Heavy Metals in Tissues of Blue Crabs Callinectes danae from a Subtropical Protected Estuary Influenced by Mining Residues.

This short note aims to report in detail a preliminary assessment of the concentrations of Cd, Hg and Pb in tissues of blue crabs Callinectes danae collected from the Cananéia-Iguape-Peruíbe estuarine complex (CIP), in the South of São Paulo State coast, Brazil. In October 2014, blue crabs were collected from CIP. Tissues were removed by dissection and metal determination was performed by GF-AAS and CV-AAS. According to statistical analysis, Pb and Cd concentrations in gills were significantly higher than those found in muscles and hepatopancreas, respectively. There were no significant differences in Hg concentrations between samples. Cd, Hg and Pb concentrations in gills and hepatopancreas were lower than those reported in a previous study performed at CIP. However, Cd concentration in hepatopancreas was higher than the Brazilian limit for consumption and new efforts to monitor Cd concentrations in C. danae tissues must be performed.

Levels of metals and toxicity in sediments from a Ramsar site influenced by former mining activities.

This study aimed to evaluate the sediment quality in a Ramsar site located in the Southeast Brazil, by using several lines of evidence (LOEs). Chemical and sedimentological analyses, ecotoxicological tests, and whole-sediment Toxicity Identification Evaluation (TIE) were performed. The sediments were predominantly composed of fine sands and muds. Higher concentrations of metals in the sediments collected close to Iguape were observed; however according to the SEM/AVS analyses, most sediments should not be toxic and the potentially toxic samples could occur along the whole channel. In fact, sediments of most stations were toxic in at least one survey. The PCA revealed associations between mud, metals and toxicity. Acutely toxic sediments presented Pb concentrations above the threshold effect levels, while chronic toxicity seemed to be influenced also by SEM. The most contaminated and toxic areas are not necessarily those located close to the primary sources, but are actually those with finer sediments. Toxicity Identification and Evaluation (TIE) showed that metals and ammonia were responsible for the toxicity. The results suggest that metals from former mining areas located at the upper Ribeira de Iguape River are transported to the Cananéia Iguape Peruíbe Protected Area and accumulate in the sediments at potentially toxic levels. The location of muddy and more contaminated sediments appears to move along the estuary, accompanying the displacement of the maximum turbidity zone, which, in turn, depends on seasonal freshwater inputs. The results also showed that using several lines of evidences to asses contamination in a protected area provides reliable information to subsidise further actions to control the sources of contaminants.

Metals and arsenic in fish from a Ramsar site under past and present human pressures: Consumption risk factors to the local population.

The risk of metals and As in seafood for traditional populations living in a Marine Protected Areas (MPA) is seldom assessed, although the risk of human exposure to contaminants is one of the indicators associated with the socioeconomic goals of MPAs. The current study aimed to estimate the potential risk of some metals (Cd, Pb, and Zn) and arsenic (As) for human health through the ingestion of fish locally harvested in a Ramsar site, the Cananéia-Iguape-Peruíbe Environmental Protected Area (APA-CIP). Previous studies showed environmental impacts in this area due to former mining activities and urbanization. Cathorops spixii, a catfish largely consumed by the local population, was collected along the estuary in three seasons with different rain regimes. Metals and As loads in muscle tissue were quantified and it was estimated (i) the target hazard quotient (THQ) and (ii) the daily intake (EDI) for metals and As, (iii) the cancer risk (CRisk) only for As, and (iv) the number of eligible meals per month. Cd, Pb, and As were found at concentrations above action levels for human consumption. Depending on the level of exposure of the local population, the consumption of C. spixii may pose risk to human health. Highest THQs were estimated for fish collected in sites closer to the main contamination sources in the APA-CIP, i.e. the mouth of Ribeira de Iguape River (P1) and the city of Cananéia (P4, P5, and P6). Arsenic showed high levels of cancer risk, although restricted to the area close to the city. The exposure of the local population to metal and As contaminated seafood cannot be disregarded in environmental studies and management of the APA-CIP.