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Iron and steel slags have a long history of both disposal and beneficial use in the coastal zone. Despite the large volumes of slag deposited, comprehensive assessments of potential risks associated with metal(loid) leaching from iron and steel by-products are rare for coastal systems. This study provides a national-scale overview of the 14 known slag deposits in the coastal environment of Great Britain (those within 100 m of the mean high-water mark), comprising geochemical characterisation and leaching test data (using both low and high ionic strength waters) to assess potential leaching risks. The seaward facing length of slag deposits totalled at least 76 km, and are predominantly composed of blast furnace (iron-making) slags from the early to mid-20th Century. Some of these form tidal barriers and formal coastal defence structures, but larger deposits are associated with historical coastal disposal in many former areas of iron and steel production, notably the Cumbrian coast of England. Slag deposits are dominated by melilite phases (e.g. gehlenite), with evidence of secondary mineral formation (e.g. gypsum, calcite) indicative of weathering. Leaching tests typically show lower element (e.g. Ba, V, Cr, Fe) release under seawater leaching scenarios compared to deionised water, largely ascribable to the pH buffering provided by the former. Only Mn and Mo showed elevated leaching concentrations in seawater treatments, though at modest levels (<3 mg/L and 0.01 mg/L, respectively). No significant leaching of potentially ecotoxic elements such as Cr and V (mean leachate concentrations <0.006 mg/L for both) were apparent in seawater, which micro-X-Ray Absorption Near Edge Structure (µXANES) analysis show are both present in slags in low valence (and low toxicity) forms. Although there may be physical hazards posed by extensive erosion of deposits in high-energy coastlines, the data suggest seawater leaching of coastal iron and steel slags in the UK is likely to pose minimal environmental risk.
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Monitoramento Ambiental , Ferro , Aço , Ferro/química , Ferro/análise , Poluentes Químicos da Água/análise , Água do Mar/químicaRESUMO
Biocides are a heterogeneous group of chemical substances intended to control the growth or kill undesired organisms. Due to their extensive use, they enter marine ecosystems via non-point sources and may pose a threat to ecologically important non-target organisms. Consequently, industries and regulatory agencies have recognized the ecotoxicological hazard potential of biocides. However, the prediction of biocide chemical toxicity on marine crustaceans has not been previously evaluated. This study aims to provide in silico models capable of classifying structurally diverse biocidal chemicals into different toxicity categories and predict acute chemical toxicity (LC50) in marine crustaceans using a set of calculated 2D molecular descriptors. The models were built following the guidelines recommended by the OECD (Organization for Economic Cooperation and Development) and validated through stringent processes (internal and external validation). Six machine learning (ML) models were built and compared (linear regression: LR; support vector machine: SVM; random forest: RF; feed-forward backpropagation-based artificial neural network: ANN; decision trees: DT and naïve Bayes: NB) for regression and classification analysis to predict toxicities. All the models displayed encouraging results with high generalisability: the feed-forward-based backpropagation method showed the best results with determination coefficient R2 values of 0.82 and 0.94, respectively, for training set (TS) and validation set (VS). For classification-based modelling, the DT model performed the best with an accuracy (ACC) of 100 % and an area under curve (AUC) value of 1 for both TS and VS. These models showed the potential to replace animal testing for the chemical hazard assessment of untested biocides if they fall within the applicability domain of the proposed models. In general, the models are highly interpretable and robust, with good predictive performance. The models also displayed a trend indicating that toxicity is largely influenced by factors such as lipophilicity, branching, non-polar bonding and saturation of molecules.
