Surface Water Acidification Research Articles

Performance comparison of modified polyethersulfone membrane with graphene oxide and molybdenum disulfide for effective filtration of urban surface water

In the current water treatment scenario, membrane filtration is a crucial technology due to its ability to effectively remove pollutants, ensuring clean and safe water. However, a significant challenge to its widespread application is membrane fouling, which reduces membrane efficiency and service life. Various membrane modifications have been studied to enhance fouling resistance. In this work, the effect of adding graphene oxide (GO) and molybdenum disulfide (MoS2) nanoparticles for the fabrication of mixed polyethersulfone (PES) membranes was evaluated. The modified membranes were evaluated for pollutant removal efficiency and fouling resistance using model humic acid solutions and surface water samples. The PES-GO membranes demonstrated significantly improved hydrophilicity, up to 43% reduction in protein deposition, and an average flux recovery ratio (FRR) of 63%, superior to the control PES membrane, resulting in reduced fouling and sustained high permeability. Nevertheless, although PES-MoS2 exhibited high rejection rates of dissolved organic matter and UV254, they also showed higher foulant adsorption and lower FRR, likely due to the development of a colloidal fouling when treating more complex water matrices. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) analysis confirmed the deposition of organic foulants, with polysaccharides and proteins identified as major contributors to fouling. These findings suggest that while GO-enhanced PES membranes offer improved water treatment performance, modifications with MoS2 require careful consideration of feedwater composition. Future work should focus on optimizing nanoparticle integration and evaluating membrane effectiveness for diverse water sources.

Persulfate activation by biochar and iron: Effect of chloride on formation of reactive species and transformation of N,N-diethyl-m-toluamide (DEET)

Fenton-like processes using persulfate for oxidative water treatment and contaminant removal can be enhanced by the addition of redox-active biochar, which accelerates the reduction of Fe(III) to Fe(II) and increases the yield of reactive species that react with organic contaminants. However, available data on the formation of non-radical or radical species in the biochar/Fe(III)/persulfate system are inconsistent, which limits the evaluation of treatment efficiency and applicability in different water matrices. Based on competition kinetics calculations, we employed different scavengers and probe compounds to systematically evaluate the effect of chloride in presence of organic matter on the formation of major reactive species in the biochar/Fe(III)/persulfate system for the transformation of the model compound N,N‑diethyl-m-toluamide (DEET) at pH 2.5. We show that the transformation of methyl phenyl sulfoxide (PMSO) to methyl phenyl sulfone (PMSO2) cannot serve as a reliable indicator for Fe(IV), as previously suggested, because sulfate radicals also induce PMSO2 formation. Although the formation of Fe(IV) cannot be completely excluded, sulfate radicals were identified as the major reactive species in the biochar/Fe(III)/persulfate system in pure water. In the presence of dissolved organic matter, low chloride concentrations (0.1 mM) shifted the major reactive species likely to hydroxyl radicals. Higher chloride concentrations (1 mM), as present in a mining-impacted acidic surface water, resulted in the formation of another reactive species, possibly Cl2•−, and efficient DEET degradation. To tailor the application of this oxidation process, the water matrix must be considered as a decisive factor for reactive species formation and contaminant removal.

Correlative Effects on Nanoplastic Aggregation in Model Extracellular Biofilm Substances Investigated with Fluorescence Correlation Spectroscopy.

