Q. How does Biobot analyze high risk substances in wastewater?
Since traces of high risk substances are excreted in urine and feces, wastewater is an ideal medium for capturing community trends in high risk substances consumption. Biobot employs highly sensitive laboratory assays to measure the concentration of HRS markers in wastewater, which enables estimates of community substance use.
Substances are appropriate wastewater-based epidemiology (WBE) targets if:
- a chemical signature of a substance, called a biomarker, is consistently measurable in wastewater, and;
- resulting data are easily interpretable, specific, and actionable.
Biobot measures parent drugs and metabolites as shown in the figure below. After ingestion of a parent drug, small amounts of the drug, along with metabolites (chemical signatures of the parent drug being processed by the human body), are present in wastewater. By measuring both parent drugs and their respective metabolites, we can distinguish between changes in community substance use and environmental events such as flushing down the drain (which do not reflect substance use).
Prior to processing, quality control standards are added to each sample to correct for sample loss and deterioration during analysis. The method, termed “isotope-dilution quantitation,” is a gold standard for the identification and quantification of organic substances in wastewater. After removing large particles by filtration, samples are concentrated using solid-phase extraction prior to quantitative analysis by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS).
Substance consumption is calculated by normalizing measured substance concentration (i.e., mass substance per volume wastewater) to the approximate influent flow and population served, which are both reported by customers. By multiplying the measured concentration (mg/mL) by the influent flow rate (mL/day) and dividing by catchment population, Biobot estimates community consumption in milligrams of substance per 1,000 people.