Water Quality Standards Research Articles

Water Quality and Prevalence of Extended Spectrum Beta Lactamase Producing Escherichia coli (ESBL E. coli) in Sungai Terengganu, Malaysia

Antimicrobial resistance (AMR) is a significant global issue impacting human, animal, and environmental health, as well as economic security. Water bodies, especially, are now recognized for their role in the spread of antimicrobial-resistant pathogens, though standardized monitoring methods are lacking. This study investigates the presence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli in the Sungai Terengganu River in Malaysia, focusing on water quality and ESBL E. coli monitoring. Sampling was conducted twice in 2023 at 13 locations along the river. Overall, the water quality index (WQI) classified the river as Class II (WQI = 81), with upstream regions rated as Class I, indicating minimal anthropogenic impact. Higher Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS) in downstream areas suggested organic pollution from anthropogenic activities. Four metal elements exceeded the National Water Quality Standards (NWQS): Al (0.88 mg/L), Fe (3.45 mg/L), Cu (0.102 mg/L), and Hg (2.525 mg/L). No Pb, Cr, Se, Sn, or As were detected. Statistical analysis showed better water quality correlates with lower microbial contamination. ESBL E. coli was found in 8 of 13 sampling sites (61.5%), with the highest concentration at 800 CFU/100 mL. From 40 presumptive ESBL isolates tested, 87.5% (35 isolates) were positive for ESBL and carried additional drug resistance genes, including mcr-1, tetW, sul-1, and sul-2. These findings indicate a concerning presence of multidrug-resistant E. coli in the river, representing a potential public health risk.

Multi-stage ecological pond and reservoir system to enhance river water quality: demonstration study on Periurban River

ABSTRACT Pollution of urban rivers not only destroys the river ecology but also adversely affects the health of residents and urban landscape. In this regard, we selected a certain river in Wuhan for research. In this paper, we utilize the modified bypass multi-stage ecological pond reservoir system, set up the front parthenogenetic pond, aeration and oxygenation pond, ecological purification pond and other processes, supplemented with aeration–bacteriophage coupling, filler-type ecological floating island and other technologies to improve the water quality of the river. Results show that 4 months after the operation of the system, the rate of enhancement in water transparency reached 550%, and with a dissolved oxygen (DO) uplift rate of 322%, in addition, this system achieved 77.98, 77.78 and 74.41% removal of the ammonia nitrogen (NH3-N), total phosphorus (TP), chemical oxygen demand (COD) respectively, and the effluent water quality meets the target water quality standard. The process not only has a good pollutant removal effect, low cost and other characteristics but also can enhance the river landscape and improve biodiversity. It can provide a reference for similar river pollution water quality improvement.

Fabrication of FeCu/CC Composite for Efficient Removal of Nitrate for Aqueous Solution Via Electrochemical Reduction Process

AbstractThe electrochemical nitrate reduction (ENR) for the conversion of nitrate to nitrogen gas is a significant strategy to remediate the eutrophication in surface water. However, the exploitations and practical applications of suitable electrocatalysts still face great challenges. In this study, FeCu bimetal microparticles were deposited onto surface of carbon cloth (CC) to fabricate the FeCu/CC electrocatalyst for the removal of nitrate. Among obtained catalysts, the sample with Fe/Cu molar ratio of 1 : 15 (Fe1Cu15/CC) exhibits the excellent electroreduction efficiency for nitrate removal (R(NO3−), >90 %) but an ineffective selectivity of N2 formation (S(N2), ~23 %). After the anchor of reduced graphite oxide (rGO) to surface of Fe1Cu15/CC, at the optimized condition without the assistance of chlorine oxidation, R(NO3−) and S(N2) of rGO/Fe1Cu15/CC catalyst reach 94.2 % and 72.8 %. After 5 day endurance test, the values of R(NO3−) and S(N2) are still 82.9 % and 62.8 %, demonstrating the promising durability of this catalyst electrode. Meanwhile, the potential application of rGO/Fe1Cu15/CC was explored for the treatment of simulated wastewater discharged by urban wastewater treatment plant, the concentration of total nitrogen (TN) decreases from 15–1.17 mg/L, and this value is lower than TN threshold limit in Class IV of Chinese surface water quality standard.

