Assessing the ecotoxicity of pesticide transformation products

Once released to the environment, pesticides may be degraded by abiotic and biotic processes. While parent compounds are assessed in detail in many regulatory schemes, the requirements for the assessment of transformation products are less well developed. This study was therefore performed to explore the relationships between the toxicity of transformation products and their parent compounds and to develop a pragmatic approach for use in the risk assessment of transformation products. Data were obtained on the properties and ecotoxicity of transformation products arising from a wide range of pesticides. Generally, transformation products were less toxic to fish, daphnids, and algae than their parent compound. In instances where a product was more toxic, the increase in toxicity could be explained by either (1) the presence of a pesticide toxicophore; (2) the fact that the product is the active part of a propesticide; (3) the product is accumulated to a greater extent than the parent compound; or (4) the product has a more potent mode of action than the parent. On the basis of the findings, an approach has been proposed to estimate the ecotoxicity of transformation products based on chemical structure and data on the toxicity of the parent compound. The assessments can be performed at an early stage in the risk assessment process to identify those substances that require further testing.     

Recent advances in environmental risk assessment of transformation products

When micropollutants degrade in the environment, they may form persistent and toxic transformation products, which should be accounted for in the environmental risk assessment of the parent compounds. Transformation products have become a topic of interest not only with regard to their formation in the environment, but also during advanced water treatment processes, where disinfection byproducts can form from benign precursors. In addition, environmental risk assessment of human and veterinary pharmaceuticals requires inclusion of human metabolites as most pharmaceuticals are not excreted into wastewater in their original form, but are extensively metabolized. All three areas have developed their independent approaches to assess the risk associated with transformation product formation including hazard identification, exposure assessment, hazard assessment including dose-response characterization, and risk characterization. This review provides an overview and defines a link among those areas, emphasizing commonalities and encouraging a common approach. We distinguish among approaches to assess transformation products of individual pollutants that are undergoing a particular transformation process, e.g., biotransformation or (photo)oxidation, and approaches with the goal of prioritizing transformation products in terms of their contribution to environmental risk. We classify existing approaches for transformation product assessment in degradation studies as exposure- or effect-driven. In the exposure-driven approach, transformation products are identified and quantified by chemical analysis followed by effect assessment. In the effect-driven approach, a reaction mixture undergoes toxicity testing. If the decrease in toxicity parallels the decrease of parent compound concentration, the transformation products are considered to be irrelevant, and only when toxicity increases or the decrease is not proportional to the parent compound concentration are the TPs identified. For prioritization of transformation products in terms of their contribution to overall environmental risk, we integrate existing research into a coherent model-based, risk-driven framework. In the proposed framework, read-across from data of the parent compound to the transformation products is emphasized, but limitations to this approach are also discussed. Most prominently, we demonstrate how effect data for parent compounds can be used in combination with analysis of toxicophore structures and bioconcentration potential to facilitate transformation product effect assessment.     

Occurrence of pesticide residues and transformation products in different types of dietary supplements

The purpose of this study was to evaluate the presence of pesticide residues and transformation products in dietary supplement products. Thirty-two samples were analysed to determine 177 pesticides by gas chromatography–tandem mass spectrometry (GC-MS/MS) and 333 pesticides by liquid chromatography–high-resolution mass spectrometry (LC-HRMS). Pesticides were extracted from different kinds of dietary supplements by the use of a modified QuEChERS extraction method. Six samples contained pesticide residues at concentration up to 92.7 µg kg^?1, but only butralin exceeded the maximum residue limits set for raw material. In addition to target compounds, LC-HRMS enables the simultaneous detection of non-target pesticides. In this case, transformation products of pesticides were detected in the analysed samples using HRMS analyser (Exactive-Orbitrap). These compounds were not included in the original method, and they were monitored as post-target compounds, knowing their molecular formula and exact mass. Mass accuracy was always < 2 ppm, corresponding to a maximum mass error. The positive findings endorse the idea that a deeper and continuous investigation of pesticide residues and transformation products in dietary supplement products is necessary in order to guaranty consumer’s safety.     

The microbiological quality of drinking water supplies of Izmir City: the incidence of Yersinia enterocolitica

A total of 100 water samples collected from piped public supplies, wells with and without motor pumps, springs and commercially bottled spring waters were microbiologically examined. In order to determine microbiological quality, aerobic bacterial and coliform counts were estimated and the presence of Escherichia coli and Yersinia enterocolitica was investigated. Of the samples tested, 85 of them met the specifications set by TFR (Turkish Food Regulation) for coliforms, whereas 72 of them met the specifications for aerobic bacteria. The number of samples containing Y. enterocolitica and E. coli were found to be 6 and 5, respectively.     

