The effects of plant traits and phylogeny on soil-to-plant transfer of 99Tc

Enhancing radiological monitoring of 137Cs in coastal environments using taxonomic signals in brown seaweeds

With the rapidly expanding global nuclear industry, more efficient and direct radiological monitoring approaches are needed to ensure the associated environmental health impacts and risk remain fully assessed and undertaken as robustly as possible. Conventionally, radiological monitoring in the environment consists of measuring a wide range of anthropogenically enhanced radionuclides present in selected environmental matrices and using generic transfer values for modelling and prediction that are not necessarily suitable in some situations. Previous studies have found links between taxonomy and radionuclide uptake in terrestrial plants and freshwater fish, but the marine context remains relatively unexplored. This preliminary study was aimed at investigating a similar relationship between brown seaweed, an important indicator in radiological monitoring programmes in the marine environment, and Caesium-137, an important radionuclide discharged to the marine environment. A linear mixed model was fitted using REsidual Maximum Likelihood (REML) to activity concentration data collected from literature published worldwide and other databases. The output from REML modelling was adjusted to the International Atomic Energy Agency (IAEA) quoted transfer value for all seaweed taxa in order to produce mean estimate transfer value for each species, which were then analysed by hierarchical ANalysis Of VAriance (ANOVA) based on the taxonomy of brown seaweeds. Transfer value was found to vary between taxa with increasing significance up the taxonomic hierarchy, suggesting a link to evolutionary history. This novel approach enables contextualisation of activity concentration measurements of important marine indicator species in relation to the wider community, allows prediction of unknown transfer values without the need to sample specific species and could, therefore, enhance radiological monitoring by providing accurate, taxon specific transfer values for use in dose assessments and models of radionuclide transfer in the environment.

The phytochemical profiling, pharmacological activities, and safety of malva sylvestris: a review

Malva sylvestris is a plant commonly found in Europe, Asia, and Africa. The leaves and flowers of this plant have been used for centuries in traditional medicine to treat various ailments such as cough, cold, diarrhoea, and constipation. Google Scholar, PubMed, Scopus, and Web of Science were used to search for relevant material on the phytochemical profiling and pharmacologic activities of Malva sylvestris. The techniques used in phytochemical profiling and the pharmacologic activity of each compound were extracted from the included studies, including in vitro, in vivo, and clinical studies. The phytochemical analysis of Malva sylvestris revealed that the leaves and flowers are the most commonly used parts of the plant and contain various bioactive compounds such as flavonoids, mucilages, terpenoids, phenol derivatives, coumarins, sterols, tannins, saponins, and alkaloids. These phytochemicals are responsible for the many pharmacological activities of Malva sylvestris, such as anti-inflammatory, antimicrobial, hepatoprotective, laxative, antiproliferative and antioxidant properties. This review has presented an overview of the antinociceptive and anti-inflammatory activities and the cytotoxic effects of Malva sylvestris on different types of cancer cells. It has also summarised the work on developing copper oxide nanoparticles using Malva sylvestris leaf extract and its potential use in food and medicine. This review aims to highlight the traditional uses, phytochemistry, pharmacological activities, and safety of Malva sylvestris.

Can models based on phylogeny be used to predict radionuclide activity concentrations in crops?

The modelling of transfer of radionuclides from soils to plants generally relies upon empirical soil-plant concentration ratios. Concentration ratios are often highly uncertain and are not available for many plant-radionuclide combinations. A number of papers published over the last 20 years have suggested that phylogenetic models could be used to make predictions of the radionuclide transfer to plants. Such a modelling approach would have the advantage that site factors (typically related to soils) are taken into account. For the first time we have compared predictions of Cs and Sr transfer to a range of crops grown on different soils. Predictions for both elements were generally acceptable (within an order of magnitude of observed data) but Sr concentrations were over predicted in fruits and tubers. This over prediction of Sr concentrations is likely to be because the phylogenetic models were fitted to data for green shoots. We conclude that phylogenetic models offer a number of advantages, but that they must be validated and, in future, parametrisation datasets need to include data on concentrations in edible plant parts and not just green shoots.

