PARENT SESSION
PM11 - Sediment Toxicology
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P316) Toxicity and contaminants distribution in sediments collected close to a Brazilian sewage outfall.

Abessa, Denis^*,1, Carr, Robert^2,3, Sousa, Eduinetty¹, Hortellani, Marcos⁴, Sarkis, Jorge⁴, ¹ Instituto Oceanográfico da USP, São Paulo, SP² Texas A&M University, Corpus Christi, TX, USA³ US Geological Survey, Corpus Christi, TX, USA⁴ IPEN, São Paulo, SP, Brazil

ABSTRACT- The sewage outfall from Santos is operating since the early 80's. However the effects of its discharges to the environment were not previously evaluated. In this study, seasonal variations in the whole sediment toxicity and in the distribution of surfactants and metals in sediments were investigated. Toxicity was evaluated by the 10-day amphipod testing, metals were analysed by AAS and anionic tensoatives were estimated by the MBAS method. Acute toxicity was observed in the campaigns made in summer and winter 1998 and summer 1999, whereas no toxicity to the amphipod Tiburonella viscana was detected in winter 1999 and summer 2000. Regarding to the metals, concentrations did not vary significantly for sediments of 3 stations. Sediments from station 1, situated close to the sewage diffusers, presented the higher concentrations, excepting during the summer 2000, when station 5 showed the higher levels of metal contamination for all elements analysed. The surfactant concentrations in the sediments tended to be higher in the summer 1999, decreasing to the winter 1999 and increasing again in the summer 2000.

Key words: sediments, toxicity, metals, surfactants