Assessment Of Environmental Pollution Research Articles

Assessment of heavy metal pollution of plants grown adjacent to power generators in Ramadi city

Tree leaves are a useful tool for environmental quality monitoring and heavy metal soil pollution assessment. This study aimed to assess the possibility of heavy metals’ accumulation in the leaves of urban plants as a biological indicator of soil pollution. The plant leaf and soil samples were collected from 51 sites adjacent to power generators in Ramadi-Iraq. Six common plant species, namely, Albizia lebbeck, Conocarpus lancifolius, Dodonaea viscosa, Eucalyptus camaldulensis, Ficus microcarpa, and Ziziphus spina-christi were selected. The highest heavy metal content was found in Conocarpus viscosa leaves followed by Dodonaea viscosa . These two plants have a significant difference (p<0.05) in the heavy metal content compared to other plants. The total average of plant heavy metal concentration was as follows: Mn (45.23), Cu (12.49), Ni (7.55), Pb (6.49), Cr (6.37), Co (2.04), Cd (0.57) mg per kg. Concentrations of heavy metals in leaves have the trend as Mn> Cu> Ni> Pb> Cr> Co> Cd, whereas, the heavy metal bioaccumulation factor (ACF) in plants follows by the order: Zn> Cu> Cd> Mn> Co> Pb> Ni> Cr. A high concentration of cobalt, cadmium, chromium, nickel, and lead are found in the plant leaves compared to the Food and Agriculture Organization / World Health Organization (FAO/WHO) permissible values. This supports the claim that the leaves of the plant can be used as a good indicator of heavy metal accumulation.

Environmental Impact Assessment Related by Energy Sector in Rovinari Mining Area

Abstract In this article an impact assessment is carried out, generated by activities in the energy sector related to Rovinari mining area. Energy-related activities in this area are carried out by open pit mining activities in the context of Tismana, Roșia, Pinoasa, Peşteana and Rovinari locations and Rovinari thermal power plant. Some information that has formed the input for the author’s approach has been provided by SC. Complexul Energetic Oltenia SA (CEO) and S.C. Institute of Scientific Research, Technological Engineering and Mine Designs on Lignite S.A. Craiova (ICSITPML) which has been processed, analysed and used for the presented environmental impact assessment. Two methods from specialized studies have been used for the impact assessment, namely: the Matrix Method for Rapid Impact Assessment (MERI) and the Method for Integrated Quantitative Impact and Risk Assessment of Environmental Pollution (EIRM). Based on the analysis carried out, it can be concluded that the activity in this sector does not lead to significant negative effects strictly associated with it.

Zebrafish, an In Vivo Platform to Screen Drugs and Proteins for Biomedical Use.

The nearly simultaneous convergence of human genetics and advanced molecular technologies has led to an improved understanding of human diseases. At the same time, the demand for drug screening and gene function identification has also increased, albeit time- and labor-intensive. However, bridging the gap between in vitro evidence from cell lines and in vivo evidence, the lower vertebrate zebrafish possesses many advantages over higher vertebrates, such as low maintenance, high fecundity, light-induced spawning, transparent embryos, short generation interval, rapid embryonic development, fully sequenced genome, and some phenotypes similar to human diseases. Such merits have popularized the zebrafish as a model system for biomedical and pharmaceutical studies, including drug screening. Here, we reviewed the various ways in which zebrafish serve as an in vivo platform to perform drug and protein screening in the fields of rare human diseases, social behavior and cancer studies. Since zebrafish mutations faithfully phenocopy many human disorders, many compounds identified from zebrafish screening systems have advanced to early clinical trials, such as those for Adenoid cystic carcinoma, Dravet syndrome and Diamond–Blackfan anemia. We also reviewed and described how zebrafish are used to carry out environmental pollutant detection and assessment of nanoparticle biosafety and QT prolongation.

Identification and removal of micro- and nano-plastics: Efficient and cost-effective methods.

