Sounding the Alarm on Water Quality: Predictive Modeling of Total Trihalomethanes Using Chlorine Residuals

Flint water crisis in Michigan caused pathological fatalities traced to contamination of lead and Legionella bacteria in aging pipes. Elsewhere in Georgia, domestic Marietta waters registered abnormal carcinogen levels, including total trihalomethanes (TTHM, also detected in Flint crisis), due to chlorine disinfection which interacts with natural organic matter and forms TTHM. Further, industrial pollutants disrupt water chemistry by metal leaching and generating ammonia – making periodic testing an unmet public health responsibility. This study tests domestic Marietta waters for pH, lead, and chloride derivatives, hypothesizing that waters from metal versus polyvinyl chloride (PVC) plumbing will have high chloride derivatives and therefore, high levels of TTHM. Waters from homes aging 0-30 years or over 35 years, and mineral water controls were analyzed using TESPERT drinking water test kit. High-chlorine samples were tested for TTHM by gas chromatography/mass spectrometry (Paragon labs, Livonia, MI). Irrespective of year built, ~50% of homes had PVC/copper plumbing. Compared to PVC pipes, metal plumbing showed acidic waters (pH: 5-6.4) with higher levels of total and free chlorine (~1ppm) and demonstrating a trend that positively correlates with higher TTHM levels (10-30ppb) – predominantly chloroform and bromodichloromethane. Bromine was highest in waters from polybutylene (3ppm) and lead (1.5ppm) plumbing. Overall, these findings warrant free chlorine levels as an indicator of the presence of carcinogenic TTHM constituents and warrant preventive measures of boiling and stringent filtration, with periodic seasonal testing of chloride derivatives to monitor alteration patterns.