GC–MS combined with chemometric techniques for the quality control and original discrimination of Curcumae longae rhizome: Analysis of essential oils

Curcumae longae rhizome is a widely used traditional herb in many countries. Various geographical origins of this herb might lead to diversity or instability of the herbal quality. The objective of this work was to establish the chemical fingerprints for quality control and find the chemical markers for discriminating these herbs from different origins. First, chemical fingerprints of essential oil of 24 C. longae rhizome from four different geographical origins in China were determined by GC–MS. Then, pattern recognition techniques were introduced to analyze these abundant chemical data in depth; hierarchical cluster analysis was used to sort samples into groups by measuring their similarities, and principal component analysis and partial least‐squares discriminate analysis were applied to find the main chemical markers for discriminating these samples. Curcumae longae rhizome from Guangxi province had the highest essential oil yield (4.32 ± 1.45%). A total of 46 volatile compounds were identified in total. Consistent results were obtained to show that C. longae rhizome samples could be successfully grouped according to their origins, and turmerone, ar‐turmerone, and zingiberene were the characteristic components for discriminating these samples of various geographical origins and for quality control. This finding revealed that fingerprinting analysis based on GC–MS coupled with chemometric techniques could provide a reliable platform to discriminate herbs from different origins, which is a benefit for quality control.     

Human health risk assessment of heavy metals via consumption of contaminated vegetables collected from different irrigation sources in Lahore,Pakistan

Soil pollution with heavy metals due to discharge of untreated urban and industrial wastewater is a major threat to ecological integrity and human well-being. The presenting study aimed to determine human health risks associated via food chain contamination of heavy metals routing from irrigation of urban and industrial wastewater. Irrigated water, soil and vegetables were analyzed for Cr²⁺, Co²⁺, Ni²⁺, Cu²⁺, Pb²⁺, Cd²⁺, Mn²⁺ and Zn²⁺; transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Cr²⁺, Pb²⁺ and Cd²⁺ in vegetables cultivated by wastewater exceeded the permissible limits (European Union, 2002) while TF was lower for all metals except Co²⁺ and HRI was found to be maximum for Spinacia oleracea (2.42 mg/kg) and Brassica campestris (2.22 mg/kg) cultivated by wastewater. S. oleracea, B. campestris, Coriandrum sativum posed a severe health risk with respect to Cd and Mn.     

安全评价服务质量监管三方博弈关系研究

安全评价服务质量监管是有效防止安全生产条件差的企业从事生产经营活动,提高安全生产管制效力的重要手段。为了探究制约安评机构败德行为的有效途径,以安全评价服务市场中各参与主体为研究对象,针对安评服务质量低下、安评质量监管不力的问题,构建不完全信息下地方安监部门、安评机构、高危行业企业三方静态博弈模型,对模型均衡解进行分析,从利益实现机制出发,探索提高监管效力进而有效保障安全评价服务质量的关键条件。研究结果表明,地方安监部门、安评机构、企业行动策略的选择主要取决于各自合规行动的直接成本、违规惩罚力度以及违规被发现的概率等参数。研究结论与政策建议对提高我国安全评价服务质量具有现实指导意义。     

当代大学物理实验教学方法改革探析

在大学物理实验教学过程中应以大学物理实验课程的培养计划和实施素质教育为目标,采取灵活多变的实验教学方法,注重学生的主体作用,引导学生积极思考,重视教学互动,重点培养学生的研究创新能力和实际操作动手能力。同时结合当今科技的最新发展,注重实验的科技性、创新性、实用性,以科研方式组织教学,充分激发学生对科学研究的兴趣,提高学生的综合素质。     

Quality assessment and authentication of virgin olive oil by NMR spectroscopy: A critical review

Nuclear Magnetic Resonance (NMR) Spectroscopy has been extensively used for the analysis of olive oil and it has been established as a valuable tool for its quality assessment and authenticity. To date, a large number of research and review articles have been published with regards to the analysis of olive oil reflecting the potential of the NMR technique in these studies. In this critical review, we cover recent results in the field and discuss deficiencies and precautions of the three NMR techniques (¹H, ¹³C, ³¹P) used for the analysis of olive oil. The two methodological approaches of metabonomics, metabolic profiling and metabolic fingerprinting, and the statistical methods applied for the classification of olive oils will be discussed in critical way. Some useful information about sample preparation, the required instrumentation for an effective analysis, the experimental conditions and data processing for obtaining high quality spectra will be presented as well. Finally, a constructive criticism will be exercised on the present methodologies used for the quality control and authentication of olive oil.     