Microplastics (MPs) and nanoplastics (NPs) have gained much attention in recent years because of their ubiquitous presence, which is the widely acknowledged threat to the environment. MPs can be <5 mm size, while NPs are <100 nm, and both can be detected in various forms and shapes in the environment to alleviate their harmful effects on aquatic species, soil organisms, birds, and humans. In efforts to address these issues, the present review discusses about sampling methods for water, sediments, and biota along with their merits and demerits. Various identification techniques such as FTIR, Raman, ToF-SIMS, MALDI TOF MS, and ICP-MS are critically discussed. The detrimental effects caused by MPs and NPs are discussed critically along with the efficient and cost-effective treatment processes including membrane technologies in order to remove plastics particles from various sources to mitigate their environmental pollution and risk assessment.

Recent Trends in Development of Nanomaterials Based Green Analytical Methods for Environmental Remediation

Background: In recent years, the occurrence and fate of environmental pollutants has been recognized as one of the emerging issues in environmental chemistry. A survey documented a wide variety of these pollutants, which are often detected in our environment and these are a major cause of shortened life spans and global warming. These pollutants include toxic metal, pesticides, fertilizers, drugs, and dyes released into the soil and major water bodies. The presence of these contaminants causes major disturbance in the balance of the eco-system. To tackle these issues, many technological improvements are made to detect minute contaminations. The latest issue being answered by scientists is the use of green nanomaterials as sensors which are economical, instant and give much better results at low concentrations and can be used for the field measurements resulting in no dangerous by-product that could lead to more environmental contamination. Nanomaterials are known for their wide bandgap, enhanced physical, and optical properties with the option of tuneability as per need, by optimizing certain parameters. They are proved to be a good choice for analytical/ optical sensors with high sensitivity. Objective: This review holds information about multiple methods that use green nanomaterials for the analytical assessment of environmental pollutants. UV-Vis spectrophotometry and electrochemical analysis using green and reproducible nanomaterials are the major focus of this review article. To date, there are a number of spectrophotometric and electrochemical methods available that have been used for the detection of environmental pollutants such as toxic metals, pesticides, and dyes. Conclusion: The use of nanomaterials can drastically change the detection limits due to having a large surface area, strong catalytic properties, and tunable possibility. With the use of nanomaterials, lower than the marked limit of detection and limit of quantification were seen when compared with previously reported work. The used nanomaterials could be washed, dried, and reused, which makes the methods more proficient, cost-effective, and environmentally friendly.

Heavy Metal and Mineral Composition of Soil, Atmospheric Deposition, and Mosses with Regard to Integrated Pollution Assessment Approach.

The fact that there are no real borders between the biosphere, atmosphere, lithosphere, and hydrosphere means that environmental pollution monitoring studies should not only include one of the environmental spheres. Thus, integrated environmental pollution assessment studies conducted in the biosphere, lithosphere, and atmosphere promote the "whole system" approach. In this study, the aim was to determine the pollution in the atmosphere, soil, and plants by taking advantage of the high pollution accumulation characteristics of the mosses. Prevailing wind has the potential to distribute pollutants emitted into the air throughout its path. With this regard, soil, mosses, and atmospheric deposition samples were collected in Çanakkale, Turkey, in two seasons. Concentrations of selected elements were measured by Inductively Coupled Plasma-Mass Spectrometry. The enrichment factor of the selected elements in the soil, moss, and deposition samples was calculated. The highest enrichments were found for Lead in atmospheric deposition, Arsenic in soil, and Mercury in moss samples. Cobalt and chromium accumulated more in mosses than in soil. Elevated arsenic levels found in the samples can pose a great risk for public health and agriculture. The study result showed that the elemental composition of the samples was influenced by the enhanced air plume dispersion of anthropogenic pollution sources along the Northeast-Southwest directions due to wind characteristics in the province. As expected, strong correlations were found among the moss, soil, and atmospheric deposition samples indicating the vital interactions between the environmental components.

