Nitrite

Portsmouth Water Works

Nitrite, closely related to the fertilizer chemical nitrate, comes from urban runoff and from fertilizer applied to agricultural lands to pollute drinking water. Nitrite is significantly more toxic than nitrate. Excessive nitrite in water can cause oxygen deprivation in infants and increase the risk of cancer.

MORE ABOUT THIS CONTAMINANT

Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Range of results
2014	ND	10	ND
2015	ND	9	ND
2016	ND	9	ND
2017	N/A	0	N/A
2018	ND	1	ND
2019	ND	6	ND

ppm = parts per million

State and national drinking water standards and health guidelines

EPA Maximum Contaminant
Level (MCL) 1 ppm

The legal limit for nitrite, established in 1991, was based on the rate of conversion of ingested nitrate into nitrite in adults. This limit may not fully protect against the risk of cancer due to nitrite exposure.

ppm = parts per million

All test results

Date	Lab ID	Result
2014-01-27	A400382001	ND
2014-01-27	A400382002	ND
2014-01-27	A400382003	ND
2014-02-03	A400530002	ND
2014-02-03	A400530003	ND
2014-02-03	A400530001	ND
2014-04-02	A401472001	ND
2014-07-01	A404344001	ND
2014-07-17	A405023001	ND
2014-11-04	A408919001	ND
2015-01-20	A500311005	ND
2015-01-20	A500311006	ND
2015-01-20	A500311004	ND
2015-01-20	A500311001	ND
2015-01-20	A500311002	ND
2015-04-01	A501436001	ND
2015-07-01	A504576001	ND
2015-07-08	A504792001	ND
2015-10-22	A508968001	ND
2016-02-03	B600549001	ND
2016-02-03	B600549003	ND
2016-02-03	B600549005	ND
2016-02-08	B600586005	ND
2016-02-08	B600586003	ND
2016-02-08	B600586001	ND
2016-04-14	B601897001	ND
2016-08-18	B607708003	ND
2016-09-20	37868-001	ND
2018-02-08	43406-004	ND
2019-01-29	1901-02581-001	ND
2019-01-29	1901-02583-001	ND
2019-01-29	1901-02584-001	ND
2019-01-29	1901-02595-001	ND
2019-01-29	1901-02600-001	ND
2019-08-15	1908-02437-001	ND