Water Pollution Prevention Research Articles

Integrated prediction of water pollution and risk assessment of water system connectivity based on dynamic model average and model selection criteria.

In recent years, with the rapid development of economy and society, river water environmental pollution incidents occur frequently, which seriously threaten the ecological health of the river and the safety of water supply. Water pollution prediction is an important basis for understanding development trends of the aquatic environment, preventing water pollution incidents and improving river water quality. However, due to the large uncertainty of hydrological, meteorological and water environment systems, it is challenging to accurately predict water environment quality using single model. In order to improve the accuracy and stability of water pollution prediction, this study proposed an integrated learning criterion that integrated dynamic model average and model selection (DMA-MS) and used this criterion to construct the integrated learning model for water pollution prediction. Finally, based on the prediction results of the integrated learning model, the connectivity risk of the connectivity project was evaluated. The results demonstrate that the integrated model based on the DMA-MS criterion effectively integrated the characteristics of a single model and could provide more accurate and stable predictions. The mean absolute percentage error (MAPE) of the integrated model was only 11.1%, which was 24.5%-45% lower than that of the single model. In addition, this study indicates that the nearest station was the most important factor affecting the performance of the prediction station, and managers should pay increased attention to the water environment of the control section that is close to their area. The results of the connectivity risk assessment indicate that although the water environment risks were not obvious, the connectivity project may still bring some risks to the crossed water system, especially in the non-flood season.

Perception of water pollution among Malaysian university students: A case study

<p>The present study aimed to understand the perception and knowledge of university students toward water pollution. In the present study, demographic profile, knowledge of water pollution, university students’ perception of water pollution and attitudes towards water pollution prevention were included in the survey questions. This survey on water pollution was conducted among a diverse group of Malaysian university students using Google Forms. The results showed that almost 50% of the respondents have basic knowledge of water pollution, and agreed that industrial activities were the main factor causing water pollution in Malaysia, followed by the accumulation of organic chemical wastes and heavy metals accumulation. It was also revealed that have shown that the water pollution campaign was a key factor to spread awareness among Malaysians and increase knowledge about water pollution problems. The results further confirmed that water pollution needs to be aware of, which showed that respondents were well aware of the water pollution issue in Malaysia and felt obligated to spread awareness and take action towards water pollution regardless of their surrounding community.</p>

Prevention of water pollution through combined sewer overflow using high-speed biofiltration in urban watershed

Over recent decades, the rural areas of Korea, including containing source waters, have become extensively developed. Combined sewer systems (CSSs) have been constructed to collect the sewage generated from these areas. Presently, it is common to experience localized heavy rain events, likely due to climate change, and sometimes, the volume of rainfall can become too high for a CSS to handle. In these cases, combined sewer overflow (CSOs) occurs, contaminating surface water, which may have been used as source water. Therefore, the Korean government will begin regulating the biochemical oxygen demand (BOD) of CSOs occurring during first flushes of less than 40 mg/L from 2024 onwards. In this study, a biofiltration-based technology was proposed to treat CSOs. Thus, this study aimed to remove BOD from CSO using this biofiltration system to contain cube-type media. For this, two different loading rates were tested on a pilot scale. Although the proposed system resulted in a footprint of only 10 % of that of a conventional activated sludge system, it was still capable of achieving efficient BOD removal. At a high loading rate, BOD removal efficiency was observed at approximately 53 %, and when this loading rate was reduced by 50 %, the removal efficiency was slightly improved to about 58 %. In both cases, the BODs of treated CSOs could be maintained below the proposed future standard: 31 mg/L and 28 mg/L for high and low loading rates, respectively. Therefore, the proposed system could potentially be preventing environmental contamination from COSs.

