J. Tana et al., ASSESSING IMPACTS ON BALTIC COASTAL ECOSYSTEMS WITH MESOCOSM AND FISHBIOMARKER TESTS - A COMPARISON OF NEW AND OLD WOOD PULP BLEACHING TECHNOLOGIES, Science of the total environment, 145(3), 1994, pp. 213-234
This study has taken an advanced ecotoxicological approach to assess t
he effects on the aquatic environment of pulp bleaching effluents (rep
resenting different types of bleaching technology) using land-based mo
del ecosystems which mimic the sublittoral zone of the Baltic Sea. Exp
osure was carried out at realistic, low concentrations over a time per
iod of 4.5 months. The effluent from the conventional or oldest bleach
ing technology was most toxic to invertebrates, causing secondary effe
cts on algal production. However, when assessing the overall effects o
n algae, invertebrates, fish growth and fish physiology caused by the
effluents from newer bleaching technologies, no correlation was observ
ed between concentration of adsorbable organic halogen (AOX) and level
of effect. Nor was there any correlation between the levels of conjug
ated chlorophenolics or resin acids in the bile of rainbow trout and p
hysiological effects in the fish. This lack of relationship between co
ncentration of chlorinated organic substances and biological responses
makes it necessary to search for alternative bioactive compounds. Pos
sible candidates might be plant sterols originating from the pulped wo
od.