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EWG's Tap Water Database — 2021 UPDATE

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Total trihalomethanes (TTHMs)

Town of Tonawanda Water Department

Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform. Read More.

Studies conducted in the U.S. and Europe have found that drinking tap water that carries disinfection byproducts increases the risk of developing bladder cancer. In animal studies, all trihalomethanes cause liver, kidney and intestinal tumors. Some human epidemiological studies also reported an association between disinfection byproducts and an increased risk of problems during pregnancy, including spontaneous miscarriage, cardiovascular defects, neural tube defects and low birth weight.

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

 

112

Samples

0

Samples exceeding legal limit (MCL)

112

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201429.9 ppb282812.8 ppb - 59.3 ppb
201527.3 ppb161616.7 ppb - 39.9 ppb
201628.9 ppb161617.0 ppb - 43.3 ppb
201729.6 ppb202019.6 ppb - 47.5 ppb
201832.4 ppb171718.9 ppb - 49.9 ppb
201933.6 ppb151519.5 ppb - 50.2 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.15 ppb

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

EPA Maximum Contaminant
Level (MCL) 80 ppb

The legal limit for the group of four trihalomethanes, established in 1998, was based on the need for residual disinfectant levels in water served to customers and the cost of treatment. This limit does not fully protect against the risk of cancer due to exposure to trihalomethanes.