Optimizing Animal Nutrition and Sustainability Through Precision Feeding: A Mini Review of Emerging Strategies and Technologies

Abstract Precision feeding, a practice involving customized diets tailored to individual nutritional requirements, has emerged as a promising paradigm within animal production, underpinned by advanced technologies and data analytics. This mini review embarks on an exploration of the evolutionary trajectory of precision feeding and its profound ramifications on animal nutrition, environmental sustainability, and animal welfare. Prominent technological advancements, exemplified by sensors and automation, have wrought transformative change across various sectors, spanning from dairy farming to poultry production. These technological innovations facilitate real-time monitoring and data accrual, thereby augmenting feed efficiency and fostering animal well-being. Environmental sustainability assumes an integral role in the precision feeding paradigm. Through the reduction of feed wastage and the minimization of nutrient excretion, it serves as a potent mitigating solution against the environmental footprint synonymous with livestock production. This entails a noteworthy reduction in greenhouse gas emissions and the prevention of water pollution. The interplay between precision feeding and animal welfare is intricate and multifaceted. On one hand, it furnishes farmers with the capability to expeditiously monitor and address animal health issues. On the other hand, it poses challenges associated with social interactions and the fulfilment of individualized nutritional needs. The future trajectory of precision feeding is inherently tied to the resolution of imminent challenges, including the imperative for real-time monitoring, the development of cost-effective large-scale implementation, and comprehensive elucidation of long-term effects on animal health and welfare. The ensuing panorama portends promising prospects, encompassing the optimization of resource efficiency, diminution of environmental impacts, and the formulation of personalized nutritional strategies. In summation, precision feeding stands as a domain teeming with potential, poised to optimize both animal nutrition and the sustainability quotient within animal production. Realizing this potential hinge on the adept addressing of forthcoming challenges, coupled with the astute harnessing of emergent technologies, in our collective pursuit of a more sustainable and ethically principled agricultural landscape.

Preparation of Waste Fabric Based Activated Carbon and Determination of Adsorption Performance Using Methylene Blue

The acceleration of industrialisation and population growth throughout the world have caused the rapid depletion of water resources in the last century. Industrial wastes are one of the major factors causing water pollution. One of the most effective and well-known methods to prevent water pollution is adsorption process. In this study, highly porous activated carbons were produced using waste fabric samples and their adsorption performances were determined in the presence an adsorbate to prevent water pollution. Methylene blue (MB) as the adsorbate was used for the adsorption tests. The waste fabric samples were carbonised at 400 °C, 500 °C and 600 °C to determine the effect of pre-carbonisation temperature on the adsorption performance. The activated carbon surface properties varied depending on the pre-carbonisation temperature. The surface areas of the samples were 1385 m2/g, 1583 m2/g and 1276 m2/g, and the total pore volumes were 0.7688 cm3/g, 0.9545 cm3/g and 0.7394 cm3/g, respectively. The results showed that the pre-carbonisation temperature affected the adsorption performance. The adsorption capacities of the activated carbons calculated according to the Langmuir adsorption model were 531.46 mg/g, 630.26 mg/g and 655.40 mg/g, respectively.

DYESTUFF REMOVAL FROM SYNTHETIC TEXTILE WASTEWATER USING OLIVE LEAF

The textile industry is one of the sectors where water use is high. Textile wastewater contains a high percentage of dyestuffs. Dyestuffs prevent photosynthetic activities in water and disrupt the ecological balance in water. Treatment of dyestuffs is very important for the prevention of water pollution and for the health of living things. There are several methods for the treatment of wastewater containing dyestuffs. In this study, it was aimed to remove dyestuff from synthetic textile waste water by using olive leaf by adsorption method. The effects of initial pH, amount of adsorbent, contact time and temperature on adsorption were investigated. According to the data obtained, optimum conditions were determined as pH 2, 0.25 g of adsorbent, 2 hours of contact time, and a temperature of 25 °C. When the experimental data were applied to the kinetic models, it was observed that they conformed to the pseudo-second-order rate equation. The data obtained at the end of the experiments were applied to the Langmuir and Freundlich isotherm models. It was observed that the data obtained with olive leaf conformed to the Freundlich isotherm. The reaction for the olive leaf is an exothermic and occurs spontaneously, according to thermodynamic analysis. Negative entropy indicates a decrease in disorder in adsorption.

