Recovery of benthic macrofauna from sewage sludge disposal in the New York Bight

The 12-Mile Dump Site Recovery Study (12MDSRS) was a multi-year, multi-disciplinary field study to monitor the recovery of the benthic ecosystem in the inner New York (NY) Bight following termination of sewage sludge disposal in 1987. Sewage sludge had been dumped at the 12-Mile Dump Site (12MDS) for over 60 yr. In the early 1980s, the 12MDS was receiving the largest volume of sewage sludge of any dump site in the world. Monthly sampling of sediments, benthic macrofauna, and other parameters was conducted for 18 mo during phased cessation of sludge disposal and 21 mo afterward at 3 sites considered to have varying degrees of sludge influence. We used a Before-After-Control-Impact (BACI) design in an attempt to factor out effects of background variability from the effect of termination of sludge disposal. The BACI analyses confirmed a sludge cessation effect for only some of the taxa that showed large increases in abundance after cessation. Non-metric multidimensional scaling (MDS) ordination indicated a shift in community structure at the most contaminated site towards that at the reference sites within 21 mo post cessation. Differences observed between the Pearson & Rosenberg model and the present study appear to be related to site-specific factors in the inner NY Bight. These factors facilitated the rapid reduction of sewage sludge constituents in surficial sediments after cessation.