Spatial variability in the ambient concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans across the Middle East

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) were monitored at 12 sites across four countries (Kuwait, Turkey, Lebanon and, Oman) using validated passive air samplers between January 2018 and December 2018 in an attempt to set up a monitoring network for persistent organic pollutants (POPs) across the Middle East. The highest concentrations of ΣPCDD/F were detected in Oman reflecting the proximity of the site to a steel melting company at Al-Rassil Industrial area (557 fg I-TEQ m⁻³) and a hospital waste incinerator at Al-Multaga (489 fg I-TEQ m⁻³). Elevated levels were also measured at all monitoring sites across Kuwait with average concentrations ranging from ∼150 fg I-TEQ m⁻³ at the Shuwaikh site to ∼250 fg I-TEQ m⁻³ at the Salmiya and Abdali sites. Levels of ΣPCDD/F at all other stations in the region were generally lower than 35 fg I-TEQ m⁻³. The levels of 1,2,3,4,7,8-HxCDF were frequently a factor of two higher compared to 1,2,3,6,7,8-HxCDF suggesting that an additional source exists which involves the use of elemental chlorine. This study has provided the first reliable measurements of the atmospheric concentrations of PCDD/F in the Middle East providing a baseline for assessing time trends in PCDD/F in the air, one of the core matrices for the effectiveness evaluation under the Stockholm Convention on POPs.