Investigation of effects of exposure to sewage sludge on terrestrial molluscs through analysis of changes in population structure, tissue accumulation, histology and proteomics

Endocrine disrupting compounds (EDCs) together with potentially toxic metals (PTMs), are present in large amounts in sewage sludge which was used as a tool to expose terrestrial molluscs to environmental concentrations of these pollutants. Pastures fertilised with sewage sludge had significantly fewer adult slugs collected per replicate (C: 58.4; T: 26.2; S.E.D. 0.14; p<.05) and eggs (C: 16.6; T: 9.1; S.E.D. 0.17; p<0.05). No differences with treatment, in tissue concentrations of EDCs or PTMs or in hepatopancreas or gonad structure, were detected. However, hepatopancreatic proteins (cyclophilin, paramyosin and trypsin) were significantly altered (p<0.01). In a laboratory study, exposure, via feed, to 0x (Control), 1x (T1), 10x (T2) or 110x (T3) the environmental dose of sludge extract resulted in a dose-related increase in mean mortality rates (relative to controls) in adult slugs (Deroceras reticulatum). Exposure for 3 weeks induced no measurable differences in tissue pollutant concentrations or hepatopancreas or gonad histology. Fewer slug eggs exposed to sludge and/or dehydration (2x2; 10 eggs/replicate); hatched following sludge exposure (C hydrated 64.5%;T hydrated 24.5%; p<0.05; S.E.D. 2.169; C dehydrated 48.9%; T dehydrated 17.4%; p<0.05; S.E.D. 4.256) but not following dehydration. There was no significant interaction between sludge exposure and dehydration but survival was lowest in animals exposed to both. Slug behaviour was affected by exposure to sludge, including increasing avoidance and huddling behaviours. The results indicate that terrestrial molluscs may be used as invertebrate sentinels to assess the effects of ECD and PTM exposure.EThOS - Electronic Theses Online ServiceGBUnited Kingdo