Environmental Footprint of Wastewater Treatment: A Step Forward in the Use of Toxicological Tools

Abstract

The assessment of the actual impact of discharged wastewater on the whole ecosystem and, in turn, on human health requires the execution of bioassays. In effect, based on the chemical characterization alone, the synergistic/antagonistic effect of mixtures of pollutants is hardly estimable. The aim of this work was to evaluate the applicability of a battery of bioassays and to suggest a smart procedure for results representation. Two real wastewater treatment plants were submitted to analytical campaigns. Several baseline toxicity assays were conducted, together with tests for the determination of endocrine activity, genetic toxicity and carcinogenicity of wastewater. A “traffic light” model was adopted for an easy-to-understand visualization of the results. Although the legal prescriptions of chemical parameters are fully complied with, bioassays show that a certain biological activity still residues in the treated effluents. Moreover, influent and effluent responses are not always appreciably different. Some tests employing human cells were revealed to be only partially adequate for environmental applications. An interesting and helpful development of the present approach would consist in the estimation of biological equivalents of toxicity, as shown for the estrogenic compound 17-β-estradiol.

Beyond the Black Box of Life Cycle Assessment in the Wastewater Treatment Plants: Which Help from the Bioassays?

“…The scheme of the plant is depicted in Figure 2. A detailed description of the WWTPs and the main operational parameters are reported in [29,39].…”

“…Primary data include effluent characteristics (for the conventional environmental footprint method) as well as bioassay results (for alternative environmental footprint approach). Effluent properties include standard parameters (BOD, COD, TSS, N, P, and others) as well as metals, semimetals, and organic compounds (see Figure 5) [29,39]. The same composite samples, which were also subjected to chemical analyses, were subjected to eight bioassays in order to test organisms at various levels of the trophic chain and investigate various modes of action.…”

“…Since it is impossible to measure every pollutant (primary and secondary) present in an emission, non-targeted analyses have been receiving more attention, in an effort to describe these complex mixtures more accurately, while going beyond the lists of standards outlined in regulations and guidelines [23][24][25]. The execution of bioassays (possibly organized in batteries, including various modes of toxicity action, biological complexity systems, and trophic roles) has been increasingly proposed, which is even more significant [26][27][28][29][30][31][32]. Rather than focusing on a subset of known contaminants, this final strategy promotes the biological response by including both known and unknown chemicals in the mixture.…”

To spread or not to spread? Assessing the suitability of sewage sludge and other biogenic wastes for agriculture reuse

“…Indeed, several studies suggest that the limitations of the chemical “single substances” approach can be overcome by carrying out multi-tiered biological assays, which can directly and more accurately measure the impact of a stream [ [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] ]. More recently, the adoption of bioassays within the protocol for the evaluation of the environmental footprint of wastewater treatment plants was proposed [ [24] , [25] , [26] , [27] ]. Only bioassays, in fact, may be able to measure the actual effect of a matrix on the different components of the ecosystem, thus giving a more realistic answer to the question: is sludge (or another residue) reuse safe?…”

Evaluation of Toxicity and Genotoxicity of Concrete Cast with Steel Slags Using Higher Terrestrial Plants

“…Plant‐based assays are part of these analytical batteries and are often included because of their good correlations with other plant and animal systems, including humans (Reis et al, 2017). For these reasons, the results of such batteries have been combined for the construction of risk matrices (Marmiroli et al, 2022) and environmental footprint maps (Bertanza et al, 2021; Pedrazzani et al, 2020).…”