Review of science relating to discharges from the Kinleith pulp and paper mill

TR 2005/58
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Report: TR05/58

Authors: Nick Kim and Jeff Smith

Abstract

The Kinleith pulp and paper mill, south of Tokoroa, is operated by Carter Holt Harvey Ltd (CHH). In 1994, CHH's precursor, New Zealand Forest Products Ltd (NZFP) applied to Environment Waikato for an air discharge permit. In 1996, CHH applied for consent for water-related activities. Each application was accompanied by an assessment of environmental effects (AEE) and, in order to characterise the potential impacts of mill discharges, the applicant had commissioned a reasonably comprehensive suite of interlocking scientific investigations and appraisals.

The consent application and its assessment was technically involved, comprising evidence from experts acting on behalf of the applicant, and scientific audit of this evidence and formulation of recommended consent conditions by experts acting on Environment Waikato. After an open hearing, and an appeal, consent was granted by an Environment Court consent order. Consent certificates were last amended in 2003.

A number of safeguards were built in to the consent conditions. A central requirement specified in the two main consent certificates (authorising discharges of contaminants to water and air) is that the consent holder seeks to achieve continuous improvements in discharge quality, as far as practicable.

Although impacts of the discharge to water in Lake Maraetai and downstream were judged to be relatively minor in terms of quantifiable adverse effects on aquatic organisms, the resource consent authorising the main contaminant discharge to water nonetheless requires that further scientific assessments be carried out on the health of the aquatic ecosystems in the receiving environment, to ensure that significant adverse effects are not being induced by the discharge during the consent period. Two rounds of effects assessments are scheduled during the consent period, for 2008 and 2015.

Despite having been subject to technical appraisal and an open consent process, and incorporation of safeguards in the consent conditions, discharges from the Kinleith mill continue to attract a certain amount of public concern. Such concern is likely to have been exacerbated by two recent operational failures experienced at the site - a sludge dam failure in December 2003, and a limited release of chlorine/chlorine dioxide gas to air in June 2004. There is also an awareness that science in the area of assessing the potential effects of pulp and paper mill discharges (particularly to water) has further developed since 1998, the date at which the last significant body of technical evidence was compiled.

As a matter of due diligence, Environment Waikato staff therefore perceived a need to review recent scientific information as it might relate to the Kinleith mill discharges, in order to assess whether there was any external evidence suggesting the existence of significant unmanaged environmental effects, and whether present consent conditions would still be regarded as suitably protective in the context of current scientific understanding. This is the purpose of this review.

Review of Science Relating to Discharges from the Kinleith Pulp and Paper Mill [PDF, 1 MB]

Contents
1 Introduction 1
2 Scope, structure and sources 2
2.1 Prior evidence and assessment - Sources 3
2.2 Developments since the previous evidence was compiled - Sources 3
2.2.1 Review of relevant recent research 3
2.2.2 New or updated guidelines 5
2.2.3 Compliance monitoring information 5
3 Assessments 7
3.1 Overview 7
3.2 Discharge to water: General wastewater quality and quantity 7
3.2.1 Prior evidence and assessment 7
3.2.2 Developments since the previous evidence was compiled 9
3.2.3 Updated assessment 14
3.3 Discharge to water: Constituents of biological relevance: Colour, biological oxygen demand, plant nutrients 14
3.3.1 Prior evidence and assessment 14
3.3.2 Developments since the previous evidence was compiled 15
3.3.3 Updated assessment 16
3.4 Discharge to water: Constituents of biological relevance: Potentially toxic elements and compounds 17
3.4.1 Prior evidence and assessment 17
3.4.2 Developments since the previous evidence was compiled 23
3.4.3 Updated assessment 36
3.5 Discharge to water: Effects assessments 41
3.5.1 Prior evidence and assessment 41
3.5.2 Developments since the previous evidence was compiled 43
3.5.3 Updated assessment 45
3.6 Discharge to water: Human uses and exposure to contaminants 46
3.6.1 Prior evidence and assessment 46
3.6.2 Developments since the previous evidence was compiled 47
3.6.3 Updated assessment 51
3.7 Discharge to air: Characteristics 53
3.7.1 Prior evidence and assessment 53
3.7.2 Developments since the previous evidence was compiled 54
3.7.3 Updated assessment 58
3.8 Discharge to air: Potential effects to workers 59
3.8.1 International evidence and assessment 59
3.8.2 New Zealand epidemiology 61
3.8.3 Assessment 63
4 Summary 64
4.1 Water 64
4.2 Air 66
5 Recommendations 67
5.1 Water 67
5.2 Air 67
6 Appendices 69
6.1 Documents relating to prior evidence and consent assessment 69
6.2 New Zealand pulp and paper related research identified in this review and published since 1998 71
6.3 Potentially relevant guidelines and standards in use since granting of the Kinleith pulp and paper resource consents 74
6.4 Other references 74
6.5 Estimated flows in Kopakorahi Stream and wastewater dilution volumes 79
6.6 Compilation of reported concentrations of trace organic compounds at the point where Kopakorahi Stream enters the arm of Lake Maraetai (site K2). 80