Characterization of atmospheric emission sources in lichen from metal and organic contaminant patterns

Evaluation of the atmospheric pollution by pesticides using lichens as biomonitors

The extensive use of pesticides combined with their persistence in the environment requires new methodologies to assess more effectively the population exposure to pesticides via air pollution. Biomonitoring pesticides with lichens has been poorly documented, although it represents a complementary approach to the usual active samplings, with an exposure to pesticides accumulated and integrated over several months. An optimized extraction procedure from the lichen Xanthoria parietina followed by a gas chromatographic-tandem mass spectrometric analysis is proposed here to quantify simultaneously 48 pesticides considered in France as priority active substances to monitor in the air. This method has been applied to lichen samples collected in 24 sites in southern France covering urban, industrial, and agricultural areas in order to identify potential contrasts related to anthropogenic activities. Fifteen pesticides (six fungicides, five insecticides, and four herbicides), including four active compounds currently banned by EU legislation, were detected in at least one site. Lindane, diflufenican, difenoconazole, and boscalid were the most common pesticides found in all sites. Urban sites appeared generally less contaminated compared to industrial and rural ones, but a strong heterogeneity was noticed between locations. The biomonitoring with lichens revealed unexpected contaminated areas, partly due to the use of herbicides for vegetation control in industrial and railway installations. The spatial distribution also suggests an input of pesticides by atmospheric transport at the local and regional scales.

Pollution gradient leads to local adaptation and small-scale spatial variability of communities and functions in an urban marine environment

Urbanization of coastal habitats, of which harbors and marinas are the paragon, has led to various ecological paradigms about their functioning. Harbor infrastructures offer new hard substrata that are colonized by a wide variety of organisms (biofouling) including many introduced species. These structures also modify hydrodynamism and contaminant dispersal, leading to strong disturbance gradients within them. Differences in sessile community structure have previously been correlated to these gradients at small spatial scale (<100 m). Local adaptation might be involved to explain such results, but as correlation is not causation, the present study aims to understand the causal link between the environmental gradients and community structure through a reciprocal transplant experiment among three sites of a marina (inner, middle, entrance). Our results highlighted strong small-scale spatial variations of contaminants (trace metals, PCB, pesticides, and PAH) in sediments and animal samples which have been causally linked to changes in community composition after transplant. But historical contingency and colonization succession also play an important role. Our results provided strong evidence for local adaptation since community structure, respiration, and pollutant uptake in Bugula neritina, as well as the metabolomes of B. neritina and Ciona intestinalis were impacted by the transplant with a disadvantage for individuals transplanted from the entrance to the inner location. The here observed results may thus indicate that the disturbance gradient in marinas might constitute a staple for selecting pollutant-resistant species and populations, causing local adaptation. This highlights the importance of conducting further studies into small scale local adaptation.

Influence of environmental and dietary exposures on metals accumulation among the residents of a major industrial harbour (Fos-sur-Mer, France)

OBJECTIVES

We sought to determine whether the residents living closer to the core industrial zone (Fos-sur-Mer) had higher trace metals blood and urinary levels than residents who lived further away (Saint-Martin-de-Crau).

MATERIALS AND METHODS

As part of The INDEX study, we measured the following trace metals into blood and urine samples of 138 participants (80 in the core industrial zone and 58 in the reference area): Antimony, Arsenic, Cadmium, Chromium, Cobalt, Mercury, Nickel, Lead and Vanadium. Participants were recruited using a stratified random sampling method and had to meet the following inclusion criteria: 30-65 years old, living in the area since at least 3 years, not working in the industrial sector, non-smoker. We used single-pollutant multivariate linear regression models, using substitution when censored data were under 15 % and Tobit models alternatively, adjusting for personal physiological, social, dietary, housing characteristics and leisure activities. We also measured these trace metals in samples of lichens (Xanthoria parietina) and atmospheric particles (PM_2.5).

RESULTS

We showed higher lichen and air levels of several metals (Cd, Cr, Co, Ni and Pb) in the exposed area. Living close to the core industrial zone was significantly associated with an increase in blood levels of lead (adjusted geometric mean = 17.2 [15.8-18.7] vs 15.1 [13.7-16.7] µg.L^-1, p < 0.05). We report significant increase of some metals urinary levels among residents of the industrial port zone, as the result of the use of the environment, itself contaminated by industrial activities: dietary history of self-consumption of vegetables (Cadmium), eggs and poultries (Vanadium). However, Vanadium levels were greater among self-consumers of poultry in the reference area and gardeners had circulatory levels of Lead greater than non-gardeners only in the reference area. Consumption of non-local sea-products increased the level of Cadmium.

