Mycobiota and mycotoxins in bee pollen collected from different areas of Slovakia

Contamination by microscopic fungi and mycotoxins in different bee pollen samples, which were stored under three different ways of storing as freezing, drying and UV radiation, was investigated. During spring 2009, 45 samples of bee-collected pollen were gathered from beekeepers who placed their bee colonies on monocultures of sunflower, rape and poppy fields within their flying distance. Bee pollen was collected from bees’ legs by special devices placed at the entrance to hives. Samples were examined for the concentration and identification of microscopic fungi able to grow on Malt and Czapek-Dox agar and mycotoxins content [deoxynivalenol (DON), T-2 toxin (T-2), zearalenone (ZON) and total aflatoxins (AFL), fumonisins (FUM), ochratoxins (OTA)] by direct competitive enzyme-linked immunosorbent assays (ELISA). The total number of microscopic fungi in this study ranged from 2.98 ± 0.02 in frozen sunflower bee pollen to 4.06 ± 0.10 log cfu.g^?1 in sunflower bee pollen after UV radiation. In this study, 449 isolates belonging to 21 fungal species representing 9 genera were found in 45 samples of bee pollen. The total isolates were detected in frozen poppy pollen 29, rape pollen 40, sunflower pollen 80, in dried poppy pollen 12, rape pollen 36, sunflower 78, in poppy pollen after UV radiation treatment 54, rape 59 and sunflower 58. The most frequent isolates of microscopic fungi found in bee pollen samples of all prevalent species were Mucor mucedo (49 isolates), Alternaria alternata (40 isolates), Mucor hiemalis (40 isolates), Aspergillus fumigatus (33 isolates) and Cladosporium cladosporioides (31 isolates). The most frequently found isolates were detected in sunflower bee pollen frozen (80 isolates) and the lowest number of isolates was observed in poppy bee pollen dried (12 isolates). The most prevalent mycotoxin of poppy bee pollen was ZON (361.55 ± 0.26 μg.kg^?1), in rape bee pollen T-2 toxin (265.40 ± 0.18 μg.kg^?1) and in sunflower bee pollen T-2 toxin (364.72 ± 0.13 μg.kg^?1) in all cases in frozen samples.     

Laboratory studies of dissipation of 14C‐DDT from soil and plywood surfaces

Abstract

The effects of temperature and solar radiation on dissipation of ¹⁴C‐p,p'‐DDT from a latosol soil were studied under laboratory conditions. Volatilization was measured by trapping organic volatiles during 6 weeks and was found to increase with rise of temperature from 3.8% of initial amount at ambient temperature to 5.9% at 45°C.

Studies on the effect of solar radiation using quartz tubes under sterilized and non‐sterilized conditions have shown that volatilized organics were highest in quartz tubes, with soil microflora presumably playing a very minor role in volatilization. Mineralization was shown to be low in sterilized systems and highest in non‐sterilized quartz systems. Studies on binding suggest that soil bioactivity may be involved in the formation of a portion of the bound residue. These laboratory experiments seem to support data from the field, where it is maintained that volatilization is a major mechanism for dissipation. Degradation in soil and to a lesser extent solar irradiation contribute also substantially to the dissipation mechanisms. Radiocarbon dissipated from plywood surfaces under indoor conditions in a biphasic fashion. Loss of 50% occurred after 5.5 weeks while the remainder dissipated at a very slow rate.     

Atrazine removal by ozonation processes in surface waters

Abstract

Atrazine (6‐chloro‐N‐ethyl‐N'‐isopropyl‐1,3,5‐triazinedyl‐2,4‐diamine) was treated with ozone alone and in combination with hydrogen peroxide or UV radiation in three surface waters. Experiments were carried out in two bubble reactors operated continously. Variables investigated were the ozone partial pressure, temperature, pH, mass flow ratio of oxidants fed: hydrogen peroxide and ozone and the type of oxidation including UV radiation alone. Residence time for the aqueous phase was kept at 10 min. Concentrations of some intermediates, including deethylatrazine, deisopropylatrazine and deethyldeisopropylatrazine, were also followed. The nature of water, specifically the alkalinity and pH were found to be important variables that affected atrazine (ATZ) removal. Surface waters with low alkalinity and high pH allowed the highest removal of ATZ to be reached. There was an optimum hydrogen peroxide to ozone mass flow ratio that resulted in the highest ATZ removal in each surface water treated. This optimum was above the theoretical stoichiometry of the process. Therefore, to reach the maximum removal of ATZ in a O₃/H₂O₂ process, more hydrogen peroxide was needed in the surface waters treated than in ultrapure water under similar experimental conditions. In some cases, UV radiation alone resulted in the removal of ATZ higher than ozonation alone. This was likely due to the alkalinity of the surface water. Ozonation and UV radiation processes yield different amounts of hydrogen peroxide. Combined ozonations (O₃/H₂O₂ and O₃/UV) lead to ATZ removals higher than single ozonation or UV radiation but the formation of intermediates was higher.     

