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

ROSSO, JUAN JOSE; SCHENONE, NAHUEL FRANCISCO; PÉREZ-CARRERA, ALEJO; FERNÁNDEZ CIRELLI, ALICIA

ENVIRONMENTAL GEOCHEMISTRY AND HEALTH

SPRINGER

Lugar: Berlin; Año: 2013 vol. 35 p. 201 - 214

0269-4042

Arsenic (As) may occur in surface freshwater ecosystems as a consequence of both naturalcontamination and anthropogenic activities. In this paper, As concentrations in muscle samples of 10 fish species, sediments and surface water from three naturally contaminated rivers in a central region of Argentina are reported. The study area is one of the largest regions in the world with high As concentrations in groundwater. However, information of As in freshwater ecosystems and associated biota is scarce. An extensive spatial variability of As concentrations in water and sediments of sampled ecosystems was observed. Geochemical indices indicated that sedimentsranged from mostly unpolluted to strongly polluted. The concentration of As in sediments averaged 6.58l g/g ranging from 0.23 to 59.53l g/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 195l g/L. The average concentration of As in fish was 1.76l g/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 fish species seemed to be able to regulate theuptake of this metalloid, the concentration of As in the large catfish Rhamdia quelen mostly followed the concentration of As in abiotic compartments. The erratic pattern of As concentrations in fish and sediments regardless of the invariable high levels in surface waters suggests the existence of complex biogeochemical processes behind the distribution  patterns of As in these naturally contaminated ecosystems.