The present study was undertaken to assess the impact of a candidate mosquito larvicide, spinosad (8, 17 and 33 μg L−1) on a field population of Daphnia magna under natural variations of water temperature and salinity, using Bti (0.16 and 0.50 μL L−1) as the reference larvicide. Microcosms (125 L) were placed in a shallow temporary marsh where D. magna was naturally present. The peak of salinity observed during the 21-day observation period may have been partly responsible for the decrease of daphnid population density in all the microcosms. It is also probably responsible for the absence of recovery in the microcosms treated with spinosad which caused a sharp decrease of D. magna abundance within the first two days following treatment whereas Bti had no effect. These results suggest that it may be difficult for a field population of daphnids to cope simultaneously with natural (water salinity and temperature) and anthropogenic (larvicides) stressors. Significant interaction between salinity and spinosad exposure impairs the recovery of a natural population of Daphnia magna

Freshwater ecosystems are negatively impacted by various pollutants, from agricultural, urban and industrial wastewater, with metals being one of the largest concerns. Moreover, freshwater ecosystems are often affected by alien species introductions that can modify habitats and trophic relationships. Accordingly, the threat posed by metals interacts with those by alien species, since the latter can accumulate and transfer these substances across the food web to higher trophic levels. How metals transfer within such communities is little studied. We analysed the concentration of 14 metals/metalloids (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Se, Zn, hereafter ‘metal(s)’) of eight fish and three crustacean species co-existing in the Arno River (Central Italy), most of which were alien. To assess the pathway of contaminants within the community, we coupled metal analysis with carbon and nitrogen stable isotope analysis derived from the same specimens. Crustaceans showed higher metal concentration than fish, except for Cd, Hg and Se that were higher in fish. We found evidence of trophic transfer for six metals (Cd, Cr, Hg, Mg, Se, Zn). Additionally, ontogenetic differences and differences among various fish tissues (muscle, liver, and gills) were found in metals concentration. Considerable biomagnification along the trophic chain was found for Hg, while other metals were found to biodilute. Using stable isotopes and Hg as a third diet tracer, we refined the estimations of consumed preys in the diet previously reconstructed with stable isotope mixing models. Alien species reach high biomass and can both survive to and accumulate high pollutants concentrations, potentially posing a risk for their predators and humans. A combined effect of environmental filtering and increased competition may potentially contribute to the disappearance of native species with lower tolerances.

A growing concern for contamination due to pharmaceutical compounds in groundwater is expanding globally.The β-blocker propranolol is a β-adrenoceptors antagonist commonly detected in European groundwater bodies. The effect of propranolol on stygobiotic species (obligate groundwater dweller species) is compelling in the framework of environmental risk assessment (ERA) of groundwater ecosystems. In fact, in Europe, ERA procedures for pharmaceuticals in groundwater are based on data obtained with surrogate surface water species. The use of surrogates has aroused some concern in the scientific arena since the first ERA guideline for groundwater was issued. We performed an ecotoxicological and a behavioural experiment with the stygobiotic crustacean species Diacyclops belgicus (Copepopda) to estimate a realistic value of the Predicted No Effect Concentration (PNEC) of propranolol for groundwater ecosystems and we compared this value with the PNEC estimated based on EU ERA procedures. The results of this study showed that i) presently, propranolol does not pose a risk to groundwater bodies in Europe at the concentrations shown in this study and ii) the PNEC of propranolol estimated through the EU ERA procedures is very conservative and allows to adequately protect these delicate ecosystems and their dwelling fauna. The methodological approach and the results of this study represent a first contribution to the improvement of ERA of groundwater ecosystems.

