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1.
Freshwater is the lifeline of a city. Shortages in urban water supply and ecological losses occur when freshwater supply capacity and demand are imbalanced. Therefore, systematic research on the risk of freshwater consumption in urban areas is urgently demanded. A scientific understanding of the risk of urban water consumption will contribute to the efficient use of freshwater resources and ensure the stability and sustainable development of cities. Taking Xiamen City as the study area, we evaluated the ecological risk of freshwater consumption scenarios in the years 2020 and 2030 using a multilevel characterization method for urban ecological risk, stepwise regression analysis, and a gray prediction model. The results of our evaluation show that freshwater consumption in Xiamen is highly correlated with the total population, the crop acreage, the proportion of secondary industry, and the treatment rate of domestic sewage. In the 2020 and 2030 scenarios, freshwater consumption in Xiamen City is predicted to increase. Meanwhile, with the construction of water conservancy facilities, the supply capacity of freshwater in Xiamen City will be greatly improved. Therefore, the ecological impacts of freshwater consumption in the 2020 and 2030 scenarios were at the middle and low levels. In this study, the validity of the multilevel characterization method described herein for urban ecological risk has been confirmed. However, calculation of scenario probability is a difficult problem in the framework of this method, and future research should address this issue.  相似文献   

2.
种衣剂中使用的杀虫剂会影响鸟类对种子的消耗量,从而影响鸟类的实际暴露风险。虽然量化这种对消耗量的影响目前不被考虑在环境风险评估中,但这是一个潜在的选择,例如在比较不同农药的暴露风险时应予以考虑。这种方法可以突出用于防止鸟类服用致死或亚致死剂量的杀虫剂。为了制定一个标准,我们在已建立的笔试方法的基础上开发了一个室内测试程序,包括饥饿期的“两选择”和“无选择”阶段。测试期间采用动物福利的最高标准。利用统计方法确定最合适的重复次数并分析最终结果。杀虫剂对种子消耗量的影响用处理后种子与未处理种子消耗的比率表示。该消耗因子可作为种子处理的鸟类风险评估中的回避因子。 作为案例,我们提出了一个获得绿雀(Carduelis chloris)和日本鹌鹑(Coturnix japonica)对未处理和使用杀真菌剂处理的油菜籽(Brassica napus)的种子和特定物种消耗量因子的试验程序。总体来说,两种鸟类的体质都没有受到试验程序的负面影响。试验程序适用于显示预期消耗模式的差异,例如在“两选择”试验中比在“无选择”试验中对经过杀真菌剂处理的种子有更高的避免性。而种子消耗量在不同物种和杀真菌剂处理组有差别,这使得我们可以对不同杀真菌剂的规避效应进行排序。使用本文所提出的标准程序可以针对更多鸟类物种得到具有可比性的农药和物种特定的消费因子。  相似文献   

3.
4.
The endogenous rhythm of oxygen consumption in juvenile spotted sea bass (Lateolabrax sp.) was measured to test the effects of sudden changes in salinity on the metabolic activity. Mean oxygen consumption rates of this euryhaline fish decreased by 13.5 to 16.0% and 25.3 to 36.4% when they were transferred from 31.5 to 15‰ seawater and to fresh water (0‰), respectively. The maximum rate of oxygen consumption was observed between 18:00 and 19:00 hrs local time, 1 to 2 h before sunset, even though they were kept in constant darkness. The peaks of oxygen consumption occurred in 23.2- and 23.3-h intervals, which correspond with a circadian rhythm, as revealed by maximum entropy spectral analysis. A markedly weakened rhythm in oxygen consumption occurred from 8 to 10 d after onset of the experiments. This study indicates that spotted sea bass can withstand sudden drops in salinity from 31.5‰ to fresh water, and yet maintain a regular though somewhat dampened endogenous rhythm of oxygen consumption. Received: 16 June 1997 / Accepted: 3 February 1998  相似文献   

5.
The purpose of this paper is to provide a theoretical bridge between the many-commodity general equilibrium models and the simpler one good-one pollutant models used in environmental economics. The interest is in determining the conditions that will permit a vector of pollutants (or goods) to be treated as if it were only one quantity, the amount of environmental pollution (or consumption). A general equilibrium model is constructed and the concepts of separability and functional structure are applied to examine the requirements for consistent aggregation. It is shown that this aggregation process may in general produce two entirely different sets of aggregate measures of pollution and consumption. This result is of theoretical and empirical significance. Alternative criteria for aggregation suggest that the aggregation depends upon very stringent features of the economy concerned.  相似文献   

