Identification and assessment of ecotoxicological hazards attributable to pollutants in urban wet weather discharges

A multi-disciplinary approach based on chemical characterization of foreshore sediments, ecotoxicity assessment and statistical analyses for environmental monitoring of marine-coastal areas

The present work aims at providing a multi-disciplinary approach for environmental monitoring in marine-coastal areas. A monitoring campaign of 13 months (October 2022-October 2023) was carried out on sandy foreshore sediments (SFSs). The SFSs were analysed for potentially toxic elements (PTEs) and rare earth elements (REEs) content determination. In the investigated area, variable contamination trends were assessed through Friedman and Nemenyi tests. Further results also indicated the usefulness of statistical data elaboration in the identification of potential contamination sources. In fact, from Spearman test, significant positive correlations (between 0.650 and 0.981) were observed among PTEs of possible anthropogenic origin (such as Co, Cr, Cu, Pb, V, and Zn). For REEs, La and Nd showed strong correlations with Ce (0.909 and 0.920, respectively). The study also integrated luminescence inhibition (Aliivibrio fischeri), algal growth inhibition (Phaeodactylum tricornutum), and embryotoxicity assessment (Paracentrotus lividus) on sediment elutriates showing varying degrees of toxicity. Also these data were analysed through statistics in order to highlight possible correlations between contaminants and observed ecotoxicological effects on the involved bioindicators. The results outline an approach useful for more comprehensive monitoring of marine areas quality and identification of suitable environmental restoration strategies.

Pesticides in wastewater treatment plant effluents in the Yeongsan River Basin, Korea: Occurrence and environmental risk assessment

Pesticides are among the main drivers posing risks to aquatic environments, with effluents from wastewater treatment plants (WWTPs) serving as a major source. This study aimed to identify the primary pesticides for which there was a risk of release into aquatic environments through WWTP effluents, thereby enabling more effective contamination management in public water bodies. In this study, monitoring, risk assessment, and risk-based prioritization of 87 pesticides in effluents from three WWTPs in the Yeongsan River Basin, Korea, were conducted. A total of 59 pesticides were detected at concentrations from 0.852 ng/L to 82.044 μg/L and exhibited variable patterns across different WWTP locations. An environmental risk assessment based on the risk quotient (RQ) of individual pesticides identified 13 substances implicated in significant ecotoxicological risks, as they exceeded RQ values of 1 at least once. An optimized risk (RQf)-based prioritization, considering the frequency of the measured environmental concentration (MEC) exceeding the predicted environmental concentration (PNEC), was conducted to identify pesticides that potentially posed risks and thus should be managed as a priority. Four pesticides had an RQf value >1; metribuzin exhibited the highest RQf value of 4.951, followed by 3-phenoxybenzoic acid, atrazin-2-hydroxy, and atrazine. Additionally, five pesticides (terbuthylazine, methabenzthiazuron, diuron, thiacloprid, and fipronil) and another four pesticides (propazine, imidacloprid, hexaconazole, and hexazione) had RQf values >0.1 and > 0.01, respectively. By calculating the contributions of individual pesticides to the RQf of these mixtures (RQf, mix) based on the concentration addition model, it was determined that >95 % of the sum of RQf, mix was driven by the top seven pesticides. These findings highlight the importance of prioritizing pesticides for effective management of contamination sources.

Occurrence, distribution, and ecological risk of bisphenol analogues in marine ecosystem of urbanized coast and estuary

Bisphenol analogues are prevalent globally because of rampant usage and imprecise processing techniques, prompting alerts about environmental and health hazards. The method employed in this study by solid phase extraction (SPE) and liquid chromatography-tandem quadrupole mass spectrometer (LC-MS/MS) for both quantification and qualitative analysis of the bisphenol compounds in the surface water samples. The coastal and estuarine surface water of Port Dickson and Lukut ranges from 1.32 ng/L to 1890.51 ng/L of bisphenol analogues. BPF mean concentration at 1143.88 ng/L is the highest, followed by BPA and BPS at 59.01 ng/L and 10.96 ng/L, respectively. Based on RQm for bisphenol analogues, the highest for BPF at 2.49 (RQ > 1, high risk), followed by BPS at 0.12 (0.1 < RQ < 1, medium risk) and BPA at 0.09 (0.1 < RQ < 1, medium risk). The presence and current risk of bisphenols analogues should alert the possible water quality degradation soon.

