Sewage Wastewater and Sludge as Source of Traditional and Emerging Contaminants in Agroecosystems

Abstract

The enormous release of untreated sewage wastewater (330 km3) and sludge containing contaminants like antibiotics, antibiotic resistance genes, heavy metals, metalloids, personal care products, infectious microorganisms including coliforms and hormones into agroecosystem has been documented to pose severe risks to food chain and crop productivity. The sludge amount produced in European Union would rise to approximately 12 million tonnes by 2020. Surprisingly, nearly 30–60% of antibiotics get concentrated in treatment facilities, serving as source of environmental contaminants and 30–90% of antibiotics used in livestock may release in nature without any modification. The heavy metal content in sewage sludge with respect to dry weight may reach upto 0.5–2%. The recently rising interest of farmers in organic farming has accelerated the employment of sewage wastewater and sludge as an innovative source of irrigation water and fertilizers, respectively so as to augment crop production, minimize the agrochemical exploitation and overcome the associated threats to agricultural productivity. Although, multifaceted beneficial effects of sewage water and sludge deployment in agriculture are reported worldwide, the introduction of traditional as well as emerging contaminants like antibiotics, personal care products, and hormones in food chain via utilization of sewage wastewater and sludge cannot be denied. Therefore, the proper treatment is imperative to nullify the unforeseen consequences of sewage wastewater and sludge utilization in agroecosystem.We review recent information regarding the sewage application in agriculture, commonly observed traditional and emerging contaminants, major bottlenecks during application, potential benefits and risks of using sewage water and sludge for management of crop productivity and techniques currently being practiced for sequestration of contaminants. The information on various organic and inorganic contaminants present in sewage wastewater and sludge could be helpful in predicting the toxicity to agroecosystem, threats of accumulation in crop produce and hence human health. In depth information pertinent to source fingerprinting, assessment, ecotoxicology along with different aspects of fate and transport of important contaminants would help foster in the design and application of sustainable strategies and improvement in currently employed tools for the management of globally produced huge amounts of sewage wastewater and sludge.KeywordsAgrochemicalsAgroecosystemAntibioticsCrop productivityOrganic agriculturePersonal care products