Geochemical variability in the soils of Bangladesh as affected by sources of irrigation water and inundation land types

Paddy soils in Bangladesh experience extensive irrigation with groundwater and surface water, both having variable geochemical constituents. The soils also have topological variations across the landscape. To understand the geochemical variability in the soils as affected by the different sources of irrigation water and the topographical variability, cultivation zones of paddy soils irrigated with both groundwater (n = 904) and surface water (n = 281) across Bangladesh were sampled and analyzed for a suit of seventeen geochemical elements. This study also assessed the extent and distribution of arsenic and the other geochemical elements in the paddy soils (n = 1209) as well as in a set of neighboring non-paddy soils (n = 235) within the different inundation land types (highland, medium highland-1, medium highland-2, medium lowland, lowland and very lowland) of Bangladesh. The mean concentrations of aluminum (26,000 mg/kg), cobalt (13 mg/kg), copper (32 mg/kg), iron (28,250 mg/kg), lead (18 mg/kg), magnesium (8050 mg/kg), molybdenum (1.02 mg/kg), nickel (41 mg/kg), potassium (4870 mg/kg), sodium (750 mg/kg) and zinc (70 mg/kg) in the surface water-irrigated paddy soils were found to be significantly (0.001 ≥ p ≤ 0.05) higher compared to the concentrations in the soils irrigated with groundwater (23,400; 12; 28; 25,650; 17; 7000; 0.96; 36; 4350; 600; and 62 mg/kg, respectively). Therefore, surface water used for paddy irrigation could increase the inputs of a number of toxic elements in the paddy soils having potential risk of crop contamination. Arsenic in the paddy and non-paddy soils varied significantly (F = 24.74, p < 0.001 and F = 3.42, p < 0.01, respectively) within the inundation land types, the very lowland (9.95 and 6.72 mg/kg, respectively) and lowland (8.33 and 5.20 mg/kg, respectively) having the highest mean arsenic concentrations and the medium highland-1 (5.27 and 5.17 mg/kg, respectively) having the lowest. The concentrations of the other geochemical elements analyzed were also observed to be higher, in general, in the soils of very lowland and lowland. Since the low-level lands are predominantly used for paddy cultivation, higher concentrations of various toxic elements, particularly arsenic, in such soils pose an increased risk of rice toxicity in Bangladesh. The results of this study present an inimitable geochemical database for the surface soils across Bangladesh which can be used in any future studies on the geomorphologically variable agricultural and non-agricultural Bangladeshi soils, providing a basis for environmental pollution assessment and sustainable mitigation approaches.

Assessment of environmental pollution with rare-earth metals through bioaccumulation studies using vegetal bioindicators

Environmental pollution by anthropogenic activities has become a global concern as the release of organic and inorganic pollutants into the atmosphere is responsible for important health problems among the population. The rare-earth metals processing sector has raised particular problems due to the bioaccumulation potential of these metals in the food chain. Urban trees are able to retain pollutants from the environment and can be used as bioindicators also for the rare-earth metal pollution. This paper aimed to assess the bioaccumulation of some rare-earth metals, besides other metals and non-metals, in the foliar part of six urban tree species (Populus nigra L., Populus tremula L., Populus x canadensis Moench, Betula pendula Roth, Aesculus hippocastanum L. and Fraxinus excelsior L.) sampled from different areas of the municipality of Bucharest. Laboratory experiments have shown that all tree species used in the study are able to retain rare-earth metals, but the bioaccumulation capacity is species-specific.

