Twenty two years of sewage sludge marine disposal monitoring in the Eastern Mediterranean Sea: Impact on sediment quality and infauna and the response to load reduction

Effects of sewage sludge disposal on sediments and infauna are presented in a unique long-term (22 years) data set from the Eastern Mediterranean. While organic carbon (C-org) and metals affected sediment quality in an area which size varied seasonally, the infauna exhibited seasonal boom and bust cycle. Metal concentrations declined following load reduction. However, C-org did not decrease and infaunal abundance, closely related to C-org, varied with changes in environmental forcing. Mild winters affected the infaunal populations at the heavily impacted stations, due to anoxic conditions. Planned cessation of disposal is estimated to reduce Corg and metal concentrations to pre-discharge levels. Yet the resettling biota is expected to differ significantly from the pre-discharge one and consist in large part of Erythraean non indigenous species. (C) 2016 Elsevier Ltd. All rights reserved.