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砷是地球上分布最广的剧毒类金属,具有生物累积性和不可降解性,可通过水、大气和食物等途径进入人体并对人体健康造成危害[1-4],目前已被国际癌症研究中心等列为一类致癌物. 砷的来源主要包括岩石的自然风化和人类生产和生活产生的含砷废弃物[5],环境砷污染问题随着人类社会的发展和工业化进程的加速而呈加剧趋势[6],特别是在人口密集、人类活动强烈的沿海地区. 含砷物质通过径流输送、直接排放、大气沉降等多种方式源源不断进入河口区域,其中的砷及砷化物可在水生生物体内积累,干扰其新陈代谢,甚至对生物群落结构产生影响,导致生态系统失衡[3,7],并可能经由食物链对人类健康产生潜在威胁. 进入水体中的砷等化学物质大部分会通过各种物理、化学和生物途径迅速由水相转入固相并最终进入沉积物中累积,使得河口和近岸区域沉积物成为污染物的主要存储库[8]. 另一方面,当水体环境发生变化时,沉积物结合的砷还可通过化学和生物循环再次回到水中,导致水体二次砷污染[9-10]. 因此,沉积物既是水体污染物的汇,又是水体污染物的源,其质量状况直接关系到水质的优劣.
珠江口位于粤港澳大湾区的核心部位,也是我国环境污染最严重的入海河口之一,其中也包括重金属污染. 砷虽不是金属,但因其毒性与重金属相近,因而在环境重金属污染研究中,也常把砷计入其中. 但通过查阅近40年来的调查数据发现,关于珠江口海域砷的监测数据相对其他重金属依然少得多,且由于不同时期的调查工作覆盖范围有差异,布设样点的位置、疏密程度、采用的测试分析方法等不同,使得关于珠江口表层沉积物砷含量的统计结果差异颇大[11-17],可比性差,不利于区域环境演化趋势分析.
伶仃洋是珠江口各种污染物含量最高的海区[11]. 本项工作即选取珠江口伶仃洋为研究区域,分析其表层沉积物和水体中砷含量的时空变化特征,以期为区域环境保护和综合治理提供基础依据.
珠江口伶仃洋水体及表层沉积物砷污染时空变化
Temporal and spatial change of Arsenic pollution in water and surface sediments of Lingding Bay, Pearl River Estuary
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摘要: 为了解珠江口伶仃洋砷污染状况,分别于2010年12月和2020年12月在该海域布点取样,样点布设位置和数量基本一致. 2010年仅采集了表层沉积物样品,2020年采集了表层沉积物和水体样品,分别使用原子荧光法和ICP-MS法测试了水体和沉积物砷含量. 结果显示,2020年时伶仃洋水体中溶解态的砷含量在2 μg·L−1左右,空间差异性小,与1976年以来的其他调查结果相近,指示该海域的水体砷含量在近40余年间未发生明显变化. 2020年时表层沉积物砷平均含量为52. 98 mg·kg−1,较2010年时(平均25.40 mg·kg−1)增加了1倍;空间分布上,由2010年时总体上从口门水道向外海方向递减的特征变为了2020年时的由近岸向远岸方向递增的特点. 综合分析认为,近10年间,除来自陆域的砷输入总量依然较大之外,持续加剧的海上人类活动可能向水中排放了更多的含砷污染物,加上人类活动的强烈扰动及水环境变化(如持续富营养化)导致的底泥中的砷释放和再沉淀作用等,共同导致了砷在沉积物表层的进一步富集和在空间上的重新分配. 总之,珠江口伶仃洋区域砷污染的潜在风险依然较为严峻,后期仍需加强监测和修复等相关工作.Abstract: In December 2010 and December 2020, samples were taken in the Lingding Bay of the Pearl River Estuary to investigate its arsenic pollution change. These samplings were of nearly the same locations and quantities. Only surface sediment samples were collected in 2010, while surface sediment and water samples were collected in 2020. The arsenic contents of the water samples and all sediment samples were measured by using atomic fluorescence spectrometry (AFS) and ICP-MS, respectively. The results showed that the dissolved arsenic content in the water of Lingding Bay was about 2 μg·L−1 with no significant deference in geographical distribution, which was similar to previous results since 1976, indicating that the arsenic content in the water of this sea area has not changed significantly during the past 40 years. The mean arsenic content of surface sediment was 52.98 mg·kg−1 in 2020, which is twice as that in 2010 (25.40 mg·kg−1 on average). In 2010, the arsenic content of surface sediment decreased gradually from the watercourses to the open sea, while the spatial distribution characteristics of sediments arsenic content in 2020 was almost opposite to that in 2010. After