Status, Source and Environmental Pollution Assessment of Some Heavy Metals in Surface Soils of Khuzestan Province

Status, Source and Environmental Pollution Assessment of Some Heavy Metals in Surface Soils of Khuzestan Province

Economic and Environmental Assessment of Environmental Pollution by Construction Companies in Ukraine in the System of Environmental Management in the Post-Pandemic Period

The study's primary purpose is to develop an assessment of the implementation of environmental measures in the system of sustainable development. The development of a comprehensive approach to cost evaluation of environmental innovations allowed to estimate the total cost of the construction project together with environmental and economic damage, choose the most optimal environmental measures for housing, agricultural or road construction, more effectively organise the management system of the construction company. The article considers the importance of making environmental managerial decisions in ensuring society's ecological and economic security. The study proved that construction as a branch of material production is one of the main driving forces of the national economy in terms of results and one of the most potent pollutants. The purpose of environmental and economic assessment of losses from the construction industry is to determine the cost-benefit ratio of the construction project in monetary terms with the mandatory comparison of results before and after the implementation of environmental measures. The analysed ecological and economic indicators of the construction industry, the relationship between the volume of construction work by type of construction products and waste generation by type of economic activity allowed to justify the need for approaches to management decisions in environmental management. The study results can help integrate the requirements for managing the impact of production factors on the ecological and economic condition of the country in order to ensure the safe use of natural resources, environmental protection and economic feasibility (profitability) of management decisions in environmental management.

Three-dimensional quantitative mass spectrometry imaging in complex system: From subcellular to whole organism.

Mass spectrometry imaging (MSI) has been applied for label-free three-dimensional (3D) imaging from position array across the whole organism, which provides high-dimensional quantitative data of inorganic or organic compounds that may play an important role in the regulation of cellular signaling, including metals, metabolites, lipids, drugs, peptides, and proteins. While MSI is suitable for investigation of the spatial distribution of molecules, it has a limitation with visualization and quantification of multiple molecules. 3D-MSI, however, can be applied toward exploring metabolic pathway as well as the interactions of lipid-protein, protein-protein, and metal-protein in complex systems from subcellular to the whole organism through an untargeted methodology. In this review, we highlight the methods and applications of MS-based 3D imaging to address the complexity of molecular interaction from nano- to micrometer lateral resolution, with particular focus on: (a) common and hybrid 3D-MSI techniques; (b) quantitative MSI methodology, including the methods using a stable isotope labeling internal standard (SILIS) and SILIS-free approaches with tissue extinction coefficient or virtual calibration; (c) reconstruction of the 3D organ; (d) application of 3D-MSI for biomarker screening and environmental toxicological research. 3D-MSI quantitative analysis provides accurate spatial information and quantitative variation of biomolecules, which may be valuable for the exploration of the molecular mechanism of the disease progresses and toxicological assessment of environmental pollutants in the whole organism. Additionally, we also discuss the challenges and perspectives on the future of 3D quantitative MSI.

Microplastics Pollution as an Invisible Potential Threat to Food Safety and Security, Policy Challenges and the Way Forward.

Technological advances, coupled with increasing demands by consumers, have led to a drastic increase in plastic production. After serving their purposes, these plastics reach our water bodies as their destination and become ingested by aquatic organisms. This ubiquitous phenomenon has exposed humans to microplastics mostly through the consumption of sea food. This has led the World Health Organization (WHO) to make an urgent call for the assessment of environmental pollution due to microplastics and its effect on human health. This review summarizes studies between 1999 and 2020 in relation to microplastics in aquatic ecosystems and human food products, their potential toxic effects as elicited in animal studies, and policies on their use and disposal. There is a paucity of information on the toxicity mechanisms of microplastics in animal studies, and despite their documented presence in food products, no policy has been in place so far, to monitor and regulates microplastics in commercial foods meant for human consumption. Although there are policies and regulations with respect to plastics, these are only in a few countries and in most instances are not fully implemented due to socioeconomic reasons, so they do not address the problem across the entire life cycle of plastics from production to disposal. More animal research to elucidate pathways and early biomarkers of microplastic toxicity that can easily be detected in humans is needed. This is to create awareness and influence policies that will address this neglected threat to food safety and security.

