DEVELOPMENT OF IN-SITU MERCURY REMEDIATION APPROACHES BASED ON METHYLMERCURY BIOA

说明（由申请方提供）：拟议研究的目标是推动汞的原位补救工具的开发。汞污染沉积物和土壤的补救办法很少，缺少覆盖和疏浚。就地补救尚未广泛用于汞，但在成本和保护生态系统服务方面具有显著优势，特别是对于低/中度污染的大面积地区。最近的两项重大进展增加了制定有效的汞就地补救办法的机会。首先，最近的实验室和现场试验表明，在原位活化卡隆修正案，适用于作为一个薄层未受干扰的沉积物或土壤，可以显着减少甲基汞接触污染的网站。其次，今年早些时候鉴定出负责微生物汞甲基化的基因对（hgcAB）将首次确定环境中汞甲基化微生物的分布和活性。含有这些基因的生物似乎相对罕见，它们在自然界中的分布仍然未知。这有可能大大改进甲基汞生产模型。这项研究将利用这两个发展，以及其他一些新的工具，以更好地了解对甲基汞生产和生物利用度的控制，制定就地补救办法，并确定可能使这些技术的网站适当的地球化学特征。利用这一新的信息，我们的目标是开发一个经验模型的影响因素，汞和甲基汞的生物利用度在污染地区：1）确定的特点，使汞污染的网站适合在原位吸附剂修复，和2）设计吸附剂修正/薄封顶战略，降低甲基汞的生物利用度。主要的研究地点将是新泽西州贝里溪的盐沼，在那里我们刚刚开始了现场试验，使用活性炭进行吸附剂原位修复。将在贝里溪沼泽进行额外的实地试验，以评估更广泛的黑碳的相对功效。除了在贝里溪进行的密集工作外，还将利用其他汞污染地点的沉积物和土壤进行实验室微观研究。这种方法将用于评估各种黑碳在更广泛的地球化学和现场条件下的功效。

DESCRIPTION (provided by applicant): The goal of the proposed study is to advance the development of in situ remediation tools for mercury. There are few available remediation options for Hg contaminated sediments and soils, short of capping and dredging. In situ remediation has not been widely used for mercury, but offers significant advantages in cost and in preservation of ecosystem services especially for large areas with low/moderate levels of contamination. Two recent major advances improve the chances for development of effective in situ remediation options for Hg. First, recent lab and field trials show that in situ activated caron amendments, applied as a thin layer to undisturbed sediments or soils, can significantly reduce MeHg exposure from contaminated sites. Second, the identification of the gene pair responsible for microbial Hg methylation earlier this year (hgcAB) will allow the distribution and activity of Hg- methylating microorganisms in the environment to be established for the first time. Organisms that contain these genes appear to be relatively rare, and their distribution in nature remains unknown. This has the potential to significantly improve models of MeHg production. This research study will take advantage of both of these developments, and several other novel tools, to develop a better understanding of the controls on MeHg production and bioavailability, to develop in situ remediation approaches, and to identify biogeochemical characteristics that may make sites appropriate for these technologies. Using this new information, our goal is to develop an empirical model of the factors influencing Hg and MeHg bioavailability in contaminated areas to: 1) identify characteristics that make Hg- contaminated sites suitable for in situ sorbent remediation, and 2) design sorbent amendment/thin capping strategies that reduce MeHg bioavailability. The main study site will be a salt marsh in Berry's Creek, NJ, where we have just begun a field trial of in situ sorbent remediation using activated carbon. Additional field trials in the Berry's Creek marsh will be done to evaluate the relative efficacy o a wider range of black carbons. This intensive work in Berry's Creek will be supplemented with laboratory microcosm studies using sediments and soils from other Hg-contaminated sites. This approach will be used to evaluate the efficacy of a variety of black carbons across a wider range of biogeochemical and site conditions.