Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in municipal and industrial effluents

•45 industrial and municipal effluent streams were sampled for PCDD/Fs.•Industrial discharges contained the most PCDD/F contamination and highest WHO-TEQs.•2,3,7,8-TCDD was the major WHO-TEQ contributor.•Industries had higher TSS, TDS, TOC, DOC and higher PCDD/F in the suspended phase.•PCDD/F concentrations in the suspended phase were 25× greater than dissolved phase.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were quantified in 45 effluent samples in the Houston Ship Channel (HSC) system in Texas. Total PCDD/F concentrations ranged from 0.16 to 13.23 pg L−1 in the dissolved phase and from 0.79 to 682.27 pg L−1 in the suspended phase. Generally, industrial facilities contained more PCDD/F contamination than municipal wastewater treatment plants or refuse facilities. World Health Organization Toxic Equivalents (WHO-TEQs) ranged from 0.007 to 0.279 pg L−1 in the dissolved phase and 0.021–1.851 pg L−1 in the suspended phase. The major TEQ contributor was 2,3,7,8-TCDD and overall, TEQs were greatest in industrial effluents. A correlation between high solids and high PCDD/F concentrations was observed and based on the results obtained in this study, the abundance of suspended solids may have largely contributed to high PCDD/F contamination in the suspended phase. Homolog profiles revealed that PCDD/F contamination increased with increasing chlorination and the highest concentrations were primarily from the octa-chlorinated congeners (OCDD/F) in both the dissolved and suspended phase.