Sources, distribution and variability of airborne trace metals in La Plata City area, Argentina

• Published in: Environmental pollution (1987) Vol. 111; no. 1; pp. 149 - 158
• Main Authors: Bilos, C, Colombo, J.C, Skorupka, C.N, Rodriguez Presa, M.J
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-01-2001; Elsevier
• Subjects: Air Pollutants - analysis; Air pollution; Airborne particulate matter; Applied sciences; Argentina; Argentina, La Plata; Atmospheric pollution; Enrichment factors; Environmental Monitoring - methods; Exact sciences and technology; Heavy metals; Humans; Metals, Heavy - analysis; Pollution; Pollution sources. Measurement results; Urban air quality; Urban Health; South America; Argentina; America; Urban air quality; Air pollution; Airborne particulate matter; Enrichment factors; Heavy metals; Natural origin pollution; Statistical analysis; Air content; Annual variation; Air quality; Urban area; Diurnal variation; Spatial variation; Variance analysis; Time variation; Heavy metal; Suspended particle; Surveillance; Seasonal variation; Aerosols; Pollution source inventory; Nocturnal variation; Anthropogenic factor
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/S0269-7491(99)00328-0

“Capsule”:
Exhaust from vehicles appeared to be the major source of metal aerosols in the La Plata, Argentina region.
Airborne particulate trace metals have been measured bimonthly during day and night hours in four permanent stations located in residential, industrial and commercial sectors of La Plata City region, to characterize the sources and variability of atmospheric inputs. Airborne trace metal regional averages (Pb 64±62, Cu 30±27, Mn 26±20, Zn 273±227, Fe 1183±838, Ca 5343±3614, Mg 1472±967, Cr 4.3±2.4, Ni 3.2±3.5 and Cd 0.41±0.42 ng/m
3) are comparable to the values reported for not grossly polluted cities and below the general trend described for urban particulates. Two- and three-way analysis of variance and variance components tests (
P<0.05) were performed to assess the contribution of the diurnal (day vs. night), spatial (inter-station) and temporal (inter-month) components of variability. Trace metal concentrations followed the behavior of total suspended particles with higher concentrations during the day and at the Downtown station and lower at the Residential site. In general, spatial and temporal variations prevailed over diurnal differences. Spatial differences were clearly most significant for Pb, which presented higher values at the Downtown site reflecting the importance of motor exhaust inputs. In contrast, diurnal differences were more important for Mn due to increased dust resuspension during day hours. A seasonal trend with concentrations usually increasing during winter months and decreasing in spring–summer was also detected. Enrichment factors (EF) were calculated to evaluate anthropogenic versus natural element sources. High EF (21–376) were obtained for Pb, Zn, Cd and Cu reflecting the importance of anthropic inputs. The comparison with EF calculated for high-emitting vehicle particle emissions indicated that motor exhausts are the most important source of these elements in La Plata region. In contrast, the EF calculated for Mn, Cr, Ni, Ca and Mg were low (1.3–7.5) suggesting chiefly natural sources, i.e. soil-derived dusts.