Unintentionally-produced persistent organic pollutants in the aquatic environment contaminated from historical chlor-alkali production.

Historical chlor-alkali production has led to substantial concentrations of persistent organic pollutant residues in the environment. This study systematically investigated the distribution of polycyclic aromatic hydrocarbons (PAHs), chlorinated/brominated-PAHs (Cl/Br-PAHs), polychlorinated naphthalenes (PCNs), and hexachlorobutadiene (HCBD) in sediment, lotus (Nelumbo nucifera), and fish samples from Ya-Er Lake, which is a site in China with historical chlor-alkali contamination. The average concentrations [(4.97-1.47) × 103 ng/g dry weight (dw)] of these pollutants in backfill sediments, which were dredged from the lake after chlor-alkali production stopped, were 2.68-70.87 times those in fresh lake sediments (0.622-218 ng/g dw) and reported concentrations in other areas. Correlation analyses indicated that Cl-PAHs, Br-PAHs, and PCNs likely originated from halogenation of parent PAHs in the study area, and the chlorination ratios were larger than those of bromination. The Cl(1/2/3)-PAHs/PAHs and Br(1)-PAHs/PAHs ratios were higher than those for PAHs with more halogen atoms. This contamination extended into the biota, with notable pollutant burdens found in lotus (Nelumbo nucifera, 0.305-77.3 ng/g dw) and even higher concentrations in fish (2.20-345 ng/g lipid weight). Estimated biological soil accumulation factors revealed significant enrichment in lotus organs (mean: 7.19) and fish muscle (mean: 10.65), especially the latter, which highlighted bioaccumulation and potential food chain transfer risks. The estimated daily intakes of PAHs, Cl/Br-PAHs, and HCBD through fish consumption currently pose negligible risks, while dietary intake of PCNs may present health concerns. Continuous monitoring and impact assessments are crucial for developing appropriate risk management strategies to safeguard public health.

Assessment of pesticide residues: a comprehensive analysis of seasonal trends and health implications.

This study assessed the presence of eight pesticide residues in the Indus River, Mianwali, Pakistan, focusing on three sampling sites (S1, S2, and S3) in water, sediment, and the fish species Cyprinus carpio during both dry and wet seasons. Analysis was conducted using gas chromatography with an electron capture detector. Results indicated elevated pesticide concentrations in both seasons, with levels of 0.84 and 0.62 µg/L in water, 12.47 and 9.21 µg/g/dw in sediment, and 17.33 and 12.17 µg/g/ww in fish, with higher concentrations observed during the dry season. Cypermethrin and carbofuran were the primary pesticides detected in water, while endosulfan and cypermethrin were dominant in sediment and fish tissue, often exceeding standard safety thresholds. Principal Component Analysis (PCA) and cluster analysis revealed stronger correlations between sediment and fish muscle, with varying associations among pesticides across seasons. The Hazard Index (HI) surpassed 1 in both seasons, signaling potential health risks to humans. These findings underscore the substantial risk agricultural pesticides pose to the aquatic ecosystem and food chain, highlighting the urgent need for sustainable agricultural practices and stricter regulations to minimize pesticide use and encourage eco-friendly pest management strategies.

Decoding the molecular concerto: Toxicotranscriptomic evaluation of microplastic and nanoplastic impacts on aquatic organisms.

The pervasive and steadily increasing presence of microplastics/nanoplastics (MPs/NPs) in aquatic environments has raised significant concerns regarding their potential adverse effects on aquatic organisms and their integration into trophic dynamics. This emerging issue has garnered the attention of (eco)toxicologists, promoting the utilization of toxicotranscriptomics to unravel the responses of aquatic organisms not only to MPs/NPs but also to a wide spectrum of environmental pollutants. This review aims to systematically explore the broad repertoire of predicted molecular responses by aquatic organisms, providing valuable intuitions into complex interactions between plastic pollutants and aquatic biota. By synthesizing the latest literature, present analysis sheds light on transcriptomic signatures like gene expression, interconnected pathways and overall molecular mechanisms influenced by various plasticizers. Harmful effects of these contaminants on key genes/protein transcripts associated with crucial pathways lead to abnormal immune response, metabolic response, neural response, apoptosis and DNA damage, growth, development, reproductive abnormalities, detoxification, and oxidative stress in aquatic organisms. However, unique challenge lies in enhancing the fingerprint of MPs/NPs, presenting complicated enigma that requires decoding their specific impact at molecular levels. The exploration endeavors, not only to consolidate existing knowledge, but also to identify critical gaps in understanding, push forward the frontiers of knowledge about transcriptomic signatures of plastic contaminants. Moreover, this appraisal emphasizes the imperative to monitor and mitigate the contamination of commercially important aquatic species by MPs/NPs, highlighting the pivotal role that regulatory frameworks must play in protecting all aquatic ecosystems. This commitment aligns with the broader goal of ensuring the sustainability of aquatic resources and the resilience of ecosystems facing the growing threat of plastic pollutants.