CONCLUSIONS

These results brought interesting clues, in complement to national programs, regarding the exposure to trace metals of residents living in a major industrial harbor.

Biomonitoring Potentially Toxic Elements (PTEs) Using Lichen Transplant Usnea misaminensis: A Case Study from Malaysia

Urban air pollution has been a major concern due to its impact on global public health. Various techniques for monitoring urban air quality have been developed. However, there is currently a dearth of research on how effective bioaccumulators such as lichen are at monitoring urban air pollution. As a result, the purpose of this research is to investigate the use of U. misaminensis as a biological indicator for biomonitoring urban air quality in Malaysia. Three months were spent exposing lichen samples in three Malaysian cities (Kuala Lumpur, Penang, and Johor Bahru). The trace element content and vitality of the lichens were assessed. The results of this study revealed that U. misaminensis is an effective biological indicator for measuring 25 elements of air pollutants in metropolitan areas. They also revealed that all 25 elements accumulated in the urban area sample were greater than in the control sample. The vitality rate of lichens dropped in the urban area sample when compared with the control sample, indicating that an increase in elements in the air will impact the vitality rate of any biological component. In this study, two arguments are made: (a) Lichen is an excellent biological indicator, particularly for urban air pollutants such as potentially toxic elements; and (b) traffic is the primary contributor to urban air pollution; hence, the local government requires a better plan and design for urban areas to decrease air pollutants build-up.

Using Bayesian networks for environmental health risk assessment

The study investigated the potential relationships between air pollution, socio-economy, and proven pathologies (e.g., respiratory, cardiovascular) within an industrial area in Southern France (Etang de Berre), gathering steel industries, oil refineries, shipping, road traffic and experiencing a Mediterranean climate. A total of 178 variables were simultaneously integrated within a Bayesian model at intra-urban scale. Various unsupervised and supervised algorithms (maximum spanning tree, tree-augmented naive classifier) as well as sensitivity analyses were used to better understand the links between all variables, and highlighted correlations between population exposure to air pollutants and some pathologies. Adverse health effects (bronchus and lung cancers for 15-65 years old people) were observed for hydrofluoric acid at low background concentration (<0.003 μg m^-3) while exposure to particulate cadmium (0.210-0.250 μg m^-3) disrupts insulin metabolism for people over 65 years-old leading to diabetes. Bronchus and lung cancers for people over 65 years-old occurred at low background SO₂ concentration (6 μg m^-3) below European limit values. When benzo[k]fluoranthene exceeded 0.672 μg m^-3, we observed a high number of hospital admissions for respiratory diseases for 15-65 years-old people. The study also revealed the important influence of socio-economy (e.g., single-parent family, people with no qualification at 15 years-old) on pathologies (e.g., cardiovascular diseases). Finally, a diffuse polychlorinated biphenyl (PCB) pollution was observed in the study area and can potentially cause lung cancers.

Concentrations and transportation of metal and organochlorine pollutants in vegetables and risk assessment of human exposure in rural, urban and industrial environments (Bouches-du-Rhône, France)

The bioaccumulation of metals (As, Cd, Co, Cr, Cu, Ni, Pb, Sb, V, Zn, Al, Fe) and organochlorine compounds (PCDD-Fs and PCBs) was assessed in soils and vegetables of 3 sites of contrasted anthropogenic influence (rural and industrial-urban areas). Cultivated soils in industrial areas exhibited diffuse pollution in organochlorine pollutants (PCBs and PCDD-Fs). The pollutant levels encountered in vegetables were always lower than the EU regulatory or recommended values. However, the contents measured in vegetables cultivated near industrialized areas were significantly higher than those observed in rural areas. This was notably the case for Co, Cd, Cr, Ni, Pb, V, NDL- and DL-PCB, PCDD, and PCDF. The leaf pathway appeared as the main absorption pathway for many contaminants. The results suggested that population exposure to pollutants was mainly caused by vegetable ingestion. In the vegetables and soils, the toxicity was mainly caused by the V, Co, Cd, and Pb contents to which can be added As and PCDD-Fs for soils. Therefore, the proximity of vegetable crops to highly anthropised areas has led to long-term exposure of vegetables and soils to air pollutants, leading to an accumulation in the food chain and thus a risk for human health.