Evaluation Model and Application of the Implementation Effectiveness of the River Chief System (RCS)—Taking Henan Province as an Example

To scientifically evaluate the implementation of the River Chief System (RCS), accelerate the overall improvement of the water ecological environment, and promote the sustainable development of river and lake functions, this study selects 26 evaluation indicators from six aspects, including the effectiveness of organization and management, the effectiveness of water resources protection, the effectiveness of water environment management, the effectiveness of water pollution prevention and control, the effectiveness of water ecological restoration, and the effectiveness of the management of the waterside shoreline, and establishes an evaluation system for the effectiveness of the implementation of the RCS. Among the 26 indicators, data for the qualitative indicators mainly come from a series of statistical yearbooks and RCS reports, while data for the quantitative indicators are obtained through scoring by more than 20 experts and calculating the average. The CRITIC objective weighting method is improved from three aspects of comparison intensity, correlation coefficient, and degree of variation, and the subjective weighting of indicators is carried out using the AHP 1–5 scale method. The optimal linear combination of subjective and objective weighting results is obtained using the combination weighting method with game theory, which is auxiliary to the set pair analysis. Considering the “certainty” and “uncertainty” in the evaluation process, the four-element connection number model of set pair analysis is established to evaluate the implementation effect of the RCS in Henan Province from 2018 to 2021. The results show that the implementation effect of the RCS in Henan Province improves year by year and reaches excellent in 2019. The results of this study can be used as a reference for evaluating the work of the RCS in other regions and can also provide a reference for the study of evaluation problems in other fields.

Identifying the influence of natural and human factors on seasonal water quality in China: current situation of China's water environment and policy impact.

Agricultural production, urbanization, and other anthropogenic activities, the major causes of surface water pollution in China, have dramatically altered hydrological processes and nutrient cycles. Identifying and quantifying the key factors affecting water quality are essential for the better prevention and management of water pollution. However, due to the limitations of traditional statistical analysis methods, it is difficult to evaluate the spatial changes and interactions of influencing factors on water quality. In addition, research on a national scale is difficult, as it involves large-scale and long-term water quality monitoring work. In this study, we collected and collated the monthly average concentrations of four water quality parameters, dissolved oxygen, ammonia nitrogen, chemical oxygen demand, and total phosphorous, based on data from 1547 water quality monitoring stations in China. The combined pollution level of the water quality was assessed using the water quality index. Based on the water quality characteristics, water quality monitoring sites in the dry and wet seasons were grouped using k-means clustering. Eleven environmental factors were evaluated using geodetector software, including six human factors and five natural factors. The results showed that there are high-risk areas for water quality pollution in the eastern and southeastern coastal regions of China in both the dry and wet seasons and that surface water pollution in China is highly spatial heterogenous in both the dry and wet seasons. Among the anthropogenic factors, urban land area is the main factor of water quality pollution in the dry season, and the explanation rate of spatial heterogeneity of integrated water quality pollution index is 20.3%. The number of poultry farms and the area of farmland explained 12.4% and 12.1% of the integrated water quality pollution index in the wet season. The nonlinear relationship between these three anthropogenic and natural factors and their interaction exacerbated water quality pollution. Based on this analysis, we identified the key factors affecting surface water quality in China during the dry and wet seasons, evaluated the achievements of the water environmental protection policies in China in recent years, and proposed future management measures for the effective prevention and control of water quality pollution in high-risk areas.

Lead-free and highly-stable double perovskite Cs2SnClXI6-X microcrystals for efficient photocatalytic degradation

In order to protect water bodies and prevent water pollution, the direct use of clean solar energy to degrade the organic dyes in industrial wastewater into innoxious products is a potential strategy and a trending topic. Recently, the lead halide perovskites have been intensively investigated as photocatalysts on account of their unique photoelectric properties. Unsatisfactorily, the lead toxicity and instability of these materials cause irreversible harm to the ecology and low long-term degradation efficiency, limiting their practical applications. For the first time, lead-free double perovskite Cs2SnClXI6-X microcrystals were prepared by solution supersaturation recrystallization method for the photocatalytic degradation of Sudan Red III. The optical band gaps of the Cs2SnClXI6-X microcrystals were adjustable from 4.48 to 1.34 eV upon halogen regulation, while the photodegradation performance of Cs2SnCl4.1I1.9 was even much higher than the recently reported composite photocatalysts under similar conditions. Furthermore, the recycling and storage experiments demonstrated the reusability and excellent environmental stability of the as prepared Cs2SnClXI6-X microcrystals. Based on the results of the free radical trapping tests and electron paramagnetic resonance measurements, the mechanism for the photocatalytic degradation process were discussed in details.

