Relationship between Heavy Metal Concentrations in Soils and Grasses of Roadside Farmland in Nepal

International Journal of Environmental Research and Public Health

Xuedong Yan³  Fan Zhang¹  Chen Zeng¹  Man Zhang³  Lochan Prasad Devkota² 

[1] Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China;Central Department of Hydorlogy and Meteorology, Tribhuvan University, Kathmandu 44618, Nepal;State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing 100044, China;

关键词: heavy metals (Cu;    Zn;    Cd;    and Pb);    roadside soil;    roadside grass;    farmland environment;    Nepal;   

DOI  :  10.3390/ijerph9093209

来源: mdpi

【 摘 要 】

Transportation activities can contribute to accumulation of heavy metals in roadside soil and grass, which could potentially compromise public health and the environment if the roadways cross farmland areas. Particularly, heavy metals may enter the food chain as a result of their uptake by roadside edible grasses. This research was conducted to investigate heavy metal (Cu, Zn, Cd, and Pb) concentrations in roadside farmland soils and corresponding grasses around Kathmandu, Nepal. Four factors were considered for the experimental design, including sample type, sampling location, roadside distance, and tree protection. A total of 60 grass samples and 60 topsoil samples were collected under dry weather conditions. The Multivariate Analysis of Variance (MANOVA) results indicate that the concentrations of Cu, Zn, and Pb in the soil samples are significantly higher than those in the grass samples; the concentrations of Cu and Pb in the suburban roadside farmland are higher than those in the rural mountainous roadside farmland; and the concentrations of Cu and Zn at the sampling locations with roadside trees are significantly lower than those without tree protection. The analysis of transfer factor, which is calculated as the ratio of heavy-metal concentrations in grass to those in the corresponding soil, indicates that the uptake capabilities of heavy metals from soil to grass is in the order of Zn > Cu > Pb. Additionally, it is found that as the soils’ heavy-metal concentrations increase, the capability of heavy-metal transfer to the grass decreases, and this relationship can be characterized by an exponential regression model.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.