Recent studies show that biofilm substances in contact with nanoplastics play an important role in the aggregation and sedimentation of nanoplastics. Consequences of these processes are changes in biofilm formation and stability and changes in the transport and fate of pollutants in the environment. Having a deeper understanding of the nanoplastics-biofilm interaction would help to evaluate the risks posed by uncontrolled nanoplastic pollution. These interactions are impacted by environmental changes due to climate change, such as, e.g., the acidification of surface waters. We apply fluorescence correlation spectroscopy (FCS) to investigate the pH-dependent aggregation tendency of non-functionalized polystyrene (PS) nanoparticles (NPs) due to intermolecular forces with model extracellular biofilm substances. Our biofilm model consists of bovine serum albumin (BSA), which serves as a representative for globular proteins, and the polysaccharide alginate, which is a main component in many biofilms, in solutions containing Na+ with an ionic strength being realistic for fresh-water conditions. Biomolecule concentrations ranging from 0.5 g/L up to at maximum 21 g/L are considered. We use non-functionalized PS NPs as representative for mostly negatively charged nanoplastics. BSA promotes NP aggregation through adsorption onto the NPs and BSA-mediated bridging. In BSA-alginate mixtures, the alginate hampers this interaction, most likely due to alginate-BSA complex formation. In most BSA-alginate mixtures as in alginate alone, NP aggregation is predominantly driven by weaker, pH-independent depletion forces. The stabilizing effect of alginate is only weakened at high BSA contents, when the electrostatic BSA-BSA attraction is not sufficiently screened by the alginate. This study clearly shows that it is crucial to consider correlative effects between multiple biofilm components to better understand the NP aggregation in the presence of complex biofilm substances. Single-component biofilm model systems based on comparing the total organic carbon (TOC) content of the extracellular biofilm substances, as usually considered, would have led to a misjudgment of the stability towards aggregation.

Current status and risk assessment of perfluoroalkyl acids in surface water and sediments of the Yellow River in Shandong, China

The Yellow River is the main source of water for urban and rural area and agricultural irrigation in northern China. Herein, the distribution and risk assessment of perfluoroalkyl acids (PFAAs) were investigated from the Yellow River in Shandong Province, China. The total concentration of PFAAs (∑PFAAs) in surface water and sediments were 37.5–2128 ng/L (mean: 167 ng/L) and not detected−6.95 ng/g dry weight (dw) (mean: 1.02 ng/g dw), respectively. Short-chain PFAAs-perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), and perfluorobutane sulfonic acid (PFBS) were the most prevalent PFAAs in surface water. Source analysis showed that firefighting foam (proportion: 31.3 %) and textile treatments and food packaging (proportion: 30.3 %) were the main sources of PFAAs in water. Based on the concentration of PFAAs in water, ecological and potential human health risks were assessed. Perfluorooctanoic acid (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA) and perfluoroundecanoic acid (PFUnDA) posed nonnegligible ecological risk for some aquatic organisms. Levels of PFAAs (e.g., PFOA, PFNA, and PFDA etc.) in some water samples were higher than the advisory guidelines of PFAAs concentrations in water worldwide, indicating a potential human health risk. Therefore, PFOA, PFNA, PFDA, and PFUnDA are the key focus of pollutants in the water of the Yellow River in Shandong Province, and the standards and limits of these PFAAs in environments including surface water and sediment should be promoted.

Enhanced mitigation of membrane fouling and degradation of perfluorooctanoic acid in the treatment of natural surface water through the application of dielectric barrier discharge/sulfite

The present study employed a dielectric barrier discharge (DBD)/sulfite system to mitigate membrane fouling and enhance the degradation of perfluorooctanoic acid (PFOA) in surface water. Results showed that the membrane flux was remarkably enhanced by 93.6%, and the degradation of PFOA showed an impressive increase of 87.9%. The synergistic redox effect of free radicals, including hydroxyl radical (•OH), sulfate radical (SO4∙-), electron (e-/eaq-), su-peroxide anion radicals (∙O2-), and other radical, played a crucial role in mitigating membrane fouling, accounting for 36.26%, 30.10%, 18.69%, 6.75%, and 8.20%, respectively. The correlation analysis revealed that effective removal of UV254 and TOC emerged as the most crucial factors positively contributing to mitigating membrane fouling. Additionally, SO4∙-, •OH, and eaq- were identified as the primary active substances responsible for attacking PFOA, accounting for 41.30%, 25.20%, and 23.70%, respectively. The degradation pathway of PFOA was proposed through analysis using density functional theory and mass spectrometry, reducing the biotoxicity of its degradation products. This study presents a suitable strategy for simultaneous mitigation of membrane fouling and enhancement of PFOA degradation, which holds great potential for advancing the field of water treatment towards practical applications.

