Manure-borne pathogens as an important source of water contamination: An update on the dynamics of pathogen survival/transport as well as practical risk mitigation strategies.

Abstract

Enteropathogen contamination of water resources is a global concern. Several sources and routes of pathogen contamination of water resources have been identified including agriculture. Land spreading or disposal of manure/livestock wastes is a notable source of public health relevant microorganisms into water. Microorganisms can be transported from manure-amended soils into water, from where they can reach animals and humans and may cause infection. This review explores the public health relevance of manure-borne-pathogens, highlighting some of the diseases that manure associated pathogens cause. It also examines the dynamics of overland transport of pathogens into surface waters and percolation through soils into groundwater. Factors that influence the survival and transport of pathogens into respective water resources are discussed. The actual number of pathogens shed, pathogen release rate, requisite flow conditions, precipitation characteristics and pathogen inactivation potential are some general factors, examined in this review. Pathogen adaptation and survival in the soil environment is extensively discussed because soils significantly influence pathogen transfer into water. In addition to soil characteristics, environmental variables such as moisture, temperature and pH as well as soil biology are relevant aspects, considered herein. Manure and farm management practices such as manure source and type, storage and treatment, also influence the occurrence, survival and transport potential of pathogens. Optimized and recommended manure treatment techniques like composting, which has been demonstrated to satisfactorily inactivate enteric pathogens in manure are discussed. The need for proper composting by observing recommended manuring stipulations is emphasized and finally, practical strategies to protect water resources from pathogenic contamination are elucidated.