Freshwater Pollution Research Articles

Assessing Occurrence and Biological Consequences of Contaminants of Emerging Concern on Oceanic Islands

Freshwater streams on oceanic islands serve critical ecological and economic functions. However, these are underrepresented in assessments of pollution from contaminants of emerging concern (CEC). Furthermore, freshwater streams and their endemic fauna often have characteristics that are distinct from those of continental streams and model species, calling extrapolations from studies of such systems into question for island streams. In the current study, we assessed the presence of CEC across three sampling events and five freshwater streams on the Island of Hawai’i. We also exposed juveniles of the native fish species Sicyopterus stimpsoni to a mixture of commonly co-occurring CEC for 96 h in static renewal experiments, testing for impacts of CEC in two ecologically relevant assays of functional performance. CEC from multiple sources were ubiquitous in Hawaiian streams, including human-use pharmaceuticals, agricultural herbicides, and industrial runoff. Concentrations of CEC were comparable to published studies from continental streams, exceeding total concentrations of 1000 ng/L for the eight quantified CEC in four samples, and approaching 2500 ng/L in one sample. Effects on exposed fish were subtle and limited to treatments with higher CEC concentrations but indicated potential impacts of CEC on locomotor performance. These results indicate that Hawaiian streams follow a global trend of widespread freshwater pollution by CEC that are accompanied by subtle effects on native fish species and highlight the need for the inclusion of endemic species and ecologically relevant assays when assessing the effects of contaminants in island habitats.

Anthropogenic Drivers of Variation in Concentrations of Perfluoroalkyl Substances in Otters (Lutra lutra) from England and Wales.

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous environmental contaminants that have been linked to adverse health effects in wildlife and humans. Here, we report the presence of PFASs in Eurasian otters (Lutra lutra) in England and Wales and their association with anthropogenic sources. The following 15 compounds were analyzed: 10 perfluoroalkyl carboxylic acids (PFCAs), 4 perfluoroalkyl sulfonic acids (PFSAs), and perfluorooctane sulfonamide, in livers of 50 otters which died between 2007 and 2009. PFASs were detected in all otters analyzed, with 12/15 compounds detected in ≥80% of otters. Perfluorooctane sulfonate (PFOS) accounted for 75% of the ΣPFAS profile, with a maximum concentration of 6800 μg/kg wet weight (ww). Long-chain (≥C8) PFCAs accounted for 99.9% of the ΣPFCA profile, with perfluorodecanoic acid and perfluorononanoic acid having the highest maxima (369 μg/kg ww and 170 μg/kg ww, respectively). Perfluorooctanoic acid (PFOA) concentrations were negatively associated with the distance from a factory that used PFOA in polytetrafluoroethylene manufacture. Most PFAS concentrations in otters were positively associated with load entering wastewater treatment works (WWTW) and with arable land, suggesting that WWTW effluent and sewage sludge-amended soils are significant pathways of PFASs into freshwaters. Our results reveal the widespread pollution of British freshwaters with PFASs and demonstrate the utility of otters as effective sentinels for spatial variation in PFAS concentrations.

