Heavy metal contamination in soil alongside mountain railway in Sichuan, China

Wang

Science of The Total Environment

et al. 2015

137

• Cr, Zn, Cu, As, Cd, and Pb in soils along the highway are related to the traffic.• There are three distribution patterns of the traffic-related metals in soils.• Regional differences had significant relationship with the enrichment levels.• Cd was the prior metal and the TTH was the key area for soil environment monitoring. The road transportation could affect roadside soils environment detrimentally, including heavy metal enrichment. In order to identify and evaluate the enrichment of heavy metals resulted from road transportation on the Tibetan Plateau, the 11 heavy metals (V, Cr, Co, Ni, Cu, Zn, As, Cd, Rb, Pb and Tl) in the topsoil (0-10 cm depth) from four sites along the Qinghai-Tibet highway were discussed in this study. Our results indicate that heavy metals such as Cr, Cu, Zn, As, Cd and Pb are related to road transportation. The content of most of these heavy metals in roadside soils decreased exponentially with the distance from the road, as did some of the Nemero Synthesis Indexes (PN values). The contamination factor for the traffic-related metals ranged from 0.56 (no pollution) to 5.67 (considerable pollution) and the Nemero Synthesis Indexes of these heavy metals ranged from 0.80 (no pollution) to 4.49 (severe pollution). Cd was of priority concern as it had the highest contamination factor. The highest PN value for these traffic-related heavy metals was found in soils at site TTH (alpine steppe). Although transportation contributed to the high contents of these traffic-related metals in roadside environments, regional differences such as wind and the terrain also had significant relationship with their enrichment in these roadside soils. The roadside distance at which there is a potential risk to livestock and wildlife from the contamination of soils by heavy metals should be determined scientifically along the Qinghai-Tibet highway, based on the different natural environments found in the region. a b s t r a c t a r t i c l e i n f o

Section: Relationship Between Heavy-metal Contents In Roadside Soils supporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Identification of traffic-related metals and the effects of different environments on their enrichment in roadside soils along the Qinghai–Tibet highway

Wang

Science of The Total Environment

et al. 2015

137

“…Chinese investigators (Liu et al, 2009) studied heavy metal concentration in soil within the vicinity of mountain railway in Sichuan. Cu, Mn, Cd and Zn concentrations were elevated in top soil in the railway surroundings, whilst Pb showed no significantly raised level.…”

Section: Contaminationmentioning

confidence: 99%

Railway Tracks - Habitat Conditions, Contamination, Floristic Settlement - A Review

Galera

Sudnik‐Wójcikowska²

2012

ENRR

Apart from roads, railways are one of the principal means of transportation. The specificity of rail transportation causes some environmental problems. The study presents a review of the major environmental problems connected with railway transportation. The construction of railway tracks and properties of used materials, as well as the maintenance of railway infrastructure are responsible for the specific habitat condition with alkaline soil reaction and varying but rather high levels of nutrients, which favour plant encroachment and growth. The results of investigations described in this study show clearly that railway transportation causes typical organic and inorganic contamination. Among the most important railway pollutants are polycyclic aromatic hydrocarbons, heavy metals, and to some extent, polychlorinated biphenyls. The study also presents some information about the progress of floristic studies in operating and abandoned railway lines. In addition some trends in the transformation of the flora in abandoned railway areas are discussed: the retreat of alien species with a short life cycle, the encroachment of native perennial plants and an increase in the number of trees.

“…The study of traffic-related metals in roadside soils along the Qinghai-Tibet highway indicated that Cu, Zn, Pb, Cr, Cd, and As were related to road transportation (Zhang et al 2015) and the contents of Zn, Pb, and Cd in roadside soils decreased exponentially with the distance from the road (Yan et al 2013;Zhang et al 2015). The heavy metal in soil alongside mountain railway in Sichuan showed that the concentrations of Cu, Zn, Mn, Pb, and Cd decreased with increasing distance from the railroad and indicated that railway transport was the source of such pollutants (Liu et al 2009 The third group of metals, Hg and As, indicated that the traffic did not affect both of elements because in this study area, the concentration of Hg and As did not decrease with increasing distance from the highway. It is generally believed that the coal combustion and solid waste incineration and wastewater discharge were generally regarded as the main pollution resource of Hg and As.…”

Section: Discussionmentioning

confidence: 99%

Highway increases concentrations of toxic metals in giant panda habitat

Zheng

Chen

Maltby

et al. 2016

Environ Sci Pollut Res

The Qinling panda subspecies (Ailuropoda melanoleuca qinlingensis) is highly endangered with fewer than 350 individuals inhabiting the Qinling Mountains. Previous studies have indicated that giant pandas are exposed to heavy metals, and a possible source is vehicle emission. The concentrations of Cu, Zn, Mn, Pb, Cr, Ni, Cd, Hg, and As in soil samples collected from sites along a major highway bisecting the panda's habitat were analyzed to investigate whether the highway was an important source of metal contamination. There were 11 sites along a 30-km stretch of the 108th National Highway, and at each site, soil samples were taken at four distances from the highway (0, 50, 100, and 300 m) and at three soil depths (0, 5, 10 cm). Concentrations of all metals except As exceeded background levels, and concentrations of Cu, Zn, Mn, Pb, and Cd decreased significantly with increasing distance from the highway. Geo-accumulation index indicated that topsoil next to the highway was moderately contaminated with Pb and Zn, whereas topsoil up to 300 m away from the highway was extremely contaminated with Cd. The potential ecological risk index demonstrated that this area was in a high degree of ecological hazards, which were also due to serious Cd contamination. And, the hazard quotient indicated that Cd, Pb, and Mn especially Cd could pose the health risk to giant pandas. Multivariate analyses demonstrated that the highway was the main source of Cd, Pb, and Zn and also put some influence on Mn. The study has confirmed that traffic does contaminate roadside soils and poses a potential threat to the health of pandas. This should not be ignored when the conservation and management of pandas is considered.