The bioprospecting potential of Clusia fluminensis Planch. & Triana: a scoping review

Many biological activities are described for the Clusiaceae family. Clusia fluminensis, a species from Brazilian flora, is mainly employed for ornamental purposes. This review aimed to depict the current knowledge of C. fluminensis from a bioprospecting standpoint. "Clusia fluminensis" search term was applied in Scopus, Web of Science, PubMed and Bireme databases according to PRISMA-ScR statement. Selected papers on Phytochemistry or Bioactivity followed hand searching procedures. Bioactivity preclinical studies considered in vitro or in vivo biological systems, treated with plant extracts or isolated compounds. The outcomes were compared with standard or no treatment control groups. Critical appraisal of individual trials considered completeness in the research fields. Our results showed that 81% of the selected papers presented high level of completeness, 69% revealed phytochemical parameters and 31% biological applications of plant extracts and isolated compounds. Polyisoprenylated benzophenones, terpenoids, sterols and phenolic compounds were identified. Antiviral, insecticidal and snake antivenom activities were reported. In conclusion, the phytochemical data reinforce the reported activities. Potential applications in personal care, nutritional supplementation and pharmaceutical, food, chemical or textile industries were also identified. Toxicological and phytochemical complementary studies may be required.

Ecotoxicological risk assessment of contaminants of emerging concern identified by "suspect screening" from urban wastewater treatment plant effluents at a territorial scale

Urban wastewater treatment plants (WWTP) are a major vector of highly ecotoxic contaminants of emerging concern (CECs) for urban and sub-urban streams. Ecotoxicological risk assessments (ERAs) provide essential information to public environmental authorities. Nevertheless, ERAs are mainly performed at very local scale (one or few WWTPs) and on pre-selected list of CECs. To cope with these limits, the present study aims to develop a territorial-scale ERA on CECs previously identified by a "suspect screening" analytical approach (LC-QToF-MS) and quantified in the effluents of 10 WWTPs of a highly urbanized territory during three periods of the year. Among CECs, this work focused on pharmaceutical residue and pesticides. ERA was conducted following two complementary methods: (1) a single substance approach, based on the calculation for each CEC of risk quotients (RQs) by the ratio of Predicted Environmental Concentration (PEC) and Predicted No Effect Concentration (PNEC), and (2) mixture risk assessment ("cocktail effect") based on a concentration addition model (CA), summing individual RQs. Chemical results led to an ERA for 41 CEC (37 pharmaceuticals and 4 pesticides) detected in treated effluents. Single substance ERA identified 19 CECs implicated in at least one significant risk for streams, with significant risks for DEET, diclofenac, lidocaine, atenolol, terbutryn, atorvastatin, methocarbamol, and venlafaxine (RQs reaching 39.84, 62.10, 125.58, 179.11, 348.24, 509.27, 1509.71 and 3097.37, respectively). Mixture ERA allowed the identification of a risk (RQmix > 1) for 9 of the 10 WWTPs studied. It was also remarked that CECs leading individually to a negligible risk could imply a significant risk in a mixture. Finally, the territorial ERA showed a diversity of risk situations, with the highest concerns for 3 WWTPs: the 2 biggest of the territory discharging into a large French river, the Rhône, and for the smallest WWTP that releases into a small intermittent stream.

Accumulation and risk assessment of heavy metals employing species sensitivity distributions in Linggi River, Negeri Sembilan, Malaysia