СУЧАСНІ АСПЕКТИ АУДИТУ ЕФЕКТИВНОСТІ ДЕРЖАВНИХ ЗАКУПІВЕЛЬ

The article presents an overview of current aspects of public procurement audit. It is proved that today the scientists have mostly practical recommendations for such an audit and monitoring. It is established that there are no significant, thorough theoretical and methodological developments of scientists on the audit of public procurement in a circular economy, sustainable development. It is proved that special attention at the current stage of formation of the audit of public procurement should be paid to such an area as monitoring their "sustainability". The article identifies economic, environmental and social criteria in the audit of public procurement. Economic factors affect the state of the markets on which trade depends now and in the future. Environmental factors affect the natural systems on which life depends now and in the future. Social factors affect the social systems on which the community depends now and in the future. Among the economic criteria are: fair agreements, innovative research, investment, open competition, open information, use of different suppliers, use of HUB zones, use of local suppliers, conflicts of interest, zoning, dumping, exclusive agreement, seller's conspiracy, buyer's conspiracy, abuse patent, pricing, product typing, refusal of the agreement, corruption (bribery, extortion). Among the ecological criteria are the following: biodiversity conservation, climate adaptation, resource optimization, soil fertility concern, acidification, desertification, eutrophication (waterlogging), fresh water pollution, greenhouse gas emissions, environmental depletion, human health impact, land use change, marine pollution, pollution layer, radiation pollution, depletion of resources, smog, waste. To the social criteria it was included: anti-discrimination, community involvement, equal opportunities, employee involvement, equal pay, fair agreement, freedom of association, grievance and redress processes, human rights, indigenous rights, labour protection and safety, the right to bargain collectively, education and training, workers' rights, child labour, forced labour, trafficking in human beings, choice of suppliers. It is substantiated that among the criteria of sustainability (economic, environmental and social) the red ribbon is the assessment of possible abuses, corruption, bribery, dishonesty of the administration. So, also it has been investigated the relationship between administrative dishonesty and leadership style and reporting distortions.

Accumulation of microplastics in the bivalve mollusc Unio tumidus under experimental and field exposures

Background. An increased production and widespread use of plastics have made microplastic (MP) pollution a serious environmental problem. Most of MP found in the marine environment comes from rivers, however, the freshwater pollution by MP is less studied. Filter-feeding organisms, like bivalve molluscs, are the primary target orga­nisms for MP. Nevertheless, the studies of MP accumulation in the bivalves mainly focus on the marine species and depend on expensive equipment. The goal of this study was to detect the presence of MP in the body of freshwater bivalve mollusc Unio tumidus from a typical field site in Western Ukraine and under laboratory sub-chronic exposure to microplastic at a typical concentration for freshwater. Materials and Methods. For the study, we exposed molluscs to waterborne MP (0.1–0.5 mm) in the concentration of 1.0 mg L-1 corresponding to ~850 items L-1 for 14 days and analysed the concentration of MP in the soft tissues and water every two days. The molluscs and water from the field site, confirmed as polluted one, were also analysed. To estimate the number of MP particles, we used a modified method based on the cleavage of biological materials with potassium hydroxide and hydrogen peroxide and microscopic analysis of MP after the staining with fluorescent Nile Red dye. Results. The MP concentration in the soft tissues of the specimens from the refe­rence site was 9.5 items per soft body and demonstrated a bell-shaped response curve throughout the 14-days exposure with maximum of 327.0 items per body on the 10th day and a negative correlation with the concentration of MP in the experimental tank that changed within the range of 590–790 items L-1. The level of MP in the field specimens from the polluted area was 76.5 items per body, and in the water, it was about 103 items L-1. The maximum MP abundance factor, calculated as CFi = Ci/C0 (utilising the value 9.5 as C0), was 83.18 and 8.05 for 10 days of exposure and field specimens, correspondingly. Conclusion. These data indicate the high accumulative ability of U. tumidus towards microplastics and draw attention to the utilizing of this species for the biomonitoring of microplastics pollution and depuration of surface waters from it.

Effects of Aluminium Contamination on the Nervous System of Freshwater Aquatic Vertebrates: A Review.

Aluminium (Al) is the most common natural metallic element in the Earth’s crust. It is released into the environment through natural processes and human activities and accumulates in aquatic environments. This review compiles scientific data on the neurotoxicity of aluminium contamination on the nervous system of aquatic organisms. More precisely, it helps identify biomarkers of aluminium exposure for aquatic environment biomonitoring in freshwater aquatic vertebrates. Al is neurotoxic and accumulates in the nervous system of aquatic vertebrates, which is why it could be responsible for oxidative stress. In addition, it activates and inhibits antioxidant enzymes and leads to changes in acetylcholinesterase activity, neurotransmitter levels, and in the expression of several neural genes and nerve cell components. It also causes histological changes in nerve tissue, modifications of organism behaviour, and cognitive deficit. However, impacts of aluminium exposure on the early stages of aquatic vertebrate development are poorly described. Lastly, this review also poses the question of how accurate aquatic vertebrates (fishes and amphibians) could be used as model organisms to complement biological data relating to the developmental aspect. This “challenge” is very relevant since freshwater pollution with heavy metals has increased in the last few decades.

