Contamination of wild-grown edible mushrooms by heavy metals in a former mercury-mining area

Abstract

The aim of this study was to evaluate the contamination of six edible wild species of mushrooms (Boletus pulverulentus, Cantharellus cibarius, Lactarius quietus, Macrolepiota procera, Russula xerampelina and Suillus grevillei) by heavy metals (Hg, Cd, Pb, Zn, Cu, Ni, Cr, Co, Mn and Fe). Mushroom samples were collected from sites contaminated by emissions from mining and processing of polymetallic ores in operation during the period 1969–1993 in Rudňany, southeast Slovakia. The four study sites spanned up to a 5-km distance from the emission source. The collected mushroom samples were analyzed using Flame Atomic Absorption Spectrophotometry and/or Flame Atomic Absorption Spectrophotometry with graphite furnace. Mercury, Cd and, in some samples, also Pb present the highest risks in terms of contamination of the food chain following subsequent consumption. The content of two metals in the dry matter (dm) of the mushrooms exceeded the limits set by the European Union (EU; Cd: 0.5 mg/kg dm, Pb: 1.0 mg/kg dm). The highest mean contents of the eight metals recorded for S. grevillei were 52.2, 2.15, 107, 104, 2.27, 2.49, 81.6 and 434 mg/kg dm for Hg, Pb, Zn, Cu, Ni, Cr, Mn and Fe, respectively. The highest content of Cd was recorded in M. procera (3.05 mg/kg dm) and that of Co in L. quietus (0.90 mg/kg dm). The calculated weekly intake for Hg, Pb and Cd shows that regular consumption of mushrooms from the studied area poses risks to human health.

Keywords:

• Wild edible mushrooms
• heavy metals
• contamination
• mercury smelter

Acknowledgment

The authors thank Dr. Shubhadeep Roychoudhury for his critical comments and language corrections.

Additional information

Funding

This study was financially supported by the Ministry of Education of the Slovak Republic project VEGA 1/0724/12 “Determination of point, diffusive and soil profile mercury contamination of production areas in the Middle Spiš region, northern Gemer and possibilities to minimize Hg inputs into plant products” and the project on “Development of International Cooperation for the Purpose of the Transfer and Implementation of Research and Development in Education Programs” conducted by the Operational Programme: Education, ITMS code: 26,110,230,085.