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Measures as amended, taking into account amendments up to National Environment Protection (Assessment of Site Contamination) Amendment Measure 2013 (No. 1)
Administered by: Agriculture, Water and the Environment
Registered 03 Jun 2013
Start Date 16 May 2013

Commonwealth Coat of Arms

National Environment Protection (Assessment of Site Contamination) Measure 1999

as amended

made under section 14(1) of the

National Environment Protection Council Act 1994 (Cwlth), the National Environment Protection Council (New South Wales) Act 1995 (NSW), the National Environment Protection Council (Victoria) Act 1995 (Vic), the National Environment Protection Council (Queensland) Act 1994 (Qld), the National Environment Protection Council (Western Australia) Act 1996 (WA), the National Environment Protection Council (South Australia) Act 1995 (SA), the National Environment Protection Council (Tasmania) Act 1995 (Tas), the National Environment Protection Council Act 1994 (ACT) and the National Environment Protection Council (Northern Territory) Act 1994 (NT)

Compilation start date:                     16 May 2013

Includes amendments up to:            National Environment Protection (Assessment of Site Contamination) Amendment Measure 2013 (No. 1)

This compilation has been split into 22 volumes

Volume 1:       sections 1-6, Schedules A and B

Volume 2:       Schedule B1

Volume 3:       Schedule B2

Volume 4:       Schedule B3

Volume 5:       Schedule B4

Volume 6:       Schedule B5a

Volume 7:       Schedule B5b

Volume 8:       Schedule B5c

Volume 9:       Schedule B6

Volume 10:     Schedule B7 - Appendix 1

Volume 11:     Schedule B7 - Appendix 2

Volume 12:     Schedule B7 - Appendix 3

Volume 13:     Schedule B7 - Appendix 4

Volume 14:     Schedule B7 - Appendix 5

Volume 15:     Schedule B7 - Appendix 6

Volume 16:     Schedule B7 - Appendix B

Volume 17:     Schedule B7 - Appendix C

Volume 18:     Schedule B7 - Appendix D

Volume 19:     Schedule B7

Volume 20:     Schedule B8

Volume 21:     Schedule B9

Volume 22:     Endnotes

 

Each volume has its own contents

 

 

 

About this compilation

The compiled instrument

This is a compilation of the National Environment Protection (Assessment of Site Contamination) Measure 1999 as amended and in force on 16 May 2013. It includes any amendment affecting the compiled instrument to that date.

This compilation was prepared on 22 May 2013.

The notes at the end of this compilation (the endnotes) include information about amending Acts and instruments and the amendment history of each amended provision.

Uncommenced provisions and amendments

If a provision of the compiled instrument is affected by an uncommenced amendment, the text of the uncommenced amendment is set out in the endnotes.

Application, saving and transitional provisions for amendments

If the operation of an amendment is affected by an application, saving or transitional provision, the provision is identified in the endnotes.

Modifications

If a provision of the compiled instrument is affected by a textual modification that is in force, the text of the modifying provision is set out in the endnotes.

Provisions ceasing to have effect

If a provision of the compiled instrument has expired or otherwise ceased to have effect in accordance with a provision of the instrument, details of the provision are set out in the endnotes.

 

 

  

  

  


 

NatiNational Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of Site Contamination) Measure 1999 National Environment Protection (Assessment of

Schedule B5c

 

GUIDELINE ON

Ecological Investigation Levels for Arsenic, Chromium (III), Copper, DDT, Lead, Naphthalene, Nickel & Zinc

 

Explanatory note
The following guideline provides general guidance in relation to investigation levels for soil, soil vapour and groundwater in the assessment of site contamination.

This Schedule forms part of the National Environment Protection (Assessment of Site Contamination) Measure 1999 and should be read in conjunction with that document, which includes a policy framework and assessment of site contamination flowchart.

The original Schedule B5 to the National Environment Protection (Assessment of Site Contamination) Measure 1999 has been repealed and replaced by this document, together with Schedule B5a and Schedule B5b.

The National Environment Protection Council (NEPC) acknowledges the contribution of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the NSW Environment Protection Authority and the NSW Environmental Trust to the development of this Measure.

 

 

 

 

 


Contents
Guideline on ecological investigation levels

                                                                                                                    Page

1                             Introduction                                                               1

1.1             Objectives                                                                                                  1

1.2             Terminology                                                                                              1

2                             Overview of the method for deriving soil quality
 guidelines                                                                  
2

2.1             Precision of estimates and rounding of added contaminant limits       4

3                             Zinc                                                                             7

3.1             Zinc compounds considered                                                                    7

3.2             Exposure pathway assessment                                                                7

3.3             Toxicity data                                                                                             7

3.4             Normalisation relationships                                                                     9

3.5             Sensitivity of organisms to zinc                                                              10

3.6             Calculation of soil quality guidelines for fresh zinc contamination    11

3.6.1                Calculation of soil quality guidelines for fresh zinc
contamination based on no observed effect concentration
and 10% effect concentration toxicity data                               
11

3.6.1.1                 Calculation of soil-specific added contaminant limits                        11

3.6.1.2                 Calculation of ambient background concentration values                14

3.6.1.3                 Examples of soil quality guidelines for fresh zinc
contamination based on no observed effect concentration
and 10% effect concentration data                                                         
15

