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Assessment of Environmental Toxicity from Spent

Recycled Glass Abrasives Part A. Data Review

IETC Technical Report 01-99

Angie M. Obery

Wayne G. Landis

 

Institute of Environmental Toxicology and Chemistry

Huxley College of Environmental Studies

Western Washington University

Bellingham, Washington 98225

 

July 1, 1999

 

Prepared For:

Clean Washington Center

Division of Pacific Northwest Economic Region

999 Third Avenue, Suite #1060

Seattle, Washington 98104


ACKNOWLEDGMENTS

 

 

The Institute of Environmental Toxicology and Chemistry, Huxley College of Environmental Studies, at Western Washington University developed this review under contract No. 99-CWC-005 from the Clean Washington Center.

The Institute of Environmental Toxicology and Chemistry would like to acknowledge the large number of individuals who provided extensive direction and information throughout the project. Individuals from private and public sectors volunteered time and information on abrasives, coatings, and analytical services. In particular, special thanks to Fred Miller of TriVitro, Inc. for encouraging this data review and Mr. Mark Greskevitch of the National Institute for Occupational Safety and Health for providing vast amounts of research data on abrasives. Additional acknowledgment is extended to all governmental and private shipyards and bridge repair specialists for sharing historical analytical test results.


TABLE OF CONTENTS

1.0 Introduction

2.0 background

3.0 classification of waste

3.1 Solid Waste

3.2 Dangerous Waste

4.0 ABRASIVES

4.1 Crushed Glass

4.2 Copper Slag

4.3 Nickel Slag

4.4 Silica Sand

4.5 Coal Slag

5.0 Analytical Sampling

5.1 Total Metals and Toxicity Characteristic Leaching Procedure

5.2 Washington State Toxicity Test

5.2.1 Book Designation Procedure

5.2.2 Aquatic Bioassays

6.0 Conclusions and Recommendations

7.0 REFERENCES


LIST OF TABLES

Table 1 Method A Cleanup Levels for Soils

Table 2 Toxicity Characteristics List

Table 3 Comparisons of Pre-blast Crushed Glass Abrasive Constituents to Toxicity Criteria

Table 4 Comparisons of Spent Crushed Glass Abrasive Constituents to Toxicity Criteria

Table 5 Comparison of Pre-Blast Copper Slag Abrasive Constituents to Toxicity Criteria

Table 6 Comparison of Spent Copper Slag Abrasive Constituents to Toxicity Criteria

Table 7 Comparison of Pre-Blast Nickel Slag Abrasive Constituents to Toxicity Criteria

Table 8 Comparison of Pre-Blast Silica Sand Abrasive Constituents to Toxicity Criteria

Table 9 Comparison of Spent Silica Sand Abrasive Constituents to Toxicity Criteria

Table 10 Comparison of Pre-Blast Coal Slag Abrasive Constituents to Toxicity Criteria

Table 11 Environmental Analytical Laboratories

Table 12 General Price List

Table 13 Washington Toxicity Criteria


LIST OF FIGURES

Figure 1 Decision Making Framework for Spent Glass Abrasives Disposal

Figure 2 Relative Percent of Criteria of Pre-Blast Abrasives Constituents

Figure 3 Relative Percent of Criteria of Spent Abrasive Constituents


LIST OF APPENDICES

Appendix A Statistical Summaries for Spent Abrasive

Appendix B Washington State Department of Ecology "20 to 1" Letter


LIST OF ACRONYMS

CAS # Chemical Abstract Service Registry Number

CWC Clean Washington Center

DW Dangerous waste

EHW Extremely hazardous waste

mg/kg Milligram per kilogram

mg/L Milligram per liter

MW Mixed waste

NIOSH National Institute for Occupational Safety and Health

RCRA Resource Conservation Recovery Act

SSL Soil Screening Level

TCLP Toxicity characteristic leaching procedure

USEPA U.S. Environmental Protection Agency

WADOE Washington State Department of Ecology

WSDOT Washington State Department of Transportation

 


1.0 Introduction

 

The use of crushed recycled glass for abrasives is an area of growing interest by the glass recycling industry. As the popularity of recycling programs increases, the amount of recycled glass products increases as well. Developing new consumer markets for recycled glass products becomes increasingly important with the market supply. Without sufficient demand for recycled products, they are landfill bound. Fortunately, data from tests conducted by AERCO, Inc. of Lynwood, WA, indicate that abrasives manufactured from recycled glass are competitive in the industrial marketplace (CWC 1998). Additionally, the AERCO study showed that glass abrasives yield an acceptable profile for anchoring new coatings and resist rust for an extended period of time while maintaining dust generation within the acceptable limits set by the Air Resources Board of California.

The original objective of this data review was to classify certain types of spent glass abrasive according to their toxicity characteristics to be used in exempting waste according to WAC173-303-072(6). In order to build a dataset for the analysis we contacted a variety of facilities across the United States dealing with waste from the blasting and coating industry. We received data from several of the facilities, but in some cases the data were not suitable for analysis. The dataset used in this study is derived from five sets of data from several different types of facilities.

Variation among types of coatings, historical applications, and lack of supporting toxicity tests prevent toxicity classification of coatings at the present time. Our review of spent abrasive analytical results based on our current dataset indicates no correlation among each spent abrasive and elevated metal detection in spent abrasives. We conclude that elevated constituents found in the spent abrasive are due to elevated levels in the coating being removed. In this report we discuss the ranges of toxicants in spent abrasives and the relationship of toxicity characteristics in the coatings to the toxicity effects of the spent abrasive. A master compilation of toxicity tests on spent glass abrasives according to the type of coating should be compiled for possible exemption of waste in future years. This review is limited to disposal applications in Washington State.

This report contains six sections. Section 1 is this Introduction. Section 2 provides a brief summary of background information on spent abrasives including market advantages of crushed glass abrasives and a summary of current disposal procedures. Washington State regulations for disposing of abrasives are provided in Section 3. Section 4 includes a data review of pre-blasting and post-blasting constituents from a range of common abrasives used in the blasting and coating industries. Section 5 provides testing requirements for spent abrasives in the State of Washington. Section 6 provides conclusions and recommendations for disposal of spent glass abrasives.

