Health impact assessment of arsenic and cadmium intake via rice consumption in Bangkok,Thailand

Consumption of contaminated food is a major route of exposure to toxic contaminants for humans. To protect against potential negative health effects from rice consumption, As and Cd concentrations in rice sold in Bangkok were determined, and non-carcinogenic and carcinogenic risk assessments were conducted. Four types of rice (n = 97), namely, white jasmine, white, glutinous, and brown jasmine, were collected. Samples were acid-digested and analyzed for total concentrations of As and Cd by ICP-MS. The average concentrations of As and Cd were 0.205 ± 0.008 and 0.019 ± 0.001 mg kg^?1, respectively. Approximately 22.8, 62.5, and 57.1% of white, white jasmine, and brown jasmine rice, respectively, contained As concentrations exceeding the Codex inorganic As standards for polished and unpolished rice. Brown jasmine rice contained significantly higher As concentrations than the other types of rice. However, Cd concentrations in all rice samples were significantly lower than the Codex standard of 0.4 mg kg^?1. Children are exposed to the highest amounts of both elements. Concerning As exposure through the consumption of different types of rice in the same age group, the consumption of brown jasmine rice caused approximately 1.7 to 2.3 times higher As exposure rates compared to the consumption of other types of rice. Non-carcinogenic risks (hazard quotient (HQ)) of As exposure from all types of rice were higher than the threshold limit of 1. HQ in children ranging from 2.1 to 4.9 was significantly higher than HQ in the other age groups. The cancer risks from As exposure were negligible in all groups.     

基于高光谱分形分析的水稻镉污染动态监测

水稻中过量镉会影响叶绿素含量和细胞结构,进而改变水稻在光谱维上的特征表现.利用长春郊区实测大田水稻高光谱数据和同步测量的土壤、水稻生化参数,系统分析水稻冠层光谱曲线的分形特征及不同镉污染胁迫程度下光谱分维与两类光谱指数的变化情况,构建光谱分维、光谱指数与水稻叶片镉浓度的空间分布图,探讨光谱分维与光谱指数在提取镉污染胁迫等级信息中的相互关系及物理机制.研究表明,光谱分维相对于光谱指数能够更好地综合反映镉污染胁迫下水稻生理特征参数的变化,因而为有效地大范围动态监测水稻镉污染提供诊断依据.     

水稻重金属含量与土壤质量的关系

根据“淮安市绿色食品基地调查以及相关研究”课题资料 ,分析了水稻中重金属含量与其土壤质量的关系。结果表明 ,重金属含量在水稻中的分布是 :根 >茎叶 >籽粒 ;水稻籽粒对重金属的吸收特点因其元素不同而差异较大 ,重金属元素被水稻糙米吸收的程度为 :砷 <镉 <汞 <铅 <锰 <铬 <铜 <锌 ;在糙米中检出的重金属铜和铬的含量与土壤中铜和铬的含量呈显著性相关关系 ,铅、锌、锰的含量与土壤中铅、锌、锰的含量相关关系不显著     

Determination and study on dissipation and residue determination of cyhalofop-butyl and its metabolite using HPLC-MS/MS in a rice ecosystem

Cyhalofop-butyl is an aryloxyphenoxypropionate postemergence herbicide with good control of barnyard grass in rice paddies. In this study, method for the determination of cyhalofop-butyl and its metabolite was developed with high-performance liquid chromatography tandem mass spectrometry. Dissipation and residue levels of cyhalofop-butyl and its metabolite in rice ecosystems were also investigated. Recoveries and relative standard deviations of cyhalofop-butyl and cyhalofop acid in six matrices at three spiking levels ranged from 76.1 to 107.5 % and 1.1 to 8.2 %, respectively. The limit of quantitation (LOQ) of cyhalofop-butyl and cyhalofop acid was 0.01 mg/kg in paddy water, paddy soil, rice plant, rice straw, rice hulls, and husked rice. For field experiments, the results showed that cyhalofop-butyl degraded to cyhalofop acid quickly, and the half-lives of cyhalofop acid in paddy water, paddy soil, and rice plant were 1.01–1.53, 0.88–0.97, and 2.09–2.42 days, respectively. Ultimate residues of cyhalofop-butyl and its metabolite in the rice samples were not detectable or below 0.01 mg/kg at harvest.     

