Acid‐volatile sulfide (AVS) in a seasonally anoxic mesotrophic lake: Seasonal and spatial changes in sediment AVS

Abstract

Acid‐volatile sulfide (AVS) is an operational definition for the sulfides removed from sediment by cold acid extraction. It has been proposed that this fraction could be used as an indicator of divalent metal toxicity (e.g., Cd, Ni, Hg), as it increases the metal‐binding capacity of sediments and hence renders metals unavailable to biota. Before AVS can be used as a predictive tool in freshwater systems, we must develop a better understanding of the impact of seasonal turnover events on its geochemistry. An in‐depth study of spatial and temporal variation in AVS concentrations in a seasonally anoxic mesotrophic lake is presented. Comparisons are made to AVS in other lakes, with reference to its utilization as a sediment toxicity parameter. Results indicate that AVS increases during anoxic periods and that lake morphology is important due to sediment focusing. Seasonal variations in AVS concentration were observed that may change the potential toxicity of metals in freshwater sediments.

Comprehensive assessment of heavy metal contamination in sediment of the Pearl River Estuary and adjacent shelf

“…However, several limitations are also evident which may restrict the application of AVS-SEM method. Firstly, AVS can vary when sediments are oxygenated, leading to the variation in the toxicity of the metals presented in the sediment over time (Howard and Evans, 1993;USEPA, 2004). Another problem with AVS as an indicator of sediment toxicity is determining when and where the AVS should be measured and how it can be applied to the water body as a whole (Howard and Evans, 1993).…”

“…Firstly, AVS can vary when sediments are oxygenated, leading to the variation in the toxicity of the metals presented in the sediment over time (Howard and Evans, 1993;USEPA, 2004). Another problem with AVS as an indicator of sediment toxicity is determining when and where the AVS should be measured and how it can be applied to the water body as a whole (Howard and Evans, 1993). Moreover, it may overestimate the adverse effects of heavy metals if the difference of SEM-AVS is larger than zero, since it does not take into account the importance of other binding phases that will also limit the bioavailability of a metal (i.e.…”

A field study of metal toxicity and accumulation by benthic invertebrates; implications for the acid‐volatile sulfide (AVS) model

“…The large seasonal changes in AVS concentrations reported to occur in some lakes have been attributed to fluctuations in either temperature or hypolimnetic oxygen concentrations (Howard and Evans 1993). Temperature is thought to indirectly affect AVS concentrations through its influence on primary productivity and sediment microbial activity .…”

Seasonal Variation of Acid Volatile Sulfide and Simultaneously Extracted Metals in Sediment Cores from the Pearl River Estuary

“…However, one potential limitation of using AVS as an indicator for sediment toxicity is determining when and where AVS should be measured and how it can be applied to the water body as a whole (Howard and Evans, 1993). Simpson et al (2012) highlighted the importance of considering the temporal natural of AVS in sediments and the need to monitor the presence of this phase and its influence on the bioavailability of metals in surface sediments.…”

“…In experiments with laboratory and field sediments, when the concentrations of AVS in sediments exceeded those of the metals that were simultaneously extracted in the AVS procedure (i.e., simultaneously extracted metals [SEM]), no adverse biological effects due to metals were found (Allen et al, 1993;Berry et al, 2004). An SEM/AVS molar ratio greater than one means that more metals are present in the sediment relative to AVS, and these unbound metals have the potential to be much more bioavailable than those bound to sulfides (Berry et al, 1996;van Griethuysen et al, 2004).However, one potential limitation of using AVS as an indicator for sediment toxicity is determining when and where AVS should be measured and how it can be applied to the water body as a whole (Howard and Evans, 1993). Simpson et al (2012) highlighted the importance of considering the temporal natural of AVS in sediments and the need to monitor the presence of this phase and its influence on the bioavailability of metals in surface sediments.…”