Dibromochloromethane

Derry Water Department

Dibromochloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Dibromochloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	0.200 ppb	3	1	ND - 0.600 ppb
2015	0.500 ppb	1	1	0.500 ppb
2016	0.847 ppb	19	18	ND - 2.80 ppb
2017	0.469 ppb	16	12	ND - 0.700 ppb
2018	0.600 ppb	16	12	ND - 0.900 ppb
2019	0.781 ppb	16	16	0.600 ppb - 1.000 ppb

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 dibromochloromethane was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

ppb = parts per billion

All test results

Date	Lab ID	Result
2016-02-17	1602-01178-002	0.600 ppb
2016-02-17	1602-01178-001	0.600 ppb
2016-02-17	1602-01178-004	0.500 ppb
2016-02-17	1602-01178-003	0.600 ppb
2016-05-09	1605-01082-001	0.800 ppb
2016-05-09	1605-01082-002	0.800 ppb
2016-05-09	1605-01082-003	0.800 ppb
2016-05-09	1605-01082-004	0.700 ppb
2016-08-02	1608-00332-002	1.60 ppb
2016-08-02	1608-00332-003	2.80 ppb
2016-08-02	1608-00332-004	0.900 ppb
2016-08-17	1608-02043-001	1.000 ppb
2016-08-17	1608-02043-002	0.900 ppb
2016-08-17	1608-02043-003	0.900 ppb
2016-08-17	1608-02043-004	1.000 ppb
2016-11-09	1611-00974-004	ND
2016-11-09	1611-00974-003	0.500 ppb
2016-11-09	1611-00974-002	0.600 ppb
2016-11-09	1611-00974-001	0.500 ppb
2017-02-15	1702-01108-001	ND
2017-02-15	1702-01108-002	ND
2017-02-15	1702-01108-003	ND
2017-02-15	1702-01108-004	ND
2017-05-16	1705-02220-001	0.600 ppb
2017-05-17	1705-02220-002	0.600 ppb
2017-05-17	1705-02220-003	0.600 ppb
2017-05-17	1705-02220-004	0.600 ppb
2017-08-07	1708-01128-001	0.600 ppb
2017-08-07	1708-01128-002	0.500 ppb
2017-08-07	1708-01128-003	0.600 ppb
2017-08-08	1708-01128-004	0.600 ppb
2017-11-15	1711-01620-004	0.700 ppb
2017-11-15	1711-01620-003	0.700 ppb
2017-11-15	1711-01620-001	0.700 ppb
2017-11-15	1711-01620-002	0.700 ppb
2018-02-14	1802-01100-001	ND
2018-02-14	1802-01100-002	ND
2018-02-14	1802-01100-003	ND
2018-02-14	1802-01100-004	ND
2018-05-14	1805-01955-002	0.800 ppb
2018-05-14	1805-01955-003	0.800 ppb
2018-05-14	1805-01955-004	0.800 ppb
2018-05-15	1805-01955-001	0.800 ppb
2018-08-15	1808-02227-001	0.800 ppb
2018-08-15	1808-02227-002	0.700 ppb
2018-08-15	1808-02227-003	0.800 ppb
2018-08-15	1808-02227-004	0.800 ppb
2018-11-14	1811-01462-004	0.800 ppb
2018-11-14	1811-01462-003	0.800 ppb
2018-11-14	1811-01462-001	0.800 ppb
2018-11-14	1811-01462-002	0.900 ppb
2019-02-12	1902-00993-001	0.700 ppb
2019-02-12	1902-00993-002	0.600 ppb
2019-02-12	1902-00993-003	0.800 ppb
2019-02-12	1902-00993-004	0.700 ppb
2019-05-13	1905-01580-004	0.900 ppb
2019-05-13	1905-01580-003	0.900 ppb
2019-05-13	1905-01580-002	1.000 ppb
2019-05-13	1905-01580-001	0.900 ppb
2019-08-13	1908-02035-001	0.700 ppb
2019-08-14	1908-02035-002	0.700 ppb
2019-08-14	1908-02035-003	0.700 ppb
2019-08-14	1908-02035-004	0.700 ppb
2019-11-12	1911-01344-002	0.800 ppb
2019-11-13	1911-01344-001	0.800 ppb
2019-11-13	1911-01344-003	0.800 ppb
2019-11-13	1911-01344-004	0.800 ppb