 


2.0 Background

 

Crushed recycled glass abrasives are fairly new to the industry of abrasives and offers a range of advantages over traditional media. Recycled glass abrasives have a number of market advantages including:

Pre-blast glass abrasives have the unique characteristic of containing at the most trace levels of heavy metals compared to other traditional slag abrasives. Thus, the toxicity of the pre-blast glass abrasives does not pose a threat to human health or the environment. Tests performed on virgin materials do not adequately indicate the properties of the spent material. Depending on the type of coating removed, toxicity characteristics of the spent abrasive will vary accordingly.

The economics of recycling currently makes recycling attractive for a limited number of materials (USEPA 1994). Markets for crushed recycled glass have developed over time to facilitate the consolidation of materials into quantities that are worth handling and that allow for economies of scale in collection and processing. Using crushed recycled glass as an abrasive material has developed into a profitable and environmentally friendly alternative (USEPA 1992).

No specific regulations exist for spent glass abrasive waste and thus this waste falls under general regulations for spent abrasives. In the State of Washington, spent abrasives are considered solid waste or dangerous waste depending on the testing results. The generator of the waste is responsible for determining if the waste possesses hazardous characteristics. This is a necessary step in determining the disposal and reuse options available. Washington regulations require that a Toxicity Characteristic Leaching Procedure (TCLP) test be performed to determine if the material is dangerous. These tests are conducted in accordance with 40 CFR Part 261 and WAC 173-303-090 subsection 8. If the waste is determined to be dangerous, the material must be managed accordingly. If the waste is determined not to be dangerous, the grit is considered a solid waste. In the State of Washington, dangerous wastes are those solid wastes designated in WAC 173-303 as dangerous waste (DW), extremely hazardous waste (EHW), or mixed waste (MW). Hazardous wastes are those solid wastes designated by 40 CFR Part 261 and regulated as hazardous and/or mixed wastes by the USEPA. A state-only dangerous waste is a waste designated only by WAC 173-303 and is not regulated as a hazardous waste under 40 CFR 261. Under Washington regulations, an extremely hazardous waste is always a hazardous waste according to 40 CFR 261, but the inverse is not always true. Some hazardous waste under 40 CFR will be deemed dangerous waste while others will be extremely hazardous waste according to WAC 173-303.

According to Washington regulations, non-dangerous glass abrasive blasting grit waste can be disposed of in a solid waste landfill. Preferably, spent glass abrasives should be recycled when feasible. A number of recycling options are available and include using grit as fill material in construction projects, as road base materials, and in asphalt [i.e., glassphalt (CWC 1994)].

 


3.0 Classification of Wastes

 

3.1 Solid Waste

Solid wastes are designated under WAC 173-303 and WAC 173-304. Solid wastes are all putrescible and nonputrescible solid and semi-solid waste including, but not limited to, garbage, rubbish, ashes, industrial wastes, swill, demolition and construction wastes, and vehicles. Putrescible waste is solid waste that contains materials capable of being decomposed by micro-organisms.

Within the category of solid waste, inert wastes are singled out individually. Inert waste is defined as noncombustible, nondangerous solid wastes that are likely to retain their physical and chemical structure under expected conditions of disposal, including resistance to biological attack and chemical attack from acidic rainwater. Currently, the definition of inert waste is undergoing clarification and is expected to be revised in the new set of solid waste regulations to be released in 2000. In the interim, the basic rule for categorizing inert waste is to screen the results of the Resource Conservation Recovery Act (RCRA) total metals analyses, Method 6010, against the Model Toxics Control Act Method A Cleanup Levels for soil (WAC 173-340-740) (WADOE 1996). These soil screening levels are based on a residential exposure and are groundwater protective. Table 1 provides Washington State's Model Toxics Control Act Method A Cleanup Levels for soil. The Washington State Department of Ecology requires any recycling facility utilizing spent abrasives to periodically test the finished product under method 1610 (phone conversation with Don Seeberger, Dept of Ecology NWRO, December 15, 1998).

3.2 Dangerous Waste

In the State of Washington, dangerous wastes are those solid wastes designated in WAC 173-303 as DW, EHW, or MW. To determine if a waste is primarily designated as dangerous, one of the four following criteria must be true.

(1) Waste is a listed discarded chemical product (WAC 173-303-081)

(2) Waste is a listed dangerous waste source (WAC 173-303-082)

(3) Waste exhibits dangerous waste characteristics (WAC 173-303-090)

(4) Waste exceeds dangerous waste criteria (WAC 173-303-100)

Spent abrasives usually are not listed as discarded chemical products (criteria 1) or dangerous waste sources (criteria 2), but are required to be sampled for exhibiting dangerous waste characteristics (i.e., criteria 3 above) and/or exceeding dangerous waste criteria (i.e., criteria 4 above).

The Institute of Toxicology and Chemistry (IETC) at Western Washington University developed a decision-making framework for spent glass abrasive disposal according to current Washington disposal regulations (Figure 1). Some blasting operations may have prior knowledge of potentially harmful constituents on surfaces to be blasted. If knowledge is sufficient and historical tests have illustrated that the coating is acceptable for disposal in a solid waste landfill, no further testing is required. Under these circumstances, the regulatory agency or office may issue a long-term waste disposal authorization. When insufficient knowledge exists regarding the type of coating, spent abrasives must be tested for leachability and toxicity characteristics using the toxicity tests discussed in Section 5. If TCLP results exceed the TCLP criteria listed in Table 2, the waste is considered dangerous (Ty Thomas, Dept of Ecology Olympia Headquarters, phone conversation with F. Miller, 6/10/99). When spent abrasives are only used on one type of coating or coating system, a single set of tests (i.e., RCRA Total Metals, and if necessary, TCLP and fish bioassays) on representative samples of the spent abrasives should be sufficient for toxicity characterization requirements as long as operation procedures remain constant and are recorded.


