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71.
Rice samples (n = 482) harvested for 2010–2012 in South Korea were analyzed for zearalenone content by high-performance liquid chromatography and fluorescence detection. The exposure of the Korean populations was assessed by a deterministic approach. Because the proportion of non-detectable results was >80% in white rice but less than <60% in brown rice, the zearalenone levels for white rice were reported as 0.52 µg kg?1 as lower bound and 2.54 µg kg?1 as upper bound, while for brown rice the middle bound value was 13.9 µg kg?1. The average dietary intake of zearalenone from white and brown rice by the Korean population was estimated to be 1.5 ng kg?1 body weight (bw) day?1 each. For heavy consumers, the average intakes were 18.5 and 10.1 ng kg?1 bw day?1, respectively. The age groups with the highest zearalenone intake were 1–2-year-old children for white rice and 3–6-year-old children for brown rice. Overall, the dietary exposure of the Korean population to zearalenone from white and brown rice was found to be lower than the provisional maximum tolerable daily intake of 0.5 μg kg?1 bw day?1.  相似文献   
72.
Moore, Johnnie N., Alicia S. Arrigoni, and Andrew C. Wilcox, 2012. Impacts of Dams on Flow Regimes in Three Headwater Subbasins of the Columbia River Basin, United States. Journal of the American Water Resources Association (JAWRA) 48(5): 925‐938. DOI: 10.1111/j.1752‐1688.2012.00660.x Abstract: We compared long‐term changes in flow regimes resulting from climate change with those resulting from dams in three matched pairs of natural and modified headwater subbasins of the Columbia River. Based on the analysis of 12 flow‐regime metrics, we found that damming had minimal effect on most quantity of flow metrics, but major effect on timing of flow metrics, especially those representing “spring runoff.” In all modified subbasins, “spring runoff” metrics occurred much earlier than natural flow (up to ~44 days earlier for April‐July flows). Storage capacity modulated the magnitude of timing of flow‐metric changes, with the largest storage capacity leading to the most change. However, even in subbasins with low storage capacity, we found significant change in most timing of flow metrics. We also found that damming, especially in subbasins with higher storage capacity, overwhelmed climate variability in all basins for most flow metrics. This shows that reservoir operations need to be modified to more closely match the natural timing of flow regimes to promote positive ecologic response in modified rivers, even in basins where quantity of flow metrics have not changed substantially as a result of damming.  相似文献   
73.
ABSTRACT

The degradation dynamics and terminal residues of dufulin enantiomers were investigated in two typical corn plants. A convenient and precise chiral method by high-performance liquid chromatography coupled with tandem triple quadrupole mass spectrometry (HPLC/MS/MS) using a Chiralpak IC column was developed and validated for measuring dufulin enantiomers in corn plants and corn. The two enantiomers of dufulin quickly dissipated in the corn plant, and no noticeable stereoselectivity was observed during degradation or in the final residues. After 30% rac-dufulin wettable powder with a 1- to 1.5-fold dose of the recommended value was sprayed two to three times on corn plants, the residue levels of S-(+)-dufulin and R-(-)-dufulin in corn from both sites were lower than or equal to 0.0520 mg kg–1 on days 7, 14 and 21 after the last application. The dietary risk assessment indicated that dufulin did not exhibit obvious dietary health risks in corn samples when good agricultural practices were implemented. The findings from this study may be used to better understand the chiral profiles of dufulin in the environment and the effect of dufulin residues in corn on health.  相似文献   
74.
ABSTRACT: A combination pumped storage reservoir system was simulated by modifying the WRE deep reservoir model. Each of the two reservoirs was described by a copy of the WRE model program, the two programs were converted into subroutines and were called upon alternately by a main program. Operationally, the contributing reservoir, i.e., the reservoir from which flow was discharged, was simulated for one execution interval (1 hour), followed by simulating the receiving reservoir for the same execution interval. The main program directed the discharge temperature of the contributing reservoir for each execution interval as input for simulating the receiving reservoir. The two subroutines were run in this interactive mode for a simulation period of one year. Two simulations, labeled “Pump” and “Net,” were effected and differed basically in the distribution of flow volumes exchanged between the reservoirs. In the ‘Pump’ simulation the total hourly flow volumes were distributed into appropriate horizontal layers of the lakes as determined by temperature-density relationships, i.e., the pumped discharges were distributed into the upper lake and the generation discharges were distributed into the lower lake. In the ‘Net’ simulation only the net daily discharges (daily difference between pump-back and generation at the upper dam), distributed uniformly over 24 hours, were mixed into the horizontal layers of the two lakes. Both simulations produced annual thermal regimes that were apparently within reason for the geographical area and the nature of the input data. However, neither accurately reflected a generalized conditions for the reservoirs because the Pump simulation reflected conditions in the forebay and tailrace of the Upper dam while the Net simulation reflected conditions of the remaining parts of the reservoirs.  相似文献   
75.
