In the first installment of our interpretation of the updates to Regulation (EU) No 10/2011 on plastic materials and articles intended to come into contact with food, our Technical Services Manager, Eric Andrews, focused his attention on Primary Aromatic Amines (PAA).

As promised, in part two of this series, Eric will cover the Regulations regarding metals and how it encompasses a large amount of data, and will focus specifically on how these changes relate to chromium.

Chromium has been a popular topic for many years which is why these updates are of significant importance.

Eric Andrew’s Interpretation of Metals Updates

The bold content signifies the regulation while the red italicised copy is Eric’s interpretation.

(17) The Authority also adopted an opinion on the risks to public health related to the presence of chromium in food and drinking water(12). In this opinion, the Authority acknowledged that there is a lack of data on the presence of hexavalent chromium in food and decided to consider that essentially all of chromium analytically identified in food is likely to be trivalent chromium as food is, largely, a reducing medium that would not favour oxidation of trivalent chromium to hexavalent chromium. Chromium has been a hot button topic as long as I’ve been in the field, and it certainly predates me. People often stagger when proclaiming which version – hexavalent or trivalent – is more toxic. Part of the confusion is due to the fact that hexavalent chromium often occurs in the form of chromium trioxide – not exactly a misnomer, but a name that inspires one to think, “tri,” nonetheless. Hexavalent chromium (Cr(VI) compounds are noted to be associated with lung cancer and are markedly strong oxidizers. Due in part to this, Cr(VI) compounds readily dissolve in water, and, if ingested, are capable of crossing bodily membranes. Cr(III) compounds are significantly less soluble in aqueous systems and are considered to pose less risk due to their inherent hazard, inversely. In this amendment, the Commission asserts that research has shown the vast majority of total chromium present in food is in the trivalent form – “essentially all,” they state. The Authority added however that, even if a small proportion of the total chromium in food is in the more toxic hexavalent form, it could contribute substantially to hexavalent chromium exposure. Here, they’re not disregarding hexavalent chromium, however. Hexavalent chromium can be present in drinking water including bottled drinking water. Although the more advanced available analytical techniques can distinguish between the trivalent and hexavalent chromium species, this species analytical differentiation can be cumbersome and difficult for competent authorities and business operators. Typically, one will approach the quantification of both valence-forms of chromium by first quantifying total chromium, followed by a more challenging hexavalent chromium quantification step. Trivalent chromium can be derived by subtracting the hexavalent quantity from the total. As the Commission has written; this is cumbersome, requires several steps and is subject to mathematical error. It is therefore appropriate to take into account these considerations when ensuring compliance of plastic materials and articles, intended to come into contact with food that may contain chromium, with the Regulation.

(18) The Authority established a TDI of 0,3 mg/kg body weight per day for trivalent chromium for diffuse duodenal epithelial hyperplasia and haematotoxicity. Through research, the Commission has arrived at a TDI for trivalent chromium! This will serve as a checkpoint for systems containing chromium with a definitive numerical requirement. The Authority estimated that the dietary intakes of trivalent chromium for average and high level consumers in Europe amount to 5 and 8 % of the TDI respectively. This is good news that the Commission can discern that typical consumption of products containing trivalent chromium coming into contact with food is on the very low end of tolerable daily intake. Based on the TDI and on a 20 % allocation factor to account for the contribution of exposure to chromium from sources other than plastic materials and articles intended to come into contact with food and taking into account conventional exposure assumptions for food contact materials, a specific migration limit of 3,6 mg trivalent chromium/kg food or food simulant is appropriate. And here is the hard number. One need only show that one’s EDI for their product is below this published TDI to conclude that the product in question is not risky for the conditions of use declared. It is therefore appropriate to amend Annex II of the Regulation to include trivalent chromium provided that the migration from plastic materials and articles intended to come into contact with food does not exceed 3,6 mg trivalent chromium/kg food or food simulant.

(19) In addition, the Authority also established a benchmark dose (at 90 % confidence limit) (‘BMDL10’) of 1,0 mg/kg body weight per day for hexavalent chromium. Since this species of chromium is genotoxic and carcinogenic, the Authority considered that a Margin of Exposure (‘MOE’) above 10 000 is required for the exposure to be of low concern. Taking into account the BMDL10, the minimum MOE of 10 000, a 20 % allocation to account for the contribution of exposure to hexavalent chromium from sources other than plastic materials and articles intended to come into contact with food, and taking into account conventional exposure assumptions for food contact materials, the migration of hexavalent chromium from plastic materials and articles intended to come into contact with foods should not exceed the level of 0,0012 mg hexavalent chromium/kg food or food simulant to exclude adverse health effects. In this important point and as a callback to the second sentence in item (17), the abundance of hexavalent chromium is anticipated to be significantly lower than the trivalent form, but is considerably more hazardous. In keeping with the dose-makes-the-poison risk assessment ethos so widely accepted, the risk presented from such a species can be lowered by ensuring considerably decreased exposure which is reflected in this final figure. However, according to the EURL-FCM reliable detection of total chromium in food or food simulant has not been tested among National Reference Laboratories below the limit of detection as laid down in Article 11(4) to the Regulation. Therefore it advised to retain the detection limit for chromium of 0,01 mg/kg food instead. As is mentioned, here, there remains testing to be done to validate the assumptions about hexavalent chromium – so we’re to hold onto this final figure for the time being.

(20) There is a large difference in toxicity between trivalent and hexavalent chromium and it is difficult to distinguish between the two chromium species without using burdensome analytical methods. Therefore, verifying compliance with the Regulation of plastic materials and articles that may contain chromium should be done on the basis of hexavalent Chromium as this is the most toxic species. We’re recommended to base risk assessment on the worst culprit and worst-case scenario and so despite everything that’s just been covered, here in the verbiage, we’re snapping right back to where we were. Annex II of the Regulation should therefore be amended to include the detection limit as the limit for chromium migration into food or food simulant. The migration of all chromium, regardless of its oxidation state, from plastic materials and articles intended to come into contact with foods, should therefore not be detectable in food or food simulant above the level of 0,01 mg/kg food or food simulant. Due to outstanding research that remains to be done on hexavalent chromium specifically, we no longer have the advantage of utilizing the 3.6 mg/kg food so painstakingly established quite yet.However, if the business operator placing the material on the market can prove on the basis of pre- existing documentary evidence that the presence of hexavalent chromium in the material can be excluded because it is not used or formed during the entire production process, the migrating species should be considered trivalent chromium only and therefore a migration limit of 3,6 mg/kg food should apply in accordance with the second subparagraph of Article 11(4) of the Regulation. If the business operator can prove that hexavalent chromium is not present whatsoever, such that it’s reasonable to conclude it doesn’t need to be considered as part of risk-assessment, then the more forgiving 3.6 mg/kg food TDI hard figure can be taken advantage of. It is therefore appropriate to amend Annex II to the Regulation. Effectively one half of this story has been fleshed out in having completed the research on trivalent chromium. Until such a time that hexavalent chromium research is completed in the same way in National Reference Laboratories, we’re committed to using numbers we’re likely already familiar seeing – however, there’s been an established opportunity for certain products containing only trivalent chromium to be placed on the market according to the great deal of research that’s been completed on it as part of this amendment.

Please contact Kelly Schaefer if you’re interested in learning more about how our team at CSS can help address and manage these changes for your business.

(12)EFSA Journal 2014;12(3):3595.