Wanliu and Xiaowangzhuang transects which operated in 1994 and 2001 respectively along Zhengzhou-Shangqiu section on Lianyungang-Horgas highway were chosen to investigate heavy metal (Cd, Cu, Pb, Zn, Ni, and Cr) pollution and potential ecological risks of roadside soils. Concentrations of soil heavy metals on Wanliu transect were higher than that on Xiaowangzhuang transect. The content of soil heavy metals increases with the distance away from highway, reaching a maximum value, and then decreases gradually. Potential ecological risks of the soil metals are at moderate level on Wanliu transect, while slight level on the other transect. Concentrations of most soil heavy metals and their potential ecological risks present skewness distribution with the distance form highway roadbed. The highest risk indexes (RI) for different metals on Wanliu transect are among 50 ~100 m from highway roadbed, farther than that on Xiaowangzhuang transect at 35 m. Most of the soil samples on northern side of the highway show higher metal concentrations and potential ecological risks than that on southern side. The total risk index was contributed by the heavy metal of Cd (averagely 61.39%), which is the main factor of potential ecological risks. The grade standards for different ecological risk levels must be modified according to types and amount of pollutants studied and their toxic-response factors.
Until now, there are different opinions upon basic principles of environmental science. Few scholars believe that there are no unique basic principles in environment science, but many scientists disagree with this opinion. Based on the foundations of previous work, four basic principles of environmental science are put forward in this paper: systematic principle of environment, principle of environmental capacity, symbiosis principle of human between environment, and entropy principle.
Sixteen tree-rings of Polar (P. Euramericana) were collected in the different function districts of Kaifeng City, China. Concentrations of Cu and Zn in the xylem of tree-rings from 1990 to 2009 were measured using F-AAS, and that of Co using ICP-MS. The results show that concentrations of Cu and Zn in tree-rings in the control area do not vary significantly in the period from 1990 to 2009 and much lower than that in urban areas. The accumulation sequences of Zn in tree-rings in different urban districts appear increasing trends in the period, and that of Cu present waved rising trends. The sequences of Co in tree-rings both in urban and control area had no significant change in the period. Copper and Zinc are the typical anthropogenic metals, and Co is a natural source metal. We can understand the heavy metal pollution changes in urban area from their accumulation sequences in tree-rings.
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