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991.
992.
The application of in-tissue passive sampling to quantify chemical kinetics in fish bioconcentration experiments was investigated. A passive sampler consisting of an acupuncture needle covered with a PDMS tube was developed together with a method for its deployment in rainbow trout. The time to steady state for chemical uptake into the passive sampler was >1 d, so it was employed as a kinetically limited sampler with a deployment time of 2 h. The passive sampler was employed in parallel with the established whole tissue extraction method to study the elimination kinetics of 10 diverse chemicals in rainbow trout. 4-n-nonylphenol and 2,4,6-tri-tert-butylphenol were close to or below the limit of quantification in the sampler. For chlorpyrifos, musk xylene, hexachlorobenzene, 2,5-dichlorobiphenyl and p,p′-DDT, the elimination rate constants determined with the passive sampler method and the established method agreed within 18%. Poorer agreement (35%) was observed for 2,3,4-trichloroanisole and p-diisopropylbenzene because fewer data were obtained with the passive sampling method due to its lower sensitivity. The work shows that in-tissue passive sampling can be employed to measure contaminant elimination kinetics in fish. This opens up the possibility of studying contaminant kinetics in individual fish, thereby reducing the fish requirements and analytical costs for the determination of bioconcentration factors. 相似文献
993.
经济发展与农业面源污染关系的协整检验——基于三峡库区重庆段1992-2009年数据的分析 总被引:1,自引:0,他引:1
运用协整检验和Granger因果检验方法,考察了三峡库区重庆段1992-2009年经济发展与农业面源污染之间的相互关系。研究结果表明:①经济增长是影响三峡库区重庆段农业面源污染的主要原因,且种植业、养殖业和农村生活三大类污染源排放量与农村经济发展之间都具有协整关系;②短期内农业生产总值的变化引起三类农业污染源排放量的同方向变动,长期来看,农村经济发展对农业面源污染有减缓作用,这与传统的环境—经济增长库兹涅茨倒U型曲线所揭示的一般规律相同;③农业经济的发展和种植业、养殖业的污染排放量具有双向的因果关系,但是经济发展是农村生活污染排放量增长的原因,农村生活污染排放量不是经济增长的原因,它们之间是单向因果关系。因此,我们要密切关注库区经济增长对环境质量带来的负面效应,必须依赖科学技术进步,提高种植业中化肥、农药、农膜和秸秆等的利用率,根据当地农业发展的特点以及与河流的远近,规划好农业、林业、畜牧业的结构,大力发展环保型、生态型农业,以减轻农业面源污染,实现农业经济增长与保持环境质量之间的相互协调。 相似文献
994.
995.
Patrizia Stefanelli Tiziana Generali Danilo Attard Barbini Silvana Girolimetti Roberto Dommarco 《Journal of environmental science and health. Part. B》2013,48(7):523-529
In this work we report the results for estimating the measurement uncertainty (MU) following up the application of two different approaches, relatively the top-down procedure, by using proficiency test data. We have focused the estimation on the olive oil matrix. We used the analytical data obtained from five selected editions of the Proficiency Tests (PTs, from 2007 to 2011) on pesticide residues in olive oil to estimate the MU. These PTs have been organized by Istituto Superiore di Sanità annually in cooperation with International Olive Council (IOC) since 1997. The number of participants in each trial ranged from 10 to 43. We used a total of 34 pesticide results. The expanded uncertainty U (c) was calculated using a covering factor k = 2 for a confidence interval of 95%. In the approach 1, the within–laboratory reproducibility standard deviation is combined with estimates of the method and laboratory bias using PTs data. In the approach 2, the way of estimating the MU is based only on the bias that the laboratory has obtained participating in a sufficient number of the IOC proficiency tests. Comparing the relative expanded uncertainty based on these different approaches we notice values quite constant and close, from 42% to 48%. Moreover, these calculated expanded uncertainties are less than the default value of 50% (corresponding to a 95% confidence level), adopted from European guidance document SANCO based on the fit-for-purpose relative standard deviation (FFP-RSD). 相似文献
996.
柠檬酸浸出土壤中铜、锌的优化设计 总被引:1,自引:0,他引:1
以某工业废弃地土壤为供试材料,采用批次实验方法,研究了柠檬酸对重金属Cu、Zn的浸出效果。并在单因素实验基础上,探讨不同pH值、柠檬酸浓度、固液比和浸提时间等对浸出效果的影响,进而对实验条件进行正交优化组合,确定优化工艺参数为:pH值为3.2,柠檬酸浓度为0.4 mol/L,壤土固液比为1/10,土壤中Cu、Zn接近平衡的时间分别为1 h和1.5 h。结果表明,在此条件下,对这2种金属来说,Cu较Zn易释放,Cu、Zn的最大浸出率分别为74.8%和65.3%。柠檬酸浸提前后,土壤中有机质含量下降范围为0.61%~3.16%。单从土壤有机质含量来看,柠檬酸对土壤质量影响较小,具有较好的应用前景。 相似文献
997.