3.6.2                Calculation of soil quality guidelines based on protecting
aquatic ecosystems from leaching of fresh zinc contamination 
15

3.6.3                Calculation of soil quality guidelines for fresh zinc
contamination based on lowest observed effect
concentration and 30% effect concentration toxicity data,
and based on 50% effect concentration toxicity data                
17

3.6.3.1                 Calculation of soil-specific added contaminant limits                        17

3.6.3.2                 Calculation of ambient background concentration values                20

3.6.3.3                 Examples of soil quality guidelines for fresh zinc contamination
based on lowest observed effect concentration and 30% effect concentration data, and based on 50% effect data                                                                                                      
20

3.7             Calculation of soil quality guidelines for aged zinc contamination    21

3.7.1                Calculation of an ageing and leaching factor for zinc                21

3.7.2                Calculation of soil quality guidelines for aged zinc
contamination based on no observed effect concentration
and 10% effect concentration toxicity data                               
21

3.7.2.1                 Calculation of added contaminant limits for aged zinc
 contamination based on no observed effect concentration
and 10% effect concentration toxicity data                                          
21

3.7.2.2                 Calculation of ambient background concentration values                24

3.7.2.3                 Examples of soil quality guidelines for Australian soils with
aged zinc contamination based on no observed effect
concentration and 10% effect concentration data                              
24

3.7.3                Calculation of soil quality guidelines for aged zinc
contamination based on lowest observed effect concentration
and 30% effect concentration toxicity data and based on
50% effect concentration toxicity data                                      
25

3.7.3.1                 Calculation of added contaminant limits for aged zinc
contamination based on lowest observed effect concentration
and 30% effect concentration and based on 50% effect
concentration toxicity data                                                                       
25

3.7.3.2                 Calculation of ambient background concentrations                           28

3.7.3.3                 Examples of soil quality guidelines for Australian soils with
aged zinc contamination based on lowest observed effect
concentration and 30% effect concentration data, and based
on 50% effect concentration toxicity data                                            
28

3.8             Reliability of the zinc soil quality guidelines                                         29

3.9             Comparison with other guidelines                                                        29

4                             Arsenic                                                                      31

4.1             Arsenic compounds considered                                                             31

4.2             Exposure pathway assessment                                                              31

4.3             Toxicity data                                                                                           31

4.4             Normalisation relationships                                                                   32

4.5             Sensitivity of organisms to arsenic                                                        33

4.6             Calculation of soil quality guidelines for fresh arsenic
contamination                                                                                        
33

4.6.1                Calculation of soil quality guidelines for fresh arsenic
contamination based on no observed effect concentration and
10% effect concentration toxicity data                                      
34

4.6.1.1                 Calculation of ambient background concentration values                34

4.6.2                Calculation of soil quality guidelines for fresh arsenic
contamination based on protecting aquatic ecosystems from
leaching                                                                                       
35

4.6.3                Calculation of soil quality guidelines for fresh arsenic
contamination based on lowest observed effect concentration
and 30% effect concentration toxicity data, and based on
50% effect concentration toxicity data                                      
35

4.7             Calculation of soil quality guidelines for aged arsenic
contamination                                                                                        
36

4.7.1                Calculation of an ageing and leaching factor for arsenic           36

4.7.2                Calculation of soil quality guidelines for aged arsenic
contamination                                                                             
36

4.7.3                Calculation of ambient background concentration values         36

4.8             Reliability of the soil quality guidelines                                                 37

4.9             Comparison with other guidelines                                                        37

5                             Naphthalene                                                             38

5.1             Compounds considered                                                                          38

5.2             Exposure pathway assessment                                                              38

5.3             Toxicity data                                                                                           38

5.4             Normalisation relationships                                                                   39

5.5             Sensitivity of organisms to naphthalene                                               39

5.6             Calculation of soil quality guidelines for fresh naphthalene
contamination                                                                                        
40

5.6.1                Calculation of soil quality guidelines for fresh naphthalene contamination based on no observed effect concentration and
10% effect concentration toxicity data                                      
40

5.6.1.1                 Calculation of ambient background concentration values                41

5.6.2                Calculation of soil quality guidelines for fresh naphthalene contamination based on lowest observed effect concentration
and 30% effect concentration data, and based on 50% effect concentration toxicity data                                                                                                     
41

5.7             Calculation of soil quality guidelines for aged naphthalene
contamination                                                                                        
41

5.8             Metabolites of naphthalene                                                                    41

5.9             Reliability of the soil quality guidelines                                                 42

5.10          Comparison with other guidelines                                                        42

6                             DDT                                                                          43

6.1             Compounds considered                                                                          43

6.2             Pathway risk assessment                                                                        43

6.3             Toxicity data                                                                                           43

6.4             Normalisation relationships                                                                   43

6.5             Sensitivity of organisms to DDT                                                            43

6.6             Calculation of soil quality guidelines for fresh DDT
contamination                                                                                        
45

6.6.1                Calculation of generic soil quality guidelines for fresh DDT contamination based on no observed effect concentration and
10% effect concentration toxicity data                                      
45

6.6.2                Calculation of soil quality guidelines for fresh DDT
contamination based on lowest observed effect concentration
data and 30% effect concentration data, and based on 50%
effect concentration toxicity data                                               
46

