Wastewater reuse in irrigation: A microbiological perspective on implications in soil fertility and human and environmental health

Abstract

The reuse of treated wastewater, in particular for irrigation, is an increasingly common practice, encouraged by governments and official entities worldwide. Irrigation with wastewater may have implications at two different levels: alter the physicochemical and microbiological properties of the soil and/or introduce and contribute to the accumulation of chemical and biological contaminants in soil. The first may affect soil productivity and fertility; the second may pose serious risks to the human and environmental health. The sustainable wastewater reuse in agriculture should prevent both types of effects, requiring a holistic and integrated risk assessment. In this article we critically review possible effects of irrigation with treated wastewater, with special emphasis on soil microbiota. The maintenance of a rich and diversified autochthonous soil microbiota and the use of treated wastewater with minimal levels of potential soil contaminants are proposed as sine qua non conditions to achieve a sustainable wastewater reuse for irrigation.

Supplementation of Nutrients for Table Beets by Irrigation With Treated Dairy Effluent

“…The micronutrients were not altered by the applied treatments (Table 3). Several authors (Prazeres et al, 2014;Herpin et al (2007); Gomes et al, 2009;Becerra-Castro et al, 2015;Azevedo & Oliveira, 2005;Pereira et al, 2011) that have been working with crops irrigated with treated effluents of organic origin, mainly domestic sewage, also obtained similar results for the presence of macronutrients in the soil and a decrease in soil acidity, satisfactory in tropical soils. The sodium values and the percentage of exchangeable sodium in the soil (Table 3) were also higher in treated dairy effluents.…”

Antibiotic resistance in urban aquatic environments: can it be controlled?

“…While some studies suggest that ARG in soils do not vary significantly due to irrigation with treated wastewater, others demonstrate that at least some genes tend to accumulate in soils after a continued exposure to wastewater (Negreanu et al 2012;Wang et al 2014;Becerra-Castro et al 2015). Another potential risk for the dissemination of ARB&ARG is the use of sewage sludge for agriculture soil fertilization, which has been suggested as presenting a high potential of spreading through both soils and crops (Rahube et al 2014).…”

Discharge of swine wastes risks water quality and food safety: Antibiotics and antibiotic resistance genes from swine sources to the receiving environments

“…Manure fertilizer has been reported to increase the abundance of antibiotic resistance in soils (Wu et al, 2010;Zhu et al, 2013;Heuer et al, 2011;Udikovic-Kolic et al, 2014) and in harvested vegetables (Marti et al, 2013). This may pose potential risks to food safety and human health (Becerra-Castro et al, 2015). So far, scientific knowledge on the impact of swine farming on the adjacent environments and vegetables is still limited; therefore, further research is essential to investigate the dissemination of ARGs associated with disposal of animal wastes.…”