Somatic coliphages as bioindicators of contamination in Lake Guamuez, Colombia

Lake Guamuez is the second largest lake in Colombia and economically supports hundreds of families in the area. The main activities carried out in the region have focused on tourism, agriculture, livestock, and rainbow trout production; however, these activities have been associated with contamination of the lake. This research aimed to evaluate the water quality of Lake Guamuez using somatic coliphages (SCs) as bioindicators. For this purpose, periodic sampling was carried out for six months at 9 strategic points of the lake. For the detection of SCs, the method described in 9211 D of the Standard Methods for the Examination of Water and Wastewater was used. The genomic variability and presence of virulence genes in the isolated SCs were determined. Water contamination in the lake is evident, and the SCs titer is greater in areas with a high flow of anthropogenic activities. An important degree of genetic diversity and a high prevalence of virulence genes could be observed among the SCs analyzed. The results when compared with guidelines and water quality standards from various countries, showed concentrations of SCs higher than those allowed. The high prevalence of gastrointestinal diseases in the region suggests a link to water contamination.

Evaluation of water quality and heavy metal contamination in Cauvery River: Tamil Nadu region India

Abstract Comprehensive water quality control is a fundamental requirement for environmental preservation and the sustainable development of communities around the globe. To showcase the importance of local quality controls in identifying the sources of pollution, a case study was conducted to analyze the quality of drinking water from different locations along the Cauvery River from Mettur to Trichy (200 km) in Tamil Nadu, India. The quality of water samples from different locations was indexed and compared with the World Health Organization and Indian Standards of water quality. The results indicate some high local values of TDS, hardness, and chloride content. These high values may be due to effluents from industries, dying factories, and sewage from the urban areas on the banks of the Cauvery River. This is most prevalent near Mohanur, where industrial waste and effluents were directly linked into the river. The results emphasize the importance of local quality control for accurately pinpointing the factors affecting the environment.

Assessment of radiological risk to workers and members of the public from the operation of a groundwater treatment plant in Jordan

ABSTRACT The study aimed to evaluate the radiation doses received by workers at a pilot water treatment plant (WTP) in Jordan. It also examined the concentrations of gross alpha, gross beta, and radium activities in both groundwater and treated water, along with a radiological risk assessment for the waste generated by the treatment process. The radioactivity levels of gross alpha and gross beta in the groundwater were found to exceed the established drinking water limits. In the pilot WTP, two methods were applied for water treatment, namely, ceramic ultra-filtration (CUF) and reverse osmosis (RO), both of which produced treated water that met drinking water quality standards. The annual effective dose from external radiation exposure to the WTP workers was found to be less than 0.007 mSv y−1 (during the filters backwash operation). However, the average annual dose from internal radiation due to inhalation of radon released from groundwater reached 3.2 mSv y−1, exceeding the 1 mSv y−1 limit. Therefore, monitoring radon levels in workplaces is recommended. Radioisotope concentrations in the waste (sludge) stockpiles exceeded clearance levels, requiring them to be treated as radioactive waste. Overall, the WTP successfully produced drinking water that met quality standards, and the methods used could be replicated in other locations.

Real-time water quality monitoring along the lower stretch of River Ganges and its connected drains using sensors and Water Quality Index

ABSTRACT In this study, water quality is measured using a Real-Time Water Quality Monitoring System for a total of 84 times at 14 locations, in which four drains discharged sewage directly to river Ganges at Bihar, five locations on river Ganges at West Bengal, two tributaries of river Ganges at West Bengal and three drains discharged wastewater directly to river Ganges at West Bengal. In Bihar, four major drains discharged 377.98 MLD wastewater into the river Ganges which in turn released 8985.17 kg of BOD per day. In West Bengal, three major drains had a total flow of 1630.88 MLD that discharged 11563.77 kg of BOD per day to the River Ganges. The average Water Quality Index of the river Ganges was observed as 64.55 and that of drains of West Bengal and Bihar were recorded as 309.78 and 775.56, respectively. The average BOD to COD ratio of less than 0.6 indicated wastewater from drains of Bihar and West Bengal was nonbiodegradable. DO and pH values were recorded compliant with the bathing water quality standard at all river locations, however, the average BOD value at five monitoring points of the river Ganges and its tributaries was slightly above the bathing water quality standard.

