DISES Investigating mercury biogeochemical cycling via mixed-methods in complex artisanal gold mining landscapes and implications for community health

DISES 通过混合方法研究复杂手工金矿景观中的汞生物地球化学循环及其对社区健康的影响

• 批准号: 2307870
• 负责人: Heidi Hausermann
• 金额: $ 153.77万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2028-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2307870&HistoricalAwards=false
• 关键词: DISES; Investigating; mercury; biogeochemical; cycling

Human activities lead to increased contamination in both terrestrial and aquatic ecosystems. Contaminants can pose harm to both people and wildlife, with specific harms and exposures dependent on complex socio-ecological factors. This study investigates environmental risk vis-a-vis mercury (Hg) released from artisanal and small-scale gold mining (ASGM) sites. Mercury is a potent neurotoxin used to amalgamate gold in ASGM contexts globally. ASGM has become the leading cause of mercury emissions worldwide and is particularly harmful when burned off gold and emitted as gaseous elemental mercury (GEM). However, little is known about the fate of mercury from ASGM activities, including if and how mercury accumulates in crops, or local knowledge of mercury dangers and exposure routes, all of which contribute to actual and perceived environmental risk. This research asks: (1) What is the local and regional fate of Hg vaporized from ASGM in terrestrial ecosystems? (2) To what extent is Hg accumulating in crops grown near ASGM, and how do landscape and soil characteristics impact crop Hg concentrations? (3) How do local people understand Hg contamination and exposure, and how do spatialities of local knowledge articulate with environmental contamination variability? Results from this research will provide direct benefits related to the goals of the recently ratified International Minamata Convention on Mercury. The research focuses on mercury in Ghanaian ASGM systems with contrasting geology, mining type, climate, and ecosystem. Ghana possesses extensive ASGM activities, which increased dramatically in the last 15 years. To query the research questions, the researchers employ mixed methods including community mapping activities and semi-structured interviews, biogeochemical data collection (passive air samples, bulk deposition, throughfall, litterfall, soil, and crop) and modeling (empirically constrained mass budgets, Lagrangian plume models). As farmers grow crops directly adjacent to ASGM sites, this project models where mercury travels, and how it accumulates in agricultural fields and specific staple crops grown in both communities (e.g. cassava, cocoa yam, plantain). The data generated from this proposal will improve Hg models, allowing for better understanding of environmental risks and contamination dynamics (i.e., Hg use, atmospheric transport, deposition, soil storage, and crop accumulation) associated with localized ASGM activity. Furthermore, this research systematically investigates what soil and landscape features lead to the accumulation of Hg within crops to better understand potential human exposure pathways to Hg beyond occupational exposure and consumption of contaminated fish. At the end of the project, workshops and training will be organized to inform harm reduction practices, including agricultural and mining practices to reduce mercury accumulation in crops, and other local exposures. This research links together concepts from political ecology and landscape ecology in a dynamic bi-directional coupling of socio-environmental systems that determines where and when contaminants deposit and accumulate on the landscape. The concept of “environmental risk landscape” can be further developed to evaluate environmental risk in other socio-environmental contexts, including environmental injustice in the U.S.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

人类活动导致陆地和水生生态系统污染增加。污染物会对人类和野生动物造成伤害，具体危害和暴露程度取决于复杂的社会生态因素。手工和小规模金矿开采 (ASGM) 场所释放的汞是一种强效神经毒素，用于在全球手工和小规模金矿开采中合并黄金，已成为造成这种情况的主要原因。汞在全球范围内排放，当黄金燃烧并以气态元素汞 (GEM) 形式排放时，其危害尤其严重。然而，人们对手工和小规模采金活动中汞的归宿知之甚少，包括汞是否以及如何在农作物中积累，或者当地对汞危险的了解。和暴露途径，所有这些都会造成实际和感知的环境风险。本研究提出以下问题：(1) 陆地生态系统中手工和小规模采金蒸发的汞在当地和区域的命运如何？ (2) 手工和小规模采金附近种植的作物中汞积累的程度如何，景观和土壤特征如何影响作物汞浓度 (3) 当地人如何理解汞污染和暴露，以及当地知识的空间性如何与环境相联系？这项研究的结果将提供与最近批准的国际水俣公约目标相关的直接效益。该研究重点关注加纳手工和小规模采金系统中的汞，并对比加纳的地质、采矿类型、气候和生态系统。拥有广泛的 ASGM 活动，这些活动在过去 15 年中急剧增加。当农民在紧邻手工和小规模采金地点种植农作物时，该项目模拟了汞的移动位置以及汞如何在农田和土壤中积累。该提案生成的数据将改进汞模型，从而更好地了解环境风险和污染动态（即汞的使用、大气传输、沉积、土壤）。此外，本研究系统地调查了哪些土壤和景观特征导致农作物内汞的积累，以更好地了解除职业接触和消费受污染的汞之外的潜在人类接触途径。项目结束时，将组织研讨会和培训，以告知减少危害的做法，包括减少农作物中汞积累的农业和采矿做法，以及其他当地接触的概念。社会环境系统的动态双向耦合，决定污染物在景观上沉积和积累的地点和时间。“环境风险景观”的概念可以进一步发展，以评估其他社会环境背景下的环境风险，包括环境不公正。在美国 该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。