Skip to main content
U.S. flag

An official website of the United States government

Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean

April 22, 2014

Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9–126 ng/m3 (mean = 25 ± 34) at source and 0.05–0.71 ng/m3 (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1–3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses.

Publication Year 2014
Title Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean
DOI 10.1016/j.scitotenv.2013.08.076
Authors Virginia H. Garrison, Michael S. Majewski, William T. Foreman, Susan A. Genualdi, Azad Mohammed, Stacy L. Massey Simonich
Publication Type Article
Publication Subtype Journal Article
Series Title Science of the Total Environment
Index ID 70102296
Record Source USGS Publications Warehouse
USGS Organization Southeast Ecological Science Center