Soil to plant transfer of radionuclides: predicting the fate of multiple radioisotopes in plants

Predicting soil-to-plant transfer of radionuclides is restricted by the range of species for which concentration ratios (CRs) have been measured. Here the radioecological utility of meta-analyses of phylogenetic effects on alkali earth metals will be explored for applications such as 'gap-filling' of CRs, the identification of sentinel biomonitor plants and the selection of taxa for phytoremediation of radionuclide contaminated soils. REML modelling of extensive CR/concentration datasets shows that the concentrations in plants of Ca, Mg and Sr are significantly influenced by phylogeny. Phylogenetic effects of these elements are shown here to be similar. Ratios of Ca/Mg and Ca/Sr are known to be quite stable in plants so, assuming that Sr/Ra ratios are stable, phylogenetic effects and estimated mean CRs are used to predict Ra CRs for groups of plants with few measured data. Overall, there are well quantified plant variables that could contribute significantly to improving predictions of the fate radioisotopes in the soil-plant system.

Soil-to-soybean transfer of (99)Tc and its underground distribution in differently contaminated upland soils

Pot experiments were performed in a greenhouse to investigate the soil-to-soybean transfer of (99)Tc in two different upland soils labeled with (99)TcO4(-) in two contrasting ways. One was to mix the soil with a (99)TcO4(-) solution 26 d before sowing (pre-sowing deposition: PSD), and the other was to apply the solution onto the soil surface 44 d after sowing (growing-period deposition: GPD). The soil-to-plant transfer was quantified with the transfer factor (TF, ratio of the plant concentration to the average of at-planting and at-harvest soil concentrations) or the aggregated transfer factor (TFag, ratio of the plant concentration to the deposition density). For both the depositions, the transfer of (99)Tc to aerial parts decreased in the order of leaf > stem > pod > seed. TF values (dimensionless) from the PSD were 0.22 and 0.27 (no statistically significant difference) for mature dry seeds in the respective soils, whereas a 600-fold higher value occurred for dry leaves. The post-harvest concentrations of the PSD (99)Tc in the top 20 cm soils as a whole were about half the initial concentrations. Around 25% of the total applied activity remained in the GPD soils after the harvest. The post-harvest depth profiles of the GPD (99)Tc in the two soils showed similar patterns of logarithmic activity decrease with increasing soil depths. Only 1.5-4.3% of the total applied activity was removed through the harvested biomass (seeds, pods and stems), and it was estimated that a great part of the total pant uptake returned to the soil through the fallen leaves. TFag values (m(2) kg(-1)) were about 2-4 times higher for the GPD than for the PSD. This finding and generally high root uptake of Tc may indicate that the use of empirical deposition time-dependent TFag data is particularly important for predicting the plant concentrations of Tc after its growing-period deposition.

Ethnobotanical and scientific aspects of Malva sylvestris L.: a millennial herbal medicine

OBJECTIVES

Malva sylvestris L., known as common mallow, is native to Europe, North Africa and Asia. In the Mediterranean region, this species has a long history of use as food, and due to its therapeutic relevance, some parts of this plant have been employed in traditional and ethnoveterinary medicines. The leaves in particular have been reported to have potent anti-inflammatory, antioxidant, anti-complementary, anticancer and skin tissue integrity activity. Additionally, an anti-ulcerogenic effect was recently proven, demonstrating that the aqueous extract was more effective than cimetidine, a potent medicine used to treat gastric ulcers. Due to its wide use and medicinal importance, many studies have been conducted; however, the information in the literature is very extensive and disseminated, making it difficult to use.

KEY FINDINGS

A complete review involving the ethnobotanical and scientific aspects of M. sylvestris has been made. The research has provided evidence that M. sylvestris has potential use as a medicinal plant and has highlighted a need for more studies involving clinical and toxicological aspects of its use.

SUMMARY

This review can contribute to the field with its historical context, and by describing the progress made, new ideas for researchers can arise.