Drinking Water Toxicity in New York City Reservoir and Tap Water Samples

Abstract

Environmental Toxicology Laboratory (ETL) has conducted a preliminary survey of drinking water toxicity in NYC Reservoirs located in Northern Westchester County as well as tap water samples from residences in four NYC boroughs using the Tetramitus Assay. Considerable sediment was collected on glass fiber filters after filtration of 1 liter samples from reservoirs and 3 liter tap water samples. Whole particle analysis revealed particle toxicity both in the reservoirs and NYC tap water samples. The particle toxicity observed in NYC tap water samples varied on a seasonal basis; high toxicity during the summer and early fall, with a decline to no toxicity during November. Discussion is included which affirms the biological plausibility that the toxicity measurements using the Tetramitus Assay may reflect a risk factor for increased cancer incidence.

Tetramitus Toxicity Survey of Waterbodies in the Croton Watershed

Abstract

The Tetramitus Toxicity Survey of Waterbodies in the Croton Watershed provided accurate monitoring data for both whole water and total concentrated particles. Three unexpected outcomes emerged – the toxicity masking effect of whole sediments on particles between 0 –20µ, variations in particle densities after moderate to heavy rainfall, and decrease in particle toxicity after March 1.

Seven sites sampled on February 18, 2000 displayed neither whole water nor particle toxicity. These observations fixed in time the beginning of the winter “meltdown” and the subsequent run-off of previously unavailable toxic sediment. Test method variability and sample variability was far below other commonly used bio-monitoring tests (EPA battery of whole effluent toxicity tests). Seasonal variations of sediment pollution awaits further study and analysis, for which the Tetramitus Assay is well suited.