a comprehensive analysis, it was believed that the main reasons for these changes in arsenic content of surface sediment during the past 10 years were as follows: 1) The total amount of arsenic input from land areas was still large, 2) increased human activities on the water input more arsenic containing pollutants into the water, 3) The intense disturbance of human activities and changes of water environment had led to the release and transfer of arsenic in the sediment to the surface. In general, the potential risk of arsenic pollution in the Lingding Bay of the Pearl River Estuary was still severe. Further monitoring and remediation work should be enhanced in the later stage.
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Key words:
- Lingding Bay /
- water /
- surface sediment /
- arsenic pollution /
- spatio-temporal change.
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表 1 伶仃洋表层沉积物中砷富集系数统计表
Table 1. Statistics of enrichment factor of arsenic in surface sediments of Lingding Bay
富集系数
Enrichment factor富集(人为影响)程度
Enrichment (human impact) degree占比/%
Percentage2020年 2010年 ≤1 无 0.00 3.57 1—2 轻微 0.00 25.00 2—5 中度 34.62 71.43 5—20 显著 65.38 0.00 表 2 沉积物砷含量统计表(mg·kg−1)
Table 2. The statistical characteristics of arsenic in the Pearl River Estuary and Delta(mg·kg−1)
样本类型
Sample type采样时间
Sampling time含量范围
Range平均值
Average样本数
Number of samples文献
Reference分析方法
Method伶仃洋表层沉积物 2010 7.00—47.30 25.40 28 本研究 ICP-MS 2020 19.20—89.90 52.98 26 本研究 ICP-MS 珠江三角洲第四纪沉积物 — 1.00—45.71 8.17 171 [20] ICP-OES 西江沉积物(河池以下) 2015 11.12—107.18 34.23 68 [38] ICP-MS 西江沉积物(梧州以下) 2015 12.88—68.10 29.74 22 [39] ICP-OES 北江沉积物(韶关以下) 2015 1.44—95.80 28.39 16 [39] ICP-OES 东江沉积物(惠州以下) 2015 3.44—22.54 9.59 10 [39] ICP-OES 表 3 伶仃洋表层沉积物砷污染潜在生态危害系数
统计表$ {E}_{r}^{i} $ Table 3. Potential ecological risk factor of arsenic pollution in surface sediments of Lingding Bay
$ {E}_{\mathrm{r}}^{i} $ 风险程度
Risk degree占比/%
Percentage2020年 2010年 < 40$ {E}_{\mathrm{r}}^{i} $ 轻微 15.38 82.14 40≤ <80$ {E}_{\mathrm{r}}^{i} $ 中等 53.85 17.86 80≤ <160$ {E}_{\mathrm{r}}^{i} $ 强 30.77 0.00 160≤ <320$ {E}_{\mathrm{r}}^{i} $ 很强 0.00 0.00 ≥320$ {E}_{\mathrm{r}}^{i} $ 极强 0.00 0.00 -
[1] 董飞, 卢瑛, 张建国, 等. 珠江三角洲稻田土壤砷及其向水稻籽粒迁移特征 [J]. 生态环境学报, 2009, 18(6): 2137-2140. doi: 10.3969/j.issn.1674-5906.2009.06.025 DONG F, LU Y, ZHANG J G, et al. Soil arsenic concentration in paddy fields and its transfer to rice (Oryza sativa L. ) grain in Pearl River Delta [J]. Ecology and Environmental Sciences, 2009, 18(6): 2137-2140(in Chinese). doi: 10.3969/j.issn.1674-5906.2009.06.025
[2] 陈保卫, LE X C. 中国关于砷的研究进展 [J]. 环境化学, 2011, 30(11): 1936-1943. CHEN B W, LE X C. Recent progress in arsenic research in China [J]. Environmental Chemistry, 2011, 30(11): 1936-1943(in Chinese).
