Ζ potential evidences silanol heterogeneity induced by metal contaminants at the quartz surface: Implications in membrane damage.

•Pure and metal-contaminated quartz differs in silanol acidity and heterogeneity.•Quartz surface heterogeneity is described by means of ζ potential titration curves.•Silanol heterogeneity parallels quartz membranolytic activity.•The findings support silanol heterogeneity as cause of crystalline silica toxicity.