Relationship between acid volatile sulfide and the toxicity of zinc, lead and copper in marine sediments

Abstract

It has been proposed that acid volatile sulfide (AVS) is an important sediment phase for determining the toxicity of certain trace metals. By evaluating the ratio of the molar quantities of simultaneously extracted metal (SEM) to AVS, the toxicity of metals to organisms in contact with sediment can be predicted. This study examines the role of AVS in predicting the toxicity of zinc, lead, and copper in marine sediments.Sediment samples were titrated with zinc, lead, and copper and subsequently analyzed for SEM, pore-water (PW) metal, and AVS retention. In most cases, metal was not detected in the pore waters until the AVS was exceeded, suggesting that AVS is an adequate measure of the metal-binding capacity of a sediment. The [SEMI-to-[AVS] ratios were calculated and toxicities predicted for each spiking concentration where [SEM]/[AVS] > 1. A 10-d, flow-through, acute bioassay using the marine polychaete Cupitellu cupitutu was conducted to examine the prediction of toxicity from the metal titrations and the bioassay sediment chemistry data. In most cases, mortalities occurred as predicted. AVS and the [SEMI-to-[AVS] ratio proved useful as predictors of toxicity for zinc, lead, and perhaps copper. Another tool for predicting metal toxicity in sediments may be the [PW]/LC50 value; in every case where this ratio was > 1, mortalities occurred.

Speciation of Trace Metals in Sediments

“…An often used single leaching procedure for sulfur and iron speciation is the acid volatile sulfide (AVS) determination using hydrochloric acid. The simultaneously extracted metal fraction has gained wide acceptance within the environmental community as a proxy for potential metal bioavailability (Casas and Crecelius, 1994), but comprises several possible species such as both Fe II and Fe III , or Cu I and Cu II phases (Simpson et al, 1998;Cooper and Morse, 1998). When the concentration of an element is controlled by the rate of release from the solids rather than by chemical equilibria, more sophisticated mechanismspecific leaching tests such as sequential extraction schemes are required for speciation assessment.…”

Predicting pollutant concentrations in the water column during dredging operations: Implications for sediment quality criteria

“…Associations between toxicity of sediments and the fractionation and speciation of metals have yielded good results, when the Acid Volatile Sulfide/Simultaneously Extractable Metals (AVS/SEM) model was developed (Ankley et al, 1996;Casas and Crecelius, 1994). However, environmental agencies hesitated to adopt the model as a reference for sediment quality criteria, because there was an ongoing and extensive discussion of the roles played by interstitial water concentrations (Lee et al, 2000) and organic matter (Besser et al, 2003) that were not taken into account by the AVS/SEM model.…”

Potential risks of metal toxicity in contaminated sediments of Deûle river in Northern France

“…It is worth noting that, as SEM exceeds slightly AVS in most cases, the remaining metals (corresponding to the difference: SEM − AVS) are either selectively bound with other compounds of sediments (including carbonates, oxides/hydroxides and organic matter) or are remobilized into the pore water. Based on [SEM − AVS] contents in sediments, several authors made reliable predictions on potential risks of trace metals in aquatic media [39,40,[68][69][70]. On this view, the evolution of both [SEM Me − AVS] and SEM versus interstitial water concentrations of metals measured at different sediment depths in Deûle river (Fig.…”