Autor(es):
Paixão, Eleonora 
; Machado, Ausenda ; Caeiro, Sandra ; Dias, Carlos Matias
Data: 2012
Identificador Persistente: http://hdl.handle.net/10400.18/1259
Origem: Repositório Científico do Instituto Nacional de Saúde
Assunto(s): Determinantes da Saúde e da Doença; Estuarine Sedimentary Environment; Risk Exposure Assessment
Descrição
Introduction: Previous environmental studies on Sado estuary indicated high concentrations of heavy metals (such as Cu, Zn, Ni, As, Cr, e Pb) on its sediments due to industrial contamination along with non-point anthropogenic sources.
Although considerable investigation has been done on environmental contamination assessment and its effects to ecological systems, in this particular geographical area no study relating the health effects due to exposure to heavy metals was ever conducted.
Thus an epidemiological study, was implemented in a small fisherman community living in Carrasqueira Village at Sado Estuary (exposed population) and in Vila Nova de Mil Fontes- VNMF (non exposed).The results to be presented reflect the analysis of occupational exposure comparing both populations.
Material and Methods: A cross-sectional study was designed and data was collected through an epidemiological questionnaire. Face to face interviews of selected individuals was done during June and July 2011. Participants, from all ages and sex, were selected by simple randomization, using the medical registrations lists of local Health Centers. Dimensions measured in the two groups included among others i) Exposure factors related to levels of contaminants, including socio-demographic, occupational, leisure habits and hobbies, ii) Route of contamination (with special attention to subsistence fishing and farming) and iii) Health effects.
To each respondent was required to describe the tasks inherent to their actual or past job. From this description indicators of a potential route exposure to contaminants were created. It was considered direct exposure (fishing inherent tasks); indirect exposure (agriculture inherent tasks), other routes of contamination (tasks with other sources of contamination such as painting). The absence of the previous exposures indicates that no relevant exposure existed.
Statistical analysis was performed using descriptive analysis and associations were tested using Chi-squared test. A 5% significance level was used in all the tests.
Results: A total of 202 participants were included in the study (102 in Carrasqueira and 100 in VNMF) and no significant differences were observed in age distribution (p=0.267), but there were significant differences in the educational (p<0.001) level and occupation (p<0.001).
Professions like fishers and agricultures are more likely to have higher risks of exposure to estuary river contaminants and were more common in Carrasqueira.
The participants of Carrasqueira reported a significant higher proportion of tasks inherent to their actual job, promoting direct (48.8%) and/or indirect (30.0%) exposure to contaminants (p<0.001 and p=0.006 respectively). There were no differences in the other routes of contamination (p=0.511). On the opposite VNMF participants were not exposed to any contaminant route. Similar results were found in the analysis of tasks in previous professions.
Also the period of time that was spent in the fishers and agricultures activities in Carrasqueira was higher than in VNMF (about 90% of individuals had more than 8 years of exposure, p<0.001).
Conclusions: On exposure epidemiological studies the selection of non exposed population is critical to avoid bias. The results obtained showed that VNMF population was a good selection since they differ from Carrasqueira in the exposure indicators.
