Porphyrin levels in excreta of sea birds of the Chilean coasts as nondestructive biomarker of exposure to environmental pollutants

In this preliminary study on sea birds we propose the use of porphyrins in excreta as a biomarker of exposure to contaminants. Samples of excreta were obtained from colonies of brown pelicans (Pelecanus occidentalis thagus), neotropic cormorants (Phalacrocorax olivaceus), and kelp gulls (Larus domin icanus) in three areas of the south coast of Chile with different human imp act (Tubul, Talcahuano, and Valdivia). They were analyzed for porphyrin con tent (copro-, uro-, and protoporphyrins and total porphyrins) by a rapid fl uorimetric method and by HPLC, The main outcomes of the study were: (a) kel p gulls and neotropic cormorants living in areas with high human impact sho wed a clear capacity to accumulate and eliminate porphyrins in the excreta; (b) species-related accumulation capacities are likely, as shown by the di fferent levels found in different species living in the same area; (c) the porphyrin profile obtained by fluorimetry and HPLC showed a higher percenta ge of protoporphyrin than the other porphyrins; (d) although the fluorimetr ic method of Grandchamp is semiquantitative, it was found to be sensitive e nough to detect differences in samples from field studies. The positive res ults of this preliminary study make it possible to propose this nondestruct ive method for a variety of field applications.