Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Determination of Metals and Metalloids in Marine Sediments. Evaluation of the Contamination Levels in Tenerife Island

Abstract

Metals and metalloids are usually bound in the fine-grained (<63 µm) fraction of the marine sediments, due to the high surface area and humus content. In this fraction, the metals have a greater biological availability than in the coarser fractions. In the present work, the content of total metals and metalloids, their distribution and accumulation in marine sediments collected in the Tenerife Island (Spain) was evaluated. Thirty-six samples collected near the nine points of discharge located along the entire coast were analyzed. The concentration of 47 elements was determined by microwave-assisted digestion followed by Inductively Coupled Plasma Mass Spectrometry (MAE-ICP-MS) analysis. Important levels of contamination from a high number of elements were found in samples, the concentrations of Pb was higher than the ecotoxicological assessment criteria (EAC) established by the OSPAR (5 mg kg⁻¹) in some cases. Principal component and correlation analysis were developed and the results obtained indicated that there are two principal sources of anthropogenic pollution, with a large number of elements related to them. The amounts of 13 elements found in the sediments of the sampling point of Santa Cruz of Tenerife, principal city of the island, were higher than those found in the other locations. Modifications in the sea bed were also detected due to industrial wastes; concentrations of metals related to metallurgic activities have increased in the industrial area while the proportion of original igneous sediments decreased. The mobility of the pollutants, according to the sea currents, was also evaluated. For some of the analyzed metals, differences between sampling points in agreement with the direction of the marine currents in the area were obtained. The large number of elements analyzed allowed the development of a geochemical characterization of the three slopes of the island. Significant differences were observed for some elements.

Keywords:

• ICP-MS
• Metal pollution
• Principal component analysis
• Sediment pollution
• Urban pollution

Acknowledgments

The present work was supported and funded by the Ministry of Education Culture and Sports of Spain (Project No. CTQ2011-24210/PPQ). The authors are grateful to Certio Environment S.L. and Air Liquide España S.A., for its valuable contribution to this study.

Notes

^a Population (year 2010).

^b n/a: no available. Since this point is an industrial area, there is no population related to it.

^a Limit of Quantitation.

^c Relative Standard Deviation.