Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans in Storm Water Outfalls Adjacent to Urban Areas and Petroleum Refineries in San Francisco Bay, California

Abstract

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in storm water collected from 15 outfalls in San Francisco Bay, California, considered representative of areas located adjacent to petroleum refineries and mixed urban/commercial/residential land uses. Storm water sampling was conducted hourly over a 12-h period at two outfalls located near the city of Oakland and the suburban community of Benicia, which represent urban and mixed urban/light industrial land uses, respectively. Sampling was conducted hourly to determine temporal changes in the concentrations and distributions of PCDD/Fs during the first major rainstorm event of the 1995/96 winter season. In addition, storm water sampling was conducted in December 1995 and February/April 1996 at six publicly owned treatment work (POTW) outfalls located adjacent to developed, undeveloped, mixed residential/commercial, and industrial lands. Storm water sampling also was conducted at five outfalls located adjacent to petroleum refineries. The sampling results were used to examine changes in PCDD/F loadings to San Francisco Bay at the onset and midway through the winter rainy season and to characterize differences in PCDD/F concentrations, if any, between refinery and nonrefinery areas. The concentrations of tetra- through octa-chlorinated homologues and 2,3,7,8-substituted congeners were assayed in filtered storm water samples according to US EPA Method 1613A. Principal components analysis (PCA) was used as an exploratory technique to examine the similarities and differences in the distributions of PCDD/Fs in storm water from different outfalls. The sampling results showed few significant differences between storm water discharged from outfalls located in mixed urban/commercial/residential areas and outfalls located adjacent to petroleum refineries. The concentrations of 2,3,7,8-TCDD were below the analytical limits of detection in all storm water samples, with the exception of samples collected after the sixth hour of sampling at the Oakland outfall. Fingerprint patterns were generally dominated by the higher chlorinated PCDD/F congeners including OCDD, OCDF, and 1,2,3,4,6,7,8-HpCDD. Total TEQs were generally below US EPA ambient water quality criteria and aquatic ecotoxicology guideline values. The results of this study strongly suggest that discrete sampling of storm water outfalls is insufficient to characterize the concentrations and distributions of persistent hydrophobic contaminants such as PCDD/Fs. In addition to surface water runoff from the city of Oakland, other nonindustrialized urban locations may represent important sources of PCDD/Fs to San Francisco Bay.http://link.springer-ny.com/link/service/journals/00244/bibs/37n3p290.html

Concentrations and loads of PCBs, dioxins, PAHs, PBDEs, OC pesticides and pyrethroids during storm and low flow conditions in a small urban semi-arid watershed

“…Note only one low flow sample was collected in this study and therefore may not well represent the range of concentrations during low flow conditions. Nevertheless, these findings are not dissimilar to those reported by Wenning et al (1999), who collected two grab samples at each of six mixed land use watersheds around the San Francisco Bay Area and reported a range of 0.161-10.6 ng/l. At two locations Wenning et al also collected grab samples hourly over the course of a storm in which the range widened from 0.042-10.5 and 0.018-3.01 ng/l at their Oakland and Benicia sites, respectively.…”

“…Previous studies have shown that the most toxic compound in this group (2378-TCDD) occurs in relatively lower concentrations than some of the less toxic compounds in the group (Suarez et al, 2006). Despite inadvertent generation, dioxin compounds appear to be ubiquitous even in watersheds with no local sources (Wenning et al, 1999). Data on dioxin loadings appears to be relatively rare.…”

“…In the Bay Area, since there are no major local point sources, stormwater runoff has been identified as the greatest source of dioxins to the Bay (Gervason and Tang, 1998). Despite high toxicity, surprisingly few studies have reported concentrations of dioxins in urban runoff (Wenning et al, 1999;Suarez et al, 2006;Bryant Jr. and Goodbred, 2009). Previous studies have shown that the most toxic compound in this group (2378-TCDD) occurs in relatively lower concentrations than some of the less toxic compounds in the group (Suarez et al, 2006).…”

“…Based on previous studies that have characterized a wide range of pollutant concentrations and loads to the Bay (e.g. Wenning et al, 1999;She et al, 2002;Greenfield and Davis, 2005;Oros et al, 2005;Davis et al, 2007;Oram et al, 2008;Weston et al, 2009;Weston and Lydy, 2010;David et al, 2015), the San Francisco Bay Regional Water Quality Control Board has specified urban stormwater runoff in the total maximum daily loads reports as a large and potentially controllable source of pollutants for enhanced management (e.g. Water Board, 2008).…”