Arsenic speciation in rice consumed in south-western Nigeria,and estimation of dietary intake of arsenic species through rice consumption

This study determined concentrations and speciation of arsenic (As) in rice samples obtained from the cities of Akure, Ore, Ondo and Ikare in Ondo State, south-western Nigeria. The estimated dietary intake of As from rice consumption for total As and the identified As species were compared with the As benchmark dose lower confidence limit. Analyses of rice from the four cities identified three As species: inorganic As, monomethylarsonic, acid and dimethylarsinic acid. Concentrations of total As and the As species differed significantly across the sampling locations (by a factor of 2.5 for total As). Mean levels (±S.D.) were 58.8 ± 0.7 µg/kg total As, 47.0 ± 0.6 µg/kg inorganic As, 0.33 ± 0.03 µg/kg monomethylarsonic acid, and 11.5 ± 0.1 µg/kg dimethylarsinic acid. The estimated mean dietary intakes were 4.1 µg/d total As, 3.3 µg/d inorganic As, 0.02 µg/d monomethylarsonic acid, and 0.8 µg/d dimethylarsinic acid. These values are below the benchmark dose lower confidence limit and comparable to, or lower than, those reported for other countries. Thus, consumption of rice cultivated in south-western Nigeria does not appear to have inherent As-associated health risks.     

Fluoride content of Ethiopian khat (Catha edulis Forsk) chewing leaves

The levels of water soluble and total fluoride concentration in 11 different varieties of Ethiopian khat (Catha edulis Forsk, an evergreen stimulant plant) commonly consumed in the country and exported to the neighboring countries were determined by fluoride ion-selective electrode. Known amounts of fresh khat samples were suspended in deionized water, stirred, and the supernatants exposed to a chelator that decomplexes fluoride were assayed. The total fluoride concentration in the leaves was also analyzed after the leaves were dried, charred, and ashed. Water soluble and total fluoride concentration in khat varieties varied, ranging from 0.19 to 0.43 µg g^?1 fresh weight and 3.4 to 7.1 µg g^?1 dry weight, respectively. The fluoride concentration in matured leaves (12 µg g^?1) was higher than that in young leaves (6.5 µg g^?1) dry weight. Assuming that daily khat leaves chewing for an adult is 100 g, fluoride intake from chewing leaves of the analyzed khat varieties is far below the daily fluoride tolerable upper limit. The safe intake of fluoride is recommended to be 1.5–4.0 mg day^?1 for adults and less for children. However, chewing khat leaves may contribute a significant amount of fluoride for the total daily intake of an individual and should not be overlooked while estimating the total dietary intake of fluoride for individuals chewing khat leaves regularly.     

Exploring co-investments in sustainable land management in the Central Rift Valley of Ethiopia

In Ethiopia, not only farmers but also the public and private sector partners are still hesitant to invest in sustainable land management (SLM). This study focuses on the Central Rift Valley and explores the potential for co-investments in SLM, where public and private sector partners support farmers with material, capital, knowledge, etc. A survey revealed current bottlenecks for co-investments and requirements needed to collaboratively invest in SLM. It covered 165 public sector partners (micro-, meso- and macro-level institutions) and 42 private sector partners (banks, exporters and local traders). Results for the public sector show a gap between macro- and micro-/meso-level actors concerning co-investments in SLM. Macro-level institutions do not acknowledge the bottlenecks identified by micro- and meso-level institutions (e.g. lack of accountability, top-down approaches and lack of good leadership). Similarly, opinions on requirements for co-investments in SLM differ considerably, showing that bridging the institutional micro–macro gap is crucial to co-investments. Most factors are related to the wider governance context and to different perceptions among micro- and macro-level actors as to the critical pre-conditions to co-investment in SLM. Improving governance at all institutional levels, capacity building and enhancing a common understanding on barriers to SLM is required. Results for the private sector reveal that economic bottlenecks limit possibilities to co-invest in SLM, and that enabling policies in the public sphere are required to trigger private investments. Hence, the potential for co-investments in SLM is available in Ethiopia at micro- and meso-level and within the private sector, but profound commitment and fundamental policy changes at the macro-level are required to exploit this potential.     