6.7             Calculation of soil quality guidelines for aged contamination            47

6.8             Reliability of soil quality guidelines                                                       47

6.9             Important metabolites of DDT                                                              47

6.10          Comparison with other guidelines                                                        47

7                             Copper                                                                      49

7.1             Copper compounds considered                                                             49

7.2             Exposure pathway assessment                                                              49

7.3             Toxicity data                                                                                           49

7.4             Normalisation relationships                                                                   51

7.5             Sensitivity of organisms to copper                                                         54

7.6             Calculation of soil quality guidelines for fresh copper
contamination                                                                                        
55

7.6.1                Calculation of soil quality guidelines for fresh copper
contamination based on no observed effect concentration and
10% effect concentration toxicity data                                      
55

7.6.1.1                 Calculation of soil-specific added contaminant limits                        55

7.6.1.2                 Calculation of ambient background concentration values                57

7.6.1.3                 Examples of soil quality guidelines for fresh copper
contamination based on no observed effect concentration
and 10% effect concentration data                                                         
58

7.6.2                Calculation of soil quality guidelines for fresh copper
contamination based on lowest observed effect concentration
and 30% effect concentration toxicity data, and on 50% effect concentration data       
58

7.6.2.1                 Calculation of soil-specific added contaminant limits                        58

7.6.2.2                 Calculation of ambient background concentration values                60

7.6.2.3                 Examples of soil quality guidelines for fresh copper
contamination in Australian soils based on lowest observed
effect concentration and 30% effect concentration toxicity
data, and on 50% effect concentration data.                                        
60

7.7             Calculation of soil quality guidelines for aged copper
contamination                                                                                        
62

7.7.1                Calculation of an ageing and leaching factor for copper           62

7.7.2                Calculation of soil quality guidelines for aged copper
contamination based on no observed effect concentration
and 10% effect concentration toxicity data                               
62

7.7.2.1                 Calculation of soil-specific added contaminant limits                        62

7.7.2.2                 Calculation of ambient background concentration values                63

7.7.2.3                 Examples of soil quality guidelines for aged copper
contamination in Australian soils based on no observed effect concentration and 10% effect concentration data.                                                                                      
63

7.7.3                Calculation of soil quality guidelines for aged copper
contamination based on LOEC and 30% effect concentration
toxicity data, and on 50% effect concentration data.                
64

7.7.3.1                 Calculation of soil-specific added contaminant limits                        64

7.7.3.2                 Calculation of ambient background concentration values                65

7.7.3.3                 Examples of soil quality guidelines for aged copper
contamination in Australian soils based on lowest observed
effect concentration and 30% effect concentration data                  
66

7.8             Reliability of the soil quality guidelines                                                 67

7.9             Comparison with other guidelines                                                        67

8                             Lead                                                                          69

8.1             Lead compounds considered                                                                 69

8.2             Exposure pathway assessment                                                              69

8.3             Toxicity data                                                                                           70

8.4             Normalisation relationships                                                                   71

8.5             Sensitivity of organisms to lead                                                             71

8.6             Calculation of soil quality guidelines for fresh lead
contamination                                                                                        
72

8.6.1                Calculation of soil quality guidelines for fresh lead
contamination based on NOEC and 10% effect concentration
toxicity data                                                                                
72

8.6.1.1                 Calculation of soil-specific added contaminant limits                        72

8.6.1.2                 Calculation of ambient background concentration values                73

8.6.1.3                 Examples of soil quality guidelines for fresh lead contamination
in Australian soils based on no observed effect concentration
 and 10% effect concentration data                                                        
73

8.6.2                Calculation of soil quality guidelines for fresh lead
contamination based on LOEC and 30% effect concentration
toxicity data and on 50% effect concentration data                  
74

8.6.2.1                 Calculation of soil-specific added contaminant limits                        74

8.6.2.2                 Calculation of ambient background concentration values                74

8.6.2.3                 Examples of soil quality guidelines for fresh lead contamination
in Australian soils based on lowest observed effect concentration
and 30% effect concentration data and on 50% effect
concentration data                                                                                       
74

8.7             Calculation of soil quality guidelines for aged lead contamination    75

8.7.1                Calculation of an ageing and leaching factor                             75

8.7.2                Calculation of soil quality guidelines for aged lead contamination
based on NOEC and 10% effect concentration toxicity data    
76

8.7.2.1                 Calculation of soil-specific added contaminant limits                        76

8.7.2.2                 Calculation of ambient background concentration values                76

8.7.2.3                 Examples of soil quality guidelines for aged lead contamination
in Australian soils based on no observed effect concentration
and 10% effect concentration data.                                                        
76

8.7.3                Calculation of soil quality guidelines for aged lead
contamination based on LOEC and 30% effect concentration
toxicity data and on 50% effect concentration data                  
77

8.7.3.1                 Calculation of added contaminant limits                                               77

8.7.3.2                 Calculation of ambient background concentration values                77

8.7.3.3                 Examples of soil quality guidelines for aged lead contamination
in Australian soils based on lowest observed effect concentration
and 10% effect concentration data and on 50% effect
concentration data.                                                                                      
77

8.8             Reliability of the soil quality guidelines                                                 79

8.9             Comparison with other guidelines                                                        79

9                             Nickel                                                                        80

9.1             Nickel compounds considered                                                               80

9.2             Exposure pathway assessment                                                              80

9.3             Toxicity data                                                                                           80

