New study reveals disturbing information about how clean your pint glass really is

Food for thought the next time you’re out for a pint.

A new study by researchers at the University of Plymouth has revealed that enamelled drinking glasses can potentially contain toxic levels of lead and a soft metal called cadmium. Researchers at the university carried out 197 tests on 72 new and second-hand drinking glass products, including tumblers, beer and wine glasses, and jars and found lead present in 139 cases and cadmium present in 134. Traces of lead and cadmium were found both on the surface of the glasses and, in some cases, on the rims, with concentrations of lead sometimes more than 1000 times higher than the limit level. The tests also showed that flakes of paint often came away from the glass when simulating sustained use, indicating the substances could be ingested over a prolonged period. The study follows a similar one that highlighted the dangers posed by playground paints to public health and the doctor who led both studies, Dr Andrew Turner, believes the threats posed by drinking glasses could be even greater. “The presence of hazardous elements in both the paint and glaze of decorated glassware has obvious implications for both human health and the environment,” Turner said. “So it was a real surprise to find such high levels of lead and cadmium, both on the outside of the glassware and around the rim. There are genuine health risks posed through ingesting such levels of the substances over a prolonged period, so this is clearly an issue that the international glassware industry needs to take action on as a matter of urgency.” The study, published in Science of the Total Environment, analysed a range of glassware using portable x-ray fluorescence (XRF) spectrometry. More than 70% of the products (52 out of 72) tested positive for lead, and the metal was found in all recorded colours, including the decorated gold leaf of some items. A similar number (51 out of 72) tested positive for cadmium, with the highest concentrations usually encountered in red enamel. The lead concentrations ranged from about 40 to 400,000 parts per million (ppm), while quantities of cadmium ranged from about 300 to 70,000 ppm. According to the US Office of Environmental Health Hazard Assessment, the limit levels for the externally decorated lip area of drinking glass are 200 ppm and 800 ppm respectively. Although organic inks that proved negative for lead and cadmium are available, Dr Turner said that the research also showed that hazardous elements are being used to decorate a wider range of consumer glassware that has the potential to be in contact with food, including the exteriors of bottles for the storage of beer, wine or spirits, the external text and logos on egg cups, jugs and measuring cups, and the undersides of coasters and chopping boards. “Given that safer alternatives are available to the industry, the overall results of this study are both surprising and concerning,” Dr Turner added. “Why are harmful or restricted elements still being employed so commonly to decorate contemporary glassware manufactured in China, the European Union and elsewhere? I believe consumers should be made aware of this, while retailers and the glass industry have the responsibility to eliminate toxic metals from decorated products.” For a few more tips on how to tell if your pint glass is clean, this guide will come in handy.