A Heavy Metal Exposure Risk assessment Model to Migratory Birds and Human in Burullus Lake, Egypt

Abstract

Studying migratory birds wintering stopover areas has a global concern. The contamination of heavy metals is one of the serious threats to birds in the wetland ecosystem. In the present study, heavy metal exposure risk to birds in Burullus Lake was assessed. The concentrations of Cr, Ni, Pb, Cd, and Co in water, plant, and fish were determined in 10 bird habitats. A heavy metals' exposure risk assessment model to migratory birds in Burullus Lake had been done. It showed that small waders, represented by dunlin, are exposed to higher doses and risk than the waterfowls, represented by mallard. Evaluation of this risk to migratory birds could not be done using water exposure doses only, but food exposure including plant and fish must be included. It is a priority to perform more efforts to reduce serious contamination with Co and Ni. The risk for fish feeders can be summarized according to the following order: Co > Ni > Cd > Pb > Cr, while the risk for plant feeders is: Co > Ni > Cr > Cd > Pb. The health risk of heavy metal exposures was calculated using Target Hazard Quotient (THQ) and Hazard index (HI). Results showed that THQs for all metals were below the standard (<1), while HI values were lower than one except for Co and Cd. HI for these two metals are considered an appreciable hazard risk to human health. Therefore, it is recommended to analyze the heavy metal risk on a temporal basis.