Current and promising technologies to reduce cadmium contamination in rice. Satoru Ishikawa, Tomoyuki Makino, and Masaharu Murakami,

Transcription

1 Current and promising technologies to reduce cadmium contamination in rice Satoru Ishikawa, Tomoyuki Makino, and Masaharu Murakami,

2 Heavy metal pollution in monsoon Asia Country Origin Element Place Reference India Irrigation Pb, Ni, Cu, China Korea Mine, irrigation, Industry Mine, Industry, As, Cr, Hg, Pb As,, Cu, Pb, Zn, Hg Titagarh, West Bengal Hunan, Yunnan, Guangdong, Guizhou province Dongjeong Taiwan Mine, Industry, Pb Taoyuan Thailand Mine, Industry, Zn Malaysia Fertilizer Zn, Cu, Cr, Mae Sot District, Tak Cameron Highlands Sinha et al., 2006 Wong et al., 2002 Chung et al., 2005 Chen 1991 Simmons et al. 2005, 2008 Khairiah et al., 2006 Philippines Mine (irrigation) Hg Naboc area Appleton et al., 2006 Viet Nam Mine As, Cu Dai Tu district Ngoc et al., 2009

3 Designated sites for soil dressing in Japan (2008) (Main cause of pollution in paddy fields) Mine wastes have flowed into rivers and then into paddy fields as irrigation water. (Domestic criterion of in Japan) - 1 mg kg -1 of brown rice (1970) 0.4 mg kg -1 of rice (polished and unpolished rice) (2011) (Survey on grain level in Japan ) 0.3 % of total samples > 0.4 mg kg -1 (n=37,250 MAFF 2002) (Potentially low -contaminated area ) 40,000 ha

4 µg kg -1 body weight per week Provisional Tolerable Weekly Intake (PTWI) : 7.0µg kg -1 body weight per week Total diet : 3.0µg kg -1 body weight per week The others Fishes and shellfishes Vegetables and sea weeds Brightly colored vegetables Pulse and its products Wheat and tuber Provisional Tolerable Monthly Intake (PTWI) : 25 µg kg -1 body weight per month Rice and rice products Dietary intake of for the Japanese people (2004)

5 Countermeasures for reducing concentration in rice Present techniques Promising techniques Soil dressing Soil washing Submerged conditions Phytoextraction Development of low- rice

6 Promising techniques for reducing contamination in rice - Soil washing - Soil washing is a mechanical process that uses extracting chemicals to remove hazardous metals from soils into aqueous solution. Conceptual diagram of on-site soil washing 1Chemical washing 2Water washing 3Wastewater treatment Extraction of soil by FeCl 3 Removing residual and Cl in the paddy water Removing in the wastewater by chelating material FeCl 3 Paddy water Mixing Soil sedimentation 3 2 Water Mixing Soil sedimentation 3 Water treatment Treated water removal Chelating compliance with environmental standards Discharge

7 On-site process of soil washing 1Application of washing chemicals 2Mixing (Extraction of ) 3Sedimentation and drainage 4Treatment of wastewater 5Discharge of treated wastewater 6 Water washing Makino et al. (2006, 2007) Environmental Pollution Makino et al. (2008) Chemosphere

8 Soil- content (mg/kg) Unwashed plot Washed plot Toyama Soil 70% down Fukuoka Changes of soil content with the soil washing. Changes of rice- and - yield with the soil washing. On site washing is effective to remove from soils and rice. Brown rice yield (t ha -1 ) concentration (mg/kg) Unwashed plot Washed plot Nagano Toyama Fukuoka Unwashed plot Washed plot Rice yield Nagano Toyama Fukuoka Rice

