The Arsenic Contamination of Drinking and Groundwaters in Bangladesh: Featuring Biogeochemical Aspects and Implications on Public Health

Arsenic is a widespread contaminant of drinking and groundwaters in the world. Even if these contaminations have a geogenic origin, they often are exacerbated by anthropogenic activities. This is particularly true for the Bengal delta. Millions of people in Bangladesh are consuming drinking water with arsenic concentrations ≥ 50 µg/L. Their drinking water supply is based on groundwaters extracted by pumping wells, which were part of a well-drilling program by the United Nations. The intention was to provide the people with groundwater instead of surface water due to its critical hygienic conditions. Unfortunately, many wells extract the groundwater at depths where arsenic concentrations are highest. Arsenic is being dissolved from the aquifer by biogeochemical processes that are fueled by the presence of high amounts of organics in the Bengal delta sediments. This problem was not encountered at the time due to a lack of chemical analyses of the waters

Determination of trace amounts of nitrate in potassium chloride-extracts by HPLC with ultra-violet-detection

A method is presented that allows the determination of trace amounts of nitrate in I M potassium chloride extracts of environmental soil samples from Northern Europe. To avoid the interference of bromine ions on the evaluation of the nitrate peak, 50 muL of a 50mg/L nitrate standard solution are added to a 5mL soil extract. This makes sure that the overall nitrate concentration in the spike is >500 mug/L which allows an exact and reliable determination of the nitrate concentration. Analyses of the soil extracts are carried out by anion-exchange HPLC with ultra-violet detection at lambda = 210nm using 0.1 M KCl as eluent. Concentrations down to 25 mug/L of nitrate can be analyzed