Recently listed Stockholm convention POPs: Analytical methodology, occurrence in food and dietary exposure

In recent years, the Stockholm Convention has listed an additional set of persistent organic pollutants (POPs) for elimination or restricted use/release. Data on the occurrence of these contaminants in food is scarce. Validated analytical methodology was developed to investigate the occurrence of hexachlorobutadiene (HCBD), pentachlorobenzene (PCBz), hexachlorobenzene (HCB) pentachlorophenol (PCP) and polychlorinated naphthalenes (PCNs) in 120 retail foods and 19 total diet study samples. The foods covered the range of commonly consumed dietary items including dairy products, eggs (hen and other species), poultry, meat, fish, vegetables, etc. HCBD showed a low frequency of detection, whereas PCBz, HCB and PCNs occurred in most samples (ranges: <0.01 to 0.19 μg/kg; <0.01 to 3.16 μg/kg and 0.1 to 166 ng ΣPCNs/kg respectively). PCP (<0.01 to 1.9 μg/kg) was detected more frequently in meat products, offal and eggs. Fish, shellfish, eggs from all species, animal fats, meat, offal and meat products showed higher contamination levels, which is normal when investigating lipophilic POPs. These levels of occurrence are similar to more recently reported literature levels but perhaps lower, relative to historic data. This is not unexpected, given the restrictions/limitations on these chemicals within the UK and Western Europe. The estimated human exposure to population groups through dietary intake is correspondingly low and based on current toxicological knowledge, the levels in the examined samples do not suggest a cause for health concern. The data also provide a current baseline for HCBD, PCBz and PCP, and update existing data for PCN and HCB occurrence in foods.

The potential of recycled materials used in agriculture to contaminate food through uptake by livestock

The potential for contaminant uptake from recycled materials used in livestock farming, to animal tissues and organs, was investigated in three practical modular studies involving broiler chickens, laying chickens and pigs. Six types of commercially available recycled materials were used either as bedding material for chickens or as fertilizer for cropland that later housed outdoor reared pigs. The contaminants studied included regulated contaminants e.g. polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, dioxins) and polychlorinated biphenyls (PCBs), but related contaminants such as polybrominated diphenylethers (PBDEs), hexabrominated cyclododecane (HBCDD), polychlorinated naphthalenes (PCNs), polybrominated dioxins (PBDD/Fs) and perfluoroalkyl substances (PFAS) were also investigated. Contaminant occurrence in the recycled materials was verified prior to the studies and the relationship to tissue and egg concentrations in market ready animals was investigated using a weights of evidence approach. Contaminant uptake to animal tissues and eggs was observed in all the studies but the extent varied depending on the species and the recycled material. PCBs, PBDEs, PCDD/Fs, PCNs and PFAS showed the highest potential to transfer, with laying chickens showing the most pronounced effects. PBDD/Fs showed low concentrations in the recycled materials, making it difficult to evaluate potential transfer. Higher resulting occurrence levels in laying chickens relative to broilers suggests that period of contact with the materials may influence the extent of uptake in chickens. Bio-transfer factors (BTFs) estimated for PCDD/F and PCBs showed a greater magnitude for chicken muscle tissue relative to pigs with the highest values observed for PCBs in laying chickens. There were no significant differences between BTFs for the different chicken tissues which contrasted with the high BTF values for pigs liver relative to muscle. The study raises further questions which require investigation such as the effects of repeated or yearly application of recycled materials as fertilizers, and the batch homogeneity/consistency of available recycled materials.

