Physiological response and sulfur accumulation in the biomonitor Ramalina celastri in relation to the concentrations of SO2 and NO2 in urban environments

Physiological Response and Multi-Elemental Content in Lichens Growing on Agricultural Fences: A Pilot Study Comparing No-Tillage and Organic Cropping

The objective of this study is to compare the physiological response (content and degradation of photosynthetic pigments, membrane oxidation products and soluble proteins) and multi-element content of Ramalina celastri (lichenized fungi) growing on agricultural fences with no-tillage (associated with transgenic crops and agrochemical application), organic cropping and a non-cultivated area. We found that R. celastri did not differ in its physiological response to agricultural practices, except for the contents of chlorophyll b and phaeophytin a which were high in both cultivated areas. Lichens growing in organic cropping fields have higher arsenic, chromium, uranium and internal transition elements common in the earth's crust, possibly due to the greater resuspension of the material during soil tillage. Lichens that grow on posts close to no-tillage field had higher bromine contents (present in numerous pesticides). We found evidence that R. celastri behaves as a tolerant species to air pollution in agricultural environments.

The current state of environmental pollution with sulfur dioxide (SO2) in Poland based on sulfur concentration in Scots pine needles

The current air pollution by SO₂ due to anthropogenic pressure in Poland was assessed based on sulfur concentrations in pine needles (Pinus sylvestris L.). On 308 monitoring sample plots located in pine stands distributed across Poland, measurements were conducted in mineral soil layers (0-10 cm, 10-40 cm, 40-100 cm) and in the soil organic layer (+5-0 cm). Samples of Scots pine foliage (current-year needles) were then collected, and the sulfur concentration in these needles was determined. Based on these data, a map of the spatial variability of sulfur concentrations in pine needles was drawn. The mean sulfur concentration in the pine needles was 854.8 mg kg^-1 in dry mass. Higher SO₂ emissions were noted in regions influenced by industry, such as the Upper Silesia and regions under strong urban pressure. Sulfur concentrations in Scots pine needles were related to the stands' degrees of defoliation. A comparison of the current sulfur concentrations in pine needles from biomonitoring in 2015-2016 with those from previous biomonitoring (in 1983-1985, by Dmuchowski and Bytnerowicz (1995) showed that air quality has improved and SO₂ emissions have decreased.

Influence of Meteorological Variables and Forest Fires Events on Air Quality in an Urban Area (Córdoba, Argentina)

Extreme environmental events, such as forest fires, are a major emission source of aerosols into the atmosphere. Thus, to investigate the contribution of local forest fires to urban particulate matter, we selected several forest fire indicators, such as number of heat sources, fire events, and burnt area, and collected particles smaller than 2.5 µm (PM_2.5) during a 2.5-year period in Cordoba City (Argentina). Temporal variation of PM_2.5 concentration and composition was described considering fire and nonfire periods, and the influence of meteorological variables was estimated as well. On average, PM_2.5 levels registered in Córdoba city during the study period were lower than values reported for other similar cities in Latin America, despite the fact that during wintertime an increase in PM_2.5 levels was observed due to the occurrence of thermal inversions. Several fire events taking place in the nearby hills around the city during winter and spring 2013 suggest that biomass burning was a strong contribution to urban particles levels, which is consistent with the significant correlation between PM_2.5 concentration and heat sources number. During fire periods, levels of Fe, Ca, and K, were significantly higher than in the nonfire periods, suggesting that these elements can be reliable forest fire markers.

