Total arsenic in rice milk

Rice milk and its by-products were tested for total arsenic concentration. Total arsenic concentration was determined using graphite-furnace atomic absorption spectrometry. The arsenic concentrations ranged from 2.7 ± 0.3 to 17.9 ± 0.5 µg L^?1. Rice milk and its by-products are not clearly defined as food, water or milk substitute. The US Environmental Protection Agency (EPA), the European Union (EU) and the World Health Organization (WHO) have set a level of 10 µg L^?1 for total arsenic concentrations in drinking water. The EU and the US regulatory agencies do not provide any guidelines on total arsenic concentrations in foods. This study provides us with a starting point to address this issue in the State of Mississippi, USA.     

稻米中总砷及无机砷含量的测定与分析

采用氢化物原子荧光光度法测定13份稻米样品中的总砷和无机砷含量,结果表明：所测稻米样品中均检出总砷与无机砷,总砷含量范围为0.06~0.20 mg/kg,无机砷含量范围为0.039~0.150 mg/kg,无机砷占总砷的含量为50.0%~93.1%,无机砷含量在国家限量卫生标准以内;未冲洗大米样品中总砷含量仅为糙米的72.7%~90.0%,无机砷含量为糙米的62.7%~87.7%;多次冲洗的大米样品中总砷含量仅为未冲洗大米的75.0%~91.7%,无机砷含量为83.0%~93.6%。提高加工精度和用水淘洗均能在一定程度上降低总砷与无机砷的含量,减轻人们食用后对身体的危害。     

粳稻谷中总砷和无机砷含量的测定及分布情况

本文采用ICP-MS法和LC-AFS法分别测定粳稻谷中的总砷和无机砷含量.结果表明:总砷在0?10 ng/mL的浓度范围内呈良好的线性关系,检出限为0.020 7 ng/mL;As3+和As5+在0?50 ng/mL的浓度范围内呈良好的线性关系,As3+检出限为0.24 ng/mL,As5+检出限为0.44 ng/mL...     

测定稻谷中无机砷的方法探讨

应用AF7500双道氢化物-原子荧光光度计对稻谷中的无机砷进行测定.在酸性条件下,无机砷和硼氢化钾与酸产生的活性氢反应,生成氢化物气体,以氩气为载体导入石英炉中,通过能量跃迁放出的确荧光强度与砷舍量成正比结果表明,该方法准确性好,灵敏度高,适用于稻谷中无机砷的测定.     

Total and inorganic arsenic in rice and rice bran purchased in Thailand

Concentrations of total and inorganic arsenic were determined in 180 samples of polished and brown rice of three rice types, namely white, jasmine, and sticky, and 44 samples of rice bran from these three rice types purchased in Thailand. Concentrations (expressed in nanograms per gram) of inorganic arsenic in polished white, jasmine, and sticky rice were 68.3 ± 17.6 (with a range of 45.0 to 106), 68.4 ± 15.6 (41.7 to 101), and 75.9 ± 24.8 (43.5 to 156), respectively, while those in the three brown rice samples were 124 ± 34.4 (74.5 to 193), 120 ± 31.6 (73.1 to 174), and 131 ± 35.6 (78.0 to 188), respectively. Inorganic arsenic concentrations (expressed in nanograms per gram) in rice bran produced from the three rice types were 633 ± 182 (375 to 919), 599 ± 112 (447 to 824), and 673 ± 195 (436 to 1,071), respectively. Rice bran contained concentrations of total and inorganic arsenic approximately seven and nine times higher, respectively, than those found in the corresponding polished rice. The levels of inorganic arsenic in the three rice types of both polished and brown rice were within the only published regulatory limit of 200 ng/g.     

Determination of total arsenic content and arsenic speciation in different types of rice

Food Science and Biotechnology - The objectives of this study was to examine the amount of total arsenic and arsenic speciation in different types of rice from two areas in Korea using inductively...     