[3] FLORA S J S (Edited). Handbook of Arsenic Toxicology[M]. Academic Press, Oxford: Academic Press, 2015. [4] WANG J W, WAN Y J, CHENG L, et al. Arsenic in outdoor air particulate matter in China: Tiered study and implications for human exposure potential [J]. Atmospheric Pollution Research, 2020, 11(4): 785-792. doi: 10.1016/j.apr.2020.01.006 [5] MATSCHULLAT J. Arsenic in the geosphere-a review [J]. Science of the Total Environment, 2000, 249(1/2/3): 297-312. [6] 王奎克, 朱晟, 郑同, 等. 砷的历史在中国 [J]. 自然科学史研究, 1982, 1(2): 115-126. WANG K K, ZHU S, ZHENG T, et al. The history of arsenic in China [J]. Studies in the History of Natural Sciences, 1982, 1(2): 115-126(in Chinese).
[7] 胡文渊, 赵帅营, 张涛, 等. 砷污染下阳宗海浮游动物群落特征及其影响因素 [J]. 生态学杂志, 2021, 40(10): 3195-3204. HU W Y, ZHAO S Y, ZHANG T, et al. Characteristics and driving factors of zooplankton community in arsenic-polluted Yangzong Lake [J]. Chinese Journal of Ecology, 2021, 40(10): 3195-3204(in Chinese).
[8] 蓝先洪. 珠江口表层沉积物的地球化学特征 [J]. 海洋湖沼通报, 1989(4): 53-61. LAN X H. Geochemical characteristics of surface sediment in the Pearl River Estuary [J]. Transactions of Oceanology and Limnology, 1989(4): 53-61(in Chinese).
[9] SMEDLEY P L, KINNIBURGH D G. A review of the source, behaviour and distribution of arsenic in natural waters [J]. Applied Geochemistry, 2002, 17(5): 517-568. doi: 10.1016/S0883-2927(02)00018-5 [10] GORNY J, BILLON G, LESVEN L, et al. Arsenic behavior in river sediments under redox gradient: A review [J]. Science of the Total Environment, 2015, 505: 423-434. doi: 10.1016/j.scitotenv.2014.10.011 [11] 温伟英, 何悦强. 珠江口海岸带底质污染现状分析[C]//珠江口海岸带和海涂资源综合调查研究文集(二). 广州: 广东科技出版社, 1985. WEN W Y, HE Y Q. Analysis on the current situation of sediment pollution in the coastal zone of the Pearl River Estuary[C]//Collected papers on the comprehensive investigation of the coastal zone and sea beach resources in the Pearl River Estuary (Ⅱ). Guangzhou: Guangdong Science and Technology Press, 1985(in Chinese).
[12] 刘芳文, 颜文, 黄小平, 等. 珠江口沉积物中重金属及其相态分布特征 [J]. 热带海洋学报, 2003, 22(5): 16-24. LIU F W, YAN W, HUANG X P, et al. Distributional characteristics of heavy metal and its available phases in sediments from Zhujiang River mouth [J]. Journal of Tropical Oceanography, 2003, 22(5): 16-24(in Chinese).