The deciphering of microplastics-derived fluorescent dissolved organic matter in urban lakes, canals, and rivers using parallel factor analysis modelingand mimic experiment.

The aim of the study is to investigate the leaching of fluorescent dissolved organic matter (fDOM) from microplastics. In addition, this study identifies the connection between fDOM and microplastics in the aquatic environment. Three-dimensional excitation-emission matrix identified five fluorophores, that is, peak A, M, T, Tuv, and Wuv, and the parallel factor analysis modeling identified five components, that is, tryptophan-like, p-hydroxy acetophenone, humic acid (C-like), detergent-like, and fulvic acid (M-like) in the urban surface water. Mimic experiments using commonly used synthetic plastic (like microplastics) in Mili-Q water under solar radiation and dark environments demonstrate the release of fDOM from plastic. Two fluorophore peaks were observed at Ex/Em = 250/302 nm and Ex/Em = 260/333 nm for the expanded polystyrene plastic polymer and one fluorophore peak at Ex/Em = 260/333 nm for the low-density polyethylene. Fluorophore and component intensity exhibited notable associations with microplastics in the aquatic environment. These findings indicated that the characteristics and dynamics of fDOM in urban surface water are influenced by microplastics. PRACTITIONER POINTS: Fluorescent dissolved organic matters were identified in urban surface waters. Expanded polystyrene (EPS) had shown two fluorophores at Em/Ex = 250/302 and Em/Ex = 260/333. Low-density polyethylene (LDPE) had one fluorophore at Em/Ex = 260/333. Fluorophore and component intensity in the aquatic settings exhibited associations with microplastics.

Habitat sensitivity in the West African coastal area: inferences and implications for regional adaptations to climate change and ocean acidification.

This study focuses on assessing coastal vulnerability and habitat sensitivity along the West African coast by delineating hotspots based on surface temperature, pH, chlorophyll-a, particulate organic carbon, and carbonate concentrations between 2018 and 2023 depending on data availability. Initial exploration of these variables revealedtwo distinct focal pointsi.e.,the Togo-Nigerian coastal stretch and the stretch from Sierra Leone to Mauritania.Lower pH trends (acidification) in surface waters were observed off the West African coast, particularly in areas around the south-south Niger Delta in Nigeria and the coastal regions of Guinea and Guinea Bissau. Sea surface temperature analysisrevealed highest temperatures (27-30°C)within Nigeria to Guineacoastal stretch, intermediate temperatures (24-27°C) within the Guinea Bissau and Senegalcoastal stretch, and the lowest temperatures off the coast ofMauritania. Furthermore, correlation analysis between sea surface temperature and calcite concentration in the Mauritania-Senegal hotspot, as well as between overland runoff and particulate organic carbon in the Togo-Nigeria hotspot, revealed strong positive associations (r>0.60) and considerable predictive variability (R2 ≈ 0.40). From the habitat sensitivity analysis, certain regions, including Cape Verde, Côte d'Ivoire, Nigeria, Senegal, and Sierra Leone, exhibited high sensitivity due to environmental challenges and strong human dependence on coastal resources. Conversely, Gambia, Guinea, Guinea-Bissau, Liberia, and Togo displayed lower sensitivity, influenced by geographical-related factors(e.g.coastal layout, topography, etc.) and current levels ofeconomic development(relatively lowerindustrialization levels). Regional pH variations in West African coastal waters have profound implications for ecosystems, fisheries, and communities. Addressing these challenges requires collaborative regional policies to safeguard shared marine resources. These findings underscore the link between ecosystem health, socioeconomics, and the need for integrated coastal management and ongoing research to support effective conservation.