Assessment of Groundwater Quality Using Water Quality Indices in Illegal Mining Communities: A Case Study of the Atwima-kwanwoma District and Obuasi East Metropolis, Ghana

This study investigated groundwater quality in illegal mining zones within the Atwima-Kwanwoma District and Obuasi East Metropolis of the Ashanti Region, Ghana, employing both the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) and Nemerow's Pollution Index (NPI). The analysis revealed severe contamination across multiple parameters, including heavy metals, microbial indicators, and physicochemical parameters. The CCME-WQI values for the five towns consistently indicated "Poor" water quality, ranging from 26.8 to 31.1, reflecting significant deviations from acceptable water quality standards. Notably, Town A exhibited a cyanide concentration of 11.25 mg/L, while Town B recorded lead levels at 118.73 μg/L, both far exceeding permissible limits set by health authorities. The presence of Escherichia coli further exacerbates health risks, underscoring the urgent need for improved water treatment and management practices. This study demonstrates that the integrated use of NPI and CCME-WQI provides a comprehensive assessment of groundwater quality, revealing significant environmental and public health challenges. Immediate intervention, including regulatory enforcement, sustainable mining practices, and remediation strategies, is crucial to safeguard groundwater resources. The findings contribute uniquely to the understanding of water quality dynamics in mining-affected regions and advocate for a coordinated approach to mitigate environmental degradation.

Evaluations of Groundwater Quality using Principal Component Analysis and Associated Multivariate Techniques: A Case History in Ewekoro Communities, South-West Nigeria

The quest for quality water consumption is comprised of integration of numerous techniques from different professionals whose contributions go a long way in determining overall health status and wellness of any given society. The water quality status of boreholes in Ewekoro communities of Ewekoro Local Government Area, South-West Nigeria was investigated in this work. Water samples were collected from 25 boreholes at various sampling stations across the study area. Standard analytical water quality methods using Inductively Coupled Mass Spectrometry (ICP-MS)/Optical Emission Spectrometry (ICP-OES) and Pour Plate Techniques were respectively employed in the laboratory for the samples’ geochemical and bacteriological analyses. The raw data were processed and analyzed using Principal Component Analysis and other multivariate techniques with Excel and SPSS 20.0 statistical software packages with the corresponding outcomes systematically compared with water quality standards. For the PCA, the varimax rotation converged in 23 iterations with 6 components extracted which accounted for 92.76% of the total cumulative variance respectively observed for geochemical parameters. Na2+, K+, Ca2+, Cl-, SO42-, NH4+, PO43-, and HCO3-, Mg3+, Cu2+, Cd2+, Zn2+, Ni, S , Si, Fe3+, NO3− and Al3+ played a significant contribution with higher factor loading supported by the dominance of HCO3− among the water quality determinants. The rotation converged in 8 iterations with 3 extracted components that accounted for a total cumulative variance of 90.99% % with pH, TEMP, EC, BOD, TS, TURB, ALK, TH, TDS, THC, and DO in the Physico-chemical Parameters series. Most quality determinants in the sampled water are within allowable limits of the approved water quality standards including WHO except Alkalinity, HCO3−, MgCO3−, Cl−, BOD, Cd2+, Fe3+ and Zn2+. The overall ionic dominance pattern follows the same trend K+ >Na2+ > Fe3+ >Mn2+ and Cl- >NO3- >NO2-. The results of the microbial analyses revealed the highest Total Coliform Count of 17 x 102 MPN/100 ml while that of THBC and FCC were reported as 7.8 ×102 cfu/ml and 1.2×102 cfu/ml respectively. The hygienic status of the water sources was found to be poor. High BOD, Coliform Count and BOD5:NO3- ratios of 248.23 recorded for the groundwater samples were suggestive of possible organic pollution due to faecal invasion with the lowest measured depth of 35m. Multivariate statistical approaches namely Correlation, Principal Component Analysis and Descriptive statistics simplified and identified the interrelationship among the analyzed physicochemical parameters and the pollution sources. This study has therefore revealed that boreholes in Ewekoro were polluted and posed potential risk to biomedical safety and overall human health. Intervention measures are therefore necessary to safeguard the inhabitants from water-related diseases and their consequences.