Effects of meteorological conditions and topography on the bioaccumulation of PAHs and metal elements by native lichen (Xanthoria parietina)

The bioaccumulation of PAHs and metal elements in the indigenous lichens Xanthoria parietina was monitored during two years at a quarterly frequency, in 3 sites of contrasted anthropic influence. The impact of the meteorological factors (temperature, relative humidity, rainfall, wind speed) was first estimated through principal component analysis, and then by stepwise multilinear regressions to include wind directions. The pollutants levels reflected the proximity of atmospheric emissions, in particular from a large industrial harbor. High humidity and mild temperatures, and in a lower extent low wind speed and rainfall, also favored higher concentration levels. The contributions of these meteorological aspects became minor when including wind direction, especially when approaching major emission sources. The bioaccumulation integration time towards meteorological variations was on a seasonal basis (1-2 months) but the wind direction and thus local emissions also relied on a longer time scale (12 months). This showed that the contribution of meteorological conditions may be prevalent in remote places, while secondary in polluted areas, and should be definitely taken into account regarding long-term lichen biomonitoring and inter-annual comparisons. In the same time, a quadruple sampling in each site revealed a high homogeneity among supporting tree species and topography. The resulting uncertainty, including sampling, preparation and analysis was below 30% when comfortable analytical conditions were achieved. Finally, the occurrence of unexpected events such as a major forest fire, permitted to evaluate that this type of short, although intense, events did not have a strong influence on PAH and metals bioaccumulation by lichen.

Effect of Cu on the fluorescence of the Cu-hyperaccumulator lichen Stereocaulon sorediiferum

Stereocaulon sorediiferum is expected to be a Cu-hyperaccumulator lichen and has fluorescent substances. To clarify the relationship between the fluorescence (FL) of the lichen and its Cu concentration, we collected S. sorediiferum samples at Cu-contaminated and uncontaminated sites in Japan, determined the concentration of Cu, K, Mg, Al, Ca, Mn, Fe, Zn, chlorophyll a,b, and total carotenoids in them, analyzed lichen secondary metabolites and fluorescent substances extracted from them, and measured the FL of them and their extracts. We found that the FL intensity of S. sorediiferum samples is significantly negatively correlated with their Cu concentration. The application of its FL for Cu monitoring may allow a new nondestructive quantitative method for assessing Cu contamination. The spectroscopic and chromatographic analysis shows that the fluorescent substances negatively correlated with Cu concentration are not major lichen secondary metabolites (lobaric acid and atranorin) and remain after immersion in acetone. The correlation analysis and the comparison with the causal relationship between Cu concentration and the chlorophyll a/b ratio suggest that the reason for the decrease in FL intensity with increasing Cu concentration is a structural change of the fluorescent substances by accumulated Cu. These findings lead to a better understanding of the relationship between the FL of S. sorediiferum and its Cu concentration and provide new insights into fluorescent lichen substances.

Air quality assessment in different environmental scenarios by the determination of typical heavy metals and Persistent Organic Pollutants in native lichen Xanthoria parietina

The study was aimed to evaluate the ability of native lichen Xanthoria (X.) parietina to biomonitor and bioaccumulate some heavy metals (As, Cd, Co, Cr, Ni, Pb), PAHs, PCDDs, PCDFs, PCBs and PBDEs and to evaluate the use of the native X. parietina as a multi-tracer tool for scenarios characterized by different anthropogenic pressures. Samples of native X. parietina were collected in six different sites (two green, two residential and two industrial areas, respectively) and analyzed for the target compounds. The results show that X. parietina was a useful tool for the biomonitoring of air quality in the selected areas, and was able to bioaccumulate all the studied metals and POPs. In particular, the total concentrations dry weight (dw) ranged between 8.1 and 103.4 mg kg^-1 for metals, from 113 × 10³ to 183 × 10³ ng kg^-1 for PAHs, from 868 to 7685 ng kg^-1 for PCBs, from 14.3 to 113.8 ng kg^-1 for PCDDs/Fs (∑TEq = 0.9-7.1), and from 194 to 554 ng kg^-1 for PBDEs. Besides, in general, the levels of analytes recovered in the different samples of lichen show an increasing trend from green to industrial sites, especially for PCBs (mean values equal to 1218, 4253 and 7192 ng kg^-1 respectively for green, residential and industrial areas). The statistical approach, based on Pearson's correlation and principal component analysis tests, showed that one of the industrial sites was well-separated from the others, that resulted grouped due to some similarities.