"It is in a water course and any pollutants will affect whatever lives in the reens.
"The reason given was that they are only responsible for some reens, not all.
"They proclaim to be guardians of the environment."
He said that, even if not wholly responsible for the particular reens, "the least they (NRW) could have done is take the stuff out of the watercourse".
"There were open paint containers, two oil jacks (one open), a tub of what looked like used oil, cloths, typewriter, TV, CDs, black bags of god knows what."
Natural Resources Wales said that the reens around Black Rock do not form part of the SSSI (Site of Special Scientific Interest).