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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 29.9 ppb | 28 | 28 | 12.8 ppb - 59.3 ppb |
2015 | 27.3 ppb | 16 | 16 | 16.7 ppb - 39.9 ppb |
2016 | 28.9 ppb | 16 | 16 | 17.0 ppb - 43.3 ppb |
2017 | 29.6 ppb | 20 | 20 | 19.6 ppb - 47.5 ppb |
2018 | 32.4 ppb | 17 | 17 | 18.9 ppb - 49.9 ppb |
2019 | 33.6 ppb | 15 | 15 | 19.5 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 |
---|---|---|
2014-01-08 | 140109216 DBP 1S | 19.5 ppb |
2014-01-08 | 140109213 DBP 1S | 21.7 ppb |
2014-01-08 | 140109212 DBP 1S | 21.5 ppb |
2014-01-08 | 140109218 DBP 1S | 21.6 ppb |
2014-01-08 | 14109217 DBP 1ST | 20.9 ppb |
2014-01-08 | 140109214 DBP 1S | 15.5 ppb |
2014-01-08 | 140109215 DBP 1S | 12.9 ppb |
2014-01-08 | 140109211 DBP1ST | 12.8 ppb |
2014-04-11 | DBP 2ND Q 14 STA | 21.2 ppb |
2014-04-11 | 2ND Q 14STAGE2DB | 16.2 ppb |
2014-04-11 | STAGE 2 DBP 2NDQ | 16.9 ppb |
2014-04-11 | LRAA7 2ND Q 14 D | 16.5 ppb |
2014-04-11 | DBP 2ND Q 14 STA | 17.4 ppb |
2014-04-11 | STAGE 2DBP 2ND Q | 27.0 ppb |
2014-04-11 | LRAA8 2ND Q 14 D | 20.8 ppb |
2014-04-11 | DBP2ND Q 14 STAG | 22.3 ppb |
2014-07-09 | S4G11068 3RD Q 1 | 51.0 ppb |
2014-07-09 | S4G11062 3RD Q 1 | 59.3 ppb |
2014-07-09 | S4G11064 3RD Q 1 | 50.3 ppb |
2014-07-09 | S4G11066 3RD Q 1 | 52.0 ppb |
2014-07-09 | S4G11067 3RD Q 1 | 48.9 ppb |
2014-07-09 | S4G11065 3RD Q 1 | 43.2 ppb |
2014-07-09 | S4G1106 3RD Q 14 | 39.9 ppb |
2014-07-09 | S4G11063 3RD Q 1 | 52.8 ppb |
2014-10-08 | 4 Q 14 DBP SIT E | 31.4 ppb |
2014-10-08 | 4 Q 14 DBP SITE | 36.1 ppb |
2014-10-08 | 4 Q 2014 DBP SIT | 32.2 ppb |
2014-10-08 | 4 Q 14 DBP SITE | 35.5 ppb |
2015-01-07 | 107152 1ST Q 15 | 17.5 ppb |
2015-01-07 | 010715 1 DBP 1ST | 18.5 ppb |
2015-01-07 | 0107154 1ST Q 15 | 17.8 ppb |
2015-01-07 | 0107152 1ST Q 15 | 18.6 ppb |
2015-04-08 | 4/8/15-2 | 19.3 ppb |
2015-04-08 | 4/8/15-3 | 16.7 ppb |
2015-04-08 | 4/8/15-1 | 23.4 ppb |
2015-04-08 | 4/8/15-4 | 18.6 ppb |
2015-07-08 | 070815 -1 | 32.8 ppb |
2015-07-08 | 07/08/15 -2 | 39.4 ppb |
2015-07-08 | 07/08/15 -4 | 35.4 ppb |
2015-07-08 | 07/08/15 -3 | 39.9 ppb |
2015-10-09 | 2 4TH Q 15 DBPS | 35.5 ppb |
2015-10-09 | 4TH Q 2015 DBPS | 31.0 ppb |
2015-10-09 | 3 4TH Q 2015 DBP | 38.3 ppb |
2015-10-09 | 4 15 4TH Q DBPS | 34.7 ppb |
2016-01-05 | 0105162 DBP | 17.4 ppb |
2016-01-05 | 0105163 DBP | 19.0 ppb |
2016-01-05 | 0105164 DBP | 20.2 ppb |
2016-01-05 | 15161 DBP 16 | 17.0 ppb |
2016-04-05 | 04/05/2016-84 | 22.3 ppb |
2016-04-05 | 04/05/2016-2974 | 22.4 ppb |
