Screening of Indicators in Brown Rice Cadmium after Remediation of Cadmium Pollution in Farmland Soil
-
摘要: 目前农田土壤镉污染修复以降低糙米镉含量为标准,而忽略了其变化的关键性的土壤物理、化学及生物指标。基于此,采用方差分析、多元回归分析、通径分析、随机森林和结构方程模型等统计方法分析了土壤pH值、有机质、容重、阳离子交换量、速效养分、质地、微团聚体、酶活性、微生物数量等23个土壤指标对土壤有效态Cd和糙米Cd含量重要性排序。结果表明,总体上施用土壤调理剂提高了土壤pH值、容重和阳离子交换量,改变了土壤质地组成,增加了大粒级团聚体,并影响了微生物环境,有效降低了土壤有效态Cd和糙米Cd含量,但抑制了部分酶活性和微生物数量。通过逐步回归分析,表明土壤pH值和放线菌可以解释土壤有效态Cd 64.32%的变化,阳离子交换量、速效钾、有效磷和蔗糖酶可以解释糙米Cd 82.10%的变化;通径分析表明大粒径团聚体、有机质、黏粒、砂粒、放线菌和真菌对土壤有效态Cd和糙米Cd的直接效应较大;随机森林分析表明土壤pH值是影响土壤有效态Cd和糙米Cd含量的主导因素;结构方程模型表明糙米Cd含量主要受土壤pH值、有机质、阳离子交换量和有效磷的影响,土壤有效态Cd主要受土壤酶活性和微生物数量的影响。不同分析方法侧重点不同,总体上对糙米Cd含量影响较大的是pH值、阳离子交换量、有效磷和有机质等,对土壤有效态Cd含量影响较大的是pH值、放线菌和有机质等。Abstract: At present, the restoration of cadmium pollution in farmland soil is based on reducing the cadmium (Cd) content in brown rice, while ignoring the key soil physical, chemical and biological indicators of its change. Based on statistical methods including analysis of variance, multiple regression analysis, path analysis, random forest and structural equation model, the importance rankings of 23 soil indices to soil available Cd and brown rice Cd were analyzed. The results showed that the application of soil conditioners improved soil pH, bulk density and CEC, changed soil texture composition, increased the proportion of large-size aggregates, affected the microbial environment, and effectively reduced the contents of soil Cd and brown rice Cd, but inhibited a part of enzyme activities and the number of microorganisms. Through stepwise regression analysis, soil pH and actinomycetes explained 64.32% changes in soil available Cd, CEC, available potassium, available phosphorus (P) and invertase explained 82.10% changes in brown rice Cd. Path analysis showed that large-size aggregates, SOM, clay, sand, actinomycetes and fungi greatly directly affected soil available Cd and brown rice Cd. Random forests showed that soil pH was the dominant factor affecting soil available Cd and brown rice Cd. The structural equation model showed that the brown rice Cd was mainly affected by soil pH, SOM, CEC and available P, and the soil available Cd was mainly affected by soil enzyme activities and microbial quantity. Different analysis methods had different focuses. In general, pH, CEC, available P and SOM showed the greatest influences on the Cd content of brown rice. While, pH, actinomycetes and SOM had the greatest influences on soil available Cd.
-
Key words:
- Soil conditioner /
- Brown rice Cd /
- Soil index /
- Random forest /
- Structural equation model
-
图 2 随机森林对影响土壤有效态Cd和糙米Cd的自变量的重要性进行排序
X1:pH、X2:容重、X3:有机质、X4:阳离子交换量、X5:速效钾、X6:有效磷、X7:碱解氮、X8:粉粒、X9:黏粒、X10:砂粒、X11:微团聚体2 ~ 0.25 mm、X12:微团聚体0.25 ~ 0.05 mm、X13:微团聚体0.05 ~ 0.01 mm、X14:微团聚体0.01 ~ 0.005 mm、X15:微团聚体0.005 ~ 0.001 mm、X16:微团聚体 < 0.001 mm、X17:脲酶、X18:过氧化氢酶、X19:蔗糖酶、X20:酸性磷酸酶、X21:细菌、X22:真菌、X23:放线菌、Y1:土壤有效态Cd。下同。
Figure 2. Ranking variable importance of brown rice Cd and soil available Cd by random forest
图 3 土壤理化及生物指标对土壤有效态Cd和糙米Cd的通径分析
