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Working Towards a Comprehensive Policy Framework for Managing Contaminated Land in New Zealand: Report on Submissions

Executive summary

1 Introduction

2 Overview of submissions

3 Key elements and work priorities

4 National environmental standards

5 Roles and responsibilities

6 Guidance

7 Liability

8 Accreditation

9 Capability

10 National information

11 Additional research areas

12 Additional opportunities

13 Workshop overview

Appendix A: Index of submitters

Abbreviations

References

4 National environmental standards

The vast majority of submitters partially agreed or conditionally agreed that a guideline progressing to a standard is the most appropriate way to develop nationally consistent soil contaminant levels.

When asked about the content and function of a standard, most submitters suggested that it should at least contain a method for deriving soil contaminant values, and/or a tier-based assessment. Most of these submitters suggested a standard should contain both methods and numbers. There was also a strong level of consensus that if a standard contains numerical soil contaminant levels, they should be used as a “trigger level in a tiered risk-based assessment”. The use of soil contaminant levels as absolute thresholds was not favoured, and was advocated by only one submitter.

When asked if the guideline and standard criteria should include ecological as well as human health criteria, the majority wanted both criteria included. A smaller proportion advocated for a health-first or a health-only approach.

Other than a numerical or methodological standard, providing nationally consistent contaminated land rules was the most commonly suggested issue to which a standard could be applied.

Appropriateness

The majority of submitters (74%) responded to this discussion point. Figure 2 provides a breakdown of the responses.

Twenty-eight submitters agreed that a national guideline progressing to a standard is the most appropriate way to develop nationally consistent soil contaminant levels. Fourteen submitters (31%) conditionally or partially agreed with the discussion point and three (7%) disagreed.

Those submitters who agreed considered that a standard would:

• provide more certainty to the sector

• reduce variability in practice

• reduce confusion over the classification of contaminated land

• provide a clear benchmark for practice

• result in benefits far outweighing the costs.

Of those who conditionally agreed, conditions related to the quality of the guidance, the process for developing/deriving guidance, and the intended function of the soil contaminant values. Submitters who partially agreed were generally in favour of developing a national guideline, but were more reserved about the need for a standard, questioning its value over that of a national guideline.

The three respondents who disagreed were mostly concerned about inflexibility and the over-simplification of a standard approach. One also questioned the need for more contaminated land guidance, and felt that the existing guidance is sufficient.

Content and function

The majority (74%) of submitters responded to this discussion point. Figure 3 provides a breakdown of the responses.

The most common suggestion (46%) was that a standard should contain both methods and numbers. These submitters favoured a numerical trigger value supported by methods for derivation, methods for assessment, or both (see below).

Many (32%) felt the standard should contain methods only. It was argued that this would provide the greatest flexibility for site-specific assessment while providing a consistent derivation or assessment framework.

Of all the submitters who suggested a method:

• most wanted a method for deriving soil contaminant values (eg, setting tolerable daily intakes, mean daily intakes, acceptable level of risk, exposure parameters)

• others wanted a method for a tiered assessment of land (eg, how to derive site-specific values, such as assessing exposure pathways using site-specific information)

• others wanted methods to identify, record investigate, manage, remediate and report (eg, incorporating Contaminated Land Management Guidelines (CLMG) numbers 1–5).

Some submitters (12%) considered that using numbers only provided the greatest certainty, or more certainty than a method. One noted that the method for deriving the numbers needs to be transparent as to the degree of uncertainty in their calculation.

Four submitters wanted content other than methods and numbers in a standard (see section 4.5). Two cautioned against adopting over-protective numbers and recommended contaminant-specific cost-benefit analysis to guide setting numerical numbers. They highlighted cadmium from fertiliser inputs and polycyclic aromatic hydrocarbons.

Table 4: Suggestions for what the NES should contain, by submitter ID

Use of soil contaminant values

Thirty-one submitters (50%) responded to this discussion point. The responses were sorted into common themes, as outlined in Table 5.