It Is Time to Develop Sustainable Management of Agricultural Sulfur

AbstractGlobally, sulfur (S) applications to croplands result in S inputs that often exceed historical atmospheric deposition. Sulfur is applied to crops as a fertilizer, fungicide, soil conditioner, pH regulator, and carrier for other elements. However, excess S in soils and aquatic ecosystems can have detrimental ecological and biogeochemical consequences, including soil base cation depletion, surface water acidification, hydrogen sulfide toxicity, and increased production of methyl mercury. The dichotomy between S benefits to crops and environmental consequences parallels that of nitrogen and phosphorus; however, there has not yet been a focus on developing sustainable S management plans in agriculture. We review the current literature on S cycling in agricultural systems and propose solutions that reduce S inputs, losses, and ecological consequences, including field applications of organic matter, adaptation of precision agriculture, and implementation of total maximum daily loads. We suggest opportunities for technological innovation, including analysis of remote sensing imagery to identify location and timing of S deficiencies and stresses, crop genetic modification to reduce S requirements, inoculation of plants with arbuscular mycorrhizal fungi to enhance plant S acquisition, and remediation of wetlands and other anoxic environments with high S loads. We conclude with areas for continued research on S biogeochemistry.

Impacts of Long-Term Exposure to Ocean Acidification and Warming on Three-Spined Stickleback (Gasterosteus aculeatus) Growth and Reproduction

The warming and acidification of surface waters as predicted by the IPCC leads aquatic species to face major multifaceted changes in their environment. Although teleosts have efficient regulatory systems to cope with these changes, such changes clearly have the potential to impact their physiological functions. Hence, it is crucial to estimate the ability of teleost fishes to cope with multi-stresses to predict how they will deal with future environments. In this context, we investigated the joint effect of warming and acidification on three-spined stickleback (Gasterosteus aculeatus) from the juvenile stage to adulthood, focusing on parameters linked to growth, sexual maturation, and reproduction. Juvenile sticklebacks were split in 2 climate scenarios: a “Current” scenario corresponding to the current seasonal physico-chemical parameters of the water of the “Rade de Brest” in France, and a “RCP8.5” scenario with a warming of 3 °C and an acidification of 0.4 pH units. After 7 months, fish in the RCP8.5 scenario reached the same size and mass as those in the Current scenario, but they needed greater amounts of food to reach satiety. Furthermore, the mortality rate over the experiment was higher in the RCP8.5 scenario. Muscle lipid content, an indicator of energy reserves, was lower in females in the RCP8.5 scenario, suggesting an increased need for energy to maintain homeostasis and other physiological functions or a divergence in energy allocation strategy. Moreover, females exhibited lower sexual maturation and egg quality under the RCP8.5 scenario, which could have contributed to the lower fertilisation rate observed. Males were more resilient to the RCP8.5 scenario, exhibiting only a trend for lower kidney somatic index scores. Altogether, these results suggest a delay and/or an inhibition of gametogenesis and maturation in fish in warmed and acidified waters. The analysis of blood sex steroid concentrations, brain gene expression profiles, and physiological indexes did not allow us to discriminate between a delay and an inhibition of maturation in the RCP8.5 scenario. Overall, these findings clearly indicate that there is a long-term global impact of combined acidification and warming on the mortality and reproductive performance of three-spined stickleback.

Case Study of Diesters of o-Phthalic Acid in Surface Waters with Background Levels of Pollution.

Lake Baikal was studied as a model for elucidating the general pattern of o-phthalic acid diester (PAE) distributions in surface waters with background pollution levels. The influence of factors including congeners, concentrations, sampling points, seasons, years, and potential sources was considered and the environmental risk for various hydrobionts was established. Priority PAEs in Baikal waters are represented by dimethyl phthalate (DMP), diethyl phthalates (DEP), di-n-butyl phthalate (DnBP) and di-(2-ethylhexyl)phthalate (DEHP). Statistically valuable average concentrations and ranges for DMP, DEP, DnBP, and DEHP were 0.02 (0.01-0.02), 0.07 (0.06-0.09), 0.55 (0.47-0.66), and 0.30 (0.26-0.34) µg/L, respectively. The main factors determining PAE concentrations were the year and season of sampling, whereas sampling points were not among the factors influencing PAE levels. The distribution of PAEs in the water body was characterized by (i) an even distribution of minor hydrophilic DMP and DEP congeners in the whole water body, (ii) a maximum concentration of hydrophobic DnBP and DEHP congeners in the upper and near-bottom layers of the water column, and (iii) a low concentration of hydrophobic congeners in the near-shore area. The main PAE source was found to be the atmospheric transfer of polluted air masses, while the supply of PAEs from coastal sources to the pelagic zone was low. The contribution of biogenic sources to the background level of PAEs in the surface waters of Lake Baikal was established. The ecological risk of the background concentration level of PAEs for Lake Baikal biota was estimated. It was found that (i) DMP and DEP congeners do not represent a risk, or represent a very low risk, (ii) the concentration levels of dominant DnBP and DEHP congeners represent a low risk for crustaceans and fishes but (iii) a rather high risk for algae at a DEHP concentration of 0.30 µg/L.

