Development of soil

contaminant limits:

approach and impact on beneficial use of

wastes

1. Welcome

2. Housekeeping

3. Purpose of workshop

4. Introductions

5. Overview – setting the scene

6. Presentation – Dr Jo Cavanagh

7. Discussion

8. Other

OUTLINE

• Inform industry on the methodology being used to

develop appropriate soil contaminant limits.

• Provide opportunity for industry feedback on

proposed approach and how this may impact on the

beneficial use of organic wastes /materials.

• Determine how Ecological Soil Guideline Values can

most effectively be used to enable beneficial use of

organic wastes /materials.

PURPOSE OF WORKSHOP:

INTRODUCTIONS

• NZ Biosolids Guidelines 2003

– Defined biosolids as any product that included WWTP sludge and met quality

standards

– Included soil replacement quality standards

– Did not consider non-biosolids quality to land

– Tighter default limits by 2013

– Expected to be reviewed within 5 years

• NZ Compost Standards 2005

– Contaminant limits link direct to NZ Biosolids Guidelines

• Other

– Waste Minimisation Act 2008

BACKGROUND – CONTAMINANT LIMITS

2013• Discussions between Water NZ, Centre for Biowaste Research,

WasteMINZ; joined by NZ Land Treatment Collective, Landcare Research and others

• Examination of issues – all organic wastes to land could have similar standards

• Why continue to deal with organic wastes independently?

BACKGROUND

GUIDELINES FOR ORGANIC WASTE TO

LAND

Product As Cd Cr Cu Ni Pb Zn

Greenwaste &

foodwaste

14 1.1 30 56 37 100 280

Chicken manure 26 0.06 23 43 6 6 295

Pig manure 1 0.06 2 49 2 2 580

Horse manure 3 0.02 6 13 3 8 87

Sheep pellets 3 0.10 9 22 4 17 140

Mushroom compost 36 0.08 8 94 6 10 270

Biosolids

Guidelines (max)

20 1.0 150 60 60 250 300

HEAVY METAL CONTENT OF SOME ORGANIC MATERIALS

SETTING APPROPRIATE CONTAMINANT LIMITS

Protection:

• People

• Animals

• Soil biota

• Plants

• Ground water

• Surface water

• Other

Benefits:

• Maximise benefits

from organic

materials applied

to land

• Water NZ,

• Centre for Biowaste Research,

• WasteMINZ,

• NZ Land Treatment Collective,

• Landcare Research,

• MFE, MOH, MPI, MBIE

• Other

NEW GUIDELINES: ORGANIC WASTE MATERIALS GUIDELINES

PROJECT

Developing ecological soil

guideline values (ECO-

SGV) for New Zealand

Jo Cavanagh

Why do we need Eco-SGVs for NZ?

Arsenic Copper Zinc DDT

CCME 17 (SQeAR),

26 (SQeCI)

[12 (SQG)]

63 (AR),

91 (CI)

200(AR),

360(CI)

0.7(AR),

12 (CI)

Dutch 85, [IV 76] 96, [IV 190] 720, [IV 720] 4, [IV 1.7]

Biosolids 20 100 300 0.5

UK/EU - 88 90 0.15

US 18 (P), -(I),

(43 B, M)

70 (P), 80(I),

29 (B), 49 (M)

160(P),

180(I),

-,-, 0.023(B),

0.091 (M)

AR- Agricultural, residential,

CI – Commercial, industrial

P – Plant; I – Invertebrate; B – Bird; M - Mammalian

Why are they different?

• Data used

– Data availability, screening criteria

• Derivation methodology

– Method

– Data (e.g. EC10/EC30)

– Level of protection

Need an agreed approach

• Envirolink Tools project

• Funded by MBIE

• 2 yr project commenced July 2014

• Advisory group:

– Regional council SIG (contaminated land,

land monitoring, land managers group), MfE,

MPI

• Two components

– Background soil concentration

– Eco-SGV

Project overview

Timeline

• By end Oct 2014

– Agreed scope

• Receptors

• Contaminants

Deriving values - what to protect?

