Posted by Duncan Heal on 31 August 2017
Emerging Organic Contaminants (EOCs) have been defined as synthetic or naturally-occurring chemicals or any microorganisms not commonly monitored in the environment, but which have the potential to enter the environment and cause known or suspected adverse ecological and (or) human health effects (Stewart et al. 2016). Municipal wastewater treatment plant (WWTP) effluent is recognised as a major source of EOCs into the environment. The Nelson Regional Sewerage Business Unit (NRSBU) contracted the Cawthron Institute and Northcott Research Consultants Limited (by subcontract) to analyse a suite of EOCs in the effluent from the Bell Island WWTP.
The concentrations of EOCs measured in the effluent of the Bell Island WWTP are considerably lower than those recognised to represent a risk to freshwater and marine organisms. This suggests EOCs represent a negligible risk to aquatic organisms in the receiving environment. In addition, the effluent will be subject to dispersion and dilution upon discharge to the environment, which would further reduce the concentrations of these EOCs. EOCs entering the receiving environment are likely to be subject to loss and removal through a range of microbial and chemical degradation processes, and adsorption to sediment particles.