Sulfate (SO₄²⁻) is an essential nutrient for the growth of several agricultural crops. However, higher than normal SO₄²⁻ runoff into rivers and streams can cause environmental impacts including acidification, heavy metal release, phosphorus remobilization, and methylmercury release in aquatic systems. The city of Winkler, Manitoba, Canada, uses groundwater for its municipal needs. Some of the wells have a high SO₄²⁻ content that is stripped off and discarded into the municipal sewage lagoons which are biannually emptied into an adjacent creek (Dead Horse Creek, DHC). However, sewage lagoon effluent is not the only input source of SO₄²⁻. Culvert drainage and soil runoff from the surrounding agricultural fields also contribute SO₄²⁻ to DHC. During the summers of 2011, 2012, and 2018, sewage lagoons, culverts, wells, precipitation, soil, and fertilizers were sampled from the DHC area near Winker, Manitoba. Isotopic compositions (sulfur and oxygen) for all potential SO₄²⁻ inputs to DHC have been determined. In this study, a dual-isotope approach was employed in combination with Stable Isotope Analysis in R (SIAR) Bayesian probability analysis to estimate the contributions of all potential SO₄²⁻ sources to DHC. The Winkler sewage lagoons were found to be the primary SO₄²⁻ contributor, an outcome which is directly related to the disposal of concentrated SO₄²⁻ waste from the City of Winkler’s water treatment plant. In addition, runoff of soils (through culverts) was also determined to be a significant contributor of SO₄²⁻ to DHC. Based on the results of this study, it is recommended that the City of Winkler’s Waste Water Treatment Plant incorporate a process to remove the high SO₄²⁻ concentrations from the lagoons prior to the release of sewage effluent into DHC.

硫酸盐（SO ₄ ^2-）是几种农作物生长的必需营养素。但是，高于正常水平的进入河流和溪流的SO ₄ ^2-径流会导致环境影响，包括酸化，重金属释放，磷固位和甲基汞在水生系统中的释放。加拿大曼尼托巴省温克勒市利用地下水满足市政需求。一些井中的SO ₄ ^2-含量很高，被剥离后丢弃到市政污水池中，该污水池每半年倒入一条相邻的小溪（Dead Horse Creek，DHC）。然而，污水池污水不是SO ₄ ^2-的唯一输入源。。来自周围农田的涵洞排水和土壤径流也为DHC贡献了SO ₄ ^2-。在2011年，2012年和2018年夏季，从曼尼托巴省Winker附近的DHC地区采样了污水泻湖，涵洞，水井，降水，土壤和肥料。已经确定了向DHC的所有潜在SO ₄ ^2-的同位素组成（硫和氧）。在这项研究中，将双同位素方法与R（SIAR）贝叶斯概率分析中的稳定同位素分析结合使用，以估算所有潜在SO ₄ ^2-来源对DHC的贡献。发现Winkler污水泻湖是主要的SO ₄ ²⁻贡献者，其结果与Winkler市水处理厂中浓SO ₄ ^2-废物的处置直接相关。此外，土壤（通过涵洞）的径流也被确定为DHC的SO ₄ ^2-的重要贡献。根据这项研究的结果，建议温克勒市的废水处理厂采用在将污水排放到DHC中之前，先从泻湖中去除高SO ₄ ^2-浓度的工艺。