Soil

Priority contaminants• As, Cd, Cr, Cu, F,

Pb, Zn• ∑DDTs,

BaP/PAH, TPH• Additional

contaminants if sufficient resources

Timeline

• By end Oct 2014

– Agreed scope

• By Sept 2015

– Background soil concentrations determined

– Agreed methodology

• Stakeholder workshops using Cu and Zn examples

• June 2016

• Eco-SGV for up to 10 contaminants

Objectives

• Develop nationally agreed methodologies

– for determining background soil

concentrations of naturally occurring elements

– ecological soil guideline values (Eco-SGVs)

• Use existing data to determine background

concentrations and Eco-SGVs for multiple

land-use scenarios

• Develop clear guidance for applying Eco-

SGVs for different purposes to ensure they

are applied correctly.

Related guidelines

• Organic waste

guideline

– WasteMinz,

NZWater, CIBR,

LTC

• Aim is to

complement, not

conflict with these

guidelines

Aims of workshop

• Raise awareness of process to develop Eco-

SGVs and enable stakeholder input

• Clarify application of Eco-SGVs in relation to

organic wastes

– Helps define appropriate levels of protection

Application of Eco-SGVs

Contaminated land

managementProtection of soil quality

“Discharge shall not create a contaminated site*”

Remedial activities

Preventing soil

contamination

Identifying level of effect

*wording from Regional Council Plans

Specific applications

• Application of wastes to land

– Cleanfill, managed fill

– Biosolids, food waste, manures

• Fertiliser application?

• Contaminated land management

– Identifying level of effect

– remediation

Aim: no

restriction on

land-use as a

result of

activity

Aim:

minimising

harm,

improving

environment

Background concentrations + waste applied

= new concentrations �beneficial or detrimental effect?

• Recommendation:

– Adaptation of

Australian

approach to

derive Eco-SGV

Developing NZ-specific SGVs

Special Series: Ecological Soil Clean-Up Values for Metals

Landuse as a means to determine

level of protection

Land-useStandard % protection

Biomagnificationprotectiona %

Urban residential* 80 85b

Public open space 80 85b

Commercial 60 65c

Industrial 60 65c

Agricultural 95d and 80e 98c,e and 85c,e

National Parks 99 99

*Should residential include urban and rural?

Proposed approach…

• Adaptation of Australian methodology

• “Added risk” approach i.e.

– Eco-SGV=background + added concentration

Concept is that background concentration

have a negligible contribution to toxicity,

thus it is only the amount “added” that is

of concern

Proposed approach…

• Adaptation of Australian methodology

• “Added risk” approach i.e.

– Eco-SGV=background + added concentration

• Ageing/leaching

Toxicity tests are often performed using

metal salts, which are much more

“available” to be taken up by plants,

invertebrates etc (bioavailability) than

contaminants that have been in the soil

for long periods of time

Proposed approach…

• Adaptation of Australian methodology

• “Added risk” approach i.e.

– Eco-SGV=background + added concentration

• Ageing

• Normalisation to a reference soil (accounting

for bioavailability)

– pH – 5.5, Clay – 23%, CEC 21 cmol/kg, Organic

carbon – 5.5%.

• Species-sensitivity distribution if sufficient

data (statistics)

General Process

• Data collation

Soil

• Microbial processes

– Respiration, nitrification

• Plants

– Yield, growth,

germination

• Invertebrates

– Reproduction, growth

General Process

• Selection and standardisation of toxicity data

– Added concentration

Endpoint Comment

EC10, EC20, NOEC Minimal/no effect

EC30, LOEC Low level of effect

EC50 50% effect

General Process

• Ageing/leaching

• Normalisation to standard reference soil• “Typical NZ soil”

• pH – 5.5, Clay – 23%, CEC 21 cmol/kg, Organic carbon – 5.5%

• Background concentration +ACL = Eco-SGV

Discussion points

• How can Eco-SGVs most effectively be used

to enable beneficial use of organic wastes?

• When should they apply - to the waste

material? to the soil after application?

• What are the range of organic wastes to be

considered?

Discussion points

• Is the land-use specific approach useful for

developing Eco-SGVs?

• What is the appropriate level of protection?

• How practical are the derived values i.e. what

actions can be undertaken to ensure

compliance? And what are the costs of those

actions?

• Are the proposed soil characteristics of the

New Zealand soil appropriately

representative?

Background concentrations

• Development of Eco-SGVs

– Added-risk approach

• National Environmental Standard for assessing

and managing contaminants in soil

– Soil contaminant standards – As, Cd

– Doesn’t apply if background is higher than SCS

• Tiered Fertiliser Management System - Cd

• Cleanfill guidelines

– Background or background + ½ Eco-SGV

What influences background?

• Geology, pedology ……

……but what are the key influences?

