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Simazine in Texas

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Simazine is a widely used herbicide that has been associated with endocrine disruption and cancer in experimental studies. [read more]

Simazine Simazine is a widely used herbicide similar to atrazine. Exposure to simazine has been associated with neuroendocrine toxicity and the development of mammary and pituitary gland tumors (U.S. Environmental Protection Agency (USEPA) 2006b). Simazine is very likely to leach into groundwater and run off into surface water (California Environmental Protection Agency 2001a). According to a 1994 EPA study, simazine was the eighth most widely detected pesticide in 19 of 30 states and the most frequently detected pesticide in California's Well Inventory Database (USEPA 1994a). At the time of the study, seven percent of samples had simazine levels that exceeded the maximum contaminant level (MCL) of 0.004 mg/L (4 parts per billion or ppb), which is a legal limit for the highest level of a contaminant that is allowed in drinking water (California Environmental Protection Agency 2001a). Simazine causes mammary gland (breast) cancer and ovarian tumors in rats. Some studies have reported simazine to act as a weak mutagen, which means it has the potential to damage DNA (Taets 1998). Simazine also causes damage to the ovary and changes in blood measures, including decreased red blood cell number and increased platelets, which are important in blood clotting. Other organs damaged by simazine in laboratory animals after long-term exposure include: brain, liver, kidney, adrenal gland, heart, lung and thyroid. In rats, developmental exposure to simazine causes delayed bone formation (Integrated Risk Information System (IRIS) 1994a). Sheep, which are more susceptible to simazine than rats, show damage to the testes and abnormal sperm development following simazine exposure (California Environmental Protection Agency 2001a). Many scientists believe that simazine causes mammary gland tumors (and ovarian toxicity) by disrupting reproductive hormones (Stevens 1994). Following long-term exposure, simazine has been shown to increase blood levels of estrogen and growth hormone, and decrease levels of prolactin and progesterone (California Environmental Protection Agency 2001a).

The Most Polluted Communities in Texas

29 water utilities reported detecting Simazine in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Simazine level

Rank	System	Population Served	Positive test results of total reported tests	Average Level (Range)
1	Tra Tarrant County Water Project Arlington, TX	25	4 of 4	0.26 ppb (0.2 to 0.33 ppb)
2	Dallas County Park Cities Mud Dallas, TX	25	3 of 4	0.25 ppb (0 to 0.5 ppb)
3	Waterwood Mud 1 Huntsville, TX	900	3 of 4	0.24 ppb (0 to 0.61 ppb)
4	Travis County Wcid 18 Houston, TX	4,826	1 of 6	0.22 ppb (0 to 1.3 ppb)
5	City of Midlothian Midlothian, TX	8,000	8 of 9	0.2 ppb (0 to 0.31 ppb)
6	Tra Huntsville Regional Water Supply Huntsville, TX	25	3 of 4	0.19 ppb (0 to 0.45 ppb)
7	Dallas Water Utilities Sunnyvale, TX	1,188,580	7 of 8	0.19 ppb (0 to 0.5 ppb)
8	City of Grapevine Grapevine, TX	42,059	3 of 4	0.17 ppb (0 to 0.3 ppb)
9	City of Lewisville Lewisville, TX	80,768	3 of 4	0.15 ppb (0 to 0.24 ppb)
10	Gulf Coast Water Authority TX City Texas City, TX	25	3 of 4	0.14 ppb (0 to 0.23 ppb)

Health Based Limits for Simazine

Standard	Description	Level
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.	4 ppb
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.	4 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.	4 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.	700 ppb

Violation Summary for Simazine in Texas

There are no violations reported for this contaminant in Texas