CalTrans Risk Asssessment Implementation Plan 1996

Table of Contents

• Chapter 1.0 Introduction

• Chapter 2.0 Risk Assessment Advisory Committee Recommendations

• Chapter 3.0 Caltrans Risk Assessment Practices And Policies

• Chapter 4.0 Caltrans Implementation Plan

Introduction

This report presents a study conducted by the California Department of Transportation (Caltrans) in response to Executive Order W-137-96 requiring the implementation of recommendations made by the Risk Assessment Advisory Committee (Committee) to improve the risk assessment process in all California state agencies, departments, boards and offices. The study included a detailed review of the Committee recommendations, selection of recommendations that apply to Caltrans’ programs, review of the current status of those programs in context with the recommendations and an implementation plan to make any needed improvements to the current Caltrans policies and procedures.

1.1 Legislation

In 1993, the California state legislature directed the Office of Environmental Health Hazard Assessment (OEHHA) within the California Environmental Protection Agency (Cal/EPA) to conduct an external scientific peer review of the risk assessment practices used by Cal/EPA. The Committee, a group of experts outside the California state government, was appointed for this task. The members of the Committee include experts in public health, toxicology, epidemiology, engineering, chemistry, modeling, and statistics. Specifically, the Committee was to examine whether the risk assessment practices of Cal/EPA are based on sound science and, secondly, to assess the appropriateness of any inconsistencies between the practices of Cal/EPA and those of the US Environmental Protection Agency (US EPA) and the National Academy of Sciences.

The Committee completed its comprehensive, external peer review of the risk assessment practices used by Cal/EPA. The Committee’s final report, A Review of the California Environmental Protection Agency’s Risk Assessment Practices, Policies, and Guidelines (October 1996), describes the observations and findings and presents the recommendations of the Committee.

On December 10, 1996, Governor Wilson issued Executive Order W-137-96 which requires all California state agencies, departments, boards and offices that "assess the toxicity of exposure to, or risk of chemicals in the environment to human health" to develop implementation plans, as part of their strategic planning process, that address the recommendations of the Committee.

1.2 Caltrans Risk Assessment Study

Caltrans responded to Executive Order W-137-96 with a review of the Committee’s recommendations and identified the actions described in this report to respond to the Order. Many of these identified actions have already been implemented by Caltrans. The recommendations of the Committee were implemented by Caltrans in a four step process that is presented in this Report:

• Chapter 1 Introduction: In this step, the purpose for conducting this study is described.
• Chapter 2 Risk Assessment Advisory Committee Recommendations: In this chapter, an overview of the Committee’s recommendations is presented and those recommendations by the Committee which are applicable to Caltrans programs are identified. Some recommendations are not applicable to specific departments, such as Caltrans, because they address setting consistent scientific standards that apply to all California state agencies, departments, boards. These recommendations are most appropriate for Cal/EPA to address.
• Step 3 Chapter 3 Caltrans Risk Assessment Practices and Policies: In this step, Caltrans identifies the offices with programs that use risk assessment policies. Two Offices of Caltrans: the Office of Environmental Engineering (OEE) and the Office of Hazardous Waste Management (OHWM) use risk assessment policies and procedures in some of their programs. A review of the programs in these offices was conducted to determine which programs should be included in this study. Next, each of the applicable programs was reviewed to identify current policies and procedures in each of the eight subcategory areas.
• Step 4 Chapter 4 Caltrans Implementation Plan: In this chapter, the implementation plan that will be used as part of the Caltrans strategic planning process to address the recommendations of the Committee is presented.

Chapter 2.0 Risk Assessment Advisory Committee Recommendations

The Committee examined current risk assessment practices and made a series of recommendations to Cal/EPA to improve risk assessment practices and protocols in California state agencies, departments, offices, and boards that use risk assessment. Risk assessment practices and protocols are those which assess the toxicity of exposure to, or risk of chemicals in the environment to human health. This chapter presents an overview of the Committee’s recommendations and the specific recommendations that were identified in this study as applicable to Caltrans.

2.1 Overview of Risk Assessment Advisory Committee Recommendations

The Committee’s recommendations focus on improving the scientific basis of the risk assessment efforts, assuring consistency in practices of data management and quality control, and development of continuous improvement programs. The recommendations also encourage Cal/EPA to take the lead in working with US EPA to harmonize activities in order to use State resources most efficiently and provide consistency in its regulatory activities.

The Committee grouped their recommendations into five categories: cross-cutting issues, hazard identification, dose-response evaluation, exposure assessment, and risk characterization.

Cross-Cutting Issues: These are issues that traverse many aspects of the risk assessment practices, policies, and guidelines of Cal/EPA and include - incorporation of new science into risk assessment, consistency and harmonization, resources and organization, guidelines, and peer review and public input.

Hazard Identification: Evaluates toxicological properties of chemicals to determine whether exposure to that chemical can cause an increase in the incidence of an adverse health condition.

Dose-Response Assessment: Assigns a toxicity factor to each chemical which quantitatively describe the relationship between an exposure (in terms of dose to the individual) and the potential for an adverse effect.

Exposure Assessment: Describes the potential ways that people might come into contact with chemicals present in the environment. Recommendations were made on the two phases of exposure assessment - human intake parameters and fate and transport properties.

Variability, Uncertainty, and Risk Characterization: Discusses the relationship between exposure and toxicity of a chemical and how certain a risk assessor is that the assumptions made accurately describe the ways people can come into contact with chemicals and the potential for adverse health effects.

2.2 Selection of Applicable Recommendations

The Committees’ recommendations apply to all risk assessment practices and policies. Some of these recommendations can not be implemented by Caltrans because they address consistency of practices and policies that apply to all California state agencies, departments, and boards. To determine the applicable recommendations, Caltrans met with Dr. David Ting of OEHHA which has been given the responsibility of overseeing the response to Executive Order W-137-96 and implementing the Committee’s recommendations.

