Gareth Lewis (PhD Student)
University of South Australia 

Project Title
Fate and dynamics of Endocrine Disrupting Chemicals (EDCRs) and Pharmaceutically Active Compounds (PhACs) in the Soil Environment

Biography
Gareth completed a Masters of Applied Science (Environmental Toxicology) at the University of Adelaide studying “The impact of herbicides on biota of the intertidal zone” in 2003. Prior to completing his M. Appl. Sci. he worked as a scientific officer in several contract positions at Primary Industries of South Australia (1997-98, Farm Chemicals Section), the Engineering and Water Supply (1994-96) Department (Bolivar, S.A.) and Anesthesia Labs. (1989-92, Royal Adelaide Hospital) and in Clinical Biochemistry (1988-89, Flinders University of South Australia). After completing his M. Appl. Sci Gareth was employed at the University of South Australia as a research assistant investigating the effect of fire fighting foams in the terrestrial environment.

Start Date
September 2006

Project Details
Human activity produces biological waste as sewage and as manures from intensive farming practices (pig, poultry and dairy production). Biological waste that animals produce contains chemicals that are either produced naturally, within the animal, or are taken by the animal to maintain its health. Over 90% of the (pharmaceutically active compounds, PhACs) chemicals that animals ingest are excreted, either as the parent chemical or as metabolites of the parent chemical. Human waste that enters sewage treatment plants is treated and is transformed into pellets (biosolids) that are then applied to agricultural land. However, animal manures are often applied to land without prior treatment.

It is estimated that 40 000 tons of biosolid (from human waste) are applied to agricultural land per annum in South Australia for the purpose of grain production while biosolid production in the USA is anticipated to be 8 million tons per annum by the year 2010. Therefore, disposal of PhAC-contaminated biological waste is of increasing concern to waste management authorities and to the scientific community. The concern arises because PhACs , such as endocrine disrupting chemicals (EDCRs) and antibiotics, may leach or desorb from biosolid-amended land to then have a negative impact on biota. It is known that these chemicals can potentially adversely impact on the normal growth, development and reproduction of animals (caused by EDCRs) and contribute to the development of multiple antibiotic resistant bacteria (caused by sub-therapeutic doses of antibiotics).

The current research topic will therefore focus on the potential of chemicals within biosolid-amended land to become mobile and then negatively impact on ecological endpoints such as the endocrine system (at the level of the estrogen receptor) and the development of antibiotic resistance.