Optimizing city-level centralized wastewater management system using machine learning and spatial network analysis

Access to proper sanitation is a basic human right and a crucial component of public health. Wastewater treatment plants (WWTP) play a critical role in ensuring sanitation access by preventing water pollution. However, in Bandung, one of Indonesia’s strategic cities, only 63% of the population has access to proper sanitation. Therefore, this study aims to identify priority areas for developing a centralized WWTP system using models that consider wastewater production and the availability of sanitation access on a building scale. The novelty of this study lies in integrating wastewater production models and sanitation access availability to prioritize developing WWTP systems at the building level and developing a pipeline model to connect WWTP candidate points with priority building targets. We also analyzed the suitability of optimal WWTP locations to support the development of wastewater treatment systems and determine wastewater pipeline routes using the optimal path method in priority areas. To model wastewater production, we used the number of residents per building and building area as the basis. The availability of sanitation access was modeled by considering the percentage of access per district, identifying urban slums, and analyzing proximity to existing wastewater pipes and rivers. After the modeling process, we classified nine development priority classes. Our results revealed that there is approximately 7.38 km2 of priority area for developing a wastewater treatment system in Bandung which comprises 67,135 priority buildings and 178 potential sites for WWTP. These priority areas are mostly located in the districts of Bojongloa Kaler, Astanaanyar, Batununggal, Kiaracondong, Cibeunying Kidul, Coblong, and Sukajadi. This study’s findings provide valuable insights for policymakers and urban planners to prioritize developing WWTP systems in areas that need them most. It also highlights the importance of considering sanitation access availability and wastewater production models when planning and developing WWTP systems.

The technology of growing rainbow trout in the conditions of PE “Western Fish Company” by feeding Vita Fisch compound feed

A study was conducted on feeding Vita Fisch combined feed to rainbow trout Oncorhynchus mykiss this year based on a full-system cold-water farm of the Western Fish Company, Peremyshlyan district, Lviv region. The experiments considered the conditions of keeping hydrochemical and fishery indicators: stocking density, temperature, oxygen saturation, and pH of the environment. At the initial stages of the work, fish pools with a water volume of 30 m3 were treated by a one-time application of the probiotic “Sviteco PW” at a dose of 1.0 ml/m3 of water. According to our observations, after a day, the water in the pool became more transparent compared to collections without probiotics, which indicates high results of bioremediation, which maintains the water body at an optimal level. By conducting production tests on this year's troy ear we set ourselves the goal of producing high-quality, high-nutrition combined feed with a low cost and feed ratio, which are well eaten by fish, contribute to the appropriate growth rate, increase fish weight, profitability of aquaculture, prevention of water pollution, reduction of manifestations of conditionally pathogenic microorganisms and safety for the environment. Therefore, we fed this year's raiyear'srout with “Vita Fisc” granular compound feed, which is made from domestic ingredients according to a recipe for young trout, in specialized production by fermentation of the main components of the meal with the introduction of 2.5 % of the premix and probiotic “Sviteco PWC” production pools under aquaculture conditions at the 0.7 ml/kg feed. The ingredients and production of this feed are focused primarily on quality indicators regarding environmental friendliness and environmental protection, taking into account health, physiological state, the ability of fish to carry loads, the quality of food fish, and the profitability of production. Feeding with combined feed was carried out at a temperature of 8 °C while providing 1 % of the feed from the weight of the fish during the day. As a result of the work, trout have a high activity in eating, digestibility, assimilation of compound feed, and a low feed coefficient of 0.95 k. units were established.

Does Water Resource Fee to Tax Policy Help Reduce Water Pollution in China?

This research uses a time-varying difference-in-differences (DID) model to assess the impact of the water resource fee to tax (WRFT) policy on water pollution in China from 2004 to 2020. The study finds that the WRFT policy can reduce chemical oxygen demand (COD) emissions by 17.7% and ammonia nitrogen (NH3-N) emissions by 31.6% on average. These findings are supported by various robustness tests, such as the parallel trend test, the placebo test, and the changing standard errors. The study also finds that the impact of the WRFT policy is stronger in regions with higher economic development levels and lower water pollution levels, but does not show heterogeneity in water resource abundance. The mechanism analysis suggests that the WRFT policy achieves the effect of reducing water pollution by reducing sewage discharge, increasing intensity of water pollution prevention, and promoting green R&D innovation. The study addresses potential endogeneity issues such as reverse causality, sample self-selection, and omitting variable bias. Based on these findings, the study offers some policy recommendations to further enhance the WRFT policy effects and reduce water pollution in China.