Dr. Ting and Caltrans representatives agreed that the Committee’s recommendations within the categories discussed in Section 2.1 of this report, Hazard Identification and Dose-Response, needed to be addressed uniformly for all California state agencies, departments, offices and boards. Therefore, Caltrans will coordinate with Cal/EPA on those recommendations.

This study reviewed the recommendations in the remaining three categories, Cross-Cutting Issues, Exposure Assessment and Variability, Uncertainty and Risk Characterization, to frame the criteria for evaluating Caltrans current practices and polices and determining an implementation plan. Forty-five narrative recommendations were identified.

The Caltrans review of the recommendations noted general similarities and grouped the applicable recommendations into eight subcategories. The specific recommendations, made by the Committee, that fall into these eight subcategories, are summarized in Attachment A. These subcategories, described below, were used to evaluate the policies and procedures used by Caltrans.

Training: Continuous education is needed to be certain that expert personnel keep abreast of new developments. Continue to look for, and implement ways of involving risk managers and stakeholders in risk assessment, including the development of guidelines, assessments, workshops, and reviews. Mechanisms such as two-way temporary staff exchange programs, forums and training sessions.

Data Management: Institute measures for quality control of data in databases and data being added to the databases. For example, the quality of data relies, in part, on the sampling strategy employed. Additionally, improve the accessibility of data to all interested parties.

Peer Review: Develop a formalized policy for internal and external peer review of program activities and reexamine systems currently in place.

Receptor-Based Exposure Assessments: Additional monitoring of human exposure is needed. Receptor-based exposure assessment means assessing exposure where the receptors are located. Cal/EPA should acknowledge the uncertainty that results from the reliance on scenario based exposure assessments.

Exposure/Fate and Transport Models: More effort is needed to validate fate and transport models with real experimental data. In assessing transport and dispersion models, the quality and characteristics of input data to the models, such as emissions data and dispersion parameters, should be considered in addition to the validity of the models themselves.

Communication/Information Sharing: Efforts towards consistency and harmonization between boards and departments and their federal counterparts have begun, appear to be useful, and should be encouraged.

Decision Making and Risk Management Policies: Policies and procedures for addressing the translation or risk assessment uncertainties into risk management policy should be developed. Continue to look for, and implement, ways of involving risk managers and stakeholders in risk assessment, including the development of guidelines, assessments, workshops, and reviews.

Process Improvement: Seek out and implement ways of simplifying and streamlining the process of risk assessments.

Chapter 3.0 Caltrans Risk Assessment Practices And Policies

In this chapter, Caltrans identifies the offices with programs that use risk assessment protocols as described in the Committee’s recommendations. The Executive Order applies to programs that conduct quantitative risk assessment. Risk assessment practices and protocols are those which assess the toxicity of exposure to, or risk of chemicals in the environment to human health.

Two Offices of Caltrans: the Office of Environmental Engineering and the Office of Hazardous Waste Management use risk assessment policies and procedures in some of their programs. A review of the programs in these offices was conducted to determine which programs should be included in this study. Those programs that estimate health risk or collect data used to protect human health were included in this evaluation. The following three programs were identified:

Quantitative Risk Assessment (Office of Hazardous Waste Management): This program includes preparation of quantitative risk assessments which measure the potential for adverse health effects due to exposure to chemicals in impacted soil and groundwater. The risk assessments are out-sourced and not prepared by Caltrans staff. This program was evaluated in this study although the recommendations of the Committee do not apply to out-sourced risk assessments.

Air Quality Research (Office of Environmental Engineering): This program does not use quantitative risk assessment but does collect air samples to determine receptor-based exposure to chemicals of concern and also conducts fate and transport modeling.

Storm Water Monitoring (Office of Environmental Engineering): This program collects data on concentrations of constituents in storm water but does not use quantitative risk assessment. These data are used to comply with National Pollution Discharge Elimination System (NPDES) permits as well as obtain information relevant to implementation of the storm water management program. NPDES permit limits are designed to protect human and ecological receptors.

3.1 Quantitative Risk Assessment (Office of Hazardous Waste Management)

The Office of Hazardous Waste Management uses risk assessment in a variety of projects to assess the potential impact to human health and/or the environment by chemicals in the soil and groundwater at sites where projects will be constructed or on existing Caltrans owned sites. Caltrans uses external consultants to prepare these risk assessments. Caltrans is also conducting research into lead impacted soil, a particular issue with soil along roadways.

3.1.1 Risk Assessments on Project Sites and Caltrans Owned Parcels

The Committee’s recommendations were evaluated on those aspects of the review and approval process that are conducted by Caltrans on the risk assessment reports. The areas where risk assessment is used include:

Caltrans Owned Parcels: These parcels include sites where soil and groundwater have been impacted by constituents of concern due to past practices; such as sand blast waste under steel bridges and leaking underground fuel tanks on maintenance facilities. In these cases Caltrans is retaining the property and working to ensure that public and worker health and the environment are not adversely impacted by the presence of these constituents. For these sites, risk assessments, including Risk-based Corrective Action (RBCA) assessments, are used to assess the impact of contamination and determine appropriate cleanup action, if necessary. Risk assessments involving lead are reviewed by DTSC.

Excess Parcels: These parcels are first assessed for the presence of contamination, then a determination is made whether the constituent concentrations are sufficient to require cleanup or if the parcel can be sold "as is". A policy is being developed by Caltrans to standardize these decisions. If necessary, risk assessments or RBCA assessments are conducted.

