Detection of N-nitrosodimethylamine (NDMA) in Israel's complex water/wastewater cycle

Yaal Lester, Azrieli College of Engineering Jerusalem, Jerusalem, israel (lester.yaal@gmail.com)

N-Nitrosodimethylamine (NDMA) is a semi-volatile potent organic chemical, formed as a by-product of certain manufacturing processes such as rubber manufacturing and others. More importantly, NDMA may be generated during chemical disinfection of drinking water and wastewater by chlorine, chloramine and ozone. In fact, due to the widespread use of chlorine and ozone for water treatment and the high toxicity of NDMA (much higher than known disinfection by-products such as trihalomethanes), this chemical is now considered an emerging disinfect by-product of health and regulatory concern. Exposure to NDMA is possible through direct consumption of disinfected drinking water or through consumption of groundwater affected by wastewater discharge. Israel is the only western country where no study was ever conducted on the presence of NDMA in the water cycle. This is more surprising in light of the country's complex water supply system, which comprise a mixture of desalinated water, ground- and surface water. The goal of this study is to monitor NDMA concentration throughout Israel's water system, identify important sources and potential risks.

To do so, we first optimized a detection method based on EPA method 521, employing coconut charcoal cartridges solid phase extraction (SPE) and GC/MS. Subsequently, we analyzed large number of water samples taken from different locations: Tap water from the cities Tel Aviv, Jerusalem and Hadera (comprising of groundwater: desalinated water mixture at different ratios), wastewater effluent from Shafdan and Gihon wastewater reclamation facilities, groundwater from the coastal aquifer and more.

We could detect NDMA at significant concentrations in many of the analyzed samples. For example, 24.5 ng/L NDMA were detected in tap water at Tel Aviv, comprising of 80% desalinated water. Since NDMA could not be detected in reverse osmosis permeate, we estimate that its presence in Israel's drinking water mostly originates from contaminated groundwater.   

 

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Short Biography of Presenting Author

Yaal Lester was born in Israel in 1972. He graduated as environmental engineer at Israel’s Institute of Technology (Technion, Haifa) in 2005, and received his MS.c. and Ph.D from the environmental engineering program at Tel Aviv University (2012). His post doctorate studies were carried out at the University of Colorado (Boulder), after which he returned to Israel and was reintegrated as the head of the Environmental Technologies Laboratory at Azrieli – College of Engineering Jerusalem. Dr. Lester overarching research interests include advanced treatment processes of water and wastewater, focusing on the development and mechanistic study of oxidation/reduction processes for the treatment of emerging contaminants. Other fields of research include the characterization and treatment of industrial wastewaters and the development of sustainable microalgae-based processes and their use as wastewater treatment solutions.