典型汞污染地区食物汞含量及人体汞暴露健康风险

系统采集典型汞污染地区(铅锌冶炼、金矿冶炼和燃煤电厂)食物样品(大米、蔬菜和鱼肉) 409个,测定其总汞含量以评估当地居民食物摄入汞暴露的健康风险。结果显示:铅锌冶炼地区大米总汞含量的几何均值为5.99μg·kg~(-1)(3.02～30.7μg·kg~(-1)),仅有1个样品总汞含量超过我国大米汞限量标准(20μg·kg~(-1)),蔬菜和鱼肉总汞含量分别为0.646～5.44μg·kg~(-1)和1.80～26.4μg·kg~(-1),均未超过我国食品汞限量标准;金矿冶炼地区大米总汞含量的几何均值为4.46μg·kg~(-1)(3.13～8.67μg·kg~(-1)),蔬菜和鱼肉总汞含量分别为0.760～7.83μg·kg~(-1)和1.59～21.9μg·kg~(-1),所有食物均未超过我国食品汞限量标准;燃煤电厂地区大米总汞含量的几何均值为3.63μg·kg~(-1)(1.05～11.4μg·kg~(-1)),蔬菜和鱼肉总汞含量分别为1.12～3.78μg·kg~(-1)和2.24～12.3μg·kg~(-1),所有食物均未超过我国食品汞限量标准。铅锌冶炼、金矿冶炼和燃煤电厂3个地区居民通过食用食物(大米、鱼肉和蔬菜途径)总汞摄入量的均值分别为0.068、0.038和0.031μg·d~(-1)·kg~(-1),均未超出联合国粮农组织和世界卫生组织食品添加剂联合专家委员会(JECFA)推荐的人体安全总汞摄入量0.71μg·d~(-1)·kg~(-1);表明3个研究地区居民汞暴露的风险较低。大米汞摄入量占3个地区居民食物总汞摄入量的比例分别为77.2%、70.8%和71.4%,食用大米是当地居民汞暴露的主要途径。     

源于大气的氟在水稻不同器官的分布及对糙米含氟量的影响

用开顶式熏气罩熏气的方法,研究了气源氟在水稻不同器官的分布及对糙米含氟量的影响。结果表明:气源氟主要分布于水稻叶片中,根含氟量不受气源氟的影响;籽粒含氟量取决于籽粒器官形成后空气氟浓度,与籽粒器官形成前的空气氟浓度无关;糙米氟含量与水稻抽穗齐穗后所暴露的氟剂量间呈极显著线性相关关系。     

Determination of fluoride and its effects on flavonoids in some legumes

The effects of fluoride (Fl) emission, from an aluminum (Al) reduction plant in Iran, on the concentration of Fl in six legume species were studied. In addition, the influence of Fl on leaf flavonoids was investigated. Determination of Fl in collected plants (Alhagi camelorum Fisch., Cercis siliquastrum L., Glycyrrhiza glabra L. Medicago sativa L., Robinia peseudoacacia L., and Sophora alopecuroides L.) from the factory area was performed using a Fl ion-selective electrode. Identification of flavonoids in the samples was obtained by two-dimensional paper chromatography (2-D PC) and thin layer chromatography (TLC). Controls were obtained from plants located 10 km distance from the factory. Results showed high Fl concentration in all polluted samples. Phytochemical changes in polluted leaves were observed with appearance or disappearance of some flavonoids.     

滴滴涕类农药在广东省沿海地区水产品中的残留及人体暴露水平

水产品的摄入是人体暴露于有机氯农药的主要途径之一.实验检测了采自广东省11个沿海城市水产市场的海鲜类水产品(包括6种虾类、2种蟹类和13种贝类共228个样品)中滴滴涕类农药(包括o,p’-DDT、p,p’-DDT、o,p’-DDD、p,p’-DDD、o,p’-DDE和p,p’-DDE)的残留.结果显示,DDTs在虾类、蟹类和贝类体内的平均湿重含量范围分别为0.8￣17.6ng·g-1、5.1￣16.0ng·g-1和0.6￣209.4ng·g-1.不同水产品之间因生活环境和生活习性的不同,导致其DDTs含量存在较大差别.与我国最新的食品残留标准(GB2763-2005)相比,所检测样品DDTs的含量均未超标.但若以美国环境保护局(USEPA)的标准来衡量,则DDTs含量超标的百分率达27.6%.据最近的膳食结构调查显示,广东省沿海地区的居民每天虾、蟹、贝类水产品的平均消费量为26.0g,因而通过海鲜类水产品每天摄入DDTs的量为2.4ng·kgbodyweight-1·day-1,这一结果远远低于我国设定的每日耐受摄入量(PTDI)和联合国粮农组织及世界卫生组织(FAO/WHO)的相关标准.     

