高压微波催化合成肉桂酸甲酯

在硫酸铁铵的催化下 ,利用高压微波技术 ,快速合成了肉桂酸甲酯。最佳反应条件为 :甲醇和肉桂酸的摩尔比为 5 :1,催化剂用量为 2 .0g ,微波时间为 3min ,微波功率为 72 9W ,产率达93.8%。     

Foodborne Exposure to Pesticides and Methylmercury in the United Arab Emirates

As part of a comprehensive environmental health strategic planning project initiated by the government of Abu Dhabi, we assessed potential dietary exposure in the United Arab Emirates (UAE) to methylmercury (in seafood) and pesticides (in fruits and vegetables) above international guideline levels. We present results for the UAE population by age, gender, and body mass index. Our results show very low daily risks of exposure to pesticides in fruits and vegetables at levels exceeding WHO guidelines even under the conservative assumption that no pesticides are removed during washing and food preparation. Thus, exposure to pesticides on fruits and vegetables does not appear to be a major public health concern in the UAE. The chances of exposure to methylmercury in seafood are much higher; our model estimates a mean 1 in 5 daily risk of exceeding the FAO/WHO provisional tolerable weekly intake. However, great caution should be used in interpreting these results, as we analyzed only the risks and not the substantial benefits of fish consumption. In fact, previous studies have demonstrated that exposure to the n‐3 polyunsaturated fatty acids in fish can increase IQ in developing children, and it can substantially decrease the risk in adults of coronary heart disease and stroke. Further research is warranted to compare the risk of Me‐Hg exposure from fish to the nutritional benefits of fish consumption in the UAE and to determine appropriate methods to communicate risk and benefit information to the UAE population.     

Efficacy of Risk-Based, Culturally Sensitive Ogaa (Walleye) Consumption Advice for Anishinaabe Tribal Members in the Great Lakes Region

The Great Lakes Indian Fish and Wildlife Commission (GLIFWC) has produced Ogaa (walleye— Sander vitreus ) consumption advisories since 1996 for Anishinaabe from GLIFWC member tribes in the 1837 and 1842 ceded territories of Wisconsin. GLIFWC's advisory maps were revised in 2005 to address cultural sensitivities (to protect tribal lifeways), to utilize recent mercury exposure information, and to incorporate changes in advisory levels for methyl mercury. Lake-specific, risk-based, culturally sensitive consumption advice was provided on color-coded maps for two groups: children under age 15 years and females of childbearing age, and males 15 years and older and females beyond childbearing age. The maps were distributed to, and a behavioral intervention program developed for, the six GLIFWC member tribes in Wisconsin as well as member tribes in Minnesota and the 1842 ceded territory of Michigan. Tribal fish harvesters, tribal health care providers, women of childbearing age or with young children, tribal leaders, elders, and children were targeted specifically for the behavioral intervention. The efficacy of the behavioral intervention was assessed using surveys of 275 tribal fish harvesters from Wisconsin, 139 tribal harvesters from Michigan and Minnesota, and 156 Wisconsin women of childbearing age. Significant increases in the percentage of survey participants who indicated awareness of advisory maps occurred among Wisconsin harvesters (increase from 60% to 77%), Michigan and Minnesota harvesters (29% to 51%), and women of childbearing age in Wisconsin (40% to 87%). A significant increase in preference for smaller Ogaa occurred among tribal harvesters in Wisconsin (41% to 72%) and tribal harvesters in Michigan and Minnesota (49% to 71%), although not among women of childbearing age. The GLIFWC map-based advisory program did not adversely affect tribal harvest of Ogaa, which increased from 63,000 to 88,000 fish in the three states after the intervention.     

An Exposure Assessment of Methyl Mercury via Fish Consumption for the Japanese Population

The objective of this article was to propose an exposure assessment model to describe the relationship between fish consumption and body methyl mercury (MeHg) levels in the Japanese population. Individual MeHg intake was estimated by the summation of species-specific fish consumption multiplied by species-specific fish MeHg levels. The distribution of fish consumed by individuals and the MeHg level in each fish species were assigned based on published data from Japanese government institutions. The probability of MeHg intake for a population was accomplished through a Monte Carlo simulation by the random sampling of fish consumption and species-specific MeHg levels. Internal body MeHg levels in blood and hair were estimated using a one-compartment model. Overall, the mean value of MeHg intake for the Japanese population was estimated to be 6.76 μg/day or 0.14 μg/kg body weight per day (bw/day), while the mean value for the hair mercury level was 2.02 μg/g. Compared with the survey data that tabulated hair mercury levels in a cross-section of the Japanese population, the simulation results matched the hair mercury survey data very well for women, but somewhat underestimated for men and all of the population. This exposure assessment model is a useful attempt at further risk assessment with respect to a risk-benefit analysis.     

Combining Food Frequency and Survey Data to Quantify Long-Term Dietary Exposure: A Methyl Mercury Case Study

Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of "usual" intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES.     

秸杆资源化利用及对染料废水的处理

采用紫外-可见分光光度法,研究经无水乙醇提取后的农业稻草提取剂溶液对甲基紫的吸附作用,探讨在不同pH值、初始浓度和吸附时间条件下,不同用量的吸附剂对甲基紫溶液的吸附效果。结果表明,当pH为10.34时,400 mg的稻草吸附剂对48.29 mg/L,15mL的甲基紫吸附30 min去除率达72.1%。     

甲基叔丁基醚-甲醇二元体系汽液相平衡的研究

用静态法实测了甲基叔丁基醚 -甲醇二元体在 0 .4— 0 .8MPa下的汽液相平衡数据 ,并进行了恒压下热力学一致性检验 .用 NRTL和 Wilson方程关联了有关数据 ,结果表明实验数据可靠 ,NRTL模型拟合精度较好     

氯乙酸甲酯的合成

本文采用氯乙酸和甲醇酯化反应合成氯乙酸甲酯,讨论了原料摩尔比、反应温度、反应时间和催化剂用量对产率、产品质量的影响。最佳工艺条件为反应温度90℃以上,反应时间3小时,原料摩尔比氯乙酸:甲醇为1:1.2～1.5,催化剂用量为氯乙酸用量的3％,产率可达到65.2％。采用动态法合成氯乙酸甲酯,产率可进一步达到72.3％,产品质量合格。     

水中碱度组成的分析

本文从理论和实践的结合上概述了工农业生产和科学研究中,水中常见的几种碱度的组成、分类和分析方法,并对水中几种碱度的组成与测定结果的关系进行了综合分析。     

甲基紫-溴酸钾褪色光度法测定微量甲醛

在稀硫酸溶液中,甲醛对溴酸钾氧化甲基紫褪色反应有催化作用,研究了其动力学条件,建立了新的测定痕量甲醛的褪色光度分析方法,线性范围为0.2～5.0μg/mL.该法用于啤酒、饮料及漆料中微量甲醛的测定,标准加入回收率为95.6～104.8%,RSD为1.8～4.4%.