• Approach: use spatial databases……

• S-Map, Land Resource Information, Q-Map

• … and existing data to identify key influences

– Analysis at national scale, primarily regional

council data

– Focussed Southland/Otago (GNS Science)

• Evaluating

influence of

landuse

• Evaluating

influence of

selected

parameters

Further analyses

• Testing spatial autocorrelation

• Examine influence of soil texture

• Where landuse is a significant influencing

factor, reanalyse data subset

• Focussed Otago/Southland data

Developing SGVs for Cu and Zn

• Data collation

– Primarily data collated for Australian and EU

– Literature search for new studies

– (still some additional studies to include)

• Normalisation of toxicity data to NZ soil

– Normalisation relationships from a number of

recent studies specifically focussed on looking

at factors influencing technology

– CEC, pH primary factors influencing toxicity

Copper - SSD

Protection level

ACL (95%confidence limits) for different toxicological endpoints

EC10fresh EC10aged EC30fresh EC30aged EC50fresh EC50aged

99% 34

(26- 51)

60

(45-88)

70

(53-96)

127

(98-170)

110

(77- 162)

203

(152- 281)

95% 50

(39-71)

85

(66-119)

98

(79-131)

173

(141-221)

156

(120- 214)

277

(222-359)

90% 63

(49-88)

106

(84-143)

121

(100-155)

210

(174-259)

192

(150-255)

335

(277-424)

80% 85

(67-115)

142

(113-187)

161

(132-207)

272

(228- 340)

256

(204-340)

434

(364-543)

60% 139

(107-189)

226

(172-298)

251

(191-339)

409

(324-549)

404

(315-536)

653

(517-837)

Copper – added contaminant limit

Zinc-SSD

Zinc – added contaminant limit

Protection level

ACL (95%confidence limits) for different toxicological endpoints

EC10fresh EC10aged

EC30fresh EC30aged EC50fresh EC50aged

99% 29

(3.5-38)

84

(14-117)

44

(6-58)

127

(17-175)

84

(14-119)

255

(36-345)

95% 44

(21- 56)

131

(76-167)

66

(33-85)

197

(101-257)

131

(76-170)

393

(201-501)

90% 56

(43 74)

169

(134-219)

84

(65-115)

254

(194-344)

169

(133-229)

506

(391-672)

80% 78

(62 120)

237

(186-369)

117

(91-186)

355

(276-552)

237

(185-379)

709

(553 1124)

60% 130

(117-250)

397

(362-775)

196

(171-370)

593

(485-1128)

397

(363-775)

1185

(1025-2275)

Final Eco-SGVs

• Background concentration + added value

• What value of background

– Median

– 95th percentile

• Cu – 5-20 mg/kg (all landuses)

• Zn – 20-30 mg/kg (background,forestry)

The special case of Cu and Zn

Best remedial option is to actively manage soil to

encourage healthy soil community (provided off-site

risks managed)

High toxicity to ecological receptors

Ecological risk more likely to drive any remedial actions

Low toxicity to people

Essential elements – used by organisms to growBUT

Other contaminants

• Contaminants covered within Tools project

• As, Cd, Cr, Cu, F, Pb, Zn

• ∑DDTs, BaP/PAH, TPH

• Additional contaminants if sufficient resources

• Aim of project is to develop methodology

such that Eco-SGVs can be developed for

additional contaminants

• Emerging contaminants….

Emerging contaminants

• Typically organic compounds

– Wide range currently in use for different

purposes, pharmaceutical and personal care

products, plasticizers (e.g bisphenol A), anit-

microbial (e.g. triclosan), industrial

components

– Typically present in low concentrations, level

of effect often unknown

• Challenging to develop Eco-SGV due to

limited data

Discussion points

• How practical are the derived values i.e. what

actions can be undertaken to ensure

compliance? And what are the costs of those

actions?

• Is there room for consideration of different

values for the use of organic waste for the

improvement of degraded land?

• Priority contaminants for organic waste

Databases

• S-Map, Land Resource Information, Q-Map

• Pedological and geological information

• 1:50 000

• 30% coverage across NZ

LRIS

• Fundamental soils layer

• National pedological database

• 1:50 000 scale

• National Geological coverage

• 1:250 000

• Contains rock unit descriptions,

stratigraphic affiliations, and more…

Q-MAP

www.gns.cri.nz/qmap

http://data.gns.cri.nz/geology