Heavy metal accumulation characteristics and physiological response of Sabina chinensis and Platycladus orientalis to atmospheric pollution

Heavy metal(Cu,Mn,Zn,Pb,and Cd)concentrations were measured in the leaves of Sabina chinensis and Platycladus orientalis collected from urban,suburban,and rural sites in Tianjin,China.Photosynthetic pigment contents,reactive oxygen species content,malondialdehyde(MDA)content and antioxidant enzyme activity were investigated,providing physiological response parameters.Our comparison of the sites revealed that urbanization significantly influenced the heavy metal concentrations in both plant leaves.At the rural site,both plant leaves exhibited the lowest heavy metal accumulation.The highest Cu,Mn,and Zn concentrations were found in S.chinensis leaves from the urban site;the highest Pb and Cd concentrations were found in P.orientalis leaves from the urban site.These results indicate that the urban site contained larger heavy metal concentrations in the plant leaves that may reflect the anthropogenic emission gradient.It is also found that S.chinensis may be used to monitor airborne heavy metal pollution because it is highly quick response to heavy metals,while P.orientalis may be used for mitigation due to its high resistance.The results of this study can contribute to the development of monitoring and environmental management plans by providing information on sensitive and resistant tree species for city greening in North China.

Factors influencing the contents of metals and As in soils around the watershed of Guanting Reservoir,China

Topsoil samples from 61 sites around the Guanting Reservoir,China,were measured for Cu,Zn,Cr,Ni,Cd,Pb and As concentrations.The mean concentrations of Cu,Zn,Cr,Ni,Cd,Pb and As were 16.8,59.4,37.8,18.3,0.32,20.1 and 8.67 mg/kg dry weight,respectively.Factors that influence the dynamics of these metals in soils around the watersheds of Beijing reservoirs were examined.The influence of atmospheric deposition,land use,soil texture,soil type and soil chemical parameters on metal contents in soils was investigated.Atmospheric deposition,land use and soil texture were the important factors affecting heavy metal residues.Soil type and soil chemical parameters were also involved in heavy metal retention in soils.The data provided in this study are considered crucial for reservoir remediation,especially since the Guanting Reservoir will serve as one of the main drinking water sources for Beijing in the foreseeable future.