Risk assessment in an estuarine environment: a case-study in the Sado estuary

• Author(s): Machado, Ausenda ; Paixão, Eleonora ; Caeiro, Sandra ; Dias, Carlos Matias
• Date: 2012
• Persistent ID: http://hdl.handle.net/10400.18/1086
• Origin: Repositório Científico do Instituto Nacional de Saúde
• Subject(s): Human Exposure Pathways; Health Effects; Contaminated Estuary; Determinantes da Saúde e da Doença
• Document Type: Conference Object
• Language: English

Description

Abstract publicado em: http://www.springerlink.com/content/45745132180p7215/ Introduction Previous environmental studies in the Sado estuary identified industrial and other anthropogenic contamination sources. Surrounding human populations have intense economic fishery and agriculture activities. Food usage previously characterized suggests exposure to estuarine products, farming products, and water in daily activities, as potential routes of contamination. In this geographical area no study relating the health effects due to exposure to heavy metals was ever conducted. Objective: To characterize exposure pathways to estuarine products and its potential health effects. Materials and Method A cross-sectional comparative study of residents in Carrasqueira (in Sado estuary) and residents in Vila Nova de Mil Fontes (VNMF), selected as the non-exposed population. VNMF sits near another river estuary with similar activities but no known contamination exposures. Simple random samples of individuals were selected in each study population from the National Health Service Lists. Face to face questionnaire data were collected at home and intended to characterize: 1) Health effects: diagnosed illnesses, reproductive history; 2) potential routes of exposure; 3) Potential routes of human contamination from the estuary. Statistical analysis included descriptive analysis and associations tests (Chi-squared test, alpha=0.05). The odds ratio of having an adverse outcome within Exposed and Non-Exposed groups was adjusted for possible confounders using the non conditional logistic regression. Potential confounders were investigated and included if they changed crude OR estimate in at least 10% after adjustment by the Mantel-Haenszel method. Results 202 participants of all ages were included. Participation rates were 62.5% in Carrasqueira and 48.3% in VNMF. Carrasqueira participants reported a significant higher proportion of professional tasks promoting direct (48.8%) and/or indirect (30.0%) exposure to contaminants (p<0.001 and p=0.006 respectively). Carrasqueira had higher period of time spent in fisher and agriculture activities than VNMF (90% of individuals had more than 8 years of exposure, p<0.001). A higher odd of having chronic heavy-metal related morbidity (OR= 1.91; CI95%: 1.01-3.64), and congenital anomalies (OR= 1.53; CI95%: 0.47- 4.92) were observed in Carrasqueira. Only age and years living in the local was retained as confounder in logistic regression, resulting in a 2,1 higher risk of having at least one of the diseases in Carrasqueira compared to VNMF (CI95%: 1.02-4.69). Conclusions Overall results indicate fragile but possible health effects of exposure to Sado estuary. Nevertheless, these results should be analyzed carefully since the outcomes in study are not specific and are based in small samples. Further studies should use bioindicators of exposure and outcome.