Influence of Acid Volatile Sulfides and Metal Concentrations on Metal Partitioning in Contaminated Sediments

Abstract

The influence of acid volatile sulfide (AVS) on the partitioning of Cd, Ni, and Zn in porewater (PW) and sediment as reactive metals (SEM, simultaneously extracted metals) was investigated in laboratory microcosms. Two spiking procedures were compared, and the effects of vertical geochemical gradients and infaunal activity were evaluated. Sediments were spiked with a Cd-Ni-Zn mixture (0.06, 3, 7.5 µmol/g, respectively) containing four levels of AVS (0.5, 7.5, 15, 35 µmol/g). The results were compared to sediments spiked with four levels of Cd-Ni-Zn mixtures at one AVS concentration (7.5 µmol/g). A vertical redox gradient was generated in each treatment by an 18-d incubation with an oxidized water column. [AVS] in the surface sediments decreased by 65-95% due to oxidation during incubation; initial [AVS] was maintained at 0.5-7.5 cm depth. PW metal concentrations were correlated with [SEM -AVS] among all data. But PW metal concentrations were variable, causing the distribution coefficient, Kd pw (the ratio of [SEM] to PW metal concentrations) to vary by 2-3 orders of magnitude at a given [SEM -AVS]. One reason for the variability was that vertical profiles in PW metal concentrations appeared to be influenced by diffusion as well as [SEM -AVS]. The presence of animals appeared to enhance the diffusion of at least Zn. The generalization that PW metal concentrations are controlled by [SEM -AVS] is subject to some important qualifications if vertical gradients are complicated, metal concentrations vary, or equilibration times differ.

Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata

“…Use of high metal concentrations can shift the partitioning of metals from particles to porewater, lowering the partitioning coefficient (K d ; Luoma & Fisher 1997, J. S. Lee et al 2000. K d values determined in the present study were generally >10 4 for Ag and Cd, and > 2 × 10 3 for Zn, much greater than values observed in some of the previous studies (see also J. S. Lee et al 2000).…”

“…As found elsewhere, porewater metals were largely controlled by AVS and the pattern of the metal-AVS relationship was similar regardless of the sediment manipulation methods (J. S. Lee et al 2000). Use of low metal concentrations would shift the partitioning of metals to the particulate phase.…”

“…Manipulation of SEM to AVS by varying AVS concentrations allowed use of environmentally realistic metal concentrations in the present study (see also J. S. Lee et al 2000). As found elsewhere, porewater metals were largely controlled by AVS and the pattern of the metal-AVS relationship was similar regardless of the sediment manipulation methods (J. S. Lee et al 2000).…”

“…In addition, a short metal-sediment equilibration time is typically employed in many studies, which can enhance partitioning of metals to porewater relative to sediment particles (J. S. Lee et al 2000). Partitioning coefficients typically decrease as the metal-sediment equilibration time increases , Sibley et al 1996, Leonard et al 1999).…”

Studies on Water Pollution due to Toxic Metals in Ulhas River Flowing along the Dombivli City of Mumbai, India

“…The toxic heavy metals in aquatic environment are adsorbed onto particulate matter, although they can form free metal ions and soluble complexes that are available for uptake by biological organisms [14]. The metals associated with particulate material are also available for biological uptake [15] and are deposited in estuarine sediments [16]. Once deposited, binding by sulfides and/or iron hydroxides immobilizes trace metals until a change in redox or pH occurs [17,18].…”