Research Findings – Data Collection on Toxicity of Dust Palliatives Used in Alaska – US EPA (TPD1610087)

U.S. Environmental Protection Agency Office of Research and Development

Washington, DC 20460

Table of Contents

1.0       Introduction…………………………………………………………………………………………………………. 1

2.0              Background………………………………………………………………………………………………………….. 2

2.1        Overview of Issues……………………………………………………………………………………….. 2

2.2        Research Goals…………………………………………………………………………………………….. 2

2.3        Project Objectives…………………………………………………………………………………………. 3

2.4        Research Questions………………………………………………………………………………………. 3

3.0              Data Collection Approach……………………………………………………………………………………… 3

3.1        Reaching Out to Contacts Identified by EPA……………………………………………………. 3

3.2        Primary Documentation Search………………………………………………………………………. 5

4.0              Findings………………………………………………………………………………………………………………. 9

4.1        Palliatives Used in Alaska……………………………………………………………………………… 9

4.2        Characteristics of Palliatives Used in Alaska………………………………………………….. 14

4.3        Toxicity of Identified Palliatives…………………………………………………………………… 17

4.4        Palliative Regulations Applicable to State-Used Palliatives……………………………… 21

5.0       Data Gaps/Research Needs…………………………………………………………………………………… 24

6.0       References…………………………………………………………………………………………………………. 26

List of Figures

Figure 1…… Process to Collect Information on Palliatives Used in Alaska…………………………….. 8

List of Tables

Table 1.        Subject Matter Experts and Affiliations…………………………………………………………… 4

Table 2.        Steps for Primary Documentation Search Using Online Data Sources…………………. 7

Table 3.        Palliatives Used in Alaska: Categories, Products, Manufacturers, and

Chemical Compounds…………………………………………………………………………………. 10

Table 4.        Available Information on Chemical Characteristics of Palliatives Used

in Alaska……………………………………………………………………………………………………. 14

Acronyms and Abbreviations

1.0   Introduction

EPA requested assistance in the investigation of dust palliatives (suppressants) used on road surfaces in the state of Alaska, the fate and transport of these palliatives in the environment, the documented effects to human health and the environment, and the applicable regulations associated with palliative use in Alaska. Aspects of the project, activities performed during the literature search, summarized findings from the effort, and identified data gaps/research needs are all included in this document. This information is organized into five main sections: “Background,” “Literature Review Approach,” “Findings,” “Data Gaps/Research Needs,” and “References.”

2.0           Background

Dust palliatives are products used worldwide to suppress the release of fugitive dust resulting from vehicles traveling on unpaved road surfaces (e.g., dirt roads, gravel roads, unpaved runways). Much of the fugitive dust in Alaska comprises particulate matter that is less than 10 microns in size (PM10), which can lead to adverse health effects in some exposed individuals (Withycombe and Dulla, 2006). Fugitive dust has other potential negative impacts, such as impairing driver safety by reducing visibility and requiring costly and frequent road and runway maintenance (UAF/AUTC, 2013).

Unpaved road surfaces are commonplace in major portions of Alaska, where more than 50 percent of state-owned roads and the majority of local and private roads are unpaved (UAF/AUTC, 2013). For several decades, tribal, state, urban, and rural city governments in the state have been applying palliatives to control and suppress dust on these types of road surfaces. Palliative use dates back to the 1960s with the application of salt-based palliatives, such as calcium chloride and magnesium chloride (Connor, 2015b). Chemical-based palliatives, such as synthetic fluids, have become increasingly popular in Alaska since the early 2000s (Hickman, 2015a; Milne, 2015b). Also, water has been and continues to be a popular method of dust control in Alaska, particularly on construction sites (Barnes and Connor, 2014).

The U.S. market has more than 190 proprietary chemical dust suppressant products, and many other nonproprietary products (e.g., calcium chloride) are available as well (Jones, 2015). Different entities and resources categorize individual palliatives in varying ways, but this report uses the following categories based on project research and subject matter expert input about palliatives applied in Alaska:

• Water
• Salt-based
• Petroleum-based
• Organic Nonpetroleum-based
• Enzymes
• Polymers
• Synthetic Fluids
• Electrochemical
• Clay Additives

2.1            Overview of Issues

The use of palliatives in the state of Alaska has raised various concerns, including the potential impacts on traditional subsistence resources, possible effects on the environment, and unknown human health risks from exposure.

Several rural communities have expressed concerns about palliatives through an Alaska Department of Environmental Conservation (ADEC) survey about dust in 2010. ADEC found that many communities were willing to try chemical dust palliatives, but they wanted more information on the potential toxicity, effects on human health, and effects on the environment, such as the extent of contamination (ADEC, 2010a).