Effect of two different rice dehusking procedures on total arsenic concentration in rice

Pollution of subterranean water by arsenic (As) in Asia has resulted in the worst chemical disaster in human history. For populations living on subsistence rice diets, As contamination of rice grain contributes greatly to dietary As exposure. The main objectives of this study were to compare two dehusking processes: (a) wet process (soaking of rice, boiling and mechanical hulling) and (b) dry process (mechanical hulling), and recommend the method leading to a lower As content in commercial rice. In general, hulling of paddy rice (373 μg As kg⁻¹) significantly decreased As content in rice grain (311 μg As kg⁻¹). The final As concentrations in boiled rice (final product of the wet process) and atab rice (dry process) were 332 and 290 μg kg⁻¹. Thus, the dry method is recommended for dehusking paddy rice if not As-free water is available. However, villagers can reduce the As content in the wet system by discarding the soaking water and using new water for the light boiling. Finally, it is not recommended to use rice husk for feeding animals because the As concentration is very high, approximately 1,000 μg As kg⁻¹.     

原子荧光光谱法测定糙米粉中总砷及无机砷的含量

目的 建立原子荧光光谱法测定糙米粉中总砷及无机砷含量的分析方法。方法 糙米粉经烘干称取后, 用硝酸高氯酸硫酸混合湿法消解快速进行总砷前处理, 用1%硝酸水浴热提取进行无机砷前处理, 分别利用原子荧光光谱法及液相色谱-原子荧光光谱法进行总砷和无机砷的测定。结果 总砷在6.0~20.0 μg/L浓度范围内, 无机砷在10.0~100.0 μg/L浓度范围内均具有良好的线性关系(r＞0.999), 大米粉质控样测定值总砷0.26 mg/kg及无机砷0.17 mg/kg, 均在参考值允许范围内, 回收率范围为92.3%~127.1%, 均具有较高的回收率。结论 优化湿法消解处理能较高效地得到准确的测定结果, 糙米粉中无机砷经热提取及流动相环节的优化后, 也可得满意检测结果。     

Determination of arsenic species in rice grains using HPLC-ICP-MS

Determination of As species in rice is necessary because inorganic As species (arsenate (As^V) and arsenite (As^III)) are more toxic than organic As (monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)). This study evaluated the As species in Korean and USA rice grains. Levels were determined using microwave extraction and high performance liquid chromatography coupled with inductively coupled plasma-mass spectrometry (HPLC-ICPMS). Arsenite and DMA were the major species detected in Korean and USA rice. The percentage of inorganic As was 76.94% (54.50–87.86%) for Korean rice and 69.28% (52.94–72.92%) for USA samples. The order and percentage of As species observed in Korean and USA rice were As^III (70%)>DMA (24%)>As^V (5%)>MMA (1%), and As^III (64%)>DMA (28%)>As^V(5%)>MMA (3%), respectively. The As^III concentrations were not significantly different in Korean rice grains, compared to USA grains. The high As^III predominance indicates an elevated toxic effect of As in rice grains and needs further attention.     

稻谷在加工过程中无机砷含量的分布情况

目的 测定糙米、大米及糠粉中无机砷的含量,研究无机砷在稻米中的分布情况.方法 随机抽取20份稻谷样本,经实验室垄谷和碾米后得到的糙米、大米及糠粉.使用液相色谱-原子荧光联用仪检测所得糙米、大米及糠粉中的无机砷含量.结果 样本中的砷主要以亚砷酸根[As(Ⅲ)]的形式存在.糙米中的亚砷酸根[As(Ⅲ)]含量为(0.122±...     

Total and speciated arsenic levels in rice from China

Although the need for policy development on arsenic (As) in rice has been recognized and a legally enforceable maximum contaminant level (MCL) for inorganic arsenic (As_i) in rice has been established in China, evidence reported in this article indicates that the risk of exposure to As for the Chinese population through rice is still underestimated. Polished rice from various production regions of China was analyzed for total As and arsenic species using HPLC–ICPMS. Total As concentration ranged 65.3–274.2 ng g^?1, with an average value of 114.4 ng g^?1. Four arsenic species, including arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA), were detected in most rice samples. The As_i (As(III) + As(V)) species was predominant, accounting for approximately 72% of the total As in rice, with a mean concentration of 82.0 ng g^?1. In assessing the risk from As in rice, we found that As intake for the Chinese population through rice is higher than from drinking water, with a 37.6% contribution to the maximum tolerable daily intake (MTDI) of As recommended by World Health Organization (WHO), compared with 1.5% from drinking water. Compared to other countries, the risk for the Chinese from exposure to As through rice is more severe due to the large rice consumption in China. Therefore, not only the scientific community but also local authorities should take this risk seriously. Furthermore, more stringent legislation of the MCL for rice should be enacted to protect the Chinese consumer from a high intake of As.     

