ABSTRACT
An increased international awareness toward an assessment of the current status of aquatic environments and their protection has emerged as a result of multiple anthropogenic pressures, such as human population growth, progressive industrialization, and intensive agricultural practices. Initially, such an assessment was focused on the abiotic fractions of the environment, the dissolved fraction of the water column, and sediments. But the monitoring of dissolved contaminants is methodologically challenging, primarily because of limitations in analytical methods (capability of quanti cation), and also as a consequence of the typically low concentrations, not to mention the tendency for samples to become contaminated during collection or analysis.1 Furthermore, levels of dissolved contaminants are extremely variable and depend not only on season,2,3 but on factors such as tidal cycles4 and river ow5 as well. So a really accurate environmental assessment would require intensive, costly, and time-consuming monitoring programs.1,2 Finally, we need to mention that total dissolved contaminant concentrations are in fact not an accurate measure either of the fraction available to organisms or of that responsible for toxicity and bioaccumulation problems.
