Resources and Risks: Perceptions on the Application of Sewage Sludge on Agricultural Land in Sweden, a Case Study

Nelson Ekane,Karina Barquet,Arno Rosemarin

doi:10.3389/fsufs.2021.647780

Abstract

To spread or not to spread sewage sludge on agricultural land in Sweden remains the subject of a highly polarized debate among different stakeholders in the Swedish agricultural sector. This article presents insights on how stakeholders in Sweden see and explain the potentials and safety of spreading sewage sludge on agricultural land. This is done by drawing on risk perception literature and qualitative research methods. The findings reveal that fear of contamination and feeling of disgust are major deterrents of the use of sludge as an agricultural input. These are partly explained by unknowns and unfamiliarity about risks of unwanted substances in sludge. The study shows that while actors engaged in the practice amplify benefits of sludge as a resource and reiterate the need for emphasis on upstream measures including improved risk management systems, actors in charge of controlling toxins in society amplify actual and potential risks, highlight gaps in monitoring and minimizing risks, and would rather have a complete ban on the practice. This study highlights the complex combination of technical, environmental, socio-economic, psychological, and political factors influencing judgment and decision-making regarding sludge and its use as fertilizer in agriculture and concludes that the clash between facts and feelings which epitomizes the Swedish sludge debate may have implications for public trust and effective risk communication. As contribution to the Swedish sewage sludge debate, this study emphasizes that the benefits of sludge in agriculture is important but not enough to drive the practice to scale. It is even more important to improve understanding on the controllability and severity of risks in short and long-term.

Highlights

Over 200,000 tons of sewage sludge1 are produced in Sweden each year, a large proportion of which is used for topsoil production and covering landfills (SOU, 2020:3)
To make this point even more concrete the farmer adds that—“spraying pesticides on crops may be more dangerous than spreading sludge as an agricultural input, but spraying pesticides is an acceptable risk for many people.”
What is particular about sludge that makes it unacceptable if pesticides and sludge both pose risks? The origin, nature, and characteristics of sludge seem to be an important explanatory factor as the expert from wastewater treatment plants (WWTPs) 2 asserts—“it is more about perceived risks and stigma linked to wastes of human origin than the actual

Summary

Introduction

Over 200,000 tons of sewage sludge are produced in Sweden each year, a large proportion of which is used for topsoil production and covering landfills (SOU, 2020:3). From a risk point of view, sewage sludge contains undesirable substances such as heavy metals (Cd, Cu, Hg, Ni, Pb, Zn), non-degradable microplastics, pathogens, antibiotics, and other antimicrobial substances, emerging groups of chemical substances such as per and polyfluorinated hydrocarbons or PFAS3 and substances of concern which can potentially cause harm to human and environmental health if not properly or safely managed (Rockefeller, 1998; Buck et al, 2011; KSLA, 2013; Posner et al, 2013; Tóth et al, 2016; SAM, 2018; Hudcova et al, 2019; EFSA CONTAM Panel et al, 2020; European Food Safety Authority (EFSA), 2020) Even valuable nutrients such as P pollute aquatic and terrestrial ecosystems when applied in excess or indiscriminately to agricultural land through chemical fertilizers, sewage sludge, and animal manure (Kleinman et al, 2015; Barreau et al, 2018; Bol et al, 2018; Smits and Woltjer, 2018; Powers et al, 2019). Even the application of other resources such as cattle manure and pig slurry on agricultural land is relatively more acceptable, even though these substances have been shown to pose risks to human and environmental health (Pell, 1997; Köpke et al, 2007; Polprasert, 2007; Zhang, 2011; Dufour et al, 2012; Ekane et al, 2016; Pedersen et al, 2019)

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