电化学法检测芴的细胞毒性

以小鼠胚胎成纤维细胞(BALB/c 3T3)和中国仓鼠肺细胞(V79)为模型细胞,利用基于石墨烯量子点/玻碳电极(RGOQDs/GCE)的细胞电化学法研究多环芳烃(PAHs)类化合物芴的细胞毒性,并与四唑盐比色试验(MTT)对比,验证电化学法的可靠性.时间-效应研究结果表明,培养时间为30 h时,芴对2种细胞的毒性最强;剂量-效应研究结果表明,电化学法测得的芴对BALB/c 3T3和V79细胞毒性的半数抑制浓度(IC50)值分别为0.89 mmol·L-1和0.25 mmol·L-1,MTT法测得的IC50值分别为1.34 mmol·L-1和0.86 mmol·L-1.这说明芴对V79细胞的毒性效应更强,这可能是由于芴对V79细胞嘌呤核苷酸代谢影响更大.电化学法的检测结果与MTT法的结果趋势一致,且IC50值均低于MTT法,说明本文使用的电化学法可以有效灵敏地评价芴的细胞毒性.芴的细胞毒性作用机制可能是通过激活细胞中p53基因进而影响细胞嘌呤核苷酸代谢.本法通过检测细胞中嘌呤含量变化而评价芴的细胞毒性.     

Understand the local and regional contributions on air pollution from the view of human health impacts

• PM_2.5-related deaths were estimated to be 227 thousand in BTH & surrounding regions. • Local emissions contribute more to PM_2.5-related deaths than PM_2.5 concentration. • Local controls are underestimated if only considering its impacts on concentrations. • Rural residents suffer larger impacts of regional transport than urban residents. • Reducing regional transport benefits in mitigating environmental inequality. The source-receptor matrix of PM_2.5 concentration from local and regional sources in the Beijing-Tianjin-Hebei (BTH) and surrounding provinces has been created in previous studies. However, because the spatial distribution of concentration does not necessarily match with that of the population, such concentration-based source-receptor matrix may not fully reflect the importance of pollutant control effectiveness in reducing the PM_2.5-related health impacts. To demonstrate that, we study the source-receptor matrix of the PM_2.5-related deaths instead, with inclusion of the spatial correlations between the concentrations and the population. The advanced source apportionment numerical model combined with the integrated exposure–response functions is used for BTH and surrounding regions in 2017. We observed that the relative contribution to PM_2.5-related deaths of local emissions was 0.75% to 20.77% larger than that of PM_2.5 concentrations. Such results address the importance of local emissions control for reducing health impacts of PM_2.5 particularly for local residents. Contribution of regional transport to PM_2.5-related deaths in rural area was 22% larger than that in urban area due to the spatial pattern of regional transport which was more related to the rural population. This resulted in an environmental inequality in the sense that people staying in rural area with access to less educational resources are subjected to higher impacts from regional transport as compared with their more resourceful and knowledgeable urban compatriots. An unexpected benefit from the multi-regional joint controls is suggested for its effectiveness in reducing the regional transport of PM_2.5 pollution thus mitigating the associated environmental inequality.     

Contamination levels and human health risk assessment of toxic heavy metals in street dust in an industrial city in Northwest China

This study investigated the content, distribution, and contamination levels of toxic metals (Cd, Cr, Cu, Pb, and Zn) in street dust in Lanzhou, an industrial city in Northwest China. Meanwhile, the risk these metals posed to the urban ecosystem and human health was also evaluated using the potential ecological risk index and human exposure model. Results showed that concentrations of these metals in the dust are higher than the background value of local soil, with Cu having the highest levels. The districts of Anning and Xigu had the most extreme levels of contamination, while Chengguan and Qilihe districts were lightly contaminated, which can be partly attributed to human activities and traffic densities. In comparison with the concentrations of selected metals in other cities, the concentrations of heavy metals in Lanzhou were generally at moderate or low levels. Heavy metal concentration increased with decreasing dust particle size. The pollution indices of Cr, Cd, Cu, Pb, and Zn were in the range of 0.289–2.09, 0.332–2.15, 1.38–6.21, 0.358–2.59, and 0.560–1.83 with a mean of 1.37, 1.49, 3.18, 1.48, and 0.897, respectively. The geo-accumulation index (I _geo) suggested that Zn in street dust was of geologic origin, while Cd, Cr, Pb, and Cu were significantly impacted by anthropogenic sources. The comprehensive pollution index showed that urban dust poses a high potential ecological risk in Lanzhou. Non-carcinogenic and carcinogenic effects due to exposure to urban street dust were assessed for both children and adults. For non-carcinogenic effects, ingestion appeared to be the main route of exposure to dust particles and thus posed a higher health risk to both children and adults for all metals, followed by dermal contact. Hazard index values for all studied metals were lower than the safe level of 1, and Cr exhibited the highest risk value (0.249) for children, suggesting that the overall risk from exposure to multiple metals in dust is low. The carcinogenic risk for Cd and Cr was all below the acceptable level (< 10⁻⁶).

