Anthropogenic impacts on lake and stream water quality are well established but have been much less studied in wetlands. Here we use data from the 2016 National Wetland Condition Assessment to characterize water quality and its relationship to anthropogenic pressure for inland wetlands across the conterminous USA. Water samples obtained from 525 inland wetlands spanned pH from < 4 to > 9 and 3 to 5 orders of magnitude in ionic strength (chloride, sulfate, conductivity), nutrients (total N and P), turbidity, planktonic chlorophyll, and dissolved organic carbon (DOC). Anthropogenic pressure levels were evaluated at two spatial scales – an adjacent scale scored from field checklists, and a catchment scale indicated by percent agricultural plus urban landcover. Pressure at the two spatial scales were uncorrelated and varied considerably across regions and wetland hydrogeomorphic types. Both adjacent- and catchment-scale pressure were associated with elevated ionic-strength metrics; chloride elevation was most evident in road-salt using states, and sulfate was strongly elevated in a few sites with coal mining nearby. Nutrients were elevated in association with catchment-scale pressure but concomitant changes were not seen in planktonic chlorophyll. Acidic pH and high DOC occurred primarily in upper Great Lakes and eastern seaboard sites having low anthropogenic pressure, suggesting natural organic acid sources. Ionic strength and nutrients increased with increasing catchment-scale pressure even in Flats and closed Depression and Lacustrine sites, which indicates connectivity to rather than isolation from upland anthropogenic landuse even for wetlands lacking inflowing streams.

人为对湖泊和溪流水质的影响已得到充分证实，但对湿地的研究却少得多。在这里，我们使用 2016 年国家湿地状况评估的数据来描述美国本土内陆湿地的水质及其与人为压力的关系。从 525 个内陆湿地获取的水样的 pH 值范围为 < 4 至 > 9，离子强度（氯化物、硫酸盐、电导率）、营养物质（总氮和总磷）、浊度、浮游叶绿素和溶解有机碳的范围为 3 至 5 个数量级（文档）。人为压力水平在两个空间尺度上进行评估——一个是根据现场检查表评分的相邻尺度，另一个是由农业加城市土地覆盖百分比表示的流域尺度。两个空间尺度上的压力不相关，并且在不同区域和湿地水文地貌类型之间差异很大。邻近和流域规模的压力都与离子强度指标的升高有关；氯化物升高在使用路盐的州最为明显，而硫酸盐在附近有煤矿开采的一些地点急剧升高。养分升高与流域规模压力相关，但浮游叶绿素没有观察到伴随的变化。酸性 pH 值和高 DOC 主要发生在人为压力较低的五大湖上游和东部沿海地区，表明天然有机酸来源。即使在平地和封闭的洼地和湖泊地点，离子强度和养分也随着流域规模压力的增加而增加，这表明即使对于缺乏流入溪流的湿地，也与高地人为土地利用存在连通性而不是隔离。