[13] 石要红, 梁开, 夏真. 珠江口伶仃洋海底表层沉积物重金属污染及潜在生态危害评价 [J]. 南海地质研究, 2006(1): 52-59. SHI Y H, LIANG K, XIA Z. Pollution of heavy metals in the Lingdingyang of Pearl River Estuary and its assessment of potential ecological risk [J]. Geological Research of South China Sea, 2006(1): 52-59(in Chinese).
[14] 甘华阳, 梁开, 郑志昌. 珠江口表层沉积物中微量元素地球化学 [J]. 海洋地质与第四纪地质, 2010, 30(4): 131-139. GAN H Y, LIANG K, ZHENG Z C. Trace elements geochemical characteristics of the surface sediments of pear river estuary [J]. Marine Geology & Quaternary Geology, 2010, 30(4): 131-139(in Chinese).
[15] 倪志鑫, 张霞, 蔡伟叙, 等. 珠江口沉积物中重金属分布、形态特征及风险分析 [J]. 海洋环境科学, 2016, 35(3): 321-328. NI Z X, ZHANG X, CAI W X, et al. Distribution, speciation and risk assessment of trace metals in surface sediment of the Zhujiang Estuary [J]. Marine Environmental Science, 2016, 35(3): 321-328(in Chinese).
[16] BI S P, YANG Y, XU C F, et al. Distribution of heavy metals and environmental assessment of surface sediment of typical estuaries in Eastern China [J]. Marine Pollution Bulletin, 2017, 121(1/2): 357-366. [17] 吴鹏, 刘永, 李纯厚, 等. 珠江口沉积物中重金属和石油污染对微生物群落结构的影响 [J]. 海洋湖沼通报, 2022, 44(1): 106-114. WU P, LIU Y, LI C H, et al. Effects of heavy metals and oil in sediments of Pearl River Estuary on microbial community [J]. Transactions of Oceanology and Limnology, 2022, 44(1): 106-114(in Chinese).
[18] 黄镇国, 李平日, 张仲英. 珠江三角洲形成发育演变[M]. 广州: 科学普及出版社广州分社, 1982. HUANG Z G, LI P R, ZHANG Z Y, et al. Formation, development and evolution of Pearl River Delta[M]. Guangzhou: Guangzhou Branch of Science Popularization Press, 1982(in Chinese).
[19] XIONG H X, ZONG Y Q, HUANG G Q, et al. Human drivers accelerated the advance of Pearl River Deltaic shoreline in the past 7500 years [J]. Quaternary Science Reviews, 2020, 246: 106545. doi: 10.1016/j.quascirev.2020.106545 [20] 唐志敏, 侯青叶, 游远航, 等. 珠三角平原区第四系剖面重金属分布特征及其影响因素 [J]. 地球科学进展, 2017, 32(8): 885-898. TANG Z M, HOU Q Y, YOU Y H, et al. Distribution characteristics and influencing factors of heavy metals in Pearl River Delta quaternary boreholes [J]. Advances in Earth Science, 2017, 32(8): 885-898(in Chinese).
[21] ZOLLER W H, GLADNEY E S, DUCE R A. Atmospheric concentrations and sources of trace metals at the South pole [J]. Science, 1974, 183(4121): 198-200. doi: 10.1126/science.183.4121.198 [22] 李文胜, 窦磊, 刘子宁. 珠江三角洲平原区第四纪沉积物地球化学特征及其控制因素 [J]. 华南地质与矿产, 2016, 32(1): 68-77. LI W S, DOU L, LIU Z N. Element geochemical characteristics and controlling factors of the Quaternary Sediments in the Pearl River Delta plain [J]. Geology and Mineral Resources of South China, 2016, 32(1): 68-77(in Chinese).