Anthropogenic acidification of surface waters drives decreased biogenic calcification in the Mediterranean Sea

Anthropogenic carbon dioxide emissions directly or indirectly drive ocean acidification, warming and enhanced stratification. The combined effects of these processes on marine planktic calcifiers at decadal to centennial timescales are poorly understood. Here, we analyze size normalized planktic foraminiferal shell weight, shell geochemistry, and supporting proxies from 3 sediment cores in the Mediterranean Sea spanning several centuries. Our results allow us to investigate the response of surface-dwelling planktic foraminifera to increases in atmospheric carbon dioxide. We find that increased anthropogenic carbon dioxide levels led to basin wide reductions in size normalized weights by modulating foraminiferal calcification. Carbon (δ13C) and boron (δ11B) isotopic compositions also indicate the increasing influence of fossil fuel derived carbon dioxide and decreasing pH, respectively. Alkenone concentrations and test accumulation rates indicate that warming and changes in biological productivity are insufficient to offset acidification effects. We suggest that further increases in atmospheric carbon dioxide will drive ongoing reductions in marine biogenic calcification in the Mediterranean Sea.

Spatiotemporal variability of dissolved inorganic macronutrients along the northern Antarctic Peninsula (1996–2019)

AbstractThe northern Antarctic Peninsula is a key region of the Southern Ocean due to its complex ocean dynamics, distinct water mass sources, and the climate‐driven changes taking place in the region. Despite the importance of macronutrients in supporting strong biological carbon uptake and storage, little is known about their spatiotemporal variability along the northern Antarctic Peninsula. Hence, we explored for the first time a 24‐year time series (1996–2019) in this region to understand the processes involved in the spatial and interannual variability of macronutrients. We found high macronutrient concentrations, even in surface waters and during strong phytoplankton blooms. Minimum concentrations of dissolved inorganic nitrogen (DIN; 16 μmol kg−1), phosphate (0.7 μmol kg−1), and silicic acid (40 μmol kg−1) in surface waters are higher than those recorded in surrounding regions. The main source of macronutrients is the intrusions of Circumpolar Deep Water and its modified variety, while local sources (organic matter remineralization, water mass mixing, and mesoscale structures) can enhance their spatiotemporal variability. However, we identified a depletion in silicic acid due to the influence of Dense Shelf Water from the Weddell Sea. Macronutrient concentrations show substantial interannual variability driven by the balance between the intrusions of modified Circumpolar Deep Water and advection of Dense Shelf Water, which is largely modulated by the Southern Annular Mode (SAM) and to some extent by El Niño‐Southern Oscillation (ENSO). These findings are critical to improving our understanding of the natural variability of this Southern Ocean ecosystem and how it is responding to climate changes.