Spatiotemporal distribution and controlling factors on ammonium in waters in the central Yangtze River Basin, China

High levels of ammonium in water can compromise the ecological environment and be harmful to human beings. It is of great significance to understand the source and controlling factors of ammonium in waters. However, the distribution and controlling factors on ammonium in the central Yangtze River Basin have been rarely reported. The results showed that 6.58% of the surface water (SW) exceeded the China national guideline of category III for NH4+-N (i.e., 1.0 mg/L) and 30.19% of the groundwater (GW) exceeded the China national guideline of category III for NH4+-N (i.e., 0.5 mg/L). Notably, the ammonium concentrations of the plain area in the middle were much higher, which reached to the highest value at the junction of the Yangtze River and Dongting Lake. Nitrogen in SW may originate from manure but more nitrogen sources in GW. The net anthropogenic nitrogen input (NANI) can provide enough organic nitrogen for the mineralization. NH4+-N in SW was more affected by fertilizer nitrogen and feed nitrogen input but more affected by agricultural nitrogen fixation in GW. Agricultural and industrial activities controlled NH4+-N in SW and GW by increasing nitrogen input and changing hydrological conditions. In general, this research exposed the controlling of different types of factors on ammonium in waters, providing a guidance for the water pollution prevention in study area.

Analysis of the Source Tracing and Pollution Characteristics of Rainfall Runoff in Adjacent New and Old Urban Areas

This study aimed to examine the pollution characteristics of rainfall runoff as well as the runoff scouring effect and pollution traceability in adjacent new and old urban areas. The sampling and monitoring of rainfall runoff for different rainfall underlying surfaces were conducted for roads, green spaces, roofs, and a food market. The concentration of chemical oxygen demand (COD) and nutrients in the rainfall runoff of the market area was higher than that measured for roads, green spaces, and roofs. The initial scouring effect of each underlying surface was obvious during rainstorms, and 30% of the runoff transported nearly 50% of the pollutants. Further, 30% of the runoff transported about 30% of the pollutants under moderate and heavy rain conditions, and the overall initial scouring effect was not obvious. The results of this study showed that, as a considered underlying surface area, the market and possibly other similar service facilities had a significant impact on the calculation of runoff pollution load, and these should be included in the research scope of rainfall runoff and the impact of underlying surfaces. The purpose of this study was to provide reliable and practical information for water pollution prevention and control, especially for pollution prevention and control of rainfall runoff in areas where new and old urban parts of cities exist side by side.

Estimating Unconfined Aquifer Diffusivity Using 1D Phase Spectral Analysis: A Case Study in the Middle Reach of the Hutuo River, North China Plain

Aquifer diffusivity is a basic physical parameter used in hydrogeological calculations and is important for the evaluation and rational utilization of water resources, pollution prevention, and wetland protection. In this study, with the assumptions of aquifer isotropy, i.e., no vertical flow and constant saturated aquifer thickness, by using the Fourier transform and convolution theorem, a 1D analytical solution of the phase spectrum for an unconfined aquifer system was derived, which subsequently led to a phase spectrum solution for aquifer diffusivity. To test the efficacy, the proposed method was applied to a study site in the middle reach of the Hutuo River in the North China Plain. The estimated aquifer diffusivity ranged from 1.9 × 103 to 4.9 × 104 m2/d, with a mean of 2.2 × 104 m2/d, which was consistent with the results obtained using power spectral analysis, pumping tests, and inverse numerical models. The phase spectral approach proposed in this paper can estimate the aquifer properties on a larger scale. If long time series of hydraulic heads are available, it can estimate hydrogeological parameters accurately and quickly. Considering the similarity of the linearized governing equations, it can also be applied to the river–aquifer system and the confined aquifer system.