This research effort sought to find information to address the stated concerns of Alaskan tribes and communities. While manufacturers and independent agencies have conducted some testing of products, information from subject matter experts and the literature indicates limited documented knowledge and research on the environmental impacts and health effects of dust palliative use in Alaska. Studies on palliatives have been conducted in locations outside of Alaska, but findings cannot necessarily be extrapolated to Alaska’s unique environment given the variation in results that may come with different study parameters and location conditions. This report does provide information on studies conducted elsewhere to provide perspective (e.g., plant toxicity studies in Colorado and Texas), but it is important to note that only field tests in Alaska can provide accurate predictions of dust palliative performance and impacts in the state.

2.2            Research Goals

This project was created in direct response to questions received from a number of Alaskan tribes and communities about the safety of dust suppressant products. The overarching goal is to evaluate existing knowledge and data gaps on the potential toxicity of palliatives used in Alaska as they relate to possible exposures among the Alaska Native population. Evidence compiled for this project is intended to assist EPA in determining whether palliatives used in the state are safe for use in Alaskan villages, particularly in the context of impacts on subsistence resources and the potential risk to Alaska Natives. To achieve this overarching project goal, the data compilation process focused on addressing the individual objectives stated in Section 2.3.

2.3            Project Objectives

The defined objectives of this project include the following:

• Identifying the specific types of palliatives used in Alaska.
• Exploring the environmental fate and transport of the chemical constituents of each palliative.
• Researching the potential human and environmental toxicity of these palliatives, with a focus on the potential unique impacts to Alaska Native villages.
• Analyzing federal, state, and/or other regulations associated with palliative use in Alaska.

2.4            Research Questions

• How safe are palliatives for humans?
• What are the potential health risks from exposure to palliatives?
• Are existing regulations and advisories adequate to protect Alaska Native communities from harmful exposures?
• Are existing regulations and advisories adequate to protect the environment?

3.0           Data Collection Approach

A data collection effort to gather information about palliatives used in Alaska for dust suppression on roadways was performed. Data collection involved two overarching steps: 1) calling key subject matter experts identified by EPA to gather information by asking a list of pre- approved, project-specific questions (listed below); and 2) searching for and compiling relevant publicly available resources (e.g., published literature) pertaining to palliatives of interest. All information and citations provided by EPA’s recommended experts (and additional contacts identified throughout the process), as well as citations located from searching online resources, in an Excel spreadsheet—referred to as the “bibliographic database” were documented. (Note: the bibliographic database is a Microsoft Excel^® file containing citation information for each reference; it is being provided as a separate deliverable.)

The following subsections describe specific information-gathering activities. Figure 1 at the end of this section highlights each step in the process.

3.1            Reaching Out to Contacts Identified by EPA

The first step in the process involved contacting the initial list of subject matter experts provided by EPA, as well as additional contacts identified by these experts. EPA’s project manager provided ERG with a list of nine contacts with various backgrounds and expertise associated with palliatives used in Alaska, particularly in Alaska Native villages (Table 1). The vision was that these experts could provide information on the specific palliatives used in Alaska and the time periods when they were used. Once obtained, this information was used to identify the chemical makeup of each palliative and other relevant properties needed to address the specific objectives of the literature review effort.

Table 1. Subject Matter Experts and Affiliations

The following list of 10 questions were posed to each contact:

1. Do you know when palliatives started being used in Alaska?

1. Do you have, or know where I could find, a list of palliatives (and their chemical makeup) currently used in the state and those used in the past?

1. Can you point to any existing regulations related to applying palliatives in Alaska? If not, do you know a good resource that might have this information?

1. Are you aware of any studies or other data that evaluate potential health risks of palliative exposure to tribal communities or others (via ingestion, inhalation, or dermal contact)?
2. Are you aware of environmental sampling data related to palliative application in Alaska or elsewhere? For instance, testing to see the chemical concentrations in subsistence resources, such as roadside berries, or in the ambient air in areas where palliatives have been applied?

1. Are there any palliatives you or your organization/company consider to be safe, or that you recommend for use in road or runway applications?

1. Are there data gaps you are aware of, which you think need investigation now or in the future?

1. Can you point to any resources or published papers that we should consider?

1. Is there anyone else you recommend we contact on this topic?

1. As our research progresses, would it be okay for ERG to contact you again if other questions arise?

3.2            Primary Documentation Search

Palliative-specific information was gathered from various online sources. This process involved searching publicly available databases and websites using a developed assemblage of relevant keywords and various keyword search strings. We used the following search tools:

• Google Scholar (https://scholar.google.com/).
• RefSeek (http://www.refseek.com/).
• Scientific search engines PubMed (http://www.ncbi.nlm.nih.gov/pubmed) and the

U.S. National Library of Medicine’s Hazardous Substances Data Bank (HSDB;http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB).

