Effect of Non-Vehicular Sources on Heavy Metal Concentrations of Roadside Soils

Abstract

Soils along highway environments typically contain high concentrations of heavy metals because of non-point contamination sources, most commonly vehicle exhaust and wear of vehicle parts. Pb, Zn, Cu, Cr, Sb, Ba and Ra concentrations of soils along roadways with very low traffic volumes in a rural portion of San Patricio County, Texas, have been studied in order to distinguish the effects of a point source (an industrial waste landfill) from the effects of traffic. The highest concentrations of Zn, Cr, Sb, Ba and Ra were detected in soils along the access road to the landfill. The association of high Ba values with high Ra values suggests that the most probable sources of this contamination were oilfield waste from storage tank bottoms, which were disposed of in landfill waste pits and were also spread over roads within the landfill to decrease dust. Outside the landfill along a different roadway, a second contamination area which was characterized by very high Ba but low Sb and Ra concentrations compared to background values, has been detected. Drilling mud spill is the most probable source of this contamination.The contaminations caused by these two point sources differ from typical vehicle-sourced contamination in two ways: their areal extent was limited and contaminants were not typical for highway environments (like Ba and Ra). Like vehicular contamination, however, these areas were confined to the immediate vicinity of the roadways. Another difference is that Pb in most vehicle-contaminated areas is strongly bound to the soil constituents, mostly organic matter, whereas the point source Pb was found to be readily exchangeable and to have no association with organic matter.

Forest soils adjacent to urban interstates: Soil physical and chemical properties, heavy metals, disturbance legacies, and relationships with woody vegetation

“…One of the highest levels of chromium observed in a plot (1516 S) occurred next to the county landfill. Another study also showed that the highest chromium levels were observed on the access road to an industrial waste landfill (Turer 2005).…”

Heavy Metals Accumulation In Roadside Soil And Vegetation Along A Major Highway In Libya

“…Many investigations in recent years have concentrated on the pollution of roadside soil and vegetation by lead from motor vehicles originating from the use of additives in petrol (Cannon and Bowles, 1962;Chow, 1970;Motto et al, 1970;Page and Ganje, 1970;Ward et al, 1974;Ward et al, 1975;Iqbal and Qadir, 1990;Clarke, 1994;Morton-Bermea et al, 2002;Bhargava et al, 2003;Turer, 2005). Tetra-alkyl lead is usually added to petrol at a rate of about 0.9 g Pb L -1 (Atkins, 1969), most of which gets emitted from the exhausts of motor vehicles (Clark, 1994) and eventually get deposited.…”

“…For vegetation the levels were Pb,350;Cu,30;Ni,3.7 and Cr,4. The possible hazards arising from pollution of the environment by heavy metals have surfaced more recently, and the toxicity of some of these metals toward humans especially children when exposed to them from the atmosphere, water or food has been well documented (Browning, 1969;World Health Organisation, 1972;Page and Bingham, 1973;Mahaffey, 1977;Smith, 1994). Vehicle exhausts, as well as several industrial activities, emit these heavy metals (Lagerwerff and Specht, 1970;Solomon and Hartford, 1976;Bower et al, 1978;Reeves and Brooks, 1983;Turer, 2005;Guan Dong-sheng and Pert, 2006) so that soils, plants and residents along roads with heavy traffic loads are subjected to increasing levels of contamination with heavy metals (Welch and Dick, 1975;Harve and Underdal, 1976;Ward et al, 1977;Harrison et al, 1981;Ho and Tai, 1988;Jaradat and Moman, 1999;Delmas et al, 2002;Bhargava and Gupta, 2003) Although substantial work has been carried out in Europe and the United States on lead distribution with distance from roads, and the trends expected are well established, so far as we are aware data for other metals is more restricted, and there are no previous studies of this type from Libya.…”

Trace Metal Concentrations in Pleurozium Schreberi and Taraxacum Officinale Along the Road No. 7

“…Traffic-related metals introduced into the environment derive from many different sources of emissions, including vehicular: tires, brake and clutch linings, car bodies, motor parts, fuel additives, lubricants [4,5] and non-vehicular sources: road pavement and embankment, roadside screens, de-icing substances [6][7][8]. Folkeson et al [9] identify the following sources of road pollution: traffic and cargo, pavement and embankment materials, road equipment, maintenance and operation and external sources.…”

“…Roadside pollution depends on many factors, i.e. : distance to the road, traffic density, road profile and also on environmental factors including: topography of adjacent area [3,7,[12][13][14], land cover [8] and meteorological factors including precipitation, wind speed and wind direction [12,13,15].…”