Effect of biocides on the precipitation of calcium fluoride in the presence of anionic copolymeric inhibitors

The inhibitory efficiency of anionic copolymers and the effect of the biocides sodium hypochlorite, glutaraldehyde, and tris(hydroxymethyl)nitromethane on the precipitation behavior of calcium fluoride (CaF₂) were studied. The efficiency of polymeric inhibitors was traced from conductivity measurements by using half-life (t_1/2) method. X-ray diffraction parameters have been measured for calcium fluoride scale minerals. An anionic copolymer (K-798) acts as one of the best inhibitors for the precipitation process of the calcium fluoride in water as compared to K-775. It is assigned to the fact that the copolymer (K-798) contains both sulfonic acid and sulfonated styrene groups while the polymer (K-775) having only the sulfonic acid group. It was further observed that the biocides have no appreciable effect on the performance of the anionic polymeric inhibitors.     

Growth and metal accumulation response of <Emphasis Type="Italic">Vigna radiata</Emphasis> L. var PDM 54 (mung bean) grown on fly ash-amended soil: effect on dietary intake

Plants of Vigna radiata L. var. PDM 54 (mung bean) were grown in soil amended with different amounts (10 and 25%) of fly ash (FA). Although total metal content increased with increasing FA amendment, DTPA-extractable metals were higher for 10% FA. Accumulation of metals by the plants increased with increasing FA amendment and was greater in shoots than in roots (except for Mn and Cu) and seeds (except Mn). The total daily intake (TDI) of all the tested metals in seeds was within the recommended dietary allowance (RDA)/provisional tolerable daily intake (PTDI) for adults, except for Cd, which was higher than recommended values. Principal-components analysis (PCA) based on studies of physicochemical properties, DTPA-extractable metals, and metal accumulation in the different parts of V. radiata showed that physicochemical properties such as cation-exchange capacity, organic carbon, and organic matter had significant positive effects on accumulation of Cd, Co, Ni, and Pb by the plant, whereas EC had a significant negative effect. Although addition of fly ash (10%) initially increased the rate of growth, toxic symptoms were observed for 25% FA. Results from analysis of antioxidants (carotenoids, ascorbic acid, non-protein thiol, and free proline) revealed that these increased more in plants grown in 10% FA than in those grown in garden soil. Cysteine and malondialdehyde (MDA) content increased with increasing FA amendment. PCA also showed that all the antioxidants studied behaved similarly except cysteine, for which there was a close relationship with MDA content. Thus, the results obtained during this study revealed that V. radiata L. var. PDM 54 may be grown in 10% FA and/or contaminated agricultural soil.     

太湖春季水-气界面碳通量日变化观测研究

利用静态箱观测法对春季太湖不同生态类型(藻型、草型)的湖区春季水-气界面碳通量进行了昼夜连续观测,结果表明,水-气界面碳通量存在显著日变化规律,其极值均出现在凌晨5:00和下午2:00左右,但不同湖区碳通量的日变化存在明显差异。在富营养化较严重的梅梁湾湖区,昼间主要为大气CO2的汇,其平均碳通量为-7.74 mg/(m2h),夜间主要为大气CO2的源,其碳通量为5.32 mg/(m2h);湖心区域,夜间为大气CO2的源,日间在源和汇间波动。而在水质较好的东太湖区域,昼夜均为大气CO2的源,其平均碳通量为11.63 mg/(m2h)。     

Single and multiple daily dose toxicokinetics of fluoride after oral administration of sodium fluoride along with aluminum sulfate in goats