9.4             Normalisation relationships                                                                   82

9.5             Sensitivity of organisms to nickel                                                          83

9.6             Calculation of soil quality guidelines for fresh nickel
contamination                                                                                        
84

9.6.1                Calculation of soil quality guidelines for fresh nickel
contamination based on no observed effect concentration
and 10% effect concentration toxicity data                               
84

9.6.1.1                 Calculation of soil-specific added contaminant limits                        84

9.6.1.2                 Calculation of ambient background concentration values                85

9.6.1.3                 Examples of soil quality guidelines for fresh nickel
contamination in Australian soils based on no observed
effect concentration and 10% effect concentration data                  
86

9.6.2                Calculation of soil quality guidelines for fresh nickel
contamination based on LOEC and 30% effect concentration
toxicity data, and on 50% effect concentration data                 
87

9.6.2.1                 Calculation of soil-specific added contaminant limits                        87

9.6.2.2                 Calculation of ambient background concentration values                87

9.6.2.3                 Examples of soil quality guidelines for fresh nickel
contamination in Australian soils based on lowest observed
effect concentration and 30% effect concentration data,
and based on 50% data                                                                              
87

9.7             Calculation of soil quality guidelines for aged nickel
contamination                                                                                        
89

9.7.1                Calculation of ageing and leaching factors for nickel                89

9.7.2                Use of ageing and leaching factors in the methodology              89

9.7.3                Calculation of soil quality guidelines for aged nickel
contamination based NOEC and 10% effect concentration
toxicity data                                                                                
90

9.7.3.1                 Calculation of soil-specific added contaminant limits                        90

9.7.3.2                 Calculation of ambient background concentration values                90

9.7.3.3                 Examples of soil quality guidelines for aged nickel
contamination in Australian soils based on no observed
effect concentration and 10% effect concentration data                  
90

9.7.4                Calculation of soil quality guidelines for aged nickel
contamination based on LOEC and 30% effect concentration
toxicity data, and on 50% effect concentration data                 
91

9.7.4.1                 Calculation of soil-specific added contaminant limits                        91

9.7.4.2                 Calculation of ambient background concentration values                92

9.7.4.3                 Examples of soil quality guidelines for fresh nickel
contamination in Australian soils based on lowest observed
effect concentration and 30% effect concentration data,
and based on 50% effect concentration data                                        
92

9.8             Reliability of the soil quality guidelines                                                 93

9.9             Comparison with other guidelines                                                        93

10                          Trivalent chromium                                                 95

10.1          Chromium (III) compounds considered                                               95

10.2          Exposure pathway assessment                                                              95

10.3          Toxicity data                                                                                           95

10.4          Normalisation relationships                                                                   96

10.5          Sensitivity of organisms to trivalent chromium                                    97

10.6          Calculation of soil quality guidelines for fresh trivalent
chromium contamination                                                                      
98

10.6.1             Calculation of added contaminant limits for fresh trivalent
chromium contamination                                                            
98

10.6.2             Calculation of ambient background concentration values for
fresh trivalent chromium contamination                                    
98

10.6.3             Examples of soil quality guidelines for fresh trivalent
chromium contamination in Australian soils                              
99

10.7          Calculation of soil quality guidelines for aged trivalent
chromium contamination                                                                    
100

10.7.1             Calculation of an ageing and leaching factor for trivalent
chromium                                                                                  
100

10.7.2             Calculation of added contaminant limits for aged trivalent
chromium contamination                                                          
101

10.7.3             Calculation of ambient background concentration values       101

10.7.4             Examples of soil quality guidelines for aged trivalent
chromium contamination in Australian soils                            
102

10.8          Reliability of the soil quality guidelines                                               103

10.9          Comparison with other guidelines                                                      103

11                          Summary                                                                105

12                          Bibliography                                                          109

13                          Appendices                                                             126

13.1          Appendix A: Raw toxicity data for zinc                                             126

13.2          Appendix B. Raw toxicity data for arsenic                                        135

13.3          Appendix C: Raw toxicity data for naphthalene                               139

13.4          Appendix D: Raw toxicity data for DDT                                           141

13.5          Appendix E: Raw toxicity data for copper                                        143

13.6          Appendix F: Explanation of the selection of the soil properties
that control the added contaminant limits for copper                      
158

13.7          Appendix G. Raw toxicity data for lead                                             159

13.8          Appendix H: Raw toxicity data for nickel                                          162

13.9          Appendix I: Raw toxicity data for trivalent chromium                    171

14                          Glossary                                                                  175

15                          Shortened forms                                                      178

 

 


1                  Introduction

1.1              Objectives

The objective of this guideline is to derive EILs for arsenic (As), copper (Cu), chromium III (Cr (III)), dichlorodiphenyltrichloroethane (DDT), naphthalene, nickel (Ni), lead (Pb) and zinc (Zn) using the methodology detailed in Schedule B5b to:

·         illustrate the flexibility of the methodology—being able to derive soil contaminant limits that provide different levels of protection, and use different toxicity data

·         illustrate the magnitude and appropriateness of the  soil contaminant limits

·         compare the EILs with those of overseas jurisdictions.

