TABLE OF CONTENTS

Executive Sumary

1. INTRODUCTION
1.1 Scope and Objectives
1.2 Review Framework

2. CHARACTERIZATION OF POTENTIALLY HAZARDOUS SUBSTANCES
2.1 Factors Influencing The Production Of Organic Substances In Pulp Mill Effluent
2.1.1 Influence of feedstock
2.1.2 Other controlling factors
2.2 Naturally-occuring Organochlorines In Softwood And The Environment
2.3 Progress In The Chemical Characterization Of Pulp Mill Effluent

2.3.1 Products produced by processes other than bleaching
2.3.2 Products produced during bleaching

2.4 Nature Of Substances Discharged In Final, Treated Effluent

3. ENVIRONMENTAL FATE PROCESSES

3.1 Physicochemical Properties Of Pulping/ClO₂ Bleaching Byproducts
3.2 Environmental Behavior Including Redistribution And Partitioning
3.3 Release Of Naturally Occuring Substances From Wood
3.4 Degradation And Persistence

3.4.1 Photolytic destruction
3.4.2 Biodegradation
3.4.3 Metabolic modification and excretion
3.4.4 Sedimentation and burial

3.5 Temporal Trends In Dioxins/Furans In The Receiving Environment

4. EFFECTS CHARACTERIZATION

4.1 Effects Of Pulp Mill Effluents On Fish

4.1.1 Physiological basis for effects

4.1.1.1 MFO induction
4.1.1.2 Regulation of reproductive steroid hormones
4.1.1.3 Causes of MFO induction

4.2 Relationship Of Effects To Pulping, Bleaching And Effluent Treatment Technology

4.2.1 Field studies
4.2.2 Mesocosm studies
4.2.3 Laboratory studies - effluents from mills

4.2.3.1 MFO induction
4.2.3.2 Chronic toxicity

4.2.4 Laboratory studies - experimental effluents

5. CHARACTERIZATION OF RISK

5.1 Assessment Of Chlorinated Phenolics Substances In Pulp Mill Effluent

6. ECOLOGICAL RELEVANCE

6.1 Responses Of Populations And Communities

6.1.1 Fish
6.1.2 Invertebrates
6.1.3 Plants (algae)

6.2 Suborganismal, Physiological Or Biomarker Responses To Pulp Mill Effluents

6.2.1 Measures of exposure
6.2.2 Measures of response

6.3 Bioaccumulation
6.4 Temporal Trends In Biological Responses To Pulp Mill Effluents
6.5 Implications For Continuing Environmental Management Of Pulp Mill Effluents

7. UNCERTAINTIES

8. LITERATURE CITED

LIST OF TABLES

Table 3.1	Compound previously detected in pulp mill final effluents (before and after treatment) and expected environmental behavior
Table 4-1	Compounds, effluents, and process streams from pulp mills that are associated with specific physiological responses of fish
Table 4-2	Results of chronic toxicity tests using effluents from mills with ECF bleaching
Table 5.1	Toxicity criteria and hazard quotients for chlorinated compounds in mill effluents produced from bleaching processes with 100% chlorine dioxide substitution
Table 5.2	Probabilistic assessment of chlorophenol TEQs exceeding the EPA FW criteria




LIST OF FIGURES

Figure 1	The risk assessment process as proposed for use under CEPA (Environment Canada, 1997)
Figure 2	The process of pulp production under bleaching.
Figure 3	Chlorinated aromatic compounds identified from samples of degraded fulvic acid from both natural and bleached kraft mill effluents.
Figure 4	A reaction of lignin with chlorine dioxide.
Figure 5	New organic substances identified in effluent from ECF bleaching.
Figure 6	The reaction of lignin with ozone.
Figure 7	Diagrammatic representation of exposure pathways in pulp mill effluents.
Figure 8	Sterols and triterpenoids found in pulp mill effluents.
Figure 9	Biotransformation reactions in pulp mill effuents.
Figure 10	Temporal trends in total TCDD/TCDF loads from pulp mill in BC, Canada.
Figure 11	Temporal trends in concentration of TCDD/TCDF reported in mill effluents from BC, Canada.
Figure 12	Changes in liver tissue EROD activity in rainbow trout exposed to 1/400 dilution of effluents from pulp mills and other sources.
Figure 13	Illustration of the tiers of risk assessment.
Figure 14	Distributions of concentration of tetrachloroguaiacol and tetrachlorocatechol from mills using 100% chlorine dioxide substitution compared to the most sensitive toxicity enpoint.
Figure 15	Distribution of concentrations of all chlorinated phenols from mills using 100% chlorine dioxide substitution expressed as pentachlorophenol TEQs and compared to assessment criteria for pentachlorophenol.
APPENDIX 1	Compounds identified since 1993 in effluent from mills employing ECF bleaching




Continue to Section 1