Arsenic (As), the silent poison, is a widespread environmental pollutant which finds its way into drinking water supplies from natural or man-made sources and affects over 200 million people worldwide, including in Pakistan. It has been demonstrated that As causes serious health complications as well as social and economic losses. A quick, cost-effective, and simple method for efficiently filtering As from drinking water is urgently needed. The present study evaluates the ability of chemical treatment solutions to activate the sorption capacity of biochar derived from cotton stalks. The surface characteristics of CSB (cotton stalk biochar), HN-CSB (treated with nitric acid: HNO₃), and Na-CSB (treated with sodium hydroxide: NaOH) were investigated for their As sorption capacities and efficiency in removing As from contaminated drinking water. The chemical modification of biochar significantly increased the surface area and pore volume of CSB, with a maximum observed in HN-CSB (three times higher than CSB). Fourier-transform infrared spectroscopy (FTIR) analysis revealed several functional groups (OH⁻, −COOH, C=O, N-H) on CSB, though the chemical modification of biochar creates new functional groups on its surface. Results showed that the maximum sorption capacity of CSB was (q = 90 µg g⁻¹), of Na-CSB was (q = 124 µg g⁻¹) and of HN-CSB was (q = 140 µg g⁻¹) at an initial As concentration of 200 µg L⁻¹, an adsorbent dose of 1 g L⁻¹, with 4 h of contact time, a pH of 6 and a temperature of 25 ʰC. However, As removal was found to be 45–88% for CSB, 62–94% for Na-CSB and 67–95% for HN-CSB across all As concentrations. An isotherm model showed that As sorption results were best fitted to the Langmuir isotherm model in the case of CSB (Q_max = 103 µg g⁻¹, R² = 0.993), Na-CSB (Q_max = 151 µg g⁻¹, R² = 0.991), and HN-CSB (Q_max = 157 µg g⁻¹, R² = 0.949). The development of the largest surface area, a porous structure, and new functional groups on the surface of HN-CSB proved to be an effective treatment for As removal from contaminated drinking water. Both HN-CSB and Na-CSB are clearly cost-effective adsorbents under laboratory conditions, but HN-CSB is cheaper and more efficient in As removal than Na-CSB, allowing it to be used as a powerful and promising adsorbent for the removal of pollutants like Arsenic from aqueous solution.

Arsenic (As) is a global public health and environmental problem because of its non-degradable and toxic nature. This study was carried out to assess the As contamination and potential health risk through water intake in rural and urban areas. Water samples were collected from urban and rural areas of Kahror Pacca, Punjab, Pakistan, and then, analyzed for As concentration. The concentrations of As in water samples were 1.62 − 35.28 and 3.23 − 45.62 μg/L for the rural and urban areas, respectively. The spatial distribution of As-rich shallow groundwater specifies their direct contamination through anthropogenic influence and agricultural practices. The chronic risk exposure was evaluated based on the determined As through hazard quotient, average daily dose, and cancer risk. Results disclosed that hazard quotient values were > 1 in studied drinking water samples. The cancer risk due to As consumption surpassed the threshold limits defined by the United States environmental protection agency (1.0E-04 to 1.0E06). Statistical analyses, including principal component analyses and Pearson correlation, suggested that As contamination in drinking water was imputed to both geogenic and anthropogenic reasons. It is revealed that intake of As contaminated water might result in various cancer problems to the community in the future.

Investigations of microbial communities over arsenic-polluted soils in an alpine stream are vital to collect pieces of evidence for their in situ-mediated bioremediation. It is the first time that microbial community activities are described in arsenic-polluted soils due to natural and anthropogenic sources along the alpine stream. Greater than 40 phyla from domain bacteria the 16S rRNA Illumina sequencing amplicons are exposed. In overall samples, Unweighted Pair Group Method with Arithmetic Mean (UPGMA) states that the most dominant phyla were Proteobacteria, Cyanobacteria, and Actinobacteria. Our result described that canonical correspondence analysis was used to elaborate more geochemical factors including arsenic, sulfate, total organic carbon, redox potential, and pH influence on the distribution of microbial groups in studies soil samples. Furthermore, Spearman’s rank correlation demonstrates a positive correlation between several specific taxonomic groups, refers to the phylotypes’ possible role in arsenic biogeochemical cycling. The present research could link the knowledge gap and facilitate our understanding for the bioremediation of arsenic at contaminated sites.

