Benefits and Issues - Public

Consumers interested in installing CdTe thin-film modules may be concerned about cadmium and its effect on their home environment and the health of their families. The fact is, they have nothing to worry about. Besides being a naturally occurring element, cadmium can be found in many everyday household items that have been proven safe through years of use and research. About 20,000 metric tons of cadmium are used every year to manufacture red and yellow paint, vinyl plastics, television tubes, and the nickel cadmium rechargeable batteries that can be found in cellular phones, power tools, household appliances, and some electric vehicles. CdTe cells are used to power calculators. Cadmium is also present in cigarette smoke. Ten CdTe rooftop modules (1 kW) contain less cadmium than 10 size-C NiCd batteries.

Mercury in fluorescent lights and lead in computer monitors are accepted in households because any health risks are negligible and are outweighed by the benefits of using these metallic elements to improve technology. Although not remotely comparable to mercury or lead, the presence of small amounts of cadmium in sealed PV modules pose virtually no risk to household residents, even in extreme situations such as a house fire. Cadmium compounds cannot be emitted from CdTe PV modules during normal operations or during foreseeable accidents in residential installations.

Although cadmium is pervasive in household products, these products only account for 2.5% of human exposure to cadmium. Most human cadmium exposure comes from ingestion of food because of cadmium uptake by plants from fertilizers, sewage sludge, manure, and atmospheric deposition. Van Assche (1998) has developed a model for cadmium exposure for humans and allocated this exposure to these sources. The assumptions and the data inputs for the model are based on actual data from Belgium and the European Community (ERL, 1990; OECD, 1994). The model estimates of the relative importance of various cadmium sources to human exposure are shown in the following table.