Seasonal variation of heavy metals in ambient air and precipitation at a single site in Washington, DC.
Atmospheric samples of precipitation and ambient air were collected at a single site in Washington, DC, for 7 months (for ambient air samples) and 1 year (for wet deposition samples) and analyzed for arsenic, cadmium, chromium and lead. The ranges of heavy metal concentrations for 6-day wet deposition samples collected over the 1-year period were 0.20-1.3 microg/l, 0.060-5.1 microg/l, 0.062-4.6 microg/l and 0.11-3.2 microg/l for arsenic, cadmium, chromium and lead, respectively, with a precision better than 5% for more than 95% of the measurements. The ranges of heavy metal concentrations for the 6-day ambient air samples were 0.800-15.7 ng/m(3), 1.50-30.0 ng/m(3), 16.8-112 ng/m(3), and 2.90-137 ng/m(3) for arsenic, cadmium, chromium and lead, respectively, with a precision better than 10%. The spread in the heavy metal concentration over the observation period suggests a high seasonal variability for heavy metal content in both ambient air and wet deposition samples.
Melaku
Samuel
S
Department of Chemistry, Howard University, 525 College Street, NW Washington, DC 20059, USA. samuelmelaku@yahoo.com
Morris
Vernon
V
Raghavan
Dharmaraj
D
Hosten
Charles
C
D000393:Air Pollutants / Q000032:analysis; D001151:Arsenic / Q000032:analysis; D002104:Cadmium / Q000032:analysis; D011232:Chemical Precipitation; D002857:Chromium / Q000032:analysis; D002947:Cities; D004219:District of Columbia; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis*; D007854:Lead / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis
D000393:Air Pollutants; D004785:Environmental Pollutants; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; D002857:Chromium; D007854:Lead; D001151:Arsenic