Role of the salt glands of Armeria maritima (halophyte) in removal of lead from tissues.

Armeria maritima is a halophyte exhibiting a strong tolerance to heavy metals. It grows on zinc-lead waste heaps. This study aimed to determine the role of salt glands in the removal of lead (Pb) from plants and to trace the path of lead from the shoots to the salt glands on the surface of leaves. Mechanisms allowing high tolerance to lead in A. maritima were also evaluated. These examinations were conducted on a lead-tolerant population and a lead-sensitive plant population. The plants were treated with Pb(NO3)2 and the path of lead was traced from the roots to the leaves. The lead-tolerant population transported twice as much lead as the sensitive population. The action of the salt glands resulted in 40% of the leaf lead content in the lead-tolerant population being expelled onto the surface of the leaves. These features indicate the high phytoremediation capabilities of these halophyte plants. The excretion of multi-ionic solutes by the salt glands results in the appearance of tiny crystals on the surface of the leaves. In this publication, for the first time, an attempt was made to determine what chemical compounds build up these crystals and to determine their crystal structure. Solving this problem was possible through the usage of single-crystal X-ray structural analysis.

Micro-Evolutionary Processes in Armeria maritima at Metalliferous Sites.

Tolerance to heavy metals in plants is a model process used to study adaptations to extremely unfavorable environments. One species capable of colonizing areas with high contents of heavy metals is Armeria maritima (Mill.) Wild. A. maritima plants growing in metalliferous areas differ in their morphological features and tolerance levels to heavy metals compared to individuals of the same species growing in non-metalliferous areas. The A. maritima adaptations to heavy metals occur at the organismal, tissue, and cellular levels (e.g., the retention of metals in roots, enrichment of the oldest leaves with metals, accumulation of metals in trichomes, and excretion of metals by salt glands of leaf epidermis). This species also undergoes physiological and biochemical adaptations (e.g., the accumulation of metals in vacuoles of the root's tannic cells and secretion of such compounds as glutathione, organic acids, or HSP17). This work reviews the current knowledge on A. maritima adaptations to heavy metals occurring in zinc-lead waste heaps and the species' genetic variation from exposure to such habitats. A. maritima is an excellent example of microevolution processes in plants inhabiting anthropogenically changed areas.

Survival on railway tracks of Geranium robertianum-a glyphosate-tolerant plant.

Geranium robertianum is a herbaceous plant that prefers shady and fertile forest habitats. However, it also occurs on railway tracks, where there are difficult conditions for plant growth and regular herbicide spraying (in high concentrations, twice a year). One of the most commonly used herbicides in railway areas is glyphosate. The effect of the glyphosate on the G. robertianum plants found on railway tracks and in nearby forests in north-eastern Poland was checked. The aim of the study was to explain how G. robertianum can survive on railway tracks despite spraying with the glyphosate. Increased tolerance to the glyphosate of the G. robertianum plants from track populations was demonstrated compared to the plants from forest populations that had not previously been in contact with the herbicide. After 35 days after treatment with the herbicide, 75% of the plants from the observed forest populations withered, while only 38% did from the track populations. Ultrastructure of plant leaf cells from forest populations was strongly disturbed, which was not observed in plants from track populations. It was also shown that plants from track populations accumulated more glyphosate and AMPA in their tissues than plants from forest populations. The obtained results indicate that long-term use of herbicides may cause formation of biotypes of plants resistant to a given herbicide. This fact explains the possibility of G. robertianum occurring on railway tracks, despite spraying with the glyphosate. It is also a manifestation of microevolutionary processes.

A new taxon within Biscutella laevigata L. (Brassicaceae) endemic to calamine areas in southern Poland.

A new taxon Biscutella laevigata subsp. woycickii (Brassicaceae) is described from southern Poland. The taxon is similar to B. laevigata subsp. gracilis, but differs in having thin, light-green rosette leaves very densely covered by simple non-glandular trichomes, smaller seeds and the ability to tolerate and accumulate high amounts of heavy metals. This new taxon is supported by results of cultivation experiments, as well as genetic and paleobotanical evidence.

Air Contamination by Mercury, Emissions and Transformations-a Review.

