Distribution and ratios of Cs and K in control and K-treated coconut trees at Bikini Island where nuclear test fallout occurred: effects and implications

Coconut trees growing on atolls of the Bikini Islands are on the margin of K deficiency because the concentration of exchangeable K in coral soil is very low, ranging from only 20 to 80 mg kg⁻¹. When provided with additional K, coconut trees absorb large quantities of K and this uptake of K significantly alters the patterns of distribution of ¹³⁷Cs within the plant. Following a single K fertilization event, mean total K in trunks of K-treated trees is 5.6 times greater than in trunks of control trees. In contrast, ¹³⁷Cs concentration in trunks of K-treated and control trees is statistically the same while ¹³⁷Cs is significantly lower in edible fruits of K-treated trees. Within one year after fertilization (one rainy season), K concentration in soil is back to naturally low concentrations. However, the tissue concentrations of K in treated trees stays very high internally in the trees for years while ¹³⁷Cs concentration in treated trees remains very low in all tree compartments except for the trunk. Potassium fertilization did not change soil Cs availability.     

Suitable gamma energy for gamma-spectrometric determination of U in surface soil samples of a high rainfall area in India

The paper presents a systematic study on suitability of various gamma lines for monitoring of ²³⁸U activity in soil samples around a uranium mineralized zone of Kylleng Pyndengsohiong Mawthabah (Domiasiat), Meghalaya in India. The area lies in a plateau region which recieves the highest average annual rainfall (12,000 mm) in the world. The geochemical behaviour of the uranium and its daughter products at such wet climatic conditions imposes restrictions to assess ²³⁸U through gamma lines of radon decay products. Soil samples were collected from nine locations around the uranium mineralization zone for analysis. The ratio of the concentration of uranium obtained from gamma energies of radium daughter products to the 63.29 keV of ²³⁴Th was found to vary from 1.01 to 2.07, which indicates a pronounced disequilibrium between uranium and radium daughters. The results obtained from various gamma energies were validated from the data generated by Instrumental Neutron Activation Analysis (INAA) technique. The ²³⁸U activities from the two analytical methods show a well fitted regression line with correlation coefficient 0.99 which validates the reliability of 63.29 keV energy for estimation of uranium in such conditions.     

页岩气压裂返排液高效破胶剂的研究

针对页岩气开采过程中产生的非常规压裂返排液具有高粘度、高COD及高稳定性的特点,以Fe(NO3)3和Ca(Cl O)2为原料,采用化学湿法中的两步法合成了一种绿色氧化剂K2Fe O4,并对合成出的K2Fe O4进行了定量分析,得到合成的高铁酸钾产率为67.63%,纯度为93.41%。采用X衍射、红外光谱、扫描电镜及X衍射能谱,对合成的K2Fe O4进行了表征。将K2Fe O4作为某气田页岩气压裂返排液的高效破胶剂,并对影响破胶效果的因素进行了分析。确定了K2Fe O4的加量为3 000 mg/L,体系p H为11.0及反应时间为40 min的最优条件,在最优条件下,得到出水的粘度为1.4 m Pa·s,其COD、SS和色度的去除率分别为59.1%、93.3%和88.9%。通过红外光谱和扫描电镜进行了微观观察,对K2Fe O4氧化非常规压裂返排液中主要成分胍胶的过程进行了机理分析。研究还发现,K2Fe O4在还原分解后,具有比单一铁离子更强的混凝效果。因此,K2Fe O4的应用对页岩气压裂返排液的处理有深远的影响。     

Selective removal of organochlorine pesticides (OCPs) from aqueous solution by triolein-embedded composite adsorbent

A novel composite adsorbent (CA-T) was used for the selective removal of organochlorine pesticides (OCPs) from aqueous solution. The adsorbent was composed of the supporting activated carbon and the surrounding triolein-embedded cellulose acetate membrane. Scanning electron microscopy (SEM), N₂ adsorption isotherms and fluorescence methods were used to characterize the physicochemical properties of CA-T. Triolein was perfectly embedded in the cellulose acetate membrane and deposited on the surface of activated carbon. The adsorbent was stable in water and no triolein leakage was detected during the test periods. Some organochlorine pesticides (OCPs), such as dieldrin, endrin, aldrin, and heptachlor epoxide, were used as model contaminants and removed by CA-T in laboratory batch experiments. The adsorption isotherm followed the Freundlich equation and the kinetic data fitted well to the pseudo-second-order reaction model. Results also indicated that CA-T appeared to be a promising adsorbent with good selectivity and satisfactory removal rate for lipophilic OCPs from aqueous solutions when present in trace amounts. The adsorption rate and removal efficiency for lipophilic OCPs were positively related to their octanol-water partition coefficients (log K _ow). Lower residual concentrations of OCPs were achieved when compared to granular activated carbon (GAC).     