4.0 Abrasives

 

This section describes the ranges of constituents found in common forms of pre-blast and spent abrasives used in the blasting and coating industries. The following 11 metals were evaluated for total metal content in pre-blast abrasives: arsenic, beryllium, cadmium, chromium, lead, manganese, nickel, silver, titanium, vanadium, and zinc. Predicted metal concentration ranges for pre-blast copper slags, nickel slags, silica sand, and coal slags were generated during a National Institute for Occupational Safety and Health (NIOSH) investigation conducted by KTA-Tator, Inc. in 1995-1998). These tests were conducted prior to blasting any materials and provide the elevated levels of constituents prior to use as an abrasive. Predicted concentration ranges for crushed glass abrasives were generated from a TriVitro analysis on pre-blast materials and from the NIOSH report. Predicted concentrations of metals found in spent copper slags, silica sand, coal slags, and glass abrasives were compiled from analytical results submitted to the Institute by various private and government offices who use or manage spent abrasives.

For each type of abrasive, two comparison tables were generated; a comparison of pre-blast abrasive constituents and a comparison of spent abrasives. The comparison of pre-blast abrasives included an evaluation of up to 14 heavy metal constituents: arsenic, barium, beryllium, cadmium, chromium, lead, manganese, mercury, nickel, selenium, silver, titanium, vanadium, and zinc. Pre-blast data were compiled from total metals analyses on a weight by weight basis (milligram of analyte per kilogram of pre-blast material). Thus, comparisons of the pre-blast abrasive data were made to total metals analyses screening criteria. The screening criteria for pre-blast abrasive constituents included an adjusted TCLP criterion according to the 20 to 1 Rule (20:1 dilution factor applied to the total metals analysis against the TCLP criteria. See Section 5.1 for further details) and a generic soil screening level (SSL) provided by USEPA (WADOE 1992) (USEPA 1996). USEPA SSLs are commonly used as a risk-based tool for accelerated evaluations of contaminated soils with anticipated future residential land use scenarios protective of groundwater. SSLs are not national cleanup standards and alone do not define "unacceptable" levels of contaminants in soil. They are provided only as screening levels to define contaminants that do not require further federal attention (USEPA 1996). The comparison of spent abrasives included an evaluation of the following 10 metals from their TCLP analytical results for their potential to leach into groundwater and exceed a groundwater protective concentration: arsenic barium, cadmium, chromium, copper, lead, mercury, selenium, silver, and zinc. For all test results, the high and low concentrations detected in the pre-blast and spent abrasives are provided for each type of abrasive. Statistical summaries for spent abrasive TCLP analytical results are provided in Appendix A.


Table 1 Method A Cleanup Levels for Soilsa

 

Constituent

 

CAS Number

 

Cleanup Level (mg/kg)

Arsenic

7740382

20.0

Benzene

71432

0.5

Cadmium

7440439

2.0

Chromium

7440473

100

DDT

50293

1.0

Ethylbenzene

100414

20.0

Ethylene dibromide

106934

0.001

Lead

7439921

250.0

Lindane

58899

1.0

Methylene Chloride

75092

0.5

Mercury (inorganic)

7439976

1.0

PAHs (carcinogenic)

1.0

PCBs Mixtures

1.0

Tetrachloroethylene

127184

0.5

Toluene

108883

40.0

TPH (gasoline)

100.0

TPH (diesel)

200.0

TPH (other)

200.0

1,1,1 Trichloroethane

71556

20.0

Trichloroethylene

79015

0.5

Xylenes

1330207

20.0

Source: WAC 1996

a Refer to WAC 173-340-740 Table 2 Method A Cleanup Levels Soils for a complete listing of footnotes.

CAS = Chemical Abstract System Registry Number


Table 2 TCLP Criteria

Maximum Concentrations of Contaminants for the Toxicity Characteristics

 

Constituent

 

CAS #

Dangerous Waste (DW) (mg/L)

Arsenic

7440382

5.0

Barium

7440393

100

Benzene

71432

0.5

Cadmium

7440439

1.0

Carbon Tetrachloride

56235

0.5

Chlordane

57749

0.03

Chlorobenzene

108907

100.0

Chloroform

67663

6.0

Chromium

7440473

5.0

o-Cresol

95487

200.0

m-Cresol

108394

200.0

p-Cresol

106445

200.0

Cresol

NA

200.0

2,4-D

94757

10.0

1,4-Dichlorobenzene

106467

7.5

1,2-Dichloroethane

107062

0.5

1,1-Dichloroethylene

75354

0.7

2,4-Dinitrotoluene

121142

0.13

Endrin

72208

0.02

Heptachlor (and its epoxide)

76448

0.008

Hexachlorobenzene

118741

0.13

Hexachlorobutadiene

87683

0.5

Hexachloroethane

67721

3.0

Lead

7439921

5.0

Lindane

58899

0.4

Mercury

7439976

0.2

Methoxychlor

72435

10.0

Methyl ethyl ketone

78933

200.0

Nitrobenzene

98953

2.0

Pentachlorophenol

87865

100.0

Pyridine

110861

5.0

Selenium

7782492

1.0

Silver

7440224

5.0

Tetrachlorethylene

127184

0.7

Toxaphene

8001352

0.5

Trichloroethylene

79016

0.5

2,4,5-Trichlorophenol

95954

400.0

2,4,6-Trichlorophenol

88062

2.0

2,4,5-TP (Silvex)

93721

1.0

Vinyl Chloride

75014

0.2

Source: WADOE 1998.

TCLP = Toxicity characteristic leaching procedure


Figure 1 Current Decision Making Framework for Spent Glass Abrasives Disposal

flowdiagram.gif


4.1 Crushed Glass

A trade name for crushed recycled glass abrasives is VitroGrit™. Crushed glass abrasives mostly are derived from recycled glass products. Many different types of mesh grades and quality standards are available in glass abrasives. Like silica sand, no elevated constituents are commonly found in the media as presented in Table 3. Thus, the data support the conclusion that spent glass abrasives only contain the materials blasted plus the inert, non-heavy metal components of recycled glass.

Table 4 provides a comparison of constituents found in spent glass abrasives to TCLP criteria provided under 40 CFR Part 261 and WAC 173-303-090 subsection 8. From the dataset collected, no constituents exceed TCLP criteria for spent glass abrasives. Therefore, the elevated level of constituents found in glass abrasives is due to the type of coating removed with the abrasive.