农产品和水体中农药残留检测技术研究进展

农药残留是指由于使用农药而残留于农作物、水体、土壤等的农药原体和代谢物。农药具有毒性强、稳定性好、生物聚集性等特点,极易在环境中发生富集,最终进入人体,其残留问题已对人类健康和环境中其他生物体形成极大威胁。因此监测食品或环境中的农药残留水平对人类健康和保护生物多样性具有十分重要的作用。随着科学技术的不断探索和发展,农药残留检测技术也取得了重大突破。本研究总结了农药残留的方式和危害;分析了农药残留检测中常用的前处理方法(液液萃取、固相萃取、QuEChERS提取法和其他方法),对比了几种方法的优缺点;对近年来农药残留的传统分析技术的最新应用和新型的检测分析技术及其应用进行了综述,并对当前领域存在的问题和未来的发展方向进行了总结。     

Ozonation of carbamazepine in drinking water: identification and kinetic study of major oxidation products

Kinetics and product formation of the anti-epileptic drug carbamazepine (CBZ) were investigated in lab-scale experiments during reactions with ozone and OH radicals. Ozone reacts rapidly with the double bond in CBZ, yielding several ozonation products containing quinazoline-based functional groups. The structures for three new oxidation products were elucidated using a combination of mass spectrometric and NMR techniques. The three products were determined to be 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD), and 1-(2-benzoic acid)-(1H,3H)-quinazoline-2,4-dione (BaQD). Additional kinetic studies of the ozonation products showed very slow subsequent oxidation kinetics with ozone (second-order rate constants, kO3 = approximately 7 M(-1)s(-1) and approximately 1 M(-1)s(-1) at pH = 6 for BQM and BQD, respectively). Rate constants for reactions with OH radicals, kOH, were determined as approximately 7 x 10(9) M(-1)s(-1) for BQM and approximately 5 x 10(9)M(-1)s(-1) for BQD. Thus, mainly reactions with OH radicals lead to their further oxidation. A kinetic model including ozone and OH radical reactions allows a prediction of the time-dependent product distribution during ozonation of natural waters. In Rhine River water, CBZ spiked at 500 ng/L was completely oxidized by ozone with applied doses > or =0.3 mg/L. To confirm that the two major ozonation products BQM and BQD are produced as a result of the ozonation of a CBZ-containing natural water, Lake Zurich water samples were spiked with CBZ (1 microM, 236 microg/L). The oxidation products were identified via LC-UV. Concentrations of 0.48 and 0.15 microM for BQM and BQD, respectively, were measured for an ozone dose of 1.9 mg/L. BQM and BQD were also identified in ozonated water from a German waterworks containing CBZ in its raw water with 0.07-0.20 microg/L. Currently, there are no data available on the biological effects of the formed oxidation products.     

Mycobacterium avium subsp. paratuberculosis in dairy products, meat, and drinking water

Mycobacterium avium subsp. paratuberculosis (Map) is the cause of Johne's disease, a chronic infection of the gut, in ruminant animals that provide milk and/or meat for human consumption. Map also may be involved in Crohn's disease and type 1 diabetes in humans. Although the role of Map in human diseases has not been established, minimizing the exposure of humans to the organism is considered desirable as a precautionary measure. Infected animals can shed Map in feces and milk, and the organism can become disseminated in tissues remote from the gut and its associated lymph nodes. The presence of at least some Map in raw milk and meat and in natural waters is likely, but the numbers of Map in those foods and waters should be reduced through cooking or purification. The available information relating to Map in milk and dairy products, meats, and drinking water is reviewed here for assessment of the risks of exposure to Map from consumption of such foods and water.     