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Desinfetantes , Animais , Teorema de Bayes , Desinfetantes/química , Ecossistema , Aprendizado de Máquina , Redes Neurais de ComputaçãoRESUMO
Fundamental to all life, phosphorus is an essential nutrient and, contrastingly, a significant threat to surface water biodiversity globally as one of the most common causes of eutrophication in surface waters worldwide. Freshwater wetland ditches affected by these conditions undergo a conversion from primarily submerged aquatic vegetation to algae or duckweed dominance, leading to anoxic conditions. However, macrophyte biomass harvesting in eutrophic water systems is a promising means of remediation and nutrient recycling. This study seasonally assesses spatial distribution and chemical fractionation of surface water phosphorus, as well as surface biomass abundance and total phosphorus content in the ditch systems at West Sedgemoor (Somerset, UK), a designated site of special scientific interest. Elevated phosphorus concentrations in the surface water were observed across the site, with all sites exceeding e hi the Common Standards Monitoring environmental quality standard value of 0.1 mg L-1 during summer and autumn Sites lacking hydrological flow connectivity with contaminated freshwater inputs, typically had lower surface water phosphorus concentrations than the rest of the moor, with localised hotspots associated with likely cattle related agricultural activity. Summer and autumn were determined as the dominant duckweed growth seasons, in which an estimated 39 kg of phosphorus could be removed via duckweed biomass harvesting, per harvest period.
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Fósforo , Áreas Alagadas , Animais , Bovinos , Fósforo/análise , Hidrologia , Eutrofização , Água , Plantas , Reino Unido , Nitrogênio/análise , Monitoramento AmbientalRESUMO
Chemical contamination from point source discharges in developed (resource-rich) countries has been widely regulated and studied for decades; however, diffuse sources are largely unregulated and widespread. In the European Union (EU), large dischargers report releases of some chemicals, yet little is known of total emissions (point and diffuse) and their relative significance. We estimated copper loadings from all significant sources including industry, sewage treatment plants, surface runoff (from traffic, architecture, and atmospheric deposition), septic tanks, agriculture, mariculture, marine transport (antifoulant leaching), and natural processes. A combination of European datasets, literature, and industry data were used to generate export coefficients. These were then multiplied by activity rates to derive loads. A total of approximately 8 kt of copper per annum (ktpa) is estimated to enter freshwaters in the EU, and another 3.5 ktpa enters transitional and coastal waters. The main inputs to freshwater are natural processes (3.7 ktpa), agriculture (1.8 ktpa), and runoff (1.8 ktpa). Agricultural emissions are dominated by copper-based plant protection products and farmyard manure. Urban runoff is influenced by copper use in architecture and by vehicle brake linings. Antifoulant leaching from boats (3.2 ktpa) dominates saline water loads of copper. It is noteworthy that most of the emissions originate in a limited number of copper uses where environmental exposure and pathways exist, compared with the bulk of copper use within electrical and electronic equipment and infrastructure that has no environmental pathway during its use. A sensitivity analysis indicated significant uncertainty in data from abandoned mines and urban runoff load estimates. This study provided for the first time a methodology and comprehensive metal load apportionment to European aquatic systems, identifying data gaps and uncertainties, which may be refined over time. Source apportionments using this methodology can inform more cost-effective environmental risk assessment and management. Integr Environ Assess Manag 2023;19:1031-1047. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Cobre , Monitoramento Ambiental , Exposição Ambiental , Agricultura , União Europeia , Medição de RiscoRESUMO
Sustainable drainage systems (SuDS) are increasingly deployed to mitigate against increased trace element contaminant loads associated with urban and road runoff. However, there is a lack of research on their capabilities in removing these trace elements, particularly from the dissolved phase. Water samples were taken, following various rainfall events, from three different SuDS in Devon; one wetland pond adjacent to a busy dual carriageway, a new SuDS serving a housing estate and an established SuDS draining a mixed housing/light industrial area. A total of 15 elements were studied over the course of six rain events including the first flush of runoff. Removal rates varied within and between rain events as well as between types of SuDS. Although there was a general (modest) removal of dissolved elements within any given SuDS, this was not the case for all of the elements studied. Highest observed element concentrations entering the SuDS occurred at the onset of a rain event (first flush), the intensity of which, was related to the antecedent dry period. During high flows associated with intense rainfall, the SuDS could also act as a source of trace elements associated with fine particulates (e.g. lead) owing to resuspension of fine particulate material. Mature ponds with an abundance of macrophytes help retain solids and particulate metals, however poor maintenance leading to successional growth of shrubs and trees, reduces the efficiency of metal removal. This study highlighted the importance of long-term management planning to be included within any SuDs scheme.
