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981.
为了探讨纳米银对HepG2细胞DNA损伤、染色体畸变等遗传毒性指标的影响,以期为纳米银体外遗传毒性评价提供参考依据,本文采用2种纳米银材料(20 nm-PVP包被纳米银、20 nm-无包被纳米银),分别以20μg·mL~(-1)、40μg·mL~(-1)、80μg·mL~(-1)、160μg·mL~(-1)的剂量对HepG2细胞染毒24 h,用Hoechst-33258染色法检测细胞凋亡,彗星实验检测DNA损伤,胞质分裂阻滞微核细胞组学试验法检测染色体畸变。结果表明,20 nm Ag NPs组在160μg·mL~(-1)时引起细胞凋亡数显著增多(P0.05);20 nm PVP-Ag NPs组在80μg·mL~(-1)和160μg·mL~(-1)剂量组中细胞凋亡数显著增多(P0.01)。2种纳米银引起HepG2细胞发生细胞凋亡,并呈剂量效应关系。彗星试验结果表明,20 nm Ag NPs和20 nm PVP-Ag NPs在40μg·mL~(-1)、80μg·mL~(-1)、160μg·mL~(-1)剂量组中,Olive尾矩、尾长和尾部DNA百分比与空白对照组相比均有显著差异(P0.05)。2种纳米银对HepG2细胞DNA损伤程度为:20 nm Ag NPs20 nm PVP-Ag NPs。胞质分裂阻滞微核细胞组学试验结果表明,2种纳米银均不会引起核质桥数发生明显改变(P0.05),20 nm Ag NPs在高染毒剂量下引起微核总数、I型微核、II型微核、核芽数明显升高(P0.05);20 nm PVP-Ag NPs在各染毒剂量下均会引起微核总数及I型微核数量升高(P0.01),II型微核数在160μg·mL~(-1)剂量下升高明显(P0.01),剂量大于20μg·mL~(-1)时核芽数升高(P0.01)。20 nm PVP-Ag NPs对细胞核的影响大于20 nm Ag NPs(P0.05)。总之,2种纳米银材料均会引起HepG2细胞DNA损伤及染色体畸变等遗传毒性效应的改变,无包被纳米银比PVP包被纳米银更容易引起DNA损伤,PVP包被纳米银比无包被纳米银更容易引起细胞染色体畸变相关效应;2种材料对HepG2细胞的损伤存在浓度-效应关系,浓度越高遗传毒性损伤越严重。 相似文献
982.
983.
我国10城市冬季大气颗粒物中多环芳烃污染及呼吸暴露风险评价 总被引:2,自引:0,他引:2
大气中颗粒物和多环芳烃对环境与人体健康危害较大,已引起社会各界的广泛关注。以我国10个城市2013年12月和2014年1月大气中空气动力学直径小于10μm的颗粒物(PM10)为研究对象,采用硅胶-氧化铝层析柱净化分离、气质联用仪分析的方法测定了27种多环芳烃(PAHs)的浓度水平,分析其谱分布及空间分布,并通过呼吸暴露途径估算了癌症病发增量(ILCRs)和人群归因危险度百分比(PAF)。结果表明,27种物质的总浓度为13.72~2 002 ng·m-3;在10个城市中晋中总浓度最高,厦门最低。PAHs空间污染水平呈现北方高于南方、东部沿海城市浓度相对较低的趋势。温度与总浓度有相关性。在27种PAHs中,占主导地位的单体为荧蒽(FLA,7.56%~19.8%),芘(PYR,6.72%~13.8%),艹屈(CHR,12.8%~19.6%)和苯并(k)荧蒽(Bk F,8.59%~15.5%),4者占到多环芳烃总浓度的42.1%~64.3%。根据研究区域苯并[a]芘(Ba P)人口加权浓度估算ILCRs范围为8.94×10-6~4.77×10-4,据此计算的PAFs为0.487%~13.2%,均值为3.44%,高于全国平均水平1.6%。上述研究结果为大气颗粒物中PAHs的研究提供重要的数据基础。 相似文献
984.
985.
