Heavy Metal Contamination and Distribution in the Urban Environment of Guangzhou, SE China

Ever-increasing heavy metal accumulation in the urban environment of Guangzhou, the largest light industrial production base and one of the most rapidly developing cities in China, poses a serious threat to environment as well as to human health in the region. As a sink or source, urban deposits are good indicators of the level and extent of heavy metal accumulation in the surface environment. The aim of this preliminary study was to examine the distribution of heavy metal contamination in the urban environment of Guangzhou. It was based on a systematic sampling of road dusts and corresponding gully sediments along major roads running mainly through commercial and residential to industrial districts of the city. In addition to road dusts and gully sediments, ceiling dusts from the Pearl River Tunnel were also collected to characterize anthropogenic emissions dominated by traffic-related activities. In general, the level of Cd, Cu, Pb and Zn contaminations were more severe on the industrialized side of Guangzhou than on the western side where heavy traffic and industrial activities were limited. The primary determinants of the level of heavy metal contamination and the distribution of this contamination in the urban environment of Guangzhou were the site-specific conditions of its urban setting, particularly the types of industries, the nature of the traffic flow, sample residence times and variations in grain size of the particulate contaminants. This study highlights the complexity of the urban system and indicates that in just such a system individual urban components should be interlinked to assess the long-term environmental and health effects of heavy metal contamination. Among the heavy metals tested – Cd, Cu, Pb and Zn – the level of Zn contamination was the most severe and widespread, and thus requires immediate attention.     

The effects of walnut and pine leaves on bread wheat growth and frequence of common weed species in the East-Mediterranean region

A field experiment was carried out to determine the effects of walnut (Juglans regia L.) and pine (Pinus sp.) leaves on bread wheat (Triticum aestivum L.) growth and weed control, during 2001-02 and 2002-03 growing seasons in East Mediterranean region of Turkey. In this research, the treatments were: applications of ground walnut leaves (GWL) and ground pine leaves (GPL) at 19 g/m2 dose at Zadoks-11, applications of 200, 400 and 800 cc/m2 of walnut leaves extract (WLE2, WLE4 and WLE8 respectively), pine leaves extract (PLE2, PLE4 and PLE8 respectively), mixture extract of 200 cc walnut and 200 cc pine (ME), herbicide application (HA) at 8 g/m2 dose at Zadoks-21, and control (C) without any treatment. The results have indicated that the effects of treatments were significant for grain yield (GY), plant height (PH), flag leaf length (FLL), weed number per square meter (WN), but non significant for grain number per head (GN), grain weight per head (GW), 1000 grain weight (1000 GW), flag leaf width (FLW), head number per square meter (HN), vegetative period (VP), grain filling period (GFP) and days to maturity (DM).     

A Novel Stochastic Optimization Model for Reverse Logistics Network Design of End-of-Life Vehicles: A Case Study of Istanbul

Environmental Modeling & Assessment - Waste management is gaining crucial importance as recycling aims at transforming produced waste into value for the economy. As the automotive industry is...