6.
Poor biodegradability and insufficient carbon source are discovered from influent. Influent indices presented positively normal distribution or skewed distribution. Average energy consumption of WWTPs in Taihu Basin was as high as 0.458 kWh/m3. Energy consumption increases with the increase in influent volume and COD reduction. The total energy consumption decreases with the NH3-N reduction. The water quality and energy consumption of wastewater treatment plants (WWTPs) in Taihu Basin were evaluated on the basis of the operation data from 204 municipal WWTPs in the basin by using various statistical methods. The influent ammonia nitrogen (NH3-N) and total nitrogen (TN) of WWTPs in Taihu Basin showed normal distribution, whereas chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended solid (SS), and total phosphorus (TP) showed positively skewed distribution. The influent BOD5/COD was 0.4%–0.6%, only 39.2% SS/BOD5 exceeded the standard by 36.3%, the average BOD5/TN was 3.82, and the probability of influent BOD5/TP>20 was 82.8%. The average energy consumption of WWTPs in Taihu Basin in 2017 was 0.458 kWh/m3. The specific energy consumption of WWTPs with a daily treatment capacity of more than 5 × 104 m3 in Taihu Basin was stable at 0.33 kWh/m3. A power function relationship was observed between the reduction in COD and NH3-N and the specific energy consumption of pollutant reduction, and the higher the pollutant reduction is, the lower the specific energy consumption of pollutant reduction presents. In addition, a linear relationship existed between the energy consumption of WWTPs and the specific energy consumption of influent volume and pollutant reduction. Therefore, upgrading and operation with less energy consumption of WWTPs is imperative and the suggestions for Taihu WWTPs based on stringent discharge standard are proposed in detail.  相似文献   

7.
Narwani A  Mazumder A 《Ecology》2010,91(12):3441-7; discussion 3503-14
The effect of species diversity on ecosystem function is commonly studied within a single trophic level, but less is known about how resource diversity affects species interactions between trophic levels. We conducted a grazing experiment to determine how resource species diversity affects rates of consumption by three species of freshwater zooplankton consumers. We measured the effect of resource diversity on rates of consumption for several resource community compositions. These compositions varied in terms of palatability for the consumers. The effect of resource diversity on consumption rates depended on the diet breadth of the consumer species (from specialist to generalist) and the community composition of resources. Overall, high resource diversity commonly caused a decline in consumption rates of consumers. The most selective grazer showed reduced consumption for nearly all community compositions, whereas the most generalist grazer showed accelerated consumption when all resource species were palatable. Our results demonstrate that resource species diversity can modulate rates of consumption through the action of multiple different mechanisms.  相似文献   

8.
Summary During mating the males of the bushcricket Poecilimon veluchianus transfer a large spermatophore of about a quarter of their body weight to the female. Such nuptial feeding is often thought to function as paternal investment by increasing the fitness of the male's offspring. According to an alternative, though not mutually exclusive, hypothesis, the size of the spermatophore is maintained because of its function as a sperm protection device. In this case the cost to the male should be classified as mating effort. To discriminate between these two hypotheses we measured the duration of sperm transfer into the female spermatheca and the time taken for spermatophore consumption. A comparison of durations revealed that spermatophore consumption interferes with the process of sperm transfer (Fig. 4). There was no significant effect of spermatophore consumption on number of eggs laid, weight of eggs or absolute weight of hatched larvae. The relative dry weight of hatched larvae, however, was increased as a result of spermatophore consumption (Table 1). Thus spermatophylax size is adjusted in accordance with a sperm protection function and the spermatophylax therefore represents mating effort. The increase in relative dry weight indicates that there may also be a paternal investment effect of the spermatophylax, if the offspring that benefit from spermatophylax materials are fathered by the donating male. Correspondence to: K. Reinhold  相似文献   

