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541.
Robson R. M. Barizon Ricardo de Oliveira Figueiredo Débora Renata Cassoli de Souza Dutra Jussara Borges Regitano Vera Lúcia Ferracini 《Journal of environmental science and health. Part. B》2020,55(3):283-292
AbstractCamanducaia River is part of the Piracicaba watershed responsible for pumping water into the Cantareira System, which is one of the main water sources for the metropolis of São Paulo and Campinas, Brazil. Intensive use of pesticides and hilly topography represents a situation of high risk for river water contamination. Therefore, water samples from 12 locations were collected along the Camanducaia River and its tributaries, over a period of 4?mo during the rainy season, and analyzed by GC-MS/MS or UPLC- MS/MS for the presence of 46 pesticides. Seven pesticides (fipronil, methyl parathion, metolachlor, atrazine, carbofuran, diuron, and simazine) were positively detected. Only atrazine (the most frequently detected) and diuron were present at concentrations above the limit of quantification of the analytical method (0.32 and 0.57?μg L?1 for atrazine and diuron, respectively). Pesticides detection frequency was higher than expected for a river system where only 11.8% of the land area is under agriculture. The vulnerability of the Camanducaia basin to pesticide contamination is attributed to the high annual precipitation (> 1.5?m y?1 in the headwaters), associated with topographical features (steep terrain) and soil types that favor surface runoff, which has been exacerbated by poor soil management practices. 相似文献
542.
气相色谱法测定糙米中水胺硫磷和甲基异柳磷的残留量 总被引:3,自引:0,他引:3
本文用带氮磷检测器的气相色谱仪,测定糙米中水胺硫磷和甲基异柳磷残留量,结果表明:水胺硫磷和甲基异柳磷最小检出量分别为1.3×10~(-11)g和2.8×10~(-12)g,最低检出浓度分别为0.7ppb和0.1ppb,回收率添加浓度为0.05—5mg/kg时,回收率范围分别为89.9—97.8%和100.7—104.9%,变异系数绝对值分别为3.42—5.58%和1.33—2.36%。 相似文献
543.
544.
Freddie-Jeanne Richard Michael Poulsen Abraham Hefetz Christine Errard David R. Nash Jacobus J. Boomsma 《Behavioral ecology and sociobiology》2007,61(11):1637-1649
Cuticular hydrocarbon profiles are essential for nestmate recognition in insect societies, and quantitative variation in these
recognition cues is both environmentally and genetically determined. Environmental cues are normally derived from food or
nest material, but an exceptional situation may exist in the fungus-growing ants where the symbiotic fungus garden may be
an independent source of recognition compounds. To investigate this hypothesis, we quantified the chemical profiles of the
fungal symbionts of 18 sympatric colonies of Acromyrmex echinatior and Acromyrmex octospinosus and evaluated the quantitative variation of the 47 compounds in a multivariate analysis. Colony-specific chemical profiles
of fungal symbionts were highly distinct and significantly different between the two ant species. We also estimated the relative
genetic distances between the fungal symbionts using amplified fragment length polymorphism (AFLP) and correlated these with
the overall (Mahalanobis) chemical distances between the colony-specific profiles. Despite the standardized laboratory conditions,
the correlations were generally weak, but a statistically significant portion of the total variation in chemical profiles
could be explained by genetic differences between the fungal symbionts. However, there was no significant effect of ant species
in partial analyses because genetic differences between symbionts tend to coincide with being reared by different ant species.
However, compound groups differed significantly with amides, aldehydes, and methyl esters contributing to the correlations,
but acetates, alkanes, and formates being unrelated to genetic variation among symbionts. We show experimentally that workers
that are previously exposed to and fed with the fungal symbiont of another colony are met with less aggression when they are
later introduced into that colony. It appears, therefore, that fungus gardens are an independent and significant source of
chemical compounds, potentially contributing a richer and more abundant blend of recognition cues to the colony “gestalt”
than the innate chemical profile of the ants alone.
Freddie-Jeanne Richard and Michael Poulsen contributed equally to this work. 相似文献
545.
贵州百花湖水中溶解有机质的分子量分布随深度的变化规律 总被引:1,自引:0,他引:1
利用高效体积排阻色谱法测量了百花湖水中溶解有机质的分子量及其分布。结果表明百花湖水中溶解有机质(DOM)主要以分子量小于3500道尔顿(Da)的组分为主,其中重均(Mw)和数均(Mn)分子量分别界于2300~2500 Da和1900~2150 Da之间,说明其主要来源于降水对土壤有机物的淋滤和径流作用。根据色谱分析的结果,可以把溶解有机质的分子量分布分为四个组分:大分子量组分(MW〉3500 Da);中等偏大分子量组分(3500~2000 Da);中等分子量组分(2000~1000 Da)和小分子量组分(MW〈1000 Da)。由于生物活动和光降解作用以及有机物的分解作用,导致各分子量组分随深度的变化规律不同,其中分子量在3500~2000 Da之间的有机物的含量随深度的增大而增大,其余组分的含量随深度的增大而减少。计算所得的溶解有机质的Mw和Mn在表层较小,在中部随深度基本保持不变,到底部又变大。这种变化趋势与分子量组分的变化结果一致。 相似文献
546.
547.
利用气相色谱-电子捕获检测器法(GC-ECD)测量大气中氧化亚氮(N_2O)浓度是目前广泛使用的方法,但ECD分析N_2O时存在线性范围较窄的缺点,因此,标气数量和定量方式是决定分析结果的关键因素.基于此,本文对比分析了单点线性校正法(S)、多点线性拟合法(D)、单瓶标气近似校正法(SA)、单瓶标气比值校正法(SC)对N_2O检测分析结果的差异.结果表明,SA定量相对误差最小,对测试使用的6瓶标气定值平均误差为0.09×10~(-9).根据本底大气N_2O观测精度要求,以及我国大气N_2O浓度变化范围较大的特征,推荐选用SA法对大气中N_2O浓度进行定值.依据所选方法对黑龙江龙凤山本底站大气N_2O浓度进行观测(2015年1—12月),结果显示,黑龙江龙凤山站大气N_2O浓度最高值出现在4—5月,平均值超过330×10~(-9).该站大气N_2O浓度主要受人为活动排放的影响. 相似文献
548.
549.
用气相色谱/质谱(GC/MS)研究分析了环境中的半挥发性有机标准物。以十氟三苯基磷作调机物,对GC/MS仪器系统进行了调整,离子丰度值符合美国环保局(U.S.EPA)1986年推荐的离子丰度标准。测定了32种目标化合物的保留时间及相对保留因子RF值,结果表明除五氯苯酚不达标外,其余化合物的RF值均符合要求,31种目标化合物的加标回收率为21%~97%,相对标准偏差为3.1%~24.1%,符合美国环保局8270方法质量控制检验标准。最后对建立定量校正库与GC/MS分析进行了讨论 相似文献
550.
土壤和植物中硼酸的离子排斥色谱法分析研究 总被引:1,自引:0,他引:1
本文研究了用酒石酸-甘露醇作淋洗液,氢氧化钠作再生液测定土壤和植物中硼酸的离子排斥色谱条件。硼酸的检测限为0.05mg/l相对标准偏差1.85%,样品测定回收率为100±10%。 相似文献