Characterization of ambient air quality during a rice straw burning episode

Spatiotemporal characteristics and impact of ambient air-quality attributed to open burning of rice straw were analyzed and estimated with measured data. Two multivariate analytic methods, factor analysis and cluster analysis, were adopted to analyze the temporal and spatial impact on ambient air-quality during the rice straw burning episode. Temporal features of three scenarios were cited to compare the concentrations for ambient air-quality between the rice straw burning episode and non-episodes over two typical stations by factor analysis. Factor analysis demonstrated that the first rotational component, identified as being highly correlated to the open burning of rice straw, accounts for about 40% of the concentration variance for ambient air-quality. In typical air-quality stations, the average hourly incremental concentrations between the episode and non-episodes were greater than 300 μg m(-3) for PM(10), 1.0 ppm for CO and 35 ppb for NO(2) during the impact of rice straw burning. Factor analysis presented that the first rotated component was highly correlated with several primary pollutants (NO(2), NMHC, PM(10) and CO) during the rice straw burning episode, while every component was only highly correlated with a unique air pollutant during non-episodes. The delineation isopleths indicated that factor analysis could serve as a better method than cluster analysis and provides cross-county cooperation for local governments located in the same separated district during the rice straw burning season. The results of factor analysis revealed that CO is the best index to demonstrate the impact of rice straw burning than the other six air pollutants measured during the episode. Backward trajectory analysis supplied a cause-effect relationship between measured stations and specific rice planted regions during the rice straw burning episode.     

Airborne rice pollen and pollen allergen in an agricultural field: aerobiological and immunochemical evidence

Grass pollens are well known among the health hazardous bioaerosols causing respiratory allergy. Being an important member of the grass family, the rice plants contribute a huge pollen load in agricultural fields during flowering. This results in a seasonal trigger of hay fever and respiratory allergy in the field workers and people living in the vicinity. Studies on the monitoring of airborne rice pollen and the intensity of the released allergen in agricultural fields are largely lacking. The aims of the present study were: (1) daily and hourly monitoring of airborne rice pollen in an agricultural field during the flowering period of plants in a winter crop season by using the Burkard 7-Day Volumetric Sampler and (2) the measurement of hourly airborne allergen intensity in the field in a peak rice pollen period by the double-antibody and chemiluminescence techniques to find out its relationship with the airborne rice pollen concentration. The monthly average concentration of rice pollen was 95 pollen m(-3) and the range of daily average pollen concentration was 0 to 386 pollen m(-3). A bimodal diurnal periodicity showed that the airborne rice pollen concentrations remained high at two different times of the day: between 08:00 h to 12:00 h and 14:00 h to 16:00 h. Deposition of airborne rice pollen allergen showed darker intensities on the immunostained tapes from the Burkard Sampler at the same two positions corresponding to higher pollen counts. These observations provided direct evidence of the allergenicity of airborne rice pollen in field conditions.     

Long-term effect of rice-based farming systems on soil health

Integrated rice–fish culture, an age-old farming system, is a technology which could produce rice and fish sustainably at a time by optimizing scarce resource use through complementary use of land and water. An understanding of microbial processes is important for the management of farming systems as soil microbes are the living part of soil organic matter and play critical roles in soil C and N cycling and ecosystem functioning of farming system. Rice-based integrated farming system model for small and marginal farmers was established in 2001 at Central Rice Research Institute, Cuttack, Odisha. The different enterprises of farming system were rice–fish, fish–fingerlings, fruits, vegetables, rice–fish refuge, and agroforestry. This study was conducted with the objective to assess the soil physicochemical properties, microbial population, carbon and nitrogen fractions, soil enzymatic activity, and productivity of different enterprises. The effect of enterprises induced significant changes in the chemical composition and organic matter which in turn influenced the activities of enzymes (urease, acid, and alkaline phosphatase) involved in the C, N, and P cycles. The different enterprises of long-term rice-based farming system caused significant variations in nutrient content of soil, which was higher in rice–fish refuge followed by rice–fish enterprise. Highest microbial populations and enzymatic properties were recorded in rice–fish refuge system because of waterlogging and reduced condition prolonged in this system leading to less decomposition of organic matter. The maximum alkaline phosphatase, urease, and FDA were observed in rice–fish enterprise. However, highest acid phosphatase and dehydrogenase activity were obtained in vegetable enterprise and fish–fingerlings enterprise, respectively.     