The present and future air contamination by mercury is and will continue to be a serious risk for human health. This publication presents a review of the literature dealing with the issues related to air contamination by mercury and its transformations as well as its natural and anthropogenic emissions. The assessment of mercury emissions into the air poses serious methodological problems. It is particularly difficult to distinguish between natural and anthropogenic emissions and re-emissions from lands and oceans, including past emissions. At present, the largest emission sources include fuel combustion, mainly that of coal, and "artisanal and small-scale gold mining" (ASGM). The distinctly highest emissions can be found in South and South-East Asia, accounting for 45% of the global emissions. The emissions of natural origin and re-emissions are estimated at 45-66% of the global emissions, with the largest part of emissions originating in the oceans. Forecasts on the future emission levels are not unambiguous; however, most forecasts do not provide for reductions in emissions. Ninety-five percent of mercury occurring in the air is Hg0-GEM, and its residence time in the air is estimated at 6 to 18 months. The residence times of its HgII-GOM and that in Hgp-TPM are estimated at hours and days. The highest mercury concentrations in the air can be found in the areas of mercury mines and those of ASGM. Since 1980 when it reached its maximum, the global background mercury concentration in the air has remained at a relatively constant level.

Mercury in Marine and Oceanic Waters-a Review.

Mercury contamination in water has been an issue to the environment and human health. In this article, mercury in marine and oceanic waters has been reviewed. In the aquatic environment, mercury occurs in many forms, which depend on the oxidation-reduction conditions. These forms have been briefly described in this article. Mercury concentrations in marine waters in the different parts of the world have been presented. In the relevant literature, two models describing the fate and behavior of mercury in saltwater reservoirs have been presented, a conceptual model which treats all the oceans as one ocean and the "ocean margin" model, providing that the ocean margins manifested themselves as the convergence of continents and oceans, covering such geological features, such as estuaries, inland seas, and the continental shelf. These two conceptual models have been summarized in the text. The mercury content in benthic sediments usually reflects is level in the water reservoir, particularly in reservoirs situated in contaminated areas (mines, metallurgical plants, chemically protected crops). The concentrations of mercury and its compounds determined in the sediments in surface waters in the different parts of the world have been presented. Due to the fact that the pollution caused by mercury is a serious threat for the marine environment, the short paragraph about mercury bioaccumulation in aquatic organisms has been included. The cited data demonstrated a large scatter of mercury contents both between the fish species and the water areas. Mathematical models, valuable tools which provide information about the possible responses of ecosystems, developed to simulate mercury emissions, both at a small scale, for local water reservoirs, and at a global scale, as well as to model mercury bioaccumulation in the chain web of aquatic systems have been described.

Multidimensional evaluation of soil pollution from railway tracks.

Railway transport is a source of pollution to soils and living organisms by e.g. PAHs, PCBs, oil-derived products, pesticides and heavy metals. Soil toxicity evaluation requires chemical analyses, indicating the type and content of particular pollutants, as well as biological analyses, which allow assessing the reaction of organisms to these pollutants. This paper is focused on a multi-aspect evaluation of the degree of toxicity and pollution of soil in selected railway areas from north-eastern Poland by application of numerous biotests and chemical analyses. The soils were sampled on railway tracks from the following railway stations: Bialystok Fabryczny, Siemianówka, Hajnówka, Ilawa Glówna and Walily. The most toxic soils occur on the railway tracks at Bialystok Fabryczny and Siemianówka. They had a significant toxic effect on test organisms from various trophic levels. The contents of PAHs, PCBs, heavy metals, oil-derived hydrocarbons and pesticide residues were determined in the examined soils. In all cases the detected pollutants did not exceed the admissible levels. The highest content of oil-derived substances was noted in soils from Bialystok Fabryczny and concentrations were moderate in soils from Siemianówka. Although the pollutants determined in soils from railway tracks did not exceed the admissible values, they had a toxic effect on numerous test organisms from different trophic levels. This suggests a synergistic effect of low concentrations (within the admissible levels) of several pollutants together, which resulted in a toxic effect on the organisms. Thus, there is a strong need of not only chemical, but also ecotoxicological analyses during the evaluation of environmental conditions. Based on data obtained from biological and chemical analyses, we concluded that railway transport may pose a hazard to the natural environment to a larger extent that hitherto expected.