Transfer rate of pesticide residues from medicinal plants in different types of extractive solutions

Abstract

Starting from the suspicion that the medicinal herbs may contain traces of pesticides and taking into account the risks of patients being exposed to contaminated products, the aim of this research was to evaluate the pesticide residues and the degree of their transfer (%) in three types of preparations (infusion, decoctionand cold maceration), for four medicinal plant species very often used in phytotherapy (Rosmarini folium, Menthae folium, Saturejae herba and Basilica herba). For each type of plant product, four samples were purchased from different manufacturers and they have been analyzed using gas chromatography- tandem mass spectrometry. One out of four samples of the same plant species contain at least one pesticide residue above the maximum level and shows a significant transfer of these residues in aqueous extractive solutions during extraction. The highest rate of pesticide transfer from medicinal plants was identified in infusions, recommended by many manufacturers.     

运用热脱附/GC/MS分析研究室内空气中TVOC浓度及种类分布

利用热脱附/GC/MS联用技术定性、定量(半定量)分析了多组有代表性的室内空气样品。结果表明,室内空气挥发性有机气体的主要成分是苯系物、烃类、醛酮类、酯类等;装修后3个月内的家居室内空气中的苯25%超标,甲苯58%超标,二甲苯79%超标,TVOC 100%超标;一年后,仅TVOC还有11%的超标。办公室情况类似。     

气相色谱法测定水和废水中的溴丙磷

试验了水和废水中溴丙磷的气相色谱分析法。采用二氯甲烷萃取,HP-110m×530μm×2 65μm大口径毛细管柱分离,火焰光度检测器(FPD)检测,得到了良好的分离效果。检出限可达0 0007mg/L(萃取10倍),相对标准差为2 6%。     

超声波提取-气相色谱法测定土壤中残留六六六和滴滴涕

采用气相色谱法毛细管色谱柱分离、电子捕获检测器检测土壤中残留的六六六和滴滴涕含量。取风干过筛的土壤样品，用丙酮、石油醚（1：）浸泡，超声波提取，浸泡液经浓硫酸净化后进样测定。当土壤样品取样量为10g时，方法检测限α-六六六，γ-六六六为0.001mg/kg,β-六六六、δ-六六六、op'-DDT和pp'-DDT为0.004mg/kg,pp'-DDE,pp'-DDD为0.002mg/kg。加标回收率在77%-100%之间，相对标准偏差为2.5%-8.5%。方法简便、灵敏。     

A wood preservative metabolite in river water

- A previously unknown pollutant in river water was identified to be 2-mercaptobenzothiazole (2-MBT) by interpretation and simulation of its GC/LRMS spectrum. Further GC/HRMS measurement of the isotope composition of the molecular ion verified this structure. 2-MBT is a well-known agent for corrosion inhibition and a stable metabolite of several other benzothiazoles. The present 2-MBT trace was most probably a metabolite of the wood preservative TCMTB which leaked from an upstream sawmill. The metabolite had been detected earlier in urine of the sawmill workers, but now was identified in the recipient water environment for the first time.     

Detection of indoor PCB contamination by thermal desorption of dust. A rapid screening method?

Although PCB in caulking materials has been forbidden for many years in most of Europe, including Denmark, there has been continued interest to measure PCB levels in the air of contaminated buildings and blood of the occupants (Mengon and Schlatter 1993, Fromme et al. 1996, Ewers et al. 1998, Currado and Harrad 1998, Gabrio et al. 2000). The relatively low priority for investigations of this contamination is probably due to the small quantities inhaled compared to exposure via food, and the rapid metabolism of the most volatile congeners demonstrated by low concentrations of all congeners in the blood of exposed persons (Ewers et al. 1998, Gabrio et al. 2000). There is, however, evidence that PCB containing caulking materials have been used even during the '90s (Fromme et al. 1996). In Denmark, it is estimated that 75 t PCB is still in buildings (Organization of Sealant Branch's Manufacturers and Distributors 2000). During an investigation of dust from buildings with excessive microbial growth (including 35 rooms from 9 buildings), the analysis of semivolatile compounds by thermal desorption-GC/MS of samples from a single building surprisingly revealed large amounts of PCBs containing 3, 4 and 5 chlorine atoms, 10-20 times the amounts found in samples from other buildings. Extraction of the dust by SFE followed by GC/ECD analysis for 12 PCB congeners showed that there was approximately 20 times the total PCB concentrations in dust from the polluted building compared to the levels in the other buildings. Subsequent headspace analysis of caulking material from the polluted building revealed this to be the source. Shelf dust functions as a passive sampling medium and, thus, can be used as a screening method to detect PCB and other semivolatile pollution indoors.     