Sites within Project Boundaries: Caltrans purchases these sites as part of the project development process. Risk assessments or RBCA assessments may be performed depending on the severity and extent of contamination, regulatory oversight, and the potential risk to workers and the public. Not all of these sites warrant this level of effort.

Caltrans continually provides internal and external training to staff, to keep staff members abreast of new developments and issues regarding risk assessment. Reports are reviewed internally at the local level and then by a select group of staff at headquarters to maintain consistency. For intricate sites, Caltrans may request a third party review in addition to their own internal review. Additionally, these reports are reviewed by a regulatory agency. At this time, all risk assessment work is contracted out to private consultants. In the future, RBCA reports may be prepared internally by Caltrans staff; all work will be conducted in a manner consistent with current practices.

Risk assessment reports are kept on file in the District and at Headquarters and are available for review. At this time, Caltrans does not have a standard report format that must be followed. The content of a non-RBCA risk assessment report is left up to the consultant provided that current risk assessment guidelines are followed. For a RBCA report the consultants are required to follow the ASTM standard that requires certain items be addressed.

3.1.2 Lead Impacted Soil

Freeway construction projects involving excavation of soils along the shoulder and median areas have encountered lead contamination in surface soils resulting from the historic use of leaded gasoline. This contamination is found along highways with high traffic flow such as those located in San Diego, the San Francisco/Oakland metropolitan area and the Los Angeles Basin. Reliable characterization of the concentration and lateral and vertical extent of this lead contamination is important since the results of the characterization will affect the design and execution of the construction project. If the characterization is inaccurate, the construction project can experience significant delays and increased costs.

The fraction of excavated soil containing total lead in excess of the total threshold limit concentration (TTLC, 1000 mg/kg) or containing soluble lead in excess of the soluble threshold limit concentration (STLC, 5 mg/L) is legally a hazardous waste. However, the Human and Ecological Risk Division (formerly Office of Scientific Affairs) within the Department of Toxic Substances Control (DTSC) determined that this soil can be managed on Caltrans rights of way in a manner that presents no significant threat to human health or the environment under certain conditions. This approach is consistently used in issuing Variances to Caltrans Districts 4, 6, 7, 8, 11, and 12 and addresses regulatory requirements and the protection of human health.

Caltrans contracted a private consulting firm to evaluate the fate and transport of lead in soil to determine the potential for lead in soil to leach to groundwater. A comprehensive literature review found that lead was not leachable except under certain conditions. Caltrans has applied to SWRCB for a Caltrans Statewide NPDES/WDR Permit for stormwater and non-stormwater discharge.

Currently, Caltrans implements a recommended sampling strategy for consistency between Districts which provides guidance on sample location and depth. Caltrans samples soils for the presence of total and soluble lead in advance of construction projects and has generated a large body of information for major metropolitan areas in California. Caltrans contracted with a private consulting firm to conduct a statistical analysis on these data that will support development of a tiered lead contamination sampling methodology. This lead contamination sampling methodology may be used pending a third party review of the statistical approach.

3.2 Air Quality Research (Office of Environmental Engineering)

Federal conformity rules require that state agencies responsible for approval and/or funding of transportation projects ensure that such projects conform to an approved or promulgated State implementation plan and to all applicable State and Federal air quality standards. Because of this requirement, Caltrans needs to evaluate the potential local impacts of carbon monoxide and particulate matter from a project

Caltrans uses computer models to evaluate potential impacts. Because of the need to heavily rely on the model output, Caltrans continually undertakes research projects to evaluate receptor locations, emission models, and model input parameters. Each of these research projects is developed by staff at the University of California at Davis and the methodology is peer reviewed by other members of the faculty. Results are also reviewed internally, by staff at Caltrans and if published in a journal, the research goes through another level of review. Results of the research projects are distributed to staff at the Air Resources Board, Cal/EPA, US EPA and Metropolitan Planning Organizations. The rest of this section describes research projects aimed at using the best science available to predict potential impacts of a project.

3.2.1 Selecting Receptor Sites

The receptor-siting criteria suggested by Caltrans recognize the concept of exposure to levels of carbon monoxide that have a reasonable likelihood of leading to a carbon monoxide hemoglobin level greater than that achieved by current standards. Caltrans methodology moves the receptor, for evaluating an 8-hour exposure, from the location recommended by the US EPA to a location where a person could actually be exposed to carbon monoxide for an 8-hour period. The receptor locations in US EPA’s siting guidance tend to predict problems when none actually exist. Caltrans believes this happens because the receptors are being located in areas where exposure doesn’t actually occur.

Caltrans based its recommendations for receptor siting on the data used to develop the carbon monoxide ambient air quality standards and the Denver Carbon Monoxide Exposure Study. This methodology was prepared for Caltrans by the University of California at Davis. Caltrans and the US EPA are discussing the recommendations made by Caltrans and determining if the US EPA will change its siting guidance document.

3.2.2 Evaluation of Two Carbon Monoxide Intersection Models

Microscale air dispersion models are essential tools used to assess the impacts of carbon monoxide on air quality. Two of the most widely used dispersion models are CALINE4 and CAL3QHC 2.0. Recently, there has been a growing concern that some of the algorithms built into CALINE4, implemented to perform intersection analyses, are not appropriate for today’s vehicle fleet. As part of Caltrans study, a new modeling technique was developed that uses CALINE4 combined with an "average speed" to analyze intersections. The calculation of the "average speed" is based on the algorithms given in the Highway Capacity Manual and requires traffic volume, percentage of red time and average approach speed. In the new modeling technique, the built-in CALINE4 intersection algorithms are not used.

