37 5 2018 9 GeologicalScienceandTechnologyInformation Vol.37 No.5 Sep. 2018 doi:10.19509/j.cnki.dzkq.2018.0528. [J]. 201837(5):206-21. ab ab ab ab ( )a. ;b. 3007) : : ph Ec SO 2- HCO 3 - As / / : ; ; ; ; :X131.2 :A :1000-789(2018)05-0206-09 [1-2] As [15-19] (Ⅲ) As(Ⅴ) [3-5] : [6] ; (SO 2- NO 3 - ) 1 [7-9] ; [10-12] - 5100km 2 - [13] [121] 00 mm 7 [20] - [21] - :2018-03-0 : : (137225); (2016ACA167) : (1993 ) E-mail: yanyijun 23@163.com : (1979 ) E- mail:cug xxj@163.com
5 : 207 2 (7 m 7 m) ( 1) 20.5~22.5 m 2 18.35~195μg/L 2.7~26.2 m Fig.2 Locationsofthemonitoringwels 25.67~33μg/L [20] 1018.7m DR2800 0.5μm 2m 0.20.0.611.52.03.0 m TOC ( 2) ph 2 PW2 TOC Cl - SO 2- NO 3-2017 8 761CompactIC Ca 2+ Mg 2+ Na + K + IRISIntrepid 2d IXSP ICP-AES As 2d 7d 11d AFS-9700 TOC 3 Picarro TOC-CRDS 8d ±5% [22] 60cm 2cm ; 60~200cm 5cm Thi [23] ( 1) ( ) ph ORP Ec (S 2- Fe 2+ NH -N NO 2 - ) ph 1 ORP Ec HACH HQ Table1 Paralelchemicalextractionprocedureforsolid- 0-d 2h phasearsenic HACH 1 0.5mol /L NaClpH=8 2 h25 2 0.5mol /L ph=3 2 h25 3 0.1mol /L ph=3 2h25 0.2mol /L +0.1mol/L ph=3 2h25 3 1 Fig.1 Locationofthestudysite 3.1 PW2 2m HCO 3-Na
208 2018 ( 3) HCO 3-0~2m 37.56mg/L Cl - SO 2- ( ) Ca 2+ 21.067mg/L Na + Cl - SO 2- HCO 3 - Na + 237.38mg/L Mg 2+ Ca 2+ Mg 2+ 18.828.92 mg/l PW2 ph 7.95-171.8 mv PW2 3.2 38μg/L 10μg/LAs(Ⅲ) 5-a 0.20. 79% 0.6m 591d.636.336.52μg/L 1.01.52.0m 0.5~2.0μg/L 0 ~2m 10μg/ L As(Ⅲ)/As T 5-b As(Ⅲ)/As T As(Ⅴ) As(Ⅲ) As 3 (Ⅲ)/As T Fig.3 Piperdiagramofsoilporewaterinirrigationareaand As(Ⅲ ) As(Ⅴ ) groundwaterofpumpingwels As(Ⅲ)/As T Cl-Na( 3) Cl - SO 2- HCO - 3 Na + Mg 2+ Ca 2+ (b) Fig.5 VariationofAsconcentrations(a)andAs(Ⅲ)/As Tratio Fig. Variationoftheaverageconcentrationsofmainionsin (b)ofsoilporewaterduringtheirrigationpractice soilporewatersamplesduringtheirrigation 5 (a) As(Ⅲ)/As T
5 : 209 0~2m 10μg/L 3 m Ec 1.2~5.79mS/ ( 2) cm ( 6-b) Ec 1.83μg/L 100μg/L As(Ⅲ) / As(Ⅴ ) As / [26] (Ⅲ)As(Ⅲ) 3 m 3m SO 2- HCO 3 - As(Ⅲ) HPO 2- [27-28] As(Ⅲ)/As T SO 2- HCO 3 - As (V) As(Ⅲ) ( 7) As(Ⅲ) As(Ⅴ) SO 2- HCO 3-2 3.0m As(Ⅲ) SO 2- HCO 3 - Table2 VariationofAsconcentrationsof3.0 m phreatic waterduringtheirrigation SO 2- SO 2- As(Ⅴ) As(Ⅲ) [29] S-0 S1 - S-2 S-3 S- S-5 S-6 S-7 SO 2- HCO 3-1.83 15.69 15.53 228.9103.03120.01 75.21 71.79 As(Ⅲ) 1.67 12.8 1.90 / 8.59 91.26 50.39 51.2 As(Ⅴ) 0.15 2.85 0.62 / 18.3 28.75 2.83 20.37 3.3.2 As(Ⅲ)/AsT 0.99 0.82 0.96 / 0.82 0.76 0.67 0.72 3.3 [30] / 3.3.1 / ρ (TOC) ρ (As) ( 8-a) ph 7.33 CO 2 ~8.79 HCO 3 - ( 6-a) ρ ( HCO 3 - ) ρ (TOC) ( [2-25] ph 8-b) ( 9-a) 6 ph (a) Ec (b) Fig.6 RelationshipbetweenAsconcentrationsversuspH (a)ec(b)ofsoilporewater
210 2018 7 As(Ⅲ) As(Ⅴ) SO 2- HCO 3 - Fig.7 RelationshipsbetweenAs(Ⅲ) As(Ⅴ)concentrationsversusSO 2- HCO 3ofsoilporewater 8 TOC (a) HCO 3 - (b) Fig.8 RelationshipsbetweenTOCversusAsconcentrations(a)HCO - 3 (b)ofsoilporewater (Fe / (OH) 3 ) (FeOOH) 2O 3 ) SI
5 : 211 9 (a) Fe(OH) 3 (b)fe(ooh)(c)fe 2O 3 (d) Fig.9 RelationshipsbetweenAsconcentrationsversusFeconcentrations(a)andtheSIofFe(OH) 3 (b)feooh(c)fe 2O 3 (d) ( 9-b~ d) 50%~62% ρ ( As) 3. ( 10) 5% 0~0.1m 11