Chemical speciation and phytoavailability of Zn, Cu, Ni and Cd in soil amended with fly ash-stabilized sewage sludge 总被引:7,自引:0,他引:7
A sequential extraction method was used to determine chemical forms of Cu, Zn, Ni and Cd in fly ash-stabilized sludge. A loamy acid soil amended with fly ash-stabilized sludge was used to grow corn under greenhouse conditions. Sewage sludge amended with coal fly ash can reduce the availability of Cu, Zn, Ni and Cd in the sludge. Increasing fly ash amendment rate significantly reduced DTPA-extractable Cu, Zn, Ni and Cd concentrations. Percentages of Cu, Zn and Ni in residual fraction increased with an increase in fly ash amendment rates. Majority of Cu was associated with organic form, but Zn and Ni were associated with Fe-Mn oxide and residual forms. Addition of ash-amended sludge to soil significantly increased dry mass of corn. With coal fly ash amendment rate increasing, concentrations of Zn and Cu in shoot tissues of corn decreased significantly, but concentrations of Cd and Ni did not change significantly. Significant correlations were found between concentrations of Cu and Zn in corn shoot and oxide and total Cu fractions, and all chemical fractions of Zn in fly ash-stabilized sludge, respectively. Hence, ash amendment significantly reduced the availability of heavy metals by chemical modification of their chemical speciation into less available forms. 相似文献
986.
Toxicity evaluation of sewage sludges in Hong Kong. 总被引:14,自引:0,他引:14
Anaerobically digested sewage sludges collected from four wastewater treatment plants located in Sha Tin, Tai Po, Yuen Long, and Shek Wu Hui in Hong Kong were subjected to chemical characterization and toxicity testing to provide preliminary assessment of their suitability for land application. All sewage sludges were slightly alkaline with pH range of 8.3-8.7. Electrical conductivity (EC; 0.69 dS m(-1)) and soluble NH4-N content (996 mg kg(-1)) of sewage sludge from Yuen Long were lower than that of other plants. Concentrations of heavy metals were determined as total, extractable, and water-soluble fraction using mixed acid digestion, DTPA (pH 7.3), and distilled water, respectively. Yuen Long sludge was most polluted with Zn and Cr higher than the pollutant concentration limits listed in Part 503 of USEPA, owing to the effluent coming from the tannery industry. High concentration of Ni was found in sludge from Sha Tin that originated mainly from the electroplating industry. DTPA-extractable Zn contents were high in sludges from Yuen Long (1247 mg kg(-1)) and Shek Wu Hui (892 mg kg(-1)), while 3.7 mg kg(-1) of DTPA-extractable Cr was found in Yuen Long sludge. Metal speciation of sludges showed that Pb was major in residual phase while Cu, Cr, and Ni in organic and residual phases, and Zn did not show any dominant chemical phase. The sludge extracts did not exert significant adverse effect on seed germination of Brassica chinensis (Chinese cabbage), but Yuen Long sludge caused a reduction in root growth. In view of its lower EC and soluble ammonia contents, the high concentration of Zn and Cr in Yuen Long sludge would likely be responsible for this adverse effect on root growth. Therefore, Yuen Long sludge would likely have a more serious impact on soil quality and plant growth as compared to other sludges. This would require further verification from greenhouse and field experiments. 相似文献
987.
Ecosystem management based on ecosystem services and human activities: a case study in the Yanhe watershed 总被引:3,自引:0,他引:3
Changhong Su Bojie Fu Yongping Wei Yihe Lü Guohua Liu Daolong Wang Kebiao Mao Xiaoming Feng 《Sustainability Science》2012,7(1):17-32
With activities that alter the structure and function of the habitat, humans have a direct impact on ecosystems and ecosystem
services, i.e., the conditions and processes that sustain human life. In this study, 35 townships in the Yanhe watershed in
the Loess Plateau of China were selected. The net primary production (NPP), carbon sequestration and oxygen production (CSOP),
water conservation, and soil conservation were the ecosystem services selected and valuated. Human activity was quantified
by an integrated human activity index (HAI) based on population density, farmland ratio, and the influence of road networks
and residential areas. The NPP, CSOP, and water conservation showed a conspicuous spatial pattern fanning outward from the
southwest, while the soil conservation showed an obscure spatial pattern distinguished primarily by the peripheral area surrounding
the urbanized areas. Total ecosystem services in the Yanhe watershed demonstrated a decreasing pattern from south to north,
and the HAI was in proportion to administrative and economic development. Based on the selected ecosystem services and HAI,
we mapped the townships of the Yanhe watershed by cluster analysis, and provided sustainable ecosystem management suggestions,
tailored to the social-ecological map. 相似文献
988.