A comparison of the performance of this new CALINE4 modeling approach and CAL3QHC 2.0 was made using the same data set used by US EPA. Common statistical measures were used to assess model performance including scatter plots, average residual, root-mean-square-error and correlation coefficient. The results indicate that the carbon monoxide concentrations predicted by the new approach using CALINE4 are comparable to those predicted using CAL3QHC 2.0. An algorithm was developed by Caltrans for implementation in CALINE4 to take into account the potential effects of buoyancy.

Caltrans has also conducted specific research on uncertainty in fate and transport model. One study evaluated the ability of the models to estimate modeling buoyancy. An additional research project being undertaken based on the buoyancy experiment, is evaluating situations in which the source is not at ground level.

3.2.3 Transportation Project Level Carbon Monoxide Analysis Protocol

Caltrans is preparing a carbon monoxide analysis protocol. Procedures and guidelines are provided in this project-level protocol for use by agencies that sponsor transportation projects, to evaluate the potential local level carbon monoxide impacts of a project. The procedures and guidelines comply with the necessary regulations. Upon approval, the procedures and guidelines described will constitute a protocol that is intended to replace the procedures for determining localized carbon monoxide concentrations that are given in 40 CFR section 93.131.

The new protocol proposes a streamlined, tiered approach for determining conformity. The overall idea of this protocol is to provide a framework for consistency and limit the number of projects which have to run time consuming and expensive, detailed models to determine conformity.

Based on concerns from the regulatory community, additional research is being conducted to determine if the protocol is adequate for addressing Level of Service D intersections.

3.2.4 Emissions Models

To comply with the requirement from the Metropolitan Planning Organizations and the US Department of Transportation, Caltrans uses the California Air Resources Board’s Motor Vehicle Emissions Inventory (MVEI) models to estimate emissions from proposed projects.

Each time the Air Resource Board updates its MVEI, Caltrans evaluates the changes to determine the potential impacts and determines if the new MVEI can still be used to estimate emissions.

3.2.5 Modeling for Particulate Matter (PM)

Caltrans has been required to evaluate the effect of roadway projects on local particulate matter concentrations. This has focused attention on the lack of information on particulate matter emissions from California roadways. Few emission rate studies carried out in the past twenty years collected particulate matter data, and fewer still attempted correlation of particulate matter aerosols with traffic in real systems. Currently, information derived by the US EPA from studies in the mid western United States forms the basis for air quality modeling in every state. However, US EPA’s "AP-42" emission factors were derived in conditions very different from those in California. Areas which are geologically and meteorologically different from California. The use of these emission factors in current air quality models may be inadequate for predicting downwind particulate matter levels.

In 1994, Caltrans contracted with the Air Quality Group at the University of California at Davis to determine if the AP-42 emission factors over estimate the downwind particulate matter levels. The results of this study showed that measured emission factors fall far below the AP-42 emission factors.

1n 1995, the Air Quality Group investigated paved road particulate matter emissions in greater depth. This study included measuring roadway silt loading and monitoring for particulate matter and PM2.5. PM2.5 was included because future PM standards may focus on particles having an aerodynamic diameter of 2.5 µm or less.

The results of the 1995 study show that the measured emissions were very close to the modeled emissions. It is believed that the 1994 study suffered from a sparse data set. The measured silt loadings, though, were much lower than the values found in AP-42. This reinforces the need to use measured roadway silt loading when emission rates are estimated using the AP-42 method. Further studies are needed to expand the database of roadway silt loading data for California.

3.3 Storm Water Monitoring (Office of Environmental Engineering)

Caltrans monitors the concentrations of constituents in storm water. The overall objective of the storm water monitoring program is to comply with their National Discharge Elimination System (NPDES) permits. In turn, the NPDES program is designed to protect human health and the environment. This program was included in the evaluation even though no quantitative risk assessments are conducted.

3.3.1 Program Overview

Caltrans is committed to implementing storm water management practices to manage pollutants as required by applicable legislation and regulations and is applying for a statewide NPDES storm water permit.

Caltrans has determined that a single NPDES storm water permit and a comprehensive and consistent statewide storm water management plan (SWMP) would be the most effective approach to addressing its activities statewide. Compliance with the permit could then be attained by implementation of the SWMP. Caltrans developed its SWMP, in conjunction with senior faculty members from the University of California at Davis, California State University at Sacramento, and University of California at Riverside, to provide a framework for consistent and efficient implementation of storm water management practices in all districts. This approach will facilitate the development of more standardized and uniform internal guidance, contracts, and training. Included in the SWMP is a time schedule for implementing the SWMP elements. Although the statewide NPDES permit will be issued by the State Water Resources Control Board (SWRCB), Caltrans will continue to work closely with the RWQCB.

Caltrans’ overall strategy for maintaining compliance with all aspects of its proposed statewide NPDES storm water permit and its corresponding SWMP involves the use of a process of continuous improvement and refinement of its storm water management program. A 3-Year Storm Water Monitoring Action Plan (Action Plan) is being prepared by Woodward-Clyde in conjunction with the California State University at Sacramento and University of California at Davis to implement the Planning-Support Monitoring and Evaluation Program described in the SWMP. A draft Action Plan was submitted to the SWRCB for review in the Spring of 1997.

The Planning-Support Monitoring and Evaluation Program is a program of applied research designed for continuous improvement and refinement of the storm water monitoring program. The overall goals of the program are to: advance the state of knowledge regarding management of storm water from highways and related facilities, provide a sound basis for redirecting or refining aspects of the storm water management program, and recommend ways to revise the SWMP as needed.

