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.     

Experimental determination of pesticide processing factors during extraction of seed oils

ABSTRACT

Processing Factors (PFs) reflect the concentration or dilution of pesticide residues resulting from food processing. PFs are key elements to demonstrate the compliance of processed foods with Maximum residue levels (MRLs) as set by Regulation 396/2005. While efforts have been made by the European Food Safety Authority (EFSA) and by national authorities to compile PFs from processing studies, such PFs are not available for all pesticides/processed product combinations. The EU vegetable oil and proteinmeal industry association (FEDIOL) has therefore developed a theoretical approach to approximate MRLs in crude vegetable oils and fats, based on the partition coefficient (log P_ow) of the pesticides and on the oil content of the raw materials. To substantiate this approach, a pilot-scale processing study was initiated with rapeseeds spiked with selected pesticides and the experimental PFs for these pesticides determined. The aims of this study were (i) to study the reliability of pilot-scale conditions for PF determination and (ii) to assess the experimental PFs obtained in comparison to the theoretical PFs proposed by FEDIOL. This study demonstrated that production yields obtained for crude oil and meal in this processing study are similar to those in industrial processes even if differences were observed in the individual production steps (mechanical or solvent extraction steps). The experimental PFs obtained confirmed that the chosen fat-soluble pesticides did concentrate in the oil fraction. For metalaxyl-M having a log P_ow lower than 3, a partitioning between the oil and the meal was observed, as expected. By comparing the experimental PFs and theoretical PFs, it can be concluded that the FEDIOL approach can be recommended as a suitable tool when PFs derived from specific processing studies are missing. Similar studies on pesticides with wider ranges of log P_ow are required in order to complete our conclusions on default PFs for vegetable oils.     

QuEChERS-高效液相色谱法测定食品中4种氨基甲酸酯类农药残留

结合QuEChERS前处理方法,建立了采用高效液相色谱法（HPLC）测定食品中4种氨基甲酸酯类农药残留的方法。以乙腈作为提取溶剂,无水硫酸镁、PSA和GCB净化,C18柱为色谱分离柱,甲醇-水为流动相,检测波长范围190～300 nm进行检测。结果表明,4种农药在6.5 min内实现了基线分离,线性相关系数（R2）≥0.999 8,检出限为2～5 μg/kg,样品加标平均回收率为82.5%～99.3%,精密度试验结果相对标准偏差（RSD）为1.64%～3.30%。该方法操作简单,灵敏度高,结果准确可靠。     

Assessment of PCDD/F,PCB, OCP and BPA dietary exposure of non-breast-fed European infants

The aim of this study is to obtain data on the exposure of non-breast-fed infants to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), polychlorinated biphenyls (PCB), organochlorine pesticides (OCP), and bisphenol A (BPA) and its chlorinated derivatives through consumption of commercial infant foods with largest shares of the market in 22 European Union countries. The E-Screen bioassay was employed to assess the oestrogenicity of the baby foods and the ethoxyresorufin-O-deethylase (EROD) induction was measured to determine the levels of PCDD/F and PCB. Consequently, the highest total effective xenoestrogen burden (TEXB) of 73.60?pM?Eeq?g^?1 was found in the soy-based formula and the EROD bioassay was always below the limit of quantification (LOQ) (3.5?pg?g^?1). Overall, the estimated dietary exposure to BPA via commercial baby foods was lower than the tolerable daily intake (TDI) of 50?µg?kg^?1 body weight (bw). Furthermore, the findings indicated that the dietary exposure of 0–9-month-old infants through the products investigated here does not exceed the maximum TDI of 4?pg WHO-TEQ (toxic equivalents)?kg^?1 bw. However, exposure to more than 2?pg WHO-TEQ?kg^?1?bw?day^?1 might occur for 0–4-month-old infants consuming ‘starting’ hypoallergenic formula. Moreover, analysis of OCP indicated that the dietary exposure of non-breast-fed infants was not harmful. Considering the importance of early development and the vulnerability of infants and children, it is essential to determine their dietary exposure to contaminants in order to decide which efforts of risk reduction should receive highest priority.     

Multi-residue method for the analysis of pesticides in Arabica coffee using liquid chromatography/tandem mass spectrometry

Coffee is a major tropical agricultural commodity and represents a significant fraction of the economy of many countries. However, certain plant and animal species can damage coffee crops, affecting trade. A solution to this issue is the use of pesticides, some of which are harmful to human health and the environment. This work consisted of the development of a multi-residue method for the analysis of pesticides in coffee by using LC-MS/MS. The QuEChERS extraction procedure was used. The following analytical parameters were optimised: selectivity, analytical range, linearity, LOD, LOQ, precision (RSD%) and recovery of the method. The results showed that the method is selective, as they were linear in the range of 10.0–100.0 µg kg^?1. The sensitivity, recovery and precision were adequate for the multi-residue analysis of pesticides in coffee. The method was applied to the analyses of 15 Brazilian coffee samples.     

