Natural wetlands have been recognized as a natural reactor for degradation and elimination of environmental pollutants. The Upo Wetland, the largest inland wetland in Korea, is mainly surrounded by agricultural lands and it is susceptible to contamination from excess nutrient loads and synthetic organic contaminants (SOCs) (e.g., pesticides). The aim of this study was to identify major SOCs in the wetland and evaluate their degradation. We used high resolution mass spectrometry (HRMS) with a two-step analysis approach (i.e., 1^st analysis for target measurement along with suspect and non-target screening (SNTS) and 2^nd analysis for complimentary suspect screening) to identify and quantify the transformation products (TPs) of the identified parent SOCs. Quantitative analysis of 30 targets, mainly including pesticides, showed that fungicides were the major SOCs detected in the wetland, accounting for about 50% of the composition ratio of the total SOCs quantified. Orysastrobin occurred at the highest mean concentration (>700 ng/L), followed by two other fungicides, carbendazim and tricyclazole. The first analysis (SNTS) tentatively identified 39 TPs (30 by suspect, 9 by non-target screening) of 14 parent pesticides. Additionally, the second analysis (complimentary suspect screening) identified 9 more TPs. Among the 48 total TPs identified, 7 were confirmed with reference standards. The identification of the remaining TPs had a high confidence level (e.g., level 2 or 3). Regarding transport though the wetland, most TPs showed greater peak area ratios (i.e., the relative portion of chromatographic area of the TPs to the parent compound) at the outlet point of the wetland compared to the inlet point. The risk quotient, which was calculated using the concentrations of parent compounds, decreased toward the outlet, demonstrating the degradation capacity of the wetland. The estimates for biodegradability, hydrophobicity, and toxicity by an in-silico quantitative structure-activity relationship (QSAR) model indicated a lower half-life, lower logD_OW, and greater effect concentration for most TPs compared to the parent compounds. Based on these results, we conclude that natural wetlands play a role as an eco-friendly reactor for degrading SOCs to form numerous TPs that are lower risk than the parent compounds.

天然湿地已被公认为是降解和消除环境污染物的天然反应器。Upo湿地是韩国最大的内陆湿地，周围主要是农业用地，容易受到过多养分负荷和合成有机污染物（SOC）（例如农药）的污染。这项研究的目的是确定湿地中的主要SOC并评估其退化。我们使用高分辨率质谱（HRMS）用两步分析方法（即，1^日分析目标测量具有可疑和非靶筛选沿（SNTS）和2^次分析以进行免费的嫌疑人筛选），以识别和量化已识别的父级SOC的转化产物（TP）。对主要包括农药在内的30种目标物进行的定量分析表明，杀菌剂是湿地中检测到的主要SOC，约占定量SOC组成比的50％。谷胱甘肽的平均浓度最高（> 700 ng / L），然后是另外两种杀菌剂，多菌灵和三环唑。首次分析（SNTS）初步确定了14种母体农药的39种总磷（其中30种是可疑的，9种是非目标筛选的）。此外，第二次分析（免费嫌疑犯筛查）还确定了9个TP。在确定的48种总TP中，有7种已通过参考标准确认。其余TP的识别具有很高的置信度（例如，2或3级）。关于通过湿地的运输，与入口点相比，大多数TP在湿地的出口处显示出更大的峰面积比（即，TP与母体化合物的色谱面积的相对部分）。使用母体化合物的浓度计算得出的风险商向出口减小，表明湿地的降解能力。通过计算机内定量结构-活性关系（QSAR）模型估算的生物降解性，疏水性和毒性表明半衰期较低，logD较低 它是使用母体化合物的浓度计算的，向出口减少，表明湿地的降解能力。通过计算机内定量结构-活性关系（QSAR）模型估算的生物降解性，疏水性和毒性表明半衰期较低，logD较低 它是使用母体化合物的浓度计算的，向出口减少，表明湿地的降解能力。通过计算机内定量结构-活性关系（QSAR）模型估算的生物降解性，疏水性和毒性表明半衰期较低，logD较低与母体化合物相比，大多数TP的_OW效应浓度更高。根据这些结果，我们得出结论，天然湿地在降解SOCs以形成许多TPs的生态友好反应器中发挥了作用，而这些TPs的风险低于母体化合物。