基于QUAL2K模型的鹤壁卫河水质模拟预警研究

水质预报预警对于防范水污染、降低水污染风险及其带来的损失、保障用水安全及水环境质量等具有重大意义。提出了一种基于QUAL2K模型的水质模拟预警方法,包括水质模拟预测、预警指数计算和警情确定,以海河流域鹤壁市卫河为例进行实证研究。研究结果表明:基于QUAL2K模型模拟精度分别为COD 97.7%、NH_3-N 98.5%,水质模拟效果较好;所选河段预警时段内COD基本处于无警和轻警2个级别,氨氮大多是巨警,浓度严重超标,是导致监测断面预警指数高的主要原因。     

Molecular studies on the ouabain binding site of the Na+, K+-ATPase in milkweed butterflies

Summary. The Na⁺, K⁺-ATPase of the Monarch butterfly (Danaus plexippus) is insensitive to the inhibition by cardiac glycosides due to an amino acid replacement: histidine instead of asparagine at position 122 of the α-subunit representing the ouabain binding site. By PCR amplification of the DNA sequence of this site, a PCR product of 270 bp was obtained from DNA extracted from Danainae species (Danaus plexippus, D. chrysippus, D. gillipus, D. philene, D. genutia, Tirumala hamata, Euploea spp., Parantica weiskei, P. melusine), Sphingidae (Daphnis nerii) and mimics of milkweed butterflies (Hypolimnas missipus, Limenitis archippus and L. arthemis, Nymphalidae). Analysis of the nucleotide sequences revealed that the single point mutation in the ouabain binding domain (AAC-Asn for CAC-His) was present only in Danaus plexippus, but not in the other species investigated. Since these milkweed butterflies also store cardenolides, other structural modifications of the Na⁺, K⁺-ATPase may have occurred or other strategies of cardenolide tolerance have been developed. Received 15 May 2000; accepted 29 June 2000     

干旱指标及其在新疆阿勒泰地区干旱监测分析中的应用

干旱是限制新疆阿勒泰地区农牧业生产可持续发展最主要的自然灾害之一,研究适合该区的干旱指标,是进行有效干旱监测的基础。采用新疆阿勒泰地区7个气象站1961-2008年4-10月月平均气温、降水量资料,首先通过Thomthwaite方法计算潜在蒸发量确定K干旱指数,然后对R指数、Z指数、K指数3种干旱指标进行了分析,结果表明,在监测诊断干旱轻重程度上,K指数能较客观地反映出干旱程度,R指数和Z指数监测干旱程度较轻。在此基础上,基于K指数建立的阿勒泰地区干旱监测评价的强度指数和面积指数,对该地区近48年来干旱的变化进行了分析,表明该地区干旱灾害主要集中在春夏季节,春夏连旱几率较高,强度较大;该地区干旱灾害具有阶段性特征,近年来干旱发生的频次有增多的趋势,其中秋季干旱相对较为明显。     

Cs and K in fruiting bodies of different fungal species collected in a single forest in southern Poland

Fruiting bodies of fungi belonging to more than 70 species were collected within a few thousand square meter area of one forest during 2006 and 2007. The soil profile was collected to check the cumulative deposition of ¹³⁷Cs, which was relatively high, equal to 64 ± 2 kBq/m² (calculated for October 2006). The majority of this activity was in the first 6 cm. Fruitbodies were analyzed for radiocesium and ⁴⁰K by means of gamma-spectrometry. The highest ¹³⁷Cs activity was 54.1 ± 0.7 kBq/kg (dry weight) for a sample of Lactarius helvus collected in 2006. The results for 2006 were higher than those for 2007. In a few cases the traces of short-lived (T_1/2 = 2.06 a) ¹³⁴Cs were still found in samples. The importance of mycorrhizal fungi for radiocesium accumulation is confirmed. The differences in activity among the species are discussed in relation to observations and predictions from previous studies, where the change in relative accumulation between fruiting bodies of different species was at least partially explained by the differences in the depth of the mycelium localization in a litter/soil system. It is concluded that in some cases, such as Boletus edulis and Xerocomus badius, this prediction is fulfilled and therefore this explanation confirmed.     

对影响高锰酸盐指数测定的重要因子--K值的探讨

高锰酸盐指数是水质监测中常规项目 ,在实际测定中 ,K值的大小直接影响测定过程。本文对K值进行讨论 ,并提出解决办法     

An innovative modeling approach using Qual2K and HEC-RAS integration to assess the impact of tidal effect on River Water quality simulation

Water quality modeling has been shown to be a useful tool in strategic water quality management. The present study combines the Qual2K model with the HEC-RAS model to assess the water quality of a tidal river in northern Taiwan. The contaminant loadings of biochemical oxygen demand (BOD), ammonia nitrogen (NH₃-N), total phosphorus (TP), and sediment oxygen demand (SOD) are utilized in the Qual2K simulation. The HEC-RAS model is used to: (i) estimate the hydraulic constants for atmospheric re-aeration constant calculation; and (ii) calculate the water level profile variation to account for concentration changes as a result of tidal effect. The results show that HEC-RAS-assisted Qual2K simulations taking tidal effect into consideration produce water quality indices that, in general, agree with the monitoring data of the river. Comparisons of simulations with different combinations of contaminant loadings demonstrate that BOD is the most import contaminant. Streeter-Phelps simulation (in combination with HEC-RAS) is also performed for comparison, and the results show excellent agreement with the observed data. This paper is the first report of the innovative use of a combination of the HEC-RAS model and the Qual2K model (or Streeter-Phelps equation) to simulate water quality in a tidal river. The combination is shown to provide an alternative for water quality simulation of a tidal river when available dynamic-monitoring data are insufficient to assess the tidal effect of the river.