This program consists of eight interrelated information-gathering activities that Caltrans will conduct to gain insights into storm water-related water quality issues and pollution control issues. These eight activities include the following: 1) identify receiving waters and constituents of concern, 2) identify factors that affect the concentration and loads of constituents of concern in highway runoff, 3) examine physical and chemical mechanisms that affect mobilization, transport, and transformation of constituents in highway runoff, 4) develop a methodology for prioritizing highway facilities, 5) prioritize highway drainage segments, 6) define types of locations that warrant focused control efforts, 7) identify practices to be evaluated and plan the pilot studies, and 8) implement and monitor the effectiveness of candidate practices through pilot studies. The knowledge gained from these activities will help Caltrans management understand how to establish priorities for allocating resources available for storm water management and to periodically revise and refine Best Management Practices, Caltrans’ overall storm water management program, and/or the SWMP, as needed.

The Action Plan consists of studies that have been designed to meet the objectives of one or more of the eight activities that form the core of this program. These studies can be thought of as the "building blocks" that Caltrans will use to gain the information and understanding it needs to meet its stated goals. Every study is reviewed by the Oversight Committee (made up of senior faculty members from the California State University at Sacramento and University of California at Davis) before being included in the Action Plan. Additionally, Caltrans plans on engaging the regulatory community for research ideas and review comments. The Action Plan also presents the process that will be used to revise and update this plan each year and a tentative schedule for conducting these studies. Studies are currently underway to meet these objectives.

3.3.2 Data Quality Issues

Caltrans has been conducting various types of field monitoring at the District level (e.g., highway runoff characterization, source characterization, evaluation of storm water management practices) to comply with the NPDES Permits issued by various RWQCBs. In order to improve the quality, consistency, and comparability of data that are being collected by the Districts, Caltrans contracted Woodward-Clyde to independently review current practices and provide recommendations for improvement. Woodward-Clyde evaluated the following components of the storm water monitoring program: monitoring sites and sampling locations, storm selection, storm water monitoring preparation, sample collection, monitoring frequency, sample analysis, QA/QC sample collection and independent data review.

3.3.3 Best Management Practices

Senior Caltrans personnel, with input from RWQCB staff, personnel of several municipal storm water management programs, and representatives from the Natural Resources Defense Council, performed an evaluation to decide which storm water management practices should be recommended as Best Management Practices for broad application. The storm water management practices were evaluated and scored, and were then rated by tallying the scores for the three evaluation criteria (pollution control benefit, implementation feasibility, and economic feasibility). These Best Management Practices will continuously be evaluated and refined.

3.3.4 Training and Public Education and Participation Program

The SWMP presents three types of training: personnel training, informational exchanges with construction contractors, and public education and participation.

The training courses included in the Personnel Training Program will provide a comprehensive review of storm water pollution prevention concepts and practices. The curriculum will consist of three courses: 1) storm water management for maintenance activities, 2) storm water management related to construction sites, and 3) storm water management for project development. During the first year of implementation, Caltrans personnel will attend training courses that are relevant to their job classification and responsibilities. Refresher courses will be held every four years. Caltrans personnel and outside consultants will provide this training.

The purpose of the informational exchanges is to teach Caltrans construction contractors about the following topics: 1) the provisions, conditions, and requirements of the permit that apply to their projects, 2) the availability of guidance material prepared by Caltrans for construction contractors and 3) general responsibilities of construction contractors regarding implementation of the SWMP, the requirements of a SWPPP and how to prepare a SWPPP. Two types of sessions will be used: 1) storm water permit compliance requirements - pre bid meeting and 2) storm water permit compliance requirements - pre construction meeting. Topics included in these sessions will be updated as needed to reflect modifications to the SWMP. Caltrans personnel and outside consultants will provide this training.

In addition to the training sessions discussed above, Caltrans will periodically make presentations at the Association of General Contractors (AGC) meetings and other contractor group meetings. The presentations will focus upon issues related to implementation of the SWMP. Caltrans will annually conduct a workshop with AGC to discuss storm water issues and Caltrans requirements. Additionally, Caltrans will annually prepare and distribute an information newsletter to inform construction contractors of recent storm water quality developments and requirements for Caltrans Construction Projects.

The Public Education and Participation Program will provide a variety of practices for educating the public about the importance of managing storm water. Caltrans has existing programs to educate the public about storm water problems related to illegal dumping of litter and debris. One such program is the "Adopt a Highway/Adopt a Wall" program. Additionally, Caltrans will install "No Dumping", "litter fine", and "cover load" signs as well as stencil storm drain inlets at Caltrans owned locations. Caltrans will also commit from $100,000 to $150,000 annually (beginning Spring 1997) to a public education grant program. Public education programs that receive funding from this grant program will be required to submit a report of the results and effectiveness of the public education program that was implemented. The report will also include recommendations on whether to continue the program or methods for enhancing the program that was implemented.

These training programs will keep people up to date on the current standards, involve the public and private sector. The programs also present ways to evaluate the effectiveness of the training programs.

3.3.5 Sampling Analysis and Collection Plan

As part of the statewide NPDES storm water permit, private consultants prepared a sampling collection and analysis plan. This manual was submitted to the regulatory community for review on April 4, 1997. Prior to submission to the regulatory community, the manual was peer reviewed by professors at California State University at Sacramento, Caltrans staff, and external private consultants.

The manual is designed and organized to provide a comprehensive, step-by-step description of the processes used to plan a successful water quality monitoring program, including a thorough QA/QC data evaluation, specific to runoff from transportation-related facilities. It is essential that monitoring data are collected so as to ensure that the data are accurate, precise, and scientifically defensible. It is also important for monitoring programs to be conducted in a consistent manner, to provide for data comparability throughout the Districts. This will then ensure that regional differences, if any, can be accurately addressed, and that the data can be utilized in a statewide database.

