Mangroves are among the most productive coastal ecosystems; however, they are prone to anthropogenic pollution due to their land-sea interface position. We used stable nitrogen isotopes and spectrophotometric nitrate analysis to study the anthropogenic pollution in five mangrove ecosystems in Tanzania, including two polluted (Mzinga and Kizinga), one moderate (Kunduchi) and non-polluted (Mbegani and Ras Dege) sites. Also, we tested the suitability of mangrove leaves, roots, sediment, and gastropod as indicators of anthropogenic nitrogen pollution using stable δ¹⁵N isotope analysis. Results revealed higher than 10‰ δ¹⁵N values in all analysed components and the highest nitrate concentrations of 16.44 mg L⁻¹ in the interstitial waters at the polluted sites, indicating anthropogenic nitrogen inputs. The δ¹⁵N enrichment increased in the order: non-polluted < moderate < polluted. The polluted sites are fed by freshwater creeks and probably receive high loads of domestic sewage from the surrounding communities, industries, and agricultural effluents. Therefore, to protect mangrove ecosystems, proper waste and wastewater management upstream are recommended.

红树林是生产力最高的沿海生态系统之一。然而，由于它们的陆海界面位置，它们易于受到人为污染。我们使用稳定的氮同位素和分光光度硝酸盐分析法研究了坦桑尼亚五个红树林生态系统的人为污染，其中包括两个污染（Mzinga和Kizinga），一个中等（Kunduchi）和非污染（Mbegani和Ras Dege）场所。此外，我们测试红树叶，根，沉积物的适合性，并腹如使用稳定δ人为氮污染的指标^15点ñ同位素分析。结果表明高于10‰δ ¹⁵在所有分析的部件的N值和16.44毫克的L的最高的硝酸盐浓度^-1在受污染地点的间隙水中，表明人为氮输入。的δ ¹⁵无公害<中度<污染：N富集的顺序增加。受污染的地点由淡水小溪喂养，并可能从周围社区，工业和农业废水中吸收大量生活污水。因此，为了保护红树林生态系统，建议在上游进行适当的废物和废水管理。