Index of Atmospheric Purity reflects the ecological conditions better than the environmental pollution in the Carpathian forests

The Index of Atmospheric Purity (IAP) is a popular tool used for the assessment of air quality in polluted urban areas, on the basis of phytosociological data of epiphytic lichen communities. We hypothesized that this indicator could also be used in less polluted forest areas to determine the quality of ecological conditions for lichens. The aim of the present study was to verify the use of IAP method in the assessment of environmental pollution, and alternatively for the assessment of general ecological conditions in protected mountain forests of Gorce National Park (Polish Western Carpathians) based on the epiphytic lichen biota associated with Picea abies. The spatial distribution of IAP values on monitored sites in GNP was compared with: 1) spatial distribution of accumulated sulfur, nitrogen, selected heavy metals, and total heavy metals in Hypogymnia physodes thalli in 1993 and 2018 (30 sites), 2) mean ecological indicator values characterizing species requirements for light (L), substrate reaction (R) and nutrients (N), in 1993, 2013 and 2018 (33 sites). Generalized linear model and redundancy analysis were performed for disclosing most influencing factors affecting lichen communities. The study revealed a few negligible relationships between IAP values and accumulation of such elements as Ni, Mn, Cd, and Cr in both monitoring periods. Simultaneously, IAP can be useful for the identification of forest areas with a high degree of naturalness.

Self-organizing map artificial neural networks and sequential Gaussian simulation technique for mapping potentially toxic element hotspots in polluted mining soils

The application of multivariate geostatistical and statistical methods remain valuable tools for environmental pollution assessment. In particular, stochastic simulation techniques like sequential Gaussian simulation (SGS) and the self-organizing map artificial neural networks (SeOM-ANNs) have facilitated the understanding of the spatial distribution of potentially toxic elements (PTEs) in polluted soils. However, there is a dearth of literature on the application of SGS and SeOM-ANN in mapping potentially toxic elements (PTE) in heavily polluted mining and smelter affected floodplain soils. This study shows the applicability SGS and SeOM–ANN which is a powerful visualization tool for the categorization of PTEs [Cadmium (Cd), Arsenic (As), Antimony (Sb), Lead (Pb) and Zinc (Zn)] levels together with selected soil properties [oxidizable carbon (Cox) and soil reaction (pH_H2O)] in one of the most polluted mining floodplain soils in Europe. A k-means algorithm was used to classify distinct clusters which were visually unclear based on the SeOM–ANN Neighbor distance plot (U-Matrix). The k-means resulted in 5 distinct clusters. Cluster 1 to 5 based on SeOM–ANN for all PTEs revealed an increase in concentration levels in the same order (1–5) while for soil properties the trend was not clear. The soils were successfully assessed based on different intensity level combinations and k-means clustering results efficiently mapped into a spatial distribution map. High concentration levels of the PTEs were noticed in the northern parts of the study area based on the conditional Gaussian simulations (CGSs) generated through SGS, while low levels were prominent in the southwestern parts. The hotspot areas were comparable with the k-means spatial distribution maps. It is recommended that special attention be paid to the identified hotspots for possible remediation. This study further demonstrates the usefulness of geostatistics and advanced statistical methods in site-specific planning and implementation of remediation measures for polluted mining floodplain soils.

Synergic optimization of pollution prevention and resource recovery of secondary lead smelting industry based on two-stage BPNLP network model

