Targeted and Nontargeted MS Analysis of Contaminants in Storm Water Retention Ponds

Significance of the Topic

Understanding the presence and distribution of trace organic pollutants in storm water retention ponds is crucial for assessing environmental risk, protecting aquatic ecosystems, and ensuring the safety of reclaimed irrigation water. Comprehensive monitoring strategies that integrate non-targeted screening with targeted quantitation can reveal both known and unexpected contaminants, guiding management of water resources in recreational and residential communities.

Objectives and Study Overview

This study demonstrates a two-stage, data-driven workflow for environmental monitoring at a coastal golf course community in Kiawah Island, SC. First, non-targeted high-resolution accurate-mass (HRAM) screening identifies a broad spectrum of organic micropollutants in storm water and wastewater samples. Second, prioritized compounds are quantified using an online solid phase extraction (SPE) coupled to triple quadrupole LC-MS/MS, allowing sub-ppt detection of turf-grass management chemicals and wastewater-derived contaminants across multiple sampling sites.

Methodology

Surface water from connected retention ponds, groundwater wells, and treated municipal wastewater were collected as grab samples over two field campaigns. Non-targeted extracts (0.5 L) were analyzed by HPLC–HRAM MS with data-dependent MS/MS to screen against an environmental database and spectral library. Confirmed targets were quantified in 10 mL samples using online SPE LC-MS/MS under selected-reaction monitoring (SRM) mode.

Instrumentation

• HRAM MS: LTQ Orbitrap Velos with heated electrospray ionization (HESI), full scan m/z 100–1000 at 60,000 resolution
• Software: ExactFinder for feature scoring and library matching; TraceFinder for calibration and QC
• Online SPE LC-MS/MS: EQuan MAX Plus system, Hypersil GOLD aQ trap column, Accucore aQ analytical column
• Triple quadrupole MS: TSQ Quantiva in positive HESI-SRM mode with optimized collision energies and gas settings

Main Results and Discussion

Non-targeted screening detected over a dozen contaminants including fluridone, atrazine, DEET, metoprolol, and sulfamethoxazole. Fluridone identification was confirmed by accurate mass (<0.5 ppm error), isotope pattern matching, and library MS2 scoring (70%). Targeted quantitation achieved detection limits down to 0.06–62.5 ng/L. Boxplots comparing retention ponds and wastewater lagoon revealed elevated turf-grass herbicides in golf course runoff ponds and pharmaceutical residues in wastewater-impacted sites.

Benefits and Practical Applications

• Comprehensive non-target screening simplifies initial pollutant discovery without developing individual methods for each analyte
• Online SPE–MS/MS enables rapid, high-throughput quantitation of trace contaminants at sub-ppt levels
• Combined approach informs water-management decisions for recreational landscapes and reclaimed water reuse

Future Trends and Applications

• Integration of toxicological assays to evaluate ecological impacts of detected micropollutants
• Expansion of spectral libraries to cover emerging contaminants and transformation products
• Application of machine learning for feature prioritization and source apportionment
• Development of automated workflows for real-time environmental surveillance

Conclusion

This work illustrates an efficient, two-tiered analytical strategy that couples HRAM non-target screening with sensitive online SPE LC-MS/MS quantitation to characterize and measure trace organic contaminants in storm water retention systems. The methodology supports informed environmental management and paves the way for broader adoption in water quality monitoring programs.