France, Aug. 11 -- French investigators have uncovered microplastic contamination in two of Nestle's top mineral water brands, sparking a renewed legal battle and fresh calls for tougher environmental regulation.

France's bottled-water controversy has resurfaced, with new findings linking "exorbitant" levels of microplastic pollution to long-standing illegal waste dumps operated by Nestle Waters.

According to a joint investigation by the French Office for Biodiversity (OFB) and the Central Office for the Fight against Environmental and Public Health Offences (Oclaesp), water from Nestle's Contrex and Hepar brands contains microplastic concentrations so extreme that scientists say they shatter environmental baselines.

The findings, reve...