Environmental pollution and low resource utilization efficiency caused by pyrometallurgy have seriously restricted the sustainable development of secondary lead smelting industry. A large number of studies focus on the research of hydrometallurgy to replace pyrometallurgy aiming at pollution prevention. However, due to economic cost, quality of secondary lead product and secondary pollution, hydrometallurgy hasn’t been widely applied by now. At present, most of the researches of pyrometallurgy focus on its environmental pollution assessment, or merely focus on the recovery efficiency of secondary lead. There are fewer researches on the synergic optimization methodology of pollution prevention and resource recovery for secondary lead smelting process. BP neural network is a type of model widely used in industrial processes optimization. While the gradient method adopted by the BP neural network often falls into a local minimum. If the fitting function is too complicated, there may be multiple fitting local minima, which will cause great obstacles to practical applications. Therefore, according to the characteristics of secondary lead smelting process, this paper uses a BP neural network-based nonlinear optimization combined with an approximate global optimization method to obtain the optimal smelting parameters. The innovative feature of this paper is that after the first stage of the neural network preprocessing has formed the fitting of the smelting process, the smelting parameters optimization process is carried out based on the fitted neural network model. According to the characteristics of the entire two-stage process, as well as the corresponding conditional constraints and the smoothing process of the BP neural network output function, we have formed a two-stage BPNLP network model with formally unified constraint by adopting the approximate global optimal search method. Compared with the average level of pollution prevention and lead recovery efficiency of pyrometallurgy technology in China, the pollution load Sulphur, lead, arsenic and cadmium in smelting flue gas per unit secondary lead product has been reduced by 78.40%, 52.00%, 72.63% and 16.00% respectively, and the recovery efficiency of lead increased by 8.85%. Thus, the two-stage BPNLP model can achieve the goal of synergic optimization of pollution prevention and resource recovery of pyrometallurgy technology of secondary lead smelting industry which can also provide effective methodological guidance for the related research of other industries.

Preliminary zoning of negative impact of the projected oil waste polygon at the Samotlor field

This paper provides a comprehensive analysis of the building expediency of a polygon for processing oil wastes in KhMAD-Yugra. Preliminary research has shown the environmentally dangerous impact of its project location relative to Nizhnevartovsk city, village Izluchinsk and village Bolshetarkhovo, as well as other important objects. The method of location estimation based on the main rules of life safety is proposed. Its application will reduce the environmentally dangerous impact and make it possible to choose the most optimal location of the polygon. An environmental pollution assessment scale has been developed, presented in tabular form for convenience. The area of zones of different dangerous influence degrees is calculated. The article describes the increase in the probability of earthquakes, wildland fires and floods in the area of the Samotlor field polygon due to global warming. The article also considers the prospect of using GIS programs in modeling environmental phenomena that affect oil and gas production facilities.

Prediction of sediment heavy metal at the Australian Bays using newly developed hybrid artificial intelligence models.

Hybrid artificial intelligence (AI) models are developed for sediment lead (Pb) prediction in two Bays (i.e., Bramble (BB) and Deception (DB)) stations, Australia. A feature selection (FS) algorithm called extreme gradient boosting (XGBoost) is proposed to abstract the correlated input parameters for the Pb prediction and validated against principal component of analysis (PCA), recursive feature elimination (RFE), and the genetic algorithm (GA). XGBoost model is applied using a grid search strategy (Grid-XGBoost) for predicting Pb and validated against the commonly used AI models, artificial neural network (ANN) and support vector machine (SVM). The input parameter selection approaches redimensioned the 21 parameters into 9-5 parameters without losing their learned information over the models' training phase. At the BB station, the mean absolute percentage error (MAPE) values (0.06, 0.32, 0.34, and 0.33) were achieved for the XGBoost-SVM, XGBoost-ANN, XGBoost-Grid-XGBoost, and Grid-XGBoost models, respectively. At the DB station, the lowest MAPE values, 0.25 and 0.24, were attained for the XGBoost-Grid-XGBoost and Grid-XGBoost models, respectively. Overall, the proposed hybrid AI models provided a reliable and robust computer aid technology for sediment Pb prediction that contribute to the best knowledge of environmental pollution monitoring and assessment.

Different bacterial host-based lux reporter array for fast identification and toxicity indication of multiple metal ions