Occurrence and spatial distribution of chemical contaminants in edible fish species collected from UK and proximate marine waters

The occurrence of a range of regulated and emerging organic environmental contaminants was investigated in 182 samples of edible marine fish sampled mainly from UK marine regions, but extending northerly to the coast of Norway and south to the Algarve. These species (sprats, mackerel, turbot, halibut, herring, grey mullet, sea bass, grey mullet, sardines, etc.) are among those considered to be at the highest risk of contamination with regulated contaminants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, dioxins), and polychlorinated biphenyls (PCBs), but the occurrence of polybrominated diphenylethers (PBDEs) and polybrominated biphenyls (PBBs) was also investigated. Sub-sets of samples (50-75) were also analysed for emerging contaminants: polychlorinated naphthalenes (PCNs), polybrominated and mixed halogenated dibenzo-p-dioxins, dibenzofurans and biphenyls (PBDD/Fs, PXDD/Fs and PXBs) and perfluoroalkyl substances (PFAS). Contaminant occurrence varied with species and location, but all measured contaminants were detected, with sprats, sea bass, sardines, mackerel, and herring showing higher tissue concentrations. The concentrations of the different contaminants in the various samples were mapped utilising the GPS coordinate data of the capture locations to visualise spatial distribution levels. In terms of catch location, fish sampled from the coasts of southern Britain, north-western France and the Irish Sea appeared to contain proportionately higher levels of some contaminants - e.g. samples from the Irish Sea tended to show higher PCN concentrations, whereas higher levels of PCBs were observed in some fish sampled off the coasts of northern France. Similarly, samples of mullet from the southeast coast of UK showed much higher concentrations of BDE-99 than the other regions. In terms of occurrence trends, PCDD/F and PCB concentrations show a modest decline over the last decade but where limited background data is available for emerging contaminants, there is no evidence of downward trends.

Spatial analysis of polybrominated diphenylethers (PBDEs) and polybrominated biphenyls (PBBs) in fish collected from UK and proximate marine waters

Some commonly consumed marine fish species are considered to display a higher risk of bio-accumulating organic environmental contaminants such as PBDEs. As part of a study to investigate the spatial distribution of these contaminants, data on polybrominated diphenlyethers (PBDEs) and polybrominated biphenyls (PBBs) were collected and analysed by introducing a web-based resource which enables efficient spatial, species and concentration level representations. Furthermore, hierarchical cluster analyses permits correlations within the data to be predicted. The data provide current information on levels of PBDE and PBB occurrence, allowing identification of locations that show higher contaminant levels. 135 fish samples of various species were analysed from UK marine waters, but encompassing the waters around Norway in the North and to the Algarve in the South. PBDEs were observed in all samples with the majority of measured congeners being detected. The concentrations ranged from 0.087 μg/kg to 8.907 μg/kg whole weight (ww) for the sum of all measured PBDE congeners. PBBs occurred less frequently showing a corresponding range of <0.02 μg/kg to 0.97 μg/kg ww for the sum of seven PBB congeners. Concentrations vary depending on species and locations where landed, e.g. PBBs occurred more frequently and at higher levels in grey mullet from French waters. The high frequency of PBDE occurrence makes it prudent to continue the monitoring of these commonly consumed marine fish species. The web-based resource provides a flexible and efficient tool for assessors and policy-makers to monitor and evaluate levels within caught fish species improving evidenced-based decision processes.

Bromine content and brominated flame retardants in food and animal feed from the UK

Current occurrence data for polybrominated diphenyl ethers (PBDE) and hexa-bromocyclododecane (HBCD) measured in most commonly consumed foods (n = 156) and animal feeds (n = 51) sampled in the UK, demonstrates an ongoing ubiquity of these contaminants in human and animal diets. PBDE concentrations for the sum of 17 measured congeners ranged from 0.02 ng/g to 8.91 ng/g whole weight for food, and 0.11 ng/g to 9.63 ng/g whole weight for animal feeds. The highest concentration ranges, and mean values were detected in fish, processed foods and fish feeds. HBCD diastereomers (alpha-HBCD was the most commonly detected) generally occurred at lower concentrations (from <0.01 ng/g to 10.1 ng/g for food and <0.01 ng/g to 0.66 ng/g for animal feed) and less frequently than PBDEs, but tetrabromobisphenol A which was also measured, was rarely detected. The total bromine content of the samples was also determined in an attempt to use a mass balance approach to investigate some of these samples for the occurrence of novel and emerging BFRs. Although the approach was further refined by measuring organic bromine content, the concentrations of bromine were too high (in most cases by orders of magnitude) to allow use of the approach. A selected sub-set of samples was screened by GC-MS, for the presence of novel/emerging brominated flame retardants (PBT, TBX, PBEB, DBHCTD, HCTBPH and OBTMPI) but these were not detected at the higher limits of detection that result from full scan (GC-MS) screening. This data will contribute to the EU wide risk assessment on these contaminants.

