Effects Of China-russia Oil Pipeline Project On Speciation Of Heavy Metal In Soil Of Different Forest Types Passed By The Project

Using BCR sequential extraction method, we measured quality density of different chemical speciation of heavy metal in soils of different forest types along the Mohe-Daqing pipeline,and studied the effects of this pipeline project on contents of soil heavy metal Mn、Cu and Zn in Daxing, anling iegioii. The Ksults revealed that:(1)After laying the oil pipeline,the contents of total Mn in work zone all increased significantly(P<0.01)in spite of different fbrest types.The average content of total Mn in soil。of 0-20 cm layer was the highest and Kse by 2.31 times of ones in no work zone in Betula secondary forest,while the least increasement happened in Larix gemelinii forest with 0.53 times.The pipeline project also impond big influence on the speciation of Mn.In surface layer soil(0-20 cm)of work zone,the content of weak acid extractable Mn incieased by 1.19 times of background value for secondary forest,and was the higheamong tiiree type fbrests.whilee least incrcasemet occured in foiest with 0.47 times.Asr reducnle Mn,fbrest got the higheist tent whichis 7 times of relevant background value,and the Larix gemelinii forest possessed the least increasement with 1.40times.With respectthe tent of oxidizable Mn,the highest one occurred ineplatyphylla secondary forest which increased by 5.11 times of ones in no work zone,and they increased 3.20 times and 0.42 times in Pinus sylvestnis and Larix gemelinii forest,respectively.The average content sequece of iesidual Mn is(1.97 limes),ysylvestnis(0.42 times),Larix gemelinii(0.17 times).Due to this project,the proportion of residual Mn in total IV all decreased and for a secodary forest,Lar their loss were 4.63%,10,99%and 23.48%respectivelyhowever,the proportion of reducible Mn increased by9.02%,12.38%and 23.61 turns.Besides,the proportio of oxidizable Mn content of Betula platyphylla secondaryrest and rose by 5.46%and 2.27%,respectively.(2)The contents of total Cu in work zone alsoincreased(P<0.05)for all three typeforests in Daxing,anling.The average content of total Cu was the highest and increased by51.44%of one in no work zone in secondary forest,wherease least increasement appeared on daiy forest with 25.58%.The pipeline project also greatly ifluenced on the speciation of Cii. The tent of weak acid extractable Cu was the highest in larix gemelinii forests and compared no work zone,increased by 1.45 times.,And the least increasement happened in Pinus sylvestnis with 0.82times.times. The content of reducible Cu was the highest in Pinus sylvestnis with the increasement of 80.68% of ones in no work zone while the least increasement of 23.59% happened in Larix gemelinii forests. The content of oxidizable Cu was the highest in Pinus sylvestnis and compared to that of no work zone, it increase by 1.15 times, while the least increasement happened in Larix gemelinii and Betula platyphylla secondary forest with 0.50 times and 0.35 times, respectively. The average content sequence of residual Cu average content is Larix gemelinii (34.07%)> Pinus sylvestnis (18.35%)>Betula platyphylla (9.29%).The soil proportion of residual Cu in total Cu of Betula platyphylla forest, Larix gemelinii and Pinus sylvestnis work zone decreased by 12.91%,5.43% and 21.65% respectively; the reducible Cu content of Betula platyphylla secondary forest and Pinus sylvestnis rose by 25.56% and 19.63% respectively, While that of oxidizable Cu increased by 7.83% and 42.13%.(3) The contents of total Zn in work zone all increased significantly(P<0.05) in spite of different forest types in Daxing’anling, The average content of total Zn in soil of 0-20 cm layer was the highest and rose by 3.37 times of ones in no work zone in Betula platyphylla secondary forest, while the least increasement happened in Pinus sylvestnis with 0.44 times.The pipeline project also had a big influence on the speciation of Zn.The content of weak acid extractable Zn in soil of 0-20 cm layer was the highest and rose by 63.38% of ones in no work zone in Larix gemelinii,while the least increasement happened in Betula platyphylla forest with 17.57%; The content of reducible Zn was the highest and rose by 1.19 times of ones in no work zone in Pinus sylvestnis, while the least increasement happened in Betula platyphylla forest with 0.28 times; The content of oxidizable Zn was the highest and rose by 1.36 times of ones in no work zone in Larix gemelinii, while the least increasement happened in Mongolian pine forests and Betula platyphylla forest with 0.24 times and 0.18 times; The average content sequence of residual Zn is Betula platyphylla forest (4.36 times)> Larix gemelinii (1.43 times)> Pinus sylvestnis (0.39 times).The soil proportion of residual Mn in total Zn of Betula platyphylla secondary forest, Larix gemelinii and Pinus sylvestnis work zone decreased by 26.82%,7.97%. and 3.59% respectively, while that of reducible Mn of the Pinus sylvestnis increased by 0.96 separately; the oxidizable Zn content of Pinus sylvestnis rose by 3.01% respectively.