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National Drinking Water Database
Hexachlorobenzene (HCB) in Maryland
Hexachlorobenzene is a pollutant from metal refineries and agricultural chemical factories. [read more]
Hexachlorobenzene (HCB) is one of 12 persistent organic pollutants (POP), called the "dirty dozen," that are scheduled for global phase-out under the international POP treaty (Stockholm Convention on persistent organic pollutants (POPs) 2009).
Hexachlorobenzene was widely used as a pesticide until 1965. Although hexachlorobenzene is not produced as an end product in the U.S., it is a byproduct or impurity in other chlorinated compounds, including trichloroethylene, vinyl chloride, carbon tetrachloride and several pesticides (Agency for Toxic Substances and Disease Registry (ATSDR) 2002c).
Annually, tens of thousands of pounds of hexachlorobenzene are released into the environment, primarily onto the land. The largest emissions are reported for the solvent recovery industry and by chemical plants (U.S. Environmental Protection Agency (USEPA) 2009i).
As a class, organochlorine chemicals like HCB are toxic, persistent, bioaccumulative, and lipophilic ("fat-loving"). This means that they build up and are stored in fatty tissues and fluids, such as breast milk, and can be passed on to fetuses and infants during pregnancy and lactation. Organochlorine pesticides cause significant neurotoxicity in laboratory animals and humans, which is not surprising since they were designed to attack the nervous system of insects. In addition, many of these pesticides disrupt the hormone system.
In a mass HCD poisoning in Turkey (1955-1959), people developed skin lesions, liver and thyroid damage, osteoporosis and arthritis. Higher death rates were observed among newborn babies born to exposed women (ATSDR 2002c).
Short-term exposures at levels above the maximum contaminant level (MCL) may cause skin lesions, and nerve and liver damage. Longer-term exposure to levels that exceed the MCL can cause damage to liver, thyroid, adrenal gland, bile duct, kidney, thymus, spleen, lymph node and may cause cancer. Other effects include hypothyroidism, ovarian toxicity, immunotoxicity and alterations in calcium regulation and bone structure. Developmental exposure causes neurotoxicity and decreased immune function (International Programme on Chemical Safety (IPCS) 1997). Hexachlorobenzene is "reasonably anticipated" to be a human carcinogen on the basis of laboratory animal studies (liver and thyroid tumors) and has been associated with thyroid cancer, soft tissue sarcoma and brain cancer in men living near a factory in Flix, Spain that produced large amounts of HCB (and other organochlorines) for decades (National Toxicology Program (NTP) 2002a).
The Most Polluted Communities in Maryland
2 water utilities reported detecting Hexachlorobenzene (HCB) in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies
Ranked by highest average Hexachlorobenzene (HCB) level
|Rank||System||Population Served||Positive test results of total reported tests||Average Level|
|1||Luke / Newpage Luke Mill|
|184||1 of 8||0.03 ppb|
(0 to 0.2 ppb)
|25,000||1 of 11||< 0.01 ppb|
(0 to 0.02 ppb)
Health Based Limits for Hexachlorobenzene (HCB)
|Maximum Contaminant Limit Goal (MCLG)||A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.||0 ppb|
|EPA Human Health Water Quality Criteria||Water quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.||<0.01 ppb|
|One in one million (10-6) Cancer Risk||The concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.||0.02 ppb|
|California Public Health Goals||Defined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.||0.03 ppb|
|Maximum Contaminant Limit (MCL)||The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.||1 ppb|
|One in ten thousand (10-4) Cancer Risk||The concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.||2 ppb|
|Drinking Water Equivalent Level||A lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.||30 ppb|
|Children's health-based limit for 1-day exposure||Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for up to one day of exposure. The One-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.||50 ppb|
|Children's health-based limit for 10-day exposure||Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic effects for up to ten days of exposure. The Ten-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.||50 ppb|
Violation Summary for Hexachlorobenzene (HCB) in Maryland
There are no violations reported for this contaminant in Maryland