CAJ | 학술논문

通过野外采样、室内分析和水培实验,研究了某废弃铀矿坑水中的土著水生植物大薸(Pistia stra-tiotes L.)和凤眼莲(Eichhornia crassipes)对铀矿坑水的原位修复能力。野外采样分析结果表明,大薸和凤眼莲对废弃铀矿坑水中的铀有极强的富集能力。废弃铀矿坑水中铀浓度在0.4~0.6 m g/L 之间,高出国家排放标准(GB 23727—2009)规定值(0.05 mg/L)的10倍左右。废弃铀矿坑水中土著水生植物大薸和凤眼莲根系平均铀含量分别为1015.40 mg/kg (干重)和504.87 mg/kg (干重)；富集系数分别为2071和1001。水培实验结果表明,大薸对铀矿坑水中铀的去除能力与植物生长期、生物量和覆盖水体面积呈正相关。生长后期(单株生物量鲜重≥100 g)的大薸、凤眼莲,投加量为100 g/L时,10 d可将铀矿坑水中铀浓度由1.93 mg/L 降至0.03 mg/L 以下,去除率达到98%以上。SEM-EDS结果表明,大薸和凤眼莲在酸性条件下与水体中的铀结晶矿化,生成纳米片状晶体堆簇在根系表面；在碱性条件下(接近废弃铀矿坑水的 pH 值时),未出现类似矿化结晶体。表明大薸和凤眼莲对于不同酸度的铀废水体系有不同的修复机理。
통과야외채양、실내분석화수배실험,연구료모폐기유광갱수중적토저수생식물대표(Pistia stra-tiotes L.)화봉안련(Eichhornia crassipes)대유광갱수적원위수복능력。야외채양분석결과표명,대표화봉안련대폐기유광갱수중적유유겁강적부집능력。폐기유광갱수중유농도재0.4~0.6 m g/L 지간,고출국가배방표준(GB 23727—2009)규정치(0.05 mg/L)적10배좌우。폐기유광갱수중토저수생식물대표화봉안련근계평균유함량분별위1015.40 mg/kg (간중)화504.87 mg/kg (간중)；부집계수분별위2071화1001。수배실험결과표명,대표대유광갱수중유적거제능력여식물생장기、생물량화복개수체면적정정상관。생장후기(단주생물량선중≥100 g)적대표、봉안련,투가량위100 g/L시,10 d가장유광갱수중유농도유1.93 mg/L 강지0.03 mg/L 이하,거제솔체도98%이상。SEM-EDS결과표명,대표화봉안련재산성조건하여수체중적유결정광화,생성납미편상정체퇴족재근계표면；재감성조건하(접근폐기유광갱수적 pH 치시),미출현유사광화결정체。표명대표화봉안련대우불동산도적유폐수체계유불동적수복궤리。
The field sampling, laboratory analysis and hydroponic solution culture experiments were conducted on the native aquatic plants,Pistia stratiotes L.and Eich-hornia crassipes in-situ repair ability of uranium mine pit water.The results of field sampling analysis show the strong enrichment of uranium from abandoned uranium mine pit water by Pistia stratiotes L.and Eichhornia crassipes.The uranium concentration range of abandoned uranium mine pit water is between 0.4 mg/L to 0.6 mg/L,which is about 10 times higher than the national emission standards of China.The mean uranium concentrations (dry weight)in roots of Pistia stratiotes L.and Eichhornia crassipes are 1 015.40 mg/kg and 504.87 mg/kg,and the enrichment coefficients are 2 071 and 1 001,respectively.The results of hydroponic solution culture experiments show that the uranium removal ability is closely relative to the growing period and fresh weight of per plant and the area of the plant covering water.100 g of Pistiastratiotes L.or Eich-hornia crassipes at the mature stage (fresh weight more than 100 g per plant)are grown in 1 L of uranium mine pit water with the initial concentration of uranium was 1.93 mg/L,after 10 days,the uranium concentration reduces to below the national emission standards of China,and the uranium removal rates are higher than 98%.SEM-EDS results show that a mass of uranium precipitates with nanometer sized schistose structures on the root surface of Pistia stratiotes L. and Eichhornia crassipes are formed at acidic conditions.But there are no similar crystals observed on the surface of Pistia stratiotes L.and Eichhornia crassipes at alkaline conditions.The present work suggests the different repair mechanisms of uranium-contaminated waste water by the Pistia stratiotes L.and Eichhornia crassipes between acidic and alkaline conditions.