Multiple Stable Isotope Analysis for the Assessment of Pollution Sources in a Mangrove Food Web

MAGDALENA MONFERRAN; DANIEL WUNDERLIN; MICHAEL ELLIOT; BARRY THORNTON; INDIA WEIDLE; ANDY MIDWOOD; CAROL-ANN CRAIG; HIULANA ARRIVABENE; IARA SOUZA; MARISA FERNANDES

Bruselas

Congreso; SETAC Europe 27th Annual Meeting; 2017

An estuary is a semi closed water body connecting freshwater with the sea, thus, having influence from both environments (Wolanski and Elliot, 2015). Metal transfer in the food web are dependent to the contamination source (surface water, sediment or particulate matter) and how this sources can affect the availability in the environment (acute or chronic). Understand the ecosystem structure and the trophic relations provide information about contaminants uptake and how much each trophic level are responsible for metal transfer until the top of trophic chain. To establish trophic levels in a food web, analysis of stable isotopes, such as carbon (δ13C) and nitrogen (δ15N) are useful tools reflecting the dietary history of an animal species (Bond, 2010). As metal contamination can originate from several sources, stable isotopes ratio are used to understanding the origin (source) of metals and metalloids in the food chain (Peterson and Fry, 1987; Ikemoto et al., 2008; Podio et al., 2013). Strontium ratio (87Sr/86Sr) primarily reflects the source bedrock geology. However, it can be strongly influenced by the marine signature and, in estuarine waters, can determine if the freshwater or the marine water dominated the inputs. Lead isotopes ratios (206Pb/207Pb and 208Pb/207Pb) have been used as anthropogenic tracers (Chow and Johnstone, 1965; Chow and Earl, 1970, 1972; Chow et al., 1973, 1975), and can be used as ?fingerprints? of environmental pollution (Komárek et al. 2008; Cheng and Hu 2010). Thus, the main goal of this study was to establish the structure of the mangrove food web by using isotopic signatures to assess the source and pathway of metal contamination in two mangrove ecosystem (Vitória Bay and Santa Cruz; Espírito Santo state, Brazil). We hypothesised that the evaluation of multiple stable isotopes in both the mangrove ecosystem and the Tubarão Harbour Complex should allow a pathway between industrial activity and differential pollution degrees observed to be determined, providing a reasonable tool-kit for the evaluation of other estuarine mangrove systems affected by anthropic pollution worldwide.