Comparison of different extraction procedures for organic-fraction toxicity testing of urban sewages

n-Hexane microextraction, C18 solid-phase extraction (SPE) columns, liquid-liquid extraction, rotaevaporation, Kuderna-Danish concentration and Semi-Permeable Membrane Devices with triolein (SPMD), were used to extract the organic (lipophilic) fraction of 22 municipal effluent samples. The fractions were tested on a three-bioassay battery consisting of the short-term Daphnia magna immobilisation test, the microplate Chlorella vulgaris growth inhibition test, and the in vitro cytotoxicity test with the fish line RTG-2. Additionally, replicated samples were spiked with naphtalene, 3,4-dichloroaniline or hexachlorobenzene. C18 SPE columns and SPMD were the most efficient methods for extracting the spiked compounds. These extraction procedures also were the most sensitive to detect the presence of toxic substances in the unspiked municipal wastes. Twenty-two, 9.7 and 2.1 percent of the extracts were toxic in one, two or the three bioassays respectively. Daphnia magna showed in most cases the highest sensitivity. However, one sample (representing 6.25% of the C18 SPE column extracts) was not toxic for daphnids but toxic for algae and for the fish cell line, confirming the need of a bioassay battery. For municipal wastes, usually rich in ammonia, nitrites, etc.;the specific toxicity testing of the organic (lipophilic) fraction, (the Organic-Fraction Toxicity (OFT) testing) can be more valuable for the identification of non-expected highly toxic pollutants than Whole Effluent Toxicity Testing (WET). OFT testing provide a cost-effective method for the hazard assessment of municipal effluents, which can be useful for the screening detection of micropollutants. n-Hexane microextraction, C18 solid-phase extraction (SPE) columns, liquid-liquid extraction, rotaevaporation, Kuderna-Danish concentration and Semi-Permeable Membrane Devices with triolein (SPMD), were used to extract the organic (lipophilic) fraction of 22 municipal effluent samples. The fractions were tested on a three-bioassay battery consisting of the short-term Daphnia magna immobilisation test, the microplate Chlorella vulgaris growth inhibition test, and the in vitro cytotoxicity test with the fish line RTG-2. Additionally, replicated samples were spiked with naphtalene, 3,4-dichloroaniline or hexachlorobenzene. C18 SPE columns and SPMD were the most efficient methods for extracting the spiked compounds. These extraction procedures also were the most sensitive to detect the presence of toxic substances in the unspiked municipal wastes. Twenty-two, 9.7 and 2.1 percent of the extracts were toxic in one, two or the three bioassays respectively. Daphnia magna showed in most cases the highest sensitivity. However, one sample (representing 6.25% of the C18 SPE column extracts) was not toxic for daphnids but toxic for algae and for the fish cell line, confirming the need of a bioassay battery. For municipal wastes, usually rich in ammonia, nitrites, etc.;the specific toxicity testing of the organic (lipophilic) fraction, (the Organic-Fraction Toxicity (OFT) testing) can be more valuable for the identification of non-expected highly toxic pollutants than Whole Effluent Toxicity Testing (WET). OFT testing provide a cost-effective method for the hazard assessment of municipal effluents, which can be useful for the screening detection of micropollutants.

Bibliographic Details

Main Authors:	Pablos Chi, Victoria, Férnandez, C., Garcia-Hortigüela, P., Valdovinos, C., Tarazona, J. V.
Format:	artículo biblioteca
Language:	English
Published:	Taylor & Francis 1999
Subjects:	Municipal effluents, Organic micropollutants, Chemical extraction techniques, SPE columns, Triolein SPMD, Toxicity detection,
Online Access:	http://hdl.handle.net/20.500.12792/3272 http://hdl.handle.net/10261/290502
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