The focus of this guidance manual is on monitoring protocols that are used to plan and implement sampling and analysis for chemical and physical constituents, as part of a water quality monitoring program. The emphasis throughout the manual is on storm water monitoring that will provide data to support the planning functions of the SWMP. Water quality constituents that may be present in highway runoff generally have been identified by previous monitoring efforts. Therefore, the statewide program takes a slightly different approach to monitoring and instead of just monitoring for what is present, Caltrans will be:

Monitoring to discern the specific sources, transport mechanisms, and fate of constituents known to be present in transportation facility runoff, and

Monitoring to determine which control measures are most effective in reducing the discharge of constituents that may have an adverse impact on receiving water quality.

3.3.6 Methyl Tertiary Butyl Ether (MTBE) Monitoring

As part of its proactive stance, Caltrans voluntarily included MTBE in its FY 1996/1997 storm water sampling at three sites in District 7. The purpose of this monitoring is to discover if MTBE is present in rainfall and to what extent, if any, it is impacting storm water runoff. Depending on the results in District 7, MTBE may be included in the sampling of all Districts. Unfortunately, no data were collected during the FY 1996/1997 season due to lack of rain. This program will be continued in the FY 1997/1998 season.

Caltrans has also contributed to Air Board Research needs by addressing analytical issues with laboratory false positives of MTBE in water.

Chapter 4.0 Caltrans Implementation Plan

A summary of specific recommendations, made by the risk assessment advisory committee, for the eight categories.

Table 4.1 presents Caltrans Implementation Plan. The reader is referred to the SWMP for time lines regarding storm water monitoring activities. There are no timelines for the Air Quality Research activities or Quantitative Risk Assessments as these projects are conducted on an as needed basis.

Table 4.1 Caltrans Implementation Plan

Category	Items to Implement
1. Training Continuous education is needed to be certain that expert personnel keep abreast of new developments. With rapid change, one's university education is inadequate to sustain a career without frequent updating. Mechanisms such as two-way temporary staff exchange programs, forums and trainings should be encouraged.	OEE Implement training program outlined in the Statewide Storm Water Management Plan (SWMP), including personnel training, informational exchanges with construction contractors, and public education and participation. Continue to use private consulting firm and university staff in house for their expertise. OHWM Send staff members to workshops, meetings and conferences as well as having internal seminars.
2. Data Management Institute measures for quality control of data in databases and data being added to the databases. For example, the quality of data relies, in part, on the sampling strategy employed. Additionally, improve the accessibility of data to all interested parties.	OEE Implement storm water Sampling Analysis and Collection Plan, which provides a comprehensive, step-by-step description of the process to be used by every District. Create a database and make data available via the Internet OHWM Evaluate the recommendations made for the lead sampling program for their usability.
3. Peer Review Develop a formalized policy for internal and external peer review of program activities.	OEE Continue to have project designs and outcomes reviewed by staff of private consulting firms, universities, and regulatory agencies. OHWM Continue to use regulatory agencies and objective private consulting firms in the review process.
4. Receptor Based Exposure Assessments Receptor-based exposure assessment is a powerful tool that could help to prioritize efforts to reduce exposures and protect public health. Cal/EPA should acknowledge the uncertainty that results from the reliance on scenario based exposure assessments.	OEE Evaluate the necessity for further research efforts regarding receptor locations for the carbon monoxide program. OHWM Not Applicable
5. Exposure/Fate and Transport Models A well run modeling exercise provides our best view into the future. More effort is needed to validate models with real experimental data. In assessing transport and dispersion models, the quality and characteristics of input data to the models, such as emissions data and dispersion parameters, should be considered in addition to the validity of the models themselves.	OEE Conduct additional research projects to evaluate the validity of air models and their input parameters as needed. OHWM Evaluate the applicability of models to site specific conditions as needed.
6. Communication/Information Sharing Efforts towards consistency and harmonization between boards and departments and their federal counterparts have begun, appear to be useful, and should be encouraged.	OEE Continue to share work product information with regulatory agencies. OHWM Continue to share work product information with regulatory agencies.
7. Decision Making and Risk Management Policies Policies and procedures for addressing the translation or risk assessment uncertainties into risk management policy should be developed. Continue to look for, and implement, ways of involving risk managers and stakeholders in risk assessment, including the development of guidelines, assessments, workshops, and reviews.	OEE Not Applicable. OHWM Work towards finalizing the draft guidance document that will be used to close site.
8. Process Improvement Seek out and implement ways of simplifying and streamlining the process of risk assessments.	OEE Implement the Storm Water Monitoring Plan and Sampling Analysis and Collection Plan, both of which contain methods for yearly reflection and modification. OHWM Work towards finalizing the draft guidance document that will be used to close Sites.

 

1. Training

It is imperative that the public have confidence that Cal/EPA human health risk assessments reflect the best possible scientific judgments. Therefore, it is recommended that an overarching administrative structure be established that has as a principal duty, stewardship for selecting areas where the application of new or existing knowledge could enhance the certainty of scientific judgment as to human health risks.

Cal/EPA should do an assessment, both of activities and of needs, relative to staffing, manpower, and expertise. This could include cross-training and retraining opportunities for present staff where appropriate.

Continue to look for, and implement ways of involving risk managers and stakeholders in risk assessment, including the development of guidelines, assessments themselves, workshops, and reviews. Particularly strive for involvement as early as possible in the process.

Continuous education is needed to be certain that Cal/EPA’s most expert personnel keep abreast of new developments and that front-line personnel are educated about the availability of advanced, yet robust opportunities for improving fate and transport modeling capabilities. Society is coming to a deeper understanding of environmental processes over time, and that deeper understanding needs to be reflected in regulatory processes. With rapid change, one’s university education is inadequate to sustain a career without frequent updating. Agencies can remain current by growing: new ideas enter with new staff. Significant growth at Cal/EPA appears unlikely for the foreseeable future, so other mechanisms must be sought. Cal/EPA management must recognize that it is a legitimate activity for staff to spend at least a few hours per week engaging in continuing education activities. The Agency should consider implementing mechanisms such as two-way temporary staff exchange programs, creating forums, individual training.

