cosmodyseeus wrote:So I'm assuming the soil is contaminated rather heavily with whatever the groundwater is contaminated with.....
Not necessarily. Groundwater can pick up additional contaminants that are not yet significantly present at any particular soil site, such as late-arriving cyanide plumes. And gardens are known to reflect the effects of episodic air pollution which due to latency and distribution patterns may not have yet entered the groundwater. In some cases soil sites can have significantly high concentrations of insoluble contaminants which are not necessarily present in high concentrations in groundwater since the "napas" may serve as ineffective transport mechanisms.


