Distribution and accumulation of heavy metals in A vicennia marina communi ty in Shenzhen，China

This paper deals with the absorption，accumulation and distribution of several heavy metals in Avicennia marina community at Futian Nature Reserve in Shenzhen。China．The results showed that：(1)the contents of Cu，Ph，Zn，Cd，Cr，Ni and Mn in the topsoil(O---30cm in depth)were 38．3，28．7，11．4，0．136，7 97，25．0 and 537 μg/g respectively；(2)there were significant differences in the contents of heavy metals in different fractions of Avicennia marina，and the content ranges were 1．8—13．8 for Cu，0．4—3．51 for Pb；3．4—69．5 for Zn，0．013—0．295 for Cd，0．28—0．73 for Cr，0．43—7．65 for Ni and 25一1552 μg/g for Mn；(3)The enrichment coefficient (weighted mean) of the plants to topsoil was Cd>Mn>Zn>Cu>Ni=Cr>Pb；(4)the accumulation amounts of seven elements in standing biomass of this community were 53．70，19．27，187．89，0．72，6．06，20．76 and 1631．17 mg/m² for Cu，Pb，Zn，Cd，Cr，Ni and Mn respectively．The net retention amount in the community(1993)were 4．06，1．32，16．36，1．43，107．98 rag/(m²．a)for Cu，Pb，Zn，Ni and Mn，60．21 and 431．8Oμg／(m²．a)for Cd and Cr respectively；(5)the potential amounts of the elements which existed in the residues of soil surface in the community were 2．09，1．96，5．05，1．54 and 405．54 mg／m²for Cu，Pb，Zn，Ni and Mn，and which of Cd and Cr were 19．30 and 78．00 μg/m²，respectively．