Groundwater nitrates

In view of experience with the groundwater nitrate problem and the possibility of a large unsaturated time-lag in British aquifer systems (especially in the Chalk), it is necessary to address the following questions in the above investigation ... 

Nitrate, which is produced by oxidation of nitrogen, is a monovalent polyanion having the formula N03. Most metal nitrates are soluble in water and occur in trace amounts in surface- and groundwaters. Nitrate is toxic to human health and, chronic exposure to high concentrations of nitrate, may cause methemoglobinemia. Maximum contaminant limit in potable water imposed by U.S. EPA is 10 mg nitrate as nitrogen/L. 

Staver, K. W., and Brinsfield, R. B. (1998). Use of cereal grain winter cover crops to reduce groundwater nitrate contamination in the Mid-Adantic coastal plain. J. Soil Water Conserv. 53, 230-240. 

Kreitler C. W. (1979) Nitrogen-isotope ratio studies of soils and groundwater nitrate from alluvial fan aquifers in Texas. J. Hydrol. 42, 147-170. 

Yuan L.J. Pang Z.H. 2010. Research on isotopes in groundwater nitrate pollution A review. Hydrogeology Engineering Geology 37(2) 108-113 (in Chinese). 

Zhou X. Jiang YH. 2007. Application of nitrogen and oxygen isotopes to the study of groundwater nitrate contamination. Acta Geoscientica Sinica 2%(4) 389-395 (in Chinese). 

Zhang, M., et al. 1998. Assessing groundwater nitrate contamination for resource and landscape management. Ambio 27 170-174. 

Nitrate and Nitrite. Nitrate is usually present in trace quantities in surface waters but occasionally occurs in high concentrations in some groundwaters. If present in excessive amounts, it can contribute to the illness infant methemoglobinemia. Nitrate is an essential nutrient for many photosynthetic autotrophs. Nitrite is an intermediate in the reduction of nitrate as well as in the oxidation of ammonia it is also used as a corrosion inhibitor in some industrial processes. 

SI 1998/2138 Nitrate Sensitive Areas (Amendments) (No. 2) Regulations SI 1998/2746 The Groundwater Regulations... 

Nitrite (or compounds at the same or lower oxidation level) is produced microbiologically from nitrate, and may then react with the substrate to produce stable end products. The production of nitrite is the sole metabolic function of the bacteria and, in view of concern over the presence of nitrate in groundwater, the following possible environmental significance of these or analogous reactions should not be overlooked ... 

Simultaneous degradation of 2,4- and 2,6-DNT has been achieved in a fluidized-bed biofilm reactor (Lendemann et al. 1998) that was successfully operated with contaminated groundwater containing 2- and 4-nitrotoluenes and 2,4- and 2,6-DNTs. The nitrite that was produced during degradation was recovered as nitrate. 

Most corrosion processes in copper and copper alloys generally start at the surface layer of the metal or alloy. When exposed to the atmosphere at ambient temperature, the surface reacts with oxygen, water, carbon dioxide, and air pollutants in buried objects the surface layer reacts with the components of the soil and with soil pollutants. In either case it gradually acquires a more or less thick patina under which the metallic core of an object may remain substantially unchanged. At particular sites, however, the corrosion processes may penetrate beyond the surface, and buried objects in particular may become severely corroded. At times, only extremely small remains of the original metal or alloy may be left underneath the corrosion layers. Very small amounts of active ions in the soil, such as chloride and nitrate under moist conditions, for example, may result, first in the corrosion of the surface layer and eventually, of the entire object. The process usually starts when surface atoms of the metal react with, say, chloride ions in the groundwater and form compounds of copper and chlorine, mainly cuprous chloride, cupric chloride, and/or hydrated cupric chloride. 

Porter W P, Jaeger J W and Carlson I H (1999). Endocrine, immune, and behavioral effects of aldicarp (carbamate), atrazine (triazine) and nitrate (fertilizer) mixtures at groundwater concentrations . Toxicology and Industrial Health, 15,133-150. 

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