Investigation Of Polybrominated Diphenyl Ethers In Wastewater Treatment Plants Along The Us And Mexico Border: A Trans-Boundary Study
A comprehensive investigation of polybromodiphenyl ethers (PBDEs) in wastewater was conducted in the second largest international metroplex area along the U.S. and Mexico (MX) border. Concentrations of PBDEs in wastewater and sludge were measured in four wastewater treatment plants (WWTPs) in El Paso, Texas and two WWTPs in Cd. Juarez, Chihuahua, MX. A green approach in sample preparation technique, called stir bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography and mass spectrometry, was used which requires minimum amount of organic solvents and has good sensitivity at nanogram-per-liter levels for wastewater samples and nanograms per gram for waste sludge solids. Concentrations of PBDEs ranged from 30.2 to 342 ng L−1 in wastewater influents, from not detected to 209 ng L−1 in effluents, and from not detected to 1,303 ng g−1 in sludge. Among 27 PBDEs studied, BDE-47, BDE-99, and BDE-100 were the most commonly detected congeners in all samples. Further evaluation showed that secondary and tertiary treatments are highly effective at removing PBDEs from wastewater with percent removals ranging from 84 % to 100 %, while advanced primary treatment only removed 41–73 % of PBDEs. As a complement, the ambient air temperature change on PBDEs concentrations was evaluated finding that this factor did not have an influence on the PBDEs concentrations in WWTPs. The incomplete removal of PBDEs in WWTPs implicates a potential impact on the environmental and public health as a result of the continuous release of PBDEs from the WWTPs to the Rio Grande River and irrigation canals.