Alteration of Availability of Heavy Metals to Aquatic Microflora by Complexation with Organics Associated with Oil Shale Development

摘要

Oil shale process waters and leachates were examined to determine their propensity to complex with heavy metals and create environmentally harmful soluble toxic substances. Leachates from both raw (unretorted) and Paraho retorted oil shale showed the ability to bind copper, and perhaps cadmium, strongly enough to mitigate the normally inhibitory effects of these metals on the growth of the test alga, Selenastrum capricornutum. The nature of the copper complexation by the oil shale leachate organics suggests the binding of this metal by natural humic and fulvic acids in aquatic systems. The complexation does not appear to be caused by the low-molecular weight ring-N compounds characteristic of retort water. Oil shale leachates are thus only likely to increase copper and cadmium binding and transport significantly in waters whose total organic carbon concentration exceeds that contributed by natural humic and fulvic materials.