Plant growth stimulating bacteria are very effective in immobilization of metals and reducing their translocation in plants through precipitation, and adsorption. A pot experiment was conducted to investigate the effectiveness of chitosan- and hematite-modified biochar and bacterial inoculations on the immobilization of nickel (Ni) in polluted soil under wheat cultivation. Application of modified biochars and inoculation with Pseudomonas putida significantly increased both wheat root and shoot dry matter yields but decreased Ni phytoextraction efficiency. The Ni concentration, translocation factor and uptake in wheat shoot and root significantly decreased the application of either modified or unmodified biochars. Bacterial inoculation significantly decreased mean translocation factor and also root and shoot concentration and the uptake Ni in the shoot. Chitosan-modified biochar was the most influential treatment in decreasing Ni uptake by wheat followed by P. putida inoculation treatment. The results demonstrated positive effects of chitosan modified biochar and inoculation with P. putida in increasing dry matter yield and decreasing Ni uptake in wheat grown on Ni-contaminated soil. According to the results of present study, modified biochars application and bacterial inoculation are influential treatments which prevent Ni toxicity probably.

This study assesses the ecological status of alpine lotic ecosystems in Khunjerab National Park, Pakistan, situated at approximately 4000 m in the Karakoram Range along the Pakistan–China border. An integrative approach was employed, evaluating alpine stream ecosystems through benthic macroinvertebrate indices in conjunction with physicochemical habitat parameters. Samples were gathered using kick nets and hand-picking at seventeen randomly selected sites in early spring and summer. The study recorded 710 summer taxa from 41 families and seven orders, and 1250 early spring taxa from 30 families and six orders. The abundance of macroinvertebrates increased in early spring, while taxonomic diversity increased during the summer. Statistical tests revealed a strong relationship between water quality conditions and biological features. The biotic index reached its peak in early spring, while diversity indices peaked in summer when Ephemeroptera dominated. Due to the macroinvertebrate source in early spring, the majority of EPT taxa were abundant at all alpine stream sites during early spring, except for upstream sites in summer. The indices from the biotic metric evaluation revealed low levels of natural environmental disturbance caused by humans. This research is significant in terms of natural resource conservation and health assessment based on the benthic fauna community structure in alpine streams.

Water is very important to maintaining life on earth. Fluoride and Arsenic pollution in groundwater is an emerging issue in the world. Atomic absorption spectrometry was used to measure total arsenic, while ion chromatography was used to determine fluoride. The present study was conducted for the health risk assessment of fluoride and arsenic in groundwater around brick kilns. 58 samples of groundwater were collected from district Vehari Punjab and were analyzed for arsenic concentration ranges from 0.330 to 11.120 µg/L, higher than the WHO recommended permissible level of arsenic in drinking water (10 µg/L). The mean value of fluoride in the water supply for drinking is 2.599 mg/L as its concentration ranges are 0.680 to 9.690 mg/L respectively. All the values of fluoride in drinking water were higher than the permissible limit according to WHO standard 1.5 mg/L. The spatial distribution of arsenic and fluoride in groundwater indicates their direct contamination with rock weathering, coal burning, and the use of cheap fuel in brick kilns. The estimated average dose (ADD), hazards quotient (HQ), as well as cancer risk (CR), were computed using statistical formulae to determine the health risks of arsenic and fluoride. The hazard quotient (HQ) values of As and F⁻ in this research area were higher protection and safe limits (HQ > 1), having health risks to the people in this region, caused by brick kilns. Statistical parameters correlation and cluster analysis were used to determining possible contaminant sources in the study area.