Dissipation and residues of bispyribac-sodium in rice and environment

The dissipation and residues of bispyribac-sodium in rice cropping system were studied. Bispyribac-sodium residues were extracted by a simple analytical method based on QuEChERs and detected by LC-MS/MS. The limit of detection for bispyribac-sodium of this method was 0.375?×?10^?3 ng. The limit of quantification (LOQ) was 5.0 μg/kg for rice plant samples, 2.0 μg/kg for rice hull, 0.2 μg/kg for water, and 0.1 μg/kg for soil and husked rice samples. The average recoveries of bispyribac-sodium ranged from 74.7 to 108 %, with relative standard deviations less than 13 %. The half-lives of bispyribac-sodium in rice plant, water, and soil were in the range of 1.4–5.6 days. More than 90 % of bispyribac-sodium residue dissipated within 5 days. The final residues of bispyribac-sodium in rice were all below LOQ at harvest time.     

钝化材料对Cd污染农田修复及其后效探究

在田间试验条件下,考察不同钝化材料对农田Cd轻度污染水稻修复效果及稻麦轮作后第二年水稻修复后效。结果表明,在轻度Cd污染农田中,各钝化材料处理均能不同程度降低土壤有效态Cd含量和水稻籽粒中Cd含量。其中,在钝化材料施用当季和稻麦轮作后第二季水稻中修复效果最好的处理为中量纳米材料处理和石灰配施中量纳米材料处理,这两种处理对土壤有效态Cd含量降低率分别为50.94%和47.15%,对水稻籽粒中Cd含量降低率分别为73.74%和69.41%。     

无污染农产品对土壤铅环境质量标准要求的变化——个案研究

研究了江苏南通某乡镇土壤铅的污染以及水稻对土壤铅的吸收。结果表明,研究区土壤与稻米铅污染严重。通过盆栽实验建立了水稻对铅的吸收积累及评估模型,提出了符合该地区大米安全生产的土壤铅临界含量值,为土壤铅环境质量标准的研究提供了参考实例。同时结合国内外环境质量标准的对比,提出无污染农产品对土壤铅环境质量标准要求的变化,建议制/修订土壤铅环境质量标准值。土壤环境二级标准值由现行的250～350mg/kg改为80mg/kg。     

Toxicity evaluation of natural samples from the vicinity of rice fields using two trophic levels

An ecotoxicological screening of environmental samples collected in the vicinity of rice fields followed a combination of physical and chemical measurements and chronic bioassays with two freshwater trophic levels (microalgae: Pseudokirchneriella subcapitata and Chlorella vulgaris; daphnids: Daphnia longispina and Daphnia magna). As so, water and sediment/soil elutriate samples were obtained from three sites: (1) in a canal reach crossing a protected wetland upstream, (2) in a canal reach surrounded by rice fields and (3) in a rice paddy. The sampling was performed before and during the rice culture. During the rice cropping, the whole system quality decreased comparatively to the situation before that period (e.g. nutrient overload, the presence of pesticides in elutriates from sites L2 and L3). This was reinforced by a significant inhibition of both microalgae growth, especially under elutriates. Contrary, the life-history traits of daphnids were significantly stimulated with increasing concentrations of water and elutriates, for both sampling periods.     

Assessment of pesticide residues in freshwater areas affected by rice paddy effluents in Southern Japan

Pesticide residues in five freshwater areas that are directly affected by rice paddy effluents in southern Japan were measured to determine their maximum concentrations and temporal variations. Water samples were collected every week during the 2005 rice planting season in Kagoshima Prefecture and stations were established in Amori River, Sudo River, Nagaida River (that drains into the bigger Kotsuki River), rice paddy drainage canal, and wastewater reservoir (that collects effluents from rice paddy fields). Of the 14 target pesticides examined, a total of 11 were detected in all stations. Mefenacet, fenobucarb, and flutolanil were the three pesticides with the highest maximum concentrations and were also detected frequently. Analysis of temporal variations of pesticides showed that herbicides had relatively higher concentrations in the earlier stages of the rice planting season, while insecticides and fungicides had relatively higher concentrations at the later stages. There was no significant difference among stations with regards to the temporal patterns of the top three pesticides. The calculated toxic units were less than 1 in all stations, implying low or negligible environmental risk of pesticides detected to freshwater organisms.     

