Composition of materials used as substrate for biofilm formation (data provided by the suppliers: Novacimnor, Porto, Portugal; Universal AFIR, Porto, Portugal and Neves & Neves, Trofa, Portugal).

Material (US standard)	Surface material composition (%)
	Cu	Fe	Ni	Mn	Sn	Al	Zn	Cr	Other
AISI 316	—	62	10–14	2	—	—	—	16–18	C, Si, P, S, Cr Mo, N
C11000	100	—	—	—					—
C18000	96	—	4	—					—
C90800	87	0.03	—	—	12	—	0.03	—	Pb (0.62), Zn (0.03), P (0.32)
C95500	79	—	5	1		10			—
C38500	57	5	—	—			39		Pb (0.03)