Advances of microplastics ingestion on the morphological and behavioral conditions of model zebrafish: A review.

Concerns have been conveyed regarding the availability and hazards of microplastics (MPs) in aquatic biota due to their widespread presence in aquatic habitats. Zebrafish (Danio rerio) are widely used as a model organism to study the adverse impacts of MPs due to their several compelling advantages, such as their small size, ease of breeding, inexpensive maintenance, short life cycle, year-round spawning, high fecundity, fewer legal restrictions, and genetic resemblances to humans. Exposure of organisms to MPs produces physical and chemical toxic effects, including abnormal behavior, oxidative stress, neurotoxicity, genotoxicity, immune toxicity, reproductive imbalance, and histopathological effects. But the severity of the effects is size and concentration-dependent. It has been demonstrated that smaller particles could reach the gut and liver, while larger particles are only confined to the gill, the digestive tract of adult zebrafish. This thorough review encapsulates the current body of literature concerning research on MPs in zebrafish and demonstrates an overview of MPs size and concentration effects on the physiological, morphological, and behavioral characteristics of zebrafish. Finding gaps in the literature paves the way for further investigation.

Assessment, distribution, and ecological risk of contaminants of emerging concern in a surface water-sediment-fish system impacted by wastewater.

The presence of contaminants of emerging concern in aquatic ecosystems represents an ever-increasing environmental problem. Aquatic biota is exposed to these contaminants, which can be absorbed and distributed to their organs. This study focused on the assessment, distribution, and ecological risk of 32 CECs in a Spanish river impacted by effluents from a wastewater treatment plant, analyzing the organs and plasma of common carp. Environmental concentrations in water and sediment were examined at sites upstream and downstream of the wastewater treatment plant. The two downstream sites showed 15 times higher total concentrations (12.4 µg L-1 and 30.1 µg L-1) than the two upstream sites (2.08 µg L-1 and 1.66 µg L-1). Half of the CECs were detected in fish organs, with amantadine having the highest concentrations in the kidney (158 ng g-1 w.w.) and liver (93 ng g-1 w.w.), followed by terbutryn, diazepam, and bisphenol F in the brain (50.2, 3.82 and 1.18 ng g-1 w.w.). The experimental bioaccumulation factors per organ were compared with the bioconcentration factors predicted by a physiologically based pharmacokinetic model, obtaining differences of one to two logarithmic units for most compounds. Risk quotients indicated a low risk for 38 % of the contaminants. However, caffeine and terbutryn showed an elevated risk for fish. The mixed risk quotient revealed a medium risk for most of the samples in the three environmental compartments: surface water, sediment, and fish.

Usefulness of oxidative stress biomarkers in native species for the biomonitoring of pesticide pollution in a shallow lake of the Austral Pampas, Argentina.

