Anthropogenic sources of total phosphorus (TP) and chloride (Cl⁻) to lakes and rivers have been issues of concern for many decades in the Great Lakes Basin with northern Boreal Shield headwater tributaries less well studied. In the Sturgeon River – Lake Nipissing – French River basin, a headwater basin of Georgian Bay, Lake Huron, water quality monitoring of major inflows to Lake Nipissing, the third largest inland lake located entirely within Ontario, is only available from the mid-1960s to the 1990s. During the period of 2015–2018, we conducted monthly water quality surveys of major and minor inflows for two water years and have generated the first chloride (Cl⁻) and total phosphorus (TP) elemental budgets for the lake. Review of available long-term concentration data indicate decreasing TP concentrations by decade in major inflows, but select inflows continue to exhibit concentrations above provincial objectives, including inflows from agricultural areas that are no longer part of provincial monitoring programs. Some inflows also show high average Cl⁻ concentrations with potential influences (e.g., road salt, agricultural activities) to stream water quality throughout the year. Water and elemental budgets indicate that while specific runoff (l/s/km²) is quite similar across contributing catchments, yields of Cl⁻ and TP (kg/ha/yr) are disproportionately higher in catchments with urban and agricultural activities. While uncertainties in the water balance and elemental yields remain, this first effort to quantify annual elemental budgets of Lake Nipissing highlights the need to develop community-based, spatially distributed water quality surveying for long-term ecosystem monitoring and future planning.

几十年来，湖泊和河流的总磷 (TP) 和氯化物 (Cl ^- ) 的人为来源一直是五大湖盆地关注的问题，而北部北部地盾源头支流的研究较少。在鲟鱼河 - 尼皮辛湖 - 法国河流域，乔治亚湾的源头盆地，休伦湖，仅在 1960 年代中期才可对流入尼皮辛湖（完全位于安大略省内的第三大内陆湖泊）的主要流入量进行水质监测到 1990 年代。在 2015-2018 年期间，我们对两个水年度的主要和次要流入量进行了月度水质调查，并产生了第一个氯化物 (Cl ^-) 和湖泊的总磷 (TP) 元素预算。对现有长期浓度数据的审查表明，主要流入量的 TP 浓度下降了十年，但选定的流入量继续表现出高于省级目标的浓度，包括不再属于省级监测计划的农业区的流入量。一些流入量还显示出较高的平均 Cl ^-浓度，对全年河流水质有潜在影响（例如，道路盐分、农业活动）。水和元素预算表明，虽然具体径流 (l/s/km ² ) 在贡献的集水区非常相似，但 Cl ^-和 TP (kg/ha/yr) 在有城市和农业活动的集水区不成比例地高。虽然水平衡和元素产量的不确定性仍然存在，但首次量化尼皮辛湖年度元素预算的努力强调了开发基于社区的、空间分布的水质调查以进行长期生态系统监测和未来规划的必要性。