This March, the FASS Environment Research Cluster was pleased to welcome Dr Giuliano Locosselli from the Institute of Biosciences, University of Sao Paulo.
Dr Locosselli studies the impact of environmental change on the development of trees growing in the natural environment. Most of this research use tree rings as a means to evaluate the development of trees in high temporal resolution. Recently, Dr Locosselli began applying tree ring analysis to the complex urban environment. It uses both tree rings and tree bark as biomonitoring tools to reconstruct the spatial/temporal variation in environmental pollution in cities and its effects on citizens’ health. He has applied these approaches in São Paulo, Brazil, and in Lyon, France.
During his short stay in Singapore, Dr Locosselli collected tree ring samples around the NUS Kent Ridge Campus. The samples will be sent for further laboratory analysis to extract data on the pollutants found in the trees here. This preliminary study will help to determine the suitability of trees and tree species in Singapore as biomonitoring indicators. If successful, Singapore may be able to use trees to complement existing studies on lake sediment cores in environmental research.
Dr Locosselli also conducted a workshop titled ‘Principles of Biomonitoring Studies in Cities’, and a seminar titled ‘Trees as Archives of Environmental Quality’ for the Environment Research Cluster. Their abstracts can be found below.
Biomonitoring studies allow one to estimate the levels of environmental pollutants when instrumental data are limited or unavailable. The approach is based on organisms that are actively introduced to the study site or on organisms that are already found in such sites. The latter passive biomonitors include urban trees. Urban trees are key biomonitoring tools that provide information about the spatial and temporal variability of environmental pollutants, including Pb, Al, Zn, Ni, and other metals. The chemical composition of tree bark and tree rings can be analyzed using different methods. X-ray fluorescence (XRF) is one of the methods used for the analysis of the chemical composition of tree bark. Laser ablation coupled with the ICP-MS is a method well-suited for tree-ring studies.
In this class, we will go through key principles behind both analyses, including sample preparation, measurement and analysis. We will discuss the advantages and disadvantages of these approaches.
Air pollution is a growing concern in cities worldwide, causing 4.2 million premature deaths each year. The risk associated with air pollutants, however, is not always clear because long records of air pollution are missing for most cities, and many classes of contaminants such as airborne metals are not routinely monitored. Where present, data from air quality stations may not reflect the full extent of spatial variation in pollution, due to the intrinsic complexity of the urban landscape. Biomonitoring studies can help fill gaps in instrumental data to provide long-run archives of environmental quality with high spatial resolution. Trees are key passive biomonitoring tools found in cities around the world. Dendrochemical analysis of urban trees can reconstruct the temporal variation in environmental pollution. The chemical composition of the tree rings can inform how pollution varied through time, as well as within and across cities. The approach uses recent laser ablation technology coupled with mass spectrometry, assessing the chemical composition of wood at the cellular level and increasing the approach’s precision and reliability. Dendrochemical studies are combined with the analysis of the chemical composition of tree bark in order to evaluate the spatial variability of pollutants. Different chemical elements found in ambient air are passively adsorbed to the porous surface of tree bark. Air quality can be monitored using both approaches, helping policymakers improve public health and well-being in cities.