Shinji Sakurai Yoko Fujikawa Masumi Kakumoto Masataka Sugahara Tatsuhide Hamasaki Mikio Umeda 《Journal of environmental science and health. Part. B》2013,48(3):284-291
In this study, we investigated the behavior of estrogens in the rhizosphere of white clover (Trifolium repens, clover hereafter) with two different pot tests, using soil and agar as growth media. In a pot test using agar spiked with estrogen, the estrogen concentration in the agar with clover decreased to non-detectable levels within one month, while in the agar without clover, 60% of initially added estrogen remained after one month. The half-lives of estrone (E1) and 17β -estradiol (E2) in the agar with clover were 2.4–3.8 and 13.2 d, respectively. The dissipation of E1 followed first-order rate law, while that of E2 fitted a zero-order reaction, indicating that they had different mechanisms of dissipation from agar. In the soil pot test, the behavior of E1 and E2 was not influenced by clover. An initial rapid decrease in the amount of estrogen extracted by methanol/acetic acid was followed by persistence for 1–3 months, regardless of presence of clover. Moreover, in three weeks E1 and E2 were only partly degraded by microbes extracted from the soil used in the pot test. In this study, abiotic degradation of estrogens and sorption of estrogen to soil, rather than the effects of soil microbes and clover, contributed to the initial rapid dissipation of estrogens in the soil. However, the results of the agar pot test suggested that vegetation such as clover may significantly contribute to removal of estrogens when estrogens in aqueous phase are discharged with surface runoff and preferential flow after heavy rain in agricultural fields, or when present in soils with low estrogen sorptivity. 相似文献
998.
应用膨化技术对玉米秸秆进行预处理.在单因素实验基础上,以还原糖转化率为影响值设计正交实验,研究温度、pH、液固比、酶浓度及酶解时间五因素对纤维素酶解过程的影响.得出玉米秸秆糖化酶解最佳工艺条件为:温度48℃,pH 4.5,液固比8:1,酶浓度36.0 U/g,酶解时间25 h;在此工艺条件下还原糖转化率达到28.98%.扫描电镜表征对比观察可看出,膨化后玉米秸秆纤维素酶解充分;结合红外光谱对各组分特征基团分析表明,膨化后的玉米秸秆酶解的纤维素基团特征峰变化更为明显. 相似文献
999.
Goran Gajski Sanda Ravlić Željka Capuder Vera Garaj-Vrhovac 《Journal of environmental science and health. Part. B》2013,48(6):607-613
Wide distribution, stability and long persistence in the environment of dichlorodiphenyltrichloroethane (DDT), probably the best-known and most useful insecticide in the world, imposes the need for further examination of the effect of this chemical on human health and especially on the human genome. In this study, peripheral blood human lymphocytes from a healthy donor were exposed to 0.025 mg/L concentration of p,p′-DDT at different time periods (1, 2, 24 and 48 h). For the assessment of genotoxic effect, the new criteria for scoring micronucleus test and alkaline comet assay were used. Both methods showed that p,p′-DDT induces DNA damage in low concentration used in this research. Results of micronucleus test showed a statistically significant (p < 0.05) genotoxic effect of p,p′-DDT on human lymphocytes compared with corresponding control and a different exposure time. A comet assay also showed increased DNA damage caused in p,p′-DDT-exposed human lymphocytes than in corresponding control cells for the tail length. Results obtained by measuring the level of DNA migration and incidence of micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) indicate the sensitivity of these tests and their application in detection of primary genome damage after long-term exposure to establish the effect of p,p′-DDT on human genome. 相似文献
1000.
L. Delgado-Moreno L. Sánchez A. Castillo V. Pot A. Peña 《Journal of environmental science and health. Part. B》2013,48(3):241-248
A field experiment to determine the available bensulfuron-methyl (BSM) in the upper soil layer was conducted in an agricultural area in the South of Spain. To facilitate herbicide analysis, two application rates were employed, 200 g ha?1 and 5 kg ha?1. Samples of upper soil and soil solution were collected. Soil solution was sampled by means of metallic samplers, placed at a depth of 35 cm. In the plots receiving the lower dose ceramic suction, porous cups were also installed. Results from soil solution samples showed that the maximum BSM concentration was found after 8-10 days for the high irrigation supply (945 mm) and after 18-25 days for the lower irrigation regime (405 mm). The mathematical model FOCUSPELMO 1.1.1 was applied to interpret the data obtained in the field experiments. In general, there was a reasonable agreement between experimental and simulated data for soil samples, although the model did not acceptably predict herbicide concentrations in water soil samples. Ceramic cups sampled a higher soil water volume and more frequently than did the metallic samplers. However some variable results were attributed to preferential flow. 相似文献