Water quality criteria and ecological risk assessment of lead (Pb) in China considering the total hardness of surface water: A national-scale study

Health impact assessment of the surface water pollution in China

China suffers from severe surface water pollution. Health impact assessment could provide a novel and quantifiable metric for the health burden attributed to surface water pollution. This study establishes a health impact assessment method for surface water pollution based on classic frameworks, integrating the multi-pollutant city water quality index (CWQI), informative epidemiological findings, and benchmark public health information. A relative risk level assignment approach is proposed based on the CWQI, innovatively addressing the challenge in surface water-human exposure risk assessment. A case study assesses the surface water pollution-related health impact in 336 Chinese cities. The results show (1) between 2015 and 2022, total health impact decreased from 3980.42 thousand disability-adjusted life years (DALYs) (95 % Confidence Interval: 3242.67-4339.29) to 3260.10 thousand DALYs (95 % CI: 2475.88-3641.35), measured by total cancer. (2) The annual average health impacts of oesophageal, stomach, colorectal, gallbladder, and pancreatic cancers added up to 2621.20 thousand DALYs (95 % CI: 2095.58-3091.10), revealing the significant health impact of surface water pollution on digestive cancer. (3) In 2022, health impacts in the Beijing-Tianjin-Hebei and surroundings, the Yangtze River Delta, and the middle reaches of the Yangtze River added up to 1893.06 thousand DALYs (95 % CI: 1471.82-2097.88), showing a regional aggregating trend. (4) Surface water pollution control has been the primary driving factor to health impact improvement, contributing -3.49 % to the health impact change from 2015 to 2022. It is the first city-level health impact map for China's surface water pollution. The methods and findings will support the water management policymaking in China and other countries suffering from water pollution.

Comprehensive assessment of exposure and environmental risk of potentially toxic elements in surface water and sediment across China: A synthesis study

China faces a serious challenge with water pollution posed by potentially toxic elements (PTEs). Comprehensive and reliable environmental risk assessment is paramount for precise pollution prevention and control. Previous studies generally focused on a single environmental compartment within small regions, and the uncertainty in risk calculation is not fully considered. This study revealed the current exposure status of 11 PTEs in surface water and sediment across China using previously reported concentration data in 301 well-screened articles. Ecological and human health risks were evaluated and the uncertainty related to calculation parameters and exposure dataset were quantified. PTEs of high concern were further identified. Results showed Mn and Zn had the highest concentration levels, while Hg and Cd had the lowest concentrations in both surface water and sediment. Risk assessment of individual PTE showed that high-risk PTEs varied by risk receptors and environmental compartments. Nationwide, the probability of aquatic organisms being affected by Mn, Zn, Cu, and As in surface water exceeded 10 %. In sediment, Cd and Hg exhibited high and considerable risk, respectively. As was identified as the major PTE threatening human health as its carcinogenic risk was 1.45 × 10-4 through direct ingestion. Combined risk assessment showed the PTE mixture in surface water and sediment posed medium and high ecological risk with the risk quotient and potential ecological risk index of 1.76 and 558.36, respectively. Adverse health effects through incidental ingestion and dermal contact during swimming were negligible. This study provides a nationwide risk assessment of PTEs in China's aquatic environment and the robustness is verified, which can serve as a practical basis for policymakers to guide the early warning and precise management of water pollution.

Profound regional disparities shaping the ecological risk in surface waters: A case study on cadmium across China

The scientific advancement of water quality criteria (WQC) stands as one of the paramount challenges in ensuring the security of aquatic ecosystem. The region-dependent species distribution and water quality characteristics would impact the toxicity of pollutant, which would further affect the derivation of WQC across regions. Presently, however, numerous countries adhere to singular WQC values. The "One-size-fits-all" WQC value for a given pollutant may lead to either "over-protection" or "under-protection" of organisms in specific region. In this study, we used cadmium(Cd) pollution in surface waters of China as a case study to shed light on this issue. This study evaluated critical water quality parameters and species distribution characteristics to modify WQC for Cd across distinct regions, thus unveiling the geographical variations in ecological risk for Cd throughout China. Notably, regional disparities in ecological risk emerged a substantial correlation with water hardness, while species-related distinctions magnified these regional variations. After considering the aforementioned factors, the variation in long-term WQC among different areas reached 84-fold, while the divergence in risk quotient extended to 280-fold. This study delineated zones of both heightened and diminished ecological susceptibility of Cd, thereby establishing a foundation for regionally differentiated management strategies.

