Potential Sources of Ammonium-Nitrogen in the Coastal Groundwater Determined from a Combined Analysis of Nitrogen Isotope, Biological and Geological Parameters, and Land Use
Potential Sources of Ammonium-Nitrogen in the Coastal Groundwater Determined from a Combined Analysis of Nitrogen Isotope, Biological and Geological Parameters, and Land Use
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DOI：
10.3390/w13010025
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发表时间：
2020-12
期刊：
影响因子：
3.4
通讯作者：
A. Rusydi;S. Onodera;M. Saito;F. Hyodo;M. Maeda;K. Sugianti;S. Wibawa
中科院分区：
文献类型：
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作者：
A. Rusydi;S. Onodera;M. Saito;F. Hyodo;M. Maeda;K. Sugianti;S. Wibawa
印度尼西亚沿海地下水中氨氮的来源尚未得到深入研究，同时浓度升高仍是一个令人担忧的问题。这项研究旨在追踪印度尼西亚因德拉马尤地下水中氨氮的潜在来源，那里的地下水对生计至关重要。根据结果，对氮同位素、大肠菌群、土地利用和地质的联合检查证实了地下水中氨氮的自然和人为来源。在微咸水养殖区，地下水的δ15NNH4值为+1.8~+4.8NNH4值，表明氨氮来源于有机氮向氨氮的矿化。此外，铵与钠呈显著正相关，表明交换性铵通过阳离子交换进入地下水。同时，在农业和居民区检测到了人为废弃物中的氨氮。地下水的δ15NNH4值变化较大，从−2.9到+16.1‰，这意味着粪便、矿肥、污水和坑厕等几种来源的氨氮有衰减。此外，大肠杆菌的存在证实了人类和动物排泄物受到污染的迹象。然而，由于铵与钠没有关系，阳离子交换是不可行的，氨氮随液体废物从人为来源进入地下水。
The origin of ammonium-nitrogen in Indonesian coastal groundwater has not been intensively examined, meanwhile the elevated concentration remains a concern. This research aims at tracing the potential sources of ammonium-nitrogen in the groundwater of Indramayu, Indonesia where groundwater is vital for livelihood. From results, a combined examination of nitrogen isotope, coliform bacteria, land-use, and geology confirmed the natural and anthropogenic origins of ammonium-nitrogen in the groundwater. In the brackish-water aquaculture region, groundwater has δ15NNH4 values from +1.8 to +4.8‰ signifying that ammonium-nitrogen is derived from mineralization of organic nitrogen to ammonium. Furthermore, ammonium has a significantly positive relationship with sodium indicating the exchangeable ammonium is mobilized to groundwater via cation exchange. Meanwhile ammonium-nitrogen from anthropogenic waste was detected in agricultural and residential region. The groundwater has more varied δ15NNH4 values, from −2.9 to +16.1‰, which implies attenuation of ammonium-nitrogen from several sources namely manure, mineral fertilizer, sewage, and pit latrines. Also, the presence of E. coli confirms the indication of human and animal waste contamination. However, since ammonium has no relationship with sodium, cation exchange is not feasible and ammonium-nitrogen flows into the groundwater from anthropogenic sources along with liquid wastes.