SynopsisOxygen uptake of Pseudomonas putida was employed for the rapid screening of toxicants in water. Oxygen uptake was measured over a 10 minute period at constant temperature by means of a biological oxygen monitoring system connected to a potentiometric recorder. Sublethal concentrations of selected chemicals inhibited or stimulated oxygen uptake. A P. putida growth inhibition test proved more sensitive to most individual chemicals than the oxygen uptake assay, but yields results only after some 7 hours. Industrial emuent in low concentrations and domestic wastewater, stimulated both oxygen uptake and growth of P. putida.Higher concentrations of industrial effluent and a laboratory mixture of selected toxicants inhibited both growth and oxygen uptake at equal levels of sensitivity. Sensitivity compared favourably with that of other rapid bioassays, and various toxicants were detected at concentrations well below those allowed in industrial emuents. Since the P . putida oxygen uptake assay is relatively sensitive, simple, economical and exceptionally fast, it should prove useful for the rapid testing of many wastewaters and even excessive contamination of drinking-water supplies while it may serve a valuable purpose as part of a battery of bioassays containing slower tests.
A number of aquatic toxicity tests have been established for South African use, which include fish and Daphnia lethality tests, microbiotests, and short-term chronic tests. Studies on effluents and surface waters showed that all the tests have a viable role to play in water quality management. The most advantageous use of the tests is in battery form, so that tests can complement each other. The fish and Daphnia lethality tests, and algal growth inhibition test are recommended for regulatory and management purposes of effluents. If receiving water is used for drinking water purposes, the Ames Salmonella mutagenicity and toad embryo teratogenicity tests should be included in the battery of tests. Some of the rapid microbiotests, e.g. the protozoan oxygen uptake test, bacterial growth test and enzyme tests, could be valuable screening tools to identify and categorize toxic effluents.
ABSTRACT:We examined the possibility of adapting the LuminoTox, a recently-commercialized bioanalytical testing procedure initially developed for aqueous samples, to assess the toxic potential of sediments. This portable fluorescent biosensor uses photosynthetic enzyme complexes (PECs) to rapidly measure photosynthetic efficiency. LuminoTox testing of 14 CRM (Certified Reference Material) sediments was first undertaken with (1) a ''solid phase assay'' (Lum-SPA) in which PECs are in intimate contact with sediment slurries for a 15 min exposure period and (2) an elutriate assay (Lum-ELU) in which PECs are exposed for 15 min to sediment water elutriates. CRM sediment toxicity data were then compared with those generated with the Microtox Solid Phase Assay (Mic-SPA). A significant correlation (P < 0.05) was shown to exist between Lum-SPA and Mic-SPA, indicating that both tests display a similar toxicity response pattern for CRM sediments having differing contaminant profiles. The sediment elutriate Lum-ELU assay displayed toxicity responses (i.e. measurable IC 20 s) for eight of the 14 CRM sediments, suggesting that it is capable of determining the presence of sediment contaminants that are readily soluble in an aqueous elutriate. Lum-SPA and Mic-SPA bioassays were further conducted on 12 natural freshwater sediments and their toxicity responses were more weakly, yet significantly, correlated. Finally, Lum-SPA testing undertaken with increasing mixtures of kaolin clay confirmed that its toxicity responses, in a manner similar to those reported for the Mic-SPA assay, are also subject to the influence of grain size. While further studies will be required to more fully understand the relationship between Lum-SPA assay responses and the physicochemical makeup of sediments (e.g., grain size, combined presence of natural and anthropogenic contaminants), these preliminary results suggest that LuminoTox testing could be a useful screen to assess the toxic potential of solid media.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.