• State reference sources: Alaska Department of Environmental Conservation (http://dec.alaska.gov/), University of Alaska Fairbanks/Alaska University Transportation Center (http://ine.uaf.edu/autc/), and Alaska Department of Transportation and Public Facilities (http://www.dot.state.ak.us/).

• Palliative-specific safety data sheets (SDSs), searching chemical manufacturing websites and Google using product names.

The strategy for identifying relevant keywords and keyword search strings focused on the use of general terms, palliative types, chemical names, and additional specific project-related words. The process for each of these is summarized below.

• General search termscomprised some combination of the words listed below.
  • Who and where: Alaska, Alaska tribes, Alaska Native villages.
  • What: dust palliative, dust suppressant, dust control, dust abatement.
  • Details: fate and transport, toxicity, environmental effect, environmental impact, human health, subsistence, regulation.

• Palliative type search termsconsisted of some assemblage of the words listed below.
  • Palliative type: salt, petroleum, organic nonpetroleum, electrochemical, polymer, synthetic fluid, enzyme, clay additive.

• What: dust palliative, dust suppressant.
• Details: fate and transport, toxicity, environmental effect, environmental impact, human health.

• Chemical search terms comprised information specific to each chemical associated with particular palliative(s). The purpose of searching for specific chemicals was to identify the particular “Details” associated with each one, as identified below.

• Chemicals: Chemical name* + dust palliative, Chemical Abstracts Service Number (CASRN)* + dust palliative, calcium chloride + dust palliative, magnesium chloride + dust palliative.

• Details: fate and transport, toxicity, environmental effect, human health.

*Chemical compositions of dust palliative products and ingredient CASRNs are taken from SDSs whenever available. A full list of identified products and their associated chemical compositions, when available (i.e., are not proprietary ingredients), are listed in Section 3 of this document. Chemicals that account for only a small percentage (<5 percent) of a product were not included in searches.

• Additional specific project-related keyword strings were searched in online websites and databases. These included:

• Alaska + control combined with one of the following: fugitive dust, rural dust, dust emission, unpaved road, road dust, PM10 (e.g., Alaska + control + fugitive dust).

• Alaska + manage combined with one of the following: rural dust, dust emission, unpaved road, road dust, PM10 (e.g., Alaska + manage + dust emission).

• Dust palliative, dust suppressant, dust suppression, road dust management, dust abatement, and dust control product were each combined with one of the following: Alaska, subsistence, regulation, environment, health, toxicity, fate and transport (e.g., dust palliative + Alaska, dust suppression + regulation).

When searching for reference literature, the process involved reviewing abstracts, identifying references most likely to contain relevant information, and obtaining full-text references when possible. Throughout the literature search process, relevant information about each reference was compiled in the Excel-based bibliographic database (e.g., author, date, title, URL [if applicable], full citation, and summary notes for the reference).

While some reference materials were available online in their entirety, others were limited to abstracts or brief summaries. To complete the primary literature search, a tiered approach was used for reviewing and compiling relevant information. The process included searching online databases for references potentially relevant to palliatives and project objectives (Step 1), targeting documents that could be useful based on a review of abstracts and other information (Step 2), and obtaining and reviewing full references for those deemed relevant (Step 3). Each step is summarized in Table 2.

Table 2. Steps for Primary Documentation Search Using Online Data Sources

Figure 1. Process to Collect Information on Palliatives Used in Alaska

4.0           Findings

This section synthesizes the findings of the interviews and literature review, which are summarized in the following subsections: “Palliatives Used in Alaska” (Section 4.1), “Characteristics of These Palliatives” (Section 4.2), “Toxicity of These Palliatives” (Section 4.3), and “Regulations Applicable to Palliative Use in Alaska” (Section 4.4).

Hundreds of search queries and all identified literature were tracked in the bibliographic database. A total of 247 resources were identified, with 125 marked as relevant to the project scope and requiring a full review. Articles deemed relevant were those that provided information directly related to the project objectives, goals, and research questions (e.g., dealt with palliative toxicity, documented application of palliatives in Alaska). Articles were deemed irrelevant if they fell outside of this scope (e.g., referred to palliative performance, summarized information on dust effects). Notably, some of the retained resources pertain to research conducted outside of Alaska, but were flagged because they may be relevant to some of the project’s research goals (e.g., results of products tested in other states). Most of the palliative-specific information cited in this report came from product SDSs, which are also tracked in the bibliographic database and referenced in Section 6 of this report.