It More than Adds Up: Interaction of Antibiotic Mixing and Temperature.

Use of antibiotics for the treatment and prevention of bacterial infections in humans, agri- and aquaculture as well as livestock rearing leads to antibiotic pollution of fresh water and these antibiotics have an impact on free-living bacteria. While we know which antibiotics are most common in natural environments such as rivers and streams, there is considerable uncertainty regarding antibiotics’ interactions with one another and the effect of abiotic factors such as temperature. Here, we used an experimental approach to explore the effects of antibiotic identity, concentration, mixing and water temperature on the growth of Pseudomonas fluorescens, a common, ubiquitous bacterium. We exposed P. fluorescens to the four antibiotics most commonly found in surface waters (ciprofloxacin, ofloxacin, sulfamethoxazole and sulfapyridine) and investigated antibiotic interactions for single and mixed treatments at different, field-realistic temperatures. We observed an overall dependence of antibiotic potency on temperature, as temperature increased efficacy of ciprofloxacin and ofloxacin with their EC50 lowered by >75% with a 10 °C temperature increase. Further, we show that mixtures of ciprofloxacin and ofloxacin, despite both belonging to the fluoroquinolone class, exhibit low-temperature-dependent synergistic effects in inhibiting bacterial growth. These findings highlight the context dependency of antibiotic efficacy. They further suggest antibiotic-specific off-target effects that only affect the bacteria once they enter a certain temperature range. This has important implications as freshwater systems already contain multi-drug antibiotic cocktails and are changing temperature due to environmental warming. These factors will interact and affect aquatic food webs, and hence this creates an urgent need to adapt and improve laboratory testing conditions to closer reflect natural environments.

Micro-plastic pollution in marine, freshwater and soil environment: a research and patent analysis

Micro-plastic pollution in marine, freshwater and soil environment: a research and patent analysis

Environmental concentrations of Roundup in combination with chlorpromazine or heating causes biochemical disturbances in the bivalve mollusc Unio tumidus.

Bivalve molluscs represent the most recognized bioindicators of freshwater pollution. However, their ability to indicate specific xenobiotics in complex exposures is unclear. In this study, we aimed to track the particular effects of the pesticide Roundup (Rnd) and the antipsychotic drug chlorpromazine (Cpz) on the mussel Unio tumidus at the simpler environmentally relevant models. We treated the mussels by Rnd (17 μg L−1), Cpz (18 μg L−1), the mixture of Rnd and Cpz at 18 °C (RndCpz), and Rnd at 25 °C (RndT) and examined their digestive glands after 14 days of exposure. We analyzed total antioxidant capacity, glutathione (GSH&GSSG) and protein carbonyls levels, total and Zn-related concentrations of metallothioneins (MT and Zn-MT, respectively), the activities of CYP450-related EROD, glutathione S-transferase, cholinesterase, caspase-3, citrate synthase (CS), lysosomal membrane integrity (NRR), and Zn level in the tissue. Shared responses were indicated as the increase of the antioxidant, Zn-MT, and EROD levels, whereas the changes of Zn concentration, NRR, and caspase-3 activity were most diverse compared to control. According to discriminant analysis, complex exposures abolished the individual response traits and intensified the harmful effects that caused a decrease in the Zn level in the RndCpz- and RndT-groups and the loss of lysosomal integrity in the RndT-group. We concluded that multi-marker expertise with the application of integrated indices had benefits when evaluating the effects of complex exposures.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-16775-1.

