Top down arsenic uncertainty measurement in water and sediments from Guarapiranga dam (Brazil)

Total arsenic measurements assessment regarding legal threshold demands more than average and standard deviation approach. In this way, analytical measurement uncertainty evaluation was conducted in order to comply with legal requirements and to allow the balance of arsenic in both water and sediment compartments. A top-down approach for measurement uncertainties was applied to evaluate arsenic concentrations in water and sediments from Guarapiranga dam (Sao Paulo, Brazil). Laboratory quality control and arsenic interlaboratory tests data were used in this approach to estimate the uncertainties associated with the methodology.