Sources and fate of high levels of ammonium in surface water and shallow groundwater of the Jianghan Plain, Central China

Abstract

High levels of ammonium from anthropogenic sources threaten the quality of surface waters and groundwaters in some areas worldwide, but elevated ammonium levels of natural sources also have been identified. High levels of ammonium have been detected in both surface water and shallow groundwater of the Jianghan Plain, an alluvial plain of the Yangtze River. This study used N isotopes coupled with ancillary chemistry to identify ammonium in this region. Ammonium in the Tongshun River (up to 10.25 mg L) showed a sharp accumulation in the upstream and gradual attenuation in the downstream. The δN values of ammonium in the TSR were high and ranged narrowly from +12.5 to +15.4‰, suggesting an anthropogenic source that was septic effluent from industrial waste discharge. Sorption and nitrification were likely to respectively serve as the principal processes contributing to ammonium attenuation in different reaches of the downstream TSR. In shallow groundwater, high levels of ammonium (up to 14.10 mg L) occurred in a reducing environment. The narrow δN variation with low values (+2.3 to +4.5‰) in the lower aquifer suggested a natural source that was organic N mineralization. The δN values in the shallow aquitard exhibited a wide range from -1.8 to +9.4‰, owing to various sources. Two types of water in the shallow aquitard could be identified: (1) type-1 water with relatively longer residence time was similar to those in the aquifer where ammonium was mainly sourced from organic N mineralization; (2) type-2 water with shorter residence time was jointly affected by surface input, chemical attenuation and mineralization of organic N. The aquitard prevents prompt ammonium exchange between the surface and aquifer, and the shallower part of the aquitard provides a sufficient reaction time and an active reaction rate for ammonium removal.

Fuzzy Optimization for the Remediation of Ammonia: A Case Study Based on Electrochemical Oxidation

“…Excessive discharge of nutrients into water bodies, mainly due to anthropogenic activities [1], has profound global environmental and health effects. High levels of nitrogen contributes to algal bloom in receiving surface waters resulting in depletion of dissolved oxygen and production of toxins that are harmful to aquatic organisms [2].…”

Nutrient chemistry and eutrophication risk assessment of the Ghaghara river, India

“…NH 4 þ and NO 3 À are the most dominant species of dissolved inorganic nitrogen in the aquatic ecosystem. The average concentration of NH 4 -N ion in the Ghaghara river was 3 to 8 times more than the unpolluted river indicating the contribution from the addition of sewage and industrial waste, atmospheric wet, and dry deposition, and runoff from agriculture and animal feedlot areas however concentration was within the permissible limit given by BIS () (Table 2) (Miller et al 2011;Du et al ). The NH 4 -N ion concentration showed significant spatial and seasonal variation (p < 0.05) in the Ghaghara river (Table 3).…”

Determinants of Declining Water Quality

“…Photosynthesis by algae and plants uses hydrogen, thus increasing pH levels, while respiration and decomposition can lower pH levels. Most bodies of water are able to buffer these changes due to their alkalinity, so small or localized fluctuations are quickly modified and may be difficult to detect (Sheiham, 1981, USGS, 2016 Sewage from industrial emission or leakage of manure and fertilizers from agricultural activities and urban land extent had higher positive relationship to ammonium (Shi et al, 2015, Du et al, 2017.…”