Seasonal monitoring of River through heavy metal bioaccumulation and histopathological alterations in selected fish organs

Heavy metal discharge is the primary cause of freshwater pollution, harming fish health. This research was planned to calculate the seasonal variations in metal (Pb, Cu, and Ni) bioaccumulation in different tissues of Gills, Liver, Kidney, and Muscle from Cirrhinus mrigala sampled from River Chenab from an area of high-intensity pollution near Thatta Muhammad Shah. The results revealed significant (P ≤ 0.5) variations in metals bioaccumulation in different seasons. The lowest level of selected metals was observed in winter, whereas the maximum level was noted in the summer. The concentration of selected heavy metals differed seasonally. During winter Pb concentration distribution in descending order was observed in liver (0.823 ± 0.009 ppm) > kidney(0.817 ± 0.011 ppm) > muscle(0.758 ± 0.009 ppm) > gills(0.742 ± 0.011 ppm). Whereas, in summer it was noted as liver (1.726 ± 0.066 ppm) > gills (1.633 ± 0.060 ppm) > kidney (1.575 ± 0.051 ppm) > muscle (1.532 ± 0.050 ppm). While during winter, the bioaccumulation of Cu in organs was noted with descending order of kidney (1.88 ± 0.038) > liver(1.75 ± 0.037) > gills (1.67 ± 0.043) > muscle (1.45 ± 0.031)ppm, while in summer, it was gills (2.85 ± 0.071) > kidney (2.84 ± 0.082) > liver (2.83 ± 0.068) > muscle (2.72 ± 0.065) ppm. In winter, the Ni bioaccumulation with descending order was in the kidney (7.83 ± 0.139) > liver (7.68 ± 0.159) > muscle (7.63 ± 0.162) > gills (7.61 ± 0.129)ppm and in a season of summer, it was detected as in kidney (8.71 ± 0.129) > muscle (8.59 ± 0.131) > liver (8.56 ± 0.141) > gills (8.56 ± 0.131) ppm. All studied heavy metals were found to be above the WHO permissible limits. Histopathological evaluation of fish tissues has been considered an important indicator of environmental pollution monitoring. Histology of kidney and liver tissues showed congestion, necrosis, dilation in Bowman capsule space, while liver showed necrosis, cytoplasmic vacuolation, and sinusoid dilation. This study revealed that the Chenab River is being polluted due to the untreated discharge of industrial effluents and sewage runoff from the city, and these heavy metals from anthropogenic pollution load have adverse effects on the fish population in the river system.

Nanoplastic pollution inhibits stream leaf decomposition through modulating microbial metabolic activity and fungal community structure

Many studies have proved the impacts of nanoplastic pollution in freshwaters on aquatic organisms and ecosystems. To explore toxic mechanisms of nanoplastics on stream functioning, we conducted a microcosm experiment to investigate the effects of polystyrene nanoparticles (PS NPs, 1–100 μg L−1) on the process of leaf litter decomposition mediated by the microbial community. The chronic exposure to PS NPs at 1 and 100 μg L−1 caused significant decreases in leaf litter decomposition and nutrient (carbon and nitrogen) releases. During the ecological process, some extracellular enzymes (i.e., β-glucosidase, glycine-aminopeptidase, and phenol oxidase) rather than fungal biomass were suppressed. Besides, decreases in the relative abundance of Anguillospora and Setophaeosphaeria weakened their functions in leaf litter decomposition. Thus, the microcosm experiment showed that PS NPs inhibited stream leaf decomposition by modulating the microbial metabolic activity and fungal community structure. Overall, the results of this study provide evidence for the consequences of nanoplastic pollution on freshwater microbial community and stream ecosystem functioning, which is conducive to evaluate the potential risks of nanoplastics in aquatic environments.