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Oligoelementos , Poluentes Químicos da Água , Poluentes Químicos da Água/análise , Lagoas , Chuva , Monitoramento Ambiental , Movimentos da ÁguaRESUMO
Phosphorus (P) is a building block for life in which the human body requires 0.55â g of per day. In some cases, this requirement is exceeded by 2â g per day, with P additives contributing to half of this exceedance. The use of P has become prominent as demand for processed convenience foods has increased. P can cause significant eutrophication once discharged to the environment. As of October 2019, 55% of assessed rivers and 73% of assessed lakes in England failed the current water quality standards. A survey was conducted to calculate the average P consumption of individuals who identify as meat eaters, flexitarians, vegetarians and vegans based on stated eating habits and reported P levels in foods, revealing an estimated P consumption of 1715, 1664, 1244, 1125â mg P/day respectively. It was estimated that current diets contribute 45% of the P load to UK wastewater treatment works (WwTW). If the UK population were to all convert to veganism this would decrease by 54% reducing the load to WwTW by over 15,000 tonnes of P per year, or 9000 tonnes of P per year if there was a move towards a 50% vegetarian or vegan population. Finally, the population needs to be better informed on what is in their food and the associated environmental impacts.
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Dieta , Vegetarianos , Humanos , Veganos , Dieta Vegana , CarneRESUMO
The agrochemicals and nutrient losses from farming areas such as paddy farming significantly dictate quality and eutrophication of the freshwater resource. However, how farming and land use pattern affect water qualities and eutrophication remain poorly understood in most African agro-ecosystems. The present study characterized how paddy farming influences water qualities and eutrophication in 10 irrigation schemes in Usangu agro-ecosystem (UA). About 42 water samples were sampled from intakes, channels, paddy fields, and drainages and analyzed for EC, Cl, P, NH4-N, NO3-N, TN, Zn, Cu, Ca, and Mg. We observed water pH ranging from 4.89 to 6.76, which was generally below the acceptable range (6.5-8.4) for irrigation water. NH4-N concentration was in a range of 10.6-70.0 mg/L, NO3-N (8.4-33.9 mg/L), and TN (19.1-21,104 mg/L). NH4-N increased along sampling transect (sampling points) from intakes (5.7-29.1 mg/L), channels (19-20 mg/L), fields (12.9-35.8 mg/L), and outflow (10.6-70.0 mg/L), the same trend were found for NO3-N and TN. The TP determined in water samples were in the range of 0.01 to 1.65 mg/L; where some sites had P > 0.1 mg/L exceeding the allowable P concentration in freshwater resource, thus indicating P enrichment and eutrophication status. The P concentration was observed to increase from intake through paddy fields to drainages, where high P was determined in drainages (0.02-1.65 mg/L) and fields (0.0-0.54 mg/L) compared to channels (0.01-0.13 mg/L) and intakes (0.01-0.04 mg/L). Furthermore, we determined appreciable amount of potentially toxic elements (PTEs) such as Cu, Pb, Cd and Cr in studied water samples. The high N, P, and PTEs in drainages indicate enrichment from agricultural fields leading to water quality degradation and contaminations (eutrophication). The study demonstrates that water quality in UA is degrading potentially due to paddy rice farming and other associated activities in the landscape. Thus, the current study recommends starting initiatives to monitor irrigation water quality in UA for better crop productivity, and improved quality of drainage re-entering downstream through the introduction of mandatory riparian buffer, revising irrigation practices, to include good agronomic practices (GAP) to ensure water quality and sustainability.