２１２ 地 质 科 技 情 报 ２０１８ 年 图 １０ 灌溉前后沉积物中总砷及各形态砷质量分数对比 Ｆｉｇ １０ Ｃｏｍｐａｒｉｓｏｎｏｆｄｉ ｆｆｅｒｅｎｔａｒｓｅｎｉｃｐｈａｓｅｓｏｆｓｅｄｉｍｅｎｔｓｂｅｆｏｒｅｔｈｅｉｒｒｉｇａｔｉｏｎａｎｄａｆｔｅｒｔｈｅｉｒｒｉｇａｔｉｏｎ 图 １１ 灌溉过程中非饱和带中砷的迁移转化机理 Ｆｉｇ １１ Ｓｃｈｅｍａｔｉｃｄｉａｇｒａｍ ｏｆａｒｓｅｎｉｃｍｉｇｒａｔｉｏｎａｎｄｔｒａｎｓｆｏｒｍａｔｉｏｎｉｎｔｈｅｕｎｓａｔｕｒａｔｅｄｚｏｎｅｄｕｒｉｎｇｔｈｅｉｒｒｉｇａｔｉｏｎ 为易被还原的无定 形 铁 氧 化 物 无 定 形 铁 氧 化 物 进 氧化物转化为无定 形 铁 氧 化 物 无 定 形 铁 氧 化 物 以 一步还原溶解 以吸附 共沉淀形式与之结合的砷被 及碳酸盐铁 溶 解 导 致 砷 的 释 放 但 仍 有 Ｏ２ 进 入 近 地表的非饱 和 带 使 Ｆｅ Ⅱ 被 氧 化 为 Ｆｅ Ⅲ 进 而 形成结 晶 态 铁 氧 化 物 Ａｓ Ⅲ 被 迅 速 氧 化 为 Ａｓ Ⅴ 以吸附 共沉淀形式被结晶态铁氧化物固定 释放进入水体中 同时 部分碳酸盐铁也被溶解导致 砷的释放 被释放的 Ａｓ Ⅴ 在还原环境下被还原为 Ａｓ Ⅲ Ａｓ Ⅲ 的迁移性比 Ａｓ Ⅴ 强很多 生成的 Ａｓ Ⅲ 向 下 迁 移 进 入 地 下 水 中 在 接 近 地 表 的 非 饱和带 灌溉使其还原环境变强 存在部分结晶态铁 灌溉 结 束 后 水 回 落 大 量 Ｏ２ 进 入 土 壤 孔 隙 中 导致土壤氧化 性 逐 渐 增 强 更 多 Ｆｅ Ⅱ 被 氧 化
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21 2018 chimicaacta199357(10):2251-2269. [25]FrostR RGrifinR A.EfectofpHonadsorptionofarsenic andseleniumfromlandfilleachatebyclay minerals[j].soil ScienceSocietyofAmericaJournal19771(1):53-57. [26]MercerK LTobiasonJE.Removalofarsenicfromhighionic strengthsolutions:efectsofionicstrengthphand pre- formedversusinsituformed HFO[J].EnvironmentalScience & Technology20082(10):3797-3802. [27]ZhaoH SRS.Competitiveadsorptionofphosphateandarse- nateongoethite[j].environmentalscience & Technology 200135(2):753-757. InfluenceofIrrigationPracticesonArsenicMobilization andtransformationintheunsaturatedzone YanYijun ab XieXianjun ab XiaoZiyi ab LiJunxia ab (a.schoolofenvironmentalstudies;b.statekeylaboratoryofbiogeologyand EnvironmentalGeologyChinaUniversityofGeosciences(Wuhan)Wuhan3007China) [28]RaduTSubaczJLJohnJ M Petal.Efectsofdissolved carbonateonarsenicadsorptionandmobility[j].environmen- talscience & Technology200539(20):7875-7882. [29]BurtonEDJohnstonSGBushR T.Microbialsulfidogenesis inferrihydrite-richenvironments:efectsoniron mineralogy andarsenic mobility[j].geochimicaetcosmochimica Acta 201175(11):3072-3087. [30]XieXWangYElisAetal.Multipleisotope(OSandC) approachelucidatestheenrichmentofarsenicinthegroundwa- terfromthedatongbasinnorthernchina[j].journalofhy- drology201398(18):103-112. Abstract:Inthisstudytheinfluencemechanismofirrigationpracticesonarsenicmobilizationandtrans- formationintheunsaturatedzoneisdiscussedbyfieldirrigationpractices.theresultsshowthatarsenic mobilizationintheunsaturatedzoneduringhigharsenicgroundwaterirrigationpracticesisinfluencedby multiplegeochemicalprocess.thearsenicconcentrationisafectedbythephthecompetitiveadsorption betweenso 2- andhco 3 - andtheredoxvolatilityintheunsaturatedzone.duringtheirrigationthesoilis intherelativelyreducingconditionstheironoxidemineralisdissolvedandthearsenicwhichiscombined withtheironoxidemineralduetocoprecipitationorsorptionisreleasedintosoilporewater.aftertheirri- gationthesoilcomesintotherelativelyoxidizingconditionsinwhichtheironoxidemineralprecipitates andthearsenicofsoilpore waterisfixedbytheironoxide mineralduetocoprecipitationorsorption. Thereforethechangeoftheredoxconditionwhichcausestheprecipitation/dissolutionoftheironoxide mineralisthemainreasonofarsenicmobilizationintheunsaturatedzoneinirrigationpractices. Keywords:arsenic;irrigation;unsaturatedzone;adsorption;redox