Degradation of 32 emergent contaminants by UV and neutral photo-fenton in domestic wastewater effluent previously treated by activated sludge

This study focuses on the removal of 32 selected micropollutants (pharmaceuticals, corrosion inhibitors and biocides/pesticides) found in an effluent coming from a municipal wastewater treatment plant (MWTP) based on activated sludge. Dissolved organic matter was present, with an initial total organic carbon of 15.9 mg L⁻¹, and a real global quantity of micropollutants of 29.5 μg L⁻¹. The treatments tested on the micropollutants removal were: UV-light emitting at 254 nm (UV₂₅₄) alone, dark Fenton (Fe^2+,3+/H₂O₂) and photo-Fenton (Fe^2+,3+/H₂O₂/light). Different irradiation sources were used for the photo-Fenton experiences: UV₂₅₄ and simulated sunlight. Iron and H₂O₂ concentrations were also changed in photo-Fenton experiences in order to evaluate its influence on the degradation. All the experiments were developed at natural pH, near neutral. Photo-Fenton treatments employing UV₂₅₄, 50 mg L⁻¹ of H₂O₂, with and without adding iron (5 mg L⁻¹ of Fe²⁺ added or 1.48 mg L⁻¹ of total iron already present) gave the best results. Global percentages of micropollutants removal achieved were 98 and a 97% respectively, after 30 min of treatments. As the H₂O₂ concentration increased (10, 25 and 50 mg L⁻¹), best degradations were observed. UV₂₅₄, Fenton, and photo-Fenton under simulated sunlight gave less promising results with lower percentages of removal.The highlight of this paper is to point out the possibility of the micropollutants degradation in spite the presence of DOM in much higher concentrations.     

毛细管气相色谱法测定油炸食品中特丁基对苯二酚的残留量

目的建立毛细管气相色谱法测定油炸食品中特丁基对苯二酚的残留量。方法采用毛细管气相色谱法。色谱柱为HP-5弹性石英毛细管柱(30 m×0.25 mm,0.25μm);载气为氮气;检测器为FID;进样口和检测器温度均为250℃;柱温为220℃,保持15 min。结果特丁基对苯二酚在1.0～100.0mg/L的范围内线性关系良好,r=0.999 7;回收率为90.1%～106.8%(n=3);方法的检测限为0.5 mg/kg。结论本法灵敏度高、简便、易行,结果准确可靠,可为油炸食品的质量控制提供依据。     

Nanofiltration of Hormone Mimicking Trace Organic Contaminants

Abstract

The removal mechanisms of three hormone mimicking organic compounds by nanofiltration (NF) membranes have been examined. Two NF membranes having different pore sizes were used in laboratory‐scale nanofiltration experiments with feed solutions spiked with a hormone mimicking compound—nonylphenol, tert‐butylphenol, or bisphenol A. Retention of the compounds was determined at various solution chemistries, namely aqueous solution pH, ionic strength, and presence of natural organic matter. The nanofiltration behavior of the selected hormone mimicking compounds appears similar to that of natural hormones as reported in our previous work. While the solution pH can dramatically influence the retention of hormone mimicking compounds by a loose NF membrane, ionic strength does not affect the nanofiltration of such contaminants. However, in the presence of natural organic matter in the feed solution, ionic strength appears to play a significant role in solute‐solute and solute‐membrane interactions, resulting in increased retention due to partitioning of the hormone mimicking compounds onto organic matter at a higher ionic strength.     

Optimisation of an analytical method and results from the inter-laboratory comparison of the migration of regulated substances from food packaging into the new mandatory European Union simulant for dry foodstuffs

