-
我国产业结构的优化升级和城市化进程的加速,促使传统工业企业转型,纷纷由城市中心搬迁至工业园区[1]. 然而原有企业在运营期间,环保意识淡薄、管理不当,使原址场地中的土壤和地下水受到不同程度的污染,不仅给周边环境和居民健康带来威胁和风险,也使遗留场地的再次开发利用受到限制. 企业生产工艺的多元化与生产活动的长期性,导致了大多遗留场地属于污染物种类复杂、风险程度高且累积性强的复合污染场地[2-3].
重金属与多环芳烃复合污染是典型的无机-有机型复合污染,不仅来源广泛、危害性大,且物化性质稳定,会长期滞留在土壤和地下水中,难以去除,因此受到国内外诸多学者的关注. 王耀锋等[4]对我国焦化场地中PAHs和重金属进行污染评价,发现山西与河北地区的焦化场地危害程度最高;刘颖等[5]研究重复合污染场地中重金属与PAHs的空间分布特征和健康风险评估,以此提出各类污染物的风险管控值;杨悦锁等[6]提出,目前针对重金属与PAHs复合污染场地的修复方法主要有淋洗修复、生物修复和联合修复,但行之有效的方法较少;Wong等[7]认为石油与焦化行业的废水排放是土壤复合污染的重要原因. 重金属与PAHs在土壤环境中,经过迁移至某一区域后,相互作用相互影响,从而形成复合污染,会对人体健康和土壤环境产生更大的危害[8-9],因此研究重金属与PAHs的污染特征及风险评价能够为复合污染场地提供理论科学依据,具有重要的理论与实际意义[10].
本文以湖南某焦化厂遗留的重金属-多环芳烃复合污染场地为研究对象,通过场地环境调查和地质勘探,明确了该场地的地层结构和地下水特征;通过对场地不同功能区的不同深度土壤样品中重金属及多环芳烃含量测试,分析了场地主要污染物的含量与空间分布特征;通过对重金属与多环芳烃的相关性分析,阐述了其共存特征与来源;通过内梅罗综合污染指数法、质量基准法分别对重金属、多环芳烃进行生态风险评价,以期为该焦化场地的土壤污染治理和修复提供科学依据.
某焦化场地重金属与多环芳烃复合污染特征与评价
Co-contaminated characteristics and assessment of heavy metal and polycyclic aromatic hydrocarbons in a coking site
-
摘要: 调查与分析焦化遗留场地的土壤复合污染特征是土地安全再利用的基础. 以某焦化场地为例,采集0—5 m深度范围内的土壤样品,测定其中的重金属与PAHs含量,并运用反距离插值法分析场地重金属与PAHs的污染特征,采用内梅罗综合污染指数法评估焦化场地重金属的污染程度,质量基准法评价PAHs的生态风险. 结果表明:污染物分布的空间差异性明显,重金属与高环PAHs集中分布在0—1 m表层土壤,低环PAHs在杂填土与粉质粘土交界处呈现富集状态;重金属与PAHs的来源不同,但经迁移后在场地煤库、鼓冷车间及制冷站等区域共存形成复合污染;内梅罗综合污染指数评价表明,场地内气柜、煤库/煤棚、制冷站区域为中度—重度污染,质量基准法表明气柜、鼓冷车间、洗苯脱苯车间及煤库/煤棚处于中—高生态风险. 本研究结果能够为焦化场地的后续土壤修复工程及生产工艺优化提供参考.Abstract: Investigating and analyzing the compound pollution characteristics of coking site is the basis of land safe reuse. Taking a coking site as an example, soil samples at 0—5 m depth were collected to measure the content of the heavy metals and PAHs, The pollution characteristics of heavy metals and PAHs in the site are analyzed by using the inverse distance interpolation method, and the pollution degree of heavy metals in the coking site is evaluated by using the Nemero comprehensive pollution index method, the ecological risk of PAHs is evaluated by using the quality benchmark method. The results show that the distribution of pollutants has obvious spatial differences. Heavy metals and high molecular weight PAHs are concentrated in the 0—1 m surface soil, then the concentration of low molecular weight PAHs presents an enrichment state at the junction of miscellaneous fill and silty clay; The sources of heavy metals and PAHs are different, but they coexist and form compound pollution in coal bunker, blast cooling workshop and refrigeration station of the coking site after migration. The evaluation results of the Nemero comprehensive index show that they are moderately—severely polluted in gasholder, coal depot/coal shed, refrigeration station. The quality benchmark method shows that the gasholder, refrigeration station, coal depot/coal shed, drum cooling workshop, and benzene washing and debenzylation workshop are in medium—high ecological risk. The results of this research can provide guidance for the subsequent soil remediation project and production process optimization of coking site.