9.
The ecological footprint (EF) is a method for measuring sustainable development through ecological impact. A methodology is presented for predicting urban ecological footprints. Urban energy use and natural resource consumption were analyzed to calculate an EF based on land type (arable, pasture, forest, fossil energy land, built-up area and water area) and consumption (food, housing, transportation, goods, services and waste). The result was then compared with the local ecological carrying capacity to develop criteria for sustainable ecological footprints. Case studies of four cities in China (Guangzhou, Ningbo, Suzhou and Yangzhou) illustrate the urban EF approach. The time series of EF in a case study of Guangzhou for 1991–2001 was analyzed and the consumption–land-use matrix of urban EF was established. The results show that the cities are ecologically unsustainable, with average ecological conflicts per capita of more than 2 ha. The urban EF method is useful to measure urban sustainable development and provides policy proposals for decision-making. However, the EF method still has limitations and weaknesses.  相似文献   

10.
This paper studies the maximin paths of the canonical Dasgupta–Heal–Solow model when the stock of natural capital is a direct argument of well-being, besides consumption. Hartwick's rule then appears as an efficient tool to characterize solutions in a variety of settings. We start with the case without technical progress. We obtain an explicit solution of the maximin problem in the case where production and utility are Cobb–Douglas. When the utility function is CES with a low elasticity of substitution between consumption and natural capital, we show that it is optimal to preserve forever a critical level of natural capital, determined endogeneously. We then study how technical progress affects the optimal maximin paths, in the Cobb–Douglas utility case. On the long run path of the economy capital, production and consumption grow at a common constant rate, while the resource stock decreases at a constant rate and is therefore completely depleted in the very long run. A higher amenity value of the resource stock leads to faster economic growth, but to a lower long run rate of depletion. We then develop a complete analysis of the dynamics of the maximin problem when the sole source of well-being is consumption, and provide a numerical resolution of the model with resource amenity. The economy consumes, produces and invests less in the short run if the resource has an amenity value than if it does not, whereas it is the contrary in the medium and long runs. However, and without surprise, the resource stock remains for ever higher with resource amenity than without.  相似文献   

11.
Water footprint is an indicator showing the consumption impact on environment with water equivalent, which allows a detailed quantification of water use directly and indirectly in sectors for the domestic and abroad final consumption. This paper presents a framework of calculating national water footprint (NWF) with input–output method on China 2002. The results indicated that the NWF of China was 381 m3/cap yr in 2002. A new indicator termed as national water footprint intensity (NWFI) is also derived from NWF to evaluate the water consumption intensities of different sectors. Then the evaluation of virtual water trade in sectors is followed, the results of which give a detailed quantification of net virtual water import of sectors, verifying that China is a net virtual water exporter concerning the whole national sectors, which is different from the previous studies. Finally, it is suggested that the sectors with high NWFI and volume of net virtual water export should be regarded as the priority of Chinese water-saving strategy.  相似文献   

12.
We estimate a model of vehicle choice and kilometers driven to analyze the long-run impacts of fuel conservation policies in the Indian car market. We simulate the effects of petrol and diesel fuel taxes and a diesel car tax, taking into account their interactions with the pre-existing petrol fuel tax and car sales taxes. At levels sufficient to reduce total fuel consumption by 7%, the increased diesel and petrol fuel taxes both yield deadweight losses (net of externalities) of about 4 (2010) Rs./L. However, at levels sufficient to reduce total fuel consumption by 2%, the increased petrol fuel tax results in a deadweight loss per liter of fuel conserved that is greater than that caused by the diesel fuel tax. This reflects both the high pre-existing tax on petrol fuel and the high own-price elasticities of fuel demand in India. A tax on diesel cars that results in the same diesel market share as the large diesel fuel tax actually has a negative deadweight loss per liter of fuel conserved. The welfare effects of all three policy instruments are positive, once the external benefits of reducing fuel consumption are added to the excess burden of taxation.  相似文献   

