Lead pollution from waterfowl hunting in wetlands and rice fields in Argentina

ROMANO M; FERREYRA H; FERREYROA G; MOLINA FV; CASELLI A; BARBERIS I; BELDOMENICO P; UHART M

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 545 p. 104 - 113

0048-9697

The pollution of wetlands by lead derived from waterfowl hunting with lead shot was investigated. We determinedsoil pellet density and Pb concentration in soil, water and vegetation in natural wetlands and rice fieldsin central-eastern Santa Fe province, Argentina. Pellet density varied greatly among hunting sites (between5.5?141 pellets/m2) and pellets were present in some control sites. Soil Pb concentration in most hunting sites(approximately 10?20 mgkg−1) was not much higher than in control sites (~5?10 mgkg−1), with the exceptionof the sitewith highest pellet density,which also had a high Pb soil concentration. Inwater, on the other hand, Pbconcentration was similar in all sites (~4?7 μg L−1), both control and hunting, and higher than reference valuesfor aquatic media. Lead was also present in vegetation, including grasses and rice crops, in almost all cases. Mostsoil-collection sites were slightly acidic, and were frequently flooded. These results strongly suggest that metallicPb from spent shot is oxidized and dissolved due to wetland conditions. Thus, the pollutant is readily mobilized and distributed across allwetland areas, effectively homogenizing its concentration in locations with andwithouthunting activities. The replacement of lead by nontoxicmaterials in pellets appears to be the only effective way toprevent Pb pollution in wetlands.