Key Issues and Challenges in Establishing Regionally Differentiated Water Quality Standard in China

The goal of environmental management in China is transitioning from pollution control to the improvement of ecological quality. The establishment of regional differential water quality standards can better adapt to the ecological characteristics and development needs of different regions. Given the shortcomings of current water quality standards and the needs of technological development, this study analyzed the causes and influencing factors of regional differences in water quality standards and summarized China's regional variations in areas such as the characteristics of receiving water bodies, social attributes, climate conditions, physicochemical properties of water, and aquatic biotic populations. It also examined the impact of regional characteristics on the assessment of biological toxicity. Based on these analyses, the study identified key scientific questions that may arise in the development of regional differential water quality standards in China and outlined future critical research directions in this field. These directions include developing theories and methods for determining the effluent dilution coefficient, establishing methods for identifying regional key water quality indicators and assessing their impact on water quality standards, determining regional characteristic species and their influence on water quality standards, and formulating theories and methods for categorizing different regions across the country. The aim of the study was to provide a reference for the scientific establishment of water quality standards in China.

Influence of Typical Regional Land Use/Landscape Pattern on Water TN of the Upper Yellow River

This study aimed to explore the relationship between land use landscape pattern and water quality in the upstream of the Gansu water conservation, water and soil erosion, and ecological fragile areas. Based on the land use data and water quality monitoring section in 2020 in the 200 m, 500 m, 1 km, 2 km, 50 km, and 10 km riparian buffer area, the single-factor index evaluation method, random forest regression model, and BP neural network were used to quantify the response relationship between land use and landscape pattern of the upper Yellow River in Gansu province and water quality index and to carry out the basin water quality prediction based on land use landscape index data. The results showed that： ① through the single-factor index method, the major indicators of the total nitrogen （TN） in July and September, dissolved oxygen （DO）, permanganate index, ammonia nitrogen （NH4+ -N）, total phosphorus （TP）, and other surface indexes met the surface water environment class Ⅲ water quality standard. ② The random forest regression model was used to analyze the influence of land use and landscape index on TN, and the difference in TN in different typical areas was obtained. The land use types with the highest influence on the TN index in water conservation areas, soil and soil erosion areas, and ecological fragile areas were cultivated land, grassland, and construction land, respectively. ③ The BP neural network was used to predict the water quality index based on different typical areas of land use landscape index. The result of water conservation areas was good, the error rate between the predicted value and the actual value was below 10%, and the prediction accuracy was high. The study showed that water quality prediction based on land use and landscape index/water quality quantitative relationship model had a good water quality prediction effect.

B-174 Quantification of vitamin C in serum as a biomarker using the Laser Diode Thermal Desorption technique “LDTD”/Mass Spectrometry (Luxon)

Abstract Background Ascorbic acid (AA) or vitamin C, is a crucial substance that is involved in numerous physiological processes in living beings, including collagen production and antioxidant activity. When ascorbic acid is exposed to moisture, air, heat, light and oxygen, it oxidizes and turns into dehydroascorbic acid (DHAA). Our objective is to describe the sample preparation procedure and total quantification of AA and DHAA in human serum sample based on LDTD-MS/MS, and demonstrate its efficiency in quantification, combined with analysis selectivity and rapidity. Methods The Luxon is a sample introduction and ionization source that used a fiber-coupled laser diode to thermally desorb neutral molecules and charge them using a corona needle so they can be analyzed by mass spectrometry. Due to the instability of ascorbic acid, plasma samples were enriched and stabilized with an acidic solution. Sample preparation utilized a phosphate-containing buffer to minimize interferents and help volatize the analyte, followed by a precipitation step using acetonitrile to further clean the extract. Stable isotope-labeled internal standard (13C6 ascorbic acid) and homemade calibration curve and water quality controls were used for quantification. The analysis was performed using a Sciex 6500+ Triple Quad in APCI (Atmospheric Pressure Chemical Ionization) negative mode. Calibration curves ranging from 1 to 100 μg/mL and QCs were prepared in ascorbic acid-depleted serum (kept at room temperature/exposed to light for 4 days). The peak area against the internal standard (IS) ratio was used to normalize the signal. The calibration curves were plotted using the peak area ratio and the nominal concentration of standards. The following parameters were assessed for quantitative analysis: linearity, precision, accuracy, carryover and parallelism. A linear regression model with 1/X2 weighting was used to obtain the calibration curve equation and determine the correlation coefficient (r2). Parallelism was assessed by comparing the correlation coefficient of calibration curves prepared in water to six curves prepared with biological matrixes. Intra and inter assay precision and accuracy were determined by measuring QC samples ranging from low to high concentration in five replicates for 3 consecutive days. Results Calibration curves (n=3) showed excellent linearity. The calibration curve resulted in a linear response throughout the concentration range, the correlation coefficient was 0.99. For each quality control concentrations CVs were <10% complying with desirable specifications for imprecision and accuracy. Intra-assay CVs were 3.0-8.89% and inter-assay CVs were 7.64-9.79% for precision which reflects the agreement between repeated measurements. The results for accuracy showed similar results, intra-assay CVs were 3.83-9.20% and inter-assay CVs were 5.0-9.7%. Conclusions The new LDTD-MS/MS method described here has been validated as an effective technique to reliably and rapidly quantify ascorbic acid. Simple sample preparation, rapid acid stabilization combined with high yield allow analysis without degradation responses.