Our previous study suggested that toxicokinetic parameters of fluoride were significantly changed on the 30th day as compared with 1st day, after repeated oral administration of sodium fluoride alone for 30 days in goats. The purpose of this study was to investigate whether aluminum sulfate has ameliorative effect on the toxicokinetics of fluoride. For this, sodium fluoride (20 mg kg^?1 b. wt.) along with aluminum sulfate (150 mg kg^?1 b. wt.) was administered in goats for 30 days to investigate its effect on toxicokinetics of fluoride on days 1 and 30. The fluoride levels against time were adequately described by one compartment open model. The peak plasma level of fluoride was observed at 2 h. The toxicokinetics data revealed a nonsignificant decrease in β (elimination rate constant) and C _max (the maximum plasma concentration) and increase in t _1/2 K _a (absorption half-lives), t _1/2 β (elimination half-lives), area under the plasma (AUC) concentration versus time curve and mean residence time (MRT) was observed for the last dose from their respective first dose values. On the basis of changes in the toxicokinetic parameters, it was concluded that repeated oral administration has cumulative effect on plasma fluoride level and concurrent oral administration of aluminum sulfate has ameliorative action on the toxicokinetics of fluoride in goats.     

Temporal changes in the fluoride levels of jaws of European deer in industrial regions of Western Pomerania,Poland

The factories processing natural phosphates and apatites in Poland release into the atmosphere considerable amounts of fluorine compounds. Fluoride is known to accumulate in the hard tissues of animals and humans. This paper describes the determination of fluoride in mandibles of deer in the years 1982 and 1990. In recent years, the establishments have restricted their output and modernized the technology of phosphate fertilizer production. The fluoride content in jaws has decreased, particularly in those animals having their habitat in the vicinity of the two factories.     

Geochemistry of soil around a fluoride contaminated area in Nayagarh District,Orissa, India: Factor analytical appraisal

Fluoride contamination in soil was studied in the vicinity of a hot spring in Nayagarh district of Orissa. Both bulk soil from 0 to 30 cm depth and profile soils from 0 to 90 cm depth were analyzed for total fluoride (F_t) and 0.01 M CaCl₂ extractable fluoride (F_ca), major elements, pH, EC and Organic Carbon (OC). High concentrations of both F_t and F_ca were observed in the area surrounding the hot spring and the village of Singhpur. Principal factor analysis (PFA) on the parameters of the bulk soils suggests that two major chemical processes due to three factors, control the soil geochemistry of the area. Factor-1 contributes 37.11% of the total variance and is strongly loaded with Al, Si, Fe, F_tand F_ca, and explains the fluoride enrichment of the soil, whereas the second and the third factors contribute 16.6 and 12.2%, respectively and explain the controlling process of carbonate precipitation and soil alkalinity. Multiple regression analysis of the scores of the factors was performed to derive a fluoride contamination index in soil. The magnitude of the factor effect on the contamination index follows the order of Factor-1 > Factor-2 > Factor-3. The spatial distribution of the contamination index is used to classify the area into highly contaminated, moderately contaminated and uncontaminated zones.     

氟对中华圆田螺肝胰脏抗氧化酶和MDA的影响

选取中华圆田螺为受试动物,探究氟对其肝胰脏抗氧化酶SOD、GSH、POD活性和丙二醛MDA含量的影响。结果显示,在不同浓度水氟环境条件下(0、40、80、160 mg·L-1)连续暴露10 d、20 d和30 d时,与对照组相比,中华圆田螺肝胰脏SOD活性在暴露前20 d,中低浓度组活性被诱导升高,高浓度组受抑制降低。暴露30 d时,中低浓度组活性降低,高浓度组逐渐升高。MDA活性在暴露前20 d时,中低浓度组活性整体被诱导升高,高浓度组受抑制降低。暴露30 d时,活性受到显著抑制均低于对照组。GSH活性以诱导为主均高于对照组,POD活性在10 d时均低于对照组,而在20 d时被诱导升高且均高于对照组,30 d时中高浓度以抑制为主。上述研究结果为水质污染控制及生态风险评价提供了基础数据。     

The Impact of the Hyperacid Ijen Crater Lake. Part II: A Total Diet Study

In Asembagus (East Java, Indonesia), surface water is contaminated with effluent from the hyperacid Ijen Crater Lake. In a previous study, we reported that food crops irrigated with this water had increased concentrations of various elements. Here, we present a total diet study for adults and 6-year-old children to determine if the mean daily intake of a broad range of elements is safe and adequate. For children, the intake of B, Mg, Mn and V is high with Hazard Quotients (HQ) of 1.1 (B), 1.4 (Mn) and 1.4 (V), respectively (no TDI is available for Mg). For Mn, the daily intake is high due to the consumption of locally produced rice. Drinking water is the main source of B, Mg and V. For adults, the intake of Mg, Mn and V is also high but HQ values are ≤0.7. For both children and adults, the intake of Ca, Zn and particularly Fe is below the RNI (Fe intake is 90% below the RNI for women). It is concluded the mean intake of elements is unbalanced and Fe deficiency is probably the most serious health problem. Toxic effects cannot be fully excluded since deficiency of essential elements such as Ca, Fe and Zn can increase the absorption and retention of various elements.     