This paper presents the outcome of the development, optimisation and validation at European Union level of an analytical method for using poly(2,6-diphenyl phenylene oxide – PPPO), which is stipulated in Regulation (EU) No. 10/2011, as food simulant E for testing specific migration from plastics into dry foodstuffs. Two methods for fortifying respectively PPPO and a low-density polyethylene (LDPE) film with surrogate substances that are relevant to food contact were developed. A protocol for cleaning the PPPO and an efficient analytical method were developed for the quantification of butylhydroxytoluene (BHT), benzophenone (BP), diisobutylphthalate (DiBP), bis(2-ethylhexyl) adipate (DEHA) and 1,2-cyclohexanedicarboxylic acid, diisononyl ester (DINCH) from PPPO. A protocol for a migration test from plastics using small migration cells was also developed. The method was validated by an inter-laboratory comparison (ILC) with 16 national reference laboratories for food contact materials in the European Union. This allowed for the first time data to be obtained on the precision and laboratory performance of both migration and quantification. The results showed that the validation ILC was successful even when taking into account the complexity of the exercise. The results showed that the method performance was 7–9% repeatability standard deviation (rSD) for most substances (regardless of concentration), with 12% rSD for the high level of BHT and for DiBP at very low levels. The reproducibility standard deviation results for the 16 European Union laboratories were in the range of 20–30% for the quantification from PPPO (for the three levels of concentrations of the five substances) and 15–40% from migration experiments from the fortified plastic at 60°C for 10 days and subsequent quantification. Considering the lack of data previously available in the literature, this work has demonstrated that the validation of a method is possible both for migration from a film and for quantification into a corresponding simulant for specific migration.     

食品中化学污染物风险评估研究进展

化学污染物是影响全球食品安全和危害人体健康的主要因素之一。对食品中化学污染物进行风险评估是保障食品安全、促进食品贸易和健全食品安全体系的重要手段。本文简要介绍了化学污染物风险评估的内容和基本方法,对国外化学污染物风险评估开展情况进行了概述,重点对国内开展的食品中化学污染物风险评估的研究进展进行综述,包括重金属、有机污染物、农药残留、黄曲霉毒素等,并对国内开展食品中化学污染物风险评估的方法进行了分析比较。重金属、农药残留和黄曲霉毒素方面的评估结果均表明:儿童的膳食暴露量偏高,需引起重视。此外提出目前我国食品中化学污染物风险评估中存在的主要问题和建议,为进一步开展化学污染物风险评估提供借鉴。     

p-Cresol in cheese: Is it a flavouring compound or chemical contaminant?

ABSTRACT

p-Cresol has been identified as a flavouring compound in cheeses; however, scientific studies have already identified p-cresol as a potential chemical contaminant in environmental matrices. Thus, the objective of this study was to evaluate four traditional methods for extracting p-cresol from cheese samples in order to validate the best method, and finally to apply it to five cheese samples with different origins, processing and ripeness times. The analyses were performed by gas chromatography-mass spectrometry after derivatisation of p-cresol with anhydride acetic and pyridine. Better results were achieved by the QuEChERS method, which showed recovery higher than 80%, relative standard deviation lower than 16%, limit of quantification of 5 μg kg^?1 and linearity between 5 and 400 μg kg^?1 with R² 0.99. p-Cresol was quantified in almost all of the samples analysed at different concentration levels, which were in an increasing order at μg kg^?1: Cheddar (< LOQ), Parmesan (8 ± 0.7), Gorgonzola (103 ± 14), smoked Provolone (365 ± 28) and barbecue cheese (1001 ± 187). Although no maximum residue limit has been established for p-cresol in food, the results suggest that cheeses exposed to charcoal combustion notably increase the p-cresol levels and may represent a hazard to human health, especially in risk groups such as patients with chronic kidney disease who have serious problems with p-cresol.     

2017—2019年普洱市食品中化学污染物监测结果分析

目的了解2017—2019年普洱市食品风险监测中化学污染物状况。方法 2017—2019年在普洱市辖区内各区县农贸市场、商店等采集不同种类食品样本进行食品接触材料污染物、食品添加剂、兽药残留、元素、农药残留等项目的检测。结果 2017—2019年普洱市食品超标率分别为食品接触材料污染物32.00%、食品添加剂24.32%、兽药残留3.17%、元素3.03%、农药残留0.73%。结论普洱市常见食品中有部分化学污染物(五氯酚钠、含铝添加剂、铅、砷、强力霉素、恩诺沙星、甲拌磷、甲拌磷砜等)超标,对人体健康造成危害。各相关部门应加强监管。     