ppb = parts per billion

All test results

Date Lab ID Result
2014-01-08140109216 DBP 1S19.5 ppb
2014-01-08140109213 DBP 1S21.7 ppb
2014-01-08140109212 DBP 1S21.5 ppb
2014-01-08140109218 DBP 1S21.6 ppb
2014-01-0814109217 DBP 1ST20.9 ppb
2014-01-08140109214 DBP 1S15.5 ppb
2014-01-08140109215 DBP 1S12.9 ppb
2014-01-08140109211 DBP1ST12.8 ppb
2014-04-11DBP 2ND Q 14 STA21.2 ppb
2014-04-112ND Q 14STAGE2DB16.2 ppb
2014-04-11STAGE 2 DBP 2NDQ16.9 ppb
2014-04-11LRAA7 2ND Q 14 D16.5 ppb
2014-04-11DBP 2ND Q 14 STA17.4 ppb
2014-04-11STAGE 2DBP 2ND Q27.0 ppb
2014-04-11LRAA8 2ND Q 14 D20.8 ppb
2014-04-11DBP2ND Q 14 STAG22.3 ppb
2014-07-09S4G11068 3RD Q 151.0 ppb
2014-07-09S4G11062 3RD Q 159.3 ppb
2014-07-09S4G11064 3RD Q 150.3 ppb
2014-07-09S4G11066 3RD Q 152.0 ppb
2014-07-09S4G11067 3RD Q 148.9 ppb
2014-07-09S4G11065 3RD Q 143.2 ppb
2014-07-09S4G1106 3RD Q 1439.9 ppb
2014-07-09S4G11063 3RD Q 152.8 ppb
2014-10-084 Q 14 DBP SIT E31.4 ppb
2014-10-084 Q 14 DBP SITE36.1 ppb
2014-10-084 Q 2014 DBP SIT32.2 ppb
2014-10-084 Q 14 DBP SITE35.5 ppb
2015-01-07107152 1ST Q 1517.5 ppb
2015-01-07010715 1 DBP 1ST18.5 ppb
2015-01-070107154 1ST Q 1517.8 ppb
2015-01-070107152 1ST Q 1518.6 ppb
2015-04-084/8/15-219.3 ppb
2015-04-084/8/15-316.7 ppb
2015-04-084/8/15-123.4 ppb
2015-04-084/8/15-418.6 ppb
2015-07-08070815 -132.8 ppb
2015-07-0807/08/15 -239.4 ppb
2015-07-0807/08/15 -435.4 ppb
2015-07-0807/08/15 -339.9 ppb
2015-10-092 4TH Q 15 DBPS35.5 ppb
2015-10-094TH Q 2015 DBPS31.0 ppb
2015-10-093 4TH Q 2015 DBP38.3 ppb
2015-10-094 15 4TH Q DBPS34.7 ppb
2016-01-050105162 DBP17.4 ppb
2016-01-050105163 DBP19.0 ppb
2016-01-050105164 DBP20.2 ppb
2016-01-0515161 DBP 1617.0 ppb
2016-04-0504/05/2016-8422.3 ppb
2016-04-0504/05/2016-297422.4 ppb
2016-04-0504/05/2016-426422.0 ppb
2016-04-0504/05/2016-266023.8 ppb
2016-07-0507/05/2016-266038.9 ppb
2016-07-0507/05/2016-297435.0 ppb
2016-07-0507/05/2016-8436.0 ppb
2016-07-0507/05/2016-426425.9 ppb
2016-10-0410/04/2016-0335.8 ppb
2016-10-0410/04/2016-0143.3 ppb
2016-10-0410/04/2016-0240.0 ppb
2016-10-0410/04/2016-0442.7 ppb
2017-01-0301/03/2017-0119.7 ppb
2017-01-0301/03/2017-0220.2 ppb
2017-01-0301/03/2017-0319.6 ppb
2017-01-0301/03/2017-0420.7 ppb
2017-04-04042017082122.2 ppb
2017-04-0404201794322.9 ppb
2017-04-04042014094322.8 ppb
2017-04-04041782122.2 ppb
2017-04-04042017091827.7 ppb
2017-04-0404201710122.0 ppb
2017-04-04042017100122.0 ppb
2017-04-0404201791827.7 ppb
2017-07-05752017111534.6 ppb
2017-07-05752017111435.6 ppb
2017-07-05752017111238.8 ppb
2017-07-05752017111339.2 ppb
2017-10-03TOTOCT 2017 DBP40.7 ppb
2017-10-03TOT OCT2017 139.9 ppb
2017-10-03TOT OCT 2017 DBP45.4 ppb
2017-10-03TOT OCT 2017 DBP47.5 ppb
2018-01-0910918 4264 DELAW20.8 ppb
2018-01-0910918 2974 COLVI18.9 ppb
2018-01-0910918 DBP9 266020.3 ppb
2018-01-090109181 1ST Q DB20.8 ppb
2018-01-0910918 84 HAWTHOR26.7 ppb
2018-04-034318 84 HAWTHORN27.3 ppb
2018-04-034318 2974 COLVIN21.3 ppb
2018-04-034318 2660 NFB DB22.5 ppb
2018-04-034318 4264 DELAWA23.1 ppb
2018-07-033RD Q 2018 DBP 849.9 ppb
2018-07-03DBP 3RD Q 18 26640.9 ppb
2018-07-03DBP 3RD Q 18 29744.0 ppb
2018-07-03DBP 3RD Q 18 42640.3 ppb
2018-10-09TONA 4 DBP 4TH Q48.3 ppb
2018-10-09TONA 3 DBP 4TH Q40.4 ppb
2018-10-09TONA 2 DBP 4TH Q42.0 ppb
2018-10-09TONA 1 DBP 4TH Q43.5 ppb
2019-01-072660 NIAFALLBLVD22.3 ppb
2019-01-074264 DEL22.4 ppb
2019-01-0784 HAW23.1 ppb
2019-01-102974 COL19.5 ppb
2019-04-094264 DELAWARE25.6 ppb
2019-04-0984 HAWTHORNE27.7 ppb
2019-04-092660 NFBLVD24.6 ppb
2019-04-092974 COLVIN21.8 ppb
2019-07-092974 COLVIN 3RD45.3 ppb
2019-07-094264 DELAWARE 3Q45.2 ppb
2019-07-092660 NIA FALL 3Q47.9 ppb
2019-10-084264 DEL 4QTR38.1 ppb
2019-10-082660 NIA FALLS 450.2 ppb
2019-10-082974 COLVIN 4QTR43.0 ppb
2019-10-0884 HAW 4QTR47.0 ppb