Analyzing the Pollution Sources and Mechanisms of Urban Rivers Based on Identifying the Molecular Signature of Dissolved Organic Matter

Dissolved organic matter (DOM) is an essential component of river pollutants. Under the new situation of black water treatment in urban areas of China, in view of the widespread problem of unclear sources of multiple pollutants, further analysis of DOM components in urban rivers from the molecular level is a key link to deeply explore the sources, causes, and mechanism of river pollution so as to achieve efficient management. In this study, the urban rivers in the central city were selected as the research object, and a total of five rivers were selected that were seriously affected by the discharge sewage of four combined and separated sewer systems, respectively. Using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), this study identified the molecular formulae and analyzed the elemental composition and compound groups of DOM in water and sediment samples at each site in dry and wet weather. The results showed that:①although CHO molecules and lignins were the main compounds in the urban river DOM, the high proportion of lipids, proteins, and heteroatomic compounds (especially CHOS molecules) revealed the anthropogenic pollution in rivers, which also led to the increase in DOC, TN, and NH+4-N. ②Surfactants such as C17H28O3S and C18H30O3S were ubiquitous in all urban rivers, which could be used as markers of domestic wastewater pollution. ③In wet weather, the rainfall inputs, storm runoffs, and hydraulic disturbance jointly led to the increase in the proportion of CHO molecules and lignin compounds; the decrease in proteins and lipids; the rise of DOC, TN, and NH+4-N concentrations in river water; and the decrease in DOC, TN, and NH+4-N concentrations and proteins and lipids in river sediments. ④The abundance of multi-heteroatomic compounds and condensed aromatics in the combined sewer system was higher than that in the separated sewer system, which may have been more severely polluted by domestic wastewater and storm runoff, especially kitchen wastewater. This study provides new insight for clarifying the critical causes of pollution in the new stage and provides an essential basis for further precision prevention and control of water pollution.

Exploring the contribution of the river chief system on controlling industrial water pollution under quasi-natural experimental conditions.

The innovative environmental system known as the river chief system (RCS) was developed in China to limit water pollution by appointing provincial, prefectural, county, and township officials as "river chiefs" as guardians of every river under their control. Our research project developed a quasi-natural experiment to investigate if the RCS effectively reduces the intensity of industrial water pollution. A multi-period difference-in-difference (DID) method was employed in the experiment with a total of 3808 samples from 272 prefecture-level cities. The samples gathered represented the years from 2007 to 2020. Our results demonstrated that the southern region has far more industrial water contamination than other locations, and the intensity of industrial sewage discharge decreased by 10.25% in pilot cities following the implementation of the RCS compared with what we observed in non-pilot cities. Furthermore, according to the mechanism analysis we used, cities that increased investment in technical advancement and modernized industrial structures may also account for this decreasing trend. Additionally, the results of geographical heterogeneity demonstrate that the RCS's influence on curbing industrial water pollution is greater in cities with a higher intensity of environmental regulation and higher fiscal balance pressure than in locations with low environmental regulation and low fiscal balance pressure. In summary, the Chinese government needs to continue to strengthen the RCS's implementation; this can be done by adjusting to local circumstances as needed and by carrying out the policy accurately and effectively across the country. Our research sheds light on how to prevent water pollution in China and in other countries and supports the positive effects and effectiveness of RCS.

Spatial Distribution of Nitrogen and Phosphorus Nutrients in the Main Stream and Typical Tributaries of Tuojiang River and Fujiang River

The Tuojiang River and Fujiang River, two important tributaries of the upper reaches of the Yangtze River, have serious water pollution problems, among which nitrogen (N) and phosphorus (P) are the most important pollutants. Therefore, the aim of this study was to identify the influencing factors of water quality in different spaces and provide a scientific basis for the prevention and control of surface water pollution in the upper reaches of the Yangtze River and its tributaries. Water samples of trunk and tributaries in the Tuojiang River and Fujiang River were collected, and the spatial distribution characteristics of water N and P were analyzed. The results showed that the Tuojiang River and Fujiang River showed serious pollution of total nitrogen (TN), with a water quality worse Ⅴ-section proportion as high as 94% and 50%, respectively. Both rivers showed that TN and TP concentrations in the tributaries were higher than those in the main stream. For both rivers, total phosphorus (TP), with moderate pollution, was mainly concentrated in Ⅱ, Ⅲ, and Ⅳ class water quality, whereas the P pollution was more serious for the Fujiang River compared to that of the Fujiang River. For the Tuojiang River, nitrate nitrogen (NN) concentration from upstream to downstream showed a trend of decreasing after the first increase, with the maximum concentration of ammonium nitrogen (AN) exhibiting at the upstream site. In particular, TP concentration increased significantly after rivers flowed through a city. For the Fujiang River trunk stream, TN and NN concentration exhibited a gradually increasing trend from the middle to lower reaches. Generally, our study revealed that TN, TP, and NN in the rivers were affected by water pH and water temperature (T). Therefore, the control of N and P pollution in rivers should pay attention to the influence of water environmental factors.