Response of Forest Ecosystems to Decreasing Atmospheric Nitrogen Deposition

Nitrogen deposition has serious consequences to global change. Excessive nitrogen deposition leads to nitrogen saturation in forests, resulting in soil acidification, nitrate leaching, an increase in nitrous oxide emissions, and a decrease in plant species diversity and vegetation productivity. Under the reduction of atmospheric nitrogen deposition in Europe, North America, and China, summarizing the response of forests to decreasing nitrogen deposition can not only improve the knowledge framework of the impact of nitrogen deposition on forests, but also evaluate the effects of emission abatement actions, as well as provide scientific basis for future air pollution control. This study reviewed the response of soil, surface water, nitrogen cycle, and vegetation of temperate forests in Europe and North America and subtropical forests in southwest China to the reduction in atmospheric nitrogen pollution gases and thus nitrogen deposition. The soil water nitrogen concentration responded rapidly to the nitrogen deposition reduction, although the trend was inconsistent. The soil acidification and nitrogen cycles showed a delayed response of recovery from high nitrogen deposition. The nitrogen mineralization and immobilization, soil carbon retention, and net primary production might take decades to respond to the nitrogen deposition reduction. However, the soil inorganic nitrogen pool and nitrogen leaching decreased with the decline in nitrogen deposition, although a one-or two-year lag existed. The surface water nitrogen concentration was closely related to nitrogen status in forests. After the nitrogen deposition decreased, the nitrogen leaching and thus the surface water nitrogen concentration decreased in the areas with historically high nitrogen deposition. However, the low surface water nitrogen concentration in the nitrogen-limited forests was not significantly affected by the nitrogen deposition changes. The recovery of surface water acidification was affected by soil sulfur desorption/mineralization and nitrification/denitrification. The foliar nitrogen concentration decreased with the decline in nitrogen deposition. The nitrogen-saturated forests and regional surface water in southwest China showed a recovery trend from high nitrogen deposition, as a consequence of the implementation of the Total Emissions Control of Air Pollutants and later the Action Plan of Air Pollution Prevention and Control.

Assessing impacts of sulfur deposition on aquatic ecosystems: A decision support system for the Southern Appalachians

AbstractWith climate change and ongoing impacts from human development and resource extraction, US federal land management agencies are acutely concerned with managing for healthy aquatic ecosystems in the Southern Appalachian Mountain (SAM) Region. Here, we describe development of a spatial decision support application to assess the biological and ecological impacts of atmospheric S and N deposition on aquatic ecosystems of the region. We first summarize foundational published work to predict continuous maps of surface water acid neutralizing capacity (ANC) and soil base cation weathering (BCw). We use the predicted ANC and BCw maps to estimate steady‐state critical loads (CLs) of atmospheric S and N deposition. We included estimated CLs of atmospheric N to get a complete picture of CLs and potential exceedances. We then present a logic‐based decision support model for assessing effects of S and N deposition based on statistically modeled stream ANC and CL exceedance. The model is easily modified for continuous monitoring of CL exceedance patterns as new S and N deposition and ANC data become available. We present mapped model results for the SAM study area and an important subset of the region, the Great Smoky Mountains National Park. ANC modeling results revealed that predicted acid sensitivity was spatially variable, with areas of relatively low stream ANC (<50 μeq · L−1) and soil BCw (<50 meq · m−2 · year−1) predominantly found in certain critical areas. Within the Great Smoky Mountains National Park, evidence for S CL exceedance based on an ANC criterion of 50 μeq · L−1 was strong at locations where ambient S deposition was at least two times the CL. We also predicted likely impacts of CL exceedances on aquatic insect species richness and native fish abundance. Responses for insect species richness and fish impact showed variability similar to CL exceedance, with increasing impact positively correlated with elevation. Finally, we discuss ways that the decision support system can be used to prioritize management across the region.

Ammonoid extinction versus nautiloid survival: Is metabolism responsible?

Abstract Understanding the mechanism of selective extinction is important in predicting the impact of anthropogenic environmental changes on current ecosystems. The selective extinction of externally shelled cephalopods at the Cretaceous-Paleogene (K-Pg) mass extinction event (ammonoids versus nautiloids) is often studied, but its mechanism is still debated. We investigate the differences in metabolic rate between these two groups to further explore the causes of selective extinction. We use a novel metabolic proxy—the fraction of metabolic carbon in the stable carbon isotope ratio of shell material (Cmeta)—to determine metabolic rate. Using this approach, we document significant differences in Cmeta among modern cephalopod taxa (Nautilus spp., Argonauta argo, Dosidicus gigas, Sepia officinalis, and Spirula spirula). Our results are consistent with estimates based on oxygen consumption, suggesting that this proxy is a reliable indicator of metabolic rate. We then use this approach to determine the metabolic rates of ammonoids and nautiloids that lived at the end of the Cretaceous (Maastrichtian). Our results show that the nautiloid Eutrephoceras, which survived the K-Pg mass extinction event, possessed a lower metabolic rate than co-occurring ammonoids (Baculites, Eubaculites, Discoscaphites, and Hoploscaphites). We conclude that the lower metabolic rate in nautiloids was an advantage during a time of environmental deterioration (surface-water acidification and resulting decrease in plankton) following the Chicxulub asteroid impact.

