Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers

Abstract

Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.

Engineered Biochar Production and Its Potential Benefits in a Closed-Loop Water-Reuse Agriculture System

“…Water scarcity can be quantity-based, quality-based, or based on the combined effect of the two [3]. In arid and semi-arid areas, groundwater is usually the single most important source of irrigation water [4]; however, with the prevalent overuse of synthetic fertilizers, groundwater is oftentimes very vulnerable to contamination due to the leaching of unutilized nutrients (e.g., nitrate (NO 3 − ) and nitrite (NO 2 − )) [5] and the flushing of dissolved elements of toxicological concern (e.g., As(III)) [6]. It is, therefore, critical to highlight the importance of conserving water quality while introducing extra sources of freshwater to increase water quantity in agricultural practices.…”

Enhanced As (V) Removal from Aqueous Solution by Biochar Prepared from Iron-Impregnated Corn Straw

“…With the rapid development of urban space and intensification of agricultural and industrial activities, chemical pollution has become a serious environmental issue, particularly in China [1,2]. Arsenic, as a potential carcinogen, is associated with a variety of human diseases, such as cardiovascular diseases, liver fibrosis, kidney disorders, blood toxicity, and chronic lung disease [3]. Arsenic's potential to pose a hazard to human health has prompted the establishment of more stringent environmental regulations and hence the development of innovative and cost-effective technologies for the treatment of arsenic in the environment.…”

High-resolution measurement and mapping of tungstate in waters, soils and sediments using the low-disturbance DGT sampling technique

“…element dispersion outwards. Since microbe could be a significant contributing factor of element desorption from (suspended) sediment particle [31,64,65], it can be assumed that the microbial desorption rate of W from the particle is still higher than the diffusion rate, therefore, the hotspots can maintain their enlargement. It should be pointed out that the hotspots would turn from genesis to senescence eventually, and it will be interesting, though challenging, to capture the later process and depict the life cycle of the hotspots.…”