Studies on the cytolytic effects of seastar (Marthasterias glacialis) saponins and synthetic surfactants in the plaice Pleuronectes platessa

The toxic effects of Marthasterias glacialis (L.) saponins and synthetic surface-active agents were studied using the plaice Pleuronectes platessa L. as test animal. Solutions of M. glacialis saponins caused considerable, although non-uniform, damage to the gill epithelium, death resulting from a disturbance in the levels of oxygen, carbon dioxide, and sodium ions in the tissues and blood. Histological examination showed that solutions of the synthetic surfactants caused less damage to the gill epithelium than did the M. glacialis saponins. There was a linear relationship between the logarithm of the median haemolytic concentration and the logarithm of the median lethal concentration for the synthetic surfactants. Haemolytic inhibition experiments suggest that the M. glacialis saponins damage cell membranes by interacting with membrane cholesterol.     

Declining metal levels at Foundry Cove (Hudson River, New York): response to localized dredging of contaminated sediments

This study examines the effectiveness of remediating a well-recognized case of heavy metal pollution at Foundry Cove (FC), Hudson River, New York. This tidal freshwater marsh was polluted with battery-factory wastes (1953-1979) and dredged in 1994-1995. Eight years after remediation, dissolved and particulate metals (Cd, Co, Cu, Pb, Ni, and Ag) were found to be lower than levels in the lower Hudson near New York City. Levels of metals (Co, Ni, Cd) on suspended particles were comparatively high. Concentrations of surface sediment Cd throughout the marsh system remain high, but have decreased both in the dredged and undredged areas: Cd was 2.4-230mg/kg dw of sediment in 2005 vs. 109-1500mg/kg in the same area in 1983. The rate of tidal export of Cd from FC has decreased by >300-fold, suggesting that dredging successfully stemmed a major source of Cd to the Hudson River.