13.
• Fuel consumption (FC) from LDPVs is measured using on-board diagnostic method (OBD). • The FC of the OBD is 7.1% lower than that of the carbon balance results. • The discrepancy between the approved FC and real-world FC is 13%±18%. • There is a strong relationship (R2=0.984) between the average speed and relative FC. An increasing discrepancy between real-world and type-approval fuel consumption for light-duty passenger vehicles (LDPVs) has been reported by several studies. Normally, real-world fuel consumption is measured primarily by a portable emission measurement system. The on-board diagnostic (OBD) approach, which is flexible and offers high-resolution data collection, is a promising fuel consumption monitoring method. Three LDPVs were tested with a laboratory dynamometer based on a type-approval cycle, the New European Driving Cycle (NEDC). Fuel consumption was measured by the OBD and constant-volume sampling system (CVS, a regulatory method) to verify the accuracy of the OBD values. The results of the OBD method and the regulatory carbon balance method exhibited a strong linear correlation (e.g., R2 = 0.906-0.977). Compared with the carbon balance results, the fuel consumption results using the OBD were 7.1%±4.3% lower on average. Furthermore, the real-world fuel consumption of six LDPVs was tested in Beijing using the OBD. The results showed that the normalized NEDC real-world fuel consumption of the tested vehicles was 13%±17% higher than the type-approval-based fuel consumption. Because the OBD values are lower than the actual fuel consumption, using a carbon balance method may result in a larger discrepancy between real-word and type-approval fuel consumption. By means of the operating mode binning and micro trip methods, a strong relationship (R2 = 0.984) was established between the average speed and relative fuel consumption. For congested roads (average vehicle speed less than 25 km/h), the fuel consumption of LDPVs is highly sensitive to changes in average speed.  相似文献   

14.
M. Jawed 《Marine Biology》1973,21(3):173-179
The rates of oxygen consumption in relation to oxygen tension, temperature, salinity and body size were determined for Archaeomysis grebnitzkii Czerniavsky and Neomysis awatschensis (Brandt). Oxygen uptake was regulated by both species down to an oxygen tension of about 50 mm Hg (30% of saturation value); below this level, it was related to the oxygen tension in the medium. Oxygen tension below 20 mm Hg was lethal. A statistically significant interaction was noted for the effects of species, temperature, and salinity. In general, oxygen-uptake rate decreased with decreasing salinity in both species. The effect of size is expressed as a power function of body weight. The regression coefficients of oxygen consumption on body weight, 0.70 for A. grebnitzkii and 0.62 for N. awatschensis, were found to be significantly different from each other.Contribution No. 726 from the Department of Oceanography, University of Washington, Seattle, USA.  相似文献   

15.
北京和上海市居民冬夏两季饮用水消费习惯   总被引:1,自引:0,他引:1  
饮用水是人体暴露于有毒物质的重要暴露源,为了定量描述饮用水中污染物对暴露人群所造成的危害,世界各国的科学家们对饮用水的健康风险评价做了大量的研究.通常,健康风险评价需要污染物毒理学数据和暴露人群的暴露剂量数据.目前,针对很多的有毒污染物,国际上已经建立了应用于健康风险评价的毒理学数据库,同时积累了大量可用的有效数据.而对于暴露人群的暴露剂量数据,则是健康风险评价所要研究的重点.正确估计暴露人群的暴露剂量需要消费者提供大量的消费信息.例如,暴露人群每天消费的饮用水水量.美国环保局(EPA)认为成人每天消耗的饮用水水量为2L·d-1,此外,饮用水的消耗量会随着暴露人群的身体活动状况和所处环境状况(温度,湿度等)的改变而改变.目前,许多研究都是关于饮用水消费信息的,总体来讲这些研究结果基本上与美国环保局所采用的饮水消耗数据相一致.需要说明的是中国居民有完全不同于西方人的饮用水消费方式,如果在进行中国居民饮用水健康风险评价过程中应用美国环保局的假设会带来较大的不确定性.饮用水健康风险评价工作在我国开展并不多,尤其缺少中国居民饮用水消费习惯的数据库.这些客观条件使得在我国进行饮用水健康风险评价时只能从基础做起,积累有效的数据.本研究以北京和上海两座城市居民为研究对象,2002年到2004年分冬夏两季分别进行了4次饮用水消费习惯调查.研究采用随机入户方式(2004年至2005年),与中央电视台-索福瑞联合调查有限公司合作进行.参加调查的家庭从中央电视台入户收视率调查的基础数据库中随机抽取,在抽取过程中兼顾了不同城区、年龄结构、知识结构、收入水平等因素.研究表明,北京和上海居民冬夏两季的日均饮水量分别为2.2L·d-1、1.7L·d-1、2.0L·d-1和1.8L·d-1,这一结果和美国环保局的假设基本一致.同时本研究考察了性别、年龄、职业和季节对应用水消费习惯的影响.研究表明,日均饮水量随年龄的增加有增加的趋势,这一趋势在北京的夏季调查中趋势明显(p=0.01);男性的日均饮用水量大于女性,在上海冬季和夏季调查中均存在显著的差异(冬季:p=0.01;夏季:p=0.04);季节也同样影响被访者的日均饮水量,但是在4次调查中均未发现显著性差异.在北京冬季和夏季的调查中均发现了工作地点对饮用水消费习惯的显著影响(夏季p=0.01和冬季p=0.00).研究同样考察了居民饮用水消费类型,调查结果表明,煮沸后的自来水是中国居民最主要的日常饮品(上海夏季:58.3%;上海冬季67.9%;北京夏季:42.7%;北京冬季:60.0%).同时消费桶装纯净水的被访者也占有相当的比重(上海夏季:36.2%;上海冬季:24.7%;北京夏季:30.7%;北京冬季:60.0%).研究同时表明,在中国居民的日常生活中牛奶和豆奶已经成为重要的日常饮品.极少量的居民(北京夏季:10.7%;北京冬季5.7%;上海夏季1.2%;上海冬季0.6%)有直接饮用自来水的习惯.研究表明滞留水(在自来水水管中滞留6h以上的自来水)是对人体健康影响最大的水,而在我们的调查中,中国居民几乎不直接饮用滞留水.当前,饮用水健康风险评价在世界范围内蓬勃展开,但是这一技术在我国还处于起步阶段.本研究作为饮用水健康风险评价的前期工作,为其在中国的进一步发展提供了基础性的数据.  相似文献   

