Potential toxicity of improperly discarded exhausted photovoltaic cells.

Low tech photovoltaic panels (PVPs) installed in the early '80s are now coming to the end of their life cycle and this raises the problem of their proper disposal. As panels contain potentially toxic elements, unconventional, complex and costly procedures are required to avoid environmental health risks and in countries where environmental awareness and economic resources are limited this may be especially problematic. This work was designed to investigate potential risks from improper disposal of these panels. To accomplish this aim an exhausted panel was broken into pieces and these were placed in water for 30 days. The resulting leached solution was analyzed to determine chemical release or used in toto, to determine its potential toxicity in established tests. The end points were seed germination (on Cucumis sativus and Lens culinaris) and effects on early development in three larval models: two crustaceans, Daphnia magna and Artemia salina, and the sea urchin Paracentrotus lividus. Our results show that the panels release small amounts of electrolytes (Na, Ca and Mg) into solution, along with antimony and manganese, with a concentration under the accepted maximum contaminant level, and nickel at a potentially toxic concentration. Developmental defects are seen in the plant and animal test organisms after experimental exposure to the whole solution leached from the broken panel. The toxic effects revealed in in vitro tests are sufficient to attract attention considering that they are exerted on both plants and aquatic animals and that the number of old PVPs in disposal sites will be very high.

Chronic cerebellar stimulation for cerebral palsy: a double-blind study.

A double-blind, crossover technique was devised to assess the value of chronic cerebellar stimulation in children with cerebral palsy. Cerebellar stimulators were implanted in eight children and adolescents with cerebral palsy. The external transmitter was changed monthly during each of the first 3 months and was set to be functional or placebo by random assignment. Objective assessment by physical, occupational, and speech therapists as well as by a neurologist failed to document significant improvement in any of the participants. Some children became less spastic and developed increased mental alertness and improved clarity of speech. However, these improvements occurred during placebo periods as often as with stimulation.