4.2 Copper Slag

Copper slags are by-products of the copper smelter industry. Trade names of copper slags include Kleen Blast and Tru-Grit. Copper slag, like all slags, have the advantage of low crystalline silica content but have been documented to contain other hazardous contaminants (USEPA 1997 NIOSH 1998). Table 5 provides comparisons of constituents found in pre-blast copper slags to Washington State adjusted dangerous waste criteria (i.e., TCLP according to 20 to 1 Rule). This table illustrates that prior to blasting, copper slags have a potential to exceed dangerous waste criteria. Elevated levels of arsenic, chromium, and lead are possible for copper slag. Because of the limited number of screening criteria for metals by the State of Washington, ranges of constituents were also compared against the USEPA generic soil screening levels for migration to groundwater (USEPA 1996). The predicted concentration range for copper slags exceeds the USEPA generic soil screening levels for arsenic, cadmium, and chromium.

Comparisons of constituents found in spent copper slags to TCLP criteria provided under 40 CFR Part 261 and WAC 173-303-090 subsection 8 are provided in Table 6. In our dataset, no constituents exceeded TCLP criteria for spent copper slags. Note that copper is not regulated under 40 CFR Part 261 and WAC 173-303-090 subsection 8 TCLP criteria.

4.3 Nickel Slag

Trade names for nickel slags include Green Diamond and Kayway. Table 7 provides a comparison of constituents found in nickel slag to Washington State adjusted dangerous waste criteria (i.e., TCLP according to 20 to 1 Rule). This table illustrates that prior to blasting, nickel slags have the potential to exceed dangerous waste criteria for chromium. In addition, the predicted concentration range for nickel slag exceeds the USEPA generic soil screening levels for chromium and nickel. Although typically not analyzed, many nickel slags contain nickel and chrome (NIOSH 1998).

Comparisons of constituents found in nickel slags to TCLP criteria were not conducted due to insufficient data.


Table 3 Comparison of Pre-Blast Crushed Glass Abrasive Constituents to Toxicity Criteria

 

 

Common Spent Abrasives Constituents

Washington State Dangerous Waste Criteria Adjusted According to 20 to 1 Rule (mg/kg)

 

USEPA SSLs for Migration to Groundwater (mg/kg)b,1

 

 

Predicted

Concentration (mg/kg)c

 

 

High and Low

Concentrations

(mg/kg)d

Arsenic

100

29

0.25

<2.231 - <2.808

Barium

NA

1,600

NA

<0.048 - <0.056

Beryllium

NA

63

0.02

NA

Cadmium

20

8

0.01

<0.097 - <0.112

Chromium (VI)

100

38

1

<0.243 - <0.280

Lead

100

NA

6.3

<1.215 - <1.404

Manganese

NA

NA

0.66

NA

Mercury

NA

2

NA

<0.048 - <0.056

Nickel

NA

130

1

<0.486 - <0.561

Selenium

NA

5

NA

<0.048 - <0.056

Silver

100

34

0.15

<0.145 - <0.168

Titanium

NA

NA

0.25

NA

Vanadium

NA

6,000

0.15

NA

Zinc

NA

12,000

NA

<0.224 - < 2.431

Note: no predicted values exceed the screening criteria.

1 Values are for a 20 dilution attenuation factor.

SSL = U.S. EPA generic soil screening levels.

Sources: a = WADOE 1996, b = USEPA 1996, c = NIOSH 1998, d = NVL 1997.


Table 4 Comparison of Spent Crushed Glass Abrasive Constituents to Toxicity Criteria

 

Common Spent Abrasives Constituents

 

TCLP Criteria (mg/L)a

High and Low

Concentrations

(mg/L)b

Arsenic

5.0

ND

Barium

100

0.06-0.71

Cadmium

0.5

ND-0.06

Chromium

5.0

ND-0.06

Copper

NA

0.5-3.66

Lead

5.0

ND-1.01

Mercury

0.2

ND

Selenium

1.0

ND-0.34

Silver

5.0

ND

Zinc

NA

ND-7.67

NA = Not available

ND = Not Detected

TCLP = Toxicity Characterization Leaching Procedure

Sources: a = WADOE 1998, b =IETC assembled dataset


Table 5 Comparisons of Pre-Blast Copper Slag Abrasive Constituents to Toxicity Criteria

 

 

Common Spent Abrasives Constituents

Washington State Dangerous Waste Criteria Adjusted According to 20 to 1 Rule (mg/kg)a

USEPA SSLs for Migration to Groundwater (mg/kg)b,1

 

High and Low Concentrations

(mg/kg)c

Arsenic

100

29

6 - 405

Beryllium

NA

63

0.4 - 1.4

Cadmium

20

8

0.2 - 8.3

Chromium (VI)

100

38

7 - 158

Lead

100

NA

2 - 850

Manganese

NA

NA

20 - 2400

Nickel

NA

130

1.8 - 28

Silver

100

34

0.15 - 5.25

Titanium

NA

NA

155 - 130

Vanadium

NA

6,000

5.95 - 94

Zinc

NA

12,000

NA

* Red constituents indicate predicted range exceeds criteria.

1 Values are for a 20 dilution attenuation factor

SSL = U.S. EPA generic soil screening levels

Sources: a = WADOE 1996, b = USEPA 1996, c = NIOSH 1998


Table 6 Comparison of Spent Copper Slag Abrasive Constituents to Toxicity Criteria

 

Common Spent Abrasives Constituents

 

TCLP Criteria (mg/L)a

High and Low

Concentrations

(mg/L)b

Arsenic

5.0

ND-0.09

Barium

100

0.3-4.1

Cadmium

0.5

ND-0.02

Chromium

5.0

ND-0.12

Copper

NA

NA

Lead

5.0

0.1-1.65

Mercury

0.2

ND-0.06

Selenium

1.0

ND-0.12

Silver

5.0

ND

Zinc

NA

NA

NA = Not available

ND = Not Detected

TCLP = Toxicity Characterization Leaching Procedure

Sources: a = WADOE 1998, b = IETC assembled dataset


Table 7 Comparisons of Pre-Blast Nickel Slag Abrasive Constituents to Toxicity Criteria

 

Common Spent Abrasives Constituents

Washington State Dangerous Waste Criteria Adjusted According to 20 to 1 Rule (mg/kg)a

USEPA SSLs for Migration to Groundwater (mg/kg)b,1

 

High and Low Concentrations (mg/kg)c

Arsenic

100

29

0.25 - 15

Beryllium

NA

63

0.047 - 0.28

Cadmium

20

8

0.02 - 0.35

Chromium

100

38

120 - 400

Lead

100

NA

0.62 - 7.5

Manganese

NA

NA

97 - 150

Nickel

NA

130

640 - 660

Silver

100

34

0.15

Titanium

NA

NA

13 - 150

Vanadium

NA

6,000

4.2 - 13

Zinc

NA

12,000

NA

* Red constituents indicate predicted range exceeds criteria.