     

Effects of a lead- and cadmium-resistant fungal strain on the absorption of heavy metals by Vetiveria zizanioides北大核心CSCD

A two-factor randomized complete block experiment was used to explore the remediation by a plant-microorganism combination on soils contaminated by lead (Pb) and cadmium (Cd). Factor A was the amount of fungi, for which four values were considered, namely, 0, 1, 3, and 5 g. Factor B was the level of contamination by lead and cadmium, for which six values were considered, namely, Cd0Pb0, Cd10Pb400, Cd20Pb600, Cd30Pb800, Cd50Pb1200, and Cd80Pb1800 (data in units of mg/ kg). The results showed that the resistant fungi promoted the growth of vetiver (Vetiveria zizanioides). At weights of 1, 3, and 5 g, the resistant fungi increased the biomass of vetiver by 41.9%, 74.9%, and 71.7% respectively. The resistant fungi stimulated the absorption of lead and cadmium by both the aerial and underground parts of vetiver. In the presence of 80 mg/kg of Cd2+ and 1 800 mg/kg of Pb2+, the contents of lead in the aerial parts of vetiver were increased by 120.6%, 265.4%, and 242.9%, while the lead content in the underground parts were increased by 110.3%, 278.2%, and 266.2%, after the addition of 1 g, 3 g, and 5 g of fungi, respectively. The content of cadmium in the aerial parts increased by 113.2%, 238.3%, and 217.3%, while the content of cadmium in the underground parts increased by 103.1%, 298.8%, and 274.4%, after the addition of 1 g, 3 g, and 5 g of fungi, respectively. The addition of fungi strengthened the effect of V. zizanioides to remediate soils contaminated by lead and cadmium, and the remediation after the addition of 3 g of fungi was better than that after treatment with 1 g and 5 g of fungi. The combination of resistant fungi and the heavy metal enrichment plant, vetiver, under different concentrations of lead and cadmium showed that the fungi had a significant effect on the remediation of soils contaminated by lead and cadmium. © 2018 Science Press. All rights reserved.     

Air pollution-oriented ecological risk assessment in Xiamen city,China

Urban energy consumption is one of the most important causes of air pollution. Air pollution-oriented ecological risk assessment is of great significance to the promotion of urban environmental protection. This paper focuses on ecological risk in Xiamen city caused by air pollutant discharge from urban energy consumption. The Long-range Energy Alternatives Planning model was used to establish two scenarios of energy consumption in Xiamen city, and based on different scenarios, we estimated urban energy consumption and discharge quantity of air pollutant (DQAP). A box model and an expert scoring method were used to calculate the air pollution burden (APB) of SO₂, NO₂, CO, PM₁₀ and PM_2.5 and to obtain the probabilities of different air pollution loads. An ecological risk assessment model was developed and utilized to predict Xiamen city’s ecological risks in 2020. The results showed that under an energy-saving scenario, the ecological risks for PM_2.5, SO₂ and NO₂ are high, whereas the ecological risks for CO and PM₁₀ are low. Under a baseline scenario, the ecological risks for PM_2.5, SO₂ and NO₂ are moderate, whereas the ecological risks for CO and PM₁₀ are low. In addition, the APB of SO₂, NO₂, CO, and PM_2.5, but not of PM₁₀, is predicted to rise. In the simulation, energy generation from coal is the main source of air pollution. Although the DQAP from automobiles is not high, it is predicted to rise year-on-year. In summary, the ecological risk due to pollution in Xiamen city is high, and the main pollutants are SO₂, NO₂ and PM_2.5.     