-
Key words:
- co-contaminated site /
- PAHs /
- heavy metal /
- distribution characteristics /
- pollution assessment.
-
表 1 土壤污染分级标准
Table 1. Soil pollution classification standard
单因子污染指数
Single pollution index污染水平
Pollution grade内梅罗综合污染指数
Nemerow comprehensive pollution index污染水平
Pollution gradePi≤1 清洁 P≤0.7 清洁 1<Pi≤2 轻度污染 0.7<P≤1.0 尚清洁 2<Pi≤3 中度污染 1.0<P≤2.0 轻度污染 Pi>3 重度污染 2.0<P≤3.0 中度污染 P>3.0 重度污染 表 2 土壤中多环芳烃效应区间中值(Ei)参考值[4]( mg·kg−1)
Table 2. Reference value of PAHs effect range median in soil(mg·kg−1)
多环芳烃
Polycyclic aromatic hydrocarbonsEi 多环芳烃
Polycyclic aromatic hydrocarbonsEi 萘(Nap) 2.10 苯并(a)蒽(BaA) 1.60 苊烯(Acy) 0.64 䓛(Chry) 2.80 苊(Ace) 0.50 苯并(b)荧蒽(BbF) 1.62 芴(Flu) 5.10 苯并(k)荧蒽(BkF) 1.62 菲(Phe) 1.50 苯并(a)芘(BaP) 1.60 蒽(Ant) 1.10 二苯并(a,h)蒽(DahA) 0.26 荧蒽(Fla) 0.54 苯并(g,h,i)苝(BghiP) 1.60 芘(Pyr) 2.60 茚并(1,2,3-cd)芘(InP) 1.60 表 3 质量基准法风险等级划分
Table 3. Soil average effect interval quotient QME risk classification
QME ≤0.1 0.1—0.5 0.5—1.5 ≥1.5 风险等级(Ecological risk) 无 低 中等 高 表 4 焦化厂遗留场地污染物含量分析
Table 4. Pollutants concentration in soil of coking site
土层
Soil layer污染物
Pollutant含量范围/(mg·kg−1)
C平均值/(mg·kg−1)
Cave变异系数
Coefficient of
variation筛选值/(mg·kg−1)
Cfil最大超标倍数
Maximum
exceedance上层(0—1 m) Pb 8.5—1190 703.2 0.83 400 1.98 As 2.96—956 123.6 2.92 40 22.9 Nap 0.12—28.6 3.74 1.77 25 0.15 Phe 9.2—128 55.23 1.1 5 24 BaA 0.28—8.5 1.86 1.95 5.5 0.55 BaP 0.6—6.4 2.18 1.46 0.55 10.6 中层(1—2 m) Pb 10.2—298 194.64 0.77 400 — As 1.23—800 249.88 2.32 40 7.95 Nap 0.09—47.7 8.3 1.86 25 0.91 Phe 6.3—35.2 12.45 1.34 5 6.04 BaA 0.3—6.6 1.61 2.26 5.5 — BaP 0.6—4.4 0.84 1.35 0.55 7.0 下层(2—3 m) As 8.47—126 94.9 0.72 40 2.15 Nap 0.1—255 48.2 0.98 25 9.2 Phe 0.2—266 80.1 1.79 5 52.2 BaA 0.13—4.9 1.33 2.0 5.5 — BaP 1.1—8.5 3.7 1.05 0.55 14.5 注:场地调查区域土壤属于红壤/黄棕壤,砷的筛选值为40 mg·kg−1.
