The effects of bioturbation on sediment AVS, SEM, and SEM/AVS ratios
- Roy F. Weston, Inc., Edison, NJ (United States)
- Rutgers Univ., New Brunswick, NJ (United States)
- Environmental Protection Agency, Edison, NJ (United States)
Acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) were measured at three depths during a 3 x 4 factorial experiment (tubificid density and metal concentration) to assess the effects of bioturbation on the bioaccumulation of Cd and Ni by larval Fundulus heteroclitus. Intact sediment cores were inoculated with three densities of tubificids (0, 4,800, and 48,000/m{sup 2}). Larval fish were exposed for 15 days. AVS and SEM concentrations were measured at depths of 0--1 cm, 2.5--3.5 cm, and 5.5--6.5 cm. AVS concentrations ranged from below detection to 65 {micro}mol/g (dry wt). There was a significant difference with AVS with worm density and with depth. AVS concentrations in the 0--1 cm depth were significantly less than the other depths. The highest worm density chambers` AVS concentrations were ranked lowest. Bioturbation may have reduced AVS concentrations in the surficial layers resulting in higher SEM/AVS ratios. Observed sediment bioturbation included the feeding actions of the tubificds and larval fish, as well as fish disturbance. There was no significant difference between tubificid densities for SEM concentrations for Cd (P = 0.329) or Ni (P = 0.088). SEM/AVS ratios ranged from < 0.1 to 16.8, with the highest values at the 0--1 cm depth. The use of SEM/AVS ratios in determining the potential toxicity of a sediment ignores the spatial variability within a sediment profile. Larger SEM/AVS ratios at surface sediment layers indicates increased metal exposure potential for demersal fish and benthic invertebrates. Due to the observed effects of bioturbation, its role in contaminant release from sediments needs to be considered to gain an accurate understanding of in situ and laboratory bioavailability and bioaccumulation of contaminants.
- OSTI ID:
- 455286
- Report Number(s):
- CONF-961149--
- Country of Publication:
- United States
- Language:
- English
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