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ENVIRONMENTAL MONITORING OF DIOXIN LIKE COMPOUNDS IN THE UNITED STATES. Commission for Environmental Cooperation of North America Fourth Workshop on Sources and Measurements of Dioxins, Furans and Hexachlorobenzene October 28-29, 2010. Dwain Winters Winters Environmental
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ENVIRONMENTAL MONITORING OF DIOXIN LIKE COMPOUNDS IN THE UNITED STATES Commission for Environmental Cooperation of North America Fourth Workshop on Sources and Measurements of Dioxins, Furans and Hexachlorobenzene October 28-29, 2010 Dwain Winters Winters Environmental Bethesda, Maryland
CRITICAL AREAS FOR ENVIRONMENTAL MONITORING • DIOXIN IN LAKE SEDIMENT • DIOXIN IN AMBIANT AIR • DIOXIN IN SOIL
NATIONAL DIOXIN AIR MONITORING NETWORK(NDAMN) • A nationally based ambient air monitoring network • The target analytes are vapor and particulate phases of dioxin-like compounds • 32 stations operated in rural and non-impacted sites • Network started in 1999 and ended in 2004
WHY WAS NDAMN CREATED? • Establishing background levels • Determining temporal and geographical variability • Investigating long-range transport and transboundary movement • Verify/calibrating EPA’s air models • Providing data to determine exposures \
Locations of NDAMN Stations = Rural Site = Remote Site
Dioxin Air Sampler Quartz Fiber Filter for particle bound dioxin PUF plug for vapor-phase dioxin
Sampling Frame Sampling period: • 24 hrs/d; 7 d/wk • 28 days All stations operate simultaneously with 4 sampling periods/year
(S) Summer (W) Winter Year Season Site General increase observed in CDD/F TEQ in Late Fall/ Early Winter vs Summer
NDAMN 2001 Population Density 2000 COMPARING 2001 RESULTS WITH POPULATION DENSITY
General Observations for NDAMN from 1999 - 2001 • The dominant CDD/F congeners in ambient air were the OCDD>1,2,3,4,6,7,8-HpCDD> 1,2,3,4,6,7,8-HpCDF> OCDF. • This profile was constant over all NDAMN sites. • The 1,2,3,7,8-PCDD contributes over 40% of the dioxin TEQ.
General Observations for NDAMN from 1999 – 2001, continued • PCB-118 dominates coplanar PCBs in ambient air followed by PCB-105, PCB-77 and PCB-156. • PCB-126 dominates the TEQ.
NDAMN conclusions • 22 rural sites: • Annual mean dioxin TEQ (WHO method) air concentrations • Range: 2 fg m3 to 28 fg/ m3; • Overall mean: 12 fg m3. • Mean annual PCB TEQ air concentrations • Range: 0.15 – 9 fg/ m3. • Overall mean: 1 fg/ m3. • These values are consistent with other studies of rural areas.
NDAMN CONCLUSIONS, continued • 8 Remote Sites • Annual mean dioxin TEQ (WHO method) air concentrations • Range: 0.5 to 3 fg/ m3 • Overall mean: 1.05 fg/ m3 • Mean annual PCB TEQ air concentrations • Range: 0.05 – 1.0 fg/ m3 • Overall mean: 0.23 fg/ m3
NDAMN CONCLUSIONS, continued • Dioxin concentrations at remote sites were on average one order of magnitude lower than what was measured at rural sites. • Although not statistically significant, PCBs were approximately 5-times lower in remote sites as compared to rural sites.
NDAMN CONCLUSIONS, continued • CDDs and CDFs air concentrations have generally remained about the same from 1999 – 2001 when all NDAMN locations are considered. • CDD and CDF air concentrations have decreased from 1999 to 2001 at a few specific locations.
NATIONAL DIOXIN SOIL SURVEY NDAMN air sampling stations. Circles indicate stations included in soil survey and triangles are excluded stations.