title: Impact of nickel mining in New Caledonia assessed by compositional data analysis of lichens.
abstract: The aim of this study is to explore the use of lichens as biomonitors of the impact of nickel mining and ore treatment on the atmosphere in the New Caledonian archipelago (South Pacific Ocean); both activities emitting also Co, Cr and possibly Fe. Metal contents were analysed in thirty-four epiphytic lichens, collected in the vicinity of the potential sources, and in places free from known historical mining. The highest Ni, Co, and Cr concentrations were, as expected, observed in lichens collected near ore deposits or treatment areas. The elemental composition in the lichens was explored by multivariate analysis, after appropriately transforming the variables (i.e. using compositional data analysis). The sample score of the first principal component (PC1) makes the largest (positive) multiplicative contribution to the log-ratios of metals originating from mining activities (Ni, Cr, Co) divided by Ti. The PC1 scores are used here as a surrogate of pollution levels related to mining and metallurgical activity. They can be viewed as synthetic indicators mapped to provide valuable information for the management and protection of ecosystems or, as a first step, to select locations where air filtration units could be installed, in the future, for air quality monitoring. However, as this approach drastically simplifies the problem, supplying a broadly efficient picture but little detail, recognizing the different sources of contamination may be difficult, more particularly when their chemical differences are subtle. It conveys only relative information: about ratios, not levels, and is therefore recommended as a preliminary step, in combination with close examination of raw concentration levels of lichens. Further validation using conventional air-monitoring by filter units should also prove beneficial.
authors.affiliation: Pôle Pluridisciplinaire de la Matière et de l'Environnement, Université de la Nouvelle-Calédonie, BP R4, Nouvelle-Calédonie, 98851 Nouméa Cedex, France.
authors.forename: Camille
authors.identifier: 0000-0002-9638-5405
authors.initials: C
authors.lastname: Pasquet
authors.affiliation: UMR 6298, ArTeHis, Université de Bourgogne-Franche Comté, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon, France.
authors.forename: Pauline
authors.initials: P
authors.lastname: Le Monier
authors.affiliation: UMR 6298, ArTeHis, Université de Bourgogne-Franche Comté, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Monna
authors.affiliation: UMR 6282, Biogéosciences, Université de Bourgogne-Franche Comté, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Durlet
authors.affiliation: UMR-CNRS 8148, Géosciences Paris-Sud, Université Paris-Sud, Bât. 504, 91405 Orsay Cedex, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Brigaud
authors.affiliation: UMR CNRS 7154, Institut de Physique du Globe de Paris (IPGP), Sorbonne Paris Cité, Université Paris Diderot, 1 rue Jussieu, 75013 Paris, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Losno
authors.affiliation: UFR SVTE, Université de Bourgogne-Franche Comté, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon, France.
authors.forename: Carmela
authors.initials: C
authors.lastname: Chateau
authors.affiliation: Pôle Pluridisciplinaire de la Matière et de l'Environnement, Université de la Nouvelle-Calédonie, BP R4, Nouvelle-Calédonie, 98851 Nouméa Cedex, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Laporte-Magoni
authors.affiliation: Pôle Pluridisciplinaire de la Matière et de l'Environnement, Université de la Nouvelle-Calédonie, BP R4, Nouvelle-Calédonie, 98851 Nouméa Cedex, France.
authors.forename: Peggy
authors.initials: P
authors.lastname: Gunkel-Grillon
keywords: Biomonotor; Trace metal; Ultramafic rock