1 Values are for a 20 dilution attenuation factor

SSL = U.S. EPA generic soil screening levels

Sources: a = WADOE 1996, b = USEPA 1996, c = NIOSH 1998


4.4 Silica Sand

Sand is the most archaic of the blast media but was included in the review for comparisons only. Sand is typically not used in blasting operations due to its production of hazardous dust affecting the health and safety of workers. Sand is rough on the substrate and is nearly impossible to segregate from the coatings after cleaning (NIOSH 1998). If the hazardous materials from coatings are mixed with the sand, the end result is a large amount of hazardous waste due to the inability to separate the reusable abrasives from the spent abrasives with coatings. Advantages of sand are that it is cheap and, as illustrated in Table 8, no elevated toxic constituents are commonly found in the pre-blast media.

Comparisons of constituents found in spent sand abrasives to TCLP criteria provided under 40 CFR Part 261 and WAC 173-303-090 subsection 8 are provided in Table 9. From the dataset collected, lead and chromium detected concentrations exceed TCLP criteria for spent sand abrasives. Once again, the elevated level of constituents found in sand abrasives is strongly correlated to the type of coating removed with the abrasive.

4.5 Coal Slag

Trade names for coal slag include Harsco Black Beauty and Target Black Pearl. Coal slag consists of crushed slag from coal-fired utility boilers and is used by numerous industries in abrasive operations. Table 10 provides a comparison of constituents found in coal slag to Washington State adjusted dangerous waste criteria (i.e., TCLP according to the 20 to 1 Rule). This table illustrates that prior to blasting no constituents exceed dangerous waste criteria. However, the predicted concentration range for coal slag slightly exceeds the USEPA generic soil screening level for chromium.

Comparisons of constituents found in coal slag to TCLP criteria were not conducted due to insufficient data collection on spent coal slag.


Table 8 Comparisons of Pre-Blast Silica Sand Abrasive Constituents to Toxicity Criteria

 

 

 

Common Spent Abrasives Constituents

Washington State Dangerous Waste Criteria Adjusted According to 20 to 1 Rule (mg/kg)a

USEPA SSLs for Migration to Groundwater (mg/kg)b,1

 

High and Low

Concentrations (mg/kg)c

Arsenic

100

29

0.2 - 1.5

Beryllium

NA

63

0.01 - 0.074

Cadmium

20

8

0.02 - 0.35

Chromium

100

38

1 - 3.7

Lead

100

NA

0.2 - 0.89

Manganese

NA

NA

0.13 - 88

Nickel

NA

130

1 - 3

Silver

100

34

0.15

Titanium

NA

NA

2.7 - 82

Vanadium

NA

6,000

0.15 - 6

Zinc

NA

12,000

NA

Note: no predicted values exceed the screening criteria.

1 Values are for a 20 dilution attenuation factor.

SSL = U.S. EPA generic soil screening levels.

Sources: a = WADOE 1996, b = USEPA 1996, c = NIOSH 1998.


Table 9 Comparison of Spent Silica Sand Abrasive Constituents to Toxicity Criteria

 

Common Spent Abrasives Constituents

 

TCLP Criteria (mg/L)a

High and Low

Concentrations

(mg/L)b

Arsenic

5.0

ND-0.1

Barium

100

0.12-1.6

Cadmium

0.5

ND-1.1

Chromium

5.0

ND-0.84

Copper

NA

NA

Lead

5.0

ND-5.7

Mercury

0.2

ND

Selenium

1.0

ND-0.05

Silver

5.0

ND-0.03

Zinc

NA

NA

* Red constituents indicate predicted range exceeds criteria.

NA = Not available

ND = Not Detected

TCLP = Toxicity Characterization Leaching Procedure

Sources: a = WADOE 1998, b = IETC assembled dataset


Table 10 Comparisons of Pre-Blast Coal Slag Abrasive Constituents to Toxicity Criteria

Common Spent Abrasives Constituents

Washington State Dangerous Waster Criteria Adjusted According to the 20 to 1 Rule (mg/Kg)a

USEPA SSLs for Migration to Groundwater (mg/Kg) b,1

High and Low

Concentrations (mg/kg)c

 

Arsenic

100

29

0.05-2.1

Beryllium

NA

63

0.28 - 6.3

Cadmium

20

8

0.01 - 0.35

Chromium

100

38

1 - 55

Lead

100

NA

0.53 - 6.8

Manganese

NA

NA

6 - 240

Nickel

NA

130

1 - 44

Silver

100

34

0.15 - 0.62

Titanium

NA

NA

58 - 2000

Vanadium

NA

6,000

30 - 100

Zinc

NA

12,000

Note: no predicted values exceed the adjusted Washington State Dangerous Waste Criteria.

* Red constituents indicate predicted range exceeds criteria.

1 Values are for a 20 dilution attenuation factor

SSL = U.S. EPA generic soil screening levels

Sources: a = WADOE 1996, b = USEPA 1996, c = NIOSH 1998


5.0 Analytical Sampling

 5.1 Total Metals and TCLP

The eight RCRA total metals analyses (Method 6010) can be used as a screening test to determine if the waste could potentially fail the TCLP test. This test is often logical for industries because the cost of testing for total metals is significantly less than the cost of doing a TCLP analysis. Washington State Department of Ecology (WADOE) accepts a 20:1 dilution factor (i.e., commonly referred to as the "20 to 1 Rule") applied to the total metals analysis and screened against the TCLP criteria (WADOE 1992). Appendix B provides the letter stating the rule. This rule simply states that if a total metal concentration is less than 20 times the TCLP criteria, than the sample could not fail the TCLP for a particular metal because a 20:1 dilution factor is built into the TCLP test procedure. Thus, TCLP values are diluted by multiplying by 20 then are screened against the total metals analyses. If the diluted total metals do not exceed their respective TCLP criteria, no further evaluation is necessary and spent glass abrasive should be disposed of in a solid waste landfill. In addition, the total metals analyses can be used to define inert waste as discussed in Section 3.1. Table 11 provides a list of laboratories that perform total metals analyses. This list is not comprehensive and is only provided for planning purposes. Prices for the total metals analyses are provided in Table 12 for several laboratories.

