Toxicity evaluation of metal plating wastewater employing the Microtox® assay: A comparison with cladocerans and fish

Abstract

The relative sensitivity of the Microtox assay is closely related to the type of toxicant, and hence its utility in biomonitoring effluents is better evaluated on a case-by-case basis. The Microtox assay, employing the marine bacterium Vibrio fischeri, was evaluated for its applicability in monitoring metal plating wastewater for toxicity. The results of the Microtox assay after 5, 15, and 30 min of exposure, were compared with data obtained from conventional whole effluent toxicity testing (WET) methods that employed Daphnia magna, Ceriodaphnia dubia, and the fathead minnow (Pimephales promelas). The Microtox assay produced notably comparable EC50 values to the LC50 values of the acute fathead minnow toxicity test (< 0.5 order of difference). The Spearman's rank correlation analyses showed that the bacterial assay, regardless of exposure duration, correlated better with the acute fish than the daphnid results (p < 0.05). These observations were consistent to other studies conducted with inorganic contaminants. The relative sensitivity of the 30-min Microtox assay was within the range of the two frequently used acute daphnid/fish toxicity tests. In conclusion, the Microtox assay correlated well with the acute fathead minnow data and is well suited for toxicity monitoring for these types of industrial wastes.

Toxicity of Some Pesticides, Heavy Metals and Their Mixtures to Vibrio fischeri Bacteria and Daphnia magna: Comparative Study

“…To better understanding the toxicological profile of environmental toxicants, the impacts of such toxicants should preferably measured by organisms representing different trophic levels (Choi and Meier, 2001). In the majority of aquatic ecosystems, the most important trophic level in terms of energy flow and nutrient cycling is the bacteria.…”

“…Several investigators (e.g., Gä lli et al, 1994;Teodorovic et al, 2009;Choi and Meier, 2001;Sponza and Kuscu, 2011;Lopez-Roldan et al, 2012) , 2012). The 3 OP insecticides tested in the present study had extremely lower EC50 values (Table 1).…”

“…Therefore, the toxicological profile of an environmental toxicant is better understood when its impact is measured by organisms that represent different trophic levels (Choi and Meier, 2001). Several investigators (e.g., Choi and Meier, 2001;Ferrari and Ferard, 2005;Qu et al, 2013;Kokkali and van Delft, 2014) have recommended the user to select a battery of assays and biomonitors for a complete chemical toxicity assessment of an aqueous source considering selection of species from different trophic levels depending on the target matrix. …”

Sensitivity of bacterial vs. acute Daphnia magna toxicity tests to metals

“…In addition, it is commonly used for comparative studies on sensitivity of other ecotoxicological methods, including bacterial tests [22][23][24].…”

“…Heavy metals, commonly present in poorly treated waste waters, contaminated surface waters and sediments, are easily identified as major toxicants in toxicity evaluation [22][23][24][25][26] using Daphnia magna acute tests, as this species is among the most sensitive standard test species to heavy metals (ECOTOX database.…”