Ecotoxicity assessment of sludge and leaching test eluates of sludge.
Leaching tests, CEN prEN 12457-2, CEN PrEN 12457-3, and NEN 7349, were conducted for varnish residue and urea resin waste, two industrial wastes containing organic chemicals. The leaching test eluates were analyzed for solvent concentrations and total organic carbon. Aqueous leaching tests were found to be suitable for both chemical and biological testing. Ecotoxicity was assessed by luminescent bacteria, plant root growth, reverse electron transport, and ToxiChromopad. The eluates were highly toxic but the toxicity decreased in later stages of the multistep leaching test (NEN 7349). Urea resin eluates were significantly less toxic than varnish residue eluates. The solid wastes markedly inhibited plant seed germination before and after the leaching test (CEN prEN 12457-3). The solid wastes were not biologically degradable in the standard test (ISO 14593), whereas the eluates from the CEN prEN 12457-3 test degraded slowly.