Confirmation of in situ exposure of fish to secondary treated bleached‐kraft mill effluent using a laboratory simulation

Abstract

Abstract-To corroborate the responses in whitefish (Coregonus lavaretus L.) exposed to elemental chlorine free (ECF) bleachedkraft pulp mill effluent (BKME) in situ, a 30-d laboratory exposure was carried out at concentrations simulating the field conditions. The flow-through exposures were conducted at four secondary (activated sludge) treated effluent (STE) concentrations: 1.3, 2.3, 3.5, and 7%. To evaluate the role of the secondary treatment, fish were also exposed to one concentration (3.5%) of pretreated effluent (PTE) from the mill. Compared to the control, whitefish liver 7-ethoxyresorufin-O-deethylase (EROD) activity was twofold in fish exposed to 3.5% STE, which was similar to monooxygenase induction in the field at the same effluent dilution. The exposure to 3.5% PTE caused a 12-fold relative induction in whitefish. The activity of pentoxyresorufin dealkylase showed a high correlation with EROD activity (r 2 ϭ 0.85, p Ͻ 0.01). The plasma concentration of 17␤-estradiol was reduced by 37% (p Ͻ 0.05) in fish exposed to 3.5% STE, whereas testosterone was reduced by about 40% (p Ͻ 0.05) in fish in both 3.5% STE and PTE groups. The accumulation of chlorophenolics (CPs) and resin acids (RAs) in the bile of the fish was negligible at the three lowest STE concentrations, reflecting the nearly nondetectable levels of CPs and RAs in secondary treated whole effluent. The measured blood parameters plasma immunoglobulin M, glucose, hemoglobin, and hematocrit were not affected by effluent exposure. The responses obtained from the laboratory simulation well accorded with the exposures in the field, although signs of reproductive impairment could be detected in the laboratory. Overall, however, it is evident that the improvements to mill processes and wastewater treatment have substantially reduced the load of harmful constituents in bleached-kraft mill effluent and biological impacts in the receiving environment.

Endocrine Responses of Fundulus Heteroclitus to Effluent From a Bleached-Kraft Pulp Mill Before and After Installation of Reverse Osmosis Treatment of a Waste Stream

“…However, after the industry adopted elemental chlorine-free and totally chlorine-free bleaching processes and installed secondary effluent treatment, reproductive effects in wild and laboratory fish continued to be reported [5,6]. Fish exposed to BKPME in the field and in the laboratory had reduced gonad size, decreased fecundity, altered expression of secondary sex characteristics, increased age at reproductive maturation, and depressed plasma and gonadal production of reproductive steroid hormones [14][15][16][17]19,20,35]. Exposure to environmentally relevant concentrations of BKPME resulted in significant depressions in plasma testosterone levels in both sexes of perch [13], white sucker [14,35], and juvenile whitefish [17].…”

“…Fish exposed to BKPME in the field and in the laboratory had reduced gonad size, decreased fecundity, altered expression of secondary sex characteristics, increased age at reproductive maturation, and depressed plasma and gonadal production of reproductive steroid hormones [14][15][16][17]19,20,35]. Exposure to environmentally relevant concentrations of BKPME resulted in significant depressions in plasma testosterone levels in both sexes of perch [13], white sucker [14,35], and juvenile whitefish [17]. Testosterone is the dominant androgenic hormone in fish and serves as a precursor for other sex steroids such as 11-ketotestosterone in males and 17␤-estradiol in females; the former functions in expression of secondary sexual characteristics and the latter in the synthesis of yolk proteins for developing follicles [35].…”

“…In addition, recent studies suggest that, despite improvements in final effluent quality with changes in the bleaching process and installation of secondary effluent treatment, residual sublethal responses continue to be reported for wild fish exposed to final effluents. Sublethal responses include increased liver size [13][14][15], induction of mixed function oxygenase enzymes [13,14,16,17], and alteration of reproductive and endocrine function, including decreased gonad and egg size, delayed sexual maturation, and depression of reproductive steroid hormone levels [13][14][15][17][18][19][20]. These effects are not unique to a particular bleaching technology, which suggests they originate from the discharge of natural wood organics on the pulping side of mill operations [3,7,14,18,[21][22][23].…”

Bioavailability to Juvenile Rainbow Trout (Oncorynchus Mykiss) of Retene and Other Mixed-Function Oxygenase-Active Compounds From Sediments

“…They were fed ad libitum with Trout Grower 3 PT (Martin Mills Profishnet Feed, Tavistock, ON, Canada) three times a week until 3 d before the start of exposures [12]. For ip injections, trout of similar size were obtained from the Laukaa Fish Culture Research Station (Central Finland) and held under similar conditions in dechlorinated City of Jyväskylä water [15].…”

Attenuated Carbohydrate and Gill Na+ , K+-ATPase Stress Responses in Whitefish Caged near Bleached Kraft Mill Discharges

“…The applied experimental regimens and the areal distribution, based on previous "eld investigations considering the fate of BKME-derived substances (Soimasuo et al, 1998b;LeppaK nen et al, 1999), allowed comparisons between studies of two consecutive years. Previous laboratory studies had found that the BKMEs involved in the present study a!ect, without changeable environmental factors, the physiology of white"sh in several ways (Soimasuo et al, 1998a). These include modi"ed responses of liver and red blood cells to acute handling disturbance (Lappivaara, 2000).…”