I wonder if the question is, what is not in the water?
Higher Lithium levels in water correlate not only with reduced suicide rate (well-known), but with reduced violent crime.
Although suicide is considered a major preventable cause of mortality worldwide, we do not have effective strategies to prevent it. Lithium has been consiste...
www.frontiersin.org
In pharmacological doses, lithium successfully treats bipolar disorder and it can reduce violent crimes committed by individuals with this disorder. To investigate whether naturally occurring lithium in drinking water lowers rates of violent crime ...
www.ncbi.nlm.nih.gov
Of course, not necessarily Litium.
These ingredients were high in NYC water in 2011
Contaminants in NYC drinking water raise alarms about public health and environmental safety.
www.businessinsider.com
I don't think that everyone responds to it the same way, but if people are genetically predisposed to violence and live all their lives in the same area, I think it is important to check what is, or is not, present in that water and soil.