Though the goal of the water treatment process is to ensure that harmful compounds from the environment do not enter the drinking water, more often than not the water treatment process itself produces a number of disinfection byproducts (DBPs), some of which are potential carcinogens. A group of DBPs are nitrosamines (link to downloadable PDF), many of which have been identified and measured in the effluent of wastewater plants.
The U.S. EPA’s Integrated Risk Information System (IRIS), a database containing toxicity information on hazardous substances, lists NDMA as a probable human carcinogen with a one in one million lifetime cancer risk in drinking water at a concentration of 0.7 ppt consumed by a 70-kg person drinking 2 liters of water per day. There is general agreement within the toxicological community that NDMA, even at very low concentrations, presents a health risk.
Unregulated Contaminant Monitoring Rule
In April 2012, the U.S. EPA signed the Unregulated Contaminant Monitoring Rule 3 (UCMR 3). This rule requires monitoring of 30 contaminants of emerging concern using EPA and/or consensus organization analytical methods during the 2013-2015 time periods. The EPA, the states, laboratories and public water systems (PWSs) are participating in the UCMR 3 efforts.
This rule requires that utilities serving greater than 10,000 customers test for the 30 environmental contaminants and submit the results to a central EPA database. Among the 30 contaminants being monitored as part of the UCMR3 efforts are six nitrosamines, including NDMA. Data collected under UCMR 3 will assist in regulatory determination and a contaminant’s potential impact on human health.
Largest Water Purification System in the World
Orange County’s $480 million Groundwater Replenishment System (GWRS), in the state of California in the U.S., is the largest water purification project of its kind in the world and the system started a $142.7M USD expansion in January 2012. The AWQAL at Orange County Water District (OCWD) conducts 400,000 water analyses per year and the Laboratory manages the large groundwater basin that underlies north and central Orange County, providing water to 2.4 million people in 20 cities.
Under the direction of Lee Yoo, Laboratory Director, the lab performs complete California Title 22 drinking water analyses, wastewater analyses, microbiological coli form and heterotrophic bacteria testing, VOCs, base/neutral organic compounds, emerging contaminants, nitrosamines in water, and many others types of analysis.
Challenges for Environmental Testing Laboratories
For a detailed account of some of the challenges faced by environmental testing laboratories and the sample preparation bottlenecks in the analytical testing process that may result in poor analyte recoveries and highly variability, be sure to attend an on-demand webinar, titled, Automated Solid Phase Extraction for the Environmental Testing Laboratory (link to registration page; you will need to fill a brief registration page after which the webinar will play on-demand).
The first part of the webinar talks about the many challenges that laboratories face when preparing samples and the use of automated sample preparation to help improve sample processing turnaround times.
The second part of the webinar presents data from the Orange County Water District where eight nitrosamines, 1, 4-dioxane and other emerging contaminants are monitored at sub parts per trillion levels. The webinar discusses the use of sample flow rate, elution time, drying time, and nitrogen gas flow rate as key operational parameters within the solid-phase extraction process to optimize the analytical step.