Bisphenol A (BPA), the controversial plastics chemical, has returned to the forefront in the packaging industry after links were found to reduced sperm quality by a US study.

Universities of Michigan and Harvard tested, over a month, 190 men and found that those with the highest concentration of BPA had about 23% lower sperm concentration than those with the lowest concentration.

The findings of the study are not good for the plastics industry, as it has  been consistently claimed that the use of BPA in plastics is kept at safe levels that are well below anything that could cause health risks.

Assistant professor at the University of Michigan School of Public Health, John Meeker, led the research.

He said: "Much of the focus for BPA is on the exposures in utero or in early life, which is of course important, but this [research] suggests exposure may also be a concern for adults."

A study of 230 workers in a Chinese factory last year found links between BPA exposure and erectile dysfunction.

The 190 participants in the study gave sperm and urine samples, whilst seventy-eight gave additional urine samples a month apart. In 89% of the urine samples, BPA was detected. 

"We found that if we compare somebody in the top quartile of exposure with the lowest, sperm concentration was on average about 23% lower in men with the highest BPA," said Meeker.

In regards with moving forward with BPA, France and Denmark have recently announced they are to ban the substance, whilst the UK continues to defend its usage.

Plastics and epoxy resins use BPA to in order to make packaging and other products.