4.1            Palliatives Used in Alaska

This section discusses the palliatives identified as having been used in Alaska, locations in the state where application is generally known to occur, and typical application methods.

Table 3 lists the categories and the corresponding products, manufacturers, and chemical compositions for palliatives reported to have been applied in Alaska based on subject matter input and literature. Though all of these palliative categories have been applied in Alaska, some are more widely used than others. According to Barnes and Connor (2014), the most appealing types of palliatives for use in the state are water, salt-based palliatives, synthetic fluids, and polymers because of their product availability, cost, and effectiveness. In addition, non-salt-based chemical palliatives have gained popularity for several reasons, such as their effectiveness at reducing dust and their relative price efficiency (Milne, 2015c).

Other palliatives—vegetable oil, tall oil, Soil  Sement®,  Soiltac®,  Perma-zyme,  and  Top Seal®—have had a very limited number of applications in the  state,  with  testing  sometimes representing the only application. Similarly, acrylic-based products and other polymers are reportedly not generally used much in Alaska.  Clay  additives  are  infrequently used due to their high cost; montmorillonite was used in Fort Yukon, but other areas of application are not well documented in Alaska (Milne, 2015a). Likewise, though one electrochemical product was tested in the state, it performed poorly and was not used again (Connor, 2015a).

Table 3. Palliatives Used in Alaska: Categories, Products, Manufacturers, and Chemical Compositions

1 Information on chemical compositions is taken from SDSs for all products except for Denali Dust Control Concentrate. As cited, information for Denali Dust Concentrate was taken from an informational sheet provided by the manufacturer.

2 This product was discontinued.

3 Enzymes may be categorized under electrochemical products by some entities but are considered as their own category in this report.

4 The synthetic fluids category has been debated among product manufacturers. While many products market themselves as “synthetic,” the synthetic fluids category should be reserved for products that are fluids derived through chemical transformation. This definition separates this fluid from the category of petroleum-based organic fluids produced by physical separation (fractionation, distillation) in the refining process. Fluids that have gone through physical separation along with a minor chemical reaction such as cracking and hydroprocessing, as would be the case with mineral oils, are also excluded from the class of fluids considered synthetic (U.S. EPA, 1996; Federal Register, 2001). Midwest Industrial Supply, the manufacturer of synthetic fluids EK35® and EnviroKleen®, invented the patented product category Synthetic Organic Dust Control (Midwest Industrial Supply, Inc., 2014). This report follows the new definition of synthetic fluids agreed upon by Midwest Industrial Supply and Soilworks, two major manufacturers of synthetic fluid dust palliatives. EK35®, EnviroKleen®, and Durasoil® fall under this definition.

Interviews and the literature pointed to other types of palliatives, but we were unable to identify sufficient documentation to research them further. These include:

• Soybean oil soapstock
• Beet juice
• Electrochemical products
• A vegetable oil-based product called Denali Dust Control Concentrate.

We obtained information on locations of palliative application regarding Alaska DOT&PF’s use of palliatives in the state, but data are lacking on locations where application may occur by other entities. Specifically, Alaska DOT&PF uses dust palliatives for various state projects, including those dealing with city roads, highways, and airports. According to subject matter experts and published documentation, calcium chloride has been the main type of product used on roads managed by Alaska DOT&PF; Alaska DOT&PF records show that calcium chloride was applied to more than 800 miles of roads and highways each year from 2005 to 2010 (ADEC, 2010b; EcoPlan Associates, Inc., 2007).

Based on research conducted for this project, it appears that Alaska DOT&PF has applied palliatives at more than 50 airports since 2001 (Milne, 2015b). Documentation indicates the following have been used for airport projects: EK35®, EnviroKleen®, Perma-Zyme, Lignosite® 458 Sodium Lignosulfonate, and Durasoil® (ADEC, 2010b; EcoPlan Associates, Inc., 2007).

Though the documentation is limited on other entities using palliatives in the state and locations where application might occur, there has been at least one project that involved testing palliatives on village roads. In 2009, the Alaska legislature awarded the DOT&PF $650,000 to run palliative trials in what was referred to as the “8 Villages” project. For this project, the DOT&PF picked eight Alaska Native villages with known dust problems (Ambler, Buckland, Kiana, Kotzebue, Noorvik, Noatak, Bethel, and St. Mary’s), applied palliatives to the unpaved roads there, and monitored the efficacy and longevity of the palliatives. However, the villages were inconsistent in their application methods, and the DOT&PF was unable to determine which palliatives performed best (Milne, 2015c). Another study by Eckhoff (2012) looked at palliatives applied by Alaska DOT&PF to other parts of the state, involving gravel roads in Eagle and North Pole and a gravel runway in Tetlin. The conclusion from the results of the tests conducted in Eagle were that the dust palliative application provided a reduction in PM10 emissions compared to the untreated control section over a two year time period. The results of tests conducted in North Pole determined that the dust palliative’s effectiveness began to decrease within two months of the initial application and its longevity was less than one year. Testing in Tetlin was inconclusive, additional testing is required before the effectiveness and longevity of the dust palliative can be evaluated.