2. Data Management

Review the present data collection/data management effort for overlap.

Improve accessibility of present data.

Institute measures for quality control of data in the databases, and that being added to the databases. For example, the quality of monitoring data relies, in major part, on the sampling strategy employed – an area requiring continuing attention by the units responsible for the monitoring activity.

3. Peer Review

Cal/EPA should develop a formalized policy for internal and external peer review of its activities. It should identify the goals and objectives of the program and Cal/EPA should design a program to meet those objectives.

The systems currently in place within Cal/EPA for reviewing assessments need to be reexamined; if necessary, new systems should be implemented to ensure consistency of practice.

4. Receptor Based Exposure Assessments

Receptor-based exposure assessment is a powerful tool that could help Cal/EPA prioritize its efforts to reduce exposures and protect public health. To make productive use of this tool, we recommend the establishment of an external advisory group at the Agency level. This cross-cutting group would identify which issues and problems are best addressed with a receptor-based exposure assessment approach. Further, this group would oversee the introduction of receptor-based exposure assessment into the diverse programs of Cal/EPA in a coordinated and consistent manner.

Additional monitoring of human exposures is needed to complement the efforts to implement receptor-oriented exposure models. For example, in addition to a fixed-station air toxics network, it would be beneficial to develop an ongoing personal exposure monitoring program. Such data should be used to validate exposure models.

First, Cal/EPA should require an explicit statement of the nature of the exposure assessment related to the purpose of the overall risk assessment being performed. Such a statement (often called a problem formulation statement) should clearly state whether the estimate is intended to be an unbiased characterization of individual’s dose rates or a conservatively biased estimate that should be viewed as an estimate of the upper bound of exposure. Second, the Agency should provide guidance on how the conservative biases of screening-risk estimates should be interpreted by risk managers and the general public. Third, when performing risk/benefit or risk/risk comparisons, Cal/EPA should strive for risk estimates that are unbiased and that take into account all assumptions inherent in the exposure assessment.

Cal/EPA should acknowledge the uncertainty that results from the reliance on scenario-based exposure assessments and the biases in exposure estimates that are introduced by the adoption of simplifications in the design and use of scenarios. Where practical, the Agency should perform personal exposure monitoring surveys to determine the frequency distribution of actual dose rates and confirm the results of scenario-based exposure assessments.

Where Cal/EPA requires the use of specific scenarios, it should provide justification as to why the specific scenario is appropriate or necessary at a site. This justification should include a discussion of the land use and behavioral assumptions implicit in the scenario.

Cal/EPA should strike a new balance between exposure monitoring and ambient monitoring by devoting more attention to exposure monitoring. The new receptor-oriented approaches permit the exposures from more than one environmental medium to be measure simultaneously in a single field study, making them especially appropriate for Cal/EPA’s multimedia mission.

5. Exposure/Fate and Transport Models

Procedures should be developed to use such techniques as working papers, white papers (narrow issues) and guidelines to move new scientific developments into regulatory practice.

In adopting models or default assumptions, or approaches to exposure assessment, Cal/EPA should design mechanisms for updates and changes. Also, mechanisms by which Cal/EPA scientists are kept informed of scientific developments are needed. Providing opportunities for Cal/EPA staff to attend scientific meetings, workshops, seminars, etc., is very important.

Cal/EPA should assert leadership in setting and maintaining high modeling standards. A well-run modeling exercise by a competent modeler provides our best view into the future. Although Cal/EPA’s principal focus is not in model development, the Agency does have a responsibility to deep abreast of advances in fate and transport modeling and to inform the regulated community about which models are relevant and which are proven less useful. If the State of California, through Cal/EPA, insists on high standards, the models developed within the State will generate expertise that can be exported. California has several premier research laboratories, world-class universities, and a strong environmental consulting industry. Cal/EPA can facilitate the movement of fate and transport models out of the research institutions and into use.

More effort is needed to validate models with real experimental data. The Committee is concerned about the potential erosion of effort to monitor concentrations and exposures because of budget constraints.

Cal/EPA should seriously explore incorporating stochastic approaches, as appropriate, in their risk assessment activities beyond the welcome introduction of CalTOX. Uncertainty and variability are hard facts of environmental sampling and assessment. Stochastic modeling approaches that produce distributional information about possible media concentrations and the corresponding risks constitute the best available means to account for the effects of uncertainty and variability.

Cal/EPA should work towards incorporating chemical breakdown schemes and focus on products of reaction as it further develops its modeling capability.

Cal/EPA should increase its knowledge of developments in groundwater modeling and provide encouragement to modelers to use these improved models where justified by the situation. This should not be construed, however, as a mandate to use advanced models, which may be costly and difficult to understand, when the importance of the risk management decision does not require them or when screening models are sufficient to dismiss risks as insignificant.

It is important that accurate vadose zone models be available. It is recommended that Cal/EPA assert leadership in fostering dialogue between different departments within Cal/EPA, academia, and the regulated community with the objectives of (a) identifying parameters that should impact vadose zone model development and selection, and (b) identifying specific application and models that appear to provide better estimates. The Agency should also provide more explicit guidance to modelers as the acceptability of vadose zone models, or to make it clear how to predict fate and transport in the vadose zone if not with mathematical models.

Cal/EPA should develop guidance for modelers on how to provide uncertainty characterizations that are sufficiently quantitative to permit good risk management decisions.