The need for a multi-pollutant approach to model the movement of pollutants in surfacewater: A review of status and future challenges

Significant research on surface water pollution modelling has been carried out over diverse landscapes has sought to explain the sources, transport, and surface water pollution. To date, surface water pollution studies have focused on nutrients, plastics, and chemicals. Consequently, the current review aims to identify and synthesise peer-reviewed literature about integrated contaminants modelling in surface water. Thus, highlighting that modelling potentially multiple sources of a pollutant from the surface water has remained a thought-provoking topic. Studies differed significantly in terms of the type of model application and procedures for reporting findings, making it challenging to separate clear trends and patterns. Accordingly, most studies agree that pollutants such as plastics and agrochemicals can have adverse consequences on surface water quality; these coincide with difficulties in modelling pollutant transport. Consequently, no regional or global estimates are available for the water pollution burden of flood-related pollution, considering the demonstrable modelling techniques, the significance of the concurrent impacts of surface water pollution by contaminants. Multi-pollutant approaches to modelling the potential sources of pollution and encourage protective behaviour are essential. Mainstreaming freshwater pollution concerns into planning strategies will also be needed to lessen anthropological contribution to surface water pollution. While the implementation of these models is constrained by lack of adequate field data, the model output must be analysed within the model inputs' uncertainty, data limitations and methodologically established surface water modelling principles from the literature.

Effect of virtual water trade on freshwater pollution in trading partners: a systematic literature review.

Systematic reviews are a more complete, repeatable, and less biased form of literature reviews leading to evidence-based conclusions. A systematic review was conducted on articles that have investigated the trade of virtual gray water (VGW) and its effect on freshwater pollution in importer and exporter partners. Scopus and ScienceDirect databases were searched for journal articles covering VGW trade on global, international, and national scales. The relevant articles then were selected and using snowball approach led to more relevant articles. Then, the required data were extracted and recorded. A total of 34 articles met the inclusion criteria, of which 13 articles studied VGW trade on a national scale, 13 on an international scale, and the rest on a global scale. The present study developed a critical appraisal tool to evaluate the methodological quality of the included articles. The results of the critical appraisal showed that none of the included articles can undergo quantitative synthesis. Research gaps regarding VGW trade were observed in the water-scarce developing countries that need to be covered. One of the policy implications to reduce pollution impacts on water bodies would be agricultural and industrial reforms by VGW exporters. Besides, changes in economic structure in both sides of the trade, and goods or water consumption patterns, especially by VGW importers, can also play an important role in water resource conservation. Therefore, international and multi-stockholder cooperation should be taken to alleviate the environmental impacts of the VGW trade.

The ecopolitics of water pollution and disorderly urbanization in Congo‐Basin plays

AbstractThis essay explores the ecopolitics of water pollution and land (ab)use through disorderly urbanization in two plays from the Congo Basin. I argue that bad governance, in the form of absented‐absence and corruption‐plagued presence, leads to the double violation of human rights and the rights of nature through water pollution and haphazard urbanization. In other words, I use two plays to suggest that political absence and bad governance amount to governmental responsibility for ecological vulnerability manifested through freshwater pollution and unregulated urban expansion. In the first part, I suggest that the government’s failure to provide potable water to its citizens leads to water pollution, violations of the rights of nature and the human right to water and sanitation, as well as disregard for the entangled relations between humans and nature in Ekpe Inyang’s Water Na Life ([2002] 2006). In the second part, I use Henri Djombo’s Le mal de terre (2014) to examine urban sprawl and its effects on the rights of nature as well as land disputes and contested claims to land as consequences of bad governance. Overall, the essay foregrounds freshwater pollution, urban sprawl, and land (ab)uses which are often neglected in ecocritical scholarship from/on Africa.

Editorial and News

Editorial and News

Histopathological alterations in gills, liver, kidney and muscles of Ictalurus punctatus collected from pollutes areas of River.

