The toxicity of pesticides and organics to Mysid shrimps can be predicted from Daphnia spp. toxicity data

Lack of marine toxicity data for most pesticides currently in use severely restricts the ability of environmental scientists to predict the impacts of discharges to the marine environment. This paper reviews the available aquatic toxicity data for a total of 18 pesticides and an additional 19 non-pesticide organics. Eleven of these compounds were chosen because of their use for external parasite control on sheep, the remaining compounds were chosen based on the availability of Mysid shrimp toxicity data. The sheep ectoparasiticides were chosen as other work, at the Wool Research Organisation of New Zealand (WRONZ), has been assessing the toxicity of woolscouring wastewater. A high correlation (R2=0.945, n=9) was found between published Mysidopsis bahia (96 h LC50) toxicity data and those of Daphnia spp. (48 h EC50), after transforming the data to log μmol/l. Further extending the database to include non-pesticide organics did not adversely affect this correlation (R2=0.941, n=28) or alter the slope of the correlation curve. These high correlation coefficients indicate that acute Daphnia spp. toxicity data may be able to be used to predict Mysid shrimp (M. bahia) sensitivities, thus providing a risk assessment tool for use in marine or estuarine situations. It was also apparent that Mysids are generally more sensitive to organics that Daphnia.