The constant increase of heavy metals into the aqueous environment has become a contemporary global issue of concern to government authorities and the public. The study assesses the concentration, distribution, and risk assessment of heavy metals in freshwater from the Linggi River, Negeri Sembilan, Malaysia. Species sensitivity distribution (SSD) was utilised to calculate the cumulative probability distribution of toxicity from heavy metals. The aquatic organism's toxicity data obtained from the ECOTOXicology knowledgebase (ECOTOX) was used to estimate the predictive non-effects concentration (PNEC). The decreasing sequence of hazardous concentration (HC₅) was manganese > aluminium > copper > lead > arsenic > cadmium > nickel > zinc > selenium, respectively. The highest heavy metal concentration was iron with a mean value of 45.77 μg L^-1, followed by manganese (14.41 μg L^-1) and aluminium (11.72 μg L^-1). The mean heavy metal pollution index (HPI) value in this study is 11.52, implying low-level heavy metal pollutions in Linggi River. The risk quotient (RQ) approaches were applied to assess the potential risk of heavy metals. The RQ shows a medium risk of aluminium (RQ_m = 0.1125) and zinc (RQ_m = 0.1262); a low risk of arsenic (RQ_m = 0.0122) and manganese (RQ_m = 0.0687); and a negligible risk of cadmium (RQ_m = 0.0085), copper (RQ_m = 0.0054), nickel (RQ_m = 0.0054), lead (RQ_m = 0.0016) and selenium (RQ_m = 0.0012). The output of this study produces comprehensive pollution risk, thus provides insights for the legislators regarding exposure management and mitigation.

Modelling the fate of micropollutants in integrated urban wastewater systems: Extending the applicability to pharmaceuticals

Pharmaceutical active compounds (PhACs) are a category of micropollutants frequently detected across integrated urban wastewater systems. Existing modelling tools supporting the evaluation of micropollutant fate in such complex systems, such as the IUWS_MP model library (which acronym IUWS stands for Integrated Urban Wastewater System), do not consider fate processes and fractions that are typical for PhACs. This limitation was overcome by extending the existing IUWS_MP model library with new fractions (conjugated metabolites, sequestrated fraction) and processes (consumption-excretion, deconjugation). The performance of the extended library was evaluated for five PhACs (carbamazepine, ibuprofen, diclofenac, paracetamol, furosemide) in two different integrated urban wastewater systems where measurements were available. Despite data uncertainty and the simplicity of the modelling approach, chosen to minimize data requirements, model prediction uncertainty overlapped with the measurements ranges across both systems, stressing the robustness of the proposed modelling approach. Possible applications of the extended IUWS_MP model library are presented, illustrating how this tool can support urban water managers in reducing environmental impacts from PhACs discharges.

Characterization of the Nairobi River catchment impact zone and occurrence of pharmaceuticals: Implications for an impact zone inclusive environmental risk assessment

The largely uncontrolled release of active pharmaceuticals ingredients (APIs) within untreated wastewater discharged to waterbodies, associated with many rapidly urbanising centres is of growing concern owing to potential antimicrobial resistance, endocrine disruption and potential toxicity. A sampling campaign has been undertaken to assess the source, occurrence, magnitude and risk associated with APIs and other chemicals within the Nairobi/Athi river basin, in Kenya, East Africa. The catchment showed an extensive downstream impact zone estimated to extend 75 km, mostly, but not exclusively, derived from the direct discharge of untreated wastewater from the urban centre of Nairobi city. The exact extent of the downstream boundary of the Nairobi city impact zone was unclear owing to the inputs of untreated wastewater sources from the continuous urbanized areas along the river, which counteracted the natural attenuation caused by dilution and degradation. The most frequently detected APIs and chemicals were caffeine, carbamazepine, trimethoprim, nicotine, and sulfamethoxazole. Paracetamol, caffeine, sulfamethoxazole, and trimethoprim alone contributed 86% of the total amount of APIs determined along the Nairobi/Athi catchment. In addition to direct discharge of untreated domestic wastewater attributed to the informal settlements within the conurbation, other sources were linked to the industrial area in Nairobi City where drug formulation is known to occur, the Dandora landfill and veterinary medicines from upstream agriculture. It was shown that there was a possible environmental risk of API ecotoxicological effects beyond the end of the traditional impact zone defined by elevated biochemical oxygen demand concentrations; with metronidazole and sulfamethoxazole exhibiting the highest risk.