Based on public Alaska DOT&PF records, the following palliatives were applied to village roads at least once during the 2005 to 2010 time period: EnviroKleen®, Earth Armour™, Soil- Sement®, LSP-400, Alastac, and AlastaSeal (ADEC, 2010b). During the same time period, the following were applied on other non-village roads (i.e., roads not specified as village roads in the source  document)  at  least  once:  EK35®,  EnviroKleen®,  Durasoil®,   Soiltac®,   Top   Seal®, Dustaway, and the now discontinued Freedom Binder 400 (ADEC, 2010b). Note: Other products have been used in Alaska since 2010, such as the application of EK35® and Durasoil® at airports, but documentation of these uses is not readily available to the public (Milne, 2015b).

Application of palliatives can vary by the specific product used, but they are typically applied either topically or mixed into the top layer of the soil (Piechota et al., 2004). If applied topically, palliatives are generally applied as liquids using sprayer equipment attached to the back of a vehicle. Salt-based and polymer palliatives may also be applied in solid form as flakes that are spread and then mixed into the soil. Petroleum-based asphalt emulsions, such as PennzSuppress® D, are often heated first to ensure smooth application. Product information will specify mixing requirements, application rates, and proper storage. Many liquid palliative products are diluted with water to create the correct concentration for application (Piechota et al., 2004).

4.2            Characteristics of Palliatives Used in Alaska

This section discusses chemical properties of the various identified palliative types, including how long the chemicals may stay in the environment after product application and how they move through environmental media (e.g., air, soil). Rettinger (2015) indicated that the available environmental sampling data for state-used palliatives are typically only documented by manufacturers in their product SDSs. While most of the SDSs obtained for palliatives used in Alaska do include some information about environmental fate and transport, the level of detail was limited in most cases. The relevant information that could be located for each palliative category is highlighted in Table 4.

The fate and transport of salt-based products are perhaps the best understood among these palliative categories. For many products, the extent of what is known may be limited to whether the substance is soluble in water. Moreover, though potential bioaccumulation was documented for a few products, little information was found on the environmental fate and transport of palliatives used in Alaska.

Table 4. Available Information on Chemical Characteristics of Palliatives Used in Alaska

1 This product was discontinued.

4.3            Toxicity of Identified Palliatives

This section summarizes the toxicity information that was found for the palliatives used in Alaska by category. It also discusses documented human health effects associated with product use, potential environmental impacts from palliatives, and some very limited findings associated with dust palliative application and adverse effects on subsistence food sources. Information below is presented for each overall palliative category, and for the specific palliatives within that category when information is available. Most of the toxicity information about palliative products in this section comes from manufacturer SDSs. Where possible, ERG cited relevant toxicity and health effects data from the peer-reviewed scientific literature was cited, but reference to the SDSs was necessary in most cases because that was the only information available.

Generally, we identified limited research or documentation describing the toxicity and potential health impacts of dust palliatives, particularly related to resultant exposures to the general public. Existing studies have been carried out in a variety of environments and geographical

settings, therefore, findings cannot necessarily be extrapolated to apply to Alaska’s environment, where factors such as soil type and climate may vary from those present in a palliative study conducted elsewhere (Kunz, 2015).

Water

• Water is non-toxic, and its use as a palliative does not have any negative health or environmental implications.

Salt-Based

• No major human health concerns are associated with handling salt-based palliative products. Irritation may occur in the event of skin or eye contact (Barnes and Connor, 2014).

• As with salt water, there are potential impacts to freshwater fish and plants due to the accumulation, potential leaching, and runoff of chloride (ADEC, 2008).

• Health/environmental impact data identified for magnesium chloride are highlighted below (note: none of these studies were conducted in Alaska):

• A study of magnesium chloride’s effects on roadside vegetation found a higher prevalence of plant damage in areas where magnesium chloride applications were relatively high and where plants were located downslope from roads and could receive runoff (Goodrich et al., 2008).

• High concentrations of magnesium chloride ions in the soil may be toxic or inhibit regular plant water and nutrient uptake. If a plant takes up chloride through its roots, the chloride can accumulate, killing leaves and possibly the plant itself (Goodrich and Jacobi, 2008, 2012).
• One study detected no environmental effects following the application of a magnesium product during a 12-month monitoring period (Kunz and Little, 2015). However, this study did not address the potential longer term effects or effects associated with residual buildup of product from repeated applications.

