Air−Water Exchange of Polychlorinated Biphenyls in the Delaware River

Abstract

The air-water exchange of polychlorinated biphenyls (PCBs) often results in net volatilization, which is thought to be the most important loss process for PCBs in many systems. Previous investigations of the air-water exchange of PCBs have been hampered by difficulties in treatment of the uncertainty in the calculation of air/water fugacity ratios. This work presents a new framework for the treatment of uncertainty, where uncertainty in physical constants is handled differently from random measurement uncertainty associated with random samples, and it further investigates the sorption of PCBs to colloids (dissolved organic carbon). Simultaneous measurements of PCBs in the air and water of five water quality management zones of the Delaware River were taken in 2002 in support of the total maximum daily load (TMDL) process. Gas-phase concentrations of IPCBs ranged from 110 to 1350 pg m(-3), while dissolved water concentrations were between 420 and 1650 pg L(-1). Shallow slopes of log Koc vs. log Kow plots indicated a colloidal contribution to the apparent dissolved-phase concentrations, such that a three-phase partitioning model was applied. Fugacity ratios for individual congeners were calculated under the most conservative assumptions, and their values (log-transformed) were examined via a single-sample T-test to determine whether they were significantly less than 1 at the 95% confidence level. This method demonstrated that air-water exchange resulted in net volatilization in all zones over all cruises for all but seven high molecular weight congeners. Calculated net fluxes ranged from +360 to +3000 ng m(-2) d(-1) for sigma PCBs. The colloidal correction decreased the volatilization flux of sigma PCBs by approximately 30%. The decachlorinated congener (PCB 209), exhibited unusually high concentrations in the suspended solids, especially in the southern portions of the river, indicating that there is a distinct source of PCB 209 in the Delaware River.

PBDEs, PCBs and PCDD/Fs in the sediments from seven major river basins in China: Occurrence, congener profile and spatial tendency

“…However, CB-209 was comprised <1% of the PCBs in most of the commercial Aroclors except Aroclor 1268 (Kannan et al, 1997). Rowe et al (2007) observed higher level of CB-209 in the suspended solids of Delaware River, and one possible source is a titanium dioxide purification plant that is located on the lower Delaware. In the present study, field investigation indicated S2 and S3 sites could be affected by some industrial cities, e.g., Lvliang City, Yulin City and Baotou City, where coal chemical industry, metallurgy, rareearth (RE), manufacturing were extensively developed.…”

Air–water exchange of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) at a coastal site in Izmir Bay, Turkey

“…In New York-New Jersey Harbor, higher dissolved-phase PCB concentrations were measured with a maximum value of 4160 pg L − 1 (Totten et al, 2001). In Delaware River, the highest value of dissolved and particle phase PCB concentrations were 1700 and 4900 pg L − 1 , respectively (Rowe et al, 2007).…”

China's water pollution by persistent organic pollutants

“…This corresponds with the heavy industrial presence in North China compared to South China. The levels of PCBs in the Haihe, Huaihe and Tonghui Rivers were higher than those in the Houston Ship Channel, USA (0.49e12.5 ng/L) (Howell et al, 2008), Ebro River in Spain (43.2e108 ng/L) (Gómez-Gutiérrez et al, 2006), Mississippi River (22.2e163 ng/L) and Delaware River (0.42e1.65 ng/L) (Rowe et al, 2007) (Table S2), suggesting that PCB contamination in these rivers are at the high end of the global range.…”