Note: The soil in the site investigation area belongs to red soil/yellow brown soil, the filter value of As is 40 mg·kg−1.表 5 土壤多环芳烃相关性分析
Table 5. Correlation of polycyclic aromatic hydrocarbons in soil
因素
ElementPb As Nap Phe BaA BaP Pb 1 As 0.648** 1 Nap −0.274 −0.163 1 Phe −0.161 −0.177 0.940** 1 BaA −0.048 −0.135 0.420* 0.418* 1 BaP −0.220 −0.111 0.594** 0.548** 0.802** 1 **. P<0.01; *. P<0.05. 表 6 污染物主成分分析矩阵
Table 6. Component matrix of principal component analysis of pollutant
因素
Element初始因子荷载
Initial factor load旋转后因子荷载
Factor load rotationPC1 PC2 PC1 PC2 Pb 0.224 0.889 0.209 0.893 As −0.192 0.861 −0.207 0.858 Nap 0.894 0.085 0.892 0.100 Phe 0.872 0.010 0.871 0.025 BaA 0.744 −0.181 0.747 −0.169 BaP 0.862 0.019 0.862 0.034 特征值 2.944 1.573 2.072 1.793 累计方差贡献率% 49.06 75.28 40.06 75.28 表 7 场地土壤QME评价结果
Table 7. Soil QEM evaluation results of the site
项目
Project煤库/煤棚
Coal depot鼓冷车间
Drum cooling workshop制冷站
Refrigeration station气柜
Gas holder洗苯脱苯车间
Benzene washing and debenzylation workshopQME 15.69 18.91 3.36 1.42 21.07 污染程度 高生态风险 高生态风险 高生态风险 中生态风险 高生态风险 -
[1] 廖晓勇, 崇忠义, 阎秀兰, 等. 城市工业污染场地: 中国环境修复领域的新课题 [J]. 环境科学, 2011, 32(3): 784-794. LIAO X Y, CHONG Z Y, YAN X L, et al. Urban industrial contaminated sites: A new issue in the field of environmental remediation in China [J]. Environmental Science, 2011, 32(3): 784-794(in Chinese).
[2] 骆永明. 中国污染场地修复的研究进展、问题与展望 [J]. 环境监测管理与技术, 2011, 23(3): 1-6. doi: 10.3969/j.issn.1006-2009.2011.03.002 LUO Y M. Contaminated site remediation in China: Progresses, problems and prospects [J]. The Administration and Technique of Environmental Monitoring, 2011, 23(3): 1-6(in Chinese). doi: 10.3969/j.issn.1006-2009.2011.03.002
[3] 骆永明, 滕应. 中国土壤污染与修复科技研究进展和展望 [J]. 土壤学报, 2020, 57(5): 1137-1142. LUO Y M, TENG Y. Research progresses and prospects on soil pollution and remediation in China [J]. Acta Pedologica Sinica, 2020, 57(5): 1137-1142(in Chinese).
[4] 王耀锋, 何连生, 姜登岭, 等. 我国焦化场地多环芳烃和重金属分布情况及生态风险评价 [J]. 环境科学, 2021, 42(12): 5938-5948. doi: 10.13227/j.hjkx.202105239 WANG Y F, HE L S, JIANG D L, et al. Distribution and ecological risk assessment of polycyclic aromatic hydrocarbons and heavy metals in coking sites in China [J]. Environmental Science, 2021, 42(12): 5938-5948(in Chinese). doi: 10.13227/j.hjkx.202105239
[5] 刘颖, 周念清. 复合污染场地污染特征分析及健康风险评估 [J]. 同济大学学报(自然科学版), 2018, 46(7): 934-943. LIU Y, ZHOU N Q. Pollution characteristics and health risk of heavy metals and polycyclic aromatic hydrocarbons in a Co-contaminated site [J]. Journal of Tongji University (Natural Science), 2018, 46(7): 934-943(in Chinese).
[6] 杨悦锁, 陈煜, 李盼盼, 等. 土壤、地下水中重金属和多环芳烃复合污染及修复研究进展 [J]. 化工学报, 2017, 68(6): 2219-2232. YANG Y S, CHEN Y, LI P P, et al. Research progress on co-contamination and remediation of heavy metals and polycyclic aromatic hydrocarbons in soil and groundwater [J]. CIESC Journal, 2017, 68(6): 2219-2232(in Chinese).
[7] WONG M H, WU S C, DENG W J, et al. Export of toxic chemicals - A review of the case of uncontrolled electronic-waste recycling [J]. Environmental Pollution, 2007, 149(2): 131-140. doi: 10.1016/j.envpol.2007.01.044 [8] 沈国清, 陆贻通, 周培. 土壤环境中重金属和多环芳烃复合污染研究进展 [J]. 上海交通大学学报(农业科学版), 2005, 23(1): 102-106. SHEN G Q, LU Y T, ZHOU P. Advances of research on combined pollution of heavy metals with polycyclic aromatic hydrocarbons(PAHs) in soil environment [J]. Journal of Shanghai Jiao Tong University (Agricultural Science), 2005, 23(1): 102-106(in Chinese).
