Monday March 1 2010
Antimony is known for its toxic properties
The Daily Express reported that “a poison as harmful as arsenic is contaminating fruit juices and cordials drunk by millions of people every day across Britain”. The newspaper said that the toxic chemical antimony was discovered in 16 popular brands of juice and squash.
This research behind the news measured antimony levels in 42 juice-based drinks including 16 beverages from one brand. They found that most of the juices (34 out of 42) contained levels of antimony within the acceptable limits for European Commission (EC) drinking water, with eight drinks exceeding the threshold. However, all of these eight contained levels below the World Health Organization threshold for drinking water. The researchers did not assess whether the antimony leaked in from the packaging or originated from the drinks themselves.
This study did not look at whether consumption of the juices tested was associated with any adverse health effects. This issue is sure to be investigated further, and if it proves to be an area of concern, it is likely that guideline limits will be set by regulatory authorities. These findings should not currently be a cause for undue concern, but anyone who is concerned should avoid drinking juices past their expiration date and dilute cordials according to instructions on the label.
Where did the story come from?
Claus Hansen and colleagues from the universities of Copenhagen and Crete carried out this research. No specific sources of funding for the study were reported, although one author had received funding from the Royal Society of Chemistry in the UK. The study was published in the peer-reviewed Journal of Environmental Monitoring.
The Daily Express and Daily Mail reported on this research. The Mail did not point out that only eight of the 42 drinks tested contained antimony amounts greater than the EC guidelines. Also, neither newspaper reported that none of the drinks exceeded the threshold levels for drinking water set by the WHO.
What kind of research was this?
This was a laboratory study looking at the levels of a substance called antimony in various commercially available fruit juice drinks. Antimony is a chemical element with no known biological function in the body.
The authors of the study report that a compound called antimony trioxide is suspected to be a human carcinogen (a substance known to exacerbate cancer), and that it is listed as a “priority pollutant” by the US Environmental Pollution Agency (EPA) and the EC.
Antimony trioxide is used in the production of polyethylene terephthalate (PET) plastics, and the authors report that recent studies observed that antimony leaches into drinks that are contained in PET bottles. They say that levels of up to 2.57 microgrammes per litre had been found in this earlier research, a level within the safe limits for drinking water set by the Commission of the European Communities (5 microgrammes per litre). Higher thresholds are set by the USA EPA (6 microgrammes per litre) and WHO (20 microgrammes per litre).
This was a cross-sectional study, the type of research appropriate for measuring the concentrations of various chemicals in foodstuffs at one point in time. The study did not look at the health effects of drinking these juice-based drinks.
What did the research involve?
The researchers tested the concentrations of antimony in a range of fruit-based drinks and measured the levels in them against the guideline limits for antimony in drinking water set by the EC, US EPA, and the WHO. They also looked at whether the levels of antimony varied by type of packaging used for the drinks.
The researchers measured antimony concentrations in 42 drinks samples, representing 28 different products sold by 16 different brands. They looked at blackcurrant, mixed fruit, strawberry, raspberry, sour cherry, mint and synthetic caramel juice drinks, obtained from local groceries in Greece, Denmark and Scotland. The drinks were either ready-to-drink or cordials, which were diluted as instructed on the labels prior to testing. The juices were in PET plastic bottles, glass, and Tetra Pak cartons.
The researchers also tested reference samples containing known concentrations of antimony to ensure that their measurement methods were accurate.
One widely available brand of blackcurrant juice, termed ‘brand A’ for testing, showed particular high antimony concentration in the initial screening. The high levels led the researchers to test 16 samples of nine different ‘brand A’ products obtained from this manufacturer. This included one product that had passed its expiry date.
What were the basic results?
The researchers found that eight drinks had levels of antimony above the safe limits for drinking water set by the EC (5 microgrammes per litre). The highest level identified was in a glass-bottled sour cherry drink available in Greece, which contained 13.6 microgrammes of antimony per litre.
The seven other drink samples with levels exceeding the 5 microgrammes per litre limit all came from brand ‘A’, which was produced in the UK and obtained in Denmark, Greece and Scotland. The cordial from this brand with the highest concentration of antimony was from the sample past its expiration date. Some samples from this brand did not have antimony levels above 5 microgrammes per litre.
Overall, the researchers did not find any obvious relationships between antimony levels and the expiration date, carbohydrate content, pH or percentage of juice in the drink. Among ‘brand A’ juices, there was a relationship between carbohydrate level, expiry date and antimony level, with drinks closer to their expiration date and drinks with higher carbohydrate levels having higher antimony levels.
The researchers were unable to confirm the exact chemical form of the antimony found in the drinks.
How did the researchers interpret the results?
The researchers conclude that “antimony concentrations up to a factor of 2.7 above the EU limit for drinking water were found in commercial juices and may either be leached from the packaging material or introduced during manufacturing, pointing out the need for further research on the area”.
They also say “trends in the data indicate that the [antimony] has leached from the packing material. However, it cannot be excluded that the [antimony] was present prior to packing. Thus, further studies are warranted”.
This study has found that some juice drinks tested (most coming from one brand) had levels above the threshold set by the EU for drinking water. There are several important points to note:
- The EC, US EPA, and the WHO are reported to have set differing guidelines for what level of antimony is permissible in drinking water, ranging from 5 microgrammes per litre to 20 microgrammes per litre. Reportedly, no threshold levels have been set for antimony in foodstuffs.
- Only eight out of the 42 juice drinks tested (19%) had levels greater than the EC threshold for drinking water of 5 microgrammes per litre. Of these eight drinks only two appeared to have concentrations above the US EPA threshold limits for drinking water (6 microgrammes per litre) based on a graph of guideline levels. None of the drinks tested exceeded the WHO’s threshold (20 microgrammes per litre).
- None of the brands were named in the report, and it was unclear exactly how many are available in the UK.
- The current study only assessed a relatively small number of samples (42), and the authors say that a previous study looking at fruit juices showed lower levels than found in this study. Therefore it will be important to verify these findings in further samples.
- The researchers did not assess where the antimony in the drinks came from (ie the packaging or the manufacture of the juice). Equally, the researchers were unable to determine exactly what chemical form the antimony took in the juice. Different forms will vary in their toxicity.
- When considering what risk the antimony levels in drinks could potentially carry, one important factor is exactly how much juice a person may consume. For example, the drinking water concentration guidelines set by the WHO are based on an estimated water intake of two litres of water per day.
This study did not look at whether consumption of the juices tested was associated with any adverse health effects. This issue will no doubt be investigated further, and if it proves to be an area of concern, it is likely that threshold levels will be set by regulatory authorities. These findings should not currently be a cause for undue worry, but anyone who is concerned could try to avoid drinking juices past their expiration date and to dilute cordials according to instructions on the label.