175 research outputs found
Supplementary_information – Supplemental material for Compound Identification Using Liquid Chromatography and High-Resolution Noncontact Fraction Collection with a Solenoid Valve
No full textSupplemental material, Supplementary_information for Compound Identification Using Liquid Chromatography and High-Resolution Noncontact Fraction Collection with a Solenoid Valve by Willem Jonker, Koen de Vries, Niels Althuisius, Dick van Iperen, Elwin Janssen, Rob ten Broek, Corine Houtman, Nick Zwart, Timo Hamers, Marja H. Lamoree, Bert Ooms, Johannes Hidding, Govert W. Somsen and Jeroen Kool in SLAS Technology</p
Accurate Prediction of the Response of Freshwater Fish to a Mixture of Estrogenic Chemicals
No full textReproduced with permission from Environmental Health Perspectives.Existing environmental risk assessment procedures are limited in their ability to evaluate the combined effects of chemical mixtures. We investigated the implications of this by analyzing the combined effects of a multicomponent mixture of five estrogenic chemicals using vitellogenin induction in male fathead minnows as an end point. The mixture consisted of estradiol, ethynylestradiol, nonylphenol, octylphenol, and bisphenol A. We determined concentration–response curves for each of the chemicals individually. The chemicals were then combined at equipotent concentrations and the mixture tested using fixed-ratio design. The effects of the mixture were compared with those predicted by the model of concentration addition using biomathematical methods, which revealed that there was no deviation between the observed and predicted effects of the mixture. These findings demonstrate that estrogenic chemicals have the capacity to act together in an additive manner and that their combined effects can be accurately predicted by concentration addition. We also explored the potential for mixture effects at low concentrations by exposing the fish to each chemical at one-fifth of its median effective concentration (EC50). Individually, the chemicals did not induce a significant response, although their combined effects were consistent with the predictions of concentration addition. This demonstrates the potential for estrogenic chemicals to act additively at environmentally relevant concentrations. These findings highlight the potential for existing environmental risk assessment procedures to underestimate the hazard posed by mixtures of chemicals that act via a similar mode of action, thereby leading to erroneous conclusions of absence of risk.European Commission under the 5th Framework Programme (contract EVK1-2001-00091)
Organophosphate ester metabolites in human breast milk determined by online solid phase extraction coupled to high pressure liquid chromatography tandem mass spectrometry
No full textThe analysis of metabolites of organophosphate esters (OPEs) in human breast milk is essential to evaluate OPE and OPE metabolite exposure of newborns. In the current study, an analytical method which only needs a small amount of breast milk (100 μl) was developed and validated for six diester metabolites and three hydroxylated metabolites applying salt-induced liquid–liquid extraction (SI-LLE) and dispersive solid phase extraction (d-SPE) for sample preparation and online solid phase extraction coupled to high pressure chromatography tandem mass spectrometry (online-SPE-HPLC-MS/MS) for quantitative measurement. The final method consisted of an extraction with formic acid (FA)/acetonitrile (1:200, v/v) and a cleanup with C18 d-SPE. The final extracts were trapped on a C18 cartridge with application of a wash step of 2 ml 0.1% FA milli-Q/methanol (98:2, v/v). Method detection limits (MDLs) ranging from 21.7 ng/l for BBOEHEP to 500 ng/l for BCIPP and average recoveries ranging from 58% for 5-OH-EHDPHP to 120% for BCIPP were achieved. Thirty-three breast milk samples from the LINC (Linking EDCs in maternal Nutrition to Child health) cohort collected in three distinct areas in The Netherlands were analyzed using the validated method. BCEP, BCIPP, BCIPHPP, BDCIPP, and 5-OH-EHDPHP were not detected in any of the samples, while BBOEP was the most frequently detected metabolite with a concentration range of <MDL to l.47 ng/ml, followed by DPhP and BBOEHEP, detected in ranges of <MDL to 0.09 and <MDL to 0.027 ng/ml. The results indicated that OPEs entering the human body are only to a limited extent excreted via breast milk.</p
Tissue-specific metabolism of benzo[a]pyrene in rainbow trout (Oncorhynchus mykiss): a comparison between the liver and immune organs.
