Department of Environmental Science and Engineering, Research Centre for Resource and Environment, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, People's Republic of China.
Environ Sci Pollut Res Int. 2022 Mar;29(14):20357-20369. doi: 10.1007/s11356-021-16930-8. Epub 2021 Nov 4.
The Beiyun river flows through a hot spot region of Beijing-Tianjin-Hebei in China that serves a majority of occupants. However, the region experiences severe nitrate pollution, posing a threat to human health due to inadequate self-purification capacity. In that context, there is an urgent need to assess nitrate levels in this region. Herein, we used δN-NO, δO-NO isotopes analysis, and stable isotope analysis model to evaluate the nitrate source apportionment in the Beiyun river. A meta-analysis was then used to compare the potential similarity of nitrate sources among the Beiyun riverine watershed and other watersheds. Results of nitrate source apportionment revealed that nitrate originated from the manure and sewage (contribution rate: 89.6%), soil nitrogen (5.9%), and nitrogen fertilizer (3.9%) in the wet season. While in the dry season, nitrate mainly originated from manure and sewage (91.6%). Furthermore, different land-use types exhibited distinct nitrate compositions. Nitrate in urban and suburban areas mostly was traced from manure and sewage (90.5% and 78.8%, respectively). Notably, the different nitrate contribution in the rural-urban fringe and plant-covered areas were manure and sewage (44.3% and 32.8%), soil nitrogen (26.9% and 35.7%), nitrogen fertilizer (23.5% and 29.4%), and atmospheric deposition (5.3% and 2.0%). Through a meta-analysis, we found nitrogen fertilizer, soil nitrogen, and manure and sewage as the main nitrate sources in the Beiyun riverine watershed or the other similar complexed watersheds in the temperate regions. Thus, this study provides a scientific basis for nitrate source apportionment and nitrate pollution preventive management in watersheds with complexed land-use types in temperate regions.
北运河流经中国京津冀热点地区，为大多数居民提供服务。然而，该地区硝酸盐污染严重，由于自净能力不足，对人类健康构成威胁。在这种情况下，迫切需要对该地区的硝酸盐水平进行评估。在这里，我们使用 δN-NO、δO-NO 同位素分析和稳定同位素分析模型来评估北运河流域的硝酸盐源分配。然后使用荟萃分析来比较北运河流域和其他流域硝酸盐源的潜在相似性。硝酸盐源分配的结果表明，硝酸盐在雨季主要来自粪肥和污水（贡献率：89.6%）、土壤氮（5.9%）和氮肥（3.9%）。而在旱季，硝酸盐主要来自粪肥和污水（91.6%）。此外，不同的土地利用类型表现出不同的硝酸盐组成。城市和郊区的硝酸盐主要来自粪肥和污水（分别为 90.5%和 78.8%）。值得注意的是，城乡边缘和植被覆盖地区的硝酸盐贡献不同，粪肥和污水（分别为 44.3%和 32.8%）、土壤氮（26.9%和 35.7%）、氮肥（23.5%和 29.4%）和大气沉降（5.3%和 2.0%）。通过荟萃分析，我们发现氮肥、土壤氮和粪肥和污水是北运河流域或温带其他类似复杂流域的主要硝酸盐源。因此，本研究为温带复杂土地利用类型流域的硝酸盐源分配和硝酸盐污染防治管理提供了科学依据。