Biotransformation and accumulation of arsenic in soil amended with seaweed

For many coastal regions of the world, it has been common practice to apply seaweed to the land as a soil improver and fertilizer. Seaweed is rich in arsenosugars and has a tissue concentration of arsenic up to 100 micro/g g(-1). These arsenic species are relatively nontoxic to humans; however, in the environment they may accumulate in the soil and decompose to more toxic arsenic species. The aim of this study was to determine the fate and biotransformation of these arsenosugars in soil using HPLC-ICP-MS analysis. Data from coastal soils currently manured with seaweeds were used to investigate if arsenic was accumulating in these soils. Long-term application of seaweed increased arsenic concentrations in these soils up to 10-fold (0.35 mg of As kg(-1) for nonagronomic peat, 4.3 mg of As kg(-1) for seaweed-amended peat). The biotransformation of arsenic was studied in microcosm experiments in which a sandy (machair) soil, traditionally manured with seaweed, was amended with Laminaria digitata and Fucus vesiculosus. In both seaweed species, the arsenic occurs in the form of arsenosugars (85%). The application of 50 g of seaweed to 1 kg of soil leads to an increase of arsenic in the soils, and the dominating species found in the soil pore water were dimethylarsinic acid (DMA(V)) and the inorganic species arsenate (As(V)) and arsenite (As(III)) after the initial appearance of arsenosugars. A proposed decomposition pathway of arsenosugars is discussed in which the arsenosugars are transformed to DMA(V) and further to inorganic arsenic without appreciable amounts of methylarsonic acid (MA(V)). Commercially available seaweed-based fertilizers contain arsenic concentration between 10 and 50 mg kg(-1). The arsenic species in these fertilizers depends on the manufacturing procedure. Some contain mainly arsenosugars while others contain mainly DMA(V) and inorganic arsenic. With the application rates suggested by the manufacturers, the application of these fertilizers is 2 orders of magnitude lower than the maximum permissible sewage sludge load for arsenic (varies from 0.025 kg ha(-1) yr(-1) in Styria, Austria, to 0.7 kg ha(-1) yr(-1) in the U.K.), while a direct seaweed application would exceed the maximum arsenic load by at least a factor of 2.     

Increase in rice grain arsenic for regions of Bangladesh irrigating paddies with elevated arsenic in groundwaters

Concern has been raised by Bangladeshi and international scientists about elevated levels of arsenic in Bengali food, particularly in rice grain. This is the first inclusive food market-basket survey from Bangladesh, which addresses the speciation and concentration of arsenic in rice, vegetables, pulses, and spices. Three hundred thirty aman and boro rice, 94 vegetables, and 50 pulse and spice samples were analyzed for total arsenic, using inductivity coupled plasma mass spectrometry (ICP-MS). The districts with the highest mean arsenic rice grain levels were all from southwestern Bangladesh: Faridpur (boro) 0.51 > Satkhira (boro) 0.38 > Satkhira (aman) 0.36 > Chuadanga (boro) 0.32 > Meherpur (boro) 0.29 microg As g(-1). The vast majority of food ingested arsenic in Bangladesh diets was found to be inorganic; with the predominant species detected in Bangladesh rice being arsenite (AsIII) or arsenate (AsV) with dimethyl arsinic acid (DMAV) being a minor component. Vegetables, pulses, and spices are less important to total arsenic intake than water and rice. Predicted inorganic arsenic intake from rice is modeled with the equivalent intake from drinking water for a typical Bangladesh diet. Daily consumption of rice with a total arsenic level of 0.08 microg As g(-1) would be equivalent to a drinking water arsenic level of 10 microg L(-1).     

