Concentration of arsenic in water, sediments and fish species from naturally contaminated rivers

J. ROSSO; N. SCHENONE; A. PéREZ CARRERA; A. FERNáNDEZ CIRELLI

Ciudad Autónoma de Buenos Aires

Taller; El arsénico como factor limitante en la producción agrícolo-ganadera; 2011

Centro de Estudios Transdisciplinarios del Agua

Arsenic (As) may occur in surface freshwater ecosystems as a consequence of both naturalcontamination and anthropogenic activities. As in edible tissues of 10 fish species, sedimentsand surface water of three naturally contaminated rivers in a central region of Argentina arereported. The study area is one of the largest regions in the world with high As concentrations in groundwater, however information of As in fresh water is scarce. In water and sediments of the sampled rivers As concentrations showed high spatial variability. Geochemical indices indicated that sediments ranged from mostly unpolluted to strong polluted. The concentration of As in sediments averaged 6.58 ìg/g ranging from 0.23 ìg/g to 59.53 ìg/g. Arsenic in sediments barely followed (r = 0.361; p = 0.118) the level of contamination of water. All rivers showed high concentrations of As in surface waters, ranging from 55 to 195 ìg/L. The concentration of As in water differed significantly (p =0.004) among sampled rivers. The average concentration of As in edible tissues of fish was 1.76 ìg/g. The level of contamination with As differed significantly between species. Moreover, the level of bioaccumulation of As in fish species related to the concentration of As in water and sediments also differed between species. Whilst some seemed to be able to regulate the uptake of this metalloid, the concentration of As in the large catfish Rhamdia quelen mostly followed the concentration of As in abiotic compartments. The suitability of species for biomonitoring programs and the risk of consuming fish according to WHO/FAOrecommendations are discussed.