Document Type

Master's Culminating Experience

Publication Date



Background: The Celina Water Department treats and supplies surface water contaminated by cyanotoxins from Grand Lake Saint Marys (GLSM) to approximately 12,000 customers in Celina, Ohio. Cyanotoxins are a biochemically and bioactively diverse group of extremely potent natural toxins in water. A common cyanotoxin called microcystin-LR found in GLSM has been associated with acute liver damage and potentially liver and colorectal cancer.

Methods: In this observational study, the city of Celina (Mercer County) Ohio that had a contaminated surface water supply, the cancer incidence was compared with two control cities, St. Marys, and Wapakoneta (Auglaize County) in Ohio, both served by ground water. Cases were identified through the Ohio Cancer Incidence Surveillance System (OCISS) registry from1996-2008. Cumulative age adjusted incidence rates (IRs) for hepatocellular carcinoma (HCC) and colorectal cancer (CRC) were calculated. The cumulative IR, and 95% confidence interval (95% CI) of CRC and HCC were also compared with the IR in Ohio and the Surveillance, Epidemiology and End Results database.

Results: Celina had the lowest cumulative IR of HCC 2.4/100,000 compared to Wapakoneta 5.3/100,000 and Saint Marys 4.0/100,000 people. The IR for HCC was not significantly different than the Ohio or SEER rates (P> 0.05). CRC rates in Celina were 78.4/100,000 which was lower than Wapakoneta 82.9/100,000. However, the CRC IR and 95% CI were significantly higher (P< 0.05) for all 3 cities when compared to either Ohio or national SEER rates.

Conclusion: There is inconclusive evidence to support that cyanotoxins from GLSM are associated with excess risk of cancer from drinking water.