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81.
The concentrations and distribution of polychlorinated naphthalenes(PCNs) in the whole blood of eight typical terrestrial meat animals(chicken, duck, rabbit, pig, cattle, sheep,horse and donkey) consumed daily in our life were investigated. The total concentrations(on a liquid volume basis) of PCNs were in a range from 305 to 987 pg/L. Donkey blood contained the highest PCN concentrations. Mono-CNs were the dominant homolog group,accounting for 38%–71% PCNs. Apart from the mono-CNs and tri-CNs homolog groups, two hepta-CNs(mean: 9.5%) contributed most, followed by tetra-CNs(mean: 6.5%). The congeners CN1, 5/7, 24/14, 27/30, 52/60, 66/67, and 73 were the most abundant congeners or congener groups. The highest toxicity equivalencies(TEQs) were observed in cattle blood(117.4 fg TEQ/L) then chicken blood(117.1 fg TEQ/L). CN73 contributed 65% to total TEQs,followed by CN70(20%) and CN66/67(14%). The dietary intakes of PCNs were also estimated.Chicken meat, which forms the second largest component of meat product consumption in China, contributed most to the total TEQs(61%), followed by beef(27%) and pork(5.9%). The consumption of chicken might pose the highest risk from exposure to PCNs than other types of meat to populations who prefer to eat chicken meat.  相似文献   
82.
上海春季大气PM_1分布特征   总被引:1,自引:0,他引:1       下载免费PDF全文
利用2015年春季(3月—5月)上海地区9个大气成分站在线观测获得的地面PM_1质量浓度数据,研究该地区PM_1浓度时空分布特征。结果表明,上海地区各站PM_1污染浓度水平总体较高,整个上海地区的PM_1小时平均浓度为26.3μg?m~(-3),最大值为126.4μg?m~(-3),最小值为2.4μg?m~(-3);各站PM_1浓度的日变化分布表现为峰值类型和峰值时间不一;各站PM_1三个主要粒径段的质量浓度比值均有一定的差异,其中东滩PM_1比例最大,宝山最小;上海春季PM_1的浓度逆周末效应,可能是由于春季气象条件周期性影响。  相似文献   
83.
Production of biogas from animal wastes could lessen the problems of energy shortage and indiscriminate animal waste disposal. A study of anaerobic digestion of selected ratios of cattle, swine, and poultry wastes was carried out to evaluate their biogas yields. Cattle (C), swine (S), and poultry (P) wastes were mixed as C:S:P in the following ratios: 1:0:0 (control), 1:0:1, 4:1:3, 2:1:1, 4:3:1, and 1:1:0 by mass to obtain six samples of of 0.4 kg each, referred to as samples 1 to 6 respectively. A quantity (0.1 kg) of inoculum (obtained by pre-fermenting equal masses of poultry waste and water for 50 days under anaerobic condition) and 0.5 kg of water were added to each of the samples. The resulting slurries were digested in triplicates for 30 days in 1.3 L laboratory-scale anaerobic digesters. The volume of biogas produced was obtained by downward displacement of water in a measuring cylinder. The cumulative biogas yields of samples 1 to 6 were 332.5, 497.5, 487.5, 467.5, 457.5, and 430.0 cm3/kg slurry respectively. The cumulative biogas yields of samples 2 and 3 were significantly (p < 0.05) higher than those of the other samples but not significantly (p > 0.05) different from each other. However, the cumulative biogas yield of sample 1 was significantly (p < 0.05) lower than those of the other samples. The study revealed that a blend of equal masses of cattle and poultry wastes is optimum for biogas production.  相似文献   
84.
Abstract: The Generalized Watershed Loading Functions (GWLF) model and its ArcView interface (AVGWLF) were used to estimate and examine the components of the total nitrogen (TN) nonpoint source (NPS) load generated within New York and Connecticut (CT) watersheds surrounding Long Island Sound (LIS, the Sound). The majority of data used as model inputs were generally available from online sources, and the work involved an overall calibration to streamflow and TN data in accordance with generic guidelines recommended in the GWLF manual. The GWLF model performance for three calibration and two validation watersheds in CT was compared with results of a detailed model, Hydrological Simulation Program in Fortran, developed in a previous study. The results of the application illustrate the usefulness of the relatively simpler, less parameter‐intensive GWLF model in performing exploratory loading analysis in preparation for adaptive nutrient management in the LIS watersheds. The presented methodology is valuable for identification of priority watersheds for NPS pollution reduction and also for planning‐level evaluation of best management practices to achieve the desired reductions. It is estimated that ground‐water base flow may be the largest pathway for NPS TN to the Sound, contributing about 54% of the total NPS TN load, a finding with significant implications for LIS total maximum daily load reduction scenarios. In addition to ground water, septic systems are estimated to contribute about 17% of the total load, with the remaining TN load being mostly runoff from urban (17%), agricultural (5%), and low impact (e.g., forest) areas (6%).  相似文献   
85.