Column experiments to study nonlinear removal of bacteriophages by passage through saturated dune sand

In a recent field study on dune recharge, bacteriophages MS2 and PRD1 were found to be removed 3 log10 over the first 2.4 m and only 5 log10 over the next 27 m. To understand the causes of this nonlinear removal, column experiments were carried out under conditions similar to the field: same recharge water, temperature (5 +/- 3 degrees C) and pore water velocity (1.5 m day(-1)). Soil samples were taken along a streamline between the recharge canal and the first monitoring well. Bacteriophage phiX174 was included for comparison. The high initial removal in the field was found not to be due to heterogeneity of phage suspensions but to soil heterogeneity. Phage removal rates correlated strongly positively with soil organic carbon content, and relatively strongly positively with silt content and the presence of ferric oxyhydroxides. Soil organic carbon content, silt content and the presence of ferric oxyhydroxides were found to decrease exponentially with travel distance. Removal rates of phiX174 were found to be 3-10 times higher than those of MS2 and PRD1 due to the lower electrostatic repulsion that the less negatively charged phiX174 experiences. It is suggested that the high initial removal in the field is due to the presence of favorable sites for attachment formed by ferric oxyhydroxides that decrease exponentially with travel distance. Similar removal rates may be found at both laboratory and field scale. However, due to local variations at field scale detailed knowledge on soil heterogeneity may be needed to enable a reliable prediction of removal.     

Multivariate Statistics of the Pyrolysis Products of High Molecular Components in Pulping Wastewaters to Explain Their Toxicity (6 pp)

Background, Aim and Scope At present, large-scale paper manufacture involves delignification and bleaching by elemental chlorine free (ECF) or totally chlorine free (TCF) processes. The wastewater is purified by secondary treatment (mechanical, chemical and biological) which removes most of the toxic substances from the discharge. However, we found residual toxicity in the high molecular (> 1000 D) matter (HMWM) of the discharge by test of the RET (reverse electronic transfer) inhibition. This fraction consists mainly of polydisperse lignin (LIG) and carbohydrate (CH) macromolecules. Structural units in these molecules are studied by pyrolysis gas chromatography / mass spectrometry (Pyr-GC/MS). In the present work, our aim was to find out those structural units which could explain the RET toxicity of LIG or CH molecules. We compared statistically RET toxicity values of the HMWM samples from treated wastewaters of pilot pulping experiments and intensity variation of the pyrolysis product gas chromatograms of these samples. This application is a novel study procedure. Methods Pyrolysis products (Py-GC/MS results) and inhibition of RET (reverse electronic transport toxicity) as TU50 and TU20 of HMWM (High Molecular Weight Material; Mw > 1000 D) were compared by multivariate statistics. The samples were from laboratory pilot stages of TCF (Totally Chlorine Free) and ECF (Elemental Chlorine Free) manufacture of softwood pulp. Py-GC/MS was done without and with addition of TMAH (Tetra Methyl Ammonium Hydroxide). The name and structure of each abundant fragment compound was identified from its retention time and mass spectrum compared to authentic reference compounds or literature. Four sets of Toxicity Units (TUs) and GC peak areas of the pyrolysis fragments were obtained. The data were normalized by division with LIG (lignin content of each sample). TU values were dependent and the fragment values independent (explanatory) variables in statistical treatments by SPSS system. Separate analyses of correlations, principal components (PCA) and stepwise multiple linear regression (SMLR) were performed from the four sample sets TCF and ECF with and without TMAH. Results and Discussion From the CH fragments, 2-furfural in TCF, and from the LIG fragments, styrene in ECF showed the highest probabilities to originate from source structures of toxicity. Other possible compounds in concern were indicated to be CH fragment 2-methyl-2-cyclopenten-1-one in ECF and LIG fragments 2-methoxy-4-methylphenol, 4,5-dimethoxy-2-methylphenol and 2-methylphenol in TCF.     

固相微萃取-毛细管气相色谱法快速分析水中酞酸酯

用固相微萃取富集水中酞酸酯，毛细管气相色谱分离分析，整个分析过程只需50min，检出限可达0.01-40.0μg／L，实验表明，固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术，具有分析时间短、灵敏度高、无需有机溶剂的优点，已用于地面水源、海水、饮用水中酞酸酯含量的测定。     

PCDTs in the environment

Polychlorinated dibenzothiophenes (PCDTs) are sulfur analogues of polychlorinated dibenzofurans. Recently, PCDTs have been found in stack gas and fly ash samples, pulp mill effluents, sediments and in some aquatic organisms. PCDTs have been analyzed by high resolution GC/MS and by other GC-MS techniques. Combustion is until now the major known source of PCDTs in the environment. Tri-, tetra- and pentaCDTs in concentrations approaching those of PCDTs have been analyzed in some samples from waste incineration and metal reclamation. Concentrations of PCDTs in pulp mill effluents have been found to be quite low. 2378-TeCDT was found to be the major TeCDT isomer in some pulp mill effluents. Preliminary toxicological investigations have shown that PCDTs possess some kind of dioxin type toxicity.