A preliminary study of toxicity by bioassay of the wastes of pulp and paper production units

The wastewaters from pulp and paper production units are considered significant pollutants because of their physicochemical characteristics (color, suspended solids, high organic load, chlorinated compounds, tannins, lignins, etc.). The aim of this study is to evaluate the toxicity of two paper mills' wastewaters, one of which recycles paper. The toxicity test of these wastewaters was done with the use of bioindicators, using the microbiotests Thamnotoxkit F, Daphtoxkit FTM pulex and rainbow trouts (Oncorhynchus mykiss). In all the samples, the most important physicochemical parameters were measured (BOD5, COD, pH, total suspended solids, volatile solids, lignins, tannins, phenols, phosphates, nitrates, nitrites, chlorine) in order to correlate them with the results of the toxicity tests. The wastewaters from the recycling paper mill (PM1) proved "toxic" for Daphtoxkit FTM pulex and the fish bioassay, while the wastewaters from the paper mill (PM2) were "non toxic" for the trouts and the microbiotest Thamnotoxkit F. Also, according to the results from the biochemical analysis, the wastewaters from PM1 are estimated as more toxic compared to the effluents from PM2.