通过对黑龙江省四城市保护地四种土壤活性重金属含量变化趋势的研究表明 :新、老保护地表层土壤活性铅含量相差不大 ,中、下层则有增有减 ,也有整体剖面下降的情况。另外土壤活性铅含量在地域上初步表现出由西向东增加的趋势。土壤活性砷含量增减无规律性 ,在地域上有自东向西略有增加的趋势。随着时间推移各市保护地表层土壤活性镉含量均有增加 ,地域上变化不大。土壤活性汞在各市土样中均未检出。总之 ,各市保护地表层土壤活性重金属递增或递减规律性差。其原因是地域复杂 ,随施用、灌溉混入含重金属物质的各类肥料、农药、灌溉水等有关。 Through the study on the trend of active heavy metals contents in four kinds of soils in the four cities of Heilongjiang Province, the content of active lead in the surface soil of the new and old protected areas shows little difference but increases and decreases in the middle and lower layers, and the overall profile decreases. In addition, the soil active lead content initially showed a trend of increasing from west to east in the area. There was no regular increase or decrease in soil active arsenic content, which showed a slight increase from east to west in geography. With the passage of time, active cadmium levels in surface protective soils increased in all cities, with little change in the area. Soil active mercury was not detected in all municipal soil samples. In short, municipalities in the protection of surface soil active heavy metals increase or decrease the law of bad. The reason is that the geographical complex, with the application, irrigation, mixed with various types of heavy metals containing fertilizers, pesticides, irrigation water and so on.