Analysis of environmental chemical residues in products of emerging aquaculture industry in Uganda as case study for Sub-Saharan Africa

A study was conducted to analyse market-regulated heavy metals (lead, mercury and cadmium), organochlorine pesticides and total polychlorinated biphenyls (PCBs) in samples of 38 farmed fish comprising Nile tilapia (Oreochromis niloticus) (20 samples) and African catfish (Clarias gariepinus) (18 samples) from ten selected fish farms in Uganda. The goal of this case study was to understand the safety of aquaculture products from Sub-Saharan Africa. Lead was detected in all the 38 samples (maximum = 1.08 mg kg^?1 (dry weight)), mercury in 31 out of 38 samples (maximum = 0.35 mg kg^?1 (dry weight)), and cadmium in two samples (maximum = 0.03 mg kg^?1 (dry weight)). Total levels of PCBs were below the limit of detection of 0.02 mg kg^?1 (wet weight) in all the samples. Traces of 4,4′-dichloro-diphenyldichloroethylene (DDE) were detected in ten out of 38 samples (maximum = 0.01 mg kg^?1 (wet weight)) making it the most prevalent organochlorine pesticide. Other pesticides detected were: 4,4′-dichloro-diphenyl-trichloroethane (DDT) and endosulfan sulphate, which were found in one fish sample (both 0.002 mg kg^?1 (wet weight)). There was no statistically significant difference between the levels of lead and mercury in catfish and tilapia (t-test at p = 0.05). More catfish samples (eight) contained DDE as compared with tilapia (two). Cadmium, DDT and endosufan sulphate were only detected in catfish implying that catfish is more prone to contamination than tilapia. The levels of contaminants were below the US Food and Drug Administration (USFDA) action levels and European Union maximum residue limits (MRLs), indicating that such fish have the potential for export to these markets.     

Furan in canned sardines and other fish

Thirty-seven different samples of canned sardines and other fish sold in the United Kingdom were analysed for their furan content using a validated automated headspace gas chromatography–mass spectrometry procedure. All 37 samples contained detectable furan, with an average level of 26 μg kg^?1. The maximum furan content was in canned fish containing tomato sauce, which had an average of 49 μg kg^?1 and in canned fish packed with lemon which had an average of 55 μg kg^?1. All fish in brine or in oil contained less than 20 μg kg^?1 furan. Furan levels recorded in fish packed in extra virgin olive oil were low with an average of 2 μg kg^?1.     

Comparison of extraction conditions for milk and hen's egg allergens

The evaluation of recovery rates by extracting milk powder and egg powder using eleven different extractants gave approximately similar results for both foods. Compared with the other extraction solutions investigated, ‘1% Tween 20® and 0.4% Triton X-100®’ and ‘4% SDS’ are the most suitable extractants to isolate proteins of hen's egg or milk. When comparing calculated protein recovery rates of egg and milk powder extracts, the results clearly indicated that the choice of a suitable extractant is of particular importance. Qualitative investigation of the extracts via LDS-PAGE followed by silver staining as well as immunoblotting confirmed the results of protein quantification. Hence, the immunoblots showed that the extraction agents had no negative influence on the antigenicity of the extracted allergenic proteins. In this study, variation of extraction temperature led neither to any benefit in extraction quality nor to degradation. Changing pH did not reveal any trends, but progressive protein hydrolysis under strong alkaline conditions. Evaluation of recovery rates as well as results of unspecific and specific staining of the extracts showed that an extraction time of 1?h is sufficient for an appropriate sample preparation. For investigations with and without food matrix different results were obtained. In summary, wheat starch did not influence the extraction quality within all examined materials and different extractants. In contrast, using fat powder and dry cake mix, respectively, led to different results in the extraction procedure. When fat powder and dry cake mix were used as food matrices, some protein recovery rates decreased and some increased depending on the allergen material. These results highlight the fact that the suitability of the extractant not only depends on the properties of the allergen but furthermore on the type of matrix containing the allergen.