Although luminescent bacteria-based bioluminescence inhibition assay has been widely used in the toxicity assessment of environmental pollutants, the response of a luminescent bacterium usually lacks specificity to a target analyte. Recently, some specific analyte inductive promoters were fused to the lux genes for the purpose of selective bioluminescent sensing, and suits of specific promoters were fused to lux genes to compose a bioluminescent array sensor for simultaneous identification of multiple analytes. However, specific promoter-based methods still suffer from drawbacks including limited selectivity, slow responding time, expensive to construct different promoters involved plasmids, and laborious to find new promoters. Herein, we proposed a novel strategy to construct a lux reporter array sensor by directly transforming the natural lux genes in different bacterial hosts without the involvement of any specific promoters. Due to the distinct pathways of signal production, the responding time of the current different bacterial host (DBH)-based lux reporter array has nearly an order of magnitude faster than with specific promoter-based methods. The DBH-based lux reporter array was successfully used for simultaneous identification, quantification, and toxicity/bioactivity assessment of multiple metal ions. Obviously, all the chemical synthetic material-based metal ion sensing methods cannot simultaneously achieve analysis and toxicity evaluation. This approach possessed additional advantages of facile construction, easy operation, high selectivity, fast response, and strong adaptability to other analytes. A different bacterial host-based lux reporter array was established for simultaneous analysis and toxicity assessment of multiple metal ions.

Eobania vermiculata as a potential indicator of nitrate contamination in soil

The effects of nitrates were analysed on the land snail Eobania vermiculata, a good bioindicator to assess the effects of certain pollutants in soil. It is known that the molluscs are very sensitive to contamination substances and can be used as sentinel organism for environmental pollution assessment. The nitrates are present in fertilizers and in food additives and their excess can not only be harmful to the environment but also dangerous for the humans. Indeed, in the mammals the nitrates are converted into nitrites and can cause a series of complications as the formation of methaemoglobin and cancers. In this study, adult organisms of E. vermiculata were exposed to soil containing 2000 mg/L of nitrates for 30 days to evaluate the stool microbiome and the histological changes at the level of the foot. Eggs of these snails were similarly treated to observe their hatching, survival and development. Histological changes were observed at level of the foot of adult snails exposed to nitrate and in their stools was evident an increase of bacteria, especially those that have a high ability to exploit nitrates and nitrogen as nutrients. Instead, the treated eggs showed changes in hatching, hypopigmentation of newborn snails and a decrease of their survival in time. The overall information obtained from these endpoints can provide important information regarding the quality of the environment. In addition, they also showed that the invertebrate organism E. vermiculata despite being a simple organism is very useful and efficient for ecotoxicological studies.

The potential for salt toxicity: Can the trans-epithelial potential (TEP) across the gills serve as a metric for major ion toxicity in fish?

An emerging Multi-Ion Toxicity (MIT) model for assessment of environmental salt pollution is based on the premise that major ion toxicity to aquatic organisms is related to a critical disturbance of the trans-epithelial potential across the gills (ΔTEP), which can be predicted by electrochemical theory. However, the model has never been evaluated physiologically. We directly tested key assumptions by examining the individual effects of eight different salts (NaCl, Na2SO4, MgCl2, MgSO4, KCl, K2SO4, CaCl2, and CaSO4) on measured TEP in three different fish species (fathead minnow, Pimephales promelas = FHM; channel catfish, Ictalurus punctatus = CC; bluegill, Lepomis macrochirus = BG). A geometric concentration series based on previously reported 96-h LC50 values for FHM was used. All salts caused concentration-dependent increases in TEP to less negative/more positive values in a pattern well-described by the Michaelis-Menten equation. The ΔTEP responses for different salts were similar to one another within each species when concentrations were expressed as a percentage of the FHM LC50. A plateau was reached at or before 100 % of the LC50 where the ΔTEP values were remarkably consistent, with only 1.4 to 2.2-fold variation. This relative uniformity in the ΔTEP responses contrasts with 28-fold variation in salt concentration (in mmol L−1), 9.6-fold in total dissolved solids, and 7.9-fold in conductivity at the LC50. The Michaelis-Menten Km values (salt concentrations causing 50 % of the ΔTEPmax) were positively related to the 96-h LC50 values. ΔTEP responses were not a direct effect of osmolarity in all species and were related to specific cation rather than specific anion concentrations in FHM. These responses were stable for up to 24 h in CC. The results provide strong physiological support for the assumptions of the MIT model, are coherent with electrochemical theory, and point to areas for future research.