During 2006-2008, a monitoring program was conducted on 29 target compounds, including PCDD/Fs and dl-PCBs, comprising 150 randomly collected individual food samples marketed in the Region of Valencia, Spain, grouped into 8 categories (vegetables, cereals, fats and oils, eggs, milk and dairy products, fish products, meat and meat products and fish oil). For PCDD/Fs, the highest frequency of detection corresponds to 1,2,3,4,6,7,8-HpCDD, OCDD, 2,3,4,7,8-PeCDF; and PCBs 118, 105 and 156 were the more frequent dl-PCBs. The food groups presenting higher contamination, expressed as toxic equivalents (WHO-TEQs), were fish oil (6.38 pg WHO-TEQ g−1 fat), fish (1.21 pg WHO-TEQ g−1 w.w.) and milk and dairy products (0.90 pg WHO-TEQ g−1 fat). Of all analysed samples, only two fish oils presented levels higher than the EU limits for total WHO-TEQ. The average PCDD/Fs and dl-PCBs intakes were estimated as 2.86 pg WHO-TEQ kg−1 b.w. d−1 and 4.58 pg WHO-TEQ kg−1 b.w. d−1, for adults and children, respectively, using the deterministic method for chronic exposure. The main contributors to total intake for adults were fish (59%), milk and dairy products (19%), and fat and oils (9%). The average daily intake for adults (2.86 pg WHO-TEQ kg−1 b.w. d−1) is within range of TDI recommended by the WHO (1-4 pg WHO-TEQ kg−1 b.w. d−1), and slightly above the TWI and PTMI adopted by SCF and JECFA respectively.  相似文献   
86.
Across West and Central Africa, wildlife provides a source of food and income. We investigated the relation between bushmeat hunting and household wealth and protein consumption in 2 rural communities in Bioko Island, Equatorial Guinea. One village was dedicated to commercial hunting, the other trapped game primarily for food. We tested whether commercial‐hunter households were nutritionally advantaged over subsistence‐hunter households due to their higher income from the bushmeat trade and greater access to wild‐animal protein. We conducted bushmeat‐offtake surveys in both villages (captures by hunters and carcasses arriving to each village). Mammals (including threatened primates: black colobus [Colobus satanas], Preussi's guenon [Allochrocebus preussi], and russet‐eared guenon [Cercopithecus erythrotis]), birds, and reptiles were hunted. The blue duiker (Philantomba monticola), giant pouched rat (Cricetomys emini), and brush‐tailed porcupine (Atherurus africanus) contributed almost all the animal biomass hunted, consumed, or sold in both villages. Monkeys and Ogilbyi's duikers (Cephalophus ogilbyi) were hunted only by commercial hunters. Commercial hunters generated a mean of US$2000/year from bushmeat sales. Households with commercial hunters were on average wealthier, generated more income, spent more money on nonessential goods, and bought more products they did not grow. By contrast, households with subsistence hunters spent less on market items, spent more on essential products, and grew more of their own food. Despite these differences, average consumption of vegetable protein and domestic meat and bushmeat protein did not differ between villages. Our results highlight the importance of understanding the socioeconomic and nutritional context of commercial and subsistence bushmeat hunting to correctly interpret ways of reducing their effects on threatened species and to enable the sustainable offtake of more productive taxa. Contrastes en el Sustento y la Ingesta de Proteínas entre Carne de Caza de Subsistencia y Comercial en Dos Aldeas en Isla Bioko, Guinea Ecuatorial  相似文献   
87.
