Also, real ppm for this kind of thing is supposed to be by weight, so that would ideally be pounds per million-pounds.
IOW if they dumped a million pounds all over the place, and there was 1 ppm of trace lead content, then there was one full pound of unwanted lead scattered across the same acreage as the 900,000+ pounds of active ingredient.
However, ppm for environmental laboratories conventionally means milligrams per liter since that's a close equivalent to weight ppm, but realistically only for water samples. So for test material having a density different than water, some correction is needed which can often be neglected, but the real number is usually within the same order of magnitude.
If there were 280 drops of the DC-10 mentioned in the article, that is a maximum of 280 * 45000 = 12.6M litres of this, spread of 20 square miles.
That is 7.5 kg (16 lbs) of lead.
But what does that tell you? Is that a lot? The EPA warns against soil that is > 400ppm lead, which is a limit almost 1000 times higher than found in this.
It's a lot of raw data, but mainly reveals it's all estimation "all the way down".
Definitely pounds to kilos of heavy metals were dispensed widely which were not there before.
Probably a lot more kilos than people think when you consider all the kinds of heavy metal that's popular today, not only Led ;)
And that's just the initial application.
Contamination migration will be a much less accurately determined phenomenon, while being potentially much more toxic in those areas of concentration, and less so in areas benefitting from dilution.
IOW if they dumped a million pounds all over the place, and there was 1 ppm of trace lead content, then there was one full pound of unwanted lead scattered across the same acreage as the 900,000+ pounds of active ingredient.
However, ppm for environmental laboratories conventionally means milligrams per liter since that's a close equivalent to weight ppm, but realistically only for water samples. So for test material having a density different than water, some correction is needed which can often be neglected, but the real number is usually within the same order of magnitude.