1.2              Terminology

The term ‘soil quality guideline’ (SQG) is used in this guideline to describe any concentration-based limit for contaminants in soils.

 

A combination of lowest observed effect concentration (LOEC) and 30% effect concentration data (EC30) has been adopted in the NEPM for the derivation of EILs. Equivalent data for EC10 and EC50 is included for information purposes only.

2                  Overview of the method for deriving soil quality guidelines

Soil quality guidelines can have various purposes. The National Environment Protection (Assessment of Site Contamination) Measure (NEPM) contains a specific type of SQG, the ecological investigation level (EIL), to guide the assessment of contaminated sites in Australia. The EILs were derived in such a manner that when they are exceeded it indicates that terrestrial ecosystems may experience harmful effects due to the presence of contaminants. The EILs are thus used to indicate when further investigation is necessary.

 

However, SQGs with other purposes can and have been developed. For example, the Dutch have three sets of SQGs, each with a different purpose. These are target levels (their purpose is to indicate the long-term goals for the concentration of contaminants), maximum permissible levels (their purpose is to define the maximum level of contamination that is considered acceptable), and intervention levels (their purpose is to define the maximum permitted concentration before some immediate action is required).

 

As a result of consultation conducted in developing the Australian methodology in November 2008, three different sets of ecotoxicity data were used to derive SQGs. The three sets of SQGs are termed SQG(NOEC & EC10), SQG(LOEC & EC30) and SQG(EC50) reflecting the type of ecotoxicity data that was used in their generation. A summary of the three types of SQGs, the data used and likely ecotoxicological effects that would be expected to occur if these are met is presented in Table 1. A combination of lowest observed effect concentration (LOEC) and 30% effect concentration data (EC30) has been adopted in the NEPM for the derivation of EILs.

Table 1. The relationship between the three types of soil quality guidelines (SQGs), the data that is used to derive the SQGs and the type of toxic effects that would be experienced if the SQGs are met.

Type of SQG

Toxicity data used to calculate the SQGs

Expected toxic effects if the SQG is not exceeded

SQG(NOEC & EC10)

NOEC and EC10

slight toxic effects

SQG(LOEC & EC30)

LOEC and EC30

moderate toxic effects

SQG(EC50)

EC50

significant toxic effects

 

An overview of the SQG derivation methodology (detailed in Schedule B5b) is presented in Figure 1. One of the key aims in developing the methodology was to account for the availability and toxicity of the contaminant in the soil being studied. To do this, key soil and site-specific factors that are known to modify the toxicity of contaminants had to be accounted for. One factor that was incorporated into the methodology was the background concentration. In order to do this, the data used to derive the SQGs was expressed in terms of the amount of contaminant that had to be added to the soil to cause toxicity. When this toxicity data was used in accordance with the methodology, the resulting value was termed the added contaminant level (ACL). An ambient background concentration (ABC) specific to the soil being investigated was then added to the ACL to calculate the SQG.

 

ACL values are generated as part of the methodology of deriving SQGs. Thus, it is necessary to differentiate the ACLs generated in deriving SQG(NOEC & EC10) from those generated in deriving SQG(LOEC & EC30) and SQG (EC50) values. The ACL generated in deriving an SQG(NOEC & EC10) is termed the NOEC and EC10-based ACL (ACL(NOEC & EC10)). Similarly, ACLs generated in deriving SQG(LOEC & EC30) and SQG (EC50) values are referred to as the LOEC and EC30-based ACL (ACL(LOEC & EC30)) and the EC50-based ACL (ACL(EC50)).

 

 

Figure 1. Overview of the  methodology for deriving soil quality guidelines based on NOEC and EC10 data (SQG(NOEC & EC10)) indicated by the green (far left) arrows, based on LOEC and EC30 data (SQG(LOEC & EC30)) indicated by the orange (middle) arrows and based on EC50 data (SQG(EC50)) indicated by the red (far right) arrows. As part of this process, ACLs and ABCs are calculated. The differences between the three SQGs are presented in Table 1.

The key steps in the methodology are:

1.        determining the purpose of the SQG and the appropriate level of protection

2.        determining the most important exposure pathways

3.        collating and screening the toxicity data

4.        determining whether the contamination is fresh or aged and whether there are ageing/leaching factors available to account for this

5.        normalising the toxicity data

6.        calculating the ACL

7.        accounting for biomagnification

8.        measuring or calculating the ABC

9.        calculating SQG(NOEC & EC10),  SQG(LOEC & EC30) and SQG(EC50) values for fresh contamination in soils with different land uses

10.     calculating SQG(NOEC & EC10),  SQG(LOEC & EC30) and SQG(EC50) values for aged contamination in soils with different land uses.

These key steps and the decision pathway involved in deriving ACL(NOEC & EC10) and SQG(NOEC & EC10) values are provided in Figure 2 below. Exactly the same procedure would be used to derive SQG(LOEC & EC30) and SQG(EC50) values, except that different toxicity data would be used (Table 1). Details of the methodology for calculating SQGs are provided in Schedule B5b.

