Understanding the transformation of emerging organic contaminants in surface and groundwater

了解地表水和地下水中新兴有机污染物的转化

• 批准号: RGPIN-2021-03309
• 负责人: Ponsin, Violaine
• 金额: $ 1.82万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=765317
• 关键词: Understanding; transformation; emerging; organic; contaminants

Pesticides are detected in surface and groundwater worldwide and pose a major threat to ecosystems and public health. In order to protect the natural world and public health, it is essential to preserve, as much as possible, our water resources. To address this, it is critical to unveil the processes responsible for the transformation of these contaminants in the environment. This will allow us to develop strategies to accelerate the transformation of these chemicals. However, the degradation of contaminants in the environment often appears as a black box since many processes, difficult to disentangle, can occur. A promising approach, giving process-specific information, is compound-specific stable isotope analysis (CSIA). During their transformation, molecules with light isotopes (e.g., 12C) are usually degraded at a different rate than those with heavy isotopes (e.g., 13C), leading to a fractionation in undegraded molecules. This approach is powerful because it can detect specific degradation processes and even quantify them, which is extremely difficult to do with approaches relying only on concentration measurements. The long-term objective of my research is to unveil the transformation pathways driving the degradation of contaminants in water resources. This program focuses on atrazine, metolachlor (herbicides) and their transformation products because of their toxicity to ecosystems and human health. They are also widely applied in Canada and often detected in water resources. Biodegradation is expected to be one of the main pathways for pesticide mitigation in the environment. Abiotic processes can substantially contribute to degradation in surface water and groundwater, but are less studied. The short-term objectives of my research program are: i)To identify and quantify different degradation processes of atrazine and metolachlor in surface water, focusing on photodegradation. ii)To determine the relevance of abiotic transformation of metolachlor in groundwater. Work will be done at different spatial scales, from the laboratory experiments to the field study in Québec lakes and in one aquifer in Ontario. The isotope fractionation of different processes such as photodegradation, abiotic degradation of metolachlor by reduced sulfur species and biodegradation will be determined in controlled conditions before application on the field to reveal the relative contributions of different transformation processes to the overall observed degradation. My research will inform us on the extent of transformation processes of ubiquitous and toxic pesticides in water, the relative contribution of each of these processes to the overall degradation, their spatial and temporal variability, and their limiting factors. This knowledge is critical to predict the long-term impact of these pesticides on water resources, and will help identify promising remediation strategies to protect drinking water and decrease the environmental impact of pesticides.

在全球范围内检测到农药，并对生态系统和公共卫生构成重大威胁。为了保护自然世界和公共卫生，至关重要的是，要尽可能保存我们的水资源。为了解决这个问题，至关重要的是要揭示负责这些污染物在环境中转变的过程。这将使我们能够制定策略来加速这些化学物质的转化。但是，环境中污染物的降解通常是黑匣子，因为许多过程（难以消除）可能会发生。提供特定于过程信息的有前途的方法是复合特异性稳定的同位素分析（CSIA）。在它们的转化过程中，具有光同位素的分子（例如12c）通常以与沉重同位素（例如13C）的降解速率不同，从而导致未基因分子的分数。这种方法是强大的，因为它可以检测特定的降解过程，甚至可以量化它们，这对于仅依靠集中度测量的方法非常困难。我的研究的长期目标是揭示推动水资源中污染物降解的转化途径。该计划的重点是阿特拉津，元甲甲（除草剂）及其转型产品，因为它们对生态系统和人类健康的毒性。它们也被广泛应用于加拿大，经常在水资源中检测到。预计生物降解将是在环境中缓解农药的主要途径之一。非生物过程可能会导致地表水和地下水中的降解，但研究较少。我的研究计划的短期目标是：i）识别和量化地表水中阿特拉津和元甲甲的不同降解过程，重点是光降解。 ii）确定地下水中metolachlor的非生物转化的相关性。从不同的空间尺度进行工作，从实验室实验到魁北克湖的现场研究以及安大略省的一个含水层。不同过程的同位素分馏，例如光降解，减少的硫种类对元硫甲的非生物降解和生物降解，将在对照条件下确定，然后在野外应用以揭示不同转化过程对整体观察到的降解的相对贡献。我的研究将告知我们水中无处不在和有毒农药的转化过程，这些过程中的每一个对整体降解的相对贡献，它们的空间和临时变异性及其限制因素。这些知识对于预测这些农药对水资源的长期影响至关重要，并将有助于确定保护饮用水并减少农药的环境影响的补救策略。