A review of nitrates in drinking water: maternal exposure and adverse reproductive and developmental outcomes

Abstract

In this review, we present an update on maternal exposure to nitrates in drinking water in relation to possible adverse reproductive and developmental effects, and discuss nitrates in drinking water in the United States. The current standard for nitrates in drinking water is based on retrospective studies and approximates a level that protects infants from methemoglobinemia, but no safety factor is built into the standard. The current standard applies only to public water systems. Animal studies have found adverse reproductive effects resulting from higher doses of nitrate or nitrite. The epidemiologic evidence of a direct exposure-response relationship between drinking water nitrate level and adverse reproductive effect is still not clear. However, some reports have suggested an association between exposure to nitrates in drinking water and spontaneous abortions, intrauterine growth restriction, and various birth defects. Uncertainties in epidemiologic studies include the lack of individual exposure assessment that would rule out confounding of the exposure with some other cause. We conclude that the current literature does not provide sufficient evidence of a causal relationship between exposure to nitrates in drinking water and adverse reproductive effects.

The detoxication of nitrate by two antioxidants or a probiotic, and the effects on blood and seminal plasma profiles and reproductive function of New Zealand White rabbit bucks

“…Nitrate is a serious problem worldwide, and recent research indicated that nitrate in ground and well water is increasing (Manassaram et al, 2006;Burow et al, 2010;Cockburn et al, 2010;Ward et al, 2010). The use of high levels of nitrate on rabbit performance was investigated by Gilman et al (1998); Bassuny et al (2004); Shehata (2005); and Djekoun-Bensoltane et al (2007).…”

An evaluation of semi-quantitative test strips for the measurement of nitrate in drinking water in epidemiologic studies

“…Exposure to nitrate or nitrite in drinking water is associated with methemoglobinemia in infants, and possibly cancer (Grosse et al, 2006) and selected reproductive and developmental outcomes (Manassaram et al, 2006). Levels in water can be measured accurately with laboratory assays, but in the context of a large epidemiologic study, this may be costprohibitive, and poses logistical challenges due to obtaining and transporting water samples.…”

A patient with rheumatic heart disease presented with central cyanosis due to acquired methemoglobinemia during late pregnancy – A rare association

“…There are some literatures which have demonstrated that methemoglobinemia can be associated with drinking of tube-well water. 6 As she is not having methemoglobin in normal range even after delivery, so it is also supporting that due to drinking contaminated water, her baseline value is on higher side. Though heterozygote's variety of methemoglobinemia can present as same pattern and for this genetic study is needed.…”

“…7 Our patient had excessive fatigability with mild tachypnea and tachycardia. As there are evidences which suggest that epidural anesthesia may further cause neonatal methemoglobinemia 6 and she was deeply cyanosed and fatigued so obstetricians have decided to go for elective caesarean section at 37th completed gestational weeks. In our case, the baby was affected due to the effect of general anesthesia but not due to methemoglobinemia.…”