In the 1980's billions of batteries were thrown into landfills. There is growing concern that as the batteries deteriorate, the toxic metals they contain will seep into the groundwater and contaminate it. That concern is unfounded, however, for studies of groundwater near large landfills used in the 1950's and then closed showed little, if any, such contamination.

Which of the following, if true, most seriously weakens the argument above?

(A) Compared to typical 1980's landfills, typical 1950's landfills contain a negligible number of batteries.
(B) In the 1950's batteries contained higher amounts of toxic metals than they did in the 1980's.
(C) In the 1950's incinerator ash dumped in landfills contained more toxic material from batteries than did such ash in the 1980's.
(D) Batteries manufactured in the 1980's were less likely to leak fluids containing toxic metals than were 1950's batteries.
(E) In the 1980's efforts to recycle the toxic metals contained in batteries increased substantially.