Grantee Research Project Results
2002 Progress Report: Atmospheric Dry Particle Deposition of POPs and Trace Metals in an Urban- and Industrially-Impacted Mid-Atlantic Estuary (AEOLOS B Mid-Atlantic)
EPA Grant Number: R828177Title: Atmospheric Dry Particle Deposition of POPs and Trace Metals in an Urban- and Industrially-Impacted Mid-Atlantic Estuary (AEOLOS B Mid-Atlantic)
Investigators: Eisenreich, Steven J. , Totten, Lisa A. , Holsen, Thomas M.
Current Investigators: Totten, Lisa A. , Eisenreich, Steven J. , Holsen, Thomas M.
Institution: Rutgers
EPA Project Officer: Hahn, Intaek
Project Period: August 1, 2000 through July 31, 2002 (Extended to July 31, 2004)
Project Period Covered by this Report: August 1, 2001 through July 31, 2002
Project Amount: $230,000
RFA: Exploratory Research - Engineering, Chemistry, and Physics) (1999) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Air , Safer Chemicals
Objective:
The objectives of this research project are to: (1) determine the dry depositional flux of coarse and fine particles, selected Persistent Organic Pollutants (POPs), and trace metals to the lower Hudson River Estuary (HRE) using surrogate depositional surfaces; (2) determine the seasonal particle-size distribution of mass, selected POPs, and trace metals in the lower HRE; (3) model the dry particle depositional fluxes of particle mass, selected POPs, and trace metals to the HRE based on the particle size distribution; (4) provide a field evaluation of the surrogate surface and models to estimate dry particle depositional fluxes; and (5) provide an assessment of the dry depositional component of the atmospheric deposition of selected POPs and trace metals to the lower HRE.
Progress Summary:
Five field experiments were conducted from June to August 2001, to: (1) test the operation of an automated dry deposition collector (MIC-B dry-wet); (2) estimate the dry deposition mass fluxes at the New Brunswick site; (3) compare different depositional media and choose appropriate media for total mass, trace metals, and organic compounds; and (4) determine the appropriate deployment time for intensive field campaigns. Two integrating MIC-B wet-only collectors were purchased and sent to Clarkson University, where they were converted into automated dry-wet deposition collectors. They then were returned to Rutgers, where they have been undergoing field testing and calibration.
After the completion of testing and calibration, long-term sampling was conducted at both the Jersey City (JC) and New Brunswick (NB) locations for 1 year starting on August 15, 2001. Samples were deployed continuously for 12-day periods. Three types of fluxes were measured: mass, polychlorinated biphenyl (PCB), and polycyclic aromatic hydrocarbon (PAH).
Higher mass fluxes were observed at JC compared to NB, although the magnitude of the difference depends on the type of media used to sample particles. Quartz fiber filters (QFFs) are as efficient as greased strips in capturing particles at NB, but not at JC. This difference may be due to the saturation of particle loadings on QFFs during the 12-day sampling period because of the high particle concentrations at JC. QFFs were used to measure PCB and PAH fluxes. Thirty-four PAHs were analyzed, including phenanthrene (chosen for its high atmospheric concentrations), pyrene (chosen for its health-related nature as an irritant), and benzo[a]pyrene (chosen due to its specific mention as a U.S. Environmental Protection Agency Primary Pollutant of concern due to its carcinogenic nature). Comparing the PAH profiles of NB and JC for the same sampling dates, we find r2 values as high as 0.95 and P-values less than 10-10. This strongly indicates that both sites have similar sources of PAHs, although the fluxes generally were higher at JC. The fluxes obtained during long-term sampling are directly measured fluxes (PCB mass divided by deposition area and deploy time). The lower molecular weight PAHs were observed to have higher fluxes than the higher molecular weight PAHs. These results indicate that the influence of the total atmospheric concentration can be observed in the particle flux to the surrogate surface, even though the lower molecular weight compounds are mostly in the gas phase (i.e., not bound to aerosols).
The relatively small fraction of particle-bound low molecular weight PAHs appear to have significant contributions to the total PAH mass flux. The fluxes may be compared with modeled fluxes from the New Jersey Atmospheric Deposition Network (NJADN), which are calculated from the product of average PCB concentrations of particulate samples (collected by using a Hi-Volume air sampler) and an assumed average particle deposition velocity of 0.5 cm s-1. The PAH fluxes measured in this work are 2.6 and 3.1 times higher than the estimates from NJADN data for JC and NB sites, respectively. This suggests that the assumed deposition velocity (Vd) of 0.5 cm s-1 may not be too low. Vd was computed for each season using the ratio of the measured flux to the average particle-phase concentration measured as part of the NJADN. Lowest deposition velocities were most often calculated from the winter data. This effect may arise from the lower vapor pressures exhibited by these compounds at lower temperatures. Plotting the calculated deposition velocity versus the log of the vapor pressure for each compound similarly reveals that lower vapor pressures lead to smaller deposition velocities. Annual average Vd ranged from about 5 to about 0.2 cm/s for the PAHs. Gas absorption is a significant contributor to deposition flux for the low molecular weight PAHs.
The PCB fluxes at JC typically are higher than those at NB, although the difference is small. The homolog distribution of the average flux is slightly different at each site, reflecting differences in the congener pattern observed at each site. Our results show that the measured and the modeled NJADN fluxes are quite similar for the JC site, but at NB, the measured fluxes are on average 2.8 times the modeled fluxes. This suggests that the deposition velocity of 0.5 cm/s-1 is a good estimate in calculating the deposition fluxes at JC, and possibly at other urban areas, when the actual particle size distribution cannot be measured or is not available. The higher fluxes at NB could be due to larger mass median diameter of particles at this site.
Year 1 of the project was dedicated to: (1) purchasing and testing of the MIC-B wet-only integrating samples and converting them to automated dry and wet collectors according to the design given above; and (2) the continued measurement of PCBs and PAHs in the ambient atmosphere to provide a continuous measurement framework for the dry deposition measurements. The continuous dry deposition measurements were initiated on August 15, 2001, at the NB and JC sites and ended on August 15, 2002. All long-term samples now have been analyzed for 80 PCB congeners, 34 PAH compounds, and 16 trace metals. In addition, several major field intensive campaigns were conducted, in which several other collection devices and strategies were deployed along with the continuous dry deposition collectors. Approximately 150 samples were collected on various media during these intensive campaigns.
Future Activities:
The final year of the project will be devoted to chemical analysis of the approximately 150 samples that were collected during the field campaigns. We also will perform a thorough quality assurance evaluation of all data (including blank corrections, gas absorption analysis, calculation of final detection limits), and write the final report.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
Northeast, Atlantic coast, environmental chemistry, chemicals, toxics, particulates, atmosphere, chemical transport, estuary, mid-Atlantic, EPA Region 2., Scientific Discipline, Air, Toxics, Water, Geographic Area, Environmental Chemistry, HAPS, State, Air Deposition, Environmental Monitoring, Mid-Atlantic, Engineering, Chemistry, & Physics, Great Lakes, EPA Region, dry deposition studies, particle size, particulates, receptor accumulation rates, estuaries, PCBs, industrial emissions, Hudson River Estuary, toxic metals, New Jersey (NJ), gaseous organic compound, meterology, Lake Michigan, Region 2, atmospheric deposition, coastal ecosytems, persistant organic pollutantsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.