No full textPolycyclic aromatic hydrocarbons (PAHs) are immunotoxicants in fish. In mammals, phase I metabolites are believed to be critically involved in the immunotoxicity of PAHs. This mechanism has been suggested for fish as well. The present study investigates the capacity of immune organs (head kidney, spleen) of rainbow trout, Oncorhynchus mykiss, to metabolize the prototypic PAH, benzo[a]pyrene (BaP). To this end, we analyzed 1) the induction of enzymatic capacity measured as 7-ethoxyresorufin-O-deethylase (EROD) activity in immune organs compared with liver, 2) the organ profiles of BaP metabolites generated in vivo, and 3) rates of microsomal BaP metabolite production in vitro. All measurements were done for control fish and for fish treated with an intraperitoneal injection of 15 mg BaP/kg body weight. In exposed trout, the liver, head kidney, and spleen contained similar levels of BaP, whereas EROD induction differed significantly between the organs, with liver showing the highest induction factor (132.8×), followed by head kidney (38.4×) and spleen (1.4×). Likewise, rates of microsomal metabolite formation experienced the highest induction in the liver of BaP-exposed trout, followed by the head kidney and spleen. Microsomes from control fish displayed tissue-specific differences in metabolite production. In contrast, in BaP-exposed trout, microsomes of all organs produced the potentially immunotoxic BaP-7,8-dihydrodiol as the main metabolite. The findings from this study show that PAHs, like BaP, are distributed into immune organs of fish and provide the first evidence that immune organs possess inducible PAH metabolism leading to in situ production of potentially immunotoxic PAH metabolites
Pesticide residue levels in vegetables and surface waters at the Central Rift Valley (CRV) of Ethiopia
No full textSeven pesticides, profenofos, metalaxyl, λ-cyhalothrin, 4,4′-DDT, 4,4′-DDE, and α- and β-endosulfan, were determined in vegetables (tomato, onion) from 20 locations and surface waters from 12 locations in the Central Rift Valley (CRV) of Ethiopia. Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) and solid phase extraction (SPE) methods were used for the vegetables and water, respectively. In 2.5% of the tomato samples, profenofos was detected above European maximum residue limits (MRLs), in 12.5% of the samples metalaxyl, and in 2.5% α- and β-endosulfan. In 5% of the onion samples, profenofos was detected above European MRLs, in 7.5% of the onion samples metalaxyl, and in 5% λ-cyhalothrin. In surface water, profenofos was detected at the highest concentration of 2300 μg/L in the Bulbula River, 890 μg/L near the agricultural land north of Lake Ziway (ANLZ-1), 1700 μg/L in the floriculture effluent (FE-1), and 900 μg/L in tap water at the Batu Drinking Water (BDW) supply. These results show that the levels of pesticides are in several cases substantially elevated, and emphasize the need of regular pesticide monitoring programs for surface waters and vegetables in the Ethiopian CRV
S71 | CECSCREEN | HBM4EU CECscreen: Screening List for Chemicals of Emerging Concern Plus Metadata and Predicted Phase 1 Metabolites
No full textAbstract: This is the collection associated with list S71 CECSCREEN HBM4EU CECscreen: Screening List for Chemicals of Emerging Concern Plus Metadata and Predicted Phase 1 Metabolites on the NORMAN Suspect List Exchange. https://www.norman-network.com/nds/SLE/ CECScreen is part of the HBM4EU project (coord. UBA) > WP16 "emerging chemicals" (lead INRA, JP Antignac/L Debrauwer) > Task 16.1 (lead IRAS, J Vlanderen / R Vermeulen) > Main contributor (J Meijer) > Involved Partners (M Lamoree, T Hamers, S Hutinet, A, Covaci, C Huber, M Krauss, DI Walker, EL Schymanski). Further details in Meijer et al (2021) DOI: 10.1016/j.envint.2021.106511. Dataset DOI: 10.5281/zenodo.3956586. Update 23/7/2020 (v0.1.1): updated MetFrag files to remove elements causing errors (Os, Pd, Ag, Be)
Innovations in analytical methods to assess the occurrence of microplastics in soil