16.
饮用水是人体暴露于有毒物质的重要暴露源,为了定量描述饮用水中污染物对暴露人群所造成的危害,世界各国的科学家们对饮用水的健康风险评价做了大量的研究. 通常,健康风险评价需要污染物毒理学数据和暴露人群的暴露剂量数据. 目前,针对很多的有毒污染物,国际上已经建立了应用于健康风险评价的毒理学数据库,同时积累了大量可用的有效数据. 而对于暴露人群的暴露剂量数据,则是健康风险评价所要研究的重点. 正确估计暴露人群的暴露剂量需要消费者提供大量的消费信息. 例如,暴露人群每天消费的饮用水水量. 美国环保局(EPA)认为成人每天消耗的饮用水水量为2L·d-1,此外,饮用水的消耗量会随着暴露人群的身体活动状况和所处环境状况(温度,湿度等)的改变而改变. 目前,许多研究都是关于饮用水消费信息的,总体来讲这些研究结果基本上与美国环保局所采用的饮水消耗数据相一致. 需要说明的是中国居民有完全不同于西方人的饮用水消费方式,如果在进行中国居民饮用水健康风险评价过程中应用美国环保局的假设会带来较大的不确定性. 饮用水健康风险评价工作在我国开展并不多,尤其缺少中国居民饮用水消费习惯的数据库. 这些客观条件使得在我国进行饮用水健康风险评价时只能从基础做起,积累有效的数据. 本研究以北京和上海两座城市居民为研究对象,2002年到2004年分冬夏两季分别进行了4次饮用水消费习惯调查. 研究采用随机入户方式(2004年至2005年),与中央电视台-索福瑞联合调查有限公司合作进行. 参加调查的家庭从中央电视台入户收视率调查的基础数据库中随机抽取,在抽取过程中兼顾了不同城区、年龄结构、知识结构、收入水平等因素. 研究表明,北京和上海居民冬夏两季的日均饮水量分别为2.2L·d-1、1.7L·d-1、2.0L·d-1和1.8L·d-1,这一结果和美国环保局的假设基本一致. 同时本研究考察了性别、年龄、职业和季节对应用水消费习惯的影响. 研究表明,日均饮水量随年龄的增加有增加的趋势,这一趋势在北京的夏季调查中趋势明显(p=0.01);男性的日均饮用水量大于女性,在上海冬季和夏季调查中均存在显著的差异(冬季:p=0.01;夏季:p=0.04);季节也同样影响被访者的日均饮水量,但是在4次调查中均未发现显著性差异. 在北京冬季和夏季的调查中均发现了工作地点对饮用水消费习惯的显著影响(夏季p=0.01 和冬季p=0.00). 研究同样考察了居民饮用水消费类型,调查结果表明,煮沸后的自来水是中国居民最主要的日常饮品(上海夏季:58.3%;上海冬季67.9%;北京夏季:42.7%;北京冬季:60.0%). 同时消费桶装纯净水的被访者也占有相当的比重(上海夏季:36.2%;上海冬季:24.7%;北京夏季:30.7%;北京冬季:60.0%). 研究同时表明,在中国居民的日常生活中牛奶和豆奶已经成为重要的日常饮品. 极少量的居民(北京夏季:10.7%;北京冬季5.7%;上海夏季1.2%;上海冬季0.6%)有直接饮用自来水的习惯. 研究表明滞留水(在自来水水管中滞留6h以上的自来水)是对人体健康影响最大的水,而在我们的调查中,中国居民几乎不直接饮用滞留水. 当前,饮用水健康风险评价在世界范围内蓬勃展开,但是这一技术在我国还处于起步阶段. 本研究作为饮用水健康风险评价的前期工作,为其在中国的进一步发展提供了基础性的数据.  相似文献   