Prior to disposing waste in a landfill, a TCLP test, Method 1311 must be performed unless the total metals analyses do not exceed the 20 to 1 Rule. The TCLP test determines the leachability of the constituents in the waste. Wastes predicted to be leachable using the TCLP test method are subject to WAC 173-303 dangerous waste regulations and must be disposed of in a properly lined landfill. If the results of the TCLP are equal to or exceed the criteria in Table 2, the waste is designated as dangerous. One exception is waste that fails the TCLP screen for chromium only when chromium is exclusively or nearly exclusively trivalent chromium. Under this exception the waste should be designated solid waste. Table 11 provides a list of laboratories that perform TCLP analyses. This list is not comprehensive and is only provided for planning purposes. Prices for TCLP are provided in Table 12 for several laboratories.

5.2 Washington State Toxicity Test

The Washington State dangerous waste regulations state that for unknown constituents, a fish or rat bioassay must be completed prior to disposal determination. The regulations offer two options for fulfilling this requirement: a book designation procedure and a bioassay. The following discussion related to toxicity testing is limited to fish bioassays as specified by current regulations. Other bioassays may be less expensive and predictive of environmental effects but development for this applications will be necessary. Such tests include the 48 Daphnia magna acute toxicity test (APHA 8711)or the echinoderm fertilization assay (APHA 8810).

5.2.1 Book Designation Procedure

If desired, a waste can be assessed to determine if it meets the toxicity criteria by following a book designation procedure. However, when using this method, the major constituent in the waste must be known. In this method, the toxic category for each known constituent is determined. Toxic categories for constituents may be determined from available data or by obtaining data from the NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) and checking these data against the toxic category table (Table 13).

If data are available for more than one of the toxicity criteria (fish, oral, inhalation, or dermal), then the data indicating severest toxicity must be used and the most acutely toxic category must be assigned to the constituent. If the NIOSH RTECS or other data sources do not agree on the same category, then the category using NIOSH RTECS should be used. When toxicity data for a constituent cannot be found in the NIOSH RTECS or other readily available sources, the toxic category need not be determined for that constituent.

The equivalent concentration for the waste form is determined using the following formula:

,

where:

·(X, A, B, C, or D)% is the sum of all the concentrations percentages for a particular toxic category.


Table 11 Environmental Analytical and Toxicity Testing Laboratories

Name of Laboratory

Address/Phone

Total Metals

TCLP

Fish Bioassays

Analytical Chemistry

404 9th Avenue N.

Seattle, WA 98109-4708

Phone: 206-622-8353

Fax: 206-622-4623

 

 

4

 

 

4

Analytical Sciences Laboratory

Holm Research Center

University of Idaho

Moscow, ID 83844-2203

Phone: 208-885-7081

Fax: 208-885-8937

 

 

4

 

 

4

 

 

 

AmTest Laboratories

14603 N.C. 87th St.

Redmond, WA 98052

Phone: 425-885-1664

Fax: 425-883-3495

 

 

4

 

 

4

 

 

4

B & P Laboratories, Inc.

5635 Delridge Way S.W.

Seattle, WA 98106

Phone: 206-937-3644

 

 

4

 

 

4

Cascade Analytical, Inc.

3019 G.S. Center Rd.

Wenatchee, WA 98801

Phone: 800-545-4206

Fax: 509-62-8183

 

 

4

 

 

4

Parametrix

5808 Lake Washington Blvd N.E

Suite 200

Kirkland, WA

Phone: 425-822-8880

Fax: 425-889-8808

 

 

4

Philip Environmental Laboratory

955 Powell Avenue S.W.

Renton WA 98055

Phone: 425-227-6110

Fax: 425-227-6196

 

 

4

 

 

4

Spectra Laboratories, Inc.

2221 Ross Way

Tacoma, WA 98421

Phone: 253-272-4850

Fax: 253-572-9839

 

 

4

 

 

4

*This list is not comprehensive and is provided for planning purposes only.


Table 12 General Price List for Analytical and Toxicological Services

Company

Parameter

Method

Price

Analytical Chemistry

Total RCRA metals

EPA 6010

$200.00

TCLP RCRA metals

EPA 1311/6010

$150.00

Analytical Sciences Laboratory

Total RCRA metals

EPA 6010

$58.00

TCLP RCRA metals

EPA 1311/6010

$161.00

AmTest Laboratories

Total RCRA metals

EPA 6010

$60.00

TCLP RCRA metals

EPA 1311/6010

$110.00

Fish Bioassay

WADOE 80-12

$500.00

B & P Laboratories, Inc.

Total RCRA metals

EPA 6010

$128.00

TCLP RCRA metals

EPA 1311/6010

$150.00

Cascade Analytical, Inc.

Total RCRA metals

EPA 6010

$140.00

TCLP RCRA metals

EPA 1311/6010

$130.00

Parametrix

Fish Bioassay, Dangerous Waste Designation

WADOE 80-12

$650.00

Fish Bioassys, Extremely Hazardous Waste

WADOE 80-12

$750.00

Philip Services Laboratory

Total RCRA metals

EPA 6010

$75.00

TCLP RCRA metals

EPA 1311/6010

$150.00

Spectra Laboratories, Inc

Total RCRA metals

EPA 6010

$84.00

TCLP RCRA metals

EPA 1311/6010

$124.00

8 RCRA metals include: As, Ba, Cd, Cr, Pb, Se, Ag, Hg.

*Many prices are based on minimum number of samples. Often per unit costs are lower with an increased number of samples.

*This list is not comprehensive and is provided for planning purposes only.

