High cadmium residues observed during a pilot study in shorebirds and their prey downstream from the El Salvador copper mine, Chile

Beach deposit samples were collected in November 1981 and March 1982 from 5 sites along the 20 km beach area around Chanaral receiving copper mine tailings from the El Salvador copper mine, northern Chile, together with samples of Enteromorpha (sites 1, 2 and 4), limpets (Collisella sp.) snails (Littorina peruviana), sand crabs (Emerita analoga) and locos (Concholepas concholepas). The shorebirds, kelp gull (Lanes dominicanus), grey gull (Larus modestus), franklins gull (Larus pipixcan), whimbrel (Numerius hudsonicus), Sanderling (Calidris alba) and the oystercatcher (Haematopus ostralegus) were shot and their livers and stomachs removed immediately after collection. Cadmium and copper were determined for all samples using flameless atomic absorption analysis. Copper residues decreased from discharge site 1 to sampling station 3 but rose at station 4. Cadmium residues decreased from site 1 to site 2 but rose at sites 3 and 4 and at reference station 5. Possible reasons for these distributions are discussed. Copper residues in Enteromorpha decreased from sites 1 to 5. Cadmium and copper residues in crabs taken from the stomachs of L. modestus and H. ostralegus, and in snails taken from the stomach of N. hudsonicus were higher than residues found in fish from the stomach of L. dominicanus. E. analoga taken from birds and directly from the beach at site 4, had the highest cadmium concentrations. High cadmium residues in livers of L. modestus and N. hudsonicus from site 4 and whimbrels collected between sites 1 and 4 and site 5 were related to their infection of E. analoga. The observed cadmium concentrations were not consistent with current tailings discharged but possibly related to previous operations. Only whimbrel showed ill effects from the highest cadmium residues of 89.7 mg per kg when emaciation and necrosis of the liver was observed. The metal distributions in the birds are discussed.