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. Author manuscript; available in PMC: 2022 Apr 25.
Published in final edited form as: Lancet Planet Health. 2022 Apr;6(4):e320–e330. doi: 10.1016/S2542-5196(22)00043-2

Figure 2: Dendrogram of hierarchical cluster analysis for 6-year averages (2006–11) of regulated metal concentrations in CWSs across the USA (n=12 756).

Figure 2:

Analysis was restricted to CWSs with no missing concentration estimates for arsenic, selenium, uranium, barium, and chromium. Values for uranium are averaged from 2000–11. We used Ward’s method for Euclidean distances and normalised each metal to unit variance and zero mean before analysis. CWS=community water system.