Empirical models for estimating the concentrations and exports of metals in rural rivers and streams

Cuthbert, Iain D.; Kalff, Jacob

doi:10.1007/bf00480547

Cited by 7 publications

(2 citation statements)

References 44 publications

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“…Figures 4 to 7 illustrate simulations of copper, nickel, lead, and zinc using the selected partitioning data in Table 7. As part of this project, a literature survey [22–44] (http://www.epa.gov/waterscience/cs/biotesting/) of reported partition coefficients for 33 metals was undertaken to obtain an impression of relative magnitude and variability. The results are included in the Supplementary Data ().…”

Section: Resultsmentioning

confidence: 99%

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Can the unit world model concept be applied to hazard assessment of both organic chemicals and metal ions?

Harvey

Mackay

Webster

2007

Environmental Toxicology and Chemistry

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A unit world model that has the potential to be used for the hazard assessment of both metal ions and organic chemicals is described and discussed, with an emphasis on the problems that arise when treating metal ions. It is based on the steady-state equilibrium criterion model that is designed to simulate the fate of organic chemicals in a 100,000-km(2) region and comprises four well-mixed compartments: Air, water, soil, and sediment. To be applicable to metal ions, modifications are required. The single soil and sediment layers should be replaced by two layers to accommodate aerobic and anaerobic conditions. The more complex and variable partitioning of metals resulting from dependence on pH, redox conditions, ionic oxidation state, and presence of sulfide also must be addressed, but preferably in a separate geochemical model, because these factors can result in nonlinearity. For metals, a dynamic as well as a steady-state model is desirable. It is shown that the resulting model can be applied to both organics and metals. Rather than seeking to apply the hazard criterion of persistence to metal ions, the model can be used to deduce a critical loading that results in a defined toxic end point, thus integrating the hazard criteria of persistence, toxicity, and possibly, bioaccumulation. This approach is applied illustratively to naphthalene as a typical organic substance and to four environmentally relevant metal ions. Results are discussed and recommendations made for further development. Specifically, the absence of metal degradation can result in large, steady-state quantities in soils and sediments corresponding to residence times of many centuries. Consequently, the dynamic calculations are more relevant for fate assessments of metals over a period of years, and more focus on the aquatic environment is justified.

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Section: Resultsmentioning

confidence: 99%

“… a Details of the literature search [22–44] (http://www.epa.gov/ost/cs/biotesting) are given in the Supplementary Data (). Metals selected for the calculation of a critical emission rate are in italics. …”

Section: Methodsmentioning

confidence: 99%