 

Land has a variety of potential uses, and the level of protection that is appropriate for each land use varies. For example, it is appropriate for a higher level of protection to be applied to areas of ecological significance compared to industrial land. The recommended levels of protection for various land uses are provided in Schedule B5b and are used in this guideline.  For contaminants that do not biomagnify, the recommended level of protection of species for areas of ecological significance, urban residential/public open space and commercial/industrial land are 99%, 80% and 60% respectively. For contaminants that biomagnify, the recommended levels of protection of species for areas of ecological significance, urban residential/public open space and commercial/industrial land are 99%, 85% and 65% respectively. SQGs were generated for areas of ecological significance, urban residential land/public open space, and commercial/industrial land uses.

 

The contamination at many contaminated sites is not fresh, rather it has been there for some years. The biological availability (bioavailability) and toxicity of many contaminants decreases over time (that is, it ages) due to binding to soil particles, chemical and biological degradation and a range of other processes. Furthermore, in many laboratory-based ecotoxicity experiments that spike soils with soluble metal salts, ecotoxicity is overestimated due to a lack of leaching of soluble salts which affect metal sorption. These factors have been addressed in recent risk assessments for metals in soils using ’ageing/leaching‘ factors, and can be accounted for by multiplying the toxicity data by an ageing/leaching factor and thus deriving SQGs for aged contamination. Site-specific assessments of a contaminant’s bioavailability can also be made, but these are usually conducted as part of a more detailed site-specific (Tier 2) ecological risk assessment. When ageing/leaching factors were available for the test chemicals examined in this study, SQGs were derived for aged contamination.

 

When contaminants are introduced to soil, some will bind strongly to the soil while others are mobile and will move off-site. Leaching to groundwater is a key off-site migration pathway and can result in aquatic ecosystems being exposed to contaminants. Therefore, the potential of contaminants to leach is an important characteristic that affects the environmental fate and effect they cause. The leaching potential is not controlled solely by the physicochemical properties of contaminants, but also by the properties of the soil containing the contaminant and climatic conditions. It is not possible or appropriate to account for the potential to leach in deriving practical SQGs at a generic level, rather this should be done as part of a more detailed site-specific ecological risk assessment.

 

Given the available data, the most complete set of SQGs was derived for each of the eight contaminants. A summary of what SQGs could be derived is presented below.

·         For chromium (III), copper, nickel and zinc, it was possible to derive a set of soil-specific SQGs using each of the three types of toxicity data for each of the three land uses for both fresh and aged contamination.

·         For arsenic and lead, it was possible to derive generic (not soil-specific) SQGs using each of the three types of toxicity data for each of the three land uses and for both fresh and aged contamination.

·         For DDT and naphthalene, it was possible to derive generic (not soil-specific) SQGs using each of the three types of toxicity data for each of the three land uses but only for fresh contamination.

 

In addition, SQGs that account for the potential of contaminants to leach (and therefore should protect aquatic ecosystems) were derived for arsenic and zinc. This was only done for these contaminants to illustrate how this is done and what effect it has on the resulting SQGs compared to the SQGs that do not account for leaching.

2.1              Precision of estimates and rounding of added contaminant limits

In order to increase the readability and ease of use of this report the ACL, ABC and SQG values presented in the various tables have all been rounded off using the following scheme:

·         all values <1 were rounded off to the nearest 0.1

·         all values between 1 and 10 were rounded off to the nearest whole number

·         all values between 10 and 100 were rounded off to the nearest multiple of 5

·         all values between 100 and 1000 were rounded off to the nearest multiple of 10

·         all values greater than 1000 were rounded off to the nearest 100 units.

Figure 2. Schematic of the methodology for deriving soil quality guidelines (SQGs) (modified from Heemsbergen et al. 2008). Green arrows show the path when the preceding question was answered with a ‘yes’ while the red arrows indicate the path when the answer was ‘no’. Blue arrows indicate the path when there is no choice.

3                  Zinc

3.1              Zinc compounds considered

The SQGs for Zn were derived using data for the following:

·         zinc metal (CAS No. 7440-66-6)

·         zinc oxide (CAS No. 1314-13-2)

·         zinc distearate (CAS Nos 557-05-1/91051-01-3)

·         zinc chloride (CAS No. 7646-85-7)

·         zinc sulphate (CAS No. 7733-02-0).

3.2              Exposure pathway assessment

The two key considerations in determining the most important exposure pathways for inorganic contaminants are whether they biomagnify (see Glossary) and whether they have the potential to leach to groundwater.

 

A surrogate measure of the potential for a contaminant to leach is its water-soil partition coefficient (Kd). If the logarithm of the Kd (log Kd) of an inorganic contaminant is less than 3 then it is considered to have the potential to leach to groundwater (Schedule B5b). The Australian National Biosolids Research Program (NBRP) measured the log Kd of Zn in 17 agricultural soils throughout Australia. These measurements showed that in most soils the log Kd of Zn was below 3 L/kg (unpublished data). The log Kd value for Zn reported by Crommentuijn et al. (2000) was 2.2 L/kg. Therefore, there is the potential for Zn in some soils to leach to groundwater and affect aquatic ecosystems. However, the methodology for EIL derivation (Schedule B5b) does not advocate the routine derivation of EILs that account for leaching potential. Rather, it advocates that this is done on a site-specific basis as appropriate. However, the calculations of Zn SQGs that account for leaching have been included here as an illustration of the process and the effect that this has on the resulting soil quality guidelines.

