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Summary and Conclusion
Pipes for drinking water of PE are used more and more, and therefore the Danish Environmental
Protection Agency wants to update its knowledge about which additives, including antioxidants, are
currently used in the production of plastic pipes for drinking water, and the extent to which these
additives and their degradation products migrate to drinking water.
The Danish Ministry of Environment, including the Nature Agency in cooperation with the Danish
Environmental Protection Agency, advises the Danish Energy Agency on the standards for drinking
water installations, i.e. limits and test methods for migration of chemical substances from e.g. PE
pipes for drinking water. The updated information in this report will form the basis for the agencies
to identify relevant organic substances for a possible update of the 2007 Danish EPA health
assessment of selected degradation products from plastic pipes for drinking water /3/.
This status assessment evaluates polyethylene (PE) pipes used in the distribution systems and
cross-linked polyethylene (PEX) pipes for water installations in buildings, and is based on the
knowledge already obtained in field studies of PE pipes, see Environmental Project No. 1049/10/
and Environmental Project No. 1167 /11/. These studies include DS certified PE pipes of three pipe
products /10/ and PEX-a and PEX-c pipes /11/. In addition, the report includes the latest
knowledge from Danish and international research projects as well as recent measurements from
the distribution system on the migration of organic substances from PE pipes to drinking water.
International research includes both PEX-a, PEX-b, and PEX-c pipes /6/. The status assessment
evaluates pipe products commonly used in Danish water supply systems and the manufacturers of
these types of pipe are responsible for the delivery of the majority of approved plastic pipes in
Denmark. Other types of pipes, for example, PE-RT for water installations in buildings are
described in Section 2.1.
Annex 1 contains a list of the additives in the base products used for the production of PE and PEX
pipes for which DS certification or VA authorisation have been applied for. In recent years, there
have been no major changes in the antioxidants used in the production of PE pipes. In connection
with the DS certification or the VA authorisation, data on the use of other antioxidants frequently
emerges, but some of these antioxidants are also degraded to the same degradation products as
described in 2007 Danish EPA health assessment /3/ of the substances listed below. Other
degradation products migrating from PE pipes to the drinking water are listed in Appendix 2.
• 2,4-di-tert-butylphenol
• 2,6-di-tert-butyl-p-benzoquinone
• 3-(3,5-di-tert-butyl-4-hydroxyphenyl) methyl propanoate
• 3,5-di-tert-butyl-4-hydroxy benzaldehyde
• 3,5-di-tert-butyl-4-hydroxy acetophenone
• 7,9-di-tert-butyl-1-oxaspiro(4,5)-deca-6,9-diene-2,8-dione
• 5-methyl-2-hexanone
• Ethylphenol
• 4-tert-butylphenol
• 3,5-di-tert-butyl-4-hydroxystyrene
• 4-methyl-2,5-di-tert-butylphenol (BHT)
• 4-butoxyphenol
• Tert-butanol (TBA)
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