Toxicity testing of wastewater and sewage sludge by biosensors, bioassays and chemical analysis

Abstract

Toxicity testing has grown steadily in recent years, being a useful tool in environmental risk assessment. This review highlights different bioassays and recently developed biosensors based on acute toxicity measurements. Emphasis is placed on the use of combined approaches involving chemical analysis for the characterization and identification of complex toxic wastewater effluents and sewage sludge. Fractionation schemes that combine sample preparation and chemical analysis with biological measurements are presented and reviewed. Bioassay-directed chemical-analysis protocols involve solid phase extraction (SPE), followed by chromatographic techniques, such as liquid chromatography-mass spectrometry (LC-MS) or gas chromatography-mass spectrometry (GC-MS). Toxicity testing is carried out by either bioluminescence inhibition methods or a whole-cell bacterial biosensor. Other biological toxicity tests are also reviewed. Examples of using different bacterial acute toxicity assays are presented for phenols, polyethoxylate surfactants, linear alkyl benzene sulphonates (LASs), naphthalene and benzene sulphonates, polycyclic aromatic hydrocarbons (PAHs), pesticides and pharmaceutical drugs.