Fate of foodborne bacterial pathogens in pesticide products

The effects of diluting concentrated pesticide products with water containing Escherichia coli O157:H7 (human, bovine and ground meat strains), Salmonella typhimurium, Salmonella enteritidis, Shigella sonnei, Shigella flexneri and Listeria monocytogenes were investigated. Individual cultures were inoculated at about 10² colony‐forming units (cfu) ml^?1 into the following commercial pesticide products—Roundup, Poast & Merge, Gramoxone, Afolan, 2,4‐D amine, Dithane M45, Benlate, Bravo 500, Ridomil 240EC, Thiram 75WP, Sevin XLR+, Lorsban 4E, Diazinon 500, Ambush 500EC and Lagon 480E—following dilution with sterile tap water to recommended spray application concentrations (pesticide solution). Following incubation at 22 °C for 1 h, survivor levels for all three E coli O157:H7 strains in pesticide solutions of Roundup, Poast & Merge, Gramoxone, Dithane M45, Ridomil 240EC and Lagon 480E were lower (P ≤ 0.05) compared to their survival in water. In several pesticide solutions (Afolan, Bravo 500, Lorsban 4E and Ambush 500EC), survivor levels were no different (P≥0.05) from the control after 1 h; however, by 24 h, population levels of all strains in these four pesticide solutions were higher (P ≤ 0.05) than those observed at 1 h. Overall, similar survivor or growth patterns were observed with the remaining bacteria, with the exception of S flexneri. For this bacterium, survival or growth was poor, especially in Bravo 500, which consistently supported substantial growth of the other micro‐organisms. Time course growth studies over 96 h at 22 °C were conducted with Salmonella, Shigella, Listeria and E coli O157:H7 in solutions of Afolan, Bravo 500, Lorsban 4E and Ambush 500EC. Overall, a 100 to 1060‐fold increase in population was usually obtained in these pesticide solutions by 96 h. Changes in either the initial inoculum level of E coli O157:H7 from about 10² to 10⁴ cfu ml^?1 or temperature (from 20–22 to 31 °C) and concentration (from 0.5 to 1.5 times the recommended spray concentration) were shown to affect its growth in the pesticide solutions. The findings of this study indicate that some pesticide products, when diluted using contaminated water, may have the potential to promote growth of pathogens which could increase the risk of more widespread contamination of standing crops, including fruits. © 2001 Society of Chemical Industry     

Hygienic evaluation of nitrate levels in drinking water and vegetable food products in various regions of Lithuania

Significantly higher nitrate content was detected in drinking water and vegetables grown by the rural population in the regions where industrial enterprises producing chemical fertilizers are located, as compared to the control regions. It has been concluded that a special attention should be paid to the daily level of nitrates ingested by the population (especially by children) in the industrial regions of the Republic and to their health state.     

Analytical methods for pesticide residue determination in bee products

Monitoring pesticide residues in honey, wax, and bees helps to assess the potential risk of these products to consumer health and gives information on the pesticide treatments that have been used on the field crops surrounding the hives. The present review seeks to discuss the basic principles and recent developments in pesticide analysis in bee products and their application in monitoring programs. Consideration is given to extraction, cleanup, chromatographic separation, and detection techniques.     

Determination of atrazine and degradation products in Luxembourgish drinking water: origin and fate of potential endocrine-disrupting pesticides

Several pesticides have been hypothesized to act as endocrine-disrupting compounds, exhibiting hormonal activity and perturbing normal physiological functions. Among these, especially s-triazine herbicides have received increased attention. Despite being banned in many countries, including the European Union, atrazine is still the world's most widely used herbicide. Despite its discontinued use, considerable concentrations of atrazine and its degradation products, mainly desethylatrazine (DEA) and deisopropylatrazine (DIA), are still found in the environment, including drinking water sources. The aim of this investigation was to study concentrations of especially s-triazine herbicides and major degradation products in drinking water, including spring water, tap water and bottled water in Luxembourg. Spring water (2007/2008/2009, n?=?69/69/69), tap water (2008/2009, n?=?19/26), and bottled water (2007/2008/2009, n?=?5/13/7) were sampled at locations in Luxembourg and investigated for pesticides by LC-ESI-MS/MS. Atrazine was the predominant triazine, detectable in many spring water locations, tap and bottled water, ranging (mean) from 0–57 (9), 0–44 (4), and 0–4 (1) ng?l^?1, respectively. DEA and DIA in spring water ranged (mean) from 0–120 (19) and 0–27 (3) ng?l^?1, with higher concentrations from agricultural areas and low molar ratios of DEA:atrazine <0.5 and high ratios of atrazine:nitrate suggesting point-source contamination. Levels (mean) of DEA and DIA in tap water were 0–62 (14) and 0–6 (<1) ng?l^?1 and in bottled water 0–11 (2) and 0–7 (2) ng?l^?1. Simazine and other triazines were detected in traces (<5?ng?l^?1). Thus, the conducted monitoring suggested the presence of low concentrations of s-triazines in raw and finished water, presumably partly due to non-agricultural contamination, with concentrations being below thresholds advocated by the European Union Directive 98/83/EC.     

