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Cyanuric acid is a suspected gastrointestinal or liver toxicant in humans. Therefore, determination of trace cyanuric acid is very important, in this work a novel, sensitive, and reliable method was developed using differential pulse polarography. Optimum conditions for analytical determination were found to be at a pH of 9.5, Britton–Robinson at a reduction potential of ?105 mV. Experimental results indicate an excellent linear correlation between the peak current and the concentration in the range of cyanuric acid from 0.5 to 27.0 µM (0.06–3.5 µg mL?1) with a correlation coefficient of 0.997. The limit of detection and limit of quantification were obtained as 0.15 and 0.5 µM (0.02–0.06 µg mL?1), respectively. The proposed method was successfully applied to the determination of cyanuric acid in pool water and in spiked milk. Cyanuric acid level in swimming pool water was found as 2.54 ± 0.47 µg mL?1 (19.7 ± 2.29 µM) in swimming pool water for N = 4 and 95% confidence interval. The recoveries were found to be sufficient. Also, the standard deviation of the data was low which shows high accuracy and precision of proposed differential pulse polarographic method. The influences of some other commonly found inorganic salts on the determination of cyanuric acid were also examined. Some interfering species were eliminated using complexing agents, e.g., EDTA. 相似文献
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Gianfranco Brambilla Stefania Paola De Filippis Vittorio Esposito Gaetano Settimo 《洁净——土壤、空气、水》2013,41(2):113-118
Dioxin‐like compounds from regular, occasional or fugitive airborne sources of emission may fall out on fodders close to be harvested for silage and hay production. In this way, a prolonged long‐term intake of contaminated forages in dairy animals may be envisaged, able to determine a rise of the background contamination in milk. We simulated different risk scenarios taking into account the inventoried bulk dry depositions in rural areas of the aforesaid contaminants, silage and hay biomass production per hectare, forages regimen in dairy animals, and the congeners carry‐over rate (COR) from forages to milk. Considering atmospheric depositions >10 pg I‐TE m?2 day?1 and accounting for a 30% COR, dairy milk could rise up to the PCDD/F level of 3 pg WHO1998‐TE g?1 fat. The modelling indicates that in rural areas bulk emissions should be selectively minimised, accounting for the calendar of the different agricultural practices, because of their potential impact on the fodders. Since environmental factors play a non‐negligible role in food production, a stronger harmonisation between I‐TE and WHO1998–2005‐TE scales with respect to dioxin‐like polychlorobiphenyl congeners inclusion is envisaged. This will allow the prevention of the human indirect exposure to such contaminants when released in the air. 相似文献
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Ren Verburg Elke Stehfest Geert Woltjer Bas Eickhout 《Global Environmental Change》2009,19(4):434-446
This study explores the effects of agricultural trade liberalisation and concomitant changes in agricultural areas and livestock production on greenhouse gas emissions using the coupled LEITAP–IMAGE modelling system. The results indicate that liberalisation leads to an increase in total greenhouse gas emissions by about 6% compared to the reference scenario value in 2015. The increase in CO2 emissions are caused by vegetation clearance due to a rapid expansion of agricultural area; mainly in South America and Southeast Asia. Increased methane emissions in the case of full liberalisation are caused by less intensive cattle farming in regions such as South America and Southeast Asia. This pattern is observed up to 2050. Total global production of milk, dairy and beef do not change with full liberalisation, but production shifts were observed from North America and Europe to South America and Southeast Asia. Results are less pronounced in variants where trade liberalisation is only implemented partially. Remarkably, our study shows in the trade barrier removal scenario larger numbers of dairy cows in Australia and New Zealand (ANZ) then with full liberalisation scenario or a variant in which only milk quota are abolished. This illustrates that different types of liberalisation need to be analysed regionally and per commodity before general conclusions on the impact of trade liberalisation can be drawn. Our study contributes new information on greenhouse gas emissions to a vast number of trade liberalisation studies that focus on economic impacts. The combined economic-environmental impacts need to be assessed in detail before general conclusions on trade liberalisation can be given. 相似文献
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The North American fossil record of dinosaur eggshells for the Cretaceous is primarily restricted to formations of the middle (Albian–Cenomanian) and uppermost (Campanian–Maastrichtian) stages, with a large gap in the record for intermediate stages. Here we describe a dinosaur eggshell assemblage from a formation that represents an intermediate and poorly fossiliferous stage of the Upper Cretaceous, the Santonian Milk River Formation of southern Alberta, Canada. The Milk River eggshell assemblage contains five eggshell taxa: Continuoolithus, Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus. These ootaxa are most similar to those reported from younger Campanian–Maastrichtian formations of the northern Western Interior than they are to ootaxa reported from older middle Cretaceous formations (i.e., predominantly Macroelongatoolithus). Characteristics of the Milk River ootaxa indicate that they are ascribable to at least one ornithopod and four small theropod species. The taxonomic affinity of the eggshell assemblage is consistent with the dinosaur fauna known based on isolated teeth and fragmentary skeletal remains from the formation, although most ornithischians and large theropods are not represented by eggshell. Relative to the Milk River Formation eggshell, similar oospecies occurring in younger Cretaceous deposits tend to be somewhat thicker, which may reflect an increase in body size of various dinosaur lineages during the Late Cretaceous. 相似文献
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研究保健食品—排铅奶粉 (L ead Excreting Milk Powder,LEMP)对实验性铅中毒大鼠的粪铅和血铅含量的影响。 1)大鼠饮服 0 .2 %乙酸铅水溶液染毒 ,共三周 ,造成轻度实验性铅中毒后 ,改饮 0 .0 2 %乙酸铅水溶液维持 ,口服 L EMP5、10、15g/ kg连续观察 10 d。结果表明 ,与对照组比较能明显增加粪铅含量 (P<0 .0 1) ,抑制血铅升高 (P<0 .0 1) ,有效地阻止大鼠对铅的吸收。 2 )大鼠饮服 0 .3%和 0 .6 %乙酸铅水溶液 ,造成重度铅中毒后 ,在脱离毒源的情况下 ,口服 L EMP10 g/kg,连续观察 15d。结果表明 ,与对照组比较 ,实验组能显著降低血铅浓度 (P<0 .0 1) ,显示出较好的体内驱铅效果。 相似文献
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The fluoride content of dung, urine and milk of grazing animals, for example cow, she-buffalo, doe and ewe, was studied in
the Podili area, India, (endemic fluorosis) and also in Tirupati (non-fluorosis) for the purpose of comparison. The data reveal
that the fluoride content of the urine of animals is suitable for the preparation of biogeochemical atlases studying the environmental
effect in relation to health.
Received: 1 August 1997 · Accepted: 2 March 1998 相似文献
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