Todd, M. Jason, George Vellidis, R. Richard Lowrance, and Catherine M. Pringle, 2009. High Sediment Oxygen Demand Within an Instream Swamp in Southern Georgia: Implications for Low Dissolved Oxygen Levels in Coastal Blackwater Streams. Journal of the American Water Resources Association (JAWRA) 45(6):1493‐1507. Abstract: Sediment oxygen demand (SOD) is considered a critical and dominant sink for dissolved oxygen (DO) in many river systems including blackwater streams and is often poorly investigated or roughly estimated in oxygen budgets. The purposes of this study are to (1) characterize and document the magnitude and variability of SOD in representative instream swamps found on the Georgia Coastal Plain; (2) predict SOD from more readily measured parameters such as soil, sediment, and litter organic carbon; and (3) obtain an accurate representation of SOD values within this understudied habitat to help improve water quality models and the continued development of DO as an appropriate water quality standard. Results show SOD rates ranging from 0.491 to 14.189 g O2/m2/day, up to 18 times higher than values reported for southeastern sandy‐bottomed streams and suggest that instream swamps are repositories of large amounts of organic matter and are thus areas of intense oxygen demand and a major factor in determining the oxygen balance of the watershed as a whole. These areas of intense oxygen demand in relatively unimpacted areas indicate that low DO concentrations may be a natural phenomenon. SOD rates were significantly correlated (alpha = 0.05) with a number of sediment parameters, with organic carbon and total organic carbon being the best predictors of SOD rate. When developing water quality models, managers should pay closer attention to the influence of SOD as it plays a critical role in determining DO levels within instream swamps and the river system.  相似文献   
88.
基于长江流域115个雨量站1963~2013年的日降水数据,应用小波多分辨分析结合信息论的方法,揭示长江流域近51 a来日降水时空变异的多尺度特征。结果表明:空间上,流域日降水序列的变异性具有明显的局部聚集性;并沿纬向呈现出显著的非均质性,而沿经向呈现出拟均匀性;并于103°E附近存在一条明显的分界线,界线以西的日降水变异程度显著高于界限以东的;且日降水变异性与高程之间存在较强的线性相关性,而与年降水量和年降水天数之间则存在较弱的相关性。时间上,流域各站点日降水子序列对原始序列总变异的相对贡献的大小于103°E附近也存在一条明显的分界线,界线以西,各时间尺度下子序列的贡献均大于界线以东;且这种相对贡献的谱图于256 d处呈现出突变现象。此外,流域降水变异的时间尺度可分为3个不同的区间:短期的(2~16 d)、年内的(16~256 d)和年际的(大于256 d)。  相似文献   
89.
Breast milk is a noninvasive specimen to assess maternal and infant exposure to polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). In this study, 206 breast milk samples were collected from 87 participants during lactation, at <7, 15, 30, or 90 days postpartum in four cities in Korea. The total concentrations of PCBs (ΣPCB) and OCPs (ΣOCP) ranged from <LOQ to 84.0 (median: 12.1) ng g−1 lipid weight and from <LOQ to 559 (median: 144) ng g−1 lipid weight, respectively. The residue levels of these contaminants measured in our study were relatively lower than those reported for European, African and Asian populations. Within a month postpartum typically after day seven the levels of ΣPCB and ΣOCP significantly increased. Some OCP compounds were correlated with maternal age, BMI, parity, and delivery mode. Certain types of dietary habits such as seafood and noodle consumption were significantly associated with ΣPCB and ΣOCP. The estimated daily intakes (EDIs) of ΣPCB and ΣOCP were 45.2–127 ng kg−1 bw day−1 and 625–1259 ng kg−1 bw day−1 during lactation, respectively, which are lower than the threshold values proposed by the US EPA and Health Canada. The exposure of Korean infants to chlordanes via breast milk had a potential health risk which deserves further investigation.  相似文献   
90.
This paper contributes to the calling literature by using self‐determination theory—a theory that makes distinctions between different types of motivation—in order to gain a better understanding of how enacting a calling may relate both positively and negatively to well‐being. We use a daily diary method novel to the calling field and a sample with a distinctive calling, Church of England clergy. We expect daily calling enactment to relate positively to daily well‐being via more autonomous forms of motivation (intrinsic and identified motivation) and negatively via less autonomous forms (introjected motivation). Furthermore, we consider how the relationship between calling enactment and motivation may be moderated by perceived competence. The hypotheses were tested using multi‐level structural equation modeling. There was strong support for calling enactment relating positively to well‐being, and this relationship was fully mediated by intrinsic and identified motivation; the hypothesized negative pathway, from calling enactment, to introjected motivation, to well‐being, was not supported. However, perceived competence was found to moderate some of the relationships between calling and the motivation types, where calling enactment is linked to lower introjected motivation at high levels of competence. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
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