When pickles make the news, good news is the exception (exhibit one: Xi Jinping eats Zhacai).
This week its bad news. According to reports from state run media, century eggs (IPA: pi.tan; Simplified Chinese: 皮蛋; pinyin: pídàn) are processed at many Jiangxi facilities using industrial copper sulphate to expedite the food processing time.
Bottom line? Industrial copper sulphate contains heavy metals. No immediate threat from consumption, but long term consumption will lead to build up of heavy metals in the body.
For English coverage, see this article in the South China Morning Post.