2016-04-05 | 04/05/2016-4264 | 22.0 ppb |
2016-04-05 | 04/05/2016-2660 | 23.8 ppb |
2016-07-05 | 07/05/2016-2660 | 38.9 ppb |
2016-07-05 | 07/05/2016-2974 | 35.0 ppb |
2016-07-05 | 07/05/2016-84 | 36.0 ppb |
2016-07-05 | 07/05/2016-4264 | 25.9 ppb |
2016-10-04 | 10/04/2016-03 | 35.8 ppb |
2016-10-04 | 10/04/2016-01 | 43.3 ppb |
2016-10-04 | 10/04/2016-02 | 40.0 ppb |
2016-10-04 | 10/04/2016-04 | 42.7 ppb |
2017-01-03 | 01/03/2017-01 | 19.7 ppb |
2017-01-03 | 01/03/2017-02 | 20.2 ppb |
2017-01-03 | 01/03/2017-03 | 19.6 ppb |
2017-01-03 | 01/03/2017-04 | 20.7 ppb |
2017-04-04 | 0420170821 | 22.2 ppb |
2017-04-04 | 042017943 | 22.9 ppb |
2017-04-04 | 0420140943 | 22.8 ppb |
2017-04-04 | 0417821 | 22.2 ppb |
2017-04-04 | 0420170918 | 27.7 ppb |
2017-04-04 | 042017101 | 22.0 ppb |
2017-04-04 | 0420171001 | 22.0 ppb |
2017-04-04 | 042017918 | 27.7 ppb |
2017-07-05 | 7520171115 | 34.6 ppb |
2017-07-05 | 7520171114 | 35.6 ppb |
2017-07-05 | 7520171112 | 38.8 ppb |
2017-07-05 | 7520171113 | 39.2 ppb |
2017-10-03 | TOTOCT 2017 DBP | 40.7 ppb |
2017-10-03 | TOT OCT2017 1 | 39.9 ppb |
2017-10-03 | TOT OCT 2017 DBP | 45.4 ppb |
2017-10-03 | TOT OCT 2017 DBP | 47.5 ppb |
2018-01-09 | 10918 4264 DELAW | 20.8 ppb |
2018-01-09 | 10918 2974 COLVI | 18.9 ppb |
2018-01-09 | 10918 DBP9 2660 | 20.3 ppb |
2018-01-09 | 0109181 1ST Q DB | 20.8 ppb |
2018-01-09 | 10918 84 HAWTHOR | 26.7 ppb |
2018-04-03 | 4318 84 HAWTHORN | 27.3 ppb |
2018-04-03 | 4318 2974 COLVIN | 21.3 ppb |
2018-04-03 | 4318 2660 NFB DB | 22.5 ppb |
2018-04-03 | 4318 4264 DELAWA | 23.1 ppb |
2018-07-03 | 3RD Q 2018 DBP 8 | 49.9 ppb |
2018-07-03 | DBP 3RD Q 18 266 | 40.9 ppb |
2018-07-03 | DBP 3RD Q 18 297 | 44.0 ppb |
2018-07-03 | DBP 3RD Q 18 426 | 40.3 ppb |
2018-10-09 | TONA 4 DBP 4TH Q | 48.3 ppb |
2018-10-09 | TONA 3 DBP 4TH Q | 40.4 ppb |
2018-10-09 | TONA 2 DBP 4TH Q | 42.0 ppb |
2018-10-09 | TONA 1 DBP 4TH Q | 43.5 ppb |
2019-01-07 | 2660 NIAFALLBLVD | 22.3 ppb |
2019-01-07 | 4264 DEL | 22.4 ppb |
2019-01-07 | 84 HAW | 23.1 ppb |
2019-01-10 | 2974 COL | 19.5 ppb |
2019-04-09 | 4264 DELAWARE | 25.6 ppb |
2019-04-09 | 84 HAWTHORNE | 27.7 ppb |
2019-04-09 | 2660 NFBLVD | 24.6 ppb |
2019-04-09 | 2974 COLVIN | 21.8 ppb |
2019-07-09 | 2974 COLVIN 3RD | 45.3 ppb |
2019-07-09 | 4264 DELAWARE 3Q | 45.2 ppb |
2019-07-09 | 2660 NIA FALL 3Q | 47.9 ppb |
2019-10-08 | 4264 DEL 4QTR | 38.1 ppb |
2019-10-08 | 2660 NIA FALLS 4 | 50.2 ppb |
2019-10-08 | 2974 COLVIN 4QTR | 43.0 ppb |
2019-10-08 | 84 HAW 4QTR | 47.0 ppb |