江苏省典型农田耕作层土壤——谷物籽粒中镉的迁移转化特征

于2013年—2014年通过野外调查和盆栽试验的方法,采集江苏省境内典型农田耕作层(0~20 cm)土壤及其对应点位的水稻/小麦籽粒,分析其中的ω(Cd)(全量、0.01 mol/L CaCl_2提取态含量和0.05 mol/L CaCl_2提取态含量),及Cd在土壤—谷物籽粒系统中的迁移转化特征。结果表明,水稻籽粒(糙米)中ω(Cd)与土壤p H值呈负相关,与0.01 mol/L CaCl_2提取态含量呈正相关,且相关性在0.01水平下显著,而糙米中ω(Cd)与土壤中Cd总量以及土壤中的ω(有机质)的相关性较弱;麦粉ω(Cd)与0.01 mol/L CaCl_2提取态含量、土壤中总ω(Cd)和土壤ω(有机质)呈显著正相关,而面粉中ω(Cd)与土壤p H值的相关性较弱,说明淹水可以有效降低水稻对Cd的吸收。     

Methane emissions from ricefields as affected by organic amendment, water regime, crop establishment, and rice cultivar

Methane fluxes from Beijing ricefields as affected by organic amendment, water regime, crop establishment method, and rice cultivar were measured with a closed chamber method in 1990, 1991, 1995, and 1996. Total fluxes from plots receiving high organic amendment always exceeded those from the low-input plots. Compared with continuous flooding, intermittent irrigation (there were a few days of no standing water between two irrigations) and constant moisture (the field had no standing water, but remained saturated) reduced methane emission rate by 25.4 and 58.4%, respectively. Methane flux from a dry-seeded rice field was 75.2% lower than from a transplanted ricefield although both dry-seeded rice plots and transplanted ricefields were initially flooded at the same time. Rice cultivars differed in methane emission rates by 9.0–55.7%. Emission rates were positively correlated with aboveground dry matter production and root weight, but not grain yield. Intermittent irrigation and rice cultivar seem to be the most promising methods for mitigating methane emission from ricefields; they do not affect rice yield and are easily implemented at the farm level.     

Arsenic concentrations in local aromatic and high-yielding hybrid rice cultivars and the potential health risk: a study in an arsenic hotspot

The presence of high levels of arsenic (As) in rice fields has negative effects on the health of those consuming rice as their subsistence food. This study determined the variation in total As concentration in local aromatic rice (LAR) (kalijira) and two high-yielding varieties (HYVs) (BRRI dhan 32 and BRRI dhan 28) grown in paddy fields in Matlab, Bangladesh, an As hotspot with elevated As levels in groundwater. Mature rice grain samples and soil samples were collected from different paddy fields, and the As concentrations in both the de-husked grains and the husks of the three rice cultivars were analysed to identify the safest of the three cultivars for human consumption. The results showed that the total As concentration was higher (0.09–0.21 mg As kg^?1) in the de-husked grains of LAR than in the husks, while the opposite was found for the HYV rice. Moreover, the As concentration in soil samples was 2 to 5-fold higher for the LAR than for the HYVs, but the As accumulation factor (AF) was lower in the LAR (0.2–0.4%) than in the HYVs (0.9–1%). Thus, LAR can be considered the safest of the three cultivars for human consumption owing to its low AF value. Furthermore, due to the low AF, growing LAR instead of HYVs in soils with slightly elevated As levels could help improve the food safety level in the food chain.     

南通平原河网地区典型农田系统地下水硝态氮污染调查

针对平原河网地区典型农田系统灌溉施肥带来的地下水环境污染问题,采集南通地区蔬菜地、水稻-小麦轮作地、水稻-油菜轮作地和桑地地下水样品,分析了不同农田种植体系下的地下水污染程度。结果表明,蔬菜、桑地、水稻-油菜轮作、水稻-小麦轮作地地下水的硝态氮(N)平均值分别为12.2,9.53,7.95和6.12 mg/L,与氮肥用量呈显著的正相关关系;研究区域地下水硝态氮超Ⅲ类标准率(20 mg/L)的为4.8%,表明地下水已部分受到硝态氮污染。     

Leaching behavior of nitrogen in a long-term experiment on rice under different N management systems