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Ecossistema , Qualidade da Água , Agricultura , Eutrofização , Nitrogênio/análise , Fósforo/análise , TanzâniaRESUMO
Soil fertility determines crop growth, productivity and consequently determines land productivity and sustainability. Continuous crop production exploits plant nutrients from soils leading to plant nutrient imbalance, thus affecting soil productivity. This study was conducted to monitor soil fertility status in soils of Usangu agro-ecosystem to establish management strategies. To assess soil fertility status in Usangu agro-ecosystem in Southern Highland Tanzania; 0-30 cm depth soil samples were taken for organic carbon, soil pH, N, P, Ca, K, Mg, S, Al, and micronutrients such as Zn, Mn, Cu, Fe, and Cr analyses by various established standard analytical methods. The results indicated most micronutrients were available in the deficient amount in many studied sites except for Fe and Mn, which were observed to be above optimum requirement. Based on critical levels established in other areas, 90 % of the soils were ranked as N, P, K, and Mg deficient. The micronutrients (Cu, Fe, and Zn) were inadequate in all soils resulting in limited crop growth and productivity. A high concentration of trace metals was detected in agricultural soils, this might affect plant nutrients availability and leading to environmental contamination affecting land productivity and sustainability. The study found that Usangu agro-ecosystem has deprived of soil fertility leading to poor crop growth and productivity. The authors recommend the addition of supplemental materials rich in plant nutrients such as inorganic fertilizer, manure, crop residues, and treated wastes to improve soil fertility for improved productivity and land sustainability.
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Spatial distribution of Potentially Toxic Elements (PTEs) in agricultural soils in Usangu Basin (Mbeya Region)-Tanzania were conducted. The study included three land-use types (paddy farming, maize farming, and conserved community forest areas). About 198 soil samples were collected from November to December 2019 across contrasting land management schemes (Group I dominated by agricultural areas versus Group II dominated by residential and agricultural areas). Total (aqua regia extracts) and bioavailable (Mehlich 3 extracts) PTEs concentrations were analyzed. For Group I and II areas, total and bioavailable concentrations (mg/kg dry weight, mean values) of some PTEs were: chromium 1662 ± 5.2 µg/kg for Group I and 1307 ± 3.9 µg/kg for Group II (Total), 55.1 ± 37.1 µg/kg for Group I and 19.2 ± 21.6 µg/kg for Group II (bioavailable); and lead 5272 ± 1650 µg/kg for Group I and 6656 ± 1994 µg/kg for Group II (Total), 1870 ± 800 µg/kg for Group I and 1730 ± 530 µg/kg for Group II (bioavailable). Soil total PTEs such as cadmium and lead were generally lower in Group I areas than in Group II areas. The reverse scenario was observed for copper. Farming areas had high PTEs concentration than non-farming areas because of anthropogenic activities. Overall, soil total concentrations of Fe (99.5%), As (87%), Se (66%), and Hg (12%) were above Tanzanian Maximum Allowable Limits. This study provides essential baseline information to support environmental risk assessment of PTEs in Tanzanian agro-ecosystem.
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Metais Pesados , Poluentes do Solo , Ecossistema , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , TanzâniaRESUMO
The build-up of heavy metals (HM) in agricultural soils accelerates the HM uptake by plants, which could potentially affect food quality and food safety. Here we studied the status and bioaccumulation of HM from soils to plant parts (roots, stem, and grains) in Usangu agro-ecosystem-Tanzania. In total 68 soil samples and 42 rice plant samples from six irrigation schemes were studied. The concentrations of cadmium-Cd, chromium-Cr, copper-Cu, lead-Pb, zinc-Zn, nickel-Ni, and iron-Fe were determined to estimate accumulation, distribution, bioconcentration. Total soil HM concentration in soil and plant samples was determined by acid digestion. The concentration of HM in soils samples (in mg/kg) were Cr (4.58-42.76), Co (1.486-6.12), Fe (3513.56-12593.99), Zn (7.89-29.17), Cd (0.008-0.073), Cu (0.84-9.25), Ni (0.92-7.98), and Pb (1.82-18.86). The total HM concentration in plant samples were (in mg/kg) were Cu (5.18-33.56), Zn (57.03-120.88), Fe (963.51-27918.95), Mn (613.15-2280.98), Cd (4.3-17.46), Pb (0.01-28.25), Cr (12.88-57.34) and Ni (9.65-103.33). The concentration of HM in soil and plant parts was observed to vary among locations where high concentrations of HM were detected in stems and roots compared to grains. The ratio HM in plants and soil samples (bioconcentration) was higher than one for some sites indicating higher HM uptakes by plants leading to possible health risk to soil invertebrates, animals, and humans. The bioconcentration factor varied among schemes, with the highest values at Igalako and Mahongole, which could be caused by artisanal gold mining and mining quarry existed in the area. Therefore, steps are needed to reverse the situation to balance the HM in agricultural soils and plant tissues to be within acceptable limits.
