农场给水处理方法探讨

农场供水是一种特殊给水,供水管道中的“结垢”现象是处理的难题,本文在调查分析的基础上,比较几种处理方法,提出药剂软化法,并施以相应的工程,使其达标排放。     

热重法研究煤燃烧添加剂的催化效果

采用热量分析法研究了江西丰城劣质煤燃烧特性和稀土助燃添加剂对该煤的催化燃烧作用效果，比较了劣质煤在加入稀土助燃添加剂前后燃烧峰值温度、燃烧反应活化能、反应级数的变化。结果表明，在劣质煤中加入５％的稀土助燃添加剂后，能显著加快煤燃烧速率，降低燃烧反应活化能，从而产生助燃效果，进一步分析了稀土助燃添加剂的催化作用机理。     

双酚A和邻苯二甲酸二正丁酯在纸类上的吸附特性研究

采用序批式实验,考察了报纸对双酚A(BPA)和邻苯二甲酸二正丁酯(DnBP)的吸附能力,用Freundlich、Langmuir、Dubinin-Radushkevich(D-R)、Flory-Huggins(F-H)、BET、Temkin 6种吸附等温线模型对实验数据进行了拟合.并选择了回归系数(R2)、均方根差(RMSE)和卡方检验(X2检验)3种非线性回归方法评价了模型拟合度.结果表明,Freundlich和Temkin吸附等温线模型能很好地描述BPA和DnBP在纸类表面的吸附,BPA和DnBP的R2均大于0.95(P<0.01),RMSE和X2分别小于0.05和0.02;吸附能力与吸附质的疏水性呈正相关.由D-R和F-H吸附等温线模型拟合结果可知,BPA和DnBP的吸附平均自由能分别为1.484和1.609 kJ/mol;Gibbs自由能分别为-6.559和-7.021 kJ/mol.说明BPA和DnBP在纸类上的吸附为自发的物理吸附.BPA和DnBP在纸类上的Freundlich吸附常数k分别为0.147和0.502 mg(1-n)·L"·g-1,均高于文献报道的底泥等的吸附常数,说明生活垃圾填埋场中纸类会阻碍BPA和DnBP的迁移和生物可利用性.     

Effect of working time on environmental pressures: empirical evidence from EU-15, 1970–2010

There is growing interest in the correlation between working time and environmental pressures, but prior empirical studies mostly focused on static methodologies. This article used dynamic panel regression approaches to examine and compare the relationship among western, southern, and northern European countries over the period 1970–2010, and proved the existence of strongly significant relationships in all models. Furthermore, this article detected the relationship between working hours and environmental indicators (carbon emission and energy use) at different phases. We contribute to a further understanding of the environmental effects of the working time reduction policy by comparing the differences among various periods and country groups in a system generalized method of moments (GMM) dynamic framework.     

Spatial scaling between leaf area index maps of different resolutions

We developed algorithms for spatial scaling of leaf area index (LAI) using sub-pixel information. The study area is located near Liping County, Guizhou Province, in China. Methods for LAI spatial scaling were investigated on LAI images with 960 m resolution derived in two ways. LAI from distributed calculation (LAID) was derived using Landsat ETM+ data (30 m), and LAI from lumped calculation (LAIL) was obtained from the coarse (960 m) resolution data derived through resampling the ETM+ data. We found that lumped calculations can be considerably biased compared to the distributed (ETM+) case, suggesting that global and regional LAI maps can be biased if surface heterogeneity within the mapping resolution is ignored. Based on these results, we developed algorithms for removing the biases in lumped LAI maps using sub-pixel land cover-type information, and applied these to correct one coarse resolution LAI product which greatly improved its accuracy.     

Effects of prenatal exposure to bisphenols on newborn leucocyte telomere length: a prospective birth cohort study in China

Environmental Science and Pollution Research - Telomere length (TL) at birth is related to diseases that may arise in the future and long-term health. Bisphenols exhibit toxic effects and can cross...     