Pesticide contamination and its adverse effects on native freshwater species continue to be a worldwide major concern, mainly in developing countries. Passive biomonitoring of pesticide pollution in shallow lakes may be achieved by the simultaneous use of fish and wetland plants. Thus, the present study aimed to evaluate the occurrence of current-use pesticides in the surface water of a shallow lake of the Austral Pampas region (Buenos Aires Province, Argentina) surrounded by intensive agricultural activities and its relationship with a battery of biomarkers, including oxidative stress and genotoxicity, in two native species, the fish Oligosarcus jenynsii and the macrophyte Bidens laevis. A total of 26 pesticide residues were analyzed, and the main ones detected were glyphosate and its metabolite aminomethylphosphonic acid (AMPA), chlorpyrifos, and imidacloprid. In O. jenynsii, hydrogen peroxide (H2O2) content in the liver increased with chlorpyrifos occurrence, while malondialdehyde (MDA) levels in the brain and liver increased with the presence of both chlorpyrifos and glyphosate. In B. laevis, H2O2 and MDA levels in leaves and roots increased with AMPA occurrence. Also, leaf H2O2 contents and root MDA levels increased with chlorpyrifos concentration. In contrast, catalase and peroxidase activities in roots decreased with AMPA and chlorpyrifos occurrence. In both species, mainly H2O2 and MDA levels demonstrated their sensitivity to be used as biomarkers in the biomonitoring of current-use pesticide pollution in shallow lakes. Their use may provide information to plan strategies for environmental conservation by government institutions or decision-makers, and to assess the biota health status.

Probabilistic risk assessment of microplastics on aquatic biota in coastal sediments.

As an emerging form of pollution, microplastic contamination of the coastal ecosystems is one of the world's most pressing environmental concerns. Coastal sediments have been polluted to varying degrees by microplastics, and their ubiquitous presence in sediments poses a threat to marine organisms. However, there is currently no ecological risk assessment of microplastics on aquatic biota in sediments. This study, for the first time, established a new procedure to evaluate the toxicity of microplastics on aquatic biota in sediments, based on the probabilistic risk assessment (PRA) concept. The choice of Zhelin Bay as the case study site was based on its severe pollution status. The average content of microplastics in the sediments of Zhelin Bay was 2054.17 items kg-1 dry weight, and these microplastics consisted of 46 different species. Microplastics in sediments exist in five different forms, with the film form being the main composition, and the majority of microplastics have particle sizes ranging from 100 to 500 µm. Correlation analysis (CA) reveals significant negative correlations between microplastic abundance, and Al2O3 and SiO2. The toxicity of microplastics, based on the PRA concept, suggests that Zhelin Bay surface sediments had a low probability (3.43%) of toxic effects on aquatic biota.

Comparison of methods for the radiological impact assessment of aquatic releases to the waters in the low countries.

Accurate assessment of the radiological impact of liquid discharges on the marine environment is challenging despite all developments in recent years. The lack of consensus on this type of assessment manifests itself even stronger when transborder issues are expected, such as in the Low Countries. Belgium and the Netherlands operate nuclear power plants with discharges in the shared estuary of the Western Scheldt, therefore if there are safety concerns, information on both sides of the border must be coherent. This work provides a comparison of two computational methods used for assessment of aquatic releases in the Western Scheldt estuary and the adjacent North Sea.The work demonstrates a fair degree of consistency in modelling the uptake and fate of key anthropogenic radionuclides. Nevertheless, there are also considerable differences found in sediment and sea species with concentrations ranging by over two orders of magnitude in some cases. These explainable differences are methodological in nature, occurring in codes that underwent extensive validation during development. Therefore, the outcomes of this work clearly demonstrate the need to produce explicit guidance that is specifically tailored to the (inter)national water system of concern. This should not be limited to releases from nuclear power plants, but also include other nuclear applications. For all these reasons, more intensive collaboration and model harmonisation across borders is essential, signalling the direction for future investigations.

Occurrence and tissue distribution of 33 legacy and novel per- and polyfluoroalkyl substances (PFASs) in Baikal seals (Phoca sibirica).