Polychlorinated naphthalenes (PCNs) in Irish foods: Occurrence and human dietary exposure

The concentrations of selected polychlorinated naphthalene (PCN) congeners (PCNs 52, 53, 66/67, 68, 69, 71/72, 73, 74 and 75) were determined in 100 commonly consumed foods, in the first study on occurrence of these contaminants in the Republic of Ireland. Congener selection was based on current knowledge on PCN occurrence and toxicology, and the availability of reliable reference standards. The determinations were carried out using validated analytical methodology based on 13C10 labelled internal standardisation and measurement by HRGC-HRMS. The results showed PCN occurrence in the majority of studied foods--milk, fish, dairy and meat products, eggs, animal fat, shellfish, offal, vegetables, cereal products, etc. ranging from 0.09 ng kg(-1) whole weight for milk to 59.3 ng kg(-1) whole weight for fish, for the sum of the measured PCNs. The most frequently detected congeners were PCNs 66/67, PCN 52, and PCN 73. The highest concentrations were observed in fish, which generally showed congener profiles that reflect some commercial mixtures. The data compares well with other recently reported data for Western Europe. The dioxin-like toxicity (PCN TEQ) associated with these concentrations is lower than that reported for chlorinated dioxins or PCBs in food from Ireland. The dietary exposure of the Irish adult population to PCNs was calculated following a probabilistic approach, using the full dataset of occurrence and current consumption data. The estimates of dietary intakes at approximately 0.14 pg TEQ kg bw(-1) month(-1) for adults on an average diet, reflects the relatively lower occurrence levels.

Effectiveness of dietary advice given by community dietitians to men with elevated blood cholesterol in a clinical setting: a pilot study

OBJECTIVE

To compare the effect of two types of dietary advice given by community dietitians on subsequent dietary intake in Scottish men, over 8 weeks.

DESIGN

A parallel design intervention study was employed. Twenty-five men with elevated blood cholesterol levels were randomly assigned to Group 1 (advice to reduce dietary fat only) or Group 2 (advice to reduce dietary fat and sugar).

RESULTS

Neither group significantly reduced fat intakes, yet both groups self-rated their fat intake as being lower at the end than at the start of the study. Group 2 reduced per cent energy from sugar and increased per cent energy from starch without significantly changing per cent energy from total carbohydrate. No significant change in blood cholesterol levels were observed.

CONCLUSIONS

Advice to reduce dietary fat was not effective in this group of subjects. Advice to reduce both fat and sugar resulted in a decrease in sugar intake only. Both groups wrongly rated their fat intake to be lower at the end of the study. This may be a barrier to further dietary advice.

Case report: obstructive sleep apnea--an air safety risk

Aviation safety reports indicate that many incidents are related to fatigue. Obstructive sleep apnea (OSA) is characterized by irregular snoring with repeated apnea episodes during sleep and excessive daytime sleepiness. Deprived of sleep, patients suffer from daytime sleepiness and involuntary sleep attacks. The prevalence of OSA among adult men is more than one percent, 0.5% in women. Predisposed are men aged 40-65 yr. Many patients, including pilots, are unaware of their sleeping disturbance and the symptoms are not easily recognized. Therefore, this condition may not be discovered during a regular health examination. However, this condition can be effectively treated. In our opinion, pilots suffering from OSA do not necessarily have to lose their certificate. Diagnosis and treatment can be conducted, followed by regular check-ups. We suggest that questions about sleep be included in pilots' health examinations.