UCLA Civil & Environmental Engineering Department

C&EE 200

Environmental Engineering and Hydrology & Water Resources

Degradation of Endoxifen in Water, Treated Wastewater and Receiving Surface Water                       by Ultraviolet and Sunlight

Prof. Ekalak Khan

University of Nevada Las Vegas

Endoxifen is an effective metabolite of tamoxifen, a commonly used chemotherapy drug, and has been detected in the final effluent of a municipal wastewater treatment plant (WWTP). Endoxifen has emerged as a potential breast cancer drug based on a recently completed clinical trial. Endoxifen in the water environment could bring negative effects to aquatic lives as demonstrated by its toxicity to Daphnia pulex. Our research group has investigated ways to degrade endoxifen and found that it is biorecalcitrant but very photodegradable. Endoxifen in water was degraded by at least 99.1% after 35 seconds of ultraviolet (254 nm) irradiation. Photodegradation of endoxifen in treated wastewater at ultraviolet (UV) doses used for disinfection in WWTPs resulted in reduction of endoxifen by 30 to 71%. Endoxifen in treated wastewater was photodegraded by sunlight at 83%, whereas in receiving surface water it was photodegraded at 61% after 150 min of irradiation. Multiple photodegradation by-products (PBPs) were identified for both the cases of UV and sunlight radiation and almost all of them are potentially more toxic than endoxifen itself. The adoption of endoxifen as a breast cancer drug should proceed with extreme caution as highly toxic PBPs are potentially generated if endoxifen is present in treated wastewater disinfected by UV radiation and in receiving surface water exposed to sunlight.

Where:   1200B Kinsey Science Teaching Pavilion

When:     1:00 – 1:50 PM, Tuesday, January 14, 2020

Dr. Eakalak Khan is a professor in the Civil and Environmental Engineering Dept. at the University of Nevada, Las Vegas. He has been there two years and before that he was a professor and department chair in the Civil and Environmental Engineering Department at North Dakota State University in Fargo. He is a 1997 graduate of UCLA where he performed research on water reclamation topics included the development of biodegradable organic carbon methodologies. He has continued to work on biological methods for water and wastewater treatment technologies. He is a registered professional engineer and a fellow of the Water Environment Federation.