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The dramatic increase in world population underpins current escalating food demand, which requires increased productivity in the available arable land through agricultural intensification. Agricultural intensification involves increased agrochemicals use to increase land productivity. Increased uses of agrochemicals pose environmental and ecological risks such as contamination and water eutrophication. Consequently, toxic metals accumulate in plant products, thus entering the food chain leading to health concerns. To achieve this study, secondary data from peer-reviewed papers, universities, and government authorities were collected from a public database using Tanzania as a case study. Data from Science Direct, Web of Science, and other internet sources were gathered using specific keywords such as nutrient saturation and losses, water eutrophication, potentially toxic metal (PTEs), and impact of toxic metals on soils, water, and food safety. The reported toxic metal concentrations in agro-ecosystem worldwide are linked to agricultural intensification, mining, and urbanization. Statistical analysis of secondary data collected from East African agro-ecosystem had wide range of toxic metals concentration such as; mercury (0.001-11.0 mg Hg/kg), copper (0.14-312 mg Cu/kg), cadmium (0.02-13.8 mg Cd/kg), zinc (0.27-19.30 mg Zn/kg), lead (0.75-51.7 mg Pb/kg) and chromium (19.14-34.9 mg Cr/kg). In some cases, metal concentrations were above the FAO/WHO maximum permissible limits for soil health. To achieve high agricultural productivity and environmental safety, key research-informed policy needs are proposed: (i) development of regulatory guidelines for agrochemicals uses, (ii) establishment of agro-environmental quality indicators for soils and water assessment to monitor agro-ecosystem quality changes, and (iii) adoption of best farming practices such as split fertilization, cover cropping, reduced tillage, drip irrigation to ensure crop productivity and agro-ecosystem sustainability. Therefore, robust and representative evaluation of current soil contamination status, sources, and processes leading to pollution are paramount. To achieve safe and sustainable food production, management of potential toxic metal in agro-ecosystems is vital.
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Metais Pesados , Poluentes do Solo , China , Ecossistema , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , TanzâniaRESUMO
This study was conducted to assess arsenic (As) status and distribution in Usangu agroecosystem-Tanzania, including three land use. About 198 soil samples were collected in ten irrigation schemes in three land uses. Total and bioavailable As were determined by acid digestion (Aqua regia (AQ)) and Mehlich 3 method (M3) to estimate status, distribution and bioavailability. Arsenic concentration were variable among land use and irrigation schemes where total arsenic ranged 567.74-2909.84 µg/kg and bioavailable As ranged 26.17-712.37 µg/kg. About 12-16% of total arsenic were available for plant uptake. Approximately 86.53% of studied agricultural soils had total As concentration above Tanzania maximum allowable limit. Bioavailable As were lower compared to total As and were within the acceptable threshold. Total arsenic concentration were variable among schemes and higher values were observed in schemes which are highly intensified and mechanized. Thus, this study provides essential site specific preliminary baseline information for As status and distribution in agricultural soils to initiate monitoring and management strategies for increased land productivity and environmental safety.
