居住区内植物叶面尘中重金属累积特征

Characteristics of heavy metals accumulation in plant leaf dust in residential area

选取城区居住区内大叶女贞等7种绿化树种叶片为研究材料,测定其单位叶面积滞尘量、叶面尘中和叶内重金属含量,并分析两者的相关性,研究不同绿化树种对大气粉尘中各重金属的吸附滞留能力。结果表明,单位叶面积滞尘量大小表现为海桐(2.50 g/m^(2))>金森女贞(2.26 g/m^(2))>桂花(2.01 g/m^(2))>大叶女贞(1.50 g/m^(2))>广玉兰(1.20 g/m^(2))>香樟(1.11 g/m^(2))>大叶黄杨(0.97 g/m^(2))。叶片中重金属含量高低排序为Mn(49.026 mg/kg)>Cr(5.308 mg/kg)>Cu(5.138 mg/kg)>Ni(2.436 mg/kg)>Pb(1.986 mg/kg)>As(0.359 mg/kg)>Cd(0.063 mg/kg)。叶面尘中Cr-Ni、Cr-Cu、Mn-Ni、Mn-Cu、Mn-Cd、Ni-Cu、As-Pb以及叶内Cr-Ni、Mn-Cu、Cu-Cd之间均存在明显相关性(P<0.01);叶面尘中Cr-Mn、Cr-As、Ni-As、Cu-Cd以及叶内Cr-Cd、Cu-As存在相关关系(P<0.05)。海桐对大气粉尘的滞尘能力和吸附大气重金属能力较强,可作为城市绿化优选树种。

The leaves of 7 different green tree species including Ligustrum compactum in urban residential areas were selected as research materials to determine the dust retention per unit leaf area and heavy metal content in leaf surface,and the correlation between the two were analyzed to screen the adsorption and retention capacity of different green tree species on heavy metals in atmospheric dust.The results showed that the dust retention per unit leaf area was as follows:Pittosporum tobira(2.50 g/m^(2))>Ligustrum japonicum(2.26 g/m^(2))>Osmanthus(2.01 g/m^(2))>Ligustrum compactum(1.50 g/m^(2))>Magnolia Grandiflora(1.20 g/m^(2))>Cinnamomum camphor(1.11 g/m^(2))>Buxus megistophylla(0.97 g/m^(2)).The order of heavy metal content in leaves were Mn(49.026 mg/kg)>Cr(5.308 mg/kg)>Cu(5.138 mg/kg)>Ni(2.436 mg/kg)>Pb(1.986 mg/kg)>As(0.359 mg/kg)>Cd(0.063 mg/kg).There were a significant correlation(P<0.01)between Cr-Ni,Cr-Cu,Mn-Ni,Mn-Cu,Mn-Cd,Ni-Cu,As-Pb and Cr-Ni,Mn-Cu,Cu-Cd in leaf dust.There were a significant positive correlation(P<0.05)between Cr-Mn,Cr-As,Ni-As,Cu-Cd in leaf dust and Cr-Cd,Cu-As in leaf dust.Pittosporum tobira had a strong dust retention ability and heavy metal adsorption ability to atmospheric dust,which could be used as the preferred tree species for urban greening.