X1:pH、X2:容重、X3:有机质、X4:阳离子交换量、X5:速效钾、X6:有效磷、X7:碱解氮、X8:粉粒、X9:黏粒、X10:砂粒、X11:微团聚体2 ~ 0.25 mm、X12:微团聚体0.25 ~ 0.05 mm、X13:微团聚体0.05 ~ 0.01 mm、X14:微团聚体0.01 ~ 0.005 mm、X15:微团聚体0.005 ~ 0.001 mm、X16:微团聚体 < 0.001 mm、X17:脲酶、X18:过氧化氢酶、X19:蔗糖酶、X20:酸性磷酸酶、X21:细菌、X22:真菌、X23:放线菌、Y1:土壤有效态Cd。
Figure 3. Path analysis for the correlation between soil physical, chemical and biological indicators and soil available Cd and brown rice Cd
图 4 土壤理化及生物指标对土壤有效态Cd和糙米Cd的结构方程模型
模型中的R2均为国定效应解释的R2、X1:pH、X2:容重、X3:有机质、X4:阳离子交换量、X5:速效钾、X6:有效磷、X7:碱解氮、X17:脲酶、X18:过氧化氢酶、X19:蔗糖酶、X20:酸性磷酸酶、X21:细菌、X22:真菌、X23:放线菌、Y1:土壤有效态Cd、Y2:糙米Cd。
Figure 4. Structural equation model of the effects of soil physical, chemical and biological indicators on soil available Cd and brown rice Cd
-
[1] 环境保护部, 国土资源部. 全国土壤污染状况调查公报[R]. 北京: 环境保护部, 国土资源部, 2014. [2] Mohmmed A S, Kapri A, Goel R. Heavy metal pollution: source, impact, and remedies[J]. Environmental Pollution, 2011, 20(2): 1 − 28. [3] Akesson A, Barregard L, Bergdahl I A, et al. Non-renal effects and the risk assessment of environmental cadmium exposure[J]. Environmental Health Perspectives, 2014, 122(5): 431 − 438. doi: 10.1289/ehp.1307110 [4] Luo J S, Huang J, Zeng D L, et al. A defensin-like protein drives cadmium efflux and allocation in rice[J]. Nature Communications, 2018, 9(1): 645. doi: 10.1038/s41467-018-03088-0 [5] Khalid S, Shalid M, Nizai N K, et al. A comparison of technologies for remediation of heavy metal contaminated soils[J]. Journal of Geochemical Exploration, 2017, 182: 247 − 26. doi: 10.1016/j.gexplo.2016.11.021 [6] Wiszniewska A, Hanus F E, Muszynska E A. Natural organic amendments for improved phytoremediation of polluted soils: a review of recent progress[J]. Pedosphere, 2016, 26(1): 1 − 12. doi: 10.1016/S1002-0160(15)60017-0 [7] Sun Y B, Sun G H, Xu Y M, et al. Evaluation of the effectiveness of sepiolite, bentonite, and phosphate amendments on the stabilization remediation of cadmium-contaminated soils[J]. Journal of Environmental Management, 2016, 166: 204 − 210. [8] 冉洪珍, 郭朝晖, 肖细元, 等. 改良剂连续施用对农田水稻Cd吸收的影响[J]. 中国环境科学, 2019, 39(3): 223 − 229. [9] Yan B H, Dao Y H, Qi H Z, et al. A three-season field study on the in-situ remediation of Cd-contaminated paddy soil using lime, two industrial by-products, and a low-Cd-accumulation rice cultivar[J]. Ecotoxicology and Environmental Safety, 2017, 136: 135 − 141. doi: 10.1016/j.ecoenv.2016.11.005 [10] Amanullah M A, Wang P, Li R H, et al. Immobilization of lead and cadmium in contaminated soil using amendments:a review[J]. Pedosphere, 2015, 25(4): 555 − 568. doi: 10.1016/S1002-0160(15)30036-9 [11] 李 心, 林大松, 刘 岩, 等. 不同土壤调理剂对镉污染水稻田控镉效应研究[J]. 农业环境科学学报, 2018, 37(7): 1511 − 1520. doi: 10.11654/jaes.2018-0802 [12] 陈立伟, 杨文弢, 周 航, 等. 土壤调理剂对土壤-水稻系统Cd、Zn迁移累积的影响及健康风险评价[J]. 环境科学学报, 2018, 38(4): 1635 − 1641. [13] 余 志, 陈 凤, 张军方, 等. 锌冶炼区菜地土壤和蔬菜重金属污染状况及风险评价[J]. 中国环境科学, 2019, 39(5): 296 − 304. [14] 王 涛, 李惠民, 史晓燕. 重金属污染农田土壤修复效果评价指标体系分析[J]. 土壤通报, 2016, 47(3): 725 − 729. [15] 杨梦丽, 叶明亮, 马友华, 等. 