The findings emerged when Louisiana’s southern coast residents faced saltwater intrusion from the Gulf of Mexico. Since the summer of 2023, the combination of drought and rising sea levels helped drag the salty water from the ocean to the Mississippi River. The high levels of saltwater have made much of the region’s water undrinkable. But public health experts have also voiced worries that the saltwater intrusion could, over time, corrode the region’s aging water infrastructure, leach heavy metals into the drinking water, and create other problems.
Most tap water throughout the United States gets treated with solutions that kill off bacteria and viruses. However, this treatment process creates disinfection byproducts. Small quantities of disinfection byproducts may be harmless; however, when seawater enters a water treatment plant, the byproducts formed by disinfecting seawater are especially toxic.
According to recent state water tests reviewed by the Guardian newspaper, along Louisiana’s Gulf coast, there has been a significant increase in the contaminants known as disinfection byproducts. According to the Environmental Protection Agency (EPA), long-term exposure to such substances poses an increased risk of cancer.
The findings emerged when Louisiana’s southern coast residents faced saltwater intrusion from the Gulf of Mexico. Since the summer of 2023, the combination of drought and rising sea levels helped drag the salty water from the ocean to the Mississippi River. The high levels of saltwater have made much of the region’s water undrinkable. But public health experts have also voiced worries that the saltwater intrusion could, over time, corrode the region’s aging water infrastructure, leach heavy metals into the drinking water, and create other problems.
Orleans Parish, Louisiana
In August 2023, The Environmental Protection Agency released a set of public water system testing data for the highly toxic fluorinated compounds (PFAS), also known as “forever chemicals,” known as required by its Fifth Unregulated Contaminant Monitoring Rule, or UCMR5. The EWG’sts of tests conducted by New Orleans Carrollton Waterworks and provided to the Environmental Working Group by the Louisiana Department of Health and Hospitals showed 32 total contaminants exceeded EWG Health guidelines.
Plaquemines Parish, Louisiana
Recent state testing in the lower Plaquemines parish revealed a spike in two groups of compounds that result from the water disinfection process. The EPA has stated that long-term exposure to these groups of chemicals carries an increased risk of cancer.
Port Sulfur, Louisiana
The Port Sulphur water district has also revealed high levels of disinfection byproducts – trihalomethanes (THMs) and haloacetic acids (HAA5s) – since 2021. Both groups of substances have been linked to cancer by the EPA.
Although the water district released a public notice in August 2023, acknowledging that total THM levels were above the EPA standard of 80 parts per billion (ppb), earlier testing detected total THM levels at 135 ppb and 128 ppb, according to the notice. The public notice stated that neither the Louisiana State Health Department nor the EPA “consider this violation to have any serious adverse health effects on human health as a result of short-term exposure.”
However, a test by the state health department on 5 September found that the total THMs within the Port Sulphur water district (serving 9K residents) jumped to 761ppb, or almost ten times the maximum amount allowed by EPA regulations.
Multiple tests showed exceptionally high levels of one toxigenic THM, bromoform, created by disinfecting bromide, a compound naturally occurring in seawater. The EPA classifies bromoform as a probable human carcinogen.
Experts agree
Experts agreed that the saltwater intrusion triggered the most recent spike in disinfection byproducts. The EPA regulates disinfection byproducts in drinking water to ensure levels stay low. Long-term exposure has been linked to cancer and reproductive effects in lab animals. One study attributed 5% of all bladder cancers in the European Union to THMs. There is also limited evidence to suggest THMs and HAA5s increase the risk for colorectal, breast, and uterine cancers.
Many residents of the Port Sulphur district have stopped drinking tap water since June due to its saltiness, but THMs are also readily absorbed through the skin and inhaled as steam during warm showers. By some estimates, exposure from just a 10-minute shower is roughly equivalent to drinking 2.5 liters (0.66 gallons) of water.
Disinfection byproducts and PFAS can be lowered by reducing the amount of organic matter in the water – such as by installing a carbon filter or reverse osmosis machine. Port Sulphur’s water treatment plant recently utilized reverse osmosis and microfiltration machinery to stop the THMs.