determined that 1,2-dichloroethane is a probable human carcinogen based on animal studies. The EPA limits the amount of this chemical in drinking water to mg/l. OSHA has set a limit of 50 parts per million for this chemical in the workplace air for an 8-hour day, 40 hour workweek (ATSDR 2009a). Dichlorodifluoromethane is a colorless gas that has an odor at very high concentrations. Exposure may occur through inhalation, skin and/or eye contact and may cause unconsciousness, liquid frostbite, asphyxia, dizziness, cardiac arrest, cardiac arrhythmia, and tremors. OSHA has set a limit of 1000 parts per million for this chemical in the workplace air for an 8-hour day, 40-hour workweek (CDC 2009). Total xylenes are volatile organic compounds that easily catch fire. They are naturally occurring in petroleum and coal tar.xylenes are sweet-smelling, colorless liquids. Xylenes are widely used in leather, printing and rubber industries as a solvent. They may cause developmental affects and negatively impact the liver, nervous system, and renal system. Exposure can also cause irritation of the eyes, nose, throat, and skin. Also dizziness, reduced muscle coordination and even death can occur. The limit for drinking water is 10 parts per million and for air in the workplace it is 100 parts per million for an 8-hour day, 40-hour workweek (ATSDR 2009a). trans-1,2-dichloroethene is a volatile organic compound. This chemical is manufactured and does not occur naturally. It is a clear liquid that both tastes and smells sweet. It is commonly used to produce vinyl chloride, as a solvent, and as an additive to gasoline to remove lead. There is a high likelihood that it is a carcinogen to humans and is known to affect the liver and renal system (ATSDR 2009a). Trichloroethene is a non-flammable volatile organic compound. It is colorless liquid that has a sweet odor and a sweet, burning taste. It is not believed to occur naturally in the environment. Exposure may cause developmental and nervous system effects. This chemical may also be a human carcinogen. Even breathing small amounts can cause headaches, irritation of the lung, hinder coordination, and cause difficulty

10 concentrating. If large amounts are inhaled, death can occur and nervous system and renal system may be damaged. Drinking small amounts can cause renal damage, hinder the immune system and impair development. Consuming larger amounts will cause nausea, unconsciousness, damage the heart and can cause death. Contact with the skin usually only causes a rash. The limit in drinking water is 5 parts per billion, and for air there is a 100 parts per million limit for an 8-hour day,40-hour workweek (ATSDR 2009a). Vinyl chloride is a volatile organic compound. It is a colorless gas with a sweet odor. It is not stable at high temperatures and easily burns. It is not naturally occurring but is manufactured often to make PVC for plastic products. Vinyl chloride is a human carcinogen and may cause developmental effects. It also affects the cardiovascular system, the immune system and the liver. Inhalation of vinyl chloride has varied effects depending on exposure time. Effects range from dizziness to unconsciousness and, in extreme circumstances, can even result in death. Levels in drinking water should not be in excess of milligrams per liter and levels in the air should not exceed 1 part per million (ATSDR 2009a). Metals found above detection limits in groundwater on the Bliss-Ellisville Site (MW-1) only: Arsenic persists in the environment and does not get destroyed, it only changes form. Arsenic readily dissolves in water. Breathing high levels of inorganic arsenic can lead to sore throat and irritated lungs, while ingesting high levels can lead to death. Exposure to low levels causes nausea, vomiting, a decrease in red and white blood cells, arrhythmia and damage to blood vessels. Chronic exposure to low levels of arsenic can cause darkening of the skin and warts. Ingestion of certain compounds can also cause diarrhea and kidney damage. The DHHS, the IARC, and the EPA have determined that inorganic arsenic is carcinogenic. Exposure to arsenic in the womb and early childhood may increase mortality in young adults. The EPA has set a limit of 0.01 ppm for arsenic in drinking water. OSHA has set a permissible exposure limit of 10 micrograms of arsenic per cubic meter of workplace air for an 8-hour day, 40-hour workweek (ATSDR 2009a). Mercury is a naturally occurring metal that builds up in the tissues of fish. All forms of mercury can affect the nervous system. Mercury in vapor form is the most dangerous because it can reach the brain. Exposure to high levels of metallic, inorganic, or organic

11 mercury can permanently damage the brain, kidneys, and developing fetus. Brain effects can include irritability, shyness, tremors, changes in vision or hearing, and memory problems. Acute exposure to high levels of metallic mercury vapors can lead to lung damage, nausea, vomiting, diarrhea, increases in blood pressure or heart rate, skin rashes, and eye irritation. The EPA has determined mercuric chloride and methyl mercury to be possible human carcinogens based on animal studies. Very young children are more sensitive to mercury than adults. Adverse effects that can be passed from the mother to the fetus include brain damage, mental retardation, incoordination, blindness, seizures and inability to speak. Children poisoned by mercury can develop problems with their nervous and digestive systems as well as kidney damage. The EPA limits the amount of mercury in drinking water to 2 parts per billion. The FDA has set a maximum permissible level of 1 part per million of methylmercury in seafood. OSHA has set a limit of 0.1 mg/m 3 of air for 8-hour day, 40-hour workweek (ATSDR 2009a). Selenium is a naturally occurring mineral element found in rocks and soils that may accumulate up the food chain. Chronic exposure to high levels of selenium can cause selenosis which results in hair loss, nail brittleness, neurological abnormalities, respiratory irritation, bronchial spasms and coughing. Acute exposures to high levels of selenium can cause nausea, vomiting, diarrhea, respiratory tract irritation, bronchitis, difficulty breathing, and stomach pains. Animal studies have shown that exposure leads to adverse reproductive effects. The IARC has not classified selenium as a human carcinogen. The EPA has determined that selenium sulfide only is a probable human carcinogen. The EPA restricts the amount of selenium allowed in public water supplies to 50 parts per billion. OSHA limits the amount of selenium in the air to 0.2 mg/m 3 for an 8-hour day, 40-hour workweek. ATSDR and the EPA determined that 5 micrograms of selenium per kg of body weight taken daily would not cause any adverse health effects over a lifetime (ATSDR 2009a). Silver is a naturally occurring element in the environment. Chronic exposure to high levels of silver can cause arygria, a blue-gray discoloration of the skin and other body tissues that is permanent but is not otherwise harmful to health. Inhalation of high levels of silver has resulted in breathing problems, lung and throat irritation, and stomach pains. Direct contact with silver can case mild allergic reactions such as rash, swelling, and inflammation in some people. The EPA has determined that silver is not classifiable as a human carcinogen. The EPA has limited the amount of silver in drinking water to 0.1 mg/l because of the arygria. OSHA limits silver in workplace air to 0.01 mg/m 3 for an 8-hour day, 40-hour workweek (ATSDR 2009a).