9 Promising techniques for reducing contamination in rice - Phytoextraction - Phytoextraction is a kind of phytoremediation that use plants to remove the heavy metals from soils. Genotypic variation in accumulation in rice Shoot concentration (mg kg- 1 ) Jarjan Anjana Dhan Choko-koku 0 WRC01 WRC02 WRC03 WRC04 WRC05 WRC06 WRC07 WRC09 WRC10 WRC11 WRC12 WRC13 WRC14 WRC15 WRC16 WRC17 WRC18 WRC19 WRC20 WRC21 WRC22 WRC23 WRC24 WRC25 WRC26 WRC27 WRC28 WRC29 WRC30 WRC31 WRC32 WRC33 WRC34 WRC35 WRC36 WRC37 WRC38 WRC39 WRC40 WRC41 WRC42 WRC43 WRC44 WRC45 WRC46 WRC47 WRC48 WRC49 WRC50 WRC51 WRC52 WRC53 WRC55 WRC57 WRC58 WRC59 WRC60 WRC61 WRC62 WRC63 WRC64 WRC65 WRC66 WRC67 WRC68 WRC97 WRC98 WRC99 WRC100 Koshihik Sasanis Akitako Hitome Choko- High accumulating cultivars were selected for phyto-extracting from the paddy fields in Japan.

10 Physiological process of rice accumulation grain Shoot Grain concentration (mg kg -1 ) polluted soil Root uptake Grain A B C Xylem loading Shoot concentration (mg kg -1 ) Shoot A B C Xylem Soil concentration : 1.8 mg kg -1 (0.1 M HCl extractable) Xylem concentration (mg L -1 ) A:Nipponbare (Low - cv.) B: Jarjan (High- cv.) C:Anjana Dhan (High- cv.) A B C Root concentration (mg kg -1 ) Root A B C varieties

11 A gene controlling shoot accumulation (OsHMA3) Shoot Low -accumulating cultivars Root cell OsHMA3 Vacuole xylem High -accumulating cultivars Root cell Shoot OsHMA3 Vacuole xylem Miyadate et al. New Phytol. (2011), Ueno et al. PNAS (2010)

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13 Murakami et al. (2009) Environ Sci Technol 43,

14 Systematic phytoextraction for -contaminated paddy soils by high- accumulating rice 2)Whole crop harvester 1) Cultivation of high- accumulating rice under drained conditions 3) On-site drying 5) Recovery of takeout 4) Incineration (or bioethanol) Murakami et al. (2009) Environ Sci Technol 43, Arao et al. (2010) Paddy Water Environ, 8,

15 Promising techniques for reducing contamination in rice - Development of low rice - Ion-beam Koshihikari (M1 seeds) M1 plants M2 seeds analysis by ICP-MS Grain harvest of each plant Cultivation of 3,000 M2 Plants grown in polluted soil in pots

16 Screening result 600 Maximum level (0.4 mg kg -1 ) Koshihikari (WT) lcd-kmt1 lcd-kmt2 lcd-kmt3 Frequency Grain concentration (mg kg -1 ) lcd-kmt: low cadmium koshihikari mutant

17 Field trials on uptake in lcd-kmt1 rice Grain concentration (mg kg -1 ) Grain WT lcd-kmt ND Field A Field B Field C ML The lcd-kmt lines show nearly -free in their grains. Straw concentration (mg kg -1 ) Straw WT lcd-kmt Field A Field B Field C Soil concentration (mg kg -1 ) Field A: 1.35 Field B: 1.21 Field C: 0.35

18 Agronomic traits of lcd-kmt1 line 20cm WT kmt1 WT lcd-kmt1 5mm WT lcd-kmt1 Grain yield (t ha -1 ) a WT a lcd-kmt1 Eating quality (Score value) a WT a lcd-kmt1

19 (Ishikawa S. et al. submitted) Genetic mechanism of the decreased uptake in lcd-kmt lines (Mutation of OsNramp5 gene) Koshihikari (WT) Root cell Shoot OsNramp5 OsHMA3 Vacuole xylem lcd-kmt1, lcd-kmt2, lcd-kmt3 Root cell OsNramp5 OsHMA3 Vacuole xylem

20 Summary We developed three new technologies (soil washing, phyto-extraction, and low- rice) for reducing rice contamination. All techniques are very reliable and would be applicable to other countries in monsoon Asia. If you have very interested in these techniques and obtain more detail, please contact us. Contact persons: Soil washing Tomoyuki makino Phytoextraction Masaharu Murakami Low- rice Satoru Ishikawa