Highway increases concentrations of toxic metals in giant panda habitat

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

Socio-economic benefits of leaded gasoline phase-out: the case of Lebanon

Lead emissions from vehicles using leaded gasoline is a serious environmental problem in urban areas. While leaded gasoline has been completely phased out in many developed countries, it is still the predominant fuel grade in most developing countries. This paper presents an estimation of the health and economic benefits and costs of the transition from leaded to unleaded gasoline in Lebanon based on relevant dose-response functions and available country-specific data. Comparing the potential costs of the phase-out and the predicted benefits, it was concluded that such action is economically highly justifie

Impacts of traffic-induced lead emissions on air, soil and blood lead levels in Beirut

Lead is a purely toxic heavy metal which induces a wide variety of adverse physiologic effects. Nevertheless, it has been mined and used for more than 8,000 years. Among the different contemporary sources of lead pollution, traffic-induced emissions from the combustion of leaded gasoline is of particular concern, as it can constitute more than 90 percent of total lead emissions into the atmosphere in congested urban areas where no phase-out activities have been adopted. Gasoline lead content and traffic volume are strongly correlated with concentrations of lead in various environmental media. In the absence of policies to reduce the use of lead in gasoline or to favor the use of unleaded gasoline, leaded gasoline remains the predominant grade in many countries. This paper assesses the status of lead pollution from the combustion of leaded gasoline in Beirut based on field measurements of lead in air and roadside dust of urban and rural/suburban areas and recent data on soil and blood lead levels. Average atmospheric lead concentrations was about 1.86 ugm -3 at urban locations and 0.147 umg -3 at suburban locations. The analysis of roadside dust revealed an average lead level of 353 ugg -1 along urban streets and 125 ugg-1 along rural/suburban roadsBlood lead levels were also relatively high in comparison to countries where leaded gasoline has been phased-out

Vehicular emissions in roadway tunnels: a critical review

Traffic-induced emissions are a major source of air pollutants, particularly in urban areas. Adequate characterization and quantification of the contribution of this source depend to a large extent on the use of reliable pollutant emission factors. Recently, in addition to characterizing vehicle-induced pollutants, tunnels have been used to evaluate on-road emission factors. Accurate determination of those factors depends on the reliability of field measurements and the use of appropriate mathematical models to simulate the behavior of pollutants inside a tunnel. Different models, with various degrees of complexity, have been developed to estimate vehicle emission factors, and to simulate the fate and transport of pollutant emissions in tunnels. This article presents a critical review of research work conducted to characterize and simulate vehicle-induced pollutants in tunnels. Air-quality standards in tunnels, tunnel ventilation, and factors affecting pollutant concentration in tunnels with corresponding control measures are first addressed. Limitations and research needs are discussed in the context of the current state of the art in tunnel air-quality modeling

Vehicular emissions and air quality assessment in roadway tunnels: The Salim Slam tunnel

Vehicle emissions constitute a serious environmental concern particularly in confined spaces such as tunnels and underground parking garages. These emissions are characterized with the presence of various pollutants, which, at high concentrations, can cause adverse health effects. This paper presents an assessment of vehicle-induced emissions and air quality in a heavily traveled tunnel located in urban metropolitan Beirut. For this purpose, common modeling theories were reviewed, relevant air quality standards were defined, existing conditions were characterized, an air-sampling program was implemented, and mathematical modeling to simulate field measurements was conducted. Impact significance was evaluated by comparing measured and simulated pollutant concentrations with air quality standards. Model simulations were also used to evaluate vehicle-induced pollutant emission factors. Finally, mitigation measures are proposed to insure proper air quality management inside the tunnel.<br/

Air quality assessment in tunnels: field measurements and mathematical modeling

As a result of increased emissions and inadequate ventilation, the concentration of these pollutants in confined spaces such as tunnels can result in deleterious impacts on health and the well being of exposed population.The large difference in pollutant concentrations between the inside and outside of a tunnel has been used to derive on-road emission factors.This paper assesses vehicle-induced emissions and air quality inside a heavily traveled tunnel in an urban are

A case study on the economic benefits of reducing emissions from the cement industry

The cement industry constitutes a major source of air pollution and its impacts have historically raised considerable public concern.In Lebanon, the town of Chekka, which is the site of several cement factories accounting for more than 60 percent of the country's cement production, air pollution has been the subject of long-lived controversy with respect to emissions and potential adverse health and environmental impacts.This paper describes an air quality assessment study conducted to shed light on the extent and nature of the impact of the cement industry on its immediate vicinity.<br/