Alternate Title

Impact on and Recovery of Experimental Macrobenthic Communities Exposed to Pentachlorophenol


Recovery of macrobenthic animal communities in sand-filled aquaria was deter· mined 7 weeks after a 5-week exposure to 55 μglℓ. pentachlorophenol. The communities developed from planktonic larvae in flowing estuarine water continuously supplied during treatment and recovery. Significantly fewer (α= 0.05) individuals and species occurred in contaminated aquaria than in control aquaria immediately after exposure to pentachlorophenol. Numbers of arthropods, chordates, echinoderms, and mollusks were decreased; annelids and coelenterates were not affected. Seven weeks after exposure was discontinued, total numbers of individuals and species in previously contaminated and control aquaria no longer differed. The dominant echinoderm, Leptosynapta inhaerens, reduced numerically in contaminated aquaria at 5 weeks, increased in number not significantly different from the control at 12 weeks. However, there were some differences among species in previously contaminated aquaria and the control that could be attributed to the toxicant. Numbers of Galathowenia sp., the dominant annelid at 12 weeks and not collected at 5 weeks, were lower in previously contaminated aquaria than in control aquaria. The dominant mollusk, Laevicardium mortoni, did not recover after it was reduced in abundance by exposure to PCP. Major differences in community structure between 5 and 12 weeks were not toxicant related, however, and possibly represent natural succession. These consisted of reduced numbers of amphipods, Corophium acherusicum, and tunicates, Molgula manhattensis, at 12 weeks in both control and previously contaminated aquaria.