Allowable limit of arsenic in sunflower lecithin
from FDA
4) Arsenic (as As ). Not more than 3 parts per million. https://www.accessda...rt=184&showFR=1
You can also try this database
If it's a specific EU-based answer for which you're looking...
The current consolidated version of Regulation (EC) 1881/2006 is available here: https://eur-lex.euro...6R1881-20201014
This only include specific limits for inorganic arsenic for rice, and certain rice-based products.
In the absence of a set limit, I believe the general requirements of Regulation (EEC) 315/93 would typically apply if no other limits are set: https://eur-lex.euro...elex:31993R0315
However, despite your supplier's reference to 1881/2006, I suspect that this is potentially used as an additive (i.e. under E number 322)? If that is the case then they should perhaps actually be referring to Regulation (EU) 231/2012, setting the specifications for additives covered by Annexes II/III of Regulation (EC) 1333/2008. This sets a limit of 3mg/kg for Arsenic in Lecithins in general (i.e. not specific to those derived from sunflower). See https://eur-lex.euro...elex:32012R0231
In your position I'd ask your supplier exactly what they mean by their compliance statement, and for confirmation of the specific numerical limit with which their product complies ;)