[9] 马佳燕, 马嘉伟, 柳丹, 等. 杭嘉湖平原水稻主产区土壤重金属状况调查及风险评价 [J]. 浙江农林大学学报, 2021, 38(2): 336-345. doi: 10.11833/j.issn.20950756.20200309 MA J Y, MA J W, LIU D, et al. Survey and risk assessment of soil heavy metals in the main rice producing areas in Hangjiahu Plain [J]. Journal of Zhejiang A & F University, 2021, 38(2): 336-345(in Chinese). doi: 10.11833/j.issn.20950756.20200309
[10] 朱岗辉, 孙璐, 廖晓勇, 等. 郴州工业场地重金属和PAHs复合污染特征及风险评价 [J]. 地理研究, 2012, 31(5): 831-839. ZHU G H, SUN L, LIAO X Y, et al. Combined pollution of heavy metals and PAHs and its risk assessment in industrial sites of Chenzhou City [J]. Geographical Research, 2012, 31(5): 831-839(in Chinese).
[11] 毛盼, 王明娅, 孙昂, 等. 某典型废弃硫酸场地土壤重金属污染特征与评价 [J]. 环境化学, 2022, 41(2): 511-525. doi: 10.7524/j.issn.0254-6108.2021071304 MAO P, WANG M Y, SUN A, et al. Heavy metal pollution characteristics and assessment in soil of a typical abandoned sulfuric acid site [J]. Environmental Chemistry, 2022, 41(2): 511-525(in Chinese). doi: 10.7524/j.issn.0254-6108.2021071304
[12] 武海霞, 马栋. 工业污染场地土壤中多环芳烃测定方法研究 [J]. 内江科技, 2015, 36(12): 35-36. doi: 10.3969/j.issn.1006-1436.2015.12.026 WU H X, MA D. Study on determination method of polycyclic aromatic hydrocarbons in contaminated site soil [J]. Nei Jiang Science & Technology, 2015, 36(12): 35-36(in Chinese). doi: 10.3969/j.issn.1006-1436.2015.12.026
[13] 吕占禄, 张金良, 张晗, 等. 生物质能电厂周边土壤中重金属元素污染特征及评价 [J]. 环境化学, 2020, 39(12): 3480-3494. LV Z L, ZHANG J L, ZHANG H, et al. Pollution characteristics and evaluation of heavy metal pollution in surface soil around the Biomass Power Plant [J]. Environmental Chemistry, 2020, 39(12): 3480-3494(in Chinese).
[14] 廖晓勇, 陈同斌, 武斌, 等. 典型矿业城市的土壤重金属分布特征与复合污染评价: 以“镍都”金昌市为例 [J]. 地理研究, 2006, 25(5): 843-852. doi: 10.3321/j.issn:1000-0585.2006.05.010 LIAO X Y, CHEN T B, WU B, et al. Mining urban soil pollution: Concentrations and patterns of heavy metals in the soils of Jinchang, China [J]. Geographical Research, 2006, 25(5): 843-852(in Chinese). doi: 10.3321/j.issn:1000-0585.2006.05.010
[15] LONG E R, MACDONALD D D, SMITH S L, et al. Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments [J]. Environmental Management, 1995, 19(1): 81-97. doi: 10.1007/BF02472006 [16] 刘庚, 毕如田, 张朝, 等. 某焦化场地苯并(a)芘污染空间分布范围预测的不确定性分析 [J]. 环境科学学报, 2013, 33(2): 587-593. doi: 10.13671/j.hjkxxb.2013.02.027 LIU G, BI R T, ZHANG C, et al. Uncertainty analysis on spatial distribution prediction of BaP in a coking plant site [J]. Acta Scientiae Circumstantiae, 2013, 33(2): 587-593(in Chinese). doi: 10.13671/j.hjkxxb.2013.02.027
[17] 徐源, 师华定, 王超, 等. 湖南省郴州市苏仙区重点污染企业影响区的土壤重金属污染源解析 [J]. 环境科学研究, 2021, 34(5): 1213-1222. doi: 10.13198/j.issn.1001-6929.2020.11.03 XU Y, SHI H D, WANG C, et al. Heavy metal pollution sources in soil affected by key pollution enterprises in Suxian District, Chenzhou City, Hunan Province [J]. Research of Environmental Sciences, 2021, 34(5): 1213-1222(in Chinese). doi: 10.13198/j.issn.1001-6929.2020.11.03