Arsenic in rice: I. Estimating normal levels of total arsenic in rice grain

High levels of arsenic (As) in rice grain are a potential concern for human health. Variability in total As in rice was evaluated using 204 commercial rice samples purchased mostly in retail stores in upstate New York and supplemented with samples from Canada, France, Venezuela, and other countries. Total As concentration in rice varied from 0.005 to 0.710 mg kg(-1). We combined our data set with literature values to derive a global "normal" range of 0.08-0.20 mg kg(-1) for As concentration in rice. The mean As concentrations for rice from the U.S. and Europe (both 0.198 mg kg(-1)) were statistically similar and significantly higher than rice from Asia (0.07 mg kg(-1)). Using two large data sets from Bangladesh, we showed that As contaminated irrigation water, but not soil, led to increased grain As concentration. Wide variability found in U.S. rice grain was primarily influenced by region of growth rather than commercial type, with rice grown in Texas and Arkansas having significantly higher mean As concentrations than that from California (0.258 and 0.190 versus 0.133 mg kg(-1)). Rice from one Texas distributor was especially high, with 75% of the samples above the global "normal" range, suggesting production in an As contaminated environment.     

Comparison of a chemical and enzymatic extraction of arsenic from rice and an assessment of the arsenic absorption from contaminated water by cooked rice

Rice is a target food for arsenic speciation based analyses because of its relatively high arsenic concentration and per capita consumption rates. Improved speciation data for rice can be helpful in estimating inorganic arsenic exposures in the U.S. and in endemic populations. The inorganic arsenic exposure for cooked rice should include both the arsenic in raw rice plus the arsenic absorbed from the water used to prepare it. The amount of arsenic absorbed from water by rice during preparation was assessed using five different types of rice cooked in both contaminated drinking water and arsenic-free reagent water. The rice samples were extracted using trifluoroacetic acid (TFA) and speciated using IC-ICP-MS. The TFA procedure was able to extract 84-104% of the arsenic (As) from the five different cooked rice samples. Chromatographic recoveries ranged from 99% to 116%. The dimethylarsinic acid (DMA) and inorganic arsenic concentration ranged from 22 to 270 ng of As/g of rice and from 31 to 108 ng of As/g of rice, respectively, for samples cooked in reagent water. The overall recoveries, which relate the sum of the chromatographic species back to the total digested concentration, ranged from 89% to 117%. The absorption of arsenic by rice from the total volume of water [1:1 to 4:1 (water:rice)] used in cooking was between 89% and 105% for two different contaminated drinking water samples. A comparison of the TFA extraction to an enzymatic extraction was made using the five rice samples and NIST 1568a rice flour. The two extraction procedures produced good agreement for inorganic arsenic, DMA, and the overall recovery. Through the use of IC-ESI-MS/ MS with a parent ion of m/z 153 and fragment ions of m/z 138, 123, and 105, the structure dimethylthioarsinic acid was tentatively identified in two of the rice samples using the enzymatic extraction.     

糙米中砷形态检测方法的对比研究

目的比较液相色谱-原子荧光光谱法(highperformance liquid chromatography atomic fluorescence spectrometry,HPLC-AFS)和液相色谱-电感耦合等离子体质谱法(high performance liquid chromatography inductively coupled plasma mass spectrometry, HPLC-ICP-MS)两种方法对糙米中砷形态的测定。方法糙米样品经0.15 mol/L硝酸溶液提取,分别采用HPLC-AFS联用仪,流动相为15 mmol/L的磷酸二氢氨缓冲溶液(pH=6.0),经CNWSep AX阴离子交换色谱柱分离检测;同时,采用HPLC-ICP-MS联用仪,流动相为含5 mmol/L己烷磺酸钠、20 mmol/L柠檬酸的缓冲溶液(pH=4.3),经安捷伦ZorbaxSB-Aq反相色谱柱分离检测。结果两种方法检测4种砷形态在5.0～100.0 ng/mL范围内线性良好,相关系数均在0.999以上; HPLC-AFS法的检出限分别为2.3、0.6、1.0和1.1 ng/mL,加标回收率在85.1%～106%之间,相对标准偏差(relative standard deviation, RSD)均小于5%; HPLC-ICP-MS法的检出限分别为0.1、0.1、0.1和0.2 ng/mL,加标回收率在82.8%～106%之间,相对标准偏差(RSD)均小于5%。结论两种方法都可以满足糙米中4种砷形态的检测,在实际情况中可根据需要选择相应的检测方法。     