A modified robustness index for assessing operational performance of drinking water treatment plants: a comparative study within a new regulatory framework

Drinking water treatment plants (DWTPs) are facing emerging challenges affecting raw water quality. In addition, the new regulatory framework (EU 2184/2020) sets stricter limits for turbidity and percentile statistics for continuous compliance, demanding greater robustness of the treatment processes. To achieve this aim, this study proposes a turbidity robustness index (TRI), named TRI95B, to be used as a warning tool for detecting deviations from water quality standards. TRI95B has been compared with the TRIs existing in the literature. Furthermore, the TRI95B validation has been performed by a three-year monitoring dataset of a full-scale DWTP. The proposed TRI95B index has two key novelties compared to the existing indices required for adapting to the new drinking water regulation: i. introduces the 95th percentile as a statistical indicator; ii. considers an additional term that sets an alert when a threshold value is exceeded.The comparison results suggest a better correspondence to the real plant performances of TRI95B than the other TRIs. Indeed, both the sensitivity and specificity of TRI95B were significantly higher than the other TRIs, indicating a better capacity to correctly classify both positive and negative cases. Moreover, while the previous TRIs identify a critical operating condition when the turbidity goal was significantly exceeded, TRI95B highlights a failure condition at a lower discrepancy. Therefore, TRI95B is also able to identify short-duration and low magnitude failures, thus coping with the purpose of the new regulation for drinking water.

First full-scale application of barium carbonate as an effective dispersed alkaline substrate for sulfate removal from acid mine drainage

A full-scale passive treatment plant using barium carbonate (BaCO3), the mineral witherite, as a Dispersed Alkaline Substrate (DAS) for strongly contaminated acid mine drainage was implemented for the first time globally at Mina Concepción, located in the Iberian Pyrite Belt (SW Spain). The plant was monitored over a 105-day period, covering the wettest months of the hydrological year and with a mean flow around 4 L s−1. The AMD treated in the plant exhibits a high strength, with an average sulfate concentration around 1500 mg L−1 and net acidity close to 1000 mg L−1 as CaCO₃ equivalent. According to the above, the loading rate for SO4 and Fe was around 400 and 80 kg day−1, respectively. The treatment process produced an alkaline effluent with low metal content. Nearly complete removal of most metal(loid)s was achieved, with significant sulfate decrease to below 500 mg L−1 in the alkaline outflow of the barium carbonate tank. Barium carbonate demonstrated superior performance compared to magnesia, particularly in enhancing alkalinity and lowering net acidity and concentrations of sulfate and manganese. The high efficiency attained by the plant after the barium carbonate treatment is evidenced by compliance with environmental water quality standards for most contaminants.