Assessment of Manure Compost Used as Soil Amendment—A Review

Organic waste management is an important concern for both industries and communities. Proper management is crucial for various reasons, such as reducing greenhouse gas emissions, promoting sustainability, and improving public health. Composted manure is a valuable source of nutrients and organic matter that can be used as a soil amendment in agriculture. Some important benefits of using composted manure in agriculture include: improves soil fertility, enhances soil structure, reduces soil erosion, suppresses plant diseases, and reduces reliance on synthetic fertilizers. Composted manure represents one of the most effective methods of organic waste valorization. Its macronutrients and micronutrients content can increase plant yield, without any reported negative or toxic effects on the soil and plants at various application rates. However, improper use of farmyard manure can have negative effects on the environment, such as air pollution from greenhouse gas emissions, soil acidification, and contamination of surface water and groundwater by nitrates and phosphates. The properties of the soil, including aeration, density, porosity, pH, water retention capacity, etc., can be improved by the structure and composition of manure. The slow-release source of nutrients provided by the nutrient content of compost can determine proper plants growth. However, it is crucial to use compost in moderation and regularly test soil to prevent excessive nutrient application, which can have adverse effects on plants and the environment.

Crystal chemistry of globular layered silicates of the Troitsko-Bainovskoye fre-clay deposit (Middle Urals)

Research subject. The composition and crystal chemistry of glauconite from the open deposits (K2cn-cp) of the Poldnevskaya area of the Troitsko-Bainovskoye deposit of fire clays.Materials and methods. An analysis of the mineralogical and crystallochemical properties of glauconite was carried out using a set of modern analytical methods (“Geonauka” Centre for Collective Use, IG FRC Komi SC UB RAS): X-ray diffractometry, IR-spectroscopy, scanning electron microscopy, modeling of diffraction profiles.Results and conclusions. The crystal-chemical features of glauconite were determined. Two main glauconite varieties (green and light green) in the rocks of the Zaikovskaya suite were distinguished and their differences and degree of maturity have been established. It was found that dark green globules are close to glauconite and represent a more “mature” variety, while the light green ones are a disordered mixed-layer mineral of the mica (glauconite) – smectite series and are a product of incomplete replacement of the original smectite by glauconite. Phase heterogeneity of glauconite globules was revealed. It has been established that the rocks of the Troitsko-Bainovskoe deposit are exposed to intensive transformation under the influence of acidic surface and technogenic waters, which result in the destruction of the initial minerals and the appearance of secondary mineralization. Clay minerals of the glauconite-bearing rocks are represented by disordered mixed-layer phases of predominantly illite/smectite type.

Leaching characteristics and solidification strategy of heavy metals in solid waste from natural graphite purification.

The tailings and fluorine-containing sludge were produced during the physical and chemical purification of natural crystalline graphite, containing heavy metals in different occurrence forms. To evaluate the threat of different heavy metals to the environment, this work uses the modified sequential extraction method (BCR) to study the presence of heavy metals in two solid wastes and their dissolution characteristics in different environments. The results show that the pollution risk of heavy metals in graphite tailings to the environment is ranked as Mn > Cr > Ni > Zn, and the pollution risk of Mn in fluorine-containing sludge is higher than that of Cr. This is because the Mn in the two solid wastes mainly exists in the form of weak acid extraction. The leaching number of heavy metals in the two solid wastes is directly proportional to the soaking time and soaking temperature, and inversely proportional to the pH value and the solid-to-liquid ratio. The number of heavy metals dissolved in solid waste landfills is significantly higher than that of acid rain and surface water environments. Based on the above results and the distribution of graphite solid waste, solidification agent was suggested to prevent heavy metal dissolution and reduce environmental risks.