Fabrication of gelatin-incorporated nanoporous chitosan-based membranes for potential water desalination applications

Membrane technology has extensively been used in diverse phenomena such as separation, purification and controlled transportation. Herein, gelatin-incorporated porous chitosan membranes have been prepared using the sol-gel approach for potential water desalination applications. The porogens of poly(ethylene glycol) and Triton X-100 were employed for the mentioned purpose. The prepared porous membranes have been characterized for surface chemical, structural, thermal, mechanical and functional attributes using appropriate analytical approaches. Electron microscopy expressed porous surface morphologies of the resultant films with an average pore size of 14.5 nm. The infrared analysis demonstrated a successful crosslinking of the precursors in the resulting membranes via maleic anhydride. Differential scanning calorimetry analysis disclosed acceptable thermal stability of the test membranes, workable above ambient temperatures. The membrane expressed a water contact of 68.59°, which indicated moderate hydrophilicity, thus allowing controlled transport of the aqueous media. The resultant gelatin/chitosan porous membrane exhibited a porosity of 98 % against kerosene oil. In contrast, the flowability of 7.14 (ethanol), 5.00 (distilled water) and 0.53 (ethylene glycol) mL/min has been recorded against the mentioned liquids. The membrane efficiently purified the local canal water to permissible limits. Such membranes have been qualified for potential applications in water purification systems.

Fluorescence biosensor for ultrasensitive detection of the available lead based on target biorecognition-induced DNA cyclic assembly

A fluorescence biosensor was developed for the ultrasensitive detection of the available lead in soil samples by coupling with DNAzyme and hairpin DNA cyclic assembly. The biorecognition between lead and 8-17 DNAzyme will cleave the substrate strands (DNA2) and release the trigger DNA (T), which can be used to initiate the DNA assembly reactions among the hairpins (H1, H2, and H3). The formed Y-shaped sensing scaffold (H1-H2-H3) contains active Mg2+-DNAyzmes at three directions. In the presence of Mg2+, the BHQ and FAM modified H4 will be cleaved by the Mg2+-DNAyzme to generate a high fluorescence signal for lead monitoring. The linear range of the fluorescence biosensor is from 1 pM to 100 nM and the detection limit is 0.2 pM. The biosensor also exhibited high selectivity and the nontarget competing heavy metals did not interfere with the detection results. Compare with the traditional method (DTPA+ICP-MS) for the available lead detection, the relative error (Re) is in the range from -8.3 % to 9.5 %. The results indicated that our constructed fluorescence biosensor is robust, accurate, and reliable, and can be applied directly to the detection of the available lead in soil samples without complex extraction steps.

Advancements, Challenges, and Future Directions in Aquatic Life Criteria Research in China

Aquatic life criteria (ALC) serve as the scientific foundation for establishing water quality standards, and in China, significant strides have been made in the development of freshwater ALC. This comprehensive review traces the evolution of China's WQC, focusing on the methodological advancements and challenges in priority pollutants selection, test organism screening, and standardized ecotoxicity testing protocols. It also provides a critical evaluation of quality assurance measures, data validation techniques, and minimum data requirements essential for ALC assessments. The paper highlights China's technical guidelines for deriving ALC, and reviews the published values for typical pollutants, assessing their impact on environmental quality standards. Emerging trends and future research avenues are discussed, including the incorporation of molecular toxicology data and the development of predictive models for pollutant toxicity. The review concludes by advocating for a tiered WQC system that accommodates China's diverse ecological regions, thereby offering a robust scientific basis for enhanced water quality management.