Water quality and health risk assessment of the water bodies in the Yamdrok-tso basin, southern Tibetan Plateau

Suitability of the Himalayan water quality for domestic and irrigation use: A systematic review and meta-analysis

The Himalayan region, a critical freshwater source for South Asia, faces increasing anthropogenic pressures, which impact water quality for domestic and agricultural uses. This study bridges a significant knowledge gap by conducting a systematic review and meta-analysis of 274 studies (2003-24) to evaluate heavy metals (HMs) contamination levels, health risk assessments, and hydrochemical parameters and to assess suitability for both domestic and irrigation use. The analysis revealed that HMs levels are higher than the WHO standards in India and Pakistan. Although the pollution indices improved over time, with the Degree of Contamination (DOC) decreasing from 138.02 (2003-13) to 49.86 (2014-24) and the Pollution Load Index (PLI) decreasing from 2.68 to 0.29, the water quality of the Himalayas is still considered unsafe for domestic use. Furthermore, water pH, Electrical Conductivity (EC), and major cations/anions were observed within acceptable limits. However, the Total Hardness (TH), Potential Salinity (PS), and Residual Sodium Carbonate (RSC) values were relatively high. In India, the Corrosivity Ratio (CR) level is higher than the allowable limits. Overall, water quality needs improvement in this region, as evidenced by TH, PS, and RSC values higher than allowable limits over the last two decades. This study establishes trends over two decades, emphasizing notable improvements but significant non-carcinogenic and carcinogenic health risks from heavy metals, especially in children, necessitating continued monitoring and stricter regulations with robust water management strategies. The study also aligns with the United Nations Sustainable Development Goals (SDGs), particularly SDG-6, SDG-3, and SDG-12.

Ostracod-based transfer function shifting to a broad prospect in palaeolimnology and palaeoclimate

The ostracod-based transfer function is a common method in palaeolimnology and palaeoclimate research, serving as an interpreter from fossil record to palaeoenvironment history. However, migration application of the transfer function remains challenging, and it is characterized by the use of the threshold of the transfer function and restriction of the understanding of palaeolimnology and palaeoclimate. Here, we constructed transfer functions for water salinity, alkalinity, and Ca conditions employing ecological information about four key species in the Yamdrok-tso basin. The prediction power of the transfer functions and their migration application in the Pumoyum Co were evaluated. The results show that the prediction power of the transfer functions was maintained according to the statistical indices of the cross-validation (R2, root mean square error, Rjack2, and root mean square error of prediction). The palaeoenvironment records constructed for the Pumoyum Co using transfer functions are in good agreement with the lake depth, mean grain size, ostracod diversity, and stalagmite δ18O records, indicating the considerable applicability of the transfer function in different ecosystems. Our study provides fresh insights for the application of transfer functions to palaeoenvironment reconstruction, enhancing the comprehension of palaeolimnology and palaeoclimate.

Preeminent Terminator of Oxygen Free Radicals─Mineralized Reduced Water

Drinking water is an essential daily intake to hydrate the body. It is conceivable that water, when endowed with antioxidant properties, will be the most natural radical terminator surpassing conventional pill-based or food-derived antioxidants. However, current end-of-pipe purification of municipal water generally depletes minerals pivotal for antioxidant potency. To surmount this dilemma, we assemble a multistage and multifunctional water treatment system using various filter materials that dislodge contaminants, mineralize water and impart reductive attributes. The mineralized reduced water (MRW) generated by this system possesses an ideal antioxidant water quality with weak alkalinity, negative oxidation-reduction potential and rich minerals including calcium, magnesium, zinc and silicon. This water decreases oxidative products in vivo via counteracting reactive oxygen species and activating the endogenous antioxidant system governed by nuclear factor erythroid 2-related factor 2. Moreover, long-term intake of MRW effectively retards xenografted tumor growth without any discernible hematologic and organic toxicity. These findings portend enormous promise for MRW in the prevention and treatment of oxidative stress-related maladies and even antiaging.

Spatio-temporal variation of groundwater pollution in urban wetlands and management strategies for zoning

Groundwater is an important resource to maintain the sustainable development of urban wetlands. The Jixi National Wetland Park (JNWP) was studied to realize the refined prevention and control of groundwater. The self-organizing map-K-means algorithm (SOM-KM), improved water quality index (IWQI), health risk assessment model and forward model were used comprehensively to evaluate the groundwater status and solute sources in different periods. The results showed that the groundwater chemical type in most areas was the HCO₃-Ca type. Groundwater chemistry data from different periods were clustered into five groups. Groups 1 and 5 are affected by agricultural and industrial activities, respectively. The IWQI value in the normal period was higher in most areas due to the influence of spring ploughing. The east side of the JNWP was disturbed by human activities, and the quality of drinking water continued to deteriorate from the wet period to the dry period. 64.29% of the monitoring points showed good irrigation suitability. The health risk assessment model showed that the health risk was the largest in the dry period and the smallest in the wet period. The main factors causing health risks in the wet period and other periods were NO₃^- and F^-, respectively. The overall cancer risk was within acceptable limits. The forward model and ion ratio analysis showed that the weathering of carbonate rocks was the main factor affecting the evolution of groundwater chemistry, accounting for 67.16%. The high-risk areas of pollution were mainly concentrated in the east of the JNWP. K⁺ and Cl^- were the key monitoring ions in the risk-free zone and potential risk zone, respectively. The research can be used to help decision-makers carry out fine zoning control of groundwater.

Copper-mediated shifts in transcriptomic responses of intestines in Bufo gargarizans tadpoles to lead stress

The differential transcriptomic responses of intestines in Bufo gargarizans tadpoles to Pb alone or in the presence of Cu were evaluated. Tadpoles were exposed to 30 μg/L Pb individually and in combination with Cu at 16 or 64 μg/L from Gosner stage (Gs) 26 to Gs 38. After de novo assembly, 105,107 unigenes were generated. Compared to the control group, 7387, 6937, and 11139 differentially expressed genes (DEGs) were identified in the treatment of Pb + Cu0, Pb + Cu16, and Pb + Cu64, respectively. In addition, functional annotation and enrichment analysis of DEGs revealed substantial transcriptional reprogramming of diverse molecular and biological pathways were induced in all heavy metal treatments. The relative expression levels of genes associated with intestinal epithelial barrier and bile acids (BAs) metabolism, such as mucin2, claudin5, ZO-1, Asbt, and Ost-β, were validated by qPCR. This study demonstrated that Pb exposure induced transcriptional responses in tadpoles, and the responses could be modulated by Cu.