丙烯腈诱导的氧化应激对大鼠肝脏内质网应激信号通路的影响

为探讨丙烯腈(acrylonitrile,ACN)诱导的大鼠肝脏氧化损伤对内质网应激(endoplasmic reticulum stress,ERS)信号通路的影响,我们将50只SPF级成年雄性SD大鼠按体重随机分为5组,每组10只。各组分别以12.5、25.0、50.0 mg·kg~(-1)ACN灌胃染毒,N-乙酰半胱氨酸(N-acetylcysteine,NAC)干预组先用300.0 mg·kg~(-1)NAC灌胃30 min后再灌50.0 mg·kg~(-1)ACN,对照组以0.5 mL·(100 g)~(-1)的玉米油灌胃,1次·天~(-1),6天·周~(-1),共计13周。染毒结束后,检测肝脏组织氧化还原酶活力及丙二醛(malondialdehyde,MDA)含量,GRP78、CHOP及caspase-12 mRNA及蛋白表达水平。结果显示:低、中ACN组大鼠肝脏GSH含量显著低于对照组(P0.05);低ACN组大鼠肝脏GSH-Px活力、SOD活力及MDA含量均显著高于对照组(P0.05);中、高ACN组大鼠肝脏CAT活力明显低于对照组(P0.05)。NAC干预后可逆转ACN诱导的大鼠肝脏GSH含量、MDA含量及SOD活力的变化。RT-PCR结果显示,高ACN组大鼠肝脏GRP78、CHOP、caspase-12 mRNA表达水平与对照组比较均升高(P0.05)。NAC干预后,CHOP、caspase-12 mRNA表达水平与高ACN组比较均降低(P0.05)。Western Blot结果显示,高ACN组大鼠肝脏GRP78、CHOP、caspase-12蛋白表达水平与对照组比较均升高(P0.05),NAC干预后可逆转以上作用。结果表明,ACN慢性染毒对大鼠肝脏的氧化损伤可激活ERS信号通路,NAC可减轻氧化损伤的程度而阻断ERS信号通路,这可能是ACN产生肝脏毒性的机制之一。     

纳米金属氧化物对土壤酶活性的影响研究进展

纳米金属氧化物的大量生产和广泛应用使其不可避免地进入环境中,土壤是其释放到环境中主要的汇。纳米颗粒由于尺寸效应,具有许多独特的物理化学性质,其进入环境后潜在的生态和健康风险问题日益受到研究者的关注。土壤酶是土壤生物化学过程的主要参与者,也是生态系统物质循环和能量流动过程中最活跃的生物活性物质。土壤酶活性的变化能反映土壤中生化反应的情况,可作为评价土壤中纳米材料污染状况的生物学指标。本文较系统地回顾和总结了纳米金属氧化物对土壤酶活性的影响及可能的影响途径,探讨了纳米金属氧化物作用于土壤酶的主要影响途径,并展望了未来研究主要发展方向。     

草甘膦对非靶标生物的毒性研究进展

随着现代农业的飞速发展,农药的使用越来越广泛。草甘膦作为全球销量最大的农药除草剂,在自然环境中广泛存在,其对生态环境和人类健康的影响越来越受到人们的关注。文中从水生/两栖动物、土壤生物、哺乳动物以及人群等4个方面对除草剂草甘膦对非靶标生物的毒性研究概况进行综述,并对该领域未来发展趋势做了简要分析与展望,以期为草甘膦的生态安全和环境风险评价提供数据资料,为其合理使用提供理论指导。     

考虑典型密集建筑群影响的爆炸超压空间分布规律分析

爆炸已逐渐成为影响人们生活的典型灾害,一旦在建筑密集的城市环境中发生爆炸事故,相应灾后评估工作是十分重要的,而爆炸灾害评估与爆炸超压空间分布密切相关。提出了一种与空间分布相关的爆炸灾害评估方法,明确考虑建筑群影响的爆炸波传播机制及其影响因素分析,研究爆炸波能量衰减规律以及具有时变特点的超压空间分布规律,确定与破坏程度密切相关的3种典型超压影响范围。根据超压影响范围对单体建筑物以及密集建筑群中同一建筑物进行分区,确定3种区域的等压线位置,界定爆炸的影响范围。利用LS-DYNA软件进行模拟分析,分别建立炸药在刚性地面上单体建筑物及密集建筑群爆炸响应有限元分析模型,绘制建筑物上的等压曲线,得出影响建筑物上超压分布的主要因素主要为比例距离和建筑群密集程度。