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Arsênio , Poluentes do Solo , Arsênio/análise , Ecossistema , Monitoramento Ambiental , Poluentes do Solo/análise , TanzâniaRESUMO
Phosphorus (P) is a vital plant macronutrient required for plant growth which usually available in limited amount. P availability for plant uptake in highly weathered soil is controlled by soil erosion and high fixation. The availability of P applied from fertilizers depend on the soil pH, soil sorption capacity (PSC) and P saturation status (PSD), which determines P storage, losses, fixation, and additional P to be added with minimal loss to the environment. PSC and PSD are agro-environmental indicators used to estimate P availability and P loss to the environment. However, PSC and PSD of agricultural soils had been never studied in Tanzanian soils. This study was conducted to assess and estimate P availability, PSC and PSD and the risks of P losses in tropical soils from Usangu basin popular for paddy farming. In total, 198 soil samples from 10 paddy irrigation schemes were collected (November-December 2019) and analyzed for inherent P (PM3), metal oxides of Aluminium (Al M3), iron (Fe M3), and calcium (Ca M3) as main PSC and PSD determinant. The determined concentrations were in range of; P M3 014.9-974.69 mg/kg, Al M3 234.56-3789.36 mg/kg, Fe M3 456.78-2980.23 mg/kg, and Ca M3 234.67-973.34 mg/kg. Estimated PSCM3 ranged 5.62-34.85 mmol/kg with a mean value of 14.14 mmol/kg corresponding to high status, ensuring high P holding capacity for plant uptake. However, some soils had very low PSCM3 creating a risk of P loss to environment. Among soils, the estimated PSD M3 ranged from 0.01 to 17.57% and was below (<24%), indicating low P loss risks to surface and groundwater, however, some soils were observed to have PSDM3 above 15% which correspond to a critical degree of phosphate saturation of 25% in a watershed using oxalate extraction method. Therefore some sites were associated with high P loss to the environment, immediate and precautionary actions for sustainable P management to increase productivity, environmental safety and sustainability are needed to be in place.
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Poluentes do Solo , Solo , Fosfatos , Fósforo , Poluentes do Solo/análise , Tanzânia , Áreas AlagadasRESUMO
While the contamination of agroecosystems with pharmaceutical compounds has been reported, the fate of these compounds, particularly uptake into plants remains unclear. This lack of environmental fate data is evident for a critical class of pharmaceuticals, the antivirals and antiretrovirals (ARVDs). Thus, this study evaluated the root uptake of the antiretroviral compounds nevirapine, lamivudine and efavirenz, and the antiviral compound oseltamivir in lettuce. The lettuce was hydroponically grown in a nutrient solution containing the four ARVD pharmaceutical mixture in the 1-100 µg L-1 concentration range. The measured bioaccumulation showed that efavirenz and lamivudine accumulated to the highest and lowest degree, at concentrations of 3463 ng g-1 and 691 ng g-1 respectively. The translocation factor between the root and leaf for nevirapine was greater than 1. The highest concentration of the pharmaceutical mixture had a physiological impact on the lettuce. Potential toxicity was evidenced by a statistically significant 34% (p = 0.04) mean reduction in root and leaf biomass in the 100 µg L-1 ARVD mix exposed lettuce, compared with the controls. This study advances knowledge of the fate of ARVDs in agroecosystems, in particular, plant root - ARVD interaction and the resulting potentially toxic effects on plants.