Assessing seasonal variation of fluoride in groundwater for irrigation uses through hydro-geochemical and multivariate statistical approach

Since a considerable amount of fluoride (Fl) intake also takes place through the ingestion of foods that are grown in the contaminated soil and irrigated with elemental contaminated water, this may lead to higher risk from Fl-mediated toxicity. Therefore, in the present study, a systematic delineation and characterization of Fl in agricultural tube wells in Unnao District, India, were carried out to examine seasonal variations of this element using graphical and multivariate statistical approach. The results suggested that different natural hydro-geochemical processes such as weathering of silicates, carbonates, and various ion exchange processes are the key factors responsible for the geochemistry of the groundwater in addition to the alkalinity of water. Of the water sampled, 27.3% and 18.2% were contaminated with Fl exceeding the desirable limit of 1 mg/L as prescribed by Bureau of Indian Standards during pre-monsoon and post-monsoon season. Fluoride displayed a significant positive correlation during both seasons and the water type of the majority of the samples in both seasons was bicarbonate.     

Effect of excess fluoride ingestion on human thyroid function in Gaya region,Bihar, India

Fluoride (F) is mainly ingested through drinking water and food. In addition to producing dental and skeletal fluorosis, excess fluoride may affect the functioning of many organs including the thyroid gland. The present study investigated the thyroid function of subjects with dental fluorosis from F-endemic areas of Gaya region, Bihar, India and compared it with control individuals from Bodh Gaya. The mean F concentration in groundwater of F-endemic area was 2.82 ± 0.18 mg/L (range 0.62–7.2 mg/L), while that of control area was 0.49 ± 0.04 mg/L (range 0.21–0.76 mg/L). Abnormal levels of T3, T4, and TSH were found in the study subjects from both control and F-endemic areas.     

Structural alterations in compound eye of Drosophila melanogaster in response to sodium fluoride treatment

Sodium fluoride, used as a pesticide in agriculture, is also an ingredient of toothpastes which help to fight dental problems. In this study, Drosophila melanogaster, a non-target organism, is used to explore morphological changes in the adult compound eye as a function of exposure to fluoride at 20, 40, 80, 100 and 150 mg L^?1, using scanning electron microscopy. The experimental concentrations were much lower than the ones used in the studies of the British Association of Community Dentistry. Distinct morphological alterations in the eye of the treated insects revealed ommatidial ridges and disoriented mechanosensory bristles which were most prominent in the 40 and 80 mg L^?1 treatment groups. Since humans and Drosophila share homology in many genes that are involved in developmental pathways, the present findings raise concern on the use of sodium fluoride as a pesticide.     

北京市场常见水产品中总汞、甲基汞分布特征及食用风险

以甲苯二次萃取-直接测汞的方法对北京市场常见水产品中的甲基汞进行分析测定,并评价了食用人群的暴露风险。分析样品包括大黄鱼（Pseudosciaena crocea）、虾（Penaeus chinensis）等9种常见海产品以及武昌鱼（Megalobrama amblycephala Yih）、鳙鱼（Aristichthys nobilis）2种淡水海产品。测定结果表明：海产品中总汞和甲基汞质量分数要远高于淡水鱼中的总汞和甲基汞质量分数,总汞绝大多数是以甲基汞的形式存在,所占比例从74.7%到96.0%不等;对其中3种鱼类的鱼体甲基汞分布研究表明：肌肉中的甲基汞质量分数最高,肝脏中次之,鱼鳃中质量分数最低。根据我国水产品甲基汞标准,本研究中水产品甲基汞质量分数均低于国家标准,但根据世界卫生组织（WHO）和美国环保署EPA颁布的甲基汞摄入量参考值,食用银鳕鱼等甲基汞质量分数相对较高的水产品仍然存在一定的风险,应注意限量。