利用安徽省78个气象台站1971~2010年能见度和相对湿度资料,统计出历年各站霾发生日数并分析其时空分布特征,通过历年霾日数变化趋势、EOF分析等方法对安徽省近40 a霾的气候变化特征进行分析。结果表明:安徽省霾日数存在显著的增多趋势;霾高发期在秋冬季,1月更是一年中霾发生最多的月份;5~6月是霾发生的次高峰,6月的极重霾为全年中最多;白天出现霾的几率高于夜晚,早上8时是一天中最容易出现霾的时刻。安徽省霾年平均日数的空间分布很不均匀,平原多于山区,主要城市及周边地区的年平均霾日数较多,山区很少;沿淮淮北的极重霾日数最多。2007年前后霾的年平均日数达到40 a来的最高值。霾日数EOF前4个模态累积方差贡献为793%,说明安徽省绝大部分地区霾日数随年代的变化都是呈增长趋势;时间系数表现为明显的年代变化,以3~4 a周期震荡增长为主 相似文献
989.
This study describes spatial and temporal patterns of variability in population parameters in the barnacle Chthamalus montagui Southward in three localities of northern Spain and evaluates whether density-dependent settlement may regulate population
dynamics. The sampling design considered two spatial scales, localities and sites within localities, and two temporal scales,
years and six month intervals. Density, amount of free space, mortality, growth rate and magnitude of settlement (both absolute
and per unit of free space) were obtained from photographs of permanent quadrats and from direct counts in the field. The
number of settlers in scraped and untouched quadrats was used to estimate the importance of the presence of conspecifics in
settlement. Significant variation at the two spatial and temporal scales was found for most parameters. Large spatial and
temporal variations in adult mortality rate, density, and settlement were observed. Patterns of mortality were not consistent
with differences in density among localities. Differences in settlement among localities were maintained through time. We
suggest that magnitude of settlement is regulated by persistent features such as topography or local water circulation. We
assume that early post-settlement mortality does not differ among localities. In the absence of differential mortality, settlement
determines average population density within localities. Within localities, settlement was independent of density and free
space. No consistent evidence was found on preferential settlement at the vicinity of conspecifics. The main conclusion is
that density-dependent settlement is not relevant for the regulation of the populations of C. montagui in the northern Spain. Regulation might occur by density-dependent processes within the adult fraction of the population
and/or the larval phase before settlement. 相似文献
990.
藻红外辐射测试环境重金属急性毒性 总被引:4,自引:0,他引:4
快速、简便、有效地检测环境中重金属毒性是环境保护的一项重要内容.敏感藻是指藻红外测试中对毒物响应的温差大、种类多、时间快、剂量低的特殊藻类,为探寻对重金属急性毒性响应的敏感藻,2006年5月至2007年10月,进行了8种藻对10种重金属的温度响应测试试验.结果表明:平均响应温差短线脆杆藻(Fragilaria brevistriata)最大,为0.24 ℃,高出8种藻的0.19 ℃总平均温差0.05 ℃;较好药品响应率短线脆杆藻最高,为80%;平均响应时间短线脆杆藻居中,为4.65 min,低于8种藻的总平均响应时间5.21 min;短线脆杆藻对重金属的灵敏度在0.06~7.0 mg?L-1之间,发光细菌在0.07~15.3 mg?L-1之间,表明短线脆杆藻对重金属响应的剂量低.根据敏感藻的定义和分析结果,确定短线脆杆藻为本试验的敏感藻. 相似文献