Submitted to: Journal of Environmental Science and Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/23/2006
Publication Date: 2/21/2006
Citation: Goel, A., Mcconnell, L.L., Torrents, A., Scudlark, J.R., Simonich, S. 2006. Spray irrigation of treated municipal wastewater as a potential source of atmospheric pbdes. Journal of Environmental Science and Technology. 40(7):2142-2148. Interpretive Summary: Spray irrigation of wastewater effluent is a common discharge practice in Delaware and Maryland counties on the eastern shore of the Chesapeake Bay. Municipal wastewater effluent is known to contain flame retardants, polybrominated diphenyl ethers (PBDEs) which can be released to the atmosphere during the spraying process or from the soils on which the wastewater is applied. These chemicals are possible endocrine disruptors and as such their occurrence in the atmosphere is a matter of concern. However, information on the occurrence of these compounds in the atmosphere of the Delmarva Peninsula and the trends in concentrations over time is not available. From 2001-2003, 240 samples of air were collected (mainly April to September) from three sites on the Delmarva Peninsula. These samples were analyzed for several of the PBDEs which are most commonly reported in the environment. These PBDEs were present in 75% samples. The average total PBDE concentrations at two of the sites represent regional background levels. However, the third site, which is about 6 km distant from the largest spray irrigation facility on the Peninsula, showed elevated levels of PBDEs in the air. Concentrations at this site were 5-10 times higher than at the other two sites and were significantly correlated with temperature, indicating local source(s). 48-h back trajectory analyses for the three sites indicate that the concentrations increase as the air mass travels over the Peninsula, suggesting that spray irrigation operations in the region are impacting the air concentrations at the third site. The aerial concentrations of PBDEs in the Peninsula are also increasing at an exponential rate; the atmospheric doubling times for the different PBDEs range from 1.1-1.7 yrs.
Technical Abstract: Air concentrations of four Penta-BDE congeners (47, 99, 199 and 154) were monitored at three remote/rural locations on the mid-Delmarva Peninsula. High volume air samplers were utilized to collect 24-h weekly air samples (n=240, 2001-2003). PBDEs were present in 75% samples and the congener detection frequency in gaseous phase followed the pattern 99>47>100>154. PBDEs occurred predominantly in the gas phase phase. The average gas-phase concentrations at two of the sites (BDE 47: 10-19 pg/m3; BDE-99: 5.4-6.6 pg/m3) are comparable to those observed in rural Canada (BDE-47: 4.6 pg/m3; BDE-99: 4.3 pg/m3), suggesting that these sites reflect background levels. PBDE concentrations at the third location were up to 5-10 times higher (total PBDEmax= 910 pg/m3) and were significantly correlated (p<0.0001) with temperature indicating local source(s). 48-h back trajectory analysis for the three sites suggests that the concentrations increase as the air mass travels over the Peninsula. Spray irrigation of treated municipal wastewater, a common practice for the counties on the Delmarva Peninsula, is suspected to be a source of PBDEs at the third location. Several spray irrigation facilities are located to the south and west of this site, the general wind direction during the spring and summer time when most of our samples were collected. The aerial concentrations of PBDEs in the Peninsula are also increasing at an exponential rate; the atmospheric doubling times for the different congeners range from 1.1-1.7 yrs.