Environmental Science: Processes & Impacts blog

Novel spectroscopic techniques could provide a useful tool for monitoring the physiological status of vegetation in post-mining sites, according to a new study by Zuzana et al from the Charles University in Prague, which featured as our Cover Article in Issue 11.

Long-term lignite mining has caused widespread ecological damage in many areas across the world. The principal cause of these problems is acid mine drainage, which causes increased acidity of soil and water environments and subsequent  mobilization of heavy metals e.g. Cd, Zn, Co, Cu and Ni leading to plant uptake from contaminated soils.

Reforestation is a common method for reclamation of post-mining sites with Scots pine being a popular option due to its high ecological tolerance to diverse environments. Monitoring the effects of low pH conditions and heavy metal contamination and identifying key non-specific indicators of stress in this vegetation is therefore important in order to best develop the most effective remediation strategies for post-mining locations.

However, only a limited amount of work has so far been performed under field conditions to establish the effects of high acidity and heavy metal levels on the biochemical processes within vegetation and suitable biomarkers for these effects have not yet been identified. In this study, Zuzana et al. outline the results of a pilot study for monitoring reclaimed post-mining sites, developing a method to identify the key physiological stress factors in Scots pine trees.

Spectroscopic methods are becoming increasingly popular in environmental monitoring. They potentially offer a cheaper and faster alternative to conventional biochemical analysis. The approach in this study modelled the relationship between the visible to-near-infrared (VNIR) spectral properties of Scots pine needles and their key physiochemical properties, measured in the laboratory.

The most suitable biochemical traits identified as non-specific stress indicators for Scots pine trees were ; relative water content (fraction of weight decrease after drying),  content of photosynthetic pigments (chlorophyll a+b and carotenoids, and the ratio of these two components) and concentration soluble phenolic compounds.

The technique was applied to four sites in northwest Czech Republic, each exhibiting different levels of physiological stress. The method was able to successfully separate the different sites, using at least three of the above variables, based on their spectral reflectance data and validated using bootstrapped partial least squares regression (PLSR) modelling  predictions.

The study demonstrates the potential use for the VNIR spectroscopic technique for estimating the physiological status of vegetation in post-mining sites. The method has potential use in larger-scale monitoring studies, allowing simple and quick assessment of reclamation quality in post-mining regions using air-born or satellite hyperspectral data.

This paper is an Environmental Science: Processes & Impacts HOT article and is of interest to researchers interested in contaminated land remediation, specifically post-mining sites, or anyone that likes trees.

Detection of multiple stresses in Scots pine growing at post-mining sites using visible to near-infrared spectroscopy, Lhotáková Zuzana et al, DOI: 10.1039/c3em00388d

Aluminium is the most abundant metal in the Earth’s crust. Its range of desirable chemical and physical properties (e.g. low density, thermal conductivity, corrosion resistance etc) has made it the most widely used metal of the 21^st century, utilised in a huge variety of products and applications, from kitchen utensils to aircraft parts, from food packaging to window frames. However, while the extracting and casting of this abundant resource yields many benefits, the disruption of natural geochemical and biochemical systems may expose organisms including humans to potential harm. It is of paramount importance that we fully understand the ways in which humans are exposed to aluminium and its behaviour within the body. This will allow the nature and extent of potential toxic effects to be assessed and enable people to live safely with these possible dangers.

In this article, which featured on the cover of Environmental Science: Processes & Impacts Issue 10, Christopher Exley provides a detailed and comprehensive critical review, addressing these issues. A broad range of specific aspects within the field of aluminium exposure are covered. The myriad ways in which humans are exposed to aluminium (including inhalation, diet and cosmetics) are discussed as well as the key impact routes (e.g. skin. nose, lung and gut), distribution networks within the body (e.g. blood) and excretion routes. The mechanisms through which aluminium can exert biochemical effects in humans (e.g. pro-oxidant activity, immunopotency and mutagenicity) are also described. Additionally, the article provides a complete and clear description of the aluminium ‘body burden’ (the balance between exposure and excretion).

This article challenges the current perception that aluminium is completely ‘safe’ and demonstrates the need to change our thinking regarding human exposure to metals like aluminium. Furthermore, several key knowledge gaps in this field are identified. Specific areas for future research, required to improve our understanding of aluminium exposure and toxicology, are outlined. In particular, the need to identify specific ‘targets’ within biological systems that may be more vulnerable to aluminium ‘attack’ than others is emphasised. Also, a need to establish an acceptable level of ‘safe’ exposure in humans is highlighted.

Exley suggests that gaining a full understanding of aluminium exposure and body burden in humans will require further data to be gathered from both laboratory and computer modelling approaches. This article will therefore be a valuable resource for researchers within these fields as well as for policy-makers at local and national levels.

Read the full article here:
Human exposure to aluminium, Christopher Exley, DOI : 10.1039/c3em00374d