[23] HAKANSON L. An ecological risk index for aquatic pollution control. a sedimentological approach [J]. Water Research, 1980, 14(8): 975-1001. doi: 10.1016/0043-1354(80)90143-8 [24] 徐争启, 倪师军, 庹先国, 等. 潜在生态危害指数法评价中重金属毒性系数计算 [J]. 环境科学与技术, 2008, 31(2): 112-115. XU Z Q, NI S J, TUO X G, et al. Calculation of heavy metals' toxicity coefficient in the evaluation of potential ecological risk index [J]. Environmental Science & Technology, 2008, 31(2): 112-115(in Chinese).
[25] 贾钧博, 张嘉成, 张浩楠, 等. 珠江口水体中重金属含量及其生态风险评价 [J]. 东莞理工学院学报, 2021, 28(1): 54-60. JIA J B, ZHANG J C, ZHANG H N, et al. Content and ecological risk assessment of heavy metal in Pearl River Estuary [J]. Journal of Dongguan University of Technology, 2021, 28(1): 54-60(in Chinese).
[26] 杜韶娴. 珠江出海口门水环境中砷、汞、铅、镉的测定及评价[D]. 广州: 华南理工大学, 2012. DU S X. Determination and evaluation of arsenic, mercury, lead and cadmium in the water environment of the Pearl River Estuary[D]. Guangzhou: South China University of Technology, 2012 (in Chinese).
[27] 张亚南, 贺青, 陈金民, 等. 珠江口及其邻近海域重金属的河口过程和沉积物污染风险评价 [J]. 海洋学报, 2013, 35(2): 178-186. ZHANG Y N, HE Q, CHEN J M, et al. Heavy metals' process in water and pollution risk assessment in surface sediments of the Zhujiang River Estuary [J]. Acta Oceanologica Sinica, 2013, 35(2): 178-186(in Chinese).
[28] 张银英, 郑庆华, 何悦强, 等. 珠江口咸淡水交汇区水中CODMn、油类、砷自净规律的试验研究 [J]. 热带海洋, 1995, 14(3): 67-74. ZHANG Y Y, ZHENG Q H, HE Y Q, et al. An experimental study on the self-purification of CODMn, oil and As in the mixing area of saltwater and freshwater in Zhujiang River Estuary [J]. Tropic Oceanology, 1995, 14(3): 67-74(in Chinese).
[29] 柯东胜. 珠江口海水中砷的含量和分布 [J]. 海洋环境科学, 1985, 4(2): 24-27. KE D S. Content and distribution of arsenic in seawater of the Pearl River Estuary [J]. Marine Environmental Science, 1985, 4(2): 24-27(in Chinese).
[30] KALIA K, KHAMBHOLJA D B. Arsenic contents and its biotransformation in the marine environment//Hand-book of arsenic toxicology[M]. Oxford: Academic Press, 2015: 675-700. [31] 柳青青, 杨忠芳, 周国华, 等. 中国东部主要入海河流As元素分布、来源及影响因素分析 [J]. 现代地质, 2012, 26(1): 114-124. LIU Q Q, YANG Z F, ZHOU G H, et al. Distribution, sources and impact factors of arsenic in the major rivers of Eastern China [J]. Geoscience, 2012, 26(1): 114-124(in Chinese).
[32] TAYLOR S R, McLENNAN S M. The geochemical evolution of the continental crust [J]. Reviews of Geophysics, 1995, 33(2): 241-265. doi: 10.1029/95RG00262 [33] HANS WEDEPOHL K. The composition of the continental crust [J]. Geochimica et Cosmochimica Acta, 1995, 59(7): 1217-1232. doi: 10.1016/0016-7037(95)00038-2 [34] WU W H, QU S Y, NEL W, et al. Tracing and quantifying the sources of heavy metals in the upper and middle reaches of the Pearl River Basin: New insights from Sr-Nd-Pb multi-isotopic systems [J]. Chemosphere, 2022, 288: 132630. doi: 10.1016/j.chemosphere.2021.132630 [35] 张秀芝, 鲍征宇, 唐俊红. 富集因子在环境地球化学重金属污染评价中的应用 [J]. 地质科技情报, 2006, 25(1): 65-72. ZHANG X Z, BAO Z Y, TANG J H. Application of the enrichment factor in evaluating of heavy metals contamination in the environmental geochemistry [J]. Geological Science and Technology Information, 2006, 25(1): 65-72(in Chinese).
