The acute toxicity of<unk>  is low. "Substantial disagreement" exists about the long-term risks of<unk>  exposure. The two areas of possible concern are that (i)<unk>  could be a precursor to<unk>  in the lower gut, and<unk>  is a precursor to nitrosamines, which are implicated in carcinogenesis, and (ii)<unk>  is implicated in methemoglobinemia, a disorder of hemoglobin in red blood cells. Methemoglobinemia<unk> s do not affect infants and pregnant women. Blue baby syndrome is caused by a number of other factors such as gastric upset, such as diarrheal infection, protein intolerance, heavy metal toxicity etc., with<unk> s playing a minor role. Drinking water standards Through the Safe Drinking Water Act, the United States Environmental Protection Agency has set a maximum contaminant level of 10 mg/L or 10 ppm of<unk>  in drinking water. An acceptable daily intake (ADI) for<unk>  ions was established in the range of 0–3.7 mg (kg body weight)−1 day−1 by the Joint FAO/WHO Expert Committee on Food Additives (JEFCA). Aquatic toxicity Sea surface<unk>  from the World Ocean Atlas In freshwater or estuarine systems close to land,<unk>  can reach concentrations that are lethal to fish. While<unk>  is much less toxic than ammonia, levels over 30 ppm of<unk>  can inhibit growth, impair the immune system and cause stress in some aquatic species.<unk>  toxicity remains a subject of debate. In most cases of excess<unk>  concentrations in aquatic systems, the primary sources are wastewater discharges, as well as surface runoff from agricultural or landscaped areas that have received excess<unk>  fertilizer. The resulting eutrophication and algae blooms result in anoxia and dead zones. As a consequence, as<unk>  forms a component of total dissolved solids, they are widely used as an indicator of water quality.
Nitrate
Bromide
Haloalkane
Phosphine
Saline 
Alcohols 
Phosphate
Gluten