The food sector and health sector become more and more intertwined. This raises many possibilities, but also questions. One of them is the question of what the implication is for public trust in food and health issues. In this article, I argue that the products on the interface between food and health entails some serious questions of trust. Trust in food products and medical products is often based upon a long history of rather clear patterns of mutual expectations, yet these expectations are not similar in both sectors. As long as the food sector and health sector remain distinct, these differences will not lead to problems of trust, yet when new products are introduced, like functional foods or personalized dietary advices, trust can be threatened. To prevent this, we need clarity with regard to what we can expect of these new products and of whom to expect what in this situation. This requires not␣only adequate information on operating procedures, but also a profound debate␣on responsibilities and the explication and interpretation of moral values and norms.  相似文献   
76.
After a century of major technicaladvance, essentially achieved by and for theindustrialized countries, the evolution of thefood sector in southern countries should nolonger be thought of in terms of a ``headlongpursuit.'' In the present context of demographicgrowth, urbanization, poverty and disparities,environmental degradation, and globalization oftrade, new priorities have emerged, and newethical questions have been raised, mainlyrelated to sustainability and equity. Thispaper analyses these ethical concerns in thefollowing terms: can the model of food sectordevelopment initiated by the industrializedcountries be applied to the entire world on asustainable and equitable basis, given theeffects of this development with regard to theenergy consumed, the changes in dietarybehavior and related nutritional problems, thenew demands in terms of food safety, thequestions of biodiversity, ownership ofknowledge, cultural identities, gender issues,and Man's relationship to food and Nature?  相似文献   
77.
总N—亚硝基化合物接触量与胃癌死亡率的生态学相关性   总被引:2,自引:0,他引:2  
吴永宁  王绪卿 《环境化学》1997,16(2):125-129
在胃癌高发区福建省长乐县和低发区山东省崂山县和随机选择近60名35-64岁男性一,以份饭法收集24h膳食和12h尿液,测定总N-亚硝基人合物(TNOC)含量,计算膳食摄入量和尿中排出量人群日均膳食摄往我为7.074.31μmol,低发区为4.07±3.67μmol,P〈0.001;12h尿中排出量高发区为113±0.61μmol,低发区为0.34±0.27μmol,P〈0.001;尿中排出量与膳食  相似文献   
78.
Ecological perspective on water quality goals   总被引:32,自引:0,他引:32  
The central assumption of nonpoint source pollution control efforts in agricultural watersheds is that traditional erosion control programs are sufficient to insure high quality water resources. We outline the inadequacies of that assumption, especially as they relate to the goal of attaining ecological integrity. The declining biotic integrity of our water resources over the past two decades is not exclusively due to water quality (physical/chemical) degradation. Improvement in many aspects of the quality of our water resources must be approached with a much broader perspective than improvement of physical/chemical conditions. Other deficiencies in nonpoint pollution control programs are discussed and a new approach to the problem is outlined.  相似文献   
79.
Abstract

This study aims to establish the relationship between the consumption of certain foods and the presence of organochlorine pesticides in human milk. A total of 167 samples of breastmilk were collected. Sample analysis was carried out by gas chromatography with electron capture detector. Pesticide concentrations (op’DDT, pp’DDT, pp’DDE, Σ-DDT, HCB, β-HCH) were grouped by consumption level of fish, dairy products, meat, eggs, and seafood and then were compared to each other. The odds ratio (OR) was calculated between the concentration of pesticides (higher and/or lower than median) and the exposure variable (high consumption). The results indicated low median concentrations of HCB, β???HCH, op’DDT and pp’DDT, whose fluctuations and trends between different frequencies of food consumption were not significant. pp’DDE and Σ???DDT values according to the increase in consumption of fish were significantly increased. Women with high fish consumption have a higher risk of high concentrations of pp’DDE and Σ-DDT (OR: high consumption: 5.6 (1.3–23.6). A protective effect was observed in the consumption of dairy products (β-HCH and op’DDT), meat (HCB), and seafood (pp’DDT). These results suggest that it is possible that the consumption of fish, dairy products, meat, and seafood influences the presence of organochlorine pesticides in the studied population.  相似文献   
80.
用食物供给量与生产量分别表示食物的可及性与自给率,其差值可表示食物贸易量,以人均每天卡路里为单位进行的折算可以更好地反映膳食营养的变化。从食物贸易视角分析了28年来食物供需平衡状况,结果表明:(1)1986—2013年,全球食物贸易量增加1.5倍;食物总产量增加0.75倍,贸易量在总产量中的比例增加约8个百分点,相当于7.9×108 t食物进入国际市场,这成为改善膳食结构的重要因素。(2)28年来,食物可及性与自给率呈上升趋势,全球绝大部分人口已经达到最低2200 kal的营养标准。(3)食物可及性、自给率、贸易量均存在地域差异,非洲及南亚的部分国家是低值地区。(4)总体来看,全球人均每天热量与蛋白质供给量增加。低收入国家增速最快,中等收入国家增速次之,高收入国家增速最慢。但非洲、东南亚等地的一些欠发达国家仍未达到最低的营养标准,全球仍有一部分人处于营养不良状态。  相似文献   
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