High levels of polychlorinated biphenyls in tissues of Atlantic turtles stranded in the Canary Islands, Spain

Abstract

Polychlorinated biphenyls (PCBs 28, 31, 52, 101, 138, 153, 180, and 209) were measured in tissue samples (liver and fat) from 30 loggerhead turtles Caretta caretta, 1 green turtle Chelonia mydas, and 1 leatherback Dermochelys coriacea stranded on the coasts of the Canary Islands, trying to establish a possible relation between PCB concentrations and the lesions and causes of death. Tissues from these turtles contained higher levels of PCBs than those reported in turtles from other geographical regions. ∑PCB concentrations (1980 ± 5320 ng g−1 wet wt.) in the liver of loggerheads were higher than in the adipose tissue (450 ± 1700 ng g−1 wet wt.). Concentrations of PCB 209 in the liver (1200 ± 3120 ng g−1 wet wt.) of loggerheads and in the liver (530 ng g−1 wet wt.) and adipose tissue (500 ng g−1 wet wt.) of the leatherback were remarkable. Frequencies of detection of PCB 209 in the liver (15.5%) and adipose tissue (31%) were also remarkable. Cachexia was detected in 7 turtles (22%) and septicemia was diagnosed in 10 turtles (31%). Statistically, a positive correlation was detected between ∑PCBs concentration and cachexia. Poor physical condition, cachexia and/or septicaemia could explain the high levels of PCBs and tissue distribution. However, no histological lesions exclusively attributed to the acute effects of PCBs were described. The most prevalent histological lesions were ulcerative and purulent oesophagitis, purulent dermatitis, necrotizing enteritis, and granulomatous pneumonia. The bacteria most frequently isolated were Escherichia coli, Staphylococcus sp., and Aeromonas sp. Although immunosupression as a result of PCBs pollution has been described previously, other factors in this study, such as incidental fishing, nutritional status, and exposition to different micro-organisms, make it difficult to establish a clear association between PCB concentrations and causes of death.