Study On Soil Environmental Characteristics Of A Typical Non-resident Island

Due to its natural geographical isolation,Shanghai Dajinshan Island is less invaded by humans and is the largest local plant gene pool in Shanghai.However,pollutants such as heavy metals are transported through the atmosphere and are enriched in the soil,causing soil pollution.The pollution of heavy mental condition can reflect the whole pollution level of the soil.The problem of soil pollution is increasing seriously with human’s life,industrial manufacture,transport discharge and other resouces.Therefore,we conducted this survey of Dajinshan Island land area,collected 780specimen in different seasons to study the soil physical and chemical properties of Dajinshan Island.This analysis of soil heavy metal pollution in dajinshan island is expected to provide some reference value for further monitoring soil background and heavy metal pollution in non-resident islands in the future.The results show:（1）The soil texture of Dajinshan Island is clay loam;the soil bulk density is 0.81±0.16 g·cm^-3,the porosity is 49.0±7.4%,the field water holding rate is 40.7±7.5%;the soil aggregate is mainly from 0.05⁰.25.The composition of mm is agglomerate.（2）The soil ammonium nitrogen concentration is between 7.0±3.1¹0.4±3.0 mg·kg^-1,the non-nitrate nitrogen concentration is between 13.2±6.2 and 136.4±58.7 mg·kg^-1,and the total phosphorus content is between 0.87 and 2.39 g.·Between kg^-1,the effective phosphorus concentration is between 57.1±40.2 and 92.3±53.0mg·kg-1,the total potassium content is between 0.07 and 8.9 g·kg^-1,and the available potassium concentration is between 0.14±0.04⁰.26.Between±0.09 mg·kg^-1.（3）The over-standard rates of Hg,Cd,Cu,Pb,Zn,As,and Cr in Dajinshan Island were 96.4%,94.0%,76.2%,47.6%,33.3%,10.8%,and1.2%,respectively.The average concentrations of Pb,Cd and Cu increased in different degrees compared with 2011.Compared with the same period in2011,the change of soil Zn concentration in Dajinshan Island in 2017 was not obvious.The average concentrations of Pb,Cd,Cu,Zn and Hg in Dajinshan Island were significantly higher than those in other forests.The average Cr concentration was lower than that of other forest soils as control.The As concentration was very close to that of the control forest soil.（4）Hg and Cd are the most polluted,Pb and Cu are relatively polluted,and have similar spatial distribution patterns,which may come from the same source of pollution.Cr,As,and Zn are less polluted and may be less affected by humans.