• Another study observed that magnesium chloride moved into roadside streams, but the concentrations detected were below the levels determined to harm aquatic organisms (Goodrich et al., 2009).

Petroleum-Based

• Some petroleum-based products may be carcinogenic. They contain semi-volatile PAHs and VOCs, some of which are known human carcinogens (ADEC, 2008).

• No ingredients in Earth Armour™ are classified as carcinogenic. Fumes from the product may be irritating to breathing passages upon excessive heating, but inhalation is highly unlikely. Repeated inhalation of fumes or mists may cause irritation to the respiratory tract, and buildup

of product deposits in the lungs may lead to fibrosis and reduced pulmonary function (Midwest Industrial Supply, Inc., 2010).

• Asphalt emulsions, such as PennzSuppress®D, are often heated to allow for smooth application. The heated emulsion releases PAH- and VOC-containing vapors that can be inhaled or absorbed through the skin of the people applying the product (ADEC, 2008). PennzSuppress® D may cause irritation in the respiratory tract if fumes generated from heating are inhaled, but there are no data to indicate that the product is carcinogenic (American Refining Group, Inc., 2012).

Organic Nonpetroleum-Based

• Toxicological studies have shown that lignosulfonates are non-toxic, and are generally recognized as safe under 21 CFR 582.99 (Apun, LLC, 2009).

• There is a low order of toxicity towards fish and plants, but no human health problems are expected (Apun, LLC, 2009).

• Testing for Lignosite® 458 Sodium Lignosulfonate showed no mortality or observable signs of toxicity in rats after four hours of inhalation exposure (Georgia-Pacific West, Inc., 2000).

• Tall oils have a high biological oxygen demand when they break down so these types of products may deplete dissolved oxygen in water if leaching or spilling occurs. The resulting lack of oxygen may in turn lead to fish kills (ADEC, 2008).
• The product AlastaSeal may cause irritation to the respiratory tract if fumes or mists are inhaled. If inhaled, product deposits may build up in the lungs, leading to fibrosis and reduced pulmonary function (Apun, LLC, 2015).

• When applied properly, AlastaSeal is not known to pose any ecological problems (Apun, LLC, 2015).

• While marketed as safe and non-toxic, Denali Dust Control Concentrate has little documentation to support these claims (Denali Materials, Inc., 2015). In general, there appears to be a lack of literature on the environmental impacts and potential toxicity of vegetable oil- based palliatives.

• Very little is known about the toxicity of soybean oil soapstock or beet juice as palliatives. As noted, these products are used infrequently, if at all, in Alaska (Hickman, 2015a).

Enzymes

• Perma-Zyme is a proprietary blend of enzymes produced from food products and contains no hazardous constituents (Pacific Enzymes, Inc., 2015). Specific information regarding toxicity is unavailable.
• Top Seal® is non-biodegradable and non-hazardous based on Resource Conservation and Recovery Act regulations. Ecotoxicity testing of similar materials indicates compliance with most standards for aquatic life (Soils Control International, Inc., 2006).

Polymers

• Soil-Sement® has been tested by various independent agencies, and testing results show that, when applied properly, it will not negatively impact soil or water quality in terms of toxicity (Midwest Industrial Supply, Inc., 2013, 2015c). Fish toxicity studies have demonstrated the product meets requirements, and animal studies were not carried out due to this absence of aquatic toxicity. Other environmental data indicated the presence of seven metals and one VOC in Soil-Sement®, but all were detected at levels lower than EPA’s soil risk based concentrations (Midwest Industrial Supply, Inc., 2015c).

• Human exposure  to  Soiltac®  is  considered  unlikely,  and  human  toxicity  information  is unavailable. When  applied  properly,  Soiltac®  is  not  expected  to  pose  any ecotoxicity or ecological problems (Soilworks, 2015b, 2015c).

• Vinyl acetate and acrylic polymer based palliatives, such as Soiltac® and Soil-Sement®, are stable in soils after curing; they are; thus, unlikely to be available to terrestrial organisms or be transported in runoff water. However, there are lingering concerns regarding the degradation of polymer products and the potential for inhalation exposures, which have not been studied extensively, if at all (Steevens et al., 2007).

• No information on toxicity and chemical fate of LSP-400 was found.
• DirtGlue® is relatively non-toxic, including to aquatic life (GeoCHEM, Inc., 2010).

