What we find in New Orleans tap water after Mardi Gras

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Opioid drugs including oxycodone, heroin and fentanyl have fueled an ever-worsening epidemic in the US. And after giant events in New Orleans they are popping up in the wastewater.

The post What we find in New Orleans tap water after Mardi Gras appeared first on Green Prophet.

Mardi Gras is a time when illicit drugs appear in the wastewater.In early 2025, the party-loving city of New Orleans, Louisiana, hosted two major events within the span of a month: Super Bowl LIX and Mardi Gras. And, as with many major events, it appears there was an increase in recreational drug use during this time. Researchers publishing in ACS’ *Environmental Science & Technology Letters* show how monitoring wastewater revealed an increase in the use of relatively new dangerous synthetic opioids during these two events.

“Our study reveals the growing trend of synthetic opioid use in communities and our non-invasive approach to detect these emerging drugs, helping public health officials to respond more effectively and shape informed policies,” explains Ramesh Sapkota, an author of the study.

Opioid drugs including oxycodone, heroin and fentanyl have fueled an ever-worsening epidemic in the US. And after giant events in New Orleans they are popping up in the wastewater.

Synthetic opioids such as nitazenes are emerging as new drugs that are being misused. Nitazenes were first developed as an alternative to morphine in the 1950s but carried too high an overdose risk for clinical use. However, they re-emerged in the illicit drug market around 2019. And although they frequently appear in overdose-related deaths, not all jurisdictions are monitoring for them yet.

For example, Louisiana’s Department of Health reported that 46% of overdose deaths in 2023 were caused by opioids, but none officially report nitazene involvement, contradicting the national trends reported by the US Centers for Disease Control and Prevention.

And their most commonly found nitazene analogue, metonitazene, is 1,000 times more potent than morphine.

To monitor this emerging risk, Sapkota, Emilia Lomnicki and Bikram Subedi turned to a method that could provide near real-time, non-invasive results: wastewater monitoring. They say this is the first time that this technique has been used to track several nitazene compounds in municipal wastewater.

The researchers specifically focused on the period surrounding and including the Super Bowl and Mardi Gras in New Orleans (Jan. 23 to March 31, 2025) and collected a total of 28 samples from a treatment plant estimated to serve nearly 300,000 people. The analyses detected seven of the nine nitazenes down to trace levels in wastewater. And their most commonly found nitazene analogue, metonitazene, is 1,000 times more potent than morphine. Surprisingly, some analogues were found at similar levels during the week of the big events and the week after, and some were only found after Mardi Gras had concluded.

These estimates do not provide insight into the consumption rate of nitazene analogues because the excretion rates of these drugs must be understood first. However, early detection of these dangerous substances is incredibly important, especially during high-traffic events like those studied here.

“With this knowledge, valuable insight into the evolving dynamics of the overdose crisis is gained, and a discussion on public health responses to combat these illicit drugs and prevent further loss of life is opened,” concludes Lomnicki.

Wastewater treatment facilities do not adequately filter drugs and chemicals from drinking water and tap water. While some studies show high removal rates (>90%) for certain drugs, others indicate that many opioids, particularly synthetic ones, pass through standard treatment, leading to their release into environmental waters.

The post What we find in New Orleans tap water after Mardi Gras appeared first on Green Prophet.