Measurement of volatile organic compounds in bottled and tap waters by purge and trap GC–MS: Are drinking water types different?

Volatile organic compounds (VOCs) including major trihalomethanes (THMs) in bottled and tap waters from Central Missouri were quantified and compared with drinking water guidelines. Tap (n = 34), spring (3 brands, n = 25), purified (8 brands, n = 58), distilled (3 brands, n = 12) and flavored waters (5 brands, n = 34) along with Missouri River water (n = 30), were analyzed by purge and trap gas chromatograph–mass spectrometry (GC–MS) using USEPA method 524.2. The mean recoveries of the internal and surrogates standards were fluorobenzene: 100%, benzene d5-, chloro: 100% and 1,4-dichlorobenzene d4: 96%. Approximately 97% of all drinking water types were found to be safe for human consumption. However, two tap water samples recorded bromodichloromethane concentrations above the 60 μg/L World Health Organization (WHO) limit. Moreover, six tap water samples exceeded both the 80 μg/L USEPA Stage I limit and the 100 μg/L European Community (EC) maximum contaminant concentration (MAC) for total THMs (TTHMs) in drinking water. TTHMs in the water types ranged from 0–322 μg/L (tap), 0.1–0.3 μg/L (spring), 0–7.6 μg/L (purified), 0.1–18.1 μg/L (distilled), and 0–5.7 μg/L (flavored). Kruskal–Wallis Chi square approximation showed significant differences (P < 0.001) in the levels of THMs found in the water types. Principal components (PC1 and PC2) with 97% total variance suggested similarities in most drinking waters except for Boonville and Columbia tap waters. Dendrogram plots of TTHMs and Σ VOCs revealed two principal clusters with Columbia and Boonville tap waters in a different cluster and also distant from other water types.