Md. Paine et al., LIMITED BIOAVAILABILITY OF SEDIMENT PAH NEAR AN ALUMINUM SMELTER - CONTAMINATION DOES NOT EQUAL EFFECTS, Environmental toxicology and chemistry, 15(11), 1996, pp. 2003-2018
A Sediment Quality Triad study involving synoptic measures of polycycl
ic aromatic hydrocarbon (PAH) contamination, toxicity, and resident co
mmunity (benthic infauna, crab) alteration was conducted to assess imp
acts from an aluminum smelter discharge. No sediment toxicity was obse
rved, despite extensive testing since 1988 on four test species. Evide
nce of effects on resident communities was minimal. Effects were nor e
xpected in areas >1 km from the smelter, because PAH concentrations ha
ve decreased with recent effluent improvements to below levels associa
ted with effects in other studies. However, concentrations within 1 km
of the smelter were high (maximum concentration was 10,000 mg/kg tota
l PAH, although most were <150 mg/kg). Based on the literature, those
concentrations should have had significant effects on toxicity test re
sponses and benthic communities. Because they did not, we conclude tha
t availability of sediment PAH was limited. Concentrations of parent P
AH and metabolites in Dungeness crab (Cancer magister) were also low,
supporting the hypothesis of limited bioavailability. Bioavailability
may be limited because much of the PAH is present as pitch or coal par
ticles. This study indicates that high contaminant concentrations may
not be associated with effects, if availability is limited.