Ecological risk assessment of copper and cadmium in surface waters of Chesapeake Bay watershed

Abstract

Abstract-This ecological risk assessment was designed to characterize risk of copper and cadmium exposure in the Chesapeake Bay watershed by comparing the probability distributions of environmental exposure concentrations with the probability distributions of species response data determined from laboratory studies. The overlap of these distributions was a measure of risk to aquatic life. Dissolved copper and cadmium exposure data were available from six primary data sources covering 102 stations in 18 basins in the Chesapeake Bay watershed from 1985 through 1996. Highest environmental concentrations of copper (based on 90th percentiles) were reported in the Chesapeake and Delaware (C and D) Canal, Choptank River, Middle River, and Potomac River; the lowest concentrations of copper were reported in the lower and middle mainstem Chesapeake Bay and Nanticoke River. Based on the calculation of 90th percentiles, cadmium concentrations were highest in the C and D Canal, Potomac River, Upper Chesapeake Bay, and West Chesapeake watershed. Lowest environmental concentrations of cadmium were reported in the lower and middle mainstem Chesapeake Bay and Susquehanna River. The ecological effects data used for this risk assessment were derived primarily from acute copper and cadmium laboratory toxicity tests conducted in both fresh water and salt water; chronic data were much more limited. The 10th percentile (concentration protecting 90% of the species) for all species derived from the freshwater acute copper toxicity database was 8

Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment

“…where, i is the rank of a species in the data series and n is the total number of species examined (Hall et al, 1998;Schuler et al, 2008). The SSD curve was constructed using the mean toxicity (or the logarithmic value) as the x-axis and the cumulative probability as the y-axis.…”

Toxicity Reference Values and Tissue Residue Criteria for Protecting Avian Wildlife Exposed to Methylmercury in China

“…SSD is a statistical distribution representing the variation in sensitivity of species to a contaminant, and can be developed by a statistical or empirical distribution function of response for a sample of species ( Posthuma et al 2002 ) . This method has been used to assess risks to aquatic organisms and for deriving water quality criteria (WQC) for protecting aquatic species ( Caldwell et al 2008 ;Hall et al 1998 ;Solomon et al 1996 ;Stephan et al 1985 ) . However, because data on the toxicity of contaminants to wildlife are often insuf fi cient, the SSD approach to assess wildlife risks has not often been applied.…”

Characterizing ecological risk for polycyclic aromatic hydrocarbons in water from Lake Taihu, China

“…In the present study, the impact of parameter uncertainty was quantified by probability distribution functions. The probability distributions of exposure and toxicity concentrations are commonly well fitted by log-normal or log-logistic distributions (Hall et al 1998;Wagner and Løkke 1991;Meng and Wu 2010). However, an appropriate probabilistic distribution function should be assigned to the exposure concentrations and toxicity data depending on the availability and quality of the data sets; accordingly, the probabilistic distribution types should be selected on a case-by-case basis.…”