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Assessing the risk to human health and the environment from mixed contamination


Polycyclic aromatic hydrocarbons and heavy metals: Joint toxicity evaluation and risk assessment


Characterisation of the nature of combined contaminants is a attracting much interest, with current assessments focusing mostly on single-pollutants. Humans are usually exposed simultaneously or sequentially to a variety of pollutants via multiple exposure routes. Joint effects of pollutants may be similar (additive) or dissimilar (synergistic or antagonistic). Polycyclic aromatic hydrocarbons (PAHs) and heavy metals are reported as the most common co-contaminants at former manufactured gas plant sites in Australia and other parts of world. Toxicity evaluation and risk assessment of these co-contaminants are very critical for remediation of these sites and also for human health.

Current methods of risk assessment have limitations which lead to uncertainty, and extra time and cost in the site assessment process due to the lack of reliable data on chemical mixture toxicity. For instance, available regulations for estimating mixture toxicities are based on an additive concept where interaction data are unavailable. The objective of this project is to determine the joint toxicity and risk assessment of PAHs and heavy metals. Outcomes from this project will help to make informed decisions about the real risk of mixed-contaminants and generate new knowledge on the toxicological effects of mixtures. This project fills data gaps needed for the risk-assessment of mixed contamination by generating scientifically based toxicological knowledge and also improve the current risk assessment methods by integrating the toxicity assays relevant to human health.


Sasikumar is Diplomate of The American Board of Toxicology (DABT) with post graduate qualifications in Veterinary Pharmacology & Toxicology. With around 8 years  of experience in toxicology, Sasikumar’s research began at the Drug Discovery unit of Dr. Reddy’s Laboratories Limited, India (GLP certified laboratory). He has conducted various types of toxicity studies in rodents and non-rodents and has experience in conduct of genotoxicity, in vitro toxicity and safety pharmacology studies. During this period, Sasikumar gained strong knowledge and experience in design and conduct of lead optimasation and GLP studies for new chemical entities (NCEs). His last assignment was as the Manager of the Toxicology Department in a reputed company where he managed the department of toxicology and animal facility. Sasikumar established a new animal facility during this period and overlooked the process of facility approval from Government of India.  He has managed a group of more than 5 people who were reporting to him during this period. To continue his learning of toxicology he started his PhD program at The University of Queensland, Brisbane which will help him to understand toxicity at molecular level and the art of risk assessment to human health.