Superfund Research Program

A Combined Bioassay-Chemical Fractionation Scheme for the Determination of Toxic Chemicals in Sediments from the St. Lawrence River

Project Leader: Patrick W. O'Keefe (Wadsworth Center, New York State Department of Health)
Grant Number: P42ES004913
Funding Period: 1995 - 2000

Project-Specific Links

Final Progress Reports

Year:   1999 

Data on the quantitative recovery of the six polar aromatic compounds (oxyPAHs) identified in aluminum plant sediments were improved by using deuterated analogs of three of the compounds (fluorenone, anthraquinone and benz(a)anthracene-7,12-dione) as internal standards. These deuterated compounds were synthesized by published procedures. It was then found that recoveries of native oxyPAHs spiked into control sediments at a concentration of 60 ppb varied from 46 to 107% when the deuterated analogs were used as injection standards. The total concentration of the six compounds in the contaminated sediment used for the study was 51 ppm.

When the brine shrimp bioassay experiments described in the 1998-1999 progress report were repeated there was considerable mortality in the controls (> 30%). Mortality in the controls was reduced to less than 10% by (a) using a different strain of brine shrimp, (b) culturing the shrimp in water containing several inorganic salts in addition to sea salt and (c) feeding the shrimp with a heat-denatured algal suspension during culturing. When shrimp cultured by the revised protocol were exposed to extracts from the contaminated sediment and fractions from these extracts, the relative order of toxicity of the extracts and fractions was generally similar to that found previously. The highest toxicity (LD50 12 ppm), expressed as sediment equivalents, was found with a mixture of the fractions containing PAHs (F2) and oxyPAHs (F3). This LD50 was lower than the LD50 values for the individual fractions (1138 and 292 ppm for F2 and F3 respectively). The result suggests that the oxyPAHs strongly potentiate the toxicity of the PAHs. Furthermore, the F2/F3 mixture was more toxic than the extract (LD50 68 ppm), suggesting that antagonistic compounds present in the extract were removed in the silica gel fractionation step. When the six compounds were tested individually it was found that benzanthrone had the most potent toxicity (LC50 0.024 ppm) followed by benz(a)anthracene-7,12-dione (0.21 ppm), fluorenone (1.46 ppm) and carbazole (> 4 ppm). Anthraquinone and 9-anthracenecarbonitrile showed no evidence of toxicity.