Recycling EDTA solutions used to remediate metal-polluted soils

The objective of this research was to investigate the recycling of ethylenediamine-tetraacetic acid (EDTA) used for the removal of trace metals from contaminated soils. We successfully used Na2S combined with Ca(OH)2 to precipitate the trace metals allowing us to recycle the EDTA. The results of batch and column leaching experiments show that both Ca-EDTA and Na-EDTA are powerful chelating agents with a similar soil remediation potential. The major advantage of Ca-EDTA is the preservation of soil organic matter. We found that Na2S was capable of separating the metals Cd, Cu and Pb from EDTA; however, the precipitation of Zn required the addition of Ca(OH)2. After reusing the reclaimed EDTA seven times, over a 14-day period, EDTA reagent losses ranged from 19.5% to 23.5%. Successive washing cycles enhanced the removal of trace metals from contaminated soils. The metal sulfide precipitates contain high concentrations of metals and could potentially be recycled.     

Effects of golden shiner (Notemigonuscrysoleucas ) nest association on host pumpkinseeds (Lepomisgibbosus ): evidence for a non-parasitic relationship

The reproductive success of male parental pumpkinseeds, Lepomisgibbosus, was studied in relation to the use of their nests by spawning golden shiners, Notemigonuscrysoleucas. The brood size of pumpkinseeds with and without golden shiner's young was compared in a field population. Mean egg and larval numbers of pumpkinseeds did not differ between broods with and without shiners, suggesting that shiners had no net effect on the fitness of host pumpkinseeds. In the laboratory, however, hatching success of pumpkinseed embryos was significantly lower with shiners than without. This difference was attributable to fungal infection. Against this fitness loss, the presence of shiner larvae reduced predation on pumpkinseed larvae in laboratory experiments. Thus, two counteracting mechanisms are proposed to account for no observed net effect on the host: (1) increased fungal infection on pumpkinseed embryos and (2) decreased predation on pumpkinseed young. Received: 10 January 1997 / Accepted after revision: 9 August 1997     

Wild meat trade over the last 45 years in the Peruvian Amazon

The trade in wild meat is an important economic component of rural people's livelihoods, but it has been perceived to be among the main causes of the decline of wildlife species. Recently, the COVID-19 pandemic has brought to light an additional concern of wildlife markets as a major human-health challenge. We analyzed data from the largest longitudinal monitoring (1973–2018) of the most important urban wild-meat markets in Iquitos, Peru, to examine the trends in and impacts of these markets on people's livelihoods. Over the last 45 years, wild meat sales increased at a rate of 6.4 t/year (SD 2.17), paralleling urban population growth. Wild meat sales were highest in 2018 (442 t), contributing US$2.6 million (0.76%) to the regional gross domestic product. Five species of ungulates and rodents accounted for 88.5% of the amount of biomass traded. Vulnerable and Endangered species represented 7.0% and 0.4% of individuals sold, respectively. Despite growth in sales, the contribution of wild meat to overall urban diet was constant: 1–2%/year of total meat consumed. This result was due to greater availability and higher consumption of cheaper meats (e.g., in 2018, poultry was 45.8% cheaper and was the most consumed meat) coupled with the lack of economic incentives to harvest wild meat species in rural areas. Most wild meat was sold salted or smoked, reducing the likelihood of foodborne diseases. Community-based wildlife management plans and the continued trade bans on primates and threatened taxa may avoid biodiversity loss. Considering the recent COVID-19 pandemic, future management plans should include potential viral hosts and regulation and enforcement of hygiene practices in wild-meat markets.     

Ammonia production and kinetic properties of glutamate dehydrogenase in the sipinculid Phascolosoma arcuatum exposed to anoxia

The amounts of total NH ₄ ⁺ detected in the external media in which Phascolosoma arcuatum had been exposed to various periods of anoxia were significantly greater than those in which the worms were exposed to normoxia for a similar period. The increased NH ₄ ⁺ production by P. arcuatum during anoxic exposure was unlikely to be due to an increased catabolism of adenine nucleotides or urea. In contrast, there were significant decreases in the concentrations of several free amino acids in the coelomic plasma and body tissues of individuals during the 48 h of anoxic exposure. The amount of NH ₄ ⁺ produced by the anoxic P. arcuatum could be accounted for by the decreases in the concentrations of aspartate or glycine. Increases in the catabolism of free amino acids (FAA), leading to the increased production of NH ₄ ⁺ , in P. arcuatum during anoxia were supported by the detection of significant changes in the kinetic properties of glutamate dehydrogenase (GDH), in the deaminating direction, from worms exposed to anoxia for 48 h. The apparent increase in the affinity of GDH from the anoxic worm to glutamate would bring about a greater deaminating activity at physiological concentrations of ths substrate. P. arcuatum used in these experiments were collected from the mangrove swamp at Mandai, Singapore between 1990 and 1993.