Long term performance of an AMD treatment bioreactor using chemolithoautotrophic sulfate reduction and ferrous iron precipitation under in situ groundwater conditions.

Chemolithoautotrophic sulfate reduction (CSR) was tested to treat natural acid mine drainage influenced groundwaters. The long term behavior was studied for more than 3 years under groundwater conditions (10 °C, autochthonous sulfate reducing bacteria (SRB)) without biomass replenishment in a 190 L bench scale reactor. The process produces water with alkalinity >10 mM. pH can be controlled by p(CO(2)) for all expectable water qualities. SRB were immobilized using an expanded clay bed. After 1.3 years of operation, a constant biomass content and sulfate reduction rate of 0.25-0.30 mmol(so)4(Lh)⁻¹ were established. The sulfate reduction rate was limited by biomass content. Most of the electrons were used for sulfate reduction (98%). The hydrogen turn over in competing processes like methanogenesis and homoacetogenesis was successfully suppressed by adjusting the sulfate concentration to be >2 mM in the runoff.

Response to thoracic radiotherapy in patients with small cell carcinoma of the lung after failure of combination chemotherapy.

Chest radiotherapy was given to 23 patients with small cell carcinoma of the lung after development of progressive intrathoracic tumor on chemotherapeutic regimens. Treatment schedules were variable, with a median dose of 3,200 rad (32 Gy) in 10 fractions. Objective tumor regression within the radiation portal was observed in 12 patients (52%). Only 3/12 responders did not develop clinically detectable local tumor recurrence before death. Actuarial median time to local tumor progression was 2.5 months in responding and 3.5 months in nonresponding patients. Relapse of intrathoracic small cell carcinoma despite combination chemotherapy was not effectively treated by chest irradiation in the doses utilized. If sustained local palliation is required in this population, higher doses of radiation should be considered.