Ganga-Meghna-Bramhaputra basin is one of the major arsenic-contaminated hotspot in the world. To assess the level of severity of arsenic contamination, concentrations of arsenic in irrigation water, soil, rice, wheat, common vegetables, and pulses, intensively cultivated and consumed by the people of highly arsenic affected Nadia district, West Bengal, India, were investigated. Results revealed that the arsenic-contaminated irrigation water (0.318-0.643 mg l⁻¹) and soil (5.70-9.71 mg kg⁻¹) considerably influenced in the accumulation of arsenic in rice, pulses, and vegetables in the study area. Arsenic concentrations of irrigation water samples were many folds higher than the WHO recommended permissible limit for drinking water (0.01 mg l⁻¹) and FAO permissible limit for irrigation water (0.10 mg l⁻¹). But, the levels of arsenic in soil were lower than the reported global average of 10.0 mg kg⁻¹ and was much below the EU recommended maximum acceptable limit for agricultural soil (20.0 mg kg⁻¹). The total arsenic concentrations in the studied samples ranged from <0.0003 to 1.02 mg kg⁻¹. The highest and lowest mean arsenic concentrations (milligrams per kilogram) were found in potato (0.654) and in turmeric (0.003), respectively. Higher mean arsenic concentrations (milligrams per kilogram) were observed in Boro rice grain (0.451), arum (0.407), amaranth (0.372), radish (0.344), Aman rice grain (0.334), lady's finger (0.301), cauliflower (0.293), and Brinjal (0.279). Apart from a few potato samples, arsenic concentrations in the studied crop samples, including rice grain samples were found not to exceed the food hygiene concentration limit (1.0 mg kg⁻¹). Thus, the present study reveals that rice, wheat, vegetables, and pulses grown in the study area are safe for consumption, for now. But, the arsenic accumulation in the crops should be monitored periodically as the level of arsenic toxicity in the study area is increasing day by day.

This study was carried out to assess the overall water quality and identify major variables affecting the deep groundwater quality in Kathmandu Valley, Nepal. Forty-two deep wells were sampled during premonsoon and monsoon seasons in 2007 and analyzed for the major physicochemical variables. The water quality variables such as NH ₄ ⁺ -N, Fe, Pb, As, and Cd at most of the sampling locations exceeded the World Health Organization guideline levels for drinking water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in deep groundwater quality. Factor analysis indentified six major factors explaining 74.77% of the total variance in water quality; and the major variations are related with the degree of groundwater mineralization, decomposition of organic matter, and reduction of groundwater environment. The water quality of deep groundwater is influenced by the natural hydrogeochemical environment. The wells are broadly divided into two major groups based on the similar groundwater characteristics using cluster analysis. Results show that water quality of deep groundwater does not vary significantly as a function of season.

This study aimed at determining the water quality of River Sirimon and River Kongoni, Ewaso Ng'iro North Basin, Kenya. Water quality analysis of these two rivers was done for a period of 5 months between November 2005 and February 2006. Portable Palintest equipment was used for the chemical analysis. The study established that there were sulphates concentrations of 22 mgL⁻¹ in the Kongoni River water associated with the use of commercial fertilisers as compared to mean values of 7 mgL⁻¹ along Sirimon River; phosphate concentrations were 1.3 mgL⁻¹ in Kongoni and 0.15 mgL⁻¹ in Sirimon and salinity 3 mgL⁻¹ in Kongoni and 0.47 mgL⁻¹ in Sirimon. On average, mean nitrates concentrations of 1.7 mgL⁻¹ were recorded for Kongoni River, which were higher than those recorded for Sirimon River (0.033 mgL⁻¹). These concentration levels were however within the standard levels set by WHO for example 50 mgL⁻¹ for nitrates (WHO 2008). River Kongoni has two major irrigated horticultural farms across it which were likely polluting the river during the time of this study.