Untreated sewage and industrial wastes from Faisalabad city are disposed to River Chenab through Chakbandi Main Drain (CMD). The present project is planned to investigate the effects of this freshwater pollution on the body of fish Ictalurus punctatus. The specimens of this fish species were collected upstream and downstream of the entrance of CMD into River Chenab. Fish gills, liver, kidney and muscles from dorsolateral regions of fish were subjected to histopathology. Farmed fish and fish from upstream areas were used as control. Fish collected from polluted experimental sites showed significant damage in selected organs. Gill tissues showed an abnormality in the form of an uplifting of the primary epithelium, fusion, vacuolation, hypertrophy, and necrosis. While liver tissues subjected to hepatocytes degeneration, necrosis, mitochondrial granular hepatocyte, and sinusoids dilation. Kidney tissues indicated increased bowmen space and constricted glomerulus and degenerated nephrons. Edema, necrosis, and atrophy were observed in muscle tissues of fish from polluted areas. Fish from the upstream area showed fused gill lamellae, inflammatory cell infiltration, hypertrophy and vacuolation in hepatocytes. Kidney tissues indicated the presence of nuclear tubular cells, destructive renal tubules, hemorrhage, and necrosis at tubular epithelium. Intra myofibril spaces were also observed in muscles. Specimens of control fish indicated no variation in gills, liver, kidney, and muscles. The present study revealed a strong correlation between the degree of tissue damage and environmental contamination. Present findings also compel global warnings to protect our water bodies and fish to rescue the human population.

Insights into the Time Evolution of Slowly Photodegrading Contaminants.

Photochemical degradation plays an important role in the attenuation of many recalcitrant pollutants in surface freshwaters. Photoinduced transformation kinetics are strongly affected by environmental conditions, where sunlight irradiance plays the main role, followed by water depth and dissolved organic carbon (DOC). Apart from poorly predictable weather-related issues, fair-weather irradiance has a seasonal trend that results in the fastest photodegradation in June and the slowest in December (at least in temperate areas of the northern hemisphere). Pollutants that have first-order photochemical lifetimes longer than a week take more than one month to achieve 95% photodegradation. Consequently, they may experience quite different irradiance conditions as their photodegradation goes on. The relevant time trend can be approximated as a series of first-order kinetic tracts, each lasting for one month. The trend considerably departs from an overall exponential decay, if degradation takes long enough to encompass seasonally varying irradiance conditions. For instance, sunlight irradiance is higher in July than in April, but increasing irradiance after April and decreasing irradiance after July ensure that pollutants emitted in either month undergo degradation with very similar time trends in the first 3–4 months after emission. If photodegradation takes longer, pollutants emitted in July experience a considerable slowdown in photoreaction kinetics as winter is approached. Therefore, if pollutants are photostable enough that their photochemical time trend evolves over different seasons, degradation acquires some peculiar features than cannot be easily predicted from a mere analysis of lifetimes in the framework of simple first-order kinetics. Such features are here highlighted with a modelling approach, taking the case of carbamazepine as the main example. This contaminant is almost totally biorecalcitrant, and it is also quite resistant to photodegradation.

Microplastic pollution in soils and groundwater: Characteristics, analytical methods and impacts

Microplastic (MP) pollution has raised public concerns in recent decades globally due to its wide global spreading and potential toxicity. Most of existing studies have focused on MP pollution in marine, freshwater, and sediment systems. However, much less research attention has been paid to soil, which is a major sink of MPs. Furthermore, research interest in MPs in groundwater is even lower than that in soils. There is a critical need to digest and summarize the existing knowledge and the latest advancements to promote research on MP pollution in soils and groundwater. As the first of its kind, this work provides a systematical review of the newest knowledge on occurrences, sources, analytical methods, and impacts of MPs in both soils and groundwater. It first outlines the characteristics (global occurrences, sources, and pathways) of MP pollution in soils and groundwater. Commonly used analytical methods including sample collection (sites, tools, depth, points, and quantity), sample preparation (drying and sieving), extraction (separation, digestion, etc.), identification (visual sorting, chromatography, and vibration spectroscopy), and quality assurance/quality control are then systematically reviewed. Furthermore, the risks and impacts of MPs on soil properties, plants, animals, and antibiotic resistance genes (ARGs) between microorganisms and humans are discussed. At the end, this review also identifies the knowledge gaps and points out potential directions for future research.

