Urban Allotment Gardens for the Biomonitoring of Atmospheric Trace Element Pollution

Recent Advances in the Determination of Major and Trace Elements in Plants Using Inductively Coupled Plasma Optical Emission Spectrometry

Interest in measuring major and trace elements in plants has increased in recent years because of growing concerns about the elements' contribution to daily intakes or the health risks posed by ingesting vegetables contaminated by potentially toxic elements. The recent advances in using inductively coupled plasma atomic emission spectrometry (ICP-OES) to measure major and trace elements in plant samples are reviewed in the present work. The sample preparation before instrumental determination and the main advantages and limitations of ICP-OES are described. New trends in element extraction in liquid solutions using fewer toxic solvents and microextractions are observed in recently published literature. Even though ICP-OES is a well-established and routine technique, recent innovations to increase its performance have been found. Validated methods are needed to ensure the obtaining of reliable results. Much research has focused on assessing principal figures of merit, such as limits of detection, quantification, selectivity, working ranges, precision in terms of repeatability and reproducibility, and accuracy through spiked samples or certified reference materials analysis. According to the published literature, the ICP-OES technique, 50 years after the release of the first commercially available equipment, remains a powerful and highly recommended tool for element determination on a wide range of concentrations.

Assessment of lettuces grown in urban areas for human consumption and as bioindicators of atmospheric pollution

This study proposes using the network of urban gardens to grow vegetables and to monitor air quality, and it also evaluates whether food grown on a clean substrate in an urban environment is safe for consumption. For this purpose, lettuces were exposed to different degrees of air pollution in five locations in the city of Copenhagen, plus a reference site. Six specimens were placed at each site and, after the exposure period, half of each sample was washed. Subsamples were then digested by a total extraction method and a bioaccessible extraction method, and the concentration of 23 elements subsequently measured by ICP-MS. The results showed that exposed samples in areas of higher atmospheric pollution accumulated a larger amount of trace elements associated with typical urban sources. They also highlighted the importance of washing food to remove particles that adhere to their surface. However, bioaccessibility testing demonstrated the importance of including bioaccessibility in risk analyses and how this factor varies depending on the type of matrix. In this case, bioaccessibility was higher for plant tissue than for particulate matter. Lastly, metal concentrations in lettuce were compared with legal values and an analysis of daily intake showed that the levels in Copenhagen were within limits for the protection of human health.

Impact of streetlights on physiology, biochemistry and diversity of urban bryophyte: a case study on moss Semibarbula orientalis

The use of artificial light at night is a very basic symbol of urbanization and has distorted many ecological, biochemical and physiological phenomena in plants, which have settled for millions of years in the biological system. Continuous illumination of light significantly alters the circadian rhythm of all organisms. The present study was focused to understand the effects of continuous light (CL) on the biochemistry and physiology of moss Semibarbula orientalis. It was observed that H2O2 accumulation and activities of chlorophyllase, phenylalanine ammonia-lyase, superoxide dismutase and catalase enzymes significantly enhanced in plants growing under streetlights. Similarly, plants under CL showed a marked reduction in photosynthetic performance. Specific fluxes (ABS/RC, TR/RC, ET/RC), phenomenological fluxes (ABS/CS, TR/CS, ET/CS), density of photosystem-II, quantum yield of photosynthesis and chlorophyll concentration markedly declined in plants growing under streetlights. Depletion in performance indices (PIcs and PIabs) and primary and secondary photochemistry [PHIO/(1 − PHIO) and PSIO/(1 − PSIO)] were also noticed, which indicated failure of adaptive strategies of photosystem-II, resulting in the loss of biomass of S. orientalis. Biomass decline is also shown by a decrease in coverage, which reduces the bryophyte species richness of the chosen locations. Present studies clearly indicate that artificial light at night drastically affects the moss population. The reduction in the dominating species, S. orientalis, improves species evenness and results in a slow growth rate.

Are aerosols on the leaves of apricot trees (Prunus armeniaca) signalizing the activity of a hidden paleo-supervolcano in a steppe?

Aerosols on plant leaves make it possible to assess the quality of air in settlements. The purpose of this work was to assess the acidity and specific electrical conductivity of aerosol suspensions (by washing off aerosol particles from the leaves of apricot trees (Prunus armeniaca)), which characterize the air pollution in the residential area of the Svetly Yar settlement (Volgograd region, Russia) during the spring-summer of 2019. The research hypothesis was as follows: Acidic mineralized aerosols with a mixed source are present in Svetly Yar. The differences were checked by the Student's t-test and evaluated at the level of significance of p = 0.05. The results indicated the presence of acidic (pH = 4.56 + 0.02) and highly mineralized aerosols (EC = 130.41 + 0.17 μS/cm) in the ambient air of the Svetly Yar residential area during the spring-summer of 2019 and revealed environmental risks for the population in comparison with aerosol suspensions from a (relatively) clean location (pH = 6.46 + 0.02; EC = 37.61 + 0.19 μS/cm). The authors confirmed their hypothesis in favor of mixed source acidic mineralized aerosols in the residential area of the Svetly Yar village. The anthropogenic sources were the industrial zones of Svetly Yar, the southern part of the city of Volgograd and artificial sedimentation tanks in the southwestern part of Svetly Yar. A natural source of pollution in the vicinity of Svetly Yar may be hidden geologically active structures: faults in the Earth's crust, a salt diapir, an underground ancient semiactive volcanic zone on a steppe, etc.