Withdrawn 10th Australian Stream Management Conference 2021

The geochemistry of cocaine and ecological impacts in the Hawkesbury-Nepean river (#43)

Jason K Reynolds 1 , Bianca Russom 1 , Ian Wright 1 , Mark Williams 1
  1. Western Sydney Univeristy, Penrith, NSW, Australia

1. Sydney is commonly referred to as the cocaine capital of Australia in the National Wastewater Drug Monitoring Program. The quantification of cocaine and its metabolites in untreated wastewater in these monitoring programs has seen estimations of cocaine use in NSW reach over 1g/1000people/day. Our research question was to understand the potential for the treated wastewater to contain cocaine and/or its metabolites upon discharge to waterways. And, if cocaine was present to understand if the concentrations were of ecological concern. 

2. The research program collected discharge water from four seperate wastewater treatment plants that discharge into the Hawkesbury-Nepean river system. Samples were collected across seasons and multiple years. The collected waters were assessed cocaine using LC-MS using a unique approach developed in-house. To better understand the potential for degradation of cocaine in environmental waters a series of incubation studies were undertaken and monitored the stability of cocaine in Hawkesbury-Nepean river water. The collected data was modelled to better understand the stability of cocaine in natural waters and potential degradation products. 

3. The outcomes of this work highlight that cocaine is discharged into the Hawkesbury-Nepean river system at levels that are comparable to other densely populated cities internationally. We have found that the chemistry of cocaine degradation in our studied environmental waters varies to existing laboratory studies.

4. The implications of this work are that environmental waters in rapidly urbanising catchment areas such as the Sydney region are increasingly under pressure from trace amounts of illicit compounds. 

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