Per- and polyfluoroalkyl substances (PFASs) are bioaccumulative and associated with adverse effects in both wildlife and humans. The occurrence of 33 PFASs was assessed in the plasma, liver, blubber, and brain of 18 Baikal seals (Phoca sibirica) (16 pups and 2 adult females) from Lake Baikal, Russia (in 2011). Of the 33 congeners analysed for: perfluorooctanosulfonic acid (PFOS), 7 long chain perfluoroalkyl carboxylic acids (C8-C14 PFCAs) and 1 branched PFCA (perfluoro-3,7-dimethyloctanoic acid; P37DMOA) were most frequently detected. The PFASs in plasma and liver with the highest median concentrations were legacy congeners: perfluoroundecanoic acid (PFUnA; plasma: 11.2 ng/g w.w.; liver: 7.36 ng/g w.w.), PFOS (plasma: 8.67 ng/g w.w.; liver: 9.86 ng/g w.w.), perfluorodecanoic acid (PFDA; plasma: 5.13 ng/g w.w.; liver: 6.69 ng/g w.w.), perfluorononanoic acid (PFNA; plasma: 4.65 ng/g w.w.; liver: 5.83 ng/g w.w.) and perfluorotridecanoic acid (PFTriDA; plasma: 4.29 ng/g w.w.; liver: 2.55 ng/g w.w.). PFASs were detected in the brain of Baikal seals, indicating that PFASs cross through the blood-brain barrier. In blubber, the majority of PFASs were detected in low abundance and concentrations. In contrast to legacy PFASs, novel congeners (e.g., Gen X) were either detected infrequently or not found in Baikal seals. The worldwide occurrence of PFASs in pinnipeds was compared and lower median concentrations of PFOS were observed in Baikal seals relative to other pinnipeds. Conversely, similar concentrations of long chain PFCAs were found in Baikal seals compared to other pinnipeds. Furthermore, human exposure was assessed by estimating weekly intakes (EWI) of PFASs through Baikal seal consumption. Although PFASs concentrations were comparatively low relative to other pinnipeds, consumption of Baikal seal could exceed current regulatory guidelines.

Probabilistic ecotoxicological risk assessment of heavy metal and rare earth element mixtures in aquatic biota using the DGT technique in coastal sediments.

Heavy metals (HMs) are routine contaminants due to their extensive use worldwide. Rare earth elements (REEs) are emerging contaminants because of their global exploitation for use in the high-tech sector. Diffusive gradients in thin films (DGT) are an effective method for measuring the bioavailable component of pollutants. This study represents the first assessment of the mixture toxicity of HMs and REEs in aquatic biota using the DGT technique in sediments. Xincun Lagoon was chosen as the case study site because it has been contaminated by pollutants. Nonmetric multidimensional scaling (NMS) analysis reveals that a wide variety of pollutants (Cd, Pb, Ni, Cu, InHg, Co, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Yb) are primarily impacted by sediment characteristics. Appraisal of single HM-REE toxicity reveals that the risk quotient (RQ) values for Y, Yb and Ce notably exceeded 1, demonstrating that the adverse effects of these single HMs and REEs should not be ignored. The combined toxicity of HM-REE mixtures in terms of probabilistic ecological risk assessment shows that the Xincun surface sediments had a medium probability (31.29%) of toxic effects on aquatic biota.

Ecotoxicological Properties of Titanium Dioxide Nanomorphologies in Daphnia magna.

In this work, the structural, vibrational, morphological, and colloidal properties of commercial 15.1 nm TiO2 nanoparticles (NPs) and nanowires (NWs, 5.6 thickness, 74.6 nm length) were studied with the purpose of determining their ecotoxicological properties. This was achieved by evaluating acute ecotoxicity experiments carried out in the environmental bioindicator Daphnia magna, where their 24-h lethal concentration (LC50) and morphological changes were evaluated using a TiO2 suspension (pH = 7) with point of zero charge at 6.5 for TiO2 NPs (hydrodynamic diameter of 130 nm) and 5.3 for TiO2 NWs (hydrodynamic diameter of 118 nm). Their LC50 values were 157 and 166 mg L-1 for TiO2 NWs and TiO2 NPs, respectively. The reproduction rate of D. magna after fifteen days of exposure to TiO2 nanomorphologies was delayed (0 pups for TiO2 NWs and 45 neonates for TiO2 NPs) in comparison with the negative control (104 pups). From the morphological experiments, we may conclude that the harmful effects of TiO2 NWs are more severe than those of 100% anatase TiO2 NPs, likely associated with brookite (36.5 wt. %) and protonic trititanate (63.5 wt. %) presented in TiO2 NWs according to Rietveld quantitative phase analysis. Specifically, significant change in the heart morphological parameter was observed. In addition, the structural and morphological properties of TiO2 nanomorphologies were investigated using X-ray diffraction and electron microscopy techniques to confirm the physicochemical properties after the ecotoxicological experiments. The results reveal that no alteration in the chemical structure, size (16.5 nm for TiO2 NPs and 6.6 thickness and 79.2 nm length for NWs), and composition occurred. Hence, both TiO2 samples can be stored and reused for future environmental purposes, e.g., water nanoremediation.

