Caffeine as an anthropogenic marker of domestic waste: A study from Lake Simcoe watershed

The reliability of using caffeine (1,3,7-trimethyl xanthine) as an anthropogenic marker of human mediated contaminants in the inland water system has been studied from the Lake Simcoe watershed in Central Ontario, Canada. Both water and sediment samples were collected on a biweekly interval from five sampling locations for a period of 8 months from May to December 2010. In addition, bacterial indicators of the water quality was monitored by enumerating the total coliform and fecal coliform (Escherichia coli) in the water and sediment samples from these sampling locations. The results showed the occurrence of caffeine in all samples collected throughout the study period indicating the presence of human domestic waste in these locations. The coliforms and caffeine in water were negatively correlated while a positive correlation was obtained between these parameters in sediment samples. The study showed a statistically significant variation in caffeine between the sampling locations over the study period with the maximum value recorded at Site 2, the most anthropogenically disturbed area. The seasonal variation of caffeine concentration showed higher values in summer months compared to others and this corresponded to the increased human activities in this area during this period. To conclude, monitoring of caffeine coupled with the bacterial indicators could help to track the origin of contaminants in the inland water systems.