Subaquatic sediments and flood plain soil are complex, making it difficult to predict the fate and bioavailability of the metals in these systems. Many metals are redox active or are chemically reactive, meaning that their speciation cannot be decoupled from the environmental conditions. This makes it difficult to predict the risk from metal contamination or the efficacy and permanence of a mitigation strategy in a particular sediment using bulk characterization methods. We use synchrotron X-ray spectroscopy to better understand metal speciation in those sediments, and then correlate that with observed measures of metal distribution in sediments, proxies of metal bioavailability, or the measured metal biouptake or toxicity of metals including, mercury, copper, silver, and gold. In all cases, differences in metal speciation could be used to explain the system response to metal inputs. But, in all cases the metal availability was also loosely correlated with the concentrations of “dissolved” metal in the system, so it is possible that Danny is actually right about what controls metal (and PAH) bioavailability in subaquatic sediments. More research is needed, of course.

Metal speciation matters: Stories of fate and bioavailability potential in subaquatic sediments

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.