钢铁工业区降尘对周边土壤的影响

EFFECTS OF ATMOSPHERIC DUST ON SOILS IN INDUSTRIAL ZONES

分别在南京的两个钢铁厂收集降尘并采集周边表土,并用ICP-AES和磁化率仪分析得到16种元素含量和表土、地面尘的磁化率。结果表明,两个钢铁工业区的大气降尘的年沉降通量分别为190t km-2a-1和407 t km-2a-1,这可能会影响着周边地区土壤的形成;Al、K、Na、Ti、V在降尘中的含量显著低于表土,而Ca,Fe,Zn,Mn,Pb,Cu在降尘中含量要显著高于表土;表土的磁化率除水田外均大于100×10-8m3kg-1,并且地面尘的磁化率要远远高于表土的磁化率。研究表明,钢铁工业区降尘对其周边土壤中污染元素的积累有明显影响,突出地表现在土壤表层重金属含量升高,而磁化率可以很好地表征这种表聚的特点。

Samples of airborne dust and soils around the two steel factories in Nanjing were collected and their element concentrations were analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometry （ICP-AES） and their magnetic susceptibility determined by magnetic susceptibility analyzer. Results indicate that the deposition flux around the two steel factories was 190 t km^-2 a^-land 407 t km^-2 a^-l, respectively and the annual accumulation in soil surface due to dust deposition could reach up to 0.3 mm,which is an important contribution to soil formation in a long run. The contents of A1,K,Na,Ti,and V in the dust were lower than that in the surface soils, but Ca, Fe, Zn, Mn, Pb and Cu were much higher. The magnetic susceptibility （MS） of the surface soils was over 100 × 10^-8 m^3 kg^-l except that in the paddy field, and the MS of the roof dust was much higher than that of the surface soils. MS decreased sharply with depth in the several centimeters of soils around the factories, indicating an ob- vious surface enrichment of magnetic materials and heavy metals. The study reveals that the dust from industrial sources has a strong impact on the soils around, by causing enrichment of heavy metals in the soil surface and sharp rise in magnetic susceptibility.