In Situ Measurements of Polychlorinated Biphenyls in the Waters of San Diego Bay, California

Abstract

Sediments of San Diego Bay (SDB) are known to contain elevated levels of polychlorinated biphenyls (PCBs). While numerous efforts have been made to monitor the spatial or temporal trends of contamination in SDB, no studies have been directed toward measurements of water column contamination. We measured PCB concentrations in the water column of SDB with an in situ sampling system. Except for one sample collected near the bay mouth, all other samples contained higher PCB concentrations than the 30-day average discharge limit established by the California Ocean Plan. The highest concentrations of water column PCBs occurred in the Central Bay, consistent with the previous findings that sediments in the Central Bay contained higher PCB levels than those in the North and South Bays. Based on the water volume of 2.2 x 10(8) cm3 at a lower water level, it was estimated that approximately 1,000 g of PCBs is transported out of SDB via tidal exchange annually. This indicates that water column transport driven by tidal exchange is a viable mechanism reducing PCB contamination within SDB.

Fate of PCB Congeners in an Industrial Harbor of Lake Michigan

“…The dissolved-phase represents 61% of ΣPCB in water (all samples). Similar dissolved/particulate PCB distributions have been reported by many studies in different locations (34, 36). Surficial sediment ΣPCB concentrations have been previously reported (13) and ranged from 53 to 35,000 ng g −1 d.w. (n=60) with an arithmetic mean of 7,400±6,700 ng g −1 d.w.…”

Polybrominated diphenyl ethers, dechlorane plus, and polychlorinated biphenyls in tree bark near the upper Yellow River, China

“…However, some halogenated flame retardants, such as polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP), are persistent in the environment, bioaccumulate in biota, and can be transported long distances in the atmosphere. There are worldwide concerns about these chemicals because of their ubiquity in the environment; PBDEs, DP, and PCBs have been found in the atmosphere [3][4][5], water [6][7][8], sediment [9,10], biota [11,12], and humans [13][14][15]. Polychlorinated biphenyls have been designated as persistent organic pollutants (POPs) by the Stockholm Convention [2].…”

Development of a Combined Solid-Phase Extraction-Supercritical Fluid Extraction Procedure for the Determination of Polychlorinated Biphenyls in Wastewater

“…The hygienic threshold values for each PCB congener in drinking water is 100 ng/L, 4 but when investigating the transport properties in a water environment, detection limits below 1 ng/L are sometimes required. [5][6][7][8][9][10][11] The need to determine very low concentrations of PCBs in natural water and wastewater samples calls for large concentration enrichment factors before a final determination is possible. This can be accomplished by liquid-liquid extraction (LLE), such as in the US EPA Method 608.…”

“…7 An alternative way of extracting PCBs from water is solid-phase extraction (SPE), as described in the US EPA Method 525. 13 SPE has been applied to extract PCBs from water samples in a number of investigations, [8][9][10][11][14][15][16][17] but very few have reported data for natural waters. SPE was used to extract five congeners in river water using 1 L water samples showing PCB levels in the low ng/L range.…”

“…8,9 However, when analyzing PCBs in seawater, more than 1000 L of a sample had to be used in order to determine the concentrations at the pg/L level. 10,11 Both approaches have their shortcomings, such as foaming in LLE, and plugging in SPE. In the latter case, the problem can often be solved by using glass-fiber filters to filtrate the water before it reaches the SPE-disk.…”