 

Zinc is an essential element and, as such, concentrations of Zn in tissue are highly regulated and it does not biomagnify (Louma & Rainbow 2008; Schedule B5b). Therefore, the biomagnification route of exposure does not need to be considered for Zn and the SQGs will only account for direct toxicity.

3.3              Toxicity data

Zinc is a well-studied inorganic contaminant and therefore a large dataset of toxicity values was available. Most studies presented their toxicity data in terms of added concentration (that is, the concentration of the contaminant added to the soil that causes a specified toxic effect) and so could be used without further modification. Some toxicity data was expressed in terms of total contaminant concentration but the background concentrations were reported. In such cases, the toxicity data was converted to an added concentration basis by subtracting the background from the total concentration. If toxicity data was expressed in terms of total contaminant concentration but the background concentration was not reported then the Dutch background correction equation (Lexmond et al. 1986) was used to estimate the background concentration.

 

background Zn = 1.5 * [2 * organic matter (%) + clay content (%)]                (equation 1)

 

The background concentration was then subtracted from the total concentration data to derive the added concentration toxicity value.

 

The toxicity database used to calculate the SQG(NOEC & EC10) values for Zn included EC10 and NOEC toxicity data for nine soil processes (Table 2), 14 invertebrate species and 1 invertebrate community measurement (Table 3) and 22 plant species (Table 4). The raw data used to generate Tables 2–4 is provided in Appendix A. There was sufficient data (that is, toxicity data) for at least five species or soil processes that belong to at least three taxonomic or nutrient groups (Schedule B5b) available to derive SQG(NOEC & EC10) values using a species sensitivity distribution (SSD) methodology. Given that Zn does not biomagnify, the level of protection recommended for non-biomagnifying contaminants was used to generate the SQG for each land use.

 

Table 2. The geometric mean values of the zinc toxicity data (expressed in terms of added Zn) for individual soil processes.

Soil process

Geometric means (mg/kg added Zn)

 

EC10 or NOEC

EC30 or LOEC

EC50

Acetate decomposition

187

280

560

Amidase

121

182

364

Ammonification

98

148

295

Arylsulphatase

289

434

868

Glucose decomposition

274

1169

2904

Nitrate reductase

56

84

168

Nitrification

455

706

930

Phosphatase

674

1011

2022

Respiration

104

157

313

Table 3. The geometric mean values of zinc (Zn) toxicity data (as added Zn) for soil invertebrate species and an invertebrate community.

Species/endpoint

Geometric means (mg/kg added Zn)

Common name

Scientific name

EC10 or NOEC

EC30 or LOEC

EC50

Earthworm

Aporrectodea caliginosa

223

274

391

Earthworm

Aporrectodea rosea

390

407

436

Earthworm

Eisenia fetida

201

296

575

Earthworm

Lumbriculus rubellus

220

285

443

Earthworm

Lumbriculus terrestris

1062

1257

1675

Nematode

Acrobeloides sp.

221

332

663

Nematode

Caenorhabditis elegans

122

183

366

Nematode

C. elegans (dauer larvae)

689

1034

2068

Nematode

Community nematodes

306

459

919

Nematode

Eucephalobus sp.

135

202

403

Nematode

Plectus sp.

23

35

70

Nematode

Rhabditidae sp.

199

299

597

Potworm

Enchytraeus albidus

121

181

363

Potworm

Enchytraeus crypticus

276

414

828

Springtail

Folsomia candida

188

283

565

 

Table 4. The geometric mean values of the zinc (Zn) toxicity data (expressed in terms of added Zn) for individual plant species.

Plant species

Geometric means (mg/kg added Zn)

Common name

Scientific name

EC10 or NOEC

EC30 or LOEC

EC50

Alfalfa

Medicago sativa

198

297

595

Barley

Hordeum vulgare

83

233

495

Beet

Beta vulgaris

198

297

595

Black or white lentil

Vigna mungo

95

142

284

Canola

Brassica napus

230

328

409

Common vetch

Vicia sativa

42

63

127

Cotton

Gossypium sp.

272

288

293

Fenugreek

Trigonella foenum graecum

106

159

318

Lettuce

Latuca sativa

264

396

793

Maize

Zea mays

202

304

581

Millet

Panicum milaceum

540

1580

2026

Oats

Avena sativa

222

333

667

Onion

Allium cepa

66

99

198

Pea

Pisum sativum

264

396

793

Peanuts

Arachis hypogaea

140

224

280

Red clover

Trifolium pratense

39

59

117

Sorghum

Sorghum sp.

123

254

444

Spinach

Spinacia oleracea

132

198

396

Sugar cane

Sacharum

3220

4830

9661

Tomato

Lycopersicon esculentum

264

396

793

Triticale

Tritosecale sp.

998

1364

1658

Wheat

Triticum aestivum

640

928

1172

 

3.4              Normalisation relationships

A normalisation relationship is an empirical model that predicts the toxicity of a single contaminant to a single species using soil physicochemical properties (for example, soil pH and organic carbon content). Seven normalisation relationships were reported in the literature for Zn toxicity (Table 5). Three were developed for Australian soils (Broos et al. 2007; Warne et al. 2008a; Warne et al. 2008b) and four have been derived for European soils (Lock & Janssen 2001; Smolders et al. 2003). Three of the relationships were for plants, two for microbial functions and two for soil invertebrates. Of these, relationships 1-4, 6 and  7 were used to derive Zn SQGs. Relationship number 5 for wheat was not used, as an equivalent field-based relationship for Australian soils was available and field-based normalisation relationships provide better estimates of toxicity in the field (Warne et al. 2008a) and thus are preferred to laboratory-based relationships (Schedule B5b).

