Health Risk Assessments Services

Exposure Assessment Modeling
Waterstone creates and refines exposure scenarios that are site specific and appropriate to current and/or future land use. Waterstone has expertise in the area of fate and transport and exposure assessment modeling, including agency-derived modeling calculations, such as the Attenuation Factor fate and transport model used by the Regional Water Quality Control Board, the County of San Diego Site Assessment Manual Vapor Model and the Johnson and Ettinger Model. Waterstone has also created fate and transport models in conjunction with risk assessment for unique sites. Exposure assessment modeling can be applied to: 1. Human Health Risk Assessment – Determination of site-specific pathways of exposure necessary in the calculation of chemical intake 2. Litigation / Toxic Tort – Assessment of the potential for and amount of exposure to a chemical(s) to determine adverse health effects.

Human Health Risk Assessments and Health-Based Clean-up Level
Determination
Risk assessments are a critical component of environmental regulatory decisions that directly impact the cost and timing associated with environmental closure of a site. The results of these analyses help regulators determine the need for and nature of required remedial actions at hazardous waste sites or other sites with chemical impacts. Risk assessments are frequently used to derive cleanup levels by calculating the health risk of residual chemical compounds left in place. This type of calculation is especially important in Brownfields site closures where mitigation to “non-detect” levels of chemicals are not necessary to protect human health and, in many cases, are not feasible. Risk assessment results are also used by regulators to assist in permitting new facilities and in developing closure plans for solid waste management units and facilities that are going out of service. Waterstone toxicologists have performed and reviewed over 100 multi-pathway risk assessments and have derived risk-based remediation goals for hazardous waste sites and facilities impacted by chemical compounds under a variety of federal and state regulatory frameworks. Our services in this area include:

1. Risk assessment strategy development and review
2. Comprehensive human health multi-pathway risk assessments
3. Risk assessments for school sites
4. Screening level risk assessments
5. Derivation of health-based cleanup levels

Health-Based Remedial Investigation Development
Waterstone designs focused site investigations that support the appropriate calculation of human health risk posed by residual chemical compounds. This type of calculation is especially important in Brownfield site closures where mitigation to “non-detect” concentrations of chemicals are not necessary to protect human health and, in many cases, may not be feasible. Our multidisciplinary staff of chemists, engineers, geologists, hydro-geologists, soil scientists, and toxicologists works together to design remedial investigations that provide a baseline that is protective of human health and groundwater and reduces future liability to the land owner. Through these methods, Waterstone’s clients are able to achieve their business and strategic objectives and meet the constraints posed by regulatory requirements. Waterstone’s services in this area include:

1. Regulatory strategy identification – Waterstone aids the client in the identification of the appropriate oversight agency to achieve environmental and business objectives. Investigations are specifically focused on complying with the specific federal, state, and/or local risk assessment requirements (such as US EPA, DTSC and OEHHA requirements)
2. Field investigation design and program management – Field investigations are designed to support a risk assessment scenario that is appropriate to the site. The risk assessment can be designed to realistically or conservatively calculate the health and groundwater risks associated with residual chemical compounds. This process can occur either before, during, or after remediation or other mitigation efforts.
3. Data management / database development - Quality assurance and quality control (QA/QC) are vital parts of the risk assessment process. QA/QC of data is critical to ensure that calculated health risks are based on accurate information. Waterstone has developed an impressive and tested system for database management of risk assessment information to ensure that repetitious tasks are avoided. Our unique database management system has allowed us to significantly reduce the cost of risk assessment services.

Occupational Toxicology Evaluation
Waterstone toxicologists investigate health effects related to occupational exposures by using scientifically derived cancer-risk and health hazard calculations. For many chemicals, these calculations are provided by federal agencies, such as the US EPA. Waterstone toxicologists also possess the expertise to derive occupational exposure limits for less common chemicals. These calculations can be applied to:

1. Litigation Support – Integration of epidemiology, toxicology, exposure assessment, and industrial hygiene information to assess potential for work related diseases
2. Hazard Communication – Preparation of quality Material Safety Data Sheets (MSDSs)
3. Risk Communication – Provision of training courses to employees regarding safe use of hazardous chemicals
4. Product liability management – Using potential for occupational health effects to provide chemical usage, storage, and handling procedures.