Assessing the Impact of Removing Select Materials from Coal Mine Overburden, Central Appalachia Region, USA

The exposure of readily soluble components of overburden materials from surface coal mining to air and water results in mineral oxidation and carbonate mineral dissolution, thus increasing coal mine water conductivity. A conductivity benchmark of 300 μS/cm for mine water discharges in the Appalachian region has been suggested to protect aquatic life and the environment. A USGS screening-level leach test was applied to individual strata from three cores collected from a surface mine site in the Central Appalachian region to generate preliminary conductivity rankings, which were used to classify strata for two disposal scenarios: (i) Unmodified Scenario, which included all extracted strata and (ii) Modified Scenario, which excluded 15% (by mass) of the overburden materials with the highest conductivities. We evaluated overburden leaching conductivity using EPA Method 1627 in 18 dry-wet cycles, generating conductivities of 1,020-1,150 μS/cm for the Unmodified Scenario and 624-979 μS/cm for the Modified Scenario. Hence, overburden segregation was successful in reducing the leachate conductivity, but did not reach the proposed benchmark. The leachate was dominated by sulfate in the first four cycles and by bicarbonates in cycles 5-18 in columns with higher sulfur content, while bicarbonates were dominant throughout experiments with lower sulfur content in overburden. The use of conductivity rankings, isolation of potentially problematic overburden strata, and appropriate materials management could reduce conductivity in Central Appalachian streams and other surface mining areas.

Relapsing, bacteremic Klebsiella pneumoniae meningitis in an AIDS patient

The acquired immunodeficiency syndrome (AIDS) is manifested by severe immunologic (predominantly T-lymphocyte) abnormalities and opportunistic infections. Central nervous system (CNS) infections are frequent. Pathogens causing CNS infections in AIDS patients include parasites, fungi, and viruses and are similar to those reported in other states of impaired cell mediated immunity (CMI). A case of relapsing, bacteremic Klebsiella pneumoniae meningitis in an AIDS patient is presented.

Malignant external otitis with optic neuritis

Malignant external otitis (MEO) is a progressive necrotizing infection which spreads to the skull base. The causative organism is usually Pseudomonas aeruginosa and 90% of the patients are diabetic. The infection gains access to the skull base at the temporal bone. Cranial nerve involvement is common. We present a case of malignant external otitis causing blindness due to optic neuritis. Progressive vascular involvement along the skull base is the pathogenic mechanism that best explains spread from the temporal bone to the orbital apex.