[36] SUTHERLAND R A. Bed sediment-associated trace metals in an urban stream, Oahu, Hawaii [J]. Environmental Geology, 2000, 39(6): 611-627. doi: 10.1007/s002540050473 [37] BLASER P, ZIMMERMANN S, LUSTER J, et al. Critical examination of trace element enrichments and depletions in soils: As, Cr, Cu, Ni, Pb, and Zn in Swiss forest soils [J]. Science of the Total Environment, 2000, 249(1/2/3): 257-280. [38] 汝旋. 人类活动对河流表层沉积物中重金属分布区域差异性的影响评估: 以西江为例[D]. 广州: 华南理工大学, 2018. RU X. Impact assessment of human activities on regional difference of heavy metals distribution in river surface sediments-Taking Xijiang River as an example[D]. Guangzhou: South China University of Technology, 2018 (in Chinese).
[39] 唐志敏. 珠江水系对冲积平原区土壤环境质量的影响[D]. 北京: 中国地质大学(北京), 2017. TANG Z M. Influence of Pearl River system on soil environmental quality in alluvial plain area[D]. Beijing: China University of Geosciences, 2017 (in Chinese).
[40] 赵艺, 刘子宁, 陈恩. 珠江水系沉积物重金属元素含量特征及评价 [J]. 地球, 2013, 7: 273-273,120. ZHAO Y, LIU Z N, CHEN E. Content characteristics and evaluation of heavy metals in sediments of Pearl River system [J]. The Earth, 2013, 7: 273-273,120(in Chinese).
[41] LI C, SANCHEZ G M, WU Z F, et al. Spatiotemporal patterns and drivers of soil contamination with heavy metals during an intensive urbanization period (1989–2018) in Southern China [J]. Environmental Pollution, 2020, 260: 114075. doi: 10.1016/j.envpol.2020.114075 [42] 安礼航, 刘敏超, 张建强, 等. 土壤中砷的来源及迁移释放影响因素研究进展 [J]. 土壤, 2020, 52(2): 234-246. AN L H, LIU M C, ZHANG J Q, et al. Sources of arsenic in soil and affecting factors of migration and release: A review [J]. Soils, 2020, 52(2): 234-246(in Chinese).
[43] 黄光庆, 杨龙, 蒋冲, 等. 粤港澳大湾区城市群生态系统变化研究[M]. 广州: 广东省科技出版社, 2022. HUANG G Q, YANG L, JIANG C, et al. Study on the ecosystem change of urban agglomeration in the Greater Bay Area of Guangdong, Hong Kong and Macao [M]. Guangzhou: Guangdong Science and Technology Press, 2022(in Chinese).
[44] 吴万富, 徐艳, 史德强, 等. 我国河流湖泊砷污染现状及除砷技术研究进展[J]. 环境科学与技术, 2015, 38(增刊1): 190-197. WU W F, XU Y, SHI D Q, et al. The arsenic pollution status of the rivers and lakes in China and the research progress on arsenic removal techniques[J]. Environmental Science & Technology, 2015, 38(Sup 1): 190-197 (in Chinese).
[45] DANG D H, TESSIER E, LENOBLE V, et al. Key parameters controlling arsenic dynamics in coastal sediments: An analytical and modeling approach [J]. Marine Chemistry, 2014, 161: 34-46. doi: 10.1016/j.marchem.2014.02.005 [46] LI L, REN J L, CAO X H, et al. Process study of biogeochemical cycling of dissolved inorganic arsenic during spring phytoplankton bloom, southern Yellow Sea [J]. Science of the Total Environment, 2017, 593/594: 430-438. doi: 10.1016/j.scitotenv.2017.03.113