 

Normalisation relationships are used to account for the effect of soil characteristics on toxicity data, so the resulting toxicity data more closely reflect the inherent sensitivity of the test species. All the Zn toxicity data in Tables 2–4 was normalised to their equivalent toxicity in the recommended Australian reference soil (Schedule B5b) (Table 6). Depending on the conditions under which the toxicity tests were conducted, the normalised toxicity data could be higher or lower in the reference soil compared to the original toxicity data in the test soil.

 

Table 5. Normalisation relationships for the toxicity of zinc to soil invertebrates, soil processes and plants.

Eqn no.

Species/soil process

Y parameter

X parameter(s)

Reference

1

E. fetida

(earthworm)

log EC50

 

0.79 * log CEC

Lock and Janssen 2001

2

F. candida

(collembola)

log EC50

 

1.14 * log CEC

Lock and Janssen 2001

3

PNR

log EC50

0.15 * pH

Smolders et al. 2003

4

SIN

log EC50

0.34 * pH + 0.93

Broos et al. 2007

5

T. aestivum

(wheat)

log EC10

0.14 * pH + 0.89 * log OC + 1.67

Warne et al. 2008a

6

log EC10

0.271 * pH +0.702 * CEC + 0.477

Warne et al. 2008b

7

log EC50

0.12 * pH +0.89 * log CEC + 1.1

Smolders et al. 2003

CEC = cation exchange capacity (cmolc/kg); OC = organic carbon content (%); PNR = potential nitrification rate; SIN = substrate induced respiration.

 

Table 6. Values of soil characteristics for the recommended Australian reference soil to be used to normalise toxicity data

Soil property

Value

pH

6

Clay (%)

10

CEC (cmolc/kg)

10

OC (%)

1          

 

3.5              Sensitivity of organisms to zinc

The toxicity data (geometric means) used by the SSD method to calculate the ACL is shown in Table 2 for soil processes, Table 3 for soil invertebrates and Table 4 for plants. Figure 3 shows the SSD (that is, a cumulative distribution of the geometric means of the species) for all species for which there was Zn toxicity data. Toxicity data for plants, soil processes and soil invertebrates was evenly spread in the SSD, which indicates that these groups of organisms all have a similar sensitivity to Zn. Therefore, all the toxicity data was used to derive the ACLs, thus increasing the quantity of data used in the SSD method and increasing the reliability of the ACL values.

Figure 3. The species sensitivity distribution (plotted as a cumulative frequency against added zinc (Zn) concentration) for soil processes, soil invertebrates and plant species to Zn.

 

3.6              Calculation of soil quality guidelines for fresh zinc contamination

Soil quality guidelines were derived for fresh zinc contamination using three different sets of toxicity data: NOEC and EC10; LOEC and EC30; and EC50. The methods by which they were calculated and the resulting ACL and SQG values are presented in the following sections.

3.6.1        Calculation of soil quality guidelines for fresh zinc contamination based on no observed effect concentration and 10% effect concentration toxicity data

3.6.1.1       Calculation of soil-specific added contaminant limits

The NOEC and EC10 toxicity data were normalised using the equations presented in Table 5 to the Australian reference soil (Table 6) and then the lowest geometric mean for each species/soil microbial process was entered into the BurrliOZ species sensitivity distribution (Campbell et al. 2000) method. The SSD generated a single numerical value (that is, the ACL(NOEC & EC10) for each desired level of protection. These ACL(NOEC & EC10) values only apply to the Australian reference soil.

 

The ACL(NOEC & EC10) value for the Australian reference soil with an urban residential land/public open space use was approximately 100 mg/kg. These ACL(NOEC & EC10) values for the reference soil were then used to calculate ACL(NOEC & EC10) values for a range of soils (that is, soil-specific ACL(NOEC & EC10)) for each group of organisms using the same normalisation relationships as before but in the reverse manner. The following explains how the soil-specific ACL(NOEC & EC10) values for soils with an urban residential /public open space land use were calculated as an example of how this was done for each of the land uses.

 

Soil-specific ACL(NOEC & EC10) values for soil processes varied with soil pH and ranged from 20 to 330 mg/kg added Zn for soils with pHs between 4 and 7.5 (Table 7). The soil-specific ACL(NOEC & EC10) values for invertebrates (Table 8) varied with cation exchange capacity (CEC), with values ranging from 60 to 420 mg/kg for soils with CEC values ranging from 5 to 60 cmolc/kg. Soil-specific ACL(NOEC & EC10) values for plants (Table 9) were pH- and CEC- specific and ranged from 20 to 910 mg/kg for soils with pHs between 4 and 7.5 and CEC values between 5 and 60 cmolc/kg.

 

Table 7. Soil-specific ACL values for zinc (Zn) based on no observed effect concentration and 10% effect concentration toxicity data that should theoretically protect 80% of soil processes in soils with pH values ranging from 4.0 to 7.5.

Soil pH

Zn ACL (mg/kg)

for soil processes

4.0

20

4.5

30

5.0

45