Challenges in the Application of Dendrochemistry in Research on Historical Environmental Pollution in an Old Copper Mining Area

Joanna Dobrzańska,Monika Ziemiańska,Paweł Lochyński,Robert Kalbarczyk

doi:10.3390/f12111505

Abstract

This research investigates the long-term environmental impact and historical temporal pollution patterns caused by a former copper mine in Iwiny (south-western Poland) using a dendrochemical approach. An additional aspect of this research was considering the possibility of using the inductively coupled plasma-optical emission spectrometry (ICP-OES) measurement technique as a cheaper alternative to inductively coupled plasma mass spectrometry (ICP-MS) in dendrochemical analyses conducted in copper mining areas. In the study area, a tailings storage facility (TSF) dam failure (1967) took place and the alkaline flotation waste containing high concentration of Cu and Pb are stored. Tree cores from pedunculate oak (Quercus robur L.) were analysed for the content of 11 trace elements (TEs) (Cd, Mn, Ni, Zn, Cr, Co, Pb, Cu, Fe, Al, Ag) using the ICP-OES technique, while tree rings’ widths (TRWs) were also measured. Samples that were most significant in the context of the research goals were verified with the ICP-MS method. The results revealed the strong long-term impact of the copper industry as reflected in a substantial increase in the mean contents of: (1) Mn, Ni, Zn, Cr, Pb, Cu and Fe in industrial vs. control trees, (2) TRWs for control vs. industrial trees. However, the observed patterns of TEs and TRWs did not correspond to the known timing of pollution inputs (mining activity, tailings spill). Peak levels were observed for Zn and Fe after the mine was closed. The lack of new sources of pollution and the temporal relationship strongly suggests that the tree rings recorded the chemical signal of the TSF reclamation (the use of fertilizers and agrotechnical interventions). Patterns of 7 elements were detected in most of the samples by ICP-OES (Co and Cd were not detected, Al and Ag were partly detected), while ICP-MS detected all of the elements. Significant differences were obtained for Ag, Cd, and Co. Despite challenges with the application of dendrochemistry in research on old mining areas (e.g., lack of old trees), it has proved to be a useful tool for investigating the aggregate environmental impact.

Highlights

The results of this study have provided insight into the long-term impact of copper mining on trees growing in the Old Copper Basin
For Cd and Co, all values obtained were below the limit of detection (LOD), while Ag and Al were detected only in trees growing at the Ind. site
The conducted dendrochemical analyses and tree rings’ widths (TRWs) measurements demonstrated the long-term impact of the copper mining industry on trees in the Old Copper Basin. This was reflected in a substantial increase in mean contents of all trace elements (TEs) in industrial vs. control trees as well as a significantly lower mean TRW of industrial vs. control trees

Summary

Introduction

The accumulation of mine tailings is considered a key problem, because every year billions of tons of waste are generated globally by processing plants [4,5,6]. Studies conducted in areas affected by tailings leakages have focused mainly on the analysis of water [11,12], soil [13], and leaves and fruits [14], because direct monitoring of environmental chemistry often does not cover long periods of time This poses a problem for conducting environmental studies, because mining impact analysis must take into account historical time scales to evaluate the temporal patterns of pollution [5]

Objectives

Methods

Results

Discussion

Conclusion