Life cycle assessment of point source emissions and infrastructure impacts of four types of urban stormwater systems

The implementation, operation and decommissioning of stormwater management systems causes environmental damage, while at the same time reducing pollutant loads in receiving waters by treating stormwater. The focus in research has been either on assessing impacts caused by stormwater infrastructure, or risks associated with stormwater discharges, but rarely have these two sources of environmental impacts been combined to allow a comprehensive environmental evaluation of stormwater management. We assess the environmental sustainability of four different generic stormwater management systems for a catchment of 260ha by a) modelling the flow of pollutants in stormwater, and resulting point source emissions to freshwater, and b) quantifying emissions and resources for all relevant processes associated with the life cycle of the infrastructure. Using life cycle impact assessment, we quantify the resulting environmental impacts and consequent damage to two areas of protection - ecosystems (expressed in time-integrated species loss) and natural resource availability (expressed in extra costs for future resource extraction). Our assessment shows that combined stormwater management causes the highest damage to both ecosystems (1.4E-03 species.yr/yr) and resource availability (8.8E+03 USD/yr). Separate systems using only green infrastructure were found to avoid damage to resource availability (-3.7 to -5.2 USD/yr) and cause lower ecosystem damage (1.1-1.3E-03 species.yr/yr). Stormwater discharges contribute significantly to the total ecosystem damage of the different systems (36-88%), and the sustainability of separate systems can be further improved by optimizing the removal efficiency of low-tech elements like surface basins and filter soil. The systems are designed according to engineering standards. Choosing different criteria, e.g. identical flood safety levels, would result in substantial changes of the relative performance of the systems. The findings highlight the importance of including point source emissions into the assessment to allow comparative conclusions and minimisation of environmental damage of stormwater management.

Pollution levels of stormwater discharges and resulting environmental impacts

Stormwater carries pollutants that potentially cause negative environmental impacts to receiving water bodies, which can be quantified using life cycle impact assessment (LCIA). We compiled a list of 20 metals, almost 300 organic compounds, and nutrients potentially present in stormwater, and measured concentrations reported in literature. We calculated mean pollutant concentrations, which we then translated to generic impacts per litre of stormwater discharged, using existing LCIA characterisation factors. Freshwater and marine ecotoxicity impacts were found to be within the same order of magnitude (0.72, and 0.82 CTUe/l respectively), while eutrophication impacts were 3.2E-07 kgP-eq/l for freshwater and 2.0E-06 kgN-eq/l for marine waters. Stormwater discharges potentially have a strong contribution to ecotoxicity impacts compared to other human activities, such as human water consumption and agriculture. Conversely, contribution to aquatic eutrophication impacts was modest. Metals were identified as the main contributor to ecotoxicity impacts, causing >97% of the total impacts. This is in line with conclusions from a legal screening, where metals showed to be problematic when comparing measured concentrations against existing environmental quality standards.

Identification, assessment and prioritization of ecotoxicological risks on the scale of a territory: Application to WWTP discharges in a geographical area located in northeast Lyon, France

The ecotoxicological risk assessment methodologies developed up to now mainly focus on local pollution and do not incorporate an evaluation and prioritization of the different risk situations present in the same territory. This article presents the different phases of formulating an innovative methodology developed to fill this gap, and its application to all the 18 WasteWater Treatment Plants (WWTP) of a geographical area located northeast of Lyon, France. The aim was also take into account emerging pollutants that are very often "forgotten" in ecotoxicological risk assessments. The results of the study show the extreme diversity of the ecotoxicity of the pollutants present in discharges, with "minimum" PNEC values in the region of a millionth of a microgram (10^-6 μg/l) and "maximum" PNEC values in the region of several tens of micrograms. They also show very considerable diversity of the flows of the receiving watercourses in the territory concerned (from several m³/s to 600 m³/s). The Risk Quotients (RQ) resulting from these 2 datasets, calculated for each WWTP and for each of the 10 pollutants most implicated in ecotoxicological risks (Diclofenac, Amoxicillin, Trimethoprim, Roxithromycin, 17β-estradiol, 17α-Ethynylestradiol, Estrone, Nonylphenol, Octylphenol, Nickel, et NH₄⁺), vary from 0.000002 to 187.7 when using the median concentration values of these pollutants, and from 0.000007 to 3750 when using their maximum concentration values. Globally, they show that: (1) the risks are higher for small streams that receive WWTP discharges of average size, (2) the risks are low to very low for discharges into watercourses with high flow rates.