Source apportionment of heavy metal(loid)s in sediments of a typical karst mountain drinking-water reservoir and the associated risk assessment based on chemical speciations.

As important place for water storage and supply, drinking-water reservoirs in karst mountain areas play a key role in ensuring human well-being, and its water quality safety has attracted much attention. Source apportionment and ecological risks of heavy metal(loid)s in sediments of drinking-water reservoir are important for water security, public health, and regional water resources management, especially in karst mountain areas where water resources are scarce. To expound the accumulation, potential ecological risks, and sources of heavy metal(loid)s in a drinking-water reservoir in Northwest Guizhou, China, the surface sediments were collected and analyzed based on the combined use of the geo-accumulation index (Igeo), sequential extraction (BCR), ratios of secondary phase and primary phase (RSP), risk assessment code (RAC), modified potential ecological risk index (MRI), as well as the positive matrix factorization methods. The results indicated that the accumulation of Cd in sediments was obvious, with approximately 61.9% of the samples showing moderate to high accumulation levels, followed by Pb, Cu, Ni, and Zn, whereas the As and Cr were at low levels. A large proportion of BCR-extracted acid extractable and reducible fraction were found in Cd (72.5%) and Pb (40.3%), suggesting high bioavailability. The combined results of RSP, RAC, and MRI showed that Cd was the major pollutant in sediments with high potential ecological risk, while the risk of other elements was low. Source apportionment results of heavy metal(loid)s indicated that Cd (75.76%) and Zn (23.1%) mainly originated from agricultural activities; As (69.82%), Cr (50.05%), Cu (33.47%), and Ni (31.87%) were associated with domestic sources related to residents' lives; Cu (52.36%), Ni (44.57%), Cr (34.33%), As (26.51%), Pb (24.77%), and Zn (23.80%) primarily came from natural geological sources; and Pb (47.56%), Zn (22.46%) and Cr (13.92%) might be introduced by mixed sources of traffic and domestic. The contribution ratios of the four sources were 18.41%, 36.67%, 29.48%, and 15.44%, respectively. Overall, priority control factors for pollution in relation to agricultural sources included Cd, while domestic sources are primarily associated with As. It is crucial to place special emphasis on the impacts of human activities when formulating pollution prevention and control measures. The results of this study can provide valuable reference and insights for water resources management and pollution prevention and control strategies in karst mountainous areas.

In-Situ Leaching Mining Technique for Deep Bauxite Extraction and the Countermeasures for Water Pollution Prevention: An Example in the Ordos Basin, China

As the second most significant metal following steel, aluminum plays a vital role in the advancement of both strategic emerging industries and national economic development. The existing oil and gas drilling data indicate that the deep bauxite deposits is abundant around the Ordos Basin in China, at the depths ranging from several hundred meters to several kilometers. Based on the geological and hydrogeological characteristics analysis, it is found that deep bauxite deposits in the basin have distinct electrical characteristics, characterized by four highs and two lows. While there is scarcity of prior research on the exploration topic for the technique limitation. In this paper, a logging interpretation model has been developed, which allows the evaluation of bauxite deposits. An efficient technology was proposed for deep bauxite exploration, utilizing an in-situ leaching mining technique. This technology is well-suited to the geological conditions of the Ordos Basin, ensuring that the solution flows within the bauxite ore bed without any seepage loss. To prevent the leaching solution from seeping into and polluting the main aquifer around the basin, several measures have been proposed. These include filling with polymer resin, well pattern seepage control plugging, and establishing monitoring systems. The results of this study provide a theoretical basis for the adoption of environmentally sustainable mining techniques and the mitigation of water pollution in deep bauxite exploration.