Determination of atrazine and degradation products in Luxembourgish drinking water: origin and fate of potential endocrine-disrupting pesticides

Several pesticides have been hypothesized to act as endocrine-disrupting compounds, exhibiting hormonal activity and perturbing normal physiological functions. Among these, especially s-triazine herbicides have received increased attention. Despite being banned in many countries, including the European Union, atrazine is still the world's most widely used herbicide. Despite its discontinued use, considerable concentrations of atrazine and its degradation products, mainly desethylatrazine (DEA) and deisopropylatrazine (DIA), are still found in the environment, including drinking water sources. The aim of this investigation was to study concentrations of especially s-triazine herbicides and major degradation products in drinking water, including spring water, tap water and bottled water in Luxembourg. Spring water (2007/2008/2009, n?=?69/69/69), tap water (2008/2009, n?=?19/26), and bottled water (2007/2008/2009, n?=?5/13/7) were sampled at locations in Luxembourg and investigated for pesticides by LC-ESI-MS/MS. Atrazine was the predominant triazine, detectable in many spring water locations, tap and bottled water, ranging (mean) from 0-57 (9), 0-44 (4), and 0-4 (1) ng?l(-1), respectively. DEA and DIA in spring water ranged (mean) from 0-120 (19) and 0-27 (3) ng?l(-1), with higher concentrations from agricultural areas and low molar ratios of DEA:atrazine <0.5 and high ratios of atrazine:nitrate suggesting point-source contamination. Levels (mean) of DEA and DIA in tap water were 0-62 (14) and 0-6 (<1) ng?l(-1) and in bottled water 0-11 (2) and 0-7 (2) ng?l(-1). Simazine and other triazines were detected in traces (<5?ng?l(-1)). Thus, the conducted monitoring suggested the presence of low concentrations of s-triazines in raw and finished water, presumably partly due to non-agricultural contamination, with concentrations being below thresholds advocated by the European Union Directive 98/83/EC.     

农产品中农药残留预警系统的构建

随着社会经济的快速发展,人民生活水平的不断提高,民众对农产品安全问题也越来越关注.影响农产品安全的一个重要因素,就是农药残留问题.目前对农药残留的研究主要集中在检测技术和监测等方面,但缺乏对农药残留预警工作的研究探讨.因此,该文在介绍构建农产品农药残留预警系统重要意义的基础上,提出了建立农产品农药残留预警系统的原理和基本框架,同时阐述了其主要功能,为其它食品安全关键项目预警系统的建立提供参考.     

Effect of commercial processing on pesticide residues in orange products

The effect of commercial processing of orange juice on pesticide residues was investigated, and the processing factors of all orange products and by-products were also determined. The pesticide residues were strengthened using field trials and detected using Ultra-performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS). The results showed that the pesticide residues were mainly distributed in orange peels, the reduction of residue levels ranged from 43.6 to 85.4% during washing process. One percent to 4.5% of initial residues contained in the squeezed juice, 7–94.7% of the total relative residues were distributed in pomace. Filtrating could further reduce all the residue levels, ranging from 96.0–99.4% relative to unwashed whole fruits. After sterilization, there was only 0.5–3.1% of the residues contained in Not from Concentrate juice (NFC juice). 0.2–7.1% of the total relative residues was contained in concentrated juice, comparing with the filtrated juice; however, the concentration of cypermethrin and prochloraz was decreased, but the other 3 pesticides were increased. The residue levels of imidacloprid and carbendazim in orange oil were reduced but abamectin, prochloraz, and cypermethrin were concentrated, and the concentrated factor was 28.214, 5.232, and 5.621, respectively.     

Seasonal variations in concentrations of pharmaceuticals and personal care products in drinking water and reclaimed wastewater in southern California

Southern California imports nearly all of its potable water from two sources: the Colorado River and the California State Water Project (Sacramento-San Joaquin River Basin). Sewage treatment plant effluent (STPE) heavily impacts both of these sources. A survey of raw and treated drinking water from four water filtration plants in San Diego County showed the occurrence of several polar organic "pharmaceuticals and personal care products" (PPCP). These included phthalate esters, sunscreens, clofibrate, clofribric acid, ibuprofen, triclosan, and DEET. Several of these were also found in the finished water, such as di(ethylhexyl) phthalate, benzophenone, ibuprofen, and triclosan. Occurrence and concentrations of these compounds were highly seasonally dependent, and reached maximums when the flow of the San Joaquin River was low and the quantity of imported water was high. The maximum concentrations of the PPCPs measured in the raw water were correlated with low flow conditions in the Sacramento-San Joaquin Delta that feeds the State Water Project. The PPCP concentrations in raw imported water in the summer months approached that of reclaimed nonpotable wastewater.