[Metal content and trace elements in groundwater supply of the island of El Hierro (Canary Islands, Spain).]

Abstract

Objective: Volcanic eruptions are a natural source of substances potentially dangerous to human health. The island of El Hierro (Canary Islands, Spain) suffered a marine volcanic eruption in 2012, making it necessary to monitor the levels of certain elements that can alter the quality of groundwater supply. The objective of this work was to determine the content of metals and trace elements in the groundwater supply of the Isla del Hierro and to check if they met the quality parameters established in Spanish legislation.

Methods: The content of metals and trace elements (aluminum, lead, cadmium, calcium, potassium, sodium, magnesium, boron, barium, cobalt, chromium, copper, iron, lithium, manganese, molybdenum, nickel, strontium, vanadium, zinc, fluorine) in a total of 60 samples of groundwater supply and agriculture from six different sampling points on the island. The determination was carried out by inductively coupled plasma optical emission spectrophotometry (ICP-OES) and by fluoride ion selective potentiometry. The data were statistically analyzed applying the Kolmogorov-Smirnov test, Levene's statistic, Kruskal-Wallis, Mann-Whitney U, ANOVA and Tukey's test. Significant differences were those that met p<0.05.

Results: The highest mean concentration of lead was recorded in the Tigaday samples (0.003±0.0005 mg/L), finding statistically significant differences (p<0.05) in the lead levels between the sampling points. The elements analyzed were below the parametric values set in Royal Decree 140/2003.

Conclusions: The results obtained reflect that, in all the samples analyzed, the quality parameters established in the Spanish legislation (RD 140/2003) are met, being, therefore, waters suitable for human consumption.