A postexposure feeding assay using the marine polychaete Neanthes arenaceodentata suitable for laboratory and in situ exposures.

This study examined the suitability for the use of the polychaetous annelid Neanthes arenaceodentata in a short-term sublethal bioassay based on postexposure feeding rate. Quantification of feeding rate was determined by an approximately 1-h feeding period to Artemia franciscana nauplii after a 48-h aqueous exposure. Both lethality and feeding rate were assessed after exposure to Cu and phenanthrene, with the Cu results being compared with those available from similar studies that used the polychaete Hediste diversicolor. Laboratory assessment on the effect of manipulating two common variables in estuarine environments (temperature and salinity) on postexposure feeding to both clean and Cu-spiked seawater samples was also conducted. The 48- and 96-h median lethal concentrations (LC50s) for Cu were 156 and 80 µg/L, respectively, whereas the 48-h median effective concentration (EC50) determined by feeding rate was 57 µg/L. The 48-h LC50 for phenanthrene was 2,224 µg/L, whereas the 48-h feeding rate EC50 was 345 µg/L (more sensitive by a factor of >6). The sensitivity of the postexposure feeding rate endpoint to two representative chemicals that are frequently elevated in contaminated sediments, in addition to rapid exposure time, ecological relevance, and relatively simple approach, suggest that this assay with N. arenaceodentata has potential for use as a tool for sublethal effects assessment, with particular promise for in situ applications. The utility of this assay in actual marine and estuarine sediments is being assessed in situ at several North American sediment sites, and will be reported in future publications.