Assessment of wastewater-borne pharmaceuticals in tissues and body fluids from riverine fish.

Riverine fish in densely populated areas is constantly exposed to wastewater-borne contaminants from effluent discharges. These can enter the organism through the skin, gills or by ingestion. Whereas most studies assessing the contaminant burden in exposed fish have focused either on muscle or a limited set of tissues. Here we set out to generate a more comprehensive overview of the distribution of pollutants across tissues by analyzing a panel of matrices including liver, kidney, skin, brain, muscle, heart, plasma and bile. To achieve a broad analyte coverage with a minimal bias towards a specific contaminant class, sample extracts from four fish species were analyzed by High-Performance Liquid Chromatography (HPLC) - high-resolution mass spectrometry (HRMS) for the presence of 600 wastewater-borne pharmaceutically active compounds (PhACs) with known environmental relevance in river water through a suspect-screening analysis. A total of 30 compounds were detected by suspect screening in at least one of the analyzed tissues with a clear prevalence of antidepressants. Of these, 15 were detected at confidence level 2.a (Schymanski scale), and 15 were detected at confidence level 1 following confirmation with authentic standards, which furthermore enabled their quantification. The detected PhACs confirmed with level 1 of confidence included acridone, acetaminophen, caffeine, clarithromycin, codeine, diazepam, diltiazem, fluoxetine, ketoprofen, loratadine, metoprolol, sertraline, sotalol, trimethoprim, and venlafaxine. Among these substances, sertraline stood out as it displayed the highest detection frequency. The values of tissue partition coefficients for sertraline in the liver, kidney, brain and muscle were correlated with its physicochemical properties. Based on inter-matrix comparison of detection frequencies, liver, kidney, skin and heart should be included in the biomonitoring studies of PhACs in riverine fish.

Nonmetric multidimensional scaling and probabilistic ecological risk assessment of trace metals in surface sediments of Daya Bay (China) using diffusive gradients in thin films.

This research is one main objective to assess combined toxicity of trace metal mixtures in aquatic biota in coastal sediments. Coastal sediments around the world are a major reservoir of trace metals from industrial wastewater discharge. Our case study site, Daya Bay in southern China, was selected because it has been under severe man-made impacts. Diffusive gradients in thin films (DGT) technique has proven to be a good method for measuring the bioavailability of trace metals. The bioavailability and distribution of trace metals in surface sediments were investigated along with their possible biological risks. The average bioavailable (DGT-labile) concentrations (µg/L) were 0.44 (V), 0.51 (Cr), 52.49 (Mn), 0.10 (Co), 1.36 (Ni), 0.74 (Cu), 14.53 (Zn), 0.97 (As), 0.14 (Se), 6.73 (Mo), 0.17 (Cd), 0.27 (Sb), 0.10 (W), and 1.32 (Pb). Nonmetric multidimensional scaling (NMS) is a robust multivariate ordination method that makes no assumptions about the distribution of the underlying data. NMS was used to explore that DGT-labile concentrations of trace metals were influenced by sediment properties. NMS results indicated that most DGT- labile trace metals influenced by sediment properties. Risk assessment of single trace metal toxicity revealed that risk quotient (RQ) values for Mn, Cu, Zn and Pb significantly exceeded 1, demonstrating that the toxic effects of these trace metals should be not ignored. The probabilistic ecological risk assessment for integral toxicity of one mixture of 14 trace metals revealed that Daya Bay surface sediments had a low probability (9.04 %) of adverse effects on aquatic biota.

Ecotoxicity of eluates obtained from Basamid® contaminated soils is pH dependent: A study with Hydra viridissima, Xenopus laevis and Danio rerio.