No full textThe occurrence of microplastics (MPs, particles <5 mm) in the environment has raised concerns globally due to their extensive use, slow degradation, low recycling rates, and potential risks to the ecosystem and human health. In the last decade, research on MPs in soil ecosystems has increased but is relatively limited compared to studies on MPs in aquatic environments. The soil matrix complexity and the ubiquitous presence of MPs in the environment make the analytical method development, validation, and Quality Assurance/ Quality Control (QA/QC) procedures challenging to analyze MPs in soil. This review paper comprehensively summarizes the emerging techniques and state-of-the-art methods for extracting, analyzing, and characterizing MPs in soil. The choice in analytical technique ultimately relies on the research objectives, whether polymer type, morphological information, quantity, or the presence of MPs in soil is of interest. Among the reviewed studies, globally, a broad range of concentrations (up to 6.9 × 105 particles/kg) of MPs was observed. However, the data was mainly limited to China. Lastly, the validation of analytical methods, QA/QC procedures, and recommendations for future research are addressed. There are no standardized methods to analyze MPs in soil and validate analytical processes, making it difficult to compare methods and results among studies, resulting in large differences in reported results between laboratories participating in interlaboratory studies. This indicates a need to improve and further develop more robust and efficient analytical techniques for analyzing MPs in soil, conduct more interlaboratory studies, manufacture and use certified reference materials, and promote large-scale monitoring research globally. </p
Review of the analysis of insecticide residues and their levels in different matrices in Ghana
No full textThis review reports on how Ghanaian scientists analyse insecticide residues in various matrices in their laboratories as well as the levels of insecticides found in Ghana. It covers different sample preparation methods such as solid-liquid and liquid-liquid extraction. The main technique used for this analysis was gas chromatography (GC) with various detectors such as electron capture, flame photometric, nitrogen phosphorus, and mass spectrometric detection. Liquid chromatography (LC) with mass spectrometric detection was sometimes used to determine the levels of very polar insecticide residues. From the articles reviewed 74% of the insecticides detected were organochlorines with DDTs, lindanes, and endosulfans as most abundant ones. Levels of the insecticides of interest analysed, varied from below the detection limits to clearly above the safety limits. The lowest detected concentration of insecticide residues reported in fruits and vegetables was δ-lindane in pawpaw (0.06 mg/kg) while the highest was fenvalerate (25.6 mg/kg). Insecticide residues reported in sediment were predominantly organochlorines with concentrations ranging from 9.68 ng/kg to 10.98 µg/kg. Endosulfan and its metabolites were the main insecticides found in water bodies with concentrations ranging from 0.036 µg/L to 62.3 µg/L. DDT and its metabolites were the dominant insecticides found in human fluids
Import, disposal, and health impacts of pesticides in the East Africa Rift(EAR) zone: A review on management and policy analysis
No full textEast Africa Rift (EAR) zone countries, such as Ethiopia, Tanzania, Kenya, and Uganda are among the least developed countries in the world. Agricultural activities are the main source of their economy and huge amounts of pesticides have been imported for decades to protect crops from damage by pests and diseases. Some of these pesticides expired in storage before they were used and their disposal became a major problem. Further, these countries declare different policies related to pesticide management. This study reviews the relevant literature about import, disposal and health impacts of pesticides together with different related policies. Web of Science, Google Scholar, and Google were used as the main sources of information. Records show the increases in the import of pesticides in Ethiopia from 2013 to 2016, in Tanzania from 2006 to 2011, in Kenya from 2008 to 2015, and in Uganda from 1980 to 2004. Disposing of obsolete pesticides is very costly and needs proper facilities. Therefore, EAR countries transport these pesticides to European countries for incineration. For example, Ethiopia disposed of 1574.5 and 926 tonnes of obsolete pesticides in collaboration with the FAO. Acute and passive pesticide poisoning occurrences are also discussed in the review. The paper also highlights the policies so far stated. However, these policies lack proper implementation. Therefore, this study suggests EAR countries should use alternative methods to protect crops from the damage caused by pests and diseases, which could reduce the excessive import of pesticides. Similarly, training should also be given to all stakeholders to ensure implementation of all policies
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