Tenover, brought up a good point on cinder block and "tapcons" which allows you to tap into cement and secure / hold something to cement. My suggestion would be to use a 2 x 4 instead as I would have suggested first, thinking that you would have a wood backing for the 1 x 2 which was earlier suggested.
I don't think the 1 x 2 will give you enough purchase for the PVC in "depth", making it more wobbly if more than one surfboard is placed into a slot using the 1 x 2. Using a 2 x 4, will give you deeper depth in pushing the PVC deeper into the 2 x 4 and glueing to secure the PVC.
Heck, you can measure, predrill your holes all the way through, hang and tapcon into your cement wall, glue the PVC ends and tap them into the 2 x 4 all the way in against the cement wall backing.
Tapcon screws come in different lengths. Expansion bolts can be used too. Use a good 2 part glue for either. Food for thought ~
edit: Counter sink the tapcons or expansion bolts to save your rails on your boards.