Residues of some organophosphorus pesticides on and in fruits and vegetables available in Poland,an assessment based on the European union regulations and health assessment for human populations

Abstract

The use of organophosphorus pesticides is undeniably beneficial in agriculture and veterinary medicine, but their excessive use can pollute the environment, as well as contaminate foodstuffs. The objective of this study was to assess contamination of vegetables and fruits available in Poland by organophosphate pesticides (ethoprophos, diazinon, chlorpyrifos, chlorpyrifos-methyl, parathion-methyl, fenchlorphos, merfos,, as well as to assess a potential health risk posed to consumers. The pesticide content was determined by gas chromatography-mass spectrometry (GC-MS). The pesticides were detected in the peel and pulp of vegetables and fruits from Polish crops, as well as imported ones. Pesticide levels in most products were higher in the peel than in the pulp. Neither chlorpyrifos-methyl nor fenchlorphos were found in the material under study. Chlorpyrifos was the pesticide occurring in the highest levels in the peel of both vegetables (31?ng?·?g^?1 w.w.) and fruit (9.3?ng?·?g^?1 w.w.). The Maximum Residue Level (MRL) for parathion-methyl was exceeded in some samples of zucchini pulp of Spanish origin and in the peel of potato from Poland. But levels of other pesticides in the studied vegetables and fruits were significantly lower than the current MRLs. The assessment of consumer health risk showed a significantly lower Lifetime Average Daily Dose (LADD) of pesticides under this study comparing to the Acceptable Daily Intake (ADI). Moreover, the Hazard Quotient (HQ) was low with a maximum of 3.93?×?10^?2 for vegetables and 4.26?×?10^?3 for fruits. These estimated HQs were within the safe acceptable limits, indicating low risk to human populations from exposure to organophosphorus pesticides in the study area.     

The physicochemical basis of QSARs for baseline toxicity

The physico-chemical properties relevant to the equilibrium partitioning (bioconcentration) of chemicals between organisms and their respired media of water and air are reviewed and illustrated for chemicals that range in hydrophobicity. Relationships are then explored between freely dissolved external concentrations such as LC50s and chemical properties for one important toxicity mechanism, namely baseline toxicity or narcosis. The ‘activity hypothesis’ proposed by Ferguson in 1939 provides a coherent and compelling explanation for baseline toxicity of chemicals in both water- and air-respiring organisms, as well as a reference point for identifying more specific toxicity pathways. From inhalation studies with fish and rodents, narcosis is shown to occur at a chemical activity exceeding approximately 0.01 and there is no evidence of narcosis at activities less than 0.001. The activity hypothesis provides a framework for directly comparing the toxic potency of chemicals in both air- and water-breathing animals. The activity hypothesis is shown to be consistent with the critical body residue concept, but it has the advantage of avoiding the confounding effect of lipid content of the test organism. It also provides a theoretically sound basis for assessing the baseline toxicity of mixtures. It is suggested that since activity is readily calculated from fugacity, observed or predicted environmental abiotic and biotic fugacities can be used to evaluate the potential for baseline toxicity. Further, models employing fugacity or activity can be used to improve the experimental design of bioassays, thus possibly reducing unnecessary animal testing.     

Using chemical categories to fill data gaps in hazard assessment

Hazard assessments of chemicals have been limited by the availability of test data and the time needed to evaluate the test data. While available data may be inadequate for the majority of industrial chemicals, the body of existing knowledge for most hazards is large enough to permit reliable estimates to be made for untested chemicals without additional animal testing. We provide a summary of the growing use by regulatory agencies of the chemical categories approach, which groups chemicals based on their similar toxicological behaviour and fills in the data gaps in animal test data such as genotoxicity and aquatic toxicity. Although the categories approach may be distinguished from the use of quantitative structure–activity relationships (QSARs) for specific hazard endpoints, robust chemical categories are founded on quantifying the chemical structure with parameters that control chemical behaviour in conventional hazard assessment. The dissemination of the QSAR Application Toolbox by the Organisation for Economic Cooperation and Development (OECD) is an effort to facilitate the use of the categories approach and reduce the need for additional animal testing.     

Use of Knowledge Bases and QSARS to Estimate the Relative Ecological Risk of Agrichemicals: A Problem Formulation Exercise

Abstract

Ecological risk assessments can be used to establish the likelihood that an adverse effect will result from exposure to one or more chemicals. When evaluating contaminated sites with many chemicals present, risk assessors must grapple with the problem of quickly identifying the chemicals that are most likely to be of concern, based on effect and exposure assessment information. Many times data gaps exist and the risk assessor is left with decisions on which models to use to estimate the parameter of concern. In the present paper, a procedure is presented for ranking agrichemicals, utilizing the ASTER (ASsessment Tools for the Evaluation of Risk) system. The procedure was employed to rank the relative ecological risk of forty-nine pesticides historically used in agricultural sites in the Walnut Creek watershed near Ames, Iowa, USA. Empirical data from the ASTER system were used when available in the associated data-bases, and quantitative structure-activity relationships and expert systems were invoked when data were lacking. Separate rankings were conducted based on major species taxonomic groupings. Resulting toxic effects thresholds were compared to surface water concentrations.