基于重金属有效态的农田土壤重金属污染评价研究[J]. 环境监测管理与技术, 2019, 31(1): 13 − 16. [16] 宋 乐, 韩占涛, 张 威, 等. 改性生物质电厂灰钝化修复南方镉污染土壤及其长效性研究[J]. 中国环境科学, 2019, 39(1): 228 − 236. [17] 吴霄霄, 米长虹, 吴 昊, 等. 镉污染稻田修复效果评估指标体系的构建[J]. 农业环境科学学报, 2019, 38(7): 1498 − 1505. doi: 10.11654/jaes.2018-1604 [18] 周利军, 武 琳, 林小兵, 等. 土壤调理剂对镉污染稻田修复效果[J]. 环境科学, 2019, 40(11): 5098 − 5106. [19] 王湘徽, 郭中豪. 一种重金属污染晶化包封稳定化剂及其使用方法[P]. 中国专利: ZL20121021001.3, 2012 - 10 - 17. [20] 柳开楼, 熊华荣, 胡惠文, 等. 特贝钙土壤调理剂对红壤旱地花生产量和阻控土壤酸化的影响[J]. 广东农业科学, 2017, 44(5): 93 − 98. [21] Li Z W, Li L Q, Pan G X, et al. Bioavailability of Cd in a soil-rice system in China: Soil type versus genotype effects[J]. Plant and Soil, 2005, 271(1-2): 165 − 173. doi: 10.1007/s11104-004-2296-7 [22] 徐 磊, 周 静, 梁家妮, 等. 巨菌草对Cu、Cd污染土壤的修复潜力[J]. 生态学报, 2014, 34(18): 5342 − 5348. [23] 韩 雷, 陈 娟, 杜 平, 等. 不同钝化剂对Cd污染农田土壤生态安全的影响[J]. 环境科学研究, 2018, 31(7): 1289 − 1295. [24] Lorenz N, Hintemann T, Krama R, et al. Response of microbial activity and microbial community composition in soils to long-term arsenic and cadmium exposure[J]. Soil Biology and Biochemistry, 2006, 38(6): 1430 − 1437. doi: 10.1016/j.soilbio.2005.10.020 [25] 武 琳, 林小兵, 刘 晖, 等. 土壤调理剂对Cd污染农田土壤生物因子、有效态Cd及糙米Cd的影响[J]. 环境生态学, 2020, 2(4): 78 − 84. [26] Zhang J R, Li H Z, Zhou Y Z, et al. Bioavailability and soil to crop transfer of heavy metals in farmland soils: A case study in the Pearl River Delta South China[J]. Environmental Pollution, 2018, 235: 710 − 719. doi: 10.1016/j.envpol.2017.12.106 [27] 周 航, 周 歆, 曾 敏, 等. 2种组配改良剂对稻田土壤重金属有效性的效果[J]. 中国环境科学, 2014, 34(2): 437 − 444. [28] Wang A S, Angle S, Chaney R L, et al. Soil pH effects on uptake of Cd and Zn by Thlaspi caerulescens[J]. Plant and Soil, 2006, 281(1/2): 325 − 337. [29] 王梦梦, 何梦媛, 苏德纯. 稻田土壤性质与稻米镉含量的定量关系[J]. 环境科学, 2018, 39(4): 1918 − 1925. [30] 文 炯, 李祖胜, 许望龙, 等. 生石灰和钙镁磷肥对晚稻生长及稻米镉含量的影响[J]. 农业环境科学学报, 2019, 38(11): 2496 − 2502. doi: 10.11654/jaes.2019-0419 [31] 林大松, 徐应明, 孙国红, 等. 土壤pH、有机质和含水氧化物对镉、铅竞争吸附的影响[J]. 农业环境科学学报, 2007, 26(2): 510 − 515. doi: 10.3321/j.issn:1672-2043.2007.02.020 [32] 柴世伟, 温琰茂, 张云霓, 等. 广州郊区农业土壤重金属含量与土壤性质的关系[J]. 生态与农村环境学报, 2004, 20(2): 55 − 58. doi: 10.3969/j.issn.1673-4831.2004.02.013 [33] 施晓东, 常学秀. 重金属污染土壤的微生物响应[J]. 生态环境, 2003, 12(4): 498 − 499. [34] 韩桂琪, 王 彬, 徐卫红, 等. 重金属Cd、Zn、Cu、Pb复合污染对土壤微生物和酶活性的影响[J]. 水土保持学报, 2010, 24(5): 238 − 242. [35] Roosens N, Verbruggen N P, Ximenez E P, et al. Natural variation in cadmium tolerance and its relationship to metal hyperaccumulation for seven populations of Thlaspi caerulescens from western Europe[J]. Plant Cell & Environment, 2010, 26(10): 1657 − 1672. [36] 邢 金, 峰仓龙, 任静华. 重金属污染农田土壤化学钝化修复的稳定性研究进展[J]. 土壤, 2019, 51(2): 224 − 234. [37] 胡红青, 黄益宗, 黄巧云, 等. 农田土壤重金属污染化学钝化修复研究进展[J]. 植物营养与肥料学报, 2017, 23(6): 1676 − 1685. doi: 10.11674/zwyf.17299 [38] 陈同斌, 庞 瑞, 王佛鹏, 等. 桂西南土壤镉地质异常区水稻种植安全性评估[J]. 环境科学, 2020, 41(4): 1855 − 1863. [39] 吴霄霄, 曹榕彬, 米长虹, 等. 重金属污染农田原位钝化修复材料研究进展[J]. 农业资源与环境学报, 2019, 36(3): 253 − 263. [40] 孙丽娟, 秦 秦, 宋 科, 等. 镉污染农田土壤修复技术及安全利用方法研究进展[J]. 生态环境学报, 2018, 27(7): 1377 − 1386.