Table 5: Submitter suggestions for the use of soil contaminant levels in a standard

Just under half (15) considered that if a standard contained soil contaminant levels, they should be used as a “trigger level” in a tier-based assessment. Exceeding the level would trigger further investigation. These investigation(s) would assess exposure pathways, considering site-specific factors to determine the sites’ contaminated status. Exceeding the trigger value would not automatically define the site as being contaminated. Some considered variations on this theme, including a tiered system with a mix of targets, regulatory and non-regulatory levels.

Four submitters wanted the level to be used to define contaminated land, which suggests a threshold approach. However, two of these submitters also suggested a trigger value type of response.

Four submitters suggested that levels should be used to define acceptable remediation or clean-up criteria. Three cautioned that standard soil levels should not be used as pollute-up-to levels. One argued for threshold values over risk-based guidelines. The argument was that threshold values are quantitative (with small grey areas), whereas risk-based values are difficult for the public to understand and subject to variables.

One submitter considered that levels should only be applied to residential land uses, because land-uses changes within the agricultural sector are adequately dealt with by New Zealand Food Safety Authority. In contrast, another submitter suggested that for widespread contamination (eg, agricultural, horticultural), levels should be used as thresholds associated with the protection of soil health and productivity that determine the ongoing and future management of the land.

Table 6: Suggestions for the use of contaminant values, by submitter ID

Human health and/or ecological criteria

Thirty-nine submitters (63%) responded to this discussion point. Figure 4 provides a breakdown of the responses.

Twenty-six submitters (66%) supported incorporating both ecological and human-health criteria. Twelve preferred health, with nine (23%) preferring health only and three (8%) favouring health first. One submitter stated to have no preference.

Submitters who wanted both human health and ecological criteria (26) considered that having both would significantly reduce the existing practitioner confusion and uncertainty over what criteria to apply when assessing land. Some, while supportive of developing both criteria, acknowledged the technical and policy difficulties of deriving and applying ecological criteria; ie, “what to protect” and “where to protect” (eg, commercial/industrial/residential).

Common threads in these responses included the following:

• ecological guidance is essential to help define contaminated land and help councils to address their statutory functions

• effects on ecology need to be seen to have an equal ranking with effects on human health.
  A focus on human-health criteria would result in the effects on ecological receptors being given lower priority, or even being ignored by practitioners

• any ecological criteria needed to include soil criteria protective of groundwater and surface water.

Submitters who favoured health only (9) were predominantly concerned about the complexity of ecological assessment relative to human health assessment and the wide variety of factors that need to be considered. One was concerned about the possibility of unnecessarily conservative outcomes as a result of deriving and implementing ecological criteria.

Three submitters, while cautioning against deriving ecological criteria in a standard, suggested that ecological assessment could be covered by broad guidance or long-term targets. Suggestions included:

• provide guidance on when ecological receptors are important and the methodology for how they should be considered

• provide guidance on establishing ecological parameters or trigger values via a risk-based assessment methodology

• adopt long-term targets for ecological criteria.

Submitters who responded with health first (3) supported eventually deriving ecological criteria, but considered that providing human health criteria was an immediate priority.

Table 7: Suggestions for human health and/or ecological criteria, by submitter ID

Other issues a standard could be applied to

Twenty-one (34%) submitters made suggestions about what other issues a standard could be applied to. The most common suggestion (6) for a standard was to address the inconsistency of contaminated land provisions in local government plans by applying a model plan rule. While model rules for both regional and district plans were suggested as candidates, district plans were most commonly suggested. Model rules were also a common suggestion as a guideline (see section 6.2).

Submitters explained that this type of standard would:

• ensure consistent and/or comprehensive planning (by overriding conflicting rules)

• improve clarity of roles and responsibilities between district and city councils and regional councils

• improve information on contaminated land and information for prospective landowners by triggering investigations for change in land use or subdivision of HAIL (Hazardous Activities and Industries) sites.

Three submitters wanted to see the roles and responsibilities of the relevant agencies detailed in a standard to clarify the existing uncertainty and confusion about agency roles. A range of additional suggestions were given, and these are summarised in Table 8.

Table 8: Suggestions for other issues a standard could be applied to, by submitter ID

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