Dynamic interactions between hydrogeological and exposure parameters in daily dose prediction under uncertainty and temporal variability

Research on drinking-groundwater source safety management based on numerical simulation

A drinking-groundwater source protection technology system based on a three-dimensional finite-difference groundwater model was constructed and applied to the safe management of drinking groundwater in the first terrace of Fujiang River. In the study area, the main type of groundwater is the quaternary systemic alluvial deposit loose rock pore water and the aquifer thickness varies between 20 and 35 m. Groundwater is the main source of water and is used for various purposes through two exploitation wells. The water volumes of 1# exploitation well (1#) and 2# exploitation well (2#) are 10,000 m³/day and 5000 m³/day, respectively. An analysis of 22 indicators from 11 groundwater samples showed that a higher concentration of chemical-oxygen-demand (COD_Mn) and ammonia–nitrogen (NH₃–N), and they had a high correlation with most of the other water-quality factors. Therefore, COD_Mn and NH₃–N were selected as indicator factors for model calibration and prediction. Twenty-two hydraulic head observation wells were used for flow-model calibration. The flow model indicated that a drop funnel formed with a maximum depth of 12 m, and the particle-capture zone in the original downstream direction of the south side extended to 1100 m because of groundwater exploitation. The solute-transport model showed that industrial pollution sources were the main factors that led to a deterioration of water quality. To analyze the necessity and effectiveness of remediation measures for the safety of drinking-water sources, two scenarios were considered to predict the concentration of NH₃-N and COD_Mn in groundwater exploitation wells over 20 years. Scenario I, which considered that current conditions were maintained, predicted that the NH₃-N would exceed the drinking-water quality standard of 0.5 mg/L after 16 years. Scenario II, in which industrial sewage treatment plants were installed outside the particle-trapped zone of the exploitation wells and strict anti-seepage measures were implemented, predicted that the peak concentrations of NH₃-N and COD_Mn in the exploitation wells would be 0.26 mg/L and 1.33 mg/L, respectively, after 3 years of model operation. This study provides a theoretical basis for drinking-groundwater source protection that can be applied to safety management practices.

Multi-dimensional dynamic fuzzy monitoring model for the effect of water pollution treatment

The rapid development of the economy in China resulted in increasingly serious water pollution problem. A lot of water pollution treatment projects have been launched to improve the water environment quality. Water pollution treatment is a complex and long-term task. Considering the concept of water pollution with fuzziness and the factors affecting the effect of water pollution treatment (EWPT), this study constructs a multi-dimensional dynamic fuzzy comprehensive monitoring model. The model considers the vague boundaries in the representation of water pollution and various factors affecting the treatment effect, such as monitoring time, monitoring index, and monitoring location. In detail, firstly, existing methods for evaluating the EWPT are analyzed and reviewed. Then a multi-dimensional dynamic model is developed for monitoring the EWPT. Finally, the Yueya Lake of Henan Province in China is taken as an example to demonstrate the effectiveness and practicability of the proposed method. From the analysis of the results, to maintain the cleanliness of the water, efforts should still be made to eliminate and completely block the pollutants on the shore in order to fundamentally solve the problem.

Emergency control system based on the analytical hierarchy process and coordinated development degree model for sudden water pollution accidents in the Middle Route of the South-to-North Water Transfer Project in China

Water transfer projects are important for realizing reasonable allocation of water resources, but once a water pollution accident occurs during such a project, the water environment is exposed to enormous risks. Therefore, it is critical to determine an appropriate emergency control system (ECS) for sudden water pollution accidents that occur in water transfer projects. In this study, the analytical hierarchy process (AHP) integrated with the coordinated development degree model (CDDM) was used to develop the ECS. This ECS was developed into two parts, including the emergency risk assessment and the emergency control. Feasible emergency control targets and control technology were also proposed for different sudden water pollution accidents. A demonstrative project was conducted in the Fangshui to Puyang channel, which is part of the Beijing-Shijiazhuang Emergency Water Supply Project (BSP) in the Middle Route of the South-to-North Water Transfer Project (MR-SNWTP) in China. However, we could not use an actual toxic soluble pollutant to validate our ECS, so we performed the experiment with sucrose to test the ECS based on its concentration variation. The relative error of peak sucrose concentration was less than 20 %.

Integrated frameworks for assessing and managing health risks in the context of managed aquifer recharge with river water

Integrated assessment and management of water resources for the supply of potable water is increasingly important in light of projected water scarcity in many parts of the world. This article develops frameworks for regional-level waterborne human health risk assessment of chemical and microbiological contamination to aid water management, incorporating economic aspects of health risks. Managed aquifer recharge with surface water from a river in Southern Finland is used as an illustrative case. With a starting point in watershed governance, stakeholder concerns, and value-at-risk concepts, we merge common methods for integrative health risk analysis of contaminants to describe risks and impacts dynamically and broadly. This involves structuring analyses along the risk chain: sources-releases-environmental transport and fate-exposures-health effects-socio-economic impacts-management responses. Risks attributed to contaminants are embedded in other risks, such as contaminants from other sources, and related to benefits from improved water quality. A set of models along this risk chain in the case is presented. Fundamental issues in the assessment are identified, including 1) framing of risks, scenarios, and choices; 2) interaction of models and empirical information; 3) time dimension; 4) distributions of risks and benefits; and 5) uncertainties about risks and controls. We find that all these combine objective and subjective aspects, and involve value judgments and policy choices. We conclude with proposals for overcoming conceptual and functional divides and lock-ins to improve modeling, assessment, and management of complex water supply schemes, especially by reflective solution-oriented interdisciplinary and multi-actor deliberation.