Spatiotemporal evolution of the physicochemical parameters of the waters of the Oum Errabiaa watershed dams (Morocco)

This study was conducted to determine the characteristics of the physicochemical parameters of the water of the dams of the Oum Errabiaa watershed during flood and low water periods. Data were collected by water sampling and measurements performed in the various dams from 2016 to 2021. The results showed that the water temperature varied from 11.77 °C to 30.20 °C, depending mainly on the sunshine. The water was alkaline with an average pH of 8.23 and had a weak to high electrical conductivity (143-3180µS/cm). The water was relatively well oxygenated at the surface and oxygen depleted in depth (1.44 – 15.04mg/L). The average concentration of suspended solids (SS) was 19.76mg/L, indicating that the dam water is relatively unpolluted. The average values of nutrients, NH4+, NTK and NO3- of 0.18mg/L, 0.53mg/L and 3.51mg/L, respectively, were in compliance with the WHO guidelines for drinking water production. The average concentration of SO42- was 90.60mg/L, which is considered high, exceeding the World Health Organization (WHO) water quality standard of 50mg/l. The average chlorophyll a was 5.51µg/L, which is considered to be low to moderate in dams. Overall, the Oum Errabiaa’s water dams of watershed have good physicochemical quality, except for the high concentration of sulfates. This pollution is likely due to agricultural and industrial activities in the watershed. The use of multivariate techniques (ACPN) enabled us to define the origin of nutrients through surface inputs, on the one hand, and through the photosynthetic activity of cyanobacteria, on the other hand.

Model of environmental management due to coal mining on the Separi River in Tenggarong Seberang District, Kutai Kartanegara Regency, East Kalimantan Province

Coal mining has a significant impact on reducing river water quality. The decline in river water quality causes problems for human life and the environment. Therefore, this research aimed to evaluate river water quality and develop strategies for improving river water quality due to open pit coal mining activities in Tenggarong Seberang District and develop environmental improvement strategies. Several chemical parameters, including pH, TSS, Fe, and Mn, were observed through laboratory tests to determine water quality in the Separi River used in coal mining. The next step was determining environmental improvement strategies using the ISM approach. Twenty stakeholders from related agencies and institutions using FGD were involved in developing a policy strategy. The results of the analysis showed that there has been a decrease in river water quality standards due to mining activities in the research area, and the quality is still below the standard quality. Therefore, two significant strategies must be a priority for the environmental management of the Separi River. First, Conducting an environmental audit of the factors causing the decline in river water quality is necessary. Second, there must be warnings and legal sanctions for negligence in oil spills and oil used from coal mining.

Synthesis of Copper-Doped Metal Nanoferrites for Efficient Removal of Pharmaceutical Wastewater Pollutants in Membrane Bioreactor System

Pharmaceuticals present in the aquatic environment can poison aquatic species and humans through drinking water and cause harmful bacteria to become resistant. The role of transition metal doped metal nanoferrites for the enhanced efficiency of degradation process is widely achieved. In this work, copper doped magnesium ferrite (Cu-MgFe2O4) and copper doped zinc ferrite (Cu-ZnFe2O4) nanoparticles were synthesized using a sol-gel method. X-ray diffraction (XRD) analysis confirmed the formation of the spinel structure for both samples, with crystal sizes of 16.72 nm and 59.05 nm, respectively. The magnetic properties of the samples were studied using a vibrating sample magnetometer (VSM), which revealed that the addition of Cu2+ ions has a significant impact on the magnetic properties of the nanoparticles. The saturation magnetisation (Ms), retentivity (Mr) and coercivity value (Hc) for the Cu-MgFe2O4 sample were found to be 0.18453 emu, 39.584 × 10-3 emu and 139.61 Oe, respectively, while for the Cu-ZnFe2O4 sample, the values were 0.21271 emu, 71.022 × 10-3 emu and 285.91 Oe, respectively. The impact of copper doped nanoferrites on pollutant removal from pharmaceutical wastewater using the membrane Bioreactor (MBR) system has also been accomplished. The results demonstrated the effectiveness of ferrites in reducing concentrations of heavy metals, including lead and cadmium, within acceptable ranges for inland surface water and public sewers. Furthermore, the MBR system with ferrites exhibited efficient removal of fluoride, sulphide and radioactivity, ensuring compliance with the specified standards. Although the study exhibited the potential of ferrites in pollutants removal, further optimization is necessary to achieve complete compliance with water quality standards.