Agrochemicals are mostly used to deplete pests and treat diseases in terrestrial agro-ecosystems. However, their transport through the soil, by leaching and/or runoff, may cause them to reach aquatic systems. Environmental parameters, such as soil pH, can affect this transport, by influencing the magnitude of agrochemicals degradation and chemical reaction. This work aimed at investigating the influence of soil pH on the toxicity of eluates obtained from Basamid® contaminated soils to Hydra viridissima, Xenopus laevis and Danio rerio. For this, a natural soil with pH amended to 5.5, 6.5 and 7.5, was spiked with the recommended dose (RD) of Basamid® (145 mg dazomet/kg soil) and eluates (Ba-E) were prepared with the respective species culture medium. Dilutions of the eluates (0.14-100%), obtained from the three soils (Ba-E 5.5, Ba-E 6.5 and Ba-E 7.5, corresponding to soil spiked with Basamid® RD at soil pH of 5.5, 6.5 and 7.5, respectively), were used to expose the organisms. Results showed that for H. viridissima increased soil alkalinity provoked less mortality comparatively to lower soil pH [LD50,96h of Ba-E 5.5: 10.6% and LD50,96h of Ba-E 7.5: 21.2%]. As for X. laevis and D. rerio Ba-E lethal ecotoxicity was similar across soil pH (LD50,96h varied from 5.7 to 6.9% and from 2.1 to 4.3%, respectively). For malformations, 20% effect dilution (ED) in H. viridissima was significantly higher at Ba-E 7.5 (ED20,96h: 17.4%), comparatively to Ba-E 5.5 and Ba-E 6.5 (ED20,96h: 7.9% and 7.7%, respectively). From the three tested organisms and based on both lethal and sublethal effects, H. viridissima presented the highest tolerance to Basamid® eluates and soil pH was a major factor determining the fumigant toxicity, with higher soil pH levels inducing, lower toxicity. The eluates obtained from soils contaminated with RD of Basamid® induced severe effects to the three aquatic species.

Characterising contaminants distribution in marine-coastal sediments through multivariate and nonparametric statistical analyses: a complementary strategy supporting environmental monitoring and control.

This work investigates a statistical approach analysing data from monitoring activities on marine-coastal areas for environmental quality determination and surveillance. Analyses were performed on a database of the Environmental Protection and Prevention Agency of the Puglia Region. As, Cr, Ni, and Pb concentration values in marine sediments and biota from 2013 to 2015 and 2017 were processed to investigate different contaminant characteristics. Hierarchical cluster analysis identified three contaminant distribution classes with (1) highest Cr, Ni, and Pb concentrations, (2) highest As concentration, and (3) lowest contaminants concentration. The Kruskal-Wallis and Friedman tests showed that contaminant distributions were statistically different when considering the monitoring years and classes. However, statistical similarities resulted during the 2013-2017 and 2014-2015 periods. Spearman's coefficients displayed positive correlations among the pollutants in each matrix and mainly negative correlations for matrices comparison. This methodology aims to provide a practical support for monitoring to identify potential environmental deterioration over time and correlations with specific contamination sources.

Potential health effects of contaminant mixtures from point and nonpoint sources on fish and frogs in the New Jersey Pinelands.

Aquatic ecosystems convey complex contaminant mixtures from anthropogenic pollution on a global scale. Point (e.g., municipal wastewater) and nonpoint sources (e.g., stormwater runoff) are both drivers of contaminant mixtures in aquatic habitats. The objectives of this study were to identify the contaminant mixtures present in surface waters impacted by both point and nonpoint sources, to determine if aquatic biota (amphibian and fish) health effects (testicular oocytes and parasites) occurred at these sites, and to understand if differences in biological and chemical measures existed between point (on-stream) and nonpoint sources (off-stream). To accomplish this, water chemistry, fishes, and frogs were collected from 21 sites in the New Jersey Pinelands, United States. Off-stream sites consisted of 3 reference and 10 degraded wetlands. On-stream sites consisted of two reference lakes and six degraded streams/lakes (four sites above and two sites below wastewater outfalls). Surface water was collected four times at each site and analyzed for 133 organic and inorganic contaminants. One native and five non-native fish species were collected from streams/lakes and native green frogs from wetlands (ponds and stormwater basins). Limited differences in contaminant concentrations were observed in reference and degraded wetlands but for streams/lakes, results indicated that landscape alteration, (upland agricultural and developed land) was the primary driver of contaminant concentrations rather than municipal wastewater. Incidence of estrogenic endocrine disruption (intersex) was species dependent with the highest prevalence observed in largemouth bass and black crappie and the lowest prevalence observed in green frogs and tessellated darters. Parasite prevalence was site and species dependent. Prevalence of eye parasites increased with increasing concentrations of industrial, mycotoxin, and cumulative inorganic contaminants. These findings are critical to support the conservation, protection, and management of a wide range of aquatic species in the Pinelands and elsewhere as habitat loss, alteration, and fragmentation increase with increasing development.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal.

