Researchers found that treating PFAS measurements below laboratory reporting limits as ‘zero’ may underestimate how widespread the chemicals are in U.S. drinking water.By Alissa de ChasseyWhen PFAS concentrations in drinking water fall below laboratory reporting limits, they are sometimes treated as ‘zero’ in statistical analyses. But a new study published in Cell Reports Sustainability, which reanalyzed federal monitoring data, found that estimated PFAS concentrations in U.S. drinking water could be more than twice as high as calculations that treat results below laboratory reporting limits as zero suggest.