We encounter exogenous chemicals at every turn - in water, air, soil, consumer products, food, and drugs, at home, outdoors, and in the workplace. Toxicologic data on the effects of chemicals are frequently generated through controlled studies of laboratory animals, such as rats and guinea pigs, but are also gathered through observation of humans exposed deliberately (for example, to sulfur dioxide), unintentionally (for example, to water pollutants or food contaminants), or knowingly (for example, to a solvent in the workplace). Epidemiologic studies of exposed populations also give useful information.
Questions regarding the safety of exposure to environmental chemicals may arise before or after the fact. A drug manufacturer, for instance, may want to know at what concentration in air a reactant might cause injury during a brief, acute exposure, such as might occur during breakdown of manufacturing equipment, to aid in planning for emergencies. As another example, people who discover that their drinking water has been contaminated for many years by perchlorate may want to know whether their past or current health problems were caused by that exposure.
Toxicity of a mineral-processing agent
For the State of Vermont, Cambridge Environmental was the lead contractor for the state's most intensive and extensive evaluation of the environmental and health impacts of industrial waste management. We discovered the first instance of groundwater contamination by a teratogenic (i.e., birth defect-inducing) chemical, aminoethylethanolamine, researched the toxicity of this agent, and developed a water quality guideline for this chemical that was then adopted by the state.
High Production Volume Chemicals
U.S. EPA initiated the High Production Volume Chemical Program in order to gather, generate, and make public data on chemicals used in high volumes in this country. On behalf of the Ethanol HPV Challenge Consortium, Cambridge Environmental Inc. prepared the robust summary, test plan, and test plan justification for ethanol. These work products were submitted to EPA's HPV Challenge program as a voluntary effort by the consortium, and were deemed to meet all program requirements by the Agency. Preparation of the robust summary required identification, review, and abstraction of environmental fate and toxicity data including acute toxicity to fish, acute toxicity to aquatic plants, acute toxicity to aquatic invertebrates, and various mammalian toxicity endpoints, following Agency guidance. All data, including experimental design, results, NOELs, LOELs, statistical methods, and conclusions, were input into software developed by EPA. We prepared a summary document, based on the robust data summary, describing the adequacy of the environmental fate, environmental toxicity, and mammalian toxicity data, summarizing results, citing recent technical literature reviewing toxicity endpoints, and judging whether additional testing was needed. The robust summary, test plan, test plan justification, public comments, and EPA comments can be viewed or downloaded at http://www.epa.gov/chemrtk/pubs/summaries/ethanol/c12981tc.htm.
Birth defects and industrial chemicals
For a group of manufacturers in the high-technology industry, Cambridge Environmental conducted extensive reviews of the reproductive and developmental toxicity of numerous chemicals to which workers may have been exposed. Developmental toxicity, or the ability of a chemical to adversely affect fetal development, was of concern because of the occurrence of birth defects in some children of workers. We exhaustively searched the open and "gray" literature for toxicologic, epidemiologic, and other data describing the effects of the industrial chemicals on humans or laboratory animals, and assembled this information in a form useful to the clients.
Asthma and short-term exposure to sulfur dioxide (SO2)
Cambridge Environmental evaluated the technical bases of U.S. EPA's 2009 revision of the Primary National Ambient Air Quality Standard (NAAQS) for sulfur dioxide (SO2). We identified and, to the extent possible, corrected key analytical problems, and demonstrated the consequences of the corrected values with respect to health policy-making.
Asphalt fumes and related mixtures and chemicals
Since 1997, Cambridge Environmental toxicologists, epidemiologists, and engineers have served as advisors to the makers and users of hot-mix asphalt. We have been involved in the design and interpretation of applied research regarding asphalt fume exposure assessment and toxicology. We have submitted detailed comments to (i) the National Institute of Occupational Safety and Health (NIOSH) on health effects issues surrounding asphalt fumes, and (ii) the U.S. EPA regarding the magnitude and nature of hazardous air pollutant emissions that may occur when hot-mix asphalt is loaded onto trucks. We have performed detailed estimates of hot-mix asphalt plant emissions, used computer-based models to predict the dispersion and dilution of these pollutants in the environment, compared both the emissions and predicted concentrations with ambient measurements, and assessed the potential for exposures to the pollutants to lead to adverse health effects.