Measuring water ingestion from spray exposures.

Area of Science:

• Environmental Health
• Toxicology
• Risk Assessment

Background:

• Quantitative exposure data for non-drinking water uses are scarce, hindering accurate health risk assessments.
• Regulatory agencies rely on estimates for policies concerning non-potable recycled water treatment.
• Need for reliable methods to measure inadvertent water ingestion in recreational and occupational settings.

Purpose of the Study:

• To adapt and validate the use of cyanuric acid as a tracer for quantifying inadvertent ingestion of small water volumes.
• To assess water ingestion during recreational activities involving spray exposure.
• To generate empirical data for improving health risk assessments of non-potable water exposure.

Main Methods:

• Utilized cyanuric acid (700-1000 mg/L) as a tracer chemical in an experimental spray exposure.
• Measured inadvertent water ingestion in participants during a 10-minute car wash activity with a high-pressure spray.
• Assessed skin absorption of cyanuric acid under experimental conditions.

Main Results:

• Quantified inadvertent water ingestion in nearly 70% of participants during the car wash activity.
• Measured ingestion volumes ranged from 0.06 to 3.79 mL.
• Demonstrated negligible skin absorption of cyanuric acid under the tested conditions.

Conclusions:

• The cyanuric acid tracer method effectively quantifies small volumes of inadvertently ingested water from spray exposures.
• This method is applicable to various non-potable water use activities, providing crucial data for risk assessment.
• Empirical exposure data enhance regulatory confidence in managing public health risks associated with non-potable water.