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Numerous studies have shown growing information indicating the contribution of food to the dietary exposure of arsenic (As) through consumption of different food items in many different regions over the world. However, few review papers with regard to As in Sri Lankan foods are available in databases. Thus, a critical review and assessment of a number of local studies on total As concentrations has been made in rice, fish and fisheries products, vegetables, and other food products from Sri Lanka. From a limited comparison of freshwater fish with two marine species, the tuna and rays have substantially higher total As concentrations than all the freshwater species analyzed. One of the more important findings is that rice, the staple food of the country, is a major contributor to total As exposure of the population. Hence, based on the assessment of available data for total As levels in the various foods analyzed, it is suggested that a shift in a staple food diet of rice to one of maize and multi-cereal grains could lead to a reduction in total As exposure to the general population. Furthermore, important information gaps were identified such as a total lack of corresponding data for total As in Sri Lankan fruit crops, and a major one being the present lack of any information on the various inorganic and organic As species in local foods. Finally, some suggestions are made for giving guidance in agricultural practices which will lead to a reduction in As inputs to the local farmlands. This data compilation and assessment serves as an initial baseline for comparison with As results from future monitoring and research studies in Sri Lanka. [ABSTRACT FROM AUTHOR]

A design concept and supporting analysis are presented for a He-cooled fast reactor for the transmutation of spent nuclear fuel. Coated transuranic (TRU) fuel particles in a SiC matrix are used. The reactor operates subcritical (k ≤ 0.95), with a tokamak D-T fusion neutron source, to achieve >90% TRU burnup in repeated five-batch fuel cycles, fissions 1.1 tonnes/full-power year, and produces 700 MW( electric) net electrical power. The reactor design is based on nuclear, fuels, materials, and separations technologies being developed in the Generation-IV, Next Generation Nuclear Plant, and Advanced Fuel Cycle Initiative programs and similar international programs, and the fusion neutron source is based on the physics and technology supporting the ITER design. [ABSTRACT FROM AUTHOR]

Analyses of pesticide residues in sediments, water and biota of the Altata - Ensenada del Pabellon coastal lagoon system in Sinaloa, Mexico, showed the presence of organochlorine and organophosphorus compounds. For all the compounds analysed, concentrations in sediments were higher near the points of water discharge from ponds and drainage from the agricultural area. Among the organochlorines, total DDTs displayed the largest sedimentary reservoir, followed by total endosulfans and chlorpyrifos. In sediments, as well as in biota, pp'-DDT concentrations were lower than those of DDT metabolites, which confirms the reduction in the previous massive use of this compound in agriculture. Endosulfan is currently used in the region and endosulfan residues in lagoon sediments attained levels considered to be toxic to meiofauna, therefore constituting an ecological risk to lagoon ecosystems. There was a large sedimentary reservoir of chlorpyrifos but its ecotoxicological risk is difficult to assess due to lack of adequate comparative data. Nevertheless, concentrations of chlorpyrifos which approach acute toxic levels for shrimp were recorded in lagoon water. This suggests that drainage from agricultural fields during high runoff may, on occasion, cause mass mortality of shrimp and fish. Organophosphorus pesticides are widely regarded to degrade very rapidly in aquatic systems. Experimental research performed with 14C-labelled chlorpyrifos and parathion has shown that they may be stabilised for relatively long periods of time through sediment-water partitioning. This extension of their environmental half-lives increases their potential for impacting on coastal ecosystems. Since organophosphorus pesticides are highly toxic for aquatic organisms at concentrations generally lower than organochlorines, their presence in the lagoon water and sediment is a matter for much concern. The increased use of tropical coastal lagoons for shrimp and fish farming requires the implementation of environmental management practices to protect these ecosystems from the impact of agricultural activities. Environmental management aims to preserve the ecosystem integrity of these coastal lagoons and, through improving the water quality, to allow the development of aquaculture and reduce human exposure to pesticide residues in food. [ABSTRACT FROM AUTHOR]