Assessing the Ecological impacts of Sewage Sludge Recycling to Agricultural Land


Image Credit: thskyt 

Keywords: Wastewater management, sewage sludge, agriculture, analytical chemistry, pollution, sheep, health, ecosystem, organic chemicals

Project Summary: The sustainable management of sewage sludge (SS), the solid by-product of wastewater treatment, is a major challenge for the water industry. Current trends in waste management policy favour recycling of SS to agricultural land (EU Sewage Sludge Directive 86/278/EEC) as it is in line with the zero waste agenda. Despite recognised benefits of SS to improve soil fertility, SS contains a complex mixture of contaminants likely to enter the environment during land spreading. The concentrations of some pollutants/pathogens are regulated, however there are no regulations for anthropogenic trace organic contaminants (TrOCs) despite the presence of TrOCs such as petroleum compounds, flame-retardants, pharmaceuticals, personal care products, plastic additives and pesticides in SS; several which have shown health impacts in a range of taxa (including sheep1-5). For most chemicals in SS, their fate and impact on terrestrial ecosystems remains relatively understudied, moreover potential mixture effects/interactions between combinations of different chemicals present in SS is rarely considered. We propose here to develop methods that will assess the chemical and MP load in SS and related environmental samples. 

This studentship will determine how the global waste management practice of spreading human sewage sludge (SS) on agricultural land can impact terrestrial ecosystems. Animals which live/forage on SS treated pastures are at risk of exposure to unmonitored organic chemicals (including microplastics) found in SS. In order to determine ecological risks of this practice, EC loads to which animals living/foraging on SS pastures may be exposed urgently needs to be determined.

Methodology: Using analytical chemistry techniques, the project will quantify temporal environmental chemical (EC) loads in soil, soil invertebrates and sheep (wool and faeces) from already established SS treated agricultural land at the University of Glasgow Research Farm, following SS application to pasture.

The project will:

1) Develop and validate novel high-resolution comprehensive methods for non-targeted organic chemical analysis and MPs characterisation and quantification

2) Quantify TrOC loading/retention and loss from SS to the wider environment.

References 1. Bellingham et al (2016) J. Neuroendocrinology. 28(12). doi: 10.1111/jne.12444. 2. Bellingham et al (2013) Mol Cell Endocrinol. 376(1-2):156-72. 3. Bellingham et al (2012) Repro Dom Animal. 47:15-22 4. Bellingham et al (2010) J. Neuroendocrinol 22:527-533 5. Bellingham et al (2009) Environ Health Perspect. 117(10):1556-62.

Project Team: The supervisory team have complementary expertise to bring to this project.  Michelle Bellingham (primary supervisor) is a Lecturer in Physiology who has a track record of published work using SS application to agricultural land to examine the physiological effects of exposure to chemical mixtures using sheep. Caroline Gauchotte-Lindsay is a Lecturer in Environmental Engineering with expertise in developing high-resolution environmental analytical methods, coupled to advanced data mining to elucidate the fate of organic contaminants in natural and engineered environments.  Susan Waldron is a biogeochemist with a track record of published work in understanding how anthropogenic activities affect natural processes in the terrestrial and aquatic environments. The student will be based in the primary supervisor’s laboratory in the Institute of Biodiversity, Animal Health and Comparative Medicine (IBAHCM) but will also spend a proportion of time within the School of Engineering (SoEng). The student will have supervisory support within well-equipped research environments in both IBAHCM and SoEng.