An example balloon system for long-duration flight can include an optically transparent envelope for solar greenhouse heating of lift gas within, a fuel cell inside a bladder within the envelope, and a solar collector beneath the bladder configured to concentrate solar energy in a focal region below the bladder. The detecting and indicating circuits may be carried in whole or in part by one of or both of the needle andor the vascular access port. When used together, the componentsreduce emissions of elemental and oxidized mercury;increase the level of Hg, As, Pb, andor Cl in the coal ash;decrease the levels of leachable heavy metals in the ash, preferably to levels below the detectable limits; andmake a highly cementitious ash product. The plate has a sleeve to accept the leg.