0379-3982 0379-3982 S0379-39822018000100035 10.18845/tm.v31i1.3495 Costa Rica Costa Rica Costa Rica 00 03 2018 00 03 2018 31 1 35 46

[1] 2010 1-35 [2 ] WHO 2011 [3] Laboratorio Nacional de Aguas 2014 [4] OMS 2013 Tercera [5] 2002 1-13 [6] 1983 213 71 71 [7] 1987 224-6 [8] 2015 28 3 3 3-14 [9] 2002 44 6 6 541-5 [10] 1996 285-1