Dietary exposure of Hong Kong adults to pesticide residues: results of the first Hong Kong total diet study

The use of pesticides and other chemicals has become a common practice in modern agriculture to enhance and stabilise crop yield, protect the nutritional integrity of food, facilitate food storage to assure year-round supplies, and provide attractive and appealing food products. With the adoption of strict good agricultural practice (GAP), only minimal amounts of pesticide residues should remain on the crops or in connected foods of animal origin up the food chain. To assess their associated health risk to local people, the dietary exposure of Hong Kong adults to residues of four groups of pesticides or their metabolites – organophosphorus pesticides (OPPs), carbamates, pyrethrins and pyrethroids, and dithiocarbamate (DTC) metabolites – is estimated in the first Hong Kong Total Diet Study (TDS). A total of 150 commonly consumed food items were collected and prepared “as consumed”. A total of 600 composite food samples were analysed for 85 pesticides or their metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These pesticides were primarily found at low levels (highest mean = 350 μg kg^?1) in food samples of plant origin such as vegetables and fruits. Dietary exposures to pesticide residues were estimated based on the analytical results and the food consumption data of the local residents. The estimated dietary exposures of Hong Kong adults to all individual pesticides were well below their respective acceptable daily intakes (ADIs). The percentage contributions of the estimated mean and 95th percentile dietary exposures to the ADIs of individual pesticides were <6% and <24% for the OPPs, <1% for the carbamates and pyrethrins and pyrethroids, and <1% and <4% for the DTC metabolites, respectively. The findings indicate that dietary exposures to all the pesticide residues analysed in this study were unlikely to pose unacceptable health risks to the Hong Kong population.     

Determination of multi-class pesticide residue in dietary supplements from grape seed extracts by ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry

A new method was developed and validated for the determination of multi-class pesticide residues in nutraceutical products obtained from grape seed extracts. The extraction procedure was based on QuEChERS methodology using ethyl acetate as solvent and a dispersive solid-phase extraction (dSPE) clean-up stage with C₁₈ was included to minimise matrix effects. Pesticides determination was achieved using ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS); total running time was 11 min. Pesticides were quantified using matrix-matched calibration. The developed method was validated in terms of matrix effect, linearity, selectivity, limits of detection and quantification, trueness, repeatability and inter-day precision at three concentration levels (10, 50, 100 µg kg^?1). Suitable recovery values were obtained for 76% of analysed pesticides at the lowest concentration (10 µg kg^?1). For most of the compounds, relative standard deviation values were lower than 20% and 25% for intra- and inter-day precision, respectively. Finally, 106 pesticides were determined, and the method was applied to seven dietary supplements from grape seed extract, obtaining various positive results for piperonyl butoxide, cyromazine and diniconazole at concentrations ranging from 2.0 to 13.4 µg kg^?1.     

分散固相萃取-超高效液相色谱-串联高分辨质谱法测定新疆苹果中7 种农药残留

为快速得到新疆苹果中痕量农药信息,考察新疆苹果种植过程中常用的7?种农药,并针对这7?种常见农药建立了分散固相萃取-超高效液相色谱-串联高分辨质谱的分析方法,旨在快速筛查出可能的农药并同时定量。结果表明：7?种农药线性关系良好,相关系数均大于0.99。方法检出限为0.003～0.1?mg/kg,定量限为0.02～0.5?mg/kg,平均回收率为95%～119%之间,相对标准偏差小于10%（n＝3）。该方法能够排除假阳性结果,快速高效地完成出口前新疆苹果中多农药残留的分析。     

QuEChERS结合液相色谱-串联质谱法测定食用菌中13种农药残留

目的:建立并应用QuEChERS结合液相色谱-串联质谱法测定食用菌中13种农药残留。方法:样品5.0 g用乙腈-水(4:1)15 mL超声提取,经N-丙基乙二胺(PSA)30.0 mg和无水硫酸镁15.0 mg分散固相萃取吸附剂净化。使用HSS T3色谱柱,0.1%甲酸和乙腈为流动相梯度洗脱。质谱采用电喷雾正离子源和多反应监测模式。结果:13种农药的质量浓度在0.5~200 μg/L范围内与峰面积呈良好的线性关系,检出限(S/N=3)0.03~0.3 μg/kg。加标回收率84.3%~102%,相对标准偏差(n=6)2.8%~6.3%。结论:该方法可用于食用菌中13种农药残留的检测。