Sensing Heavy Metals Using Mesoporous-Based Optical Chemical Sensors

Table 1

Standards and guidelines for heavy metals in drinking water set by WHO, EPA, and EU legislation [3–5].

Metal	WHO (mg/L)	EPA (mg/L)	EU (mg/L)
Hg	0.006	0.002	0.001
Cu	2	1.3	2
Zn	—	5	—
Pb	0.010	0.015	0.01
Cr	0.05	0.1	0.05