Synthetic Fluids

• Testing shows that EK35®, when applied properly, will not negatively impact soil quality or pose any ecological problems. EK35® was tested independently through EPA’s Environmental Technology Verification program, and aquatic toxicity testing shows a range of toxicity from non-toxic to moderately toxic depending on the species and the exposure time (MRI and RTI, 2006). In a study of hydrologic impacts, EK35® had a higher concentration of contaminants than polymer products such as Soil-Sement® (Piechota et al., 2002). Inhalation is unlikely, but repeated inhalation of fumes or mists may cause irritation to the respiratory tract. Product deposits may also build up in the lungs and lead to fibrosis and reduced pulmonary function. EK35® is not known to be carcinogenic or pose a reproductive risk to humans (Midwest Industrial Supply, Inc., 2015a). EK35® does not contain PAHs (Nabess, 2014).

• EnviroKleen® was tested independently through EPA’s Environmental Technology Verification Program. Comparison of EPA guidelines to the LC50s of all species tested shows that EnviroKleen® is practically non-toxic to all species (RTI and MRI, 2005). Inhalation is unlikely, but repeated inhalation of fumes or mists may cause irritation to the respiratory tract. If inhaled, product deposits may build up in the lungs and lead to fibrosis and reduced

pulmonary function. EnviroKleen® is not known to be carcinogenic or pose a reproductive risk to humans (Midwest Industrial Supply, Inc., 2015b).

• Durasoil® is not classified as a carcinogen, and does not pose a reproductive risk to humans. According to Durasoil®’s SDS, it is practically non-toxic to all species based on EPA guidelines, and there are no known significant impacts in the environment (Soilworks, 2015a).

Electrochemical

• Use of specific electrochemical products is not documented in Alaska, but the category is included in this report because an electrochemical product was tested once in the state. It performed poorly, however, and was not used again (Connor, 2015a).

• Environmental impacts, chemical fate and transport, and toxicity levels are not well studied.

Clay Additives

• No toxic impact from the use or application of natural clay additives is expected (ADEC, 2008).

No information was found in the literature that specifically documented the effects of palliatives on subsistence food sources. Knowledge that exists is anecdotal or gained through conversations with local residents. Calcium chloride, for example, is sometimes not accepted in villages because it may negatively affect the taste of subsistence berries and fish (Connor, 2015b). Without moisture, chloride salts can break down into dust, become airborne, and then land on berries and fish that have been left outside to dry (Hickman, 2015a). The subject matter experts contacted for this project did not know of similar complaints associated with other types of palliatives.

4.4            Palliative Regulations Applicable to State-Used Palliatives

Information obtained from subject matter experts and the literature review identified few federal or state regulations that directly apply to palliative toxicity and use in Alaska, but there are some general guidelines that outline what can and cannot be used.

At the federal level, there is one regulation and one law, respectively, that apply: 1) waste oil (i.e., oil derived from crude oil or synthetic oil that has been contaminated through use) is prohibited for use as dust control (federal regulation 40 CFR Part 279, Standards for the Management of Used Oil, Subpart I), and 2) a dust palliative cannot contain hazardous materials, which are defined as chemical substances that present “an imminent and unreasonable risk of serious or widespread injury to health or the environment” (Federal Toxic Substances Control Act [15 U.S.C.§ 2606]) (Kunz, 2015).

State regulations pertaining to clean air, clean water, and management of hazardous waste and materials can apply to dust control (Benedict, 2003). In Alaska, state regulation 18 AAC 75 pertains to oil and other hazardous substances and prohibits the use of oil as a dust suppressant if the oil contains any of the following (ADEC, 2015a):

• Polychlorinated biphenyls (PCBs) in any detectable concentration
• Total volatile aromatics in 5000 parts per million by weight or greater
• Total halogenated volatile organics in 100 parts per million by weight
• Lead in 300 parts per million by weight or greater

Alaska DOT&PF has regulations for palliative use on state-funded construction projects. Item P-167 in the agency’s standard specifications outlines requirements for runway stabilization and dust palliative use. These specifications state that in order for a product to be used, the manufacturer must certify the product is environmentally safe for aquatic species and requires no specialized response or cleanup if a spill occurs (ADOT&PF, 2015a). The Central and Northern Alaska DOT&PF Regions have regional specifications that follow the general P-167 outline. Environmental testing requirements for the Northern Region include bulk analysis, toxic characteristic leaching procedures, and testing for aquatic toxicity with three or more of these species: Cladoceran (Ceriodaphnia dubia), fathead minnow (Pimephales promelas), mysid shrimp, and 7-day rainbow trout (Oncorhynchus mykiss) (ADOT&PF, 2015b). All Alaska state- funded projects must have specifications similar to the P-167 or applicable regional template. While no governing body officially regulates how specifications are written, DOT&PF may review them (Hickman, 2015b).