17.
A high-pressure water-circulation system is described which enables fish (or other animals breathing water) to be maintained at pressures up to 101 atm for at least one month. A typical experiment, measuring the oxygen consumption of the eelAnguilla anguilla over a period of 31 d, revealed a metabolic acclimation to pressure in this fish. This system has numerous advantages; e.g. it is possible to reproduce in situ environmental conditions at depth, thus enabling the study of the problems of pressure adaptation, and also to simulate vertical migrations of animals, allowing the study of associated physiological phenomenon.  相似文献   

18.
Workers in social groups of honeybees (Apis mellifera L.) synchronize their individual free-running circadian rhythms to an overall group rhythm. By monitoring the activity of bees by recording the oxygen consumption and intragroup temperature, it is shown that the rhythm coordination is in part achieved by temperature fluctuations as an intragroup Zeitgeber. Trophallaxis was shown to have only a minor (if any) effect on circadian rhythm synchronization. A model incorporating a feed back loop between temperature and activity can plausibly explain the observed synchronization of individual rhythms in social groups as a self-organization phenomenon. Correspondence to: R.F.A. Moritz  相似文献   

19.
陈惠娟  千怀遂 《生态环境》2006,15(6):1331-1336
选取了北京、上海、广州三个不同地理纬度、经济较为发达的代表性城市作为研究对象,应用多项式模型把气候耗水量从水资源消费总量中分离出来,用统计分析的方法探讨三个城市水资源消费变化及其与经济和气候的关系。研究表明:城市万元GDP用水量与经济水平有明显的对数相关关系,一般都随经济水平的提高而不断下降,三个城市中,上海的水资源利用率最高,广州居中,北京最低。温度是影响城市气候耗水量的主要气候因子,在1986—1991年,三个城市的气候耗水量与温度的相关性不明显,自1992年以来,气候耗水量与温度距平值的波动趋势愈来愈密切,这说明随着经济的发展和人民生活水平的提高,城市水资源消费与温度的关系越来越密切。  相似文献   

20.
Cadmium (Cd) contamination has been reported to be a problem for the safe usage of Panax notoginseng (Sanchi); thus, it is necessary to elucidate the Cd accumulation in Sanchi and to assess its associated health risk. Samples were collected from major producing areas in Yunnan, China. The average concentration of Cd in Sanchi was 0.43 mg/kg, which exceeds the standard level for herbal medicine in China (0.3 mg/kg). A stepwise regression analysis showed that zinc and the pH were the related factors that most significantly impacted Cd in Sanchi roots. The hazard quotient values were estimated as 0.0010 (men) and 0.0012 (women) for consumers taking preparations and were 0.011 (men) and 0.013 (women) for consumers taking health products, implying that there is no non-carcinogenic hazard associated with Sanchi consumption. However, a Monte Carlo simulation showed that approximately 0.80 % of male and 1.02 % of female consumers via drug consumption and 36.28 % of male and 41.87 % of female consumers via health product consumption had an exposure exceeding the acceptable daily intake (ADI) of Cd from drugs (1 % of the total oral ADI as suggested by the World Health Organization). These people should control their oral Cd intake from both Sanchi consumption and diet as a whole.  相似文献   

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