In this study, the effects of As-contaminated groundwater by various minerals in the soil were evaluated. The influence of As on microbial inhibition and activities influenced by soil minerals such as clay minerals (bentonite and kaolinite) and iron oxides (hematite, goethite, and magnetite) were investigated. The method used to evaluate the effects of soil minerals on As-contaminated groundwater was to indirectly measure microbial activity by two methods, measurement of optical density (OD) and fluorescein diacetate (FDA) hydrolysis. This study used Pseudomonas jinjuensis, a microorganism commonly found in soil and groundwater. The measurement of OD is a simple and quick method of identifying the growth of microorganisms, affecting turbidity up to dead cells after dead phase, making it difficult to identify actual living microorganisms; thus, it was inappropriate for toxicity assessment. However, the use of FDA is able to measure the bioavailability of microorganisms due to actual As contamination by the luminescence of the fluorescein caused by the enzymes of living microbes. The bentonite and hematite showed that promoting bacteria activity of 140.5% and 7.9%, respectively, and reducing the negative impact from As to bacteria, constantly, magnetite had a negative impact on bacteria activity. These results indicate that the clay minerals and iron oxides influenced the bioavailability of As in groundwater. Also, surface area and cation exchange capacity (CEC) of clay minerals and iron oxides were important parameters on the bioavailability of As.

中文翻译：

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粘土和氧化铁对生物有效性砷的吸附作用提高土壤微生物活性

在这项研究中，评估了土壤中各种矿物对被砷污染的地下水的影响。研究了砷对微生物抑制的影响以及土壤矿物（如粘土矿物（膨润土和高岭石）和氧化铁（赤铁矿，针铁矿和磁铁矿）的影响。评估土壤矿物质对被As污染的地下水的影响的方法是通过两种方法间接测量微生物活性，即光密度（OD）和荧光素二乙酸酯（FDA）水解测量。本研究使用了金菊假单胞菌，一种常见于土壤和地下水中的微生物。OD的测定是一种简单快速的鉴定微生物生长的方法，它会影响死相后直至死细胞的浊度，从而难以鉴定实际的活微生物。因此，不适合进行毒性评估。但是，FDA的使用能够测量由于活微生物酶引起的荧光素发光导致的实际As污染而导致的微生物生物利用度。膨润土和赤铁矿显示出分别提高细菌活性140.5％和7.9％，并减少了砷对细菌的负面影响，不断地，磁铁矿对细菌活性产生负面影响。这些结果表明粘土矿物和氧化铁影响了地下水中砷的生物利用度。也，