Acid-volatile sulfide (AVS) has been proposed as the primary normalization phase for the development of sediment quality criteria for certain cationic metals. This study was designed to assist in this development by providing necessary field data on the relationships among season, AVS concentrations, and zinc bioavailability and toxicity in freshwater sediments. Zinc was spiked into uncontaminated sediments collected from a local pond, creating five simultaneously extracted metal (SEM) concentrations ranging from 0.8 to 12.0 mol/g dry weight. The spiked sediments were transferred to 4-L plastic trays, returned to the bottom of the pond, and sampled on five dates during 1993-1994. Results revealed a pronounced increase in AVS concentration with increasing zinc concentration. Acid-volatile sulfide concentrations in zinc-spiked sediments displayed only minor seasonal variation but were lowest in surficial (0-2 cm) sediments. Acid-volatile sulfide concentrations always exceeded SEM concentrations at Յ6.0 mol SEM/g; only at 12.0 mol SEM/g did SEM/AVS ratios exceed 1.0. Zinc was rarely detected in pore water at any treatment and never at concentrations which should have posed a hazard to benthic macroinvertebrates. No substantial effect on colonization of zinc-spiked sediments by benthic macroinvertebrates was observed. Only oligochaetes (Naididae) were significantly reduced in abundance at the high zinc treatment, although reductions were occasionally evident for other taxa. Lack of noteworthy pore-water zinc concentrations and lack of associated, ecologically meaningful effects were attributed to the increase in AVS levels observed with increasing SEM zinc sediment concentration. The increases in AVS theoretically resulted from a replacement of natural iron and manganese sulfides with the more stable zinc sulfide complex.

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Abstract-Acid-volatile sulfide (AVS) has been proposed as the primary normalization phase for the development of sediment quality criteria for certain cationic metals. This study was designed to assist in this development by providing necessary field data on the relationships among season, AVS concentrations, and zinc bioavailability and toxicity in freshwater sediments. Zinc was spiked into uncontaminated sediments collected from a local pond, creating five simultaneously extracted metal (SEM) concentrations ranging from 0.8 to 12.0 mol/g dry weight. The spiked sediments were transferred to 4-L plastic trays, returned to the bottom of the pond, and sampled on five dates during 1993-1994. Results revealed a pronounced increase in AVS concentration with increasing zinc concentration. Acid-volatile sulfide concentrations in zinc-spiked sediments displayed only minor seasonal variation but were lowest in surficial (0-2 cm) sediments. Acid-volatile sulfide concentrations always exceeded SEM concentrations at Յ6.0 mol SEM/g; only at 12.0 mol SEM/g did SEM/AVS ratios exceed 1.0. Zinc was rarely detected in pore water at any treatment and never at concentrations which should have posed a hazard to benthic macroinvertebrates. No substantial effect on colonization of zinc-spiked sediments by benthic macroinvertebrates was observed. Only oligochaetes (Naididae) were significantly reduced in abundance at the high zinc treatment, although reductions were occasionally evident for other taxa. Lack of noteworthy pore-water zinc concentrations and lack of associated, ecologically meaningful effects were attributed to the increase in AVS levels observed with increasing SEM zinc sediment concentration. The increases in AVS theoretically resulted from a replacement of natural iron and manganese sulfides with the more stable zinc sulfide complex.