Earlier this week, Algiers residents received notice that the New Orleans West Bank water supply failed to achieve the minimum percentage reduction for total organic carbon (TOC) required by the Louisiana State Sanitary Code.
According to the Sewerage and Water Board of New Orleans (SWBNO), this failure isn’t an emergency, and the water remains safe to drink.
Measuring TOC is a way to determine how contaminated a water supply is. Organic contaminants from natural organic substances, insecticides, herbicides, industrial wastewater, and more can enter the rivers and streams and contaminate the drinking water supply. In some cases, treatment processes are not enough to completely remove these contaminants.
The notice sent out by the SWBNO insists that TOC on its own has no health effects. However, it does create an environment where disinfectants used in the treatment of the area’s drinking water can combine with organic matter to form byproducts (DBPs) such as trihalomethanes (THMs) and (HAAs). Those byproducts in higher concentrations can cause kidney or liver problems, affect the nervous system and lead to an increased risk of cancer.
According to SWBNO, the Algiers water supply is still well below the maximum contaminant level standards for THMs and HAAs. While water utilities are required to lower their TOC amounts in the drinking water supply by a percentage, there is no maximum contaminant level for TOC.
The SWBNO was required to achieve a removal ratio of 1.00 or greater for TOC. In the fourth quarter of 2018, the ratio achieved was only 0.89.
The SWBNO states that they are making improvements to the Algiers water treatment plant in order to improve TOC removal and bring them into compliance with the Louisiana Sanitary Code’s removal requirements.