Toxicological analysis of samples of Dillo Dirt™ and Class B biosolids collected two years ago at Austin Water Utility's Hornsby Bend Biosolids Management Facility detected no risk to human health.
The samples (two each of compost and biosolids) were tested for chemicals, including volatile and semi-volatile organic compounds, and organochlorinated pesticides. This testing was above and beyond any required by state and federal regulations and is part of the Utility's commitment to ensuring the safety of Hornsby Bend's biosolids products.
Janet Pichette, Environmental Toxicologist with the Austin/Travis County Health and Human Services Department reviewed the test results and compared them with standards set by the Texas Commission on Environmental Quality (TCEQ) for Protective Concentration Limits (PCLs) in residential (for Dillo Dirt™) and commercial (for Class B biosolids) soils. Her evaluation accounted for possible exposure through skin, breathing, eating, and drinking for anyone in daily contact with the material.
Ms. Pichette's memo reporting on these test results said "measured concentrations of compounds in these compost and digested sludge samples were below acceptable PCL values and do not pose a risk to human health."