 


Table 13 Washington Toxicity Categories

 

Toxic Categorya

 

Fish LC50 (mg/L)b

 

Oral (Rat) LD50 (mg/kg)

 

Inhalation (Rat) LC50 (mg/L)

 

Dermal (Rabbit) LD50 (mg/kg)

X

<0.01

<0.5

<0.02

<2

A

0.01 - <0.1

0.5 - <5

0.02 - <0.2

2 - <20

B

0.1 - <1

5 - <50

.2 - <2

20 - <200

C

1 - <10

50 - <500

2 - <20

200 - <2000

D

10 - < 100

500 - <5000

20 - <200

2000 - < 20,000

a Category X is the most toxic, category D is the least toxic.

b LC50 data must be from an exposure period of at least 24 hours. Salmonid data are preferred followed by fathead minnow data.


Waste is designated for toxicity according to the value of the equivalent concentration:

  • If the equivalent concentration is less than 0.001%, the waste is not a toxic dangerous waste; or
  • if the equivalent concentration is equal to or greater than 0.001% and less than 1.0%, the waste is DW and is assigned the dangerous waste number WT02; or
  • if the equivalent concentration is equal to or greater than 1.0%, the waste is EHW and is assigned the dangerous waste number WT01.

After completing the book designation procedure for toxicity, the waste generator has the option to either accept the results of the designation or conduct further toxicity assessment using aquatic bioassays.

5.2.2 Aquatic Bioassays

The Washington State Department of Ecology (WADOE) developed the acute fish toxicity test (Method 80-12) to determine if a waste meets the definition of dangerous waste in the Dangerous Waste Regulations, Chapter 173-303-110 (WADOE 1997). Method 80-12 provides a relatively simple and low-cost method for testing the toxicity of generated wastes. The method is used when the toxicity of a waste is unknown. The recommended fish bioassay is a static 96-hour test. This method determines if the sample waste LC50 is significantly less than or equal to the regulatory threshold of 100 mg/L for DW or 10 mg/L for EHW. The LC50 represents the median lethal concentration of waste that kills 50 percent of the test fish within 96 hours.

If the book procedure for assessing the toxicity of a waste is not feasible and the waste requires a toxicity assessment, the waste must be tested for dangerous waste designation using Method 80-12. The waste concentrations of 100 mg/L and 10 mg/L were selected to correspond with the definition of dangerous waste and extremely hazardous waste, respectively.

Table 11 provides a list of laboratories that perform fish bioassays. This list is not comprehensive and is provided for planning purposes only. Prices for bioassays are provided in Table 12 for the respective laboratories.

 

6.0 CONCLUSIONS AND RECOMMENDATIONS

 

Pre-blast glass abrasives have the unique characteristic of containing at the most only trace levels of heavy metals compared to other traditional slag abrasives. Pre-blast copper slags often contain elevated levels of arsenic, chromium, and lead as by-products from their previous use. Pre-blast nickel and coal slags may potentially have elevated levels of chrome, chromium, and nickel and chromium, respectively. Silica sand does not contribute pre-blast contaminants but exhibits hazardous dusts affecting the health and safety of workers. Figure 2 illustrates the relative percent of maximum detected concentrations of metals to the acceptable criteria (i.e., the lower of the adjusted WA dangerous waste criteria and the USEPA SSL for migration to groundwater). As shown in the figure, pre-blast glass abrasives did not contain any metals that exceed their respective criteria, whereas the pre-blast slag abrasives contained several metals that exceeded their respective criteria.

From the data review, we concluded that the physical characteristics of glass and other pre-blast abrasives do not solely depend upon the properties of the spent abrasive materials. Data results from the eight RCRA metals on glass and other spent abrasives showed that the types of coatings removed will drive the waste to exceed or not to exceed acceptable disposal criteria. Figure 3 illustrates the relative percent of maximum detected concentrations of metals in spent abrasives to the TCLP criteria. As shown in the figure, spent abrasive TCLP results indicate no relationship among each abrasive and elevated metal levels. Therefore, elevated constituents found in the spent abrasive are due to elevated levels in the removed coating. These results indicate that dangerous materials found in spent glass abrasives are those from the blasted coatings.

The review did not include any disposal categories for spent coatings. Numerous coating industries and institutions were contacted for information relating to disposal of spent coatings and they were unable to provide any further information in this area of research. However, from our discussions with experts in the coating industries, we concluded that current spent coatings could be categorized for disposal but historical coatings often lack consistency in content or proper application tracing documentation. Because of the numerous types of coatings available to shipyard and bridge repair industries, we recommend tracking analytical results from spent glass abrasives to the type of coating removed. When similar coatings are later removed, historical test results may be sufficient for revising disposal or recycling protocols.

We conducted a review of current state and federal regulations for spent abrasives. Spent glass abrasives were not singled out in any of the regulation reviewed. In Washington State, spent abrasives are considered solid waste or dangerous waste depending on the characterization results. Total metals analyses (i.e., Method 6010) can be used as a screening tool to determine if waste could potentially fail the TCLP test (i.e., Method 1311/6010). Often, the total metals analyses cost significantly less than TCLP analysis. However, a TCLP test must be conducted from a sample of the spent abrasive if it exceeds acceptable toxicity criteria for total metals prior to landfill disposal. IETC provided a decision-making framework for spent glass abrasive disposal according to current Washington disposal regulations. This framework is recommended to clarify the regulations for exactly when it is necessary to conduct bioassays.


Notes: Maximum detected concentration of each constituent was compared to the lowest screening criteria for total metals (See Section 4.0)


Notes: Maximum detected concentration of each constituent was compared to the lowest screening criteria for total metals (See Section 4.0)


A large amount of uncertainty exists with the quality of the data and the adequate characterization of toxicity from spent abrasives. A limited number of data results included respective quality assurance/quality control (QA/QC) analysis. It was assumed that adequate QA/QC samples were taken and proper data validation conducted. Where nondetects were reported for a constituent, the values defaulted to the method detection limit. In several cases, the entire range of constituents present in pre-blast and spent abrasives where derived from all nondetects. The use of method detection limits in the place of nondetects is a conservative approach in representing the actual range of constituents. However, all of the detection limits fell below the screening criteria. In addition, very few of the test results exceeded toxicity criteria for the metals and may not be representative of the overall data results. Since data collection was conducted solely on a volunteer basis, skewed data results toward lower concentrations are possible. A large amount of uncertainty remains in understanding the most realistic toxicity potential from spent abrasives. Simply comparing spent analytical results against TCLP criteria is not representative of actual toxicity to potential human and ecological receptors exposed to spent abrasives. For example, the extraction methods used to evaluate spent abrasive samples may remove from the abrasives quantities of chemicals greater than are available to human and ecological receptors. Toxicity tests have been proven to be more representative of actual toxicity potential.