Biomonitoring levels and trends of PAHs and synthetic musks associated with land use in urban environments

Polycyclic aromatic hydrocarbons (PAHs) are some of the most studied organic compounds in urban environments, due to their known adverse effects on human health and persistence in environmental matrices. During the last decade, new groups of organic compounds with an intensive use worldwide such as synthetic musks have been raising the interest of the scientific community given their toxicity and health effects. However, literature is still scarce in studies dealing with their concentration in the environment, especially in developing countries, where they are even more rare or non-existing at all. We employed leaves of Ligustrum lucidum to assess the concentrations of PAHs and synthetic musks in different land use areas in Cordoba city, therefore contributing with environmental information in Argentina. We found higher levels of PAHs in urban and industrial areas than in the peri-urban sampling sites, naphthalene being one of the dominant PAHs in all sampling areas. Regarding synthetic musk fragrances, polycyclic musks were the most contributing compounds and the highest levels found in industrial areas as well. A high environmental risk could be expected due to the frequent occurrence of galaxolide in addition to the high hazardous potential of phantolide, which was present in 50% of the samples. The results of the present study indicate that leaves of an urban ubiquitous tree can be used to assess the spatial behavior of both "classic" and "emerging" organic pollutants, allowing an assessment of urban air quality in areas where common air sampling devices are unavailable.

Land use and air quality in urban environments: Human health risk assessment due to inhalation of airborne particles

Particle matter (PM) and its associated compounds are a serious problem for urban air quality and a threat to human health. In the present study, we assessed the intraurban variation of PM, and characterized the human health risk associated to the inhalation of particles measured on PM filters, considering different land use areas in the urban area of Cordoba city (Argentina) and different age groups. To assess the intraurban variation of PM, a biomonitoring network of T. capillaris was established in 15 sampling sites with different land use and the bioaccumulation of Co, Cu, Fe, Mn, Ni, Pb and Zn was quantified. After that, particles were collected by instrumental monitors placed at the most representative sampling sites of each land use category and an inhalation risk was calculated. A remarkable intraurban difference in the heavy metals content measured in the biomonitors was observed, in relation with the sampling site land use. The higher content was detected at industrial areas as well as in sites with intense vehicular traffic. Mean PM₁₀ levels exceeded the standard suggested by the U.S. EPA in all land use areas, except for the downtown. Hazard Index values were below EPA's safe limit in all land use areas and in the different age groups. In contrast, the carcinogenic risk analysis showed that all urban areas exceeded the acceptable limit (1 × 10^-6), while the industrial sampling sites and the elder group presented a carcinogenic risk higher that the unacceptable limit. These findings validate the use of T. capillaris to assess intraurban air quality and also show there is an important intraurban variation in human health risk associated to different land use.

Modifications in the structure of the lichen Cladonia thallus in the aftermath of habitat contamination and implications for its heavy-metal accumulation capacity

Phenotypic traits of lichens can be greatly modified by environmental factors. Granulose thalli on soil and podetia, densely covered with granules, referring to common and widespread lichen Cladonia cervicornis subsp. verticillata were found near zinc smelter. The granules are stratified, filled with fungal medulla and heavily encrusted with calcium oxalate weddellite crystals, not observed on regularly developed thalli of the species. Phylogenetic analysis revealed that deformed granulose forms belong to this taxon, showing that the phenotypic plasticity of the lichens of Cladonia can lead to the emergence of features that do not coincide with the taxonomic definition of the species. The heavy-metal accumulation capacity of both granulose and regular form of primary and secondary lichen thallus, in relation to the element content in corresponding substrate, was determined. Granulose-modified thalli accumulate greater amounts of heavy metals than regular ones, meaning that the bioaccumulation property of a given species may be greatly affected by morphological modifications. The granulose forms are also characterised by considerably higher ratios of Cd, Pb and As concentrations in lichen samples in relation to the corresponding substrates than regular ones. This means that collection of variously formed thalli should be avoided in biomonitoring sampling procedures. The results indicate that a substantial part of the element load, in particular zinc, in the examined lichen thalli collected near the smelter originates from atmospheric fallout.

Correlations in the elemental and metabolic profiles of the lichenDirinaria pictaafter road traffic exposure

Diverse metabolites were identified in lichens and their correlations with heavy metals revealed metabolic toxicity and the detoxification mechanism.