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EWG's Tap Water Database — 2021 UPDATE

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Atrazine

City of Merced

Atrazine is a herbicide commonly detected in drinking water that comes from cornfield and other agricultural runoff. It is a hormone disrupter that harms the male and female reproductive systems of people and wildlife. Read More.

Federal laws allow up to 3 parts per billion of atrazine in treated tap water. Water suppliers average atrazine measurements collected over a year, which means that the reported values underestimate intense spikes of elevated exposures during the periods in late spring and early summer when atrazine is applied in large amounts on farm fields.

Human epidemiological studies suggest that federal standards for atrazine are insufficient to protect public health. In 1999 the California Office of Environmental Health Hazard Assessment set a public health goal of 0.15 parts per billion for atrazine in drinking water, based on a study finding increased rates of breast cancer in rats exposed to the chemical. California’s legal maximum for atrazine in tap water is 1 ppb.

Click here to read more about atrazine.

MORE ABOUT THIS CONTAMINANT

 

63

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND30ND
2015ND120ND
2016ND260ND
2017ND10ND
2018N/A00N/A
2019ND210ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.1 ppb

The EWG Health Guideline of 0.1 ppb for atrazine was defined by EWG based on epidemiological studies of human exposure to atrazine in drinking water.. This health guideline protects against harm to the developing fetus, harm to the reproductive system and hormone disruption.

EPA Maximum Contaminant
Level (MCL) 3 ppb

The legal limit for atrazine, established in 1991, was based on a toxicity study in laboratory animals conducted in the 1980s. This limit does not fully protect against harm to the reproductive system, harm to the developing fetus, and hormone disruption.

ppb = parts per billion

All test results

Date Lab ID Result
2014-01-095810-041-0955ND
2014-01-095810-019-1109ND
2014-01-095810-011-1445ND
2015-01-295810-004-1409ND
2015-01-295810-054-1008ND
2015-01-295810-015-0828ND
2015-01-295810-016-0855ND
2015-01-295810-043-0843ND
2015-01-295810-005-1359ND
2015-01-295810-020-1341ND
2015-01-295810-003-0930ND
2015-01-295810-002-0923ND
2015-01-295810-001-0915ND
2015-04-305810-008-0940ND
2015-08-065810-021-1115ND
2016-02-125810-023-0931ND
2016-02-125810-022-1030ND
2016-02-195810-049-0935ND
2016-02-195810-054-0951ND
2016-02-195810-048-0858ND
2016-02-195810-042-0919ND
2016-05-109590-057-1600ND
2016-09-019590-011-0901ND
2016-09-019590-022-1335ND
2016-09-019590-002-1400ND
2016-09-019590-041-1020ND
2016-09-019590-021-1450ND
2016-09-019590-003-1255ND
2016-09-019590-020-1120ND
2016-09-019590-005-1340ND
2016-09-019590-019-1055ND
2016-09-019590-043-1235ND
2016-09-019590-016-1030ND
2016-09-019590-054-0846ND
2016-09-019590-015-0810ND
2016-09-019590-048-0910ND
2016-09-019590-049-0945ND
2016-09-299590-001-0910ND
2016-10-139590-023-0934ND
2016-10-139590-004-0923ND
2016-12-019590-042-0854ND
2017-03-099590-008-0840ND
2019-08-065810-054-1100ND
2019-08-065810-049-1030ND
2019-08-065810-048-0755ND
2019-08-065810-043-1000ND
2019-08-065810-016-0820ND
2019-08-065810-042-0845ND
2019-08-085810-019-0820ND
2019-08-085810-020-0915ND
2019-08-085810-041-0855ND
2019-08-085810-021-0725ND
2019-08-135810-015-0955ND
2019-08-135810-022-0725ND
2019-08-135810-003-0747ND
2019-08-135810-004-0830ND
2019-08-135810-023-0855ND
2019-08-135810-005-0850ND
2019-09-195810-001-1230ND
2019-10-035810-011-1220ND
2019-10-175810-011-0930ND
2019-11-265810-008-0825ND
2019-12-105810-008-0841ND