The need for a multi-pollutant approach to model the movement of pollutants in surface-water: A review of status and future challenges

Significant research on surface water pollution modelling has been carried out over diverse landscapes has sought to explain the sources, transport, and surface water pollution. To date, surface water pollution studies have focused on nutrients, plastics, and chemicals. Consequently, the current review aims to identify and synthesise peer-reviewed literature about integrated contaminants modelling in surface water. Thus, highlighting that modelling potentially multiple sources of a pollutant from the surface water has remained a thought-provoking topic. Studies differed significantly in terms of the type of model application and procedures for reporting findings, making it challenging to separate clear trends and patterns. Accordingly, most studies agree that pollutants such as plastics and agrochemicals can have adverse consequences on surface water quality; these coincide with difficulties in modelling pollutant transport. Consequently, no regional or global estimates are available for the water pollution burden of flood-related pollution, considering the demonstrable modelling techniques, the significance of the concurrent impacts of surface water pollution by contaminants. Multi-pollutant approaches to modelling the potential sources of pollution and encourage protective behaviour are essential. Mainstreaming freshwater pollution concerns into planning strategies will also be needed to lessen anthropological contribution to surface water pollution. While the implementation of these models is constrained by lack of adequate field data, the model output must be analysed within the model inputs' uncertainty, data limitations and methodologically established surface water modelling principles from the literature.

Single and binary-combined toxic effects of acetochlor and Cu2+ on goldfish (Carassius auratus) larvae

Acetochlor and copper are common freshwater pollutants and pose a severe threat to aquatic animals. The toxicity of acetochlor (Ac) and Cu2+ toward goldfish larvae was investigated by subjecting the larvae to different concentrations of acetochlor, Cu2+, and mixed solutions for 1, 3, and 7 days. The length of goldfish larvae exposed to the 100 μg/L Ac + 100 μg/L Cu2+ mixed solution was considerably lower than that of the control on day 3, but there were no significant differences among the other groups. The heart rates of the larvae in 100 μg/L Ac + 100 μg/L Cu2+ mixed solution were higher than those of the control group on days 3 and 7. Acetochlor and Cu2+ also caused severe damage to the liver and intestine of the larvae, especially in the 100 μg/L Ac + 100 μg/L Cu2+ mixed solution group. Indicators related to oxidative stress (hydrogen peroxide, catalase, glutathione peroxidase, and total superoxide dismutase) that could potentially be induced by acetochlor or Cu2+ began to increase on day 7, and the enzyme activities of the larvae in the mixed groups were significantly lower than those in the control group. In contrast, the expression levels of the genes related to antioxidant stress were rapidly down-regulated in all groups on the 7th day after exposure. Briefly, the combined toxicity of acetochlor and Cu2+ was stronger than that of the single toxicity treatments. Furthermore, toxicity toward larvae in the mixed solution group (100 μg/L Ac + 100 μg/L Cu2+) was more obvious.

Designing policy mixes for emerging wicked problems. The case of pharmaceutical residues in freshwaters

ABSTRACT Wicked problems continuously emerge in the field of environmental governance. Characterized by goal conflicts, complexity, and uncertainty, wicked problems typically call for participatory policy designs. However, the effects of participation are widely unclear, given the indefinite nature of solutions to wicked problems. This research sheds light on this debate by developing and applying a systematic structural approach to assess policy mixes for emerging wicked problems. Based on a review of literature in the field of public policy and environmental governance, we identify eight assessment criteria matching three dimensions of wicked problems: coherence, consistency, congruence to address conflicts; comprehensiveness and diversity to address complexity; and adaptability, reversibility, and robustness to address informational uncertainty. The concept is demonstrated taking as an example two recently proposed policy mixes to address pharmaceutical freshwater pollution in Germany. This concept demonstration suggests that policy mixes resulting from desk research and participatory processes differ in the way they address wicked problems. These results contribute to systematically assess the role of participation in designing policy mixes for emerging wicked policy problems and open up for more advanced discussions on the role of structural approaches in public policy analyses.