黎清华, 万世明, 何军, 李安春. 近两百年来人类活动对北部湾潮间带环境的影响[J]. 海洋地质与第四纪地质, 2014, 34(1): 57-64. DOI: 10.3724/SP.J.1140.2014.01057
引用本文: 黎清华, 万世明, 何军, 李安春. 近两百年来人类活动对北部湾潮间带环境的影响[J]. 海洋地质与第四纪地质, 2014, 34(1): 57-64. DOI: 10.3724/SP.J.1140.2014.01057
LI Qinghua, WAN Shiming, HE Jun, LI Anchun. HUMAN IMPACT ON THE INTERTIDAL ENVIRONMENT IN BEIBU GULF OVER THE LAST 200 YEARS[J]. Marine Geology & Quaternary Geology, 2014, 34(1): 57-64. DOI: 10.3724/SP.J.1140.2014.01057
Citation: LI Qinghua, WAN Shiming, HE Jun, LI Anchun. HUMAN IMPACT ON THE INTERTIDAL ENVIRONMENT IN BEIBU GULF OVER THE LAST 200 YEARS[J]. Marine Geology & Quaternary Geology, 2014, 34(1): 57-64. DOI: 10.3724/SP.J.1140.2014.01057

近两百年来人类活动对北部湾潮间带环境的影响

HUMAN IMPACT ON THE INTERTIDAL ENVIRONMENT IN BEIBU GULF OVER THE LAST 200 YEARS

  • 摘要: 对北部湾潮间带两个柱状岩心沉积物进行了210Pb测年、粒度分布特征和重金属元素含量分析,并探讨了近两百年来人类活动对沉积环境的影响。结果表明,YX07和YX05岩心的平均沉积速率分别为0.45和0.37 cm/a,分别约记录了231年和210年以来的环境历史。重金属元素含量变化特征与沉积物平均粒径变化大体相反,说明重金属元素倾向于在细粒级物质中富集;不活泼微量元素比值La/Th的大小及其在岩心深度上的稳定变化,说明两个岩心物源的同一性且一直没有发生明显变化。岩心沉积物记录的沉积环境在1930年以前主要是自然影响,而1930年以来则更多受到人类活动影响,1930年以来岩心沉积物粒度变粗,可能因为人口的增加和土地的开垦等因素,在自然降水量降低的情况下人为地增加土壤物理侵蚀。同时,岩心中Al校正后重金属元素As、Pb、Cu等的含量从1930年直线增加2~3倍,则表明大量工业和生活污水经河流倾泻到河口和近岸地区,致使潮间带沉积物中重金属污染状况严重。

     

    Abstract: Multiple approaches including 210Pb dating, grain-size distribution and heavy metal elements (Hg, Cd, As, Pb, Cu, Cr, and Zn) concentration of sediments from two cores in the intertidal zone of Beibu Gulf were used for exploring the human impact on sedimentary environment for the last 200 years. The average sedimentation rate of cores YX07 and YX05 is 0.45 cm/a and 0.37 cm/a, respectively. The two cores span the last 231 and 210 years. The downcore concentration of heavy metal elements generally shows a contrary trend as mean grain-size, suggesting that heavy metal elements tend to be rich in finer grain-size materials. The similar values and stable downcore variation in ratio of trace elements (La/Th) in sediments of the both cores indicate that the sediment sources of the two cores are similar and not changed through time. The sedimentary environment before 1930 was influenced by nature factors, whereas largely influenced by human activity after the time. The mean grain-size became coarser since about 1930, possibly resulted from strengthened physical erosion of soils by stronger anthropogenic impact. Moreover, the 2~3 times increase in Al-normalized heavy minerals such as As, Pb, and Cu since the time suggests that vast industry and domestic wastewater was poured to the estuarine and coastal area, and thus deteriorated the environment of the intertidal zones.

     

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