Graduate Institute of Environmental Engineering, National Taiwan University, No.71, Chou-Shan Road, Taipei city, 106, Taiwan.
Green Energy and Environment Research Laboratory, Industrial Technology Research Institute, No.195, Chung Hsing Road, Section 4, Chu Tung, Hsinchu county, 310, Taiwan.
Environ Sci Pollut Res Int. 2019 Jun;26(17):17762-17773. doi: 10.1007/s11356-019-05176-0. Epub 2019 Apr 27.
In Taiwan, because of the co-use of some irrigation and drainage canals, a portion of industrial wastewater was directly discharged into irrigation canals or even flowed into rivers or wetlands, causing the heavy metal pollution in waters and sediments. Mercury (Hg) contamination in rivers, irrigation canals, and wetlands has been found in Taiwan, but a thorough investigation on the distribution of Hg and methylmercury (MeHg) in these waters and sediments, which may be present in a greater level with elevating total Hg (THg) concentration and markedly impact human health, is still lacking. In this study, surface waters and surface sediments were sampled from five major rivers, two irrigation canals, two reservoirs, and one wetland in Taiwan, and their THg and MeHg concentrations were quantified. Additionally, statistical analysis was carried out to understand the relationship between sediment properties and MeHg levels. The results showed that irrigation canal sediments were relatively more polluted by Hg and the THg concentrations of some sampling points exceeded the upper limit (i.e., 0.87 mg kg) of sediment quality index (SQI) for THg promulgated by Taiwan Environmental Protection Administration, which may be attributed to the co-use of irrigation and drainage canals. Furthermore, the MeHg concentration in irrigation canal sediments was the highest; rivers came in second followed by wetlands. In addition, the Siangshan Wetland was analyzed to have the greatest THg and MeHg concentrations in its surface water. Linear regression analysis also indicated that total organic carbon and clay content substantially affected the MeHg production in sediments.
在台湾，由于一些灌溉和排水渠的共同使用，一部分工业废水被直接排放到灌溉渠中，甚至流入河流或湿地，导致水域和沉积物中的重金属污染。在台湾已经发现河流、灌溉渠和湿地中的汞（Hg）污染，但对于这些水域和沉积物中 Hg 和甲基汞（MeHg）的分布情况，以及随着总汞（THg）浓度的升高可能存在更高水平的 Hg 和 MeHg，且对人类健康有显著影响的情况，仍缺乏全面的调查。在这项研究中，从台湾的五条主要河流、两条灌溉渠、两个水库和一个湿地采集了地表水和表层沉积物样本，并对其 THg 和 MeHg 浓度进行了定量分析。此外，还进行了统计分析，以了解沉积物特性与 MeHg 水平之间的关系。结果表明，灌溉渠沉积物受到 Hg 的污染相对较为严重，部分采样点的 THg 浓度超过了台湾环保署发布的 THg 沉积物质量指数（SQI）上限（即 0.87mg/kg），这可能是由于灌溉和排水渠的共同使用造成的。此外，灌溉渠沉积物中的 MeHg 浓度最高，其次是河流，然后是湿地。此外，对相思山湿地的分析表明，其表层水中的 THg 和 MeHg 浓度最高。线性回归分析还表明，总有机碳和粘土含量对沉积物中 MeHg 的产生有很大影响。
