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Cycle 5 (2015 Deadline)

Developing exposure and toxicity data for trace organic chemicals in wastewater, biosolids, and soils

PI: Bice Martincigh (, University of KwaZulu-Natal
U.S. Partner: Natalie Mladenov, San Diego State University
Project Dates: February 2017 - January 2020

Project Overview:

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Dr. Chris Buckley at the wastewater treatment plant at Newlands Mashu
Contemporary lifestyles and the extensive use of organic chemicals in personal care and consumer products (PCCPs) leads to the constant discharge of enormous quantities of chemical residues from industries and homes into wastewater streams and, ultimately, the environment. In contrast to heavy metals, pathways of trace organic chemicals (TOrCs) derived from manufacturing and use of PCCPs are varied in the wastewater stream . The majority of TOrCs that reach wastewater treatment plants are destroyed through treatment and sludge processing, but recalcitrant TOrCs and their metabolites can pass through the treatment process intact and partition, dependent on their physico-chemical properties, in biosolids and aqueous media. Very little is known about the fate of TOrCs in the climatic context of South Africa.

This team has chosen to study a set of four classes of potential pollutants: flame retardants, the broad-spectrum herbicide glyphosate (Ro undup®, ubiquitously used in the local sugarcane industry), antibiotics, and HIV anti-retrovirals. Effluents from wastewater treatment plants in the Durban area, sewage sludge, biosolids, soils from effluent-irrigated farm land, and sludge and/or biosolid-amended soils will be analyzed and characterized for the presence of these TOrCs.

This project will have access to the local DEWATS wastewater treatment plant, which allows for detailed studies on the fate of the TOrCs during their passage through the plant and subsequent agricultural areas, providing a confined and controlled environment. Comprehensive target and non-target analytical techniques will be developed to detect and quantify the four classes of compounds in the selected matrices.

Furthermore, the team will develop a simultaneous extraction and clean-up method for each chemical compound class in the above-mentioned matrices.

Summary of Recent Events

In this reporting period, PhD student Ms. Tolulope Lawrence spent three months at the University of Bath in the laboratories of Prof. Barbara Kasprzyk-Hordern, a researcher on emerging contaminants and their metabolites. This exchange visit forms part of the INTERWASTE program funded by the European Union’s Horizon 2020 research and innovation program. The training Ms. Lawrence received was invaluable and greatly facilitated the analyses of the project’s samples. Ms. Lawrence has analyzed the samples from the five Durban treatment plants for 69 pharmaceutical and personal care products (PPCPs). Of these compounds, only 35 were detected in the samples, while 10 were below the limit of quantification. The PPCPs identified were mainly analgesics, anti-cancer drugs, antidepressants, human indicators, stimulants, and antibiotics, among others. The data collected is still being processed, but to date the PI reports that they have found that the removal efficiency of the plants for certain compounds, such as the sunscreen benzophenone-3, is poor. Also, there is a build-up of the metabolites of certain pharmaceuticals, such as carbamazepine. Once the data for all five plants have been processed, the researchers should gain a clearer understanding.

The analyses of the samples for HIV-ARV drugs and glyphosate content is continuing. Studies of the photolysis of HIV-ARV drugs under solar irradiation have been carried out both in water and wastewater. Lastly, the PEER team has initiated plant uptake studies of various trace organic compounds. They are growing four crops: rye grass, radish, dry bean, and green pepper. These are being grown in various types of soils, including biosolids from one of the wastewater treatment plants. The researchers will subsequently analyze these crops for the uptake of glyphosate and its metabolite, as well as some HIV-ARV drugs and PPCPs.

The PI Dr. Bice Martincigh was elected as a Member of the Academy of Science of South Africa and inaugurated on October 9, 2019.

In the next project year, the PEER team will continue with the analyses of the samples collected. In addition, the plants grown in sludge-amended soils should be ready for harvesting and analysis for the uptake of various micro-pollutants. PhD student Ms. Lerato Mollo will visit the U.S. partner in order to conduct non-target analyses for which her lab in South Africa lacks the necessary facilities. In addition, PhD student Mr. Muhammad Lawal will visit the University of Birmingham under the auspices of the INTERWASTE project to conduct analyses on his samples.

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Chemistry lab at UKZNThe UKZN project team and PEER Project Manager

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