Although they are not laws or regulations, American Society for Testing and Materials (ASTM) and American Association of State Highway and Transportation Officials (AASHTO) specification standards are applied in Alaska for road use for two palliatives: calcium chloride and asphalt emulsion (Jones, 2015).

No guidelines and specifications were available specific to other palliative products used in the state, and as Jones (2015) points out, there are no official guidelines that specify how agencies and entities maintaining roads should obtain and apply palliative treatments. There are some guidance documents to help practitioners select dust palliatives best suited to their particular site conditions, such as the U.S. Forest Service’s Dust Palliative Selection and Application Guide (Bolander and Yamada, 1999). The Federal Highway Administration is currently sponsoring the preparation of a new guideline with specifications for obtaining and selecting chemical palliative treatments for unpaved roads, but it has yet to be finalized (Jones, 2015).

As evidenced herein, very limited regulations specific to palliative use, application, and toxicity exist in Alaska at this time. For the regulations and guidance that are in place, no documentation was found to indicate whether they are adequate to protect human health and subsistence resources in Alaska.

5.0   Data Gaps/Research Needs

The previous sections of this document summarize the relevant information identified for palliatives used in Alaska. The data collection effort revealed several remaining information gaps and research needs. The bullets below highlight those gaps identified in available documentation and by the experts we contacted. These are organized to generally align with the following categories used in Section 4, “Findings: Palliatives Used in Alaska” (Section 4.1), “Characteristics of Palliatives Used in Alaska” (Section 4.2), “Toxicity of Identified Palliatives” (Section 4.3), and “Regulations Applicable to State-Used Palliatives” (Section 4.4).

Palliatives Used in Alaska

• Alaska DOT&PF provided information regarding the locations in which they know palliatives have been applied in Alaska. However, no central database or other information source was identified to pinpoint all the locations and Alaska Native villages where palliatives are obtained and applied.

Characteristics of Palliatives Used in Alaska

• There is a lack of reliable information on the environmental fate and transport of most palliatives.

• The limited available environmental sampling data tend to come from the palliative manufacturers, rather than from third-party testing.

• There have been several studies focused on devising a methodology for testing the environmental impacts of dust palliatives, but no standardized procedures have been established.

• Most environmental sampling data come from measuring raw undiluted product, rather than from field sampling in the open environment where accurate indicators, such as levels of palliative uptake, can be measured.

• Many palliatives lack precise data on their chemical compositions and batch-to-batch consistency.

• Many palliative ingredients are proprietary, which prohibits the ability to search for information related to those particular unspecified chemicals.

• Very little is known about products that have not been used widely in Alaska, such as Perma- Zyme and vegetable oil.
• Research at the University of Alaska Fairbanks has raised some concerns over the fate and transport of vegetable oil because it turns into a powder in the presence of sunlight; research continues to investigate this further.

• No or extremely limited information is available to assess any aspects of certain palliatives applied in Alaska: soybean oil soapstock, beet juice, electrochemical products, and

vegetable-oil based palliatives, such as a new product called Denali Dust Control Concentrate.

Toxicity of Identified Palliatives

• Most toxicity testing is conducted by palliative product manufacturers, with the majority of these tests occurring in lab trials on fish. Only a few types of palliatives have been assessed for their impacts on vegetation. Thus, there are data gaps on the toxicity of many palliatives to other organisms, such as emergent and established plants, soil invertebrates, and terrestrial vertebrates (i.e., reptiles, aquatic organisms other than those tested, and mammals).

• There is a lack of field studies in varying climates, which may be useful for assessing not only the effectiveness of products, but also their impacts on water, air, plants, and animals not already tested in lab trials.

• No data were found on direct human health effects associated with exposure to palliatives applied in the environment.

• The question of palliative effects on human health is relatively unexplored in comparison to the known health risks of exposure to dust itself.

• The health effects associated with inhaling the powder generated when vegetable oil breaks down in the presence of sunlight are largely unknown.

• Knowledge gaps exist for certain categories of palliatives, such as polymers. While inhalation is unlikely for many palliatives at the time of application, there are lingering concerns regarding the degradation of polymer products and the potential for inhalation exposures at a later time.

• The possible effects of palliatives on subsistence food sources are not well understood or documented in the literature. The only knowledge that exists is anecdotal or gained through conversations with local residents; to date, no formal collection of this information has occurred.

Palliative Regulations Applicable to State-Used Palliatives

• There are very limited federal, state, or other regulations that pertain to palliative toxicity and use in Alaska. While there are some rules that generally apply to the use of palliatives, there are no data available to determine whether these are adequate to protect human health and the environment.

Other Gaps/Research Needs

• Gathering feedback from communities in Alaska where palliatives have been applied may provide valuable information about the concerns some communities have expressed and what may help or negatively impact them.

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