Pm. Chapman et al., Ecotoxicology of metals in aquatic sediments: binding and release, bioavailability, risk assessment, and remediation, CAN J FISH, 55(10), 1998, pp. 2221-2243
Citations number
239
Categorie Soggetti
Aquatic Sciences
Journal title
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
Major metal-binding phases in the aerobic layer of sediments are iron and m
anganese oxyhydroxides (FeOOH and MnOOH) and particulate organic carbon (PO
C). The acid-volatile sulfide (AVS) model proposed for predicting nontoxici
ty from metals-contaminated sediments is only applicable to anaerobic sedim
ents. In other sediments, normalization by POC or FeOOH and MnOOH may be pr
edictive, but binding constants are not well understood. Metal mobilization
is enhanced by ligand complexation and oxidation of anaerobic sediments. F
ree metal ion is the most bioavailable species, but other labile metal spec
ies and nonchemical variables also determine metal bioavailability; biotic
site binding models have shown promise predicting toxicity for systems of d
iffering chemistry. Hazard identification and ecological risk assessment (E
RA) depend on determining bioavailability, from water (overlying, interstit
ial) and food, which can be done prospectively (e.g., normalized sediment c
hemistry, laboratory bioassays) or retrospectively (e.g., in situ bioassays
, field studies). ERA of sediment-bound metals requires primary emphasis on
toxicity and consideration of the three separate transformation processes
for metals in the aquatic environment, the differences between essential an
d nonessential metals, the complex interactions that control bioavailabilit
y, adaptation, which may occur relatively simply without appreciable cost t
o the organism, weight of evidence, and causality.