A Fenton like advanced oxidation process (AOP) employing scrap zerovalent iron (SZVI) and hydrogen peroxide (H2O2) was studied for industrial textile wastewater treatment from a textile manufacturing plant located at Medellín, Colombia (South America). The wastewater effluent studied contains a mixture of organic compounds resistant to conventional treatments. The effect of initial pH and SZVI concentration and H2O2 concentration were studied by a response surface methodology (RSM) Box-Behnken design of experiment (BBD). The combined SZVI/H2O2 process led to reductions of 95% color, 76% of chemical oxygen demand (COD) and 71% of total organic carbon (TOC) at optimal operating conditions of pH = 3, SZVI = 2000 mg/L and [H2O2] = 24.5 mM. Molecular weight distribution measurement (MWD), ultraviolet–visible (UV–Vis) spectroscopy, HPLC, biodegradability and toxicity were used to characterize the pollutants after the treatment process finding that the resulting effluent was polluted mostly by low molecular weight carboxylic acids. A remarkable biodegradability enhancement of the effluent was evidenced by a BOD5/COD ratio increase from 0.22 to 0.4; also, the SZVI/H2O2 process successfully reduced the toxicity from 60% to 20% of dead A. Salina crustaceans.

The exponential production and use of plastics has generated increasing environmental release over the past decades, and microplastics (MPs) have been reported across all the oceans. Field studies have documented the occurrence of MPs in several species, but important knowledge gaps still remain. In the present study, we characterized the distribution of MPs in ten sediment-dwelling and epibenthic species representative of different habitat, feeding modes and trophic levels within the inner Oslofjord (Oslo, Norway), an area subjected to moderate anthropogenic pressures. Analysed species included fish, bivalves, echinoderms, crustaceans and polychaetes. MPs were present in all the species with a frequency up to 65% of positive individuals for some species. In most cases, 1 or 2 MPs were found per individual, but some organisms contained up to 7 particles. A total of 8 polymer typologies were identified, with PE and PP being the most common according to our extraction protocol. MP sizes ranged from 41 μm to lines as long as 9 mm. Our results indicate that occurrence of MPs in analysed biota is not influenced by organism habitat or trophic level, while characteristics and typology of polymers might be significantly affected by feeding mode of organisms.

The occurrence, spatial distribution and seasonal variation of 14 organophosphate esters (OPEs) were investigated in urban surface water (river and lake water) from July 2013 to June 2014 in Beijing, China. Sewage influent and effluent samples, as well as rainwater and road runoff samples were also analyzed as the potential sources of OPEs in surface water. Tris(2-chloro-1-methylethyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) were the most abundant OPEs with the average concentrations of 291 ng L⁻¹ and 219 ng L⁻¹, respectively. Relatively high concentrations of OPEs were detected in rivers located at southern and eastern urban of Beijing, which was probably attributed to the treated and untreated sewage discharge. Besides, higher levels of OPEs were observed in urban surface water in the summer, and the wet deposition (rainfall) was confirmed to be an important factor for this observation. Risk assessment showed low or medium risk of OPEs for the organisms (algae, crustacean and fish).

The purpose of this study was to assess the ecotoxic potential of a new zero-valent iron nanomaterial produced for the elimination of chlorinated pollutants at contaminated sites. Abiotic dechlorination through the newly developed nanoscale zero-valent iron material and its effects on dechlorinating bacteria were investigated in anaerobic batch and column experiments. The aged, i.e. oxidized, iron material was characterization with dynamic light scattering, transmission electron microscopy and energy dispersive x-ray analysis, x-ray diffractometry and cell-free reactive oxygen measurements. Furthermore, it was evaluated in aerobic ecotoxicological test systems with algae, crustacean, and fish, and also applied in a mechanism specific test for mutagenicity. The anaerobic column experiments showed co-occurrence of abiotic and biological dechlorination of the common groundwater contaminant perchloroethene. No prolonged toxicity of the nanomaterial (measured for up to 300 days) towards the investigated dechlorinating microorganism was observed. The nanomaterial has a flake like appearance and an inhomogeneous size distribution. The toxicity to crustacean and fish was calculated and the obtained EC50 values were 163 mg/L and 458 mg/L, respectively. The nanomaterial showed no mutagenicity. It physically interacted with algae, which had implications for further testing and the evaluation of the results. Thus, the newly developed iron nanomaterial was slightly toxic in its reduced state but no prolonged toxicity was recorded. The aquatic tests revealed a low toxicity with EC50 values ≥ 163 mg/L. These concentrations are unlikely to be reached in the aquatic environment. Hence, this nanomaterial is probably of no environmental concern not prohibiting its application for groundwater remediation.