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

The impacts of plastics on aquatic insects.

Environmental contamination by plastics and its negative effect on biodiversity have been well-documented in several types of organisms, especially in marine environments. Therefore, it is necessary to assess the impacts of plastic on other organisms such as aquatic insects, which predominantly inhabit freshwaters. It is widely known that these organisms are sensitive to environmental change, especially by contamination. Therefore, this study aimed at testing the hypothesis that aquatic insects are impacted by plastic contamination. We made a systematic search for international papers related to plastics and aquatic insects in databases such as Google Scholar, Web of Science, and Scopus. We obtained 1217 studies of which 40 discussed the impacts of contamination by plastics on aquatic insects. We identified two main impacts: the first one is caused by the use of black macroplastic to protect crops from contact with the soil in agriculture. These black macroplastics attract tons of adult aquatic insects (terrestrial stage) that mistake the plastic surface for water because they select oviposition sites through phototaxis or polarotaxis. The second one comes from water contamination that can originate from the inadequate disposal of plastics, which harms young aquatic insects (aquatic phase) when they feed, reproduce, and construct shelters. Our results show the negative impacts of plastics on both larvae and adult aquatic insects. Despite the large knowledge gap regarding the impacts of plastic on aquatic insects, the evidence above is sufficient to consider these organisms important in global discussions regarding the impacts of plastic on biodiversity.

Environmentally relevant concentrations of microplastics influence the locomotor activity of aquatic biota.

The occurrence of microplastics (MPs) in various marine and freshwater matrices has attracted great attention. However, the effect of MPs in natural environment on the locomotor performance of aquatic biota is still controversial. Therefore, this meta-analysis was conducted, involving 116 effect sizes from 2347 samples, to quantitatively evaluate the alteration in locomotor behavior of aquatic organisms induced by MPs at environmentally relevant concentrations (≤ 1 mg/L, median = 0.125 mg/L). It was shown that MP exposure significantly inhibited the average speed and moved distance of aquatic organisms by 5% and 8% (p < 0.05), respectively, compared with the control, resulting in an obvious reduction of locomotor ability by 6% (p < 0.05). Egger's test indicated that the results were stable without publication bias (p > 0.05). The complex influence of MPs on the locomotor ability were characterized through random-effects meta-regression analyses, presenting size-, time-, concentration-dependent manners and multi-factors interactions. In addition, several physiological changes, including energy reserve reduction, metabolism disorder, gut microbiota dysbiosis, inflammation response, neurotoxic response, and oxidative stress, of aquatic organisms triggered by MP exposure at environmentally relevant concentrations were also provided, which might account for the MPs-induced locomotor activity decline.

Monensin occurrence in surface water and its impact on aquatic biota in a stream of the southeast Pampas, Argentina.

Monensin is an ionophore antibiotic used as a feed additive and growth promoter in cattle production worldwide. The occurrence of monensin in aquatic surficial ecosystems is of concern due to its possible detrimental effects on human health and native biota. Argentina is one of the most important cattle beef producers worldwide; however, there is little knowledge on the environmental occurrence of monensin and the associated risks to aquatic biota. In this study, we developed a method for the extraction and quantification of monensin in surface water; then, we evaluated the occurrence of monensin in a stream impacted by different animal husbandry's operations, and then, we analyzed the ecological implications of monensin residues on aquatic organisms using the risk quotient (RQ) method. Sampling was carried out on August 2017 from the headwaters to the floodplain of the El Pantanoso stream, Buenos Aires province, Argentina. Monensin detection frequency was 75% (n = 20). The median level was 0.40 µg/L and the maximum concentration was 4.70 µg/L. The main input of monensin was from a cattle slaughterhouse, an activity that has not been considered before in the literature as a source of emission of veterinary pharmaceuticals into the environment. The RQ assessment showed that monensin levels could have potential negative effects on aquatic biota in the sampling site closest to the cattle slaughterhouse. The data obtained in this study shows that monensin was present in El Pantanoso surface waters at levels of high ecotoxicological risk to aquatic biota.