Given the large amount of uncertainty of the data collected in this review and the inability to classify coatings removed by glass abrasives according to their toxicity potential, we recommend the development of a protocol that identifies types of coatings or blasting surfaces that would be exempt from hazardous waste characterization based on WAC 173-303-072(6). This protocol would set guidelines for tracking analytical results from spent glass abrasives to be applied for disposal requirements. As demonstrated in this review, toxicants present in spent glass abrasives are not due to the abrasive itself, but are mixed with the glass abrasive while removing toxic coatings or refurbishing heavy metal surfaces. Therefore, understanding the toxicity potential of typical coatings is essential to classifying the toxicity potential of spent abrasives. The protocol should include a method for data compiling, reporting, and submitting toxicity characteristics of coatings to the State of Washington for exception under WAC 173-303-072(6).

7.0 REFERENCES

APHA. 1998. Method . 8711 Daphnia in Standard Methods for the Examination of Water and Wastewater, 20th Edition. L. S Clesceri, A. E. Greenberg and A. D. Eaton editorial board, M. A. H. Franson, ed., American Public Health Association, Washington, D.C., pp 8-22 to 8-86.

APHA. 1998. Method . 8810. Echinoderm Fertilization and Development (Proposed) in Standard Methods for the Examination of Water and Wastewater, 20th Edition. L. S Clesceri, A. E. Greenberg and A. D. Eaton editorial board, M. A. H. Franson, ed., American Public Health Association, Washington, D.C., pp 8-114 to 8-122..

Clean Washington Center (CWC). 1994. King County Glassphalt Demonstration Project. CWC Technology Brief. http://www.cwc.org/briefs/glass.htm

Clean Washington Center (CWC). 1998. Testing and Certification of Industrial Abrasives Manufactured from Recycled Glass. CWC Technology Brief. http://www.cwc.org/briefs/glass.htm

NIOSH. 1998. Evaluation of Substitute Materials for Silica Sand in Abrasive Blasting; Phase 1. Department of Health and Human Services, Centers of Disease Control and Prevention, National Institute for Occupational Safety and Health, September. Prepared by KTA-Tator, Inc.

U.S. Environmental Protection Agency. 1992. Markets for Recovered Glass. Office of Solid Waste and Emergency Response. EPA/530-SW90-071.

U.S. Environmental Protection Agency. 1994. Recycling and Reuse of Materials Found on Superfund Sites Handbook. Center for Environmental Research Information. Office of Research and Development. EPA/625/R-94/004. September.

U.S. Environmental Protection Agency. 1996. Soil Screening Guidance: Technical Background Document. Office of Solid Waste and Emergency Response. EPA/540/R-95/128. May.

U.S. Environmental Protection Agency. 1997. Emission Factor Document for AP-42 Section 13.2.6 Abrasive Blasting. Final Report. Office of Air Quality Planning and Standards. Emissions Factor and Inventory Group. EPA Contract 68-D2-0159. September.

Washington State Department of Ecology. 1992. Letter by Vern Meinz to Laura Russell. Hazardous Waste Regulatory Section.

Washington State Department of Ecology. 1996. Resource Conservation Recovery Act Model Toxic Control Act. Cleanup Regulations. Chapter 173-340-740 WAC. Publication No. 94-06. Amended 1996

Washington State Department of Ecology. 1997. Biological Testing Methods 80-12 for the Designation of Dangerous Waste. Hazardous Waste and Toxics Reduction Program. Publication No. 80-12. Revised April 1997.

Washington State Department of Ecology. 1998. Dangerous Waste Regulations. Chapter 173-303 WAC. Publication No. 92-91. Amended 1998.

 


APPENDIX A

Table A.1 Summary Statistics for Spent Abrasives TCLP Analytical Results
(units = mg/L)

 

 

As

Ba

Cd

Cr

Cu

Pb

Hg

Se

Ag

Zn

Glass

Mean

<0.114

0.3254

0.015

0.024

1.471

0.295

<0.057

0.168

0.00458

2.787

 

Min- Max Detected

ND
0.06 - 0.706
ND - 0.06
ND - 0.063
0.054 -3.66
ND - 1.01
ND
ND - 0.342
ND
ND - 7.67
 

No. of Samples

5
5
5
5
4
4
5
5
5
4
Copper Slag

Mean

0.09
1.77
0.02
0.05
na
0.546
0.0158
0.055
<0.1
na
 

Min- Max Detected

ND - 0.09
0.3 - 4.1
ND - 0.02
ND - 0.12
na
0.1 - 1.65
ND - 0.06
ND - .12
ND
na
 

No. of Samples

4
4
4
4
0
5
4
4
4
0
Sand

Mean

0.042
1.052
0.395
0.323
na
1.665
<0.03
0.05
0.0063
na
 

Min- Max Detected

ND - 0.1
0.12 - 1.6
ND - 1.1
ND - 0.84
na
ND - 5.7
ND
ND - 0.05
ND - 0.026
na
 

No. of Samples

5
5
5
6
na
6
5
5
5
0

* Mean sample concentration for datasets with only one sample represents the analytical results for the one sample.

Mean sample concentration for datasets with only nondetects represents the highest method detection limit.

Mean sample concentration for datasets with nondetects were calculated using 1/2 the method detection limit.

Mean sample concentrations with smaller maximum values were replaced with maximum values.

**Minimum -Maximum detections were not calculated for datasets with only one sample.

Minimum -Maximum detections for datasets with all nondetects were equal to ND (i.e., nondetect).

Element Key
As Arsenic Pb Lead
Ba Barium Hg Mercury
Cd Cadmium Se Selenium
Cr Chromium Au Silver
Cu Copper Zn Zinc


APPENDIX B

appendixb.gif

 

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