Speciation and localization of arsenic in white and brown rice grains

Synchrotron-based X-ray fluorescence (S-XRF) was utilized to locate arsenic (As) in polished (white) and unpolished (brown) rice grains from the United States, China, and Bangladesh. In white rice As was generally dispersed throughout the grain, the bulk of which constitutes the endosperm. In brown rice As was found to be preferentially localized at the surface, in the region corresponding to the pericarp and aleurone layer. Copper, iron, manganese, and zinc localization followed that of arsenic in brown rice, while the location for cadmium and nickel was distinctly different, showing relatively even distribution throughout the endosperm. The localization of As in the outer grain of brown rice was confirmed by laser ablation ICP-MS. Arsenic speciation of all grains using spatially resolved X-ray absorption near edge structure (micro-XANES) and bulk extraction followed by anion exchange HPLC-ICP-MS revealed the presence of mainly inorganic As and dimethylarsinic acid (DMA). However, the two techniques indicated different proportions of inorganic:organic As species. A wider survey of whole grain speciation of white (n=39) and brown (n=45) rice samples from numerous sources (field collected, supermarket survey, and pot trials) showed that brown rice had a higher proportion of inorganic arsenic present than white rice. Furthermore, the percentage of DMA present in the grain increased along with total grain arsenic.     

大米中无机砷风险评估方法学研究

目的研究风险评估在大米中无机砷健康风险防控的应用。方法以评估中国东南沿海A县县域大米中的无机砷及其干预或控制措施对当地人群的致癌风险的影响为例,将大米中无机砷的检测数据、消费量调查数据、生物利用率和剂量-反应关系模型相结合,使用@RISK 7.5对不同情景下样品来源地一般人群的膀胱癌和肺癌风险进行概率评估。结果国标限量和正常消费情景下大米来源的无机砷暴露导致的25年后膀胱癌和肺癌年新发病例数约为0.045例/10万人,在25年后一切原因导致的年新发病例数(约209.2例/10万人)中几乎可以忽略不计(约占0.021 5%),由此造成的平均预期寿命损失约为0.000 529岁/0.193 1 d。改变国标限量和/或消费结构的再干预或控制措施对风险的影响很小,即使假设无机砷限量和大米消费量均降为原来的1/2,肺癌的发病率也仅下降2.16%。结论研究显示改变消费结构和/或国标限量对降低大米中无机砷的风险意义不大,当前的假设情景也存在较大的局限性和不确定性,但本研究为整合、评价和应用新的公共卫生科学信息提供了一个方法框架。     

不同水稻品种抗镉富集能力研究

采用田间实验,选取3块稻田种植创优华占、Y两优957、Y两优911、旺两优958、旺两优950等5个水稻品种,通过对土壤pH值、土壤和稻谷重金属Cd含量的测定,分析不同品种水稻重金属Cd吸收积累特性。结果表明:土壤在实验水稻种植期间pH值和重金属Cd含量未发生变化;水稻在三个稻田种植实验组中重金属Cd含量差异较大,Y两优911品种重金属Cd含量最低(0.101～0.228mg/kg);对不同品种稻谷重金属Cd含量进行3个聚类分析,第Ⅲ类的Y两优911和创优华占稻谷重金属Cd含量最低;在不同品种稻谷重金属Cd富集能力分析中,Y两优911重金属Cd富集能力低于其他品种(P0.01)。综上所述,水稻Y两优911品种重金属Cd吸收积累相对吸收较小,可以在中、低重金属污染农田中安全种植。     

粳稻谷中镉和无机砷分布探讨

通过对糙米和大米中镉和无机砷含量的分析,发现镉在粳稻谷中分布较均匀,其含量在糙米和大米中基本一致;而无机砷在粳稻谷中主要分布在表皮,糙米通过精加工碾磨成大米后,其无机砷含量约降低了2倍。为去除粮食中重金属残留,实现粮食资源的合理化应用提供依据。