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Antivirais , Infecções por HIV , Preparações Farmacêuticas , Humanos , Lactuca , Folhas de Planta , Raízes de PlantasRESUMO
The ability to determine accurately the fate of APIs in soil is essential for rigorous risk assessment associated with wastewater reuse or biosolid recycling to land, particularly in lower income countries where water and fertiliser is scarce. Four APIs (naproxen, ofloxacin, propranolol and nevirapine) with wide ranging functionality were used as examples in the development of the OECD 106 soil partitioning and/or degradation study, with naproxen used to illustrate applying the full methodology. The data showed key methodological criteria require careful consideration and testing to generate accurate and consistent results. Only glass fibre membranes were suitable for all APIs, without unduly adsorbing APIs to their surface, thus effectively restricting the minimum practical pore size to 0.7â µm. Polypropylene plastic centrifuge tubes were shown to be suitable, with careful determination of recoveries. Direct injection liquid chromatography-mass spectrometry could reliably resolve all 4 APIs down to less than µg L-1 in soil solutions, although allowance for matrix effects via standard additions was required in some cases. Greatest analytical challenges were found for the highest molecular weight API with the greatest affinity for sorption to surfaces (ofloxacin). Key variables that can impact on partitioning such as solution pH and dissolved organic carbon concentrations were shown to vary within tests over time and should be accounted for.
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Preparações Farmacêuticas , Poluentes do Solo , Poluentes Químicos da Água , Organização para a Cooperação e Desenvolvimento Econômico , Solo , Poluentes do Solo/análise , Águas Residuárias , Poluentes Químicos da Água/análiseRESUMO
Eutrophication is a significant threat to surface water biodiversity worldwide, with excessive phosphorus concentrations being among the most common causes. Wetland ditches under these conditions shift from primarily submerged aquatic vegetation to algae or duckweed dominance, leading to excessive shading and anoxic conditions. Phosphorus, from both point (e.g. wastewater treatment works) and diffuse (largely agricultural runoff) sources, is currently the central reason for failure in the majority of surface water bodies in England to meet required water quality guidelines. This study assesses phosphorus storage in the ditch systems at West Sedgemoor, a designated site of special scientific interest. Elevated phosphorus concentrations in sediment was observed across the Moor up to 4220 mg Kg-1, almost 10 times that which may be expected from background levels. The highest concentrations were generally observed at the more intensively farmed sites in the north of the moor, near key inlets and the outlet. Based upon their chemical and physical properties, clear distinction was observed between sites outside and within the Royal Society of the Protection of Birds nature reserve, using principal component analysis.
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When assessing the environmental exposure of active pharmaceutical ingredients (APIs), the mass contributed from over the counter (OTC) sales are often not included due to difficulty obtaining this data and topical formats are overlooked completely. This study presents a comprehensive approach, investigating the significance of OTC and topical applications as sources of API releases to wastewater, in addition to temporal and subnational variations in use in the UK. The study provides methods to obtain and make use of OTC sales data which can be applied widely. The calculated releases to wastewater compared well with influent concentrations measured at several UK wastewater treatment plants (WWTPs). Consistent overestimation was observed, attributed to a number of factors, including in-sewer removal. OTC sales were found to make up a large proportion of the mass of ibuprofen (76%) and diclofenac (35%) consumed and topical formats were also found to be vital, contributing disproportionately to wastewater loadings per unit mass of ibuprofen and diclofenac used (43% and 99% of the total mass released, respectively). Releases of the APIs investigated did not vary temporally, but regional variation was significant and where possible should be considered for the most accurate exposure assessment of pharmaceuticals.
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Preparações Farmacêuticas , Poluentes Químicos da Água , Exposição Ambiental , Monitoramento Ambiental , Águas Residuárias/análise , Poluentes Químicos da Água/análiseRESUMO
Sacrificial anodes are attached to the hulls of boats and marine structures to prevent corrosion. Their use inevitably leads to release of zinc as well as impurities in the zinc alloy such as cadmium to the saline environment. Risk assessments and source apportionment exercises require accurate assessments of the potential loads of chemicals into the environment. This research has surveyed a wide variety of zinc anodes for their composition to compare against a reported industry standard as well as using differing methodologies to determine the dissolution rate of zinc and cadmium from anodes. A zinc dissolution rate of 477 g/yr/kg of anode is proposed. Although most anodes tested had concentrations of cadmium within the prescribed limits set by the reported standard, calculated leaching rates from laboratory dissolution experiments suggested as much as 400 g per year of cadmium could leach from zinc anodes used on leisure vessels within UK waters.