微波辐照碳酸钾化学活化法制备菌渣活性炭

以食用菌渣为原料,以K2CO3为活化剂,利用微波辐照加热法制备活性炭。采用正交实验设计,研究了活化功率、活化时间、K2CO3与菌渣质量比、浸渍时间对活性炭碘值及得率的影响。实验结果表明,活化时间、活化功率、K2CO3与菌渣质量比对活性炭碘值影响显著,浸渍时间对活性炭碘值影响不显著;对活性炭得率,各因素影响均不显著。综合考虑碘值和得率2个指标,实验得出的最佳活性炭制备工艺条件为:活化功率560 W,活化时间20 min,K2CO3与菌渣质量比0.8,浸渍时间20 h。     

进口高效菌用于青藏铁路污水处理应急保障的可行性研究

青藏铁路沿线污水处理安全运营保障体系中,应急状态下需要大量的接种备用活性污泥。在实验室研究基础上,考察了进口高效菌低温低压条件下对污染物的处理能力,最后将其应用到拉萨污水处理厂实际工程。实验室研究及实际对比实验结果表明,高效菌在低温低压下的处理性能和青藏高原实际的活性污泥性能基本相当,如与微生物固定化技术结合使用,可大大增加强化生化处理的效果。进口高效菌具有微生物活性高、培养时间短、保存携带方便,能快速提升生化系统处理能力的优点,可满足青藏线污水处理设施应急状态下处理能力快速提升和安全稳定运行的需要。     

Phenogenetic response of silver birch populations and half-sib families to elevated ozone and ultraviolet-B radiation at juvenile age

Phenogenetic response of silver birch populations and half-sib families to separate and combined elevated ozone (O₃) concentrations and ultraviolet-B (UV-B) radiation dozes was studied at juvenile age in the climatic chambers. Significant population and family effects were found for seedling height, lamina width, and leaf damage. The exposure to UV-B radiation decreased genetic variation at the stage of seed germination. Complex exposure to UV-B and O₃ caused an increase of genetic variation at the stage of intensive seedling growth: seedling height genetic variation in separate treatments increased from 23.7–38.6 to 33.7–65.7%, the increase for lamina width was from 10.2–13.9 to 13.6–31.8%. Different populations and families demonstrated differing response to elevated complex UV-B and O₃ exposure. Changes of genetic intra-population variation were population-specific. Such changes in genetic variation under the impact of stressors can alter adaptation, stability, and competitive ability of regenerating populations in a hardly predictive way.     

输变电建设项目环境管理中存在问题及对策探讨

阐述了输变电建设项目在环境标准、技术规范、公众参与及竣工环保验收等方面存在的问题,并针对这些方面提出了建议。     

UV-B辐射增强对褶皱臂尾轮虫种群增殖的影响

运用群体累计培养的方法研究了UV-B辐射增强对褶皱臂尾轮虫(Brachionus plicatilis)种群增殖的影响.结果表明:UV-B辐射对褶皱臂尾轮虫的种群数量、雌体抱卵率和种群增殖率都有显著影响.在本实验辐射强度(20 μW/cm2)和剂量范围内,低剂量的0.24和0.48 kJ/m2 处理组在实验的一定时期内对褶皱臂尾轮虫的种群数量和雌体抱卵率有一定的刺激作用;而高剂量的0.72、0.96和1.20 kJ/m2 处理组对轮虫的种群数量和雌体抱卵率则有显著的抑制作用,甚至可导致整个种群的灭绝.褶皱臂尾轮虫的种群增殖率随UV-B辐射的增强显示出了一致性减小的变化规律,因此可以作为指示大气UV-B辐射强弱的生物指标.     

1983～2012年长江流域地表净辐射变化特征

本文采用统计相关分析、Morlet小波分析、Rodionov时间序列分析与GIS空间分析等技术方法,分析了1983年7月至2012年9月长江流域SRB和CERES地表净辐射月产品的时空变化特征.结果表明:拟合后遥感产品比气象辐射站点观测值整体高15.8％,平均误差为15.31 W/m2,均方根误差为21.58W/m2.长江流域地表净辐射多年均值为78.0W/m2,整体呈下降趋势,于1996年突降,存在16年和10年周期;季相上,呈夏＞春＞秋＞冬.空间上,呈现西部地区＞东部地区＞中部地区;1996～2012年相较1983～1995年净辐射整体下降,其中上游流域降幅大于中下游;净辐射降低主要出现在5～7月,降幅较大地区主要是长江上游流域部分地区和长江中游流域纬度较低地区.研究结果对于认识长江流域的气候变化条件下的能量和水分循环过程等具有重要意义.     

贵阳地铁1号线氡浓度特征及其潜在健康效应评估

地铁轨道交通逐渐成为人们日常出行的首选,但作为较封闭的地下空间环境易导致氡积聚,对于工作人员和乘客存在潜在的电离辐射暴露风险,有必要进行监测评估。贵阳地铁1号线于2018年12月开通运营,所穿越地层主要为碳酸盐岩,该地层风化过程中常常产生氡异常,尤需引起关注。本研究利用RAD-7电子测氡仪,分别于2020年7月29日和2021年1月7日对该地铁全线20个地下站点及车厢中空气氡浓度进行监测,分析其时空变化特征及主要影响因素,估算人员暴露剂量,评估潜在健康效应。结果表明：贵阳地铁1号线氡浓度水平为9.6～257.5 Bq/m³,均值为38.9 Bq/m³,高于我国主要城市地铁氡平均值(28.9 Bq/m³),低于国外平均值(105.2 Bq/m³);且不同站点存在较大差异,整体上氡浓度夏季低于冬季。计算发现,站内工作人员因氡及其子体暴露导致的有效剂量为0.28 mSv/a,小于天然背景辐射值(约为2.4 mSv/a),属于低剂量辐射范围,不存在健康风险。