Within the context of the Water Framework Directive, the need to identify new monitoring tools in support of the traditional chemical monitoring process is emerging. Chemical characterization by itself does not provide specific biological information about potential hazards to organisms, in particular when facing cocktails of contaminants. Therefore, ecotoxicity tests can represent a useful tool supporting the chemical information. In the present work, the value of ecotoxicity tests as an effect-based tool for monitoring freshwater and sediment quality of the south-western basin of Lake Como (Northern Italy) was evaluated, assessing the potential risk of pollutants. Results obtained from D. magna toxicity tests showed a temporal variation of toxic response in relation to the variability of organic micropollutant load characteristics of urban rivers. Sediment ecotoxicity test data showed the spatial variability of the sediments’ contamination within the lake, confirmed by chemical analysis of two classes of pollutants (dichlorodiphenyltrichloroethane (DDT) and polychlorobiphenyls (PCB)). The observed effects on organisms in laboratory tests caused by a mixture of almost unknown chemicals underline the importance of integrating effect-based tools into monitoring efforts.

https://www.mdpi.com/2076-3298/1/1/92/pdf

An ecotoxicological approach to assess the environmental quality of freshwater basins: a possible implementation of the EU Water Framework Directive

/pdf/toxicity-of-water-and-sediment-from-guarapiranga-billings-445comir8h.pdf

Toxicity of water and sediment from Guarapiranga, Billings and Paiva Castro reservoirs, in Metropolitan Region of São Paulo-SP

Relationships between sediment toxicity and sediment chemistry were evaluated for 98 samples collected from seven metropolitan study areas across the United States. Sediment-toxicity tests were conducted with the amphipod Hyalella azteca (28 day exposures) and with the midge Chironomus dilutus (10 day exposures). Overall, 33 % of the samples were toxic to amphipods and 12 % of the samples were toxic to midge based on comparisons with reference conditions within each study area. Significant correlations were observed between toxicity end points and sediment concentrations of trace elements, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphe- nyls (PCBs), or organochlorine (OC) pesticides; however, these correlations were typically weak, and contaminant concentrations were usually below sediment-toxicity thresholds. Concentrations of the pyrethroid bifenthrin exceeded an estimated threshold of 0.49 ng/g (at 1 % total organic carbon) in 14 % of the samples. Of the samples that exceeded this bifenthrin toxicity threshold, 79 % were toxic to amphipods compared with 25 % toxicity for the samples below this threshold. Application of mean probable effect concentration quotients (PECQs) based on measures of groups of contaminants (trace elements, total PAHs, total PCBs, OC pesticides, and pyrethroid pesticides (bifenthrin in particular)) improved the correct classification of samples as toxic or not toxic to amphipods compared with measures of individual groups of contaminants.

Contaminants in Stream Sediments From Seven United States Metropolitan Areas: Part II—Sediment Toxicity to the Amphipod Hyalella azteca and the Midge Chironomus dilutus Nile E. KembleDouglas K. HardestyChristopher G. Ingersoll • James L. KunzPaul K. SibleyDaniel L. CalhounRobert J. Gilliom • Kathryn M. KuivilaLisa H. NowellPatrick W. Moran

D. L. Calhoun

Papers