[18] 段友春, 梁兴光, 臧浩, 等. 日照市典型农用地土壤重金属来源分析及环境质量评价 [J]. 环境污染与防治, 2020, 42(11): 1410-1414,1429. doi: 10.15985/j.cnki.1001-3865.2020.11.019 DUAN Y C, LIANG X G, ZANG H, et al. Source analysis and environmental quality assessment of heavy metals in farmland soil in a typical area of Rizhao City [J]. Environmental Pollution & Control, 2020, 42(11): 1410-1414,1429(in Chinese). doi: 10.15985/j.cnki.1001-3865.2020.11.019
[19] 韩张雄, 万的军, 胡建平, 等. 土壤中重金属元素的迁移转化规律及其影响因素 [J]. 矿产综合利用, 2017(6): 5-9. doi: 10.3969/j.issn.1000-6532.2017.06.002 HAN Z X, WAN D J, HU J P, et al. Migration and transformation of heavy metals in soil and its influencing factors [J]. Multipurpose Utilization of Mineral Resources, 2017(6): 5-9(in Chinese). doi: 10.3969/j.issn.1000-6532.2017.06.002
[20] YANG J J, WANG S Q, GUO Z W, et al. Spatial distribution of toxic metal(loid)s and microbial community analysis in soil vertical profile at an abandoned nonferrous metal smelting site [J]. International Journal of Environmental Research and Public Health, 2020, 17(19): 7101. doi: 10.3390/ijerph17197101 [21] ZENG J Q, LUO X H, CHENG Y Z, et al. Spatial distribution of toxic metal(loid)s at an abandoned zinc smelting site, Southern China [J]. Journal of Hazardous Materials, 2022, 425: 127970. doi: 10.1016/j.jhazmat.2021.127970 [22] 孟祥帅, 吴萌萌, 陈鸿汉, 等. 某焦化场地非均质包气带中多环芳烃(PAHs)来源及垂向分布特征 [J]. 环境科学, 2020, 41(1): 377-384. doi: 10.13227/j.hjkx.201903142 MENG X S, WU M M, CHEN H H, et al. Vertical pollution characteristics and sources of polycyclic aromatic hydrocarbons in a heterogeneous unsaturated zone under a coking plant [J]. Environmental Science, 2020, 41(1): 377-384(in Chinese). doi: 10.13227/j.hjkx.201903142
[23] 李看看, 吴娟, 马东, 等. 表面活性剂对土壤中多环芳烃(PAHs)纵向迁移的影响 [J]. 环境化学, 2018, 37(7): 1545-1553. doi: 10.7524/j.issn.0254-6108.2017101301 LI K K, WU J, MA D, et al. Effects of surfactant on longitudinal migration of polycyclic aromatic hydrocarbons in soil [J]. Environmental Chemistry, 2018, 37(7): 1545-1553(in Chinese). doi: 10.7524/j.issn.0254-6108.2017101301
[24] 韩志刚. 多环芳烃在土壤中的老化和迁移行为研究[D]. 福州: 福建师范大学, 2009. HAN Z G. Aging and transport behavior of polycyclic aromatic hydrocarbons in soils[D]. Fuzhou: Fujian Normal University, 2009(in Chinese).
[25] 吴志远, 张丽娜, 夏天翔, 等. 基于土壤重金属及PAHs来源的人体健康风险定量评价: 以北京某工业污染场地为例 [J]. 环境科学, 2020, 41(9): 4180-4196. WU Z Y, ZHANG L N, XIA T X, et al. Quantitative assessment of human health risks based on soil heavy metals and PAHs sources: Take a polluted industrial site of Beijing As an example [J]. Environmental Science, 2020, 41(9): 4180-4196(in Chinese).
