| Rice is the main necessary food in Hunan province.But,with the rapid development of economy,the Xiangjiang River has been polluted by mining industry,agriculture and three industrial wastes,which leads to the pollution of the soils and rice around of Xiangjiang.And this restrict the yield of rice,and threat the safety of rice.At the same time,heavy metals can enter into our body throuth the way of water-soil-rice-human body,which has a high ecological risk and hurts a lot. At present,the health problem caused by heavy metals has become hot issue.The exisiting research such as the exploitation of soil conditioner did not involve Y1 hybrid rice.And,when screening the fine varieties,there is not enough reserches about multiple rice species and heavy metal in Wangcheng district.And also,the process mode of how to decrease heavy metal in Huanghuazhan rice is rarely studyed.Aiming at these problems,this study analysis the uptake and distribution of heavy metal of rice,the pollution assessment of heavy metals,the filtration of low accumulation heavy metal varieties,and extract starch rice with alkali treatment.(1)Uptake and distribution of Pb and Cd by hybrid rice in soils.Atomic absorption spectrometer was used to detect the content of heavy metal in 100 hybrid rice and soil,statistical results showed that,in common red soil,the distribution of Pb in each part of rice was 94.20% in root,3.10% in stem and leaf,1.90% in cover,0.80% in unpolish rice,the distribution of Cd in each part of rice was 54.00% in root,21.60% in stem and leaf,13.00% in cover,11.40% in unpolish rice;In red soil with lime,the distribution of Pb in each part of rice was 95.50% in root,4.00% in stem and leaf,0.48% in cover,0.02% in unpolish rice,the distribution of Cd in each part of rice was 75.10% in root,17.70% in stem and leaf,7.10% in cover,0.10% in unpolish rice.This explained that the enrichment capacity in two kinds of soils was root>stem and leaf>cover>unpolish rice.Lime in soil can decrease the accumulation of Pb and Cd in unpolished rice to security standard.(2)The contamination status and health risk assessment of 7 kinds of heavy metals was researched in round rice and soil.ICP-MS,single factor pollution index,AHP was used to detect 150 round rice samples in 5 villages and towns in Wangcheng district,statistical results showed that,in unpolished rice,single factor pollution index of Cd,Num.8 of Jiaxing in order was Gaotangling (16.71)>Xingcheng town (13.09)>Xinkang village (10.76)>Qiaokou town (8.90)>Jinggang (0.75),Num.5 of Tefengyou was Gaotangling (15.98)>Xingcheng town (14.09)>Xinkang village (10.65)>Qiaokou town (8.71)>Jinggang town (0.83);single factor pollution index of inorganic As,Num.8 of Jiaxing in order was Gaotangling (4.10)>Xingcheng town (3.98)>Xinkang village (3.15)>Qiaokou town (2.67)>Jinggang town(1.56),Num.5 of Tefengyou was Gaotangling (4.01)>Xingcheng town (3.78)>Xinkang village (3.25)>Qiaokou tow (2.85)>Jinggang town (1.61);The single factor pollution index of Pb,Zn,Cu,Hg and Cr were less than 1.(3)The filtration of low accumulation heavy metal varieties.ICP-MS,Nemerow were used to detect the content of heavy metal in 150 hybrid rice samples.Statistical results showed that, the Nemerow index in order was Guyou929(3.45)> Shenyou 9588(3.21)>Yuanyou285(3.03)>Num.8 of Chuanxiang(3.02)>Qingyoul09(3.02)>Num.8 of Q you(2.93)>T you 118(2.92)>II you 416(2.88)>Num.6 of Q you (2.78)>Num.2O7 of H28(2.75)>T you 618(2.74)>Zhunliangyou 527 (2.67)>Liangyou 527(2.64)>Xieyou 716(2.62)>Num.8 of Zhongnanyou (2.60)>Shenliangyou 5814 (2.59)>Num.lof Y liang you(2.53)>Xiang you 66 (2.52)>Liang you 0293 (2.51)>Jinshan you 2155(2.50)>T227 (2.45)>Xiangfeiyou 8118 (2.40)>Yue you 6135 (2.40)>H28 you 9113(2.22)>T you 272(1.99).The results showed that the low accumulation rice varieties of Pb,Cd and inorganic As are T you 272,H28 you 9113,T you 227,Xiangfeiyou 8118,Jinshanyou 2155,Liangyou 0293,Xiangyou 66,Num.lof Y liangyou,and Yueyou 6135.(4)The content and distribution of Cd in Huanghuazhan rice and the influenceof alkali treatment.Stainless steel was used to strip 150 unpolished rice,alkali treatment was used to extract starch rice,and atomic absorption spectrometer was used to detect the content of heavy metal,statistical results showed that,the average proportion of Cd in rice bran,embryo,endosperm respectively are 31.2%,18.9% and 49.9%.The content of Cd in emdosperm increase with the total content of unpolished rice.But the degree in emdosperm is greater than rice bran and embryo.The content of Cd in rice was reduced 85%,and under 0.20mg/kg after alkaline process. |
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