The leaching behavior of nitrogen was studied in single rice paddy production ecosystems in Tsukuba, Japan after 75 years of consistent fertilization regimes (no fertilizer, ammonium sulfate, a combination of composted rice straw with soybean cake, and fresh clover). During the 75-year period, management was unchanged with respect to rice planting density, irrigation, and net N fertilization for each field to which an N-source was added. Percolation water was collected, from May 2001 to April 2002, using porous suction cups installed in the fields at depths of 15, 40, and 60 cm. All water samples were taken to the laboratory for the measurement of both NH₄ ^?+??CN and NO₃ ^????CN concentrations using a continuous-flow nitrogen analyzer. The result indicated that there were significant differences in N leaching losses between treatments during the rice growing season. Total N leaching was significantly lower with the application of composted rice straw plus soybean cake (0.58 kg N ha^???1) than with ammonium sulfate (2.41 kg N ha^???1), which resulted in N leaching at a similar level to that with the fresh clover treatment (no significant difference). The majority of this N leaching was not due to NO₃ ^????CN loss, but to that of NH₄ ^?+??CN. The mean N leaching for all fertilizer treatments during the entire rice growing season was 1.58 kg N ha^???1. Composted rice straw plus soybean cake produced leaching losses which were 65?C75% lower than those with the application of fresh clover and ammonium sulfate. N accumulation resulting from nitrification in the fallow season could be a key source of nitrate?CN leaching when fields become re-flooded before rice transplanting in the following year; particular attention should be paid to this phenomenon.     

Adsorption-desorption and leaching potential of glyphosate and aminomethylphosphonic acid in acidic Malaysian soil amended with cow dung and rice husk ash

This study investigates adsorption-desorption and the leaching potential of glyphosate and aminomethylphosphonic acid (AMPA) in control and amended—addition of cow dung or rice husk ash—acidic Malaysian soil with high oxide mineral content. The addition of cow dung or rice husk ash increased the adsorptive removal of AMPA. The isotherm data of glyphosate and AMPA best fitted the Freundlich model. The constant K_f for glyphosate was high in the control soil (544.873 mg g^?1) followed by soil with cow dung (482.451 mg g^?1) then soil with rice husk ash (418.539 mg g^?1). However, for AMPA, soil with cow dung was high (166.636 mg g^?1) followed by soil with rice husk ash (137.570 mg g^?1) then the control soil (48.446 mg g^?1). The 1/n values for both glyphosate and AMPA adsorptions were <?1 indicating their strong affinity for adsorbents. Desorption of both glyphosate and AMPA occurred only in the control soil. The compounds were not detected in soils with added cow dung or rice husk ash. The addition of cow dung or rice husk ash increased glyphosate mobility. However, ground water ubiquity scores for both control and amended soils were <?2.8. This indicated glyphosate is a transitional herbicide; therefore, its leaching potential in the soil is low, despite the addition of cow dung or rice husk ash. Addition of these wastes decreased the mobility and leaching potential of AMPA. The addition of cow dung or rice husk ash could be beneficial in increasing adsorption and enhancing degradation of these compounds.     

高效液相色谱法测定稻米和稻田水土中多菌灵残留

采用高效液相色谱法测定稻米和稻田水土中的多菌灵残留，用稀盐酸溶液提取，经液液分配净化，外标法定量。多菌灵的峰面积与进样质量在0．15ng-220ng范围内呈线性相关，在稻田水、土壤和稻米中的最低检出质量比分别为0．01mg／kg、0．01mg／kg和0．02mg／kg。3个质量水平的加标回收试验结果表明，多菌灵在稻田水样中的平均回收率为87．1％～93．0％，RSD为3．3％～3．8％；在土壤中的平均回收率为84．8％-91．9％，RSD为1．4％～4．1％；在稻米中的平均回收率为83．9％～89．6％，RSD为1．8％-5．5％。     

Mycotoxin levels and incidence of mould in Turkish rice

One hundred unpackaged rice samples, each weighing 500 g, were randomly collected at retail stores and open markets in the largest rice growing area (Thrace) in Turkey and analysed for mould counts, predominant mould genera, moisture content and mycotoxin levels. Mould counts ranged from 1.0 × 10¹ to 1.5 × 10⁴ cfu/g in 70 of 100 samples, and the correlation between moisture content and mould count was significant (p????0.05). Aspergillus spp. and Penicillium spp., potential mycotoxin producers, were the dominant moulds. In one area from which samples were collected, the mycotoxin content of rice was found to be positively correlated with moisture content; samples with higher moisture also contained higher numbers of moulds. The levels of total aflatoxins, aflatoxin B1 and ochratoxin A were higher than the maximum tolerable limits (4, 2 and 3 ??g/kg, according to the EC Regulation and the Turkish Food Codex) for 32, 14 and 30 of 100 rice samples, respectively. This is the first comprehensive report of ochratoxin A levels in rice grown in Thrace, Turkey.