Establishment and analytical quality control of laboratories for Hg determination in biological and geological samples in the Amazon, Brazil

RESUMO

During the past 20 years significant amounts of HG have been released in the Amazonian environment due to goldmining activities. Several Brazilian and foreign research groups have been studying the region, always facing difficulties regarding preservation and transfer of the collected samples from the field to the analytical laboratories. Aiming to solve these problems two high quality Hg analytical laboratories were established in the region. One is located at Fundação Esperança (FE, Santarém, PA), a medical assitance foundation and the other at the Universidade Federal de Rondônia (UNIR), Porto Velho, RO. Their main equipament is Atomic absorption spectrophotometers for Hg analysis (Klow Injection Mercury System-FIAS 400 with automatic samples-AS90-Perkin Elmer) and a microwave oven digestion system (MDS-2000-CEM). Technicians and researchers were trained in several aspects like environmental and human sampling, digestion methods and Hg analysis for biotic and abiotic materials. This training as well as the installation of the mentioned laboratories were the responsibility of the Universidade Federal do Rio de Janeiro (UFRJ). Intercalibration exercices were performed between several laboratories Environmental Medicine of Odense University (Denmark), Centre de Toxicologie du Québec, Canada and Occupational Health Sciences (Health-Canada). In the last 18 months the FE laboratory joined the Hg urine analysis intercalibration program of the Laboratory of the Centre of Toxicology in Québec, Canada, reaching accurate results. To date both Amazonian laboratories are able to analyze several different materials Sediment, soil, fish, urine, hair and blood. The FE laboratory is becoming more specialized in human samples such as urine, blood and hair, wile UNIR laboratory deals with environmental samples such as fish, sediment and soil.