Biogeochemical shifts and zooplankton responses in post-CAAA northeastern lakes: The success of acid recovery, complexity of biological recovery, and value of long-term monitoring

Lakes in the northeastern U.S., as in other regions, experienced significant declines in water quality and ecosystem health in the mid to late 20th century as atmospheric deposition from industrial emissions caused surface waters to acidify. After the Clean Air Act Amendments of 1990 enhanced regulations to limit emissions of sulfur and nitrogen, many lakes in the Northeast recovered from acidification. The organisms that inhabit lakes are susceptible to these shifts, and zooplankton can serve as valuable indicators of lake ecosystem responses to shifts due to their position as primary consumers in the food web. We evaluated a large historical dataset from the U.S. Environmental Protection Agency (EPA) Eastern Lake Survey (ELS) of 143 lakes throughout the northeastern U.S. to understand how recovery from acidification and subsequent chemical changes influenced zooplankton body size and community composition. We observed significant changes in chemistry; surface water sulfate concentrations decreased by 22% in the ELS lakes between the two sample years of 1986 and 2004. Increasing concentrations of DOC are common from the combined influence of deacidification and climate change, and the ELS lakes experienced a 26% increase in DOC. Notably, in the more developed regions of our study area, chloride concentration in lakes tripled, likely due to increased use of road deicers, and this is related to a subsequent increase in calcium and magnesium base cations. Zooplankton body size increased significantly between 1986 and 2004 across all taxa, and body size of Daphnia species, which require higher amounts of calcium than other zooplankton taxa, was positively associated with high calcium lakes. Shifts in zooplankton community structure, however, were most strongly influenced by variation in ANC, sulfate, and DOC. Our findings indicate that, while surface water acidity has a strong influence on zooplankton community structure, zooplankton populations are likely on a different trajectory than a simple recovery due to multiple chemical changes, such as increased chloride, occurring in lakes undergoing acid recovery. These, along with changes in climate and land-use, elicit multiple simultaneous responses in zooplankton communities.

The first fully optimized and validated SPE-LC-MS/MS method for determination of the new-generation neonicotinoids in surface water samples

Widespread use of the new generation neonicotinoids (NQs) results in their constant inflow to water bodies. Both their persistence in waters and mechanism of action similar to older compounds already banned in the EU raise concerns about potential ecotoxicological effects. Information about presence of the new NQs in the aquatic environment is still sparse, and the consequences for aquatic organisms remain mostly unknown, due to the lack of sensitive and selective analytical tools. Therefore, a method utilizing solid-phase extraction and liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) has been developed and optimized, enabling the monitoring of EU-approved NQs: acetamiprid (ACT), sulfoxaflor (SFX) and flupyradifurone (FLU), and common NQ metabolite 6-chloronicotinoic acid (6-CNA) in surface waters. To optimize their extraction from natural water samples, the response surface methodology (RSM) was used. An increase in pH value favored higher absolute recoveries (AR) of ACT, SFX and FLU, while the opposite effect was observed for 6-CNA. Increasing water sample volume had adverse effect on the extraction of all compounds. The optimal conditions for simultaneous extraction of all compounds included the use of Oasis HLB sorbent, 200 mL of a water sample at pH of 4.6, and application of 0.3% HCOOH in acetonitrile as an eluent, allowing to obtain AR values above 80% in most cases. Further increase in pH value had positive impact on extraction effectiveness of ACT, SFX and FLU. The method was subjected to full matrix-matched validation and was proven to be fully reliable for the analysis of ACT, SFX and FLU, while the successful isolation of 6-CNA depends on the matrix composition. Finally, the method was applied to the analysis of NQs in surface water samples, proving its sensitivity and selectivity. It can be easily adapted as a tool for trace analysis of NQs and for NQ-associated risk assessment in aquatic ecosystems.