Cal/EPA should explore the application of stochastic methods, including Monte Carlo Simulation, to help define the probability of failure of remedial measures, such as pump-and-treat technologies.

Cal/EPA should couple the large amount of monitoring data which it collects on well water and groundwater contamination with modeling efforts, so as to promote validation of groundwater fate and transport models.

The validity and applicability of current fate and transport models recommended by Cal/EPA for atmospheric release of contaminants should be reassessed. This activity should be undertaken by an assembled group of academics, Cal/EPA technical personnel and scientific representatives from the regulated industry. In assessing transport and dispersion models, the quality and characteristics of input data to the models, such as emissions data and dispersion parameters, should be considered in addition to the validity of the models themselves. Risk management decisions for atmospheric releases of toxic air pollutants depend critically on short-range (<10 km) transport and dispersion. Although it is widely believed that the most popular atmospheric dispersion models have been validated within a factor of 2 or 3 for annual average concentrations, the experimental basis for that belief is actually relatively weak. Cal/EPA should consider reevaluating the validity of atmospheric dispersion models to confirm that these models are acceptably accurate for the decisions being made (in comparison to the accuracy of decision tools for other pathways of exposure). If the combination of theoretical considerations and empirical determination is not compelling in this regard, Cal/EPA should look for opportunities to improve the empirical basis for the models, possibly in conjunction with US EPA. For example, tracer

Cal/EPA should increase its knowledge of developments in air quality modeling and provide encouragement to modelers to use these improved models where justified by the situation. This recommendations should not be construed, however, as a mandate to use advanced models, which may be costly and difficult to understand, when the importance of the risk management decision does not require them or when screening models are sufficient to dismiss risks as insignificant. Cal/EPA should also consider further developing fate and transport modeling techniques that could be used in case specific instances where conventional air dispersion modeling is not appropriate, for example in the indoor environment. The US EPA, in conjunction with the American Meteorological Society, has initiated an effort to update the treatment of transport and dispersion in the ISC model. While the new model (AERMOD) will automatically become of the Cal/EPA’s approved models when it becomes publicly available, the Agency should review it and be prepared to recommend its use under appropriate conditions.

Cal/EPA is advised to make surveillance of developments in the science of intermediate fate and transport a continuing priority and to institute procedures for systematic updates of multimedia risk assessment procedures with the goal of improving the accuracy of estimates. To the extent possible within legislative constraints, Cal/EPA should also attempt to cross-fertilize and harmonize procedures across the boards and departments and to use the best of US EPA science to improve its own. In doing so, it should give due consideration to the specifics of California conditions such as precipitation and temperature to be sure that model parameters from US EPA or elsewhere are reasonable in the specific situation being assessed. Finally, Cal/EPA should consider providing for the dissemination of the best science among the boards and departments. Such dissemination could occur through formal continuing education requirements, temporary or permanent reassignment of personnel, regular interdepartmental meetings, newsletters, or other techniques. The most effective combination of techniques may need to be discerned by trial and error. In addition, an implementation plan should be developed for CalTOX with a timetable and objectives.

Cal/EPA should review the effect of choices of assumptions, models, use of quantitative uncertainty analysis, etc., on decision outcomes, including a review of the impact of assumptions in the CalTOX program.

The uncertainties in models, data sets, and parameters and their relative contributions to total uncertainty in a risk assessment should be reported in written risk assessment documents.

When different models may be employed in a risk analysis, perhaps leading to different conclusions, parameter uncertainty should be analyzed at a similar level of detail for all the models.

Cal/EPA should more fully communicate the impacts of model and parameter choice in the risk assessment. How model uncertainty was accounted for should be discussed in the final characterization.

6. Communication/Information Sharing

Efforts towards consistency and harmonization between Cal/EPA boards and departments and their federal counterparts have begun, appear to be useful, and should be encouraged.

In order to facilitate consistency and harmonization in the practice of risk assessment at Cal/EPA, an internal agency working group should be established whose specific charge is to insure agency-wide consistency.

7. Decision Making and Risk Management Policies

An agency-wide effort should be undertaken to develop policies and procedures for addressing the translation of risk assessment uncertainties into risk management policy. Consideration should be given to replacing single value or "bright line" criteria with strategies that acknowledge the range of risk uncertainty and allow cost and benefits within the uncertainty band to be dealt with at a local level.

Cal/EPA needs to establish a mechanism for prioritizing candidates for full risk assessment, so that resources are spent primarily on the major problems.

Cal/EPA should clearly articulate a set of principles for justifying independent assessments for chemicals/locations which other agencies have assessed previously.

The public and interested stakeholders should be involved early in the risk assessment process and maintain involvement at key decision points throughout the process.

The extent to which Cal/EPA’s practices are aligned with their broad mission should be reexamined. Such an activity may require articulating a clear mission for the Agency. The current practice of fate and transport assessments may only require incremental improvement if the primary goal is protection of environmental resources, such as air or water. However, if the Agency’s primary mission is environmental health protection, then it needs to take substantial, fundamental steps to improve its understanding of the relationships between fate and transport and human exposure.

8. Process Improvement

Efforts towards consistency and harmonization between Cal/EPA boards and departments and their federal counterparts have begun, appear to be useful, and should be encouraged.

In order to facilitate consistency and harmonization in the practice of risk assessment at Cal/EPA, an internal agency working group should be established whose specific charge is to insure agency-wide consistency.

Cal/EPA needs to seek out and implement ways to simplify and streamline the process of risk assessment for assessments conducted in-house and those required of outside entities.

Cal/EPA need to establish measures of success for gauging the effectiveness of efforts to streamline and simplify.

Chemical Reference

• Methyl Tertiary Butyl Ether