Study Assessment of Soil and Water Quality Conditions on Barren Agricultural Lands in Tropical Regions

Barren land is non-productive land that is difficult to use as a medium for integrated agricultural cultivation. The aim of this research is to determine the profile and feasibility status of land in barren agricultural areas quantitatively. The research method used was descriptive with purposive data collection. Data analysis included SQI and WQI parametric analyses. The research results indicate that the ideal soil parameter is only pH 7.5-7.7, while for water parameters it is pH 8.0-8.1, meeting water quality standards. SQI values range from 0.44 to 0.49 and WQI from 0.45 to 0.57. SQI and WQI values at the research site fall into the poor category, indicating difficulty in converting the land into agricultural use. SQI and WQI show a strong correlation as depicted in the model Y = 4.113 + 0.026 (R2 = 0.789). Correlation tests showed strong correlations in soil between redox potential and soil pH (0.449), and redox potential and organic matter (0.377). Weak correlations were found between cation exchange capacity and soil pH (0.009), and nitrate and total N (0.517). In water, strong correlations were found between water pH and nitrite (0.302) and ammonia (0.529). Additionally, water pH showed weak correlations with carbon dioxide (0.752) and organic matter (0.659). The values of soil and water parameters have an immediate impact on plant growth patterns. Therefore, integrated agricultural cultivation patterns need to be developed. In conclusion, empirically, the condition of barren land indicates poor land use feasibility. The poor profile and biophysical feasibility conditions of barren land are attributed to environmental pollution and runoff from other land areas.

Derivation of environmental quality standards for free cyanide incorporating censored data into species sensitivity distributions

Free cyanide is considered to be the most toxic form of cyanides to aquatic life. Due to its broad range of uses and subsequent potential widespread emissions to surface water, the environmental effects of free cyanide have been extensively researched. Regulatory bodies have proposed water quality standards for free cyanide, but these are regularly debated and implementation has been inconsistent due to monitoring challenges. The aim of the present study was therefore to derive new environmental quality standards (EQS) for free cyanide according to the Water Framework Directive (WFD). Ecotoxicity data from previous derivations and an additional literature search were gathered and individually (re) evaluated on reliability. The pooled acute ecotoxicity dataset consisted of reliable results for 35 species, distributed over 8 taxonomic groups. The pooled chronic ecotoxicity dataset consisted of results for 13 species, distributed over 7 taxonomic groups. WFD criteria for deriving a species sensitivity distribution (SSD) were met, if censored data points were included. Using the R-package ETX 3.0, an SSD including censored data was constructed and acute and chronic HC5 values of 17 and 0.66 μg/L, respectively, were derived. Comparisons were made with alternative SSDs constructed by transforming or discarding the censored data. Applying a default assessment factor (AF) of 10 to the HC5 from the acute SSD resulted in a MAC-EQS of 1.7 μg CN/L for freshwater and marine water. Careful consideration was given to addressing the uncertainty around the chronic HC5 value for the selection of an AF of 3, resulting in an AA-EQS of 0.22 μg CN−/L for freshwater and 0.044 μg CN−/L for marine water by applying an additional AF of 5. It is concluded that the current environmental quality standards for free cyanide are the first to be derived according to the WFD guidance, using only reliable data and including censored values.

Stakeholder contestations of water quality use and management in the Vaal Barrage catchment

The water resources within the lower section of the Upper Vaal catchment, where the Vaal Barrage is situated, are highly utilised and developed, and water quality regulation has become a contested space between resource users and the regulators. The credibility and scientific defensibility of discharge standards in water-use licences (WULs), the relationship between upstream and downstream waste loads, the relationship between flows and water quality standards in WUL, and the water quality components of the resource quality objectives (RQOs) are being contested. This study explores the perceptions and motivations underlying these contestations as a contribution to scientific understanding of water quality management in a highly developed system. Perceived unrealistic RQOs, perceived lack of scientific credibility of the methods for deriving water quality standards in WUL, data inadequacy, as well as poor institutional capacity were identified as the top motivations for contesting applicable regulatory instruments in the catchment. Punitive measures, incentives, and education and awareness-raising were identified as key to accelerating compliance. Overall, this paper contributes to our general understanding of the intricacies of water quality management within a contested space.