Aluminum is among the most common elements found in the Earth’s crust. Soil eroded by flowing water invariably discharges aluminum. For surface coal mining, this represents an engineering and technical challenge because rainfall and snow melt must be collected and channeled into ponds for sediment to settle before the water is discharged to a stream. On every particle of discharged sediment potentially clings a molecule of aluminum. Because the discharge is controlled by an NPDES permit which customarily limits the number of parts per million of aluminum in the water, excessive aluminum results in a permit violation and potentially monetary penalties or other enforcement against the coal operator.
A recent article by WVU researchers Y. Thomas He and Paul Ziemkkiewicz, in the publication Chemosphere reveals that USEPA has excessively regulated the discharge of aluminum by over-estimating its availability. Aluminum in a dissolved state is injurious to aquatic life. This is well known and not seriously disputed. Aluminum, however, rarely exists in a dissolved state and instead is measured and reported in a “total” form, meaning that it is measured with those molecules clinging to particles of sediment, normally clay. To measure its presence, USEPA has long designated Method 200.7 to determine total recoverable aluminum. According to He and Ziemkkiewicz, “USEPA argues that its method 200.7 digestion results in minimal aluminosilicate clay dissolution and releases meta-stable metal forms that may exit the treatment system as solids or attached to solids but release upon exposure to possibly acidic conditions in the receiving stream.” Under the experiment reported, USEPA Method 200.7 “releases signiﬁcant Al from the clay structure. Our results indicate that, as a result, it signiﬁcantly over-estimates total recoverable aluminum and, thus, overestimates the amount of Al that might be released under realistic, ﬁeld conditions.”
But wait; there’s more. Not only does USEPA’s test method force the release of aluminum from the sediment to which it is attached, it grossly exaggerates the conditions under which the aluminum will enter a dissolved state in acidic conditions. He and Ziemkkiewicz report that “after 10 days of reaction in strongly acidic solution (pH 2.5), the determined, dissolved Al concentration is much lower than total recoverable aluminum extracted by USEPA method 200.7. In less acidic stream conditions, the release of Al is much less signiﬁcant. [E]ven with a signiﬁcant amount of total suspended solids, Al concentration is expected to be at background level at pH 5.5.”
These conclusions are not a matter of mere academic interest. Millions of dollars have been spent by the mining industry to control the discharge of aluminum. Millions more have been spent in civil penalties or defense of enforcement actions brought by agencies and citizens. The Ziemkkiewicz research strongly suggests that USEPA has employed a test method so flawed that it has created an environmental problem which may not exist.
So much for “world class” science that USEPA has touted for the last seven years.
This article was authored by Blair M. Gardner, Jackson Kelly, PLLC.