[26] 周艳, 陈樯, 邓绍坡, 等. 西南某铅锌矿区农田土壤重金属空间主成分分析及生态风险评价 [J]. 环境科学, 2018, 39(6): 2884-2892. ZHOU Y, CHEN Q, DENG S P, et al. Principal component analysis and ecological risk assessment of heavy metals in farmland soils around a Pb-Zn mine in southwestern China [J]. Environmental Science, 2018, 39(6): 2884-2892(in Chinese).
[27] 师荣光, 吕俊岗, 张霖琳. 天津城郊土壤中PAHs含量特征及来源解析 [J]. 中国环境监测, 2012, 28(4): 1-5. doi: 10.3969/j.issn.1002-6002.2012.04.001 SHI R G, LV J G, ZHANG L L. Content character and source analyses of PAHs in soils of Tianjin suburbs [J]. Environmental Monitoring in China, 2012, 28(4): 1-5(in Chinese). doi: 10.3969/j.issn.1002-6002.2012.04.001
[28] 崔政武, 王洋, 于锐, 等. 吉林省电厂周边农田土壤中多环芳烃含量特征及风险评价 [J]. 环境污染与防治, 2018, 40(7): 806-811. doi: 10.15985/j.cnki.1001-3865.2018.07.015 CUI Z W, WANG Y, YU R, et al. Content characteristics and risk assessment of PAHs in agricultural soils around power plants in Jilin Province [J]. Environmental Pollution & Control, 2018, 40(7): 806-811(in Chinese). doi: 10.15985/j.cnki.1001-3865.2018.07.015
[29] 李永霞, 刘燕, 王文刚, 等. 某钢铁企业表层土壤中多环芳烃含量特征与生态风险评价 [J]. 环境化学, 2017, 36(6): 1320-1327. doi: 10.7524/j.issn.0254-6108.2017.06.2016090802 LI Y X, LIU Y, WANG W G, et al. Concentration characteristic and ecological risk assessment of polycyclic aromatic hydrocarbons in the surface soils of a steel plant [J]. Environmental Chemistry, 2017, 36(6): 1320-1327(in Chinese). doi: 10.7524/j.issn.0254-6108.2017.06.2016090802
[30] 孔露露, 史明静, 梁晶晶, 等. 大港油田土壤中PAHs的组成特征及来源分析 [J]. 环境科学与技术, 2018, 41(5): 151-157. doi: 10.19672/j.cnki.1003-6504.2018.05.025 KONG L L, SHI M J, LIANG J J, et al. Concentration and origin of polycyclic aromatic hydrocarbons in the soil of dagang oil field [J]. Environmental Science & Technology, 2018, 41(5): 151-157(in Chinese). doi: 10.19672/j.cnki.1003-6504.2018.05.025
[31] 安永龙, 黄勇, 孙朝, 等. 北京通州某改造区土壤中PAHs的来源分析及风险评价 [J]. 水文地质工程地质, 2017, 44(5): 112-120. doi: 10.16030/j.cnki.issn.1000-3665.2017.05.18 AN Y L, HUANG Y, SUN Z, et al. Source apportionment and risk assessment of PAHs in soil from a renewal area in the Tongzhou District of Beijing [J]. Hydrogeology & Engineering Geology, 2017, 44(5): 112-120(in Chinese). doi: 10.16030/j.cnki.issn.1000-3665.2017.05.18
[32] 郝丽虹, 张世晨, 武志花, 等. 低山丘陵区焦化厂土壤中PAHs空间分布特征 [J]. 中国环境科学, 2018, 38(7): 2625-2631. doi: 10.3969/j.issn.1000-6923.2018.07.031 HAO L H, ZHANG S C, WU Z H, et al. Spatial distribution characteristics of PAHs in soil at hilly areal coking plant [J]. China Environmental Science, 2018, 38(7): 2625-2631(in Chinese). doi: 10.3969/j.issn.1000-6923.2018.07.031
[33] 周玉璇, 龙涛, 祝欣, 等. 重金属与多环芳烃复合污染土壤的分布特征及修复技术研究进展 [J]. 生态与农村环境学报, 2019, 35(8): 964-975. doi: 10.19741/j.issn.1673-4831.2018.0669 ZHOU Y X, LONG T, ZHU X, et al. Research progress on distribution and remediation technologies for the combined pollution of heavy metals and polycyclic aromatic hydrocarbons in soil [J]. Journal of Ecology and Rural Environment, 2019, 35(8): 964-975(in Chinese). doi: 10.19741/j.issn.1673-4831.2018.0669