title: PCB dry and wet weather concentration and load comparisons in Houston-area urban channels.
abstract: All 209 PCB congeners are quantified in water in both dry and wet weather urban flows in Houston, Texas, USA. Total water PCBs ranged from 0.82 to 9.4ng/L in wet weather and 0.46 to 9.0ng/L in dry. Wet weather loads were 8.2 times higher (by median) than dry weather with some increases of over 100-fold. The majority of the PCB load was in the dissolved fraction in dry weather while it was in the suspended fraction in wet weather. Dissolved PCB loads were correlated with rain intensity and highly developed land area, and a multiple linear regression (MLR) equation was developed to quantify these correlations. PCA generated five PCB components with nearly all positive loadings. They were interpreted as DOC-associated A1248, wet weather primarily suspended fraction A1254/A1260 likely from building sealants, truly dissolved-associated wastewater dechlorination, watershed-sourced PCB 11, and monochlorinated PCBs (likely connected to a different state or source of dechlorination). The PCB 11 component was statistically higher in wet versus dry weather when no other component showed such clear distinctions. Hierarchical cluster analysis (HCA) did not always group dry and wet weather samples from the same location together illustrating the different congener composition that often exists between dry and wet conditions. Four wet weather samples from high percentage developed land (>90%) watersheds had nearly the same fingerprint suggesting a generic "urban" signature in runoff, which in this case was caused by residual A1254/A1260 PCB stocks and currently produced PCB 11 in consumer goods.
authors.affiliation: Department of Civil and Environmental Engineering, University of Houston, 4800 Calhoun, Eng Bldg 1, Room N107, Houston, TX, USA. nlhowell@uh.edu
authors.forename: Nathan L
authors.initials: NL
authors.lastname: Howell
authors.forename: Divagar
authors.initials: D
authors.lastname: Lakshmanan
authors.forename: Hanadi S
authors.initials: HS
authors.lastname: Rifai
authors.forename: Larry
authors.initials: L
authors.lastname: Koenig
mesh_terms: D002947:Cities; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D016014:Linear Models; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D013781:Texas; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*; D014887:Weather
chemical_list: D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls