Scientists find toxic substance from cocaine users' urine is not fully removed by wastewater treatment

Analysis of treated wastewater from two Welsh plants has revealed the presence of a chemical associated with cocaine consumption, and shows that less than three quarters of the substance is removed by conventional wastewater treatment. The research team at Bournemouth University said its findings “suggest that improvements to treatment processes could be needed”.

Research elsewhere, conducted in 1994, showed the same chemical “may play a role in altering newborn behaviour,” and other studies have shown it could be toxic to aquatic life.

The Bournemouth study measured concentrations of benzoylecgonine – the chief substance excreted in urine following cocaine use – in wastewater samples before and after treatment from Friday to Monday every week over the course of two months.

The results, the scientists said, revealed “significant” levels of cocaine use in the surrounding area.

They found that the average daily consumption of cocaine during the testing period was 3.88mg per one thousand people near one of the treatment plants, and 1.97mg per thousand people near the other. The highest daily rate observed was 8.54mg per thousand people, which occurred after a weekend when the number of people in the area was boosted by an international rugby match in Cardiff.

According to their findings, an average of 73% of benzoylecgonine was removed during treatment - meaning that traces remained in the water that went back into the region. This, they noted, highlights the necessity for enhanced monitoring and treatment strategies to address public health and environmental concerns.