Impacts of leachates from livestock carcass burial and manure heap sites on groundwater geochemistry and microbial community structure

Abstract

We investigated the impacts of leachates from a swine carcass burial site and a cow manure heap on the geochemical and microbiological properties of agricultural water samples, including leachate, groundwater from monitoring wells and background wells, and stream water. The leachate from the livestock burial site showed extremely high electrical conductivity, turbidity, and major ion concentrations, but low redox potential and dissolved oxygen levels. The groundwater in the monitoring wells adjacent to both sites showed severe contamination from the leachate, as indicated by the increases in EC, turbidity, Cl-, and SO42-. Bacteria from the phylum Firmicutes and Bacteriodetes and Archaea from the phylum Euryarchaeota were the major phyla in both the leachates and manure heap. However, the class- or genus-level components of these phyla differed markedly between the leachate and manure heap samples. The relative abundance of Firmicutes decreased from 35% to 0.3~13.9% in the monitoring wells and background wells at both sites. The Firmicutes in these wells was unlikely to have originated from the transportation of leachate to the surrounding environment because Firmicutes genera differed drastically between the leachate and monitoring wells. Meanwhile, sulfate-reducing bacteria (SRB) from the livestock carcass burial site were detected in the monitoring wells close to the leachate. This was likely because the release of carcass decomposition products, such as organic acids, to adjacent areas improved the suitability of the local environments for SRB, which were not abundant in the leachate. This study highlights the need to better understand microbial community dynamics along groundwater flow paths to evaluate bacterial transport in subsurface environments and provides new insights into the effective management of groundwater quality at both farm and regional scales.

The Social Costs of Keystone Species Collapse: Evidence from the Decline of Vultures in India

“…Livestock agriculture also becomes a source of water pollution when farmers need to dispose of dead animals (Engel et al 2004;Kwon et al 2017). A 2016 Supreme Court ruling in the state of Uttarkhand recognized that animal carcass dumping in water bodies is an ongoing problem, even in water bodies that are considered sacred: "It is tragic that the Ganga, which has since time immemorial, purified the people is being polluted by man in numerous ways, by dumping of garbage, throwing carcass of dead animals and discharge of effluents" (Sharma and Singh 2016).…”

“…Water Quality Disposal of dead livestock is a known water pollution source (Engel et al 2004;Kwon et al 2017), and water quality deteriorates in the absence of scavengers (Swift et al 1979;Santori et al 2020;Brundage 2021). This concern has been noted in the specific setting of the vulture collapse in India: "as there were hardly any vultures left, the carcasses were not disposed of.…”

Аntibiotic resistance of bacterial cultures isolated from the feral pigeon (Columba livia) and starling (Sturnus vulgaris) at a solid waste landfill

“…Landfilling without prior separation and depollution leads to soil and groundwater contamination due to seepage of toxic leachate such as toxic organic pollutants, antibiotics, pharmaceuticals and personal care products and heavy metals too. The latter can penetrate during rain through disposable waste and contaminate soil and groundwater (Kwon et al, 2017;Yu et al, 2020).…”

Potential Environmental and Human Health Risks Caused by Antibiotic-Resistant Bacteria (ARB), Antibiotic Resistance Genes (ARGs) and Emerging Contaminants (ECs) from Municipal Solid Waste (MSW) Landfill

“…Despite years of globalization, landfilling is unfortunately still one of the most common old-fashioned methods that are not perfectly designed to stop contamination in soil and groundwater through toxic leachate percolation. Landfill leachate contains undesirable toxic materials, such as organic pollutants, antibiotics, pharmaceutical and personal care products (PPCPs), and heavy metals, that can be percolating during rainfall through disposable waste and contaminate mainly the soil layers and groundwater [ 12 , 13 ]. All these toxic pollutants are harmful to the survival of aquatic life and the food web that can cause various problems for human health, including genotoxicity and cancer-causing effects.…”