非或低镉污染稻田不同品种稻米镉含量调查

Cadmium in different rice cultivars in soil with or without light contamination

目的研究在非(或低)镉污染土壤中27个水稻品种稻米镉含量。方法于2014年4—9月,分别在四川省彭州市2个村选择3块试验田(基地1、2、3),采集土壤和稻米样品,检测土壤pH值、镉(各形态)含量及其风险程度,并测定稻米镉含量。结果基地1、2、3土壤镉含量分别为(0.31±0.09)、(0.22±0.03)、(0.38±0.05)mg/kg,pH值分别为4.61±0.2、5.33±0.3、5.97±0.4;土壤镉的污染指数的顺序依次为基地3(1.27)>基地1(1.03)>基地2(0.73),基地1、3为低风险污染程度土壤,基地2为无风险污染程度土壤。3个基地镉形态的构成比由高至低依次均为弱酸提取态(36.8%~58.7%)>可还原态(22.9%~25.3%)>可氧化态(7.1%~14.1%)>残渣态(11.3%~25.0%)。其中,生物可利用态比例(弱酸提取态+可还原态+可氧化态)的大小顺序为基地1>基地2>基地3。从27个试验品种看,盐粳11号、深两优5814、协优336、蓉18优188、D优158禾、中优31、B优817、泸优908、川江优527、禾优6号、D优128、辐优151、宜香99E-4、Q优6号、硕丰2号、冈优900、中9优1254共17个品种稻米中镉含量依次为基地1>基地2>基地3,泸优9803、川丰6号、蓉18优198、宜香3728、龙优8号、冈优177、天龙8优177共7个品种稻米中镉含量为基地1、2>基地3,富优1号、川香425、中优85共3个品种稻米中镉含量为基地1>基地2、3,差异均有统计学意义(P<0.05)。结论对于非(或低)镉污染稻田土壤,稻米镉污染除与土壤镉污染程度相关外,与土壤pH和水稻品种也有重要关联。

Objective To know the cadmium（Cd） concent of 27 rice cultivars from uncontaminated or lightly cadmium-contaminated paddy fields. Methods Cultivation test of 27 rice cultivars were performed in three experimental plot（base1,2,3）, with or without low Cd contamination in soil,selected from two counties in Pengzhou,Sichuan, from April to September in2014.Soil and harvested rice cultivars were sampled for determination of p H,Cd（speciation） concentration in soil and estimation on their environmental risk,as well as determination of Cd concentration in rice. Results The Cd levels were（0.31±0.09）,（0.22±0.03）,（0.38±0.05） mg/kg, p H 4.61, 5.33 and 5.97 in soils of Base 1,Base 2, Base 3, respectively, Base 1 [index of Cd pollution（PCd： 1.03）] and Base 3（PCd： 1.27） revealed low risk, Base 2（PCd： 0.73） no risk.The average proportion of different speciation of Cd in the three bases ranked as： acid extractable（36.8%-58.7%）〉reducible（22.9%-25.3%）〉oxidizable（7.1%-14.1%）〉residual（11.3%-25.0%）.The average proportion of bioavailable Cd,including acid extractable, reducible, and oxidizable,ranked as：Base 1 〉 Base 2 〉 Base 3.The Cd levels in 17 rice cultivars,such as Yanjing11, Shenliangyou5814, Xieyou336,Rong18 you188, D you158 he, Zhongyou31, B you817, Luyou908, Chuanjiangyou 527, Heyou No.6, D you128, Fuyou151,Yixiang 99 E-4, Q you No.6, Shoufeng No.2, Gangyou900, and Zhong9 you1254, ranked as：Base 1 〉Base 2 〉Base 3; And in other seven rice cultivars,such as Luyou9803, Chuanfeng No.6, Rong18 you 198, Yixiang3728, Longyou No.8, Gangyou177, and Tianlong8 you 177 ranked as：Base 1, 2 〉 Base 3;While in rest three rice cultivars,such as Fuyou No.1, Chuanxiang425, and Zhongyou85 ranked as Base 1 〉 Base2, 3; The regional difference had statistical significance（P 〈0.05）. Conclusion In the tested paddy soil with or without low Cd contamination, Cd contamination in rice is highly related to levels of Cd, p H in soil and rice cultivars.