HUMAN IMPACT ON THE INTERTIDAL ENVIRONMENT IN BEIBU GULF OVER THE LAST 200 YEARS
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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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Key words:
- Intertidal zone /
- sediments /
- heavy minerals /
- grain-size /
- environmental change
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[1] 廉雪琼.广西近岸海域沉积物中重金属污染评价[J].海洋环境科学,2002,21(3):39-42.
[LIAN Xuefeng. Heavy metals in sediment pollution assessment[J]. Marine Environmental Science, 2002, 21(3):39-42.]
[2] 张少峰,林明裕,魏春雷, 等.广西钦州湾沉积物重金属污染现状及潜在生态风险评价[J].海洋通报,2010,29(4):450-454.
[ZHANG Shaofeng, LIN Mingyu, WEI Chunlei,et al. Pollution of heavy metals in sediments of Qinzhou Bay and potential ecological risk assessment[J]. Marine Science Bulletin, 2010,29(4):450-454.]
[3] 黎清华,万世明,李安春, 等.广西钦州湾-防城港潮间带表层沉积物重金属生态风险评价[J]. 海洋科学进展,2012,30(1):141-154.
[LI Qinghua, WAN Shiming, LI Anchun. et al. Qinzhou Bay-between Fangchenggang intertidal ecological risk assessment of heavy metals in surface sediments[J]. Advances in Marine Science, 2012, 30(1):141-154.]
[4] 夏鹏, 孟宪伟, 印萍, 等. 广西龙门岛潮间带近150年来环境演变的沉积记录[J]. 海洋地质与第四纪地质, 2011,31(1),51-59.
[XIA Peng, MENG Xianwei, YIN Ping, et al. Longmen Island intertidal sediment records of nearly 150 years of environmental evolution[J]. Marine Geology and Quaternary Geology, 2011, 31(1):51-59.]
[5] 李树华. 中国海湾志广西海湾分册[M]. 北京:海洋出版社, 1993, 144-148.[LI Shuhua. Gulf China Guangxi branch[M] Beijing:China Ocean Press, 1993, 144
-148.]
[6] Wentworth C K. A scale of grade and class terms of clastic sediments[J]. J. Geol., 1922, 30:377-392.
[7] Shepard F. Nomenclature based on sand-silt-clay ratios[J]. J Sediment. Petrol,1954, 24:151-158.
[8] 万国江,现代沉积的210Pb计年. 第四纪研究,1997,3,230-239.[WAN Guojiang. Modern deposited 210
Pb count[J]. Quaternary Research, 1997, 3:230-239.]
[9] 林祖亨,李国祺. 广东海岛环境质量调查报告[R].广州:广东科技出版社1995:115.[LIN Zuheng, LI Guoqi. Environmental Quality Survey Report of Guangdong islands[R]. Guangzhou:Guangdong Science and Technology Press, 1995:115.]
[10] 甘居利,贾晓平,李纯厚, 等. 南海北部陆架区表层沉积物中重金属分布和污染状况[J].热带海洋学报,2003,22(1):36-42.
[GAN Juli, JIA Xiaoping, LI Chunhou,et al. Surface sediments of the northern South China Sea continental shelf and distribution of heavy metals in polluted conditions[J]. Journal of Tropical Oceanography, 2003,22(1):36-42.]
[11] Balachandran K K, Raj C M L, Nair M, et al. Heavy metal accumulation in a flow restricted, tropical estuary:Estuarine Coastal and Shelf Science, 2005, 65(1-2):361-370, DOI 10.1016/j.ecss.2005.06.013/
[12] Mann M E, Jones P D. Global surface temperatures over the past two millennia[J]. Geophys Res Lett, 2003, 30:1820, doi:10.1029/2003GL017814
[13] Church J A, White N J. Sea-level rise from the late 19th to the early 21st Century[J]. Surveys in Geophysics, doi:10.1007/s10712-011-9119-1.
[14] Wang Y, Cheng H, Edwards R L, et al. The Holocene Asian Monsoon:Links to solar changes and North Atlantic climate[J]. Science, 2005, 308:854-857
[15] Xue Z, Liu J P, Ge Q A. Changes in hydrology and sediment delivery of the Mekong River in the last 50 years:connection to damming, monsoon, and ENSO[J]. Earth Surface Processes and Landforms, 2011, 36(3):296-308, Doi 10.1002/Esp.2036/
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