Content of lead and cadmium in aboveground plant organs of grasses growing on the areas adjacent to a route of big traffic

Ecotoxicity of soil Pb pollution reflected by soil β-glucosidase: Comparison of extracellular and intracellular enzyme pool

Lead (Pb) is a major environmental pollutant that threatens the soil environment and human health. Monitoring and assessing Pb toxicity on soil health are of paramount importance to the public. To use soil enzymes as biological indicators of Pb contamination, herein, the responses of soil β-glucosidase (BG) in different pools of soil (total, intracellular and extracellular enzyme) to Pb contamination were investigated. The results indicated that the intra-BG (intracellular BG) and extra-BG (extracellular BG) responded differently to Pb contamination. While the addition of Pb caused a significant inhibition of the intra-BG activities, the extra-BG activities were only slightly inhibited. Pb showed a non-competitive inhibition to extra-BG, while both non-competitive and uncompetitive inhibition were observed for intra-BG in the tested soils. The dose-response modeling was used to calculate ecological dose ED₁₀, which represents the concentration of Pb pollutant that causes a 10 % reduction in V_max, to express the ecological consequences of Pb contamination. A positive correlation was found between ecological dose ED₁₀ values of intra-BG and soil total nitrogen (p < 0.05), which suggests soil properties may influence Pb toxicity to soil BG. Based on the differences in ED₁₀ and inhibition rate among different enzyme pools, this study suggests that the intra-BG is more sensitive for Pb contamination assessment. From this, we propose that intra-BG should be considered when evaluating Pb contamination using soil enzymes as indicators.

Impact of Car Traffic on Metal Accumulation in Soils and Plants Growing Close to a Motorway (Eastern Slovakia)

The paper evaluates the impact of car transport on the distribution and accumulation of Zn, Cu, Pb and Cd in soils, as well as in the vegetation near a newly built R4 motorway Košice-Milhosť (Slovakia). Samples were taken from surface humus layer (litter) and 0−5, 10−20 and 20−30 cm mineral layers of Cambisol and Luvisol, as well as from assimilatory organs of Fraxinus excelsior, Quercus cerris, Quercus rubra, Negundo aceroides and Anthriscus sylvestris growing in the segments of geobiocoenosis Querci-Fageta Typica. The concentrations of total Zn and Cu were determined using SensAA AAS and the total concentrations of Cd and Pb using an instrument iCE 3000 Series AAS-F. Contamination factor (CF) values showed that surface humus layer of both soil units is moderately contaminated with Zn (1 ≤ CF ˂ 3), low contaminated with Cu (CF ˂ 1) and considerably contaminated with Pb and Cd (3 ≤ CF ˂ 6). Contamination of the surface humus layer of Luvisol with Pb is very high (CF > 6), while in the case of mineral layers with Zn and Cu it is low (CF ˂ 1). The mineral layers of Luvisol are moderately contaminated with Pb and Cd (1 ≤ CF ˂ 3) and Cambisol layers with Zn, Cu, Pb and Cd. For the group of 5 tested plants, higher values of toxic elements in the leaves were observed on Luvisol compared to Cambisol. However, only Cu conconcentrations in Luvisol significantly correlated with Cu concentrations in plants (r > 0.4 or r < 0.6). The same can be said for Zn concentrations in Cambisol (r > 0.8). The best indicator of the environment polluted by car traffic appears to be A. sylvestris. Transfer coefficients (TC ˃ 1) revealed that this species concentrated the most Zn and Cu on Luvisol and close to 1 are also the TC values found for Cu in F. excelsior and Q. cerris leaves taken on Luvisol. Lead is accumulated most efficiently in N. aceroides leaves and Cd in A. sylvestris leaves regardless of soil unit. Compared to background values, the total concentrations of trace elements in soils and plants were significantly higher and point to the pollution of forest ecosystems already in the initial stage of motorway operation.

How can vegetation protect us from air pollution? A critical review on green spaces' mitigation abilities for air-borne particles from a public health perspective - with implications for urban planning

Air pollution causes the largest death toll among environmental risks globally, but interventions to purify ambient air remain inadequate. Vegetation and green spaces have shown reductive effects on air-borne pollutants concentrations, especially of particulate matter (PM). Guidance on green space utilisation for air quality control remains scarce, however, as does its application in practise. To strengthen the foundation for research and interventions, we undertook a critical review of the state of science from a public health perspective. We used inter-disciplinary search strategies for published reviews on green spaces and air pollution in key scientific databases. Using the PRISMA checklist, we systematically identified reviews with quantitative analyses. For each of the presented PM mitigation mechanisms, we conducted additional searches focused on the most recent articles published between 2016 and early 2021. The included reviews differentiate three mitigation mechanisms of green spaces for PM: deposition, dispersion and modification. The most studied mechanism is deposition, particularly measures of mass and settling velocity of PM on plant leaves. We consolidate how green space setups differ by scale and context in their potentials to reduce peak exposures, stationary (point) or mobile (line) pollution sources, and the potentially most harmful PM components. The assessed findings suggest diverse optimisation options for green space interventions, particularly concerning plant selection, spatial setup, ventilation and maintenance - all alongside the consideration of supplementary vegetation effects like on temperature or water. Green spaces' reductive effects on air-borne PM concentrations are considerable, multi-mechanistic and varied by scale, context and vegetation characteristics. Such effect-modifying factors must be considered when rethinking public space design, as accelerated by the COVID-19 pandemic. Weak linkages amid involved disciplines motivate the development of a research framework to strengthen health-oriented guidance. We conclude on an urgent need for an integrated and risk-based approach to PM mitigation through green space interventions.

Lead contamination alters enzyme activities and microbial composition in the rhizosphere soil of the hyperaccumulator Pogonatherum crinitum

Pogonatherum crinitum is a promising lead (Pb) hyperaccumulator; however, the effects of Pb contamination on P. crinitum rhizosphere soil enzymatic activities and microbial composition remain largely unexplored. Thus, an indoor experiment was conducted by cultivating P. crinitum seedlings and exposing them to four Pb concentrations (0, 1,000, 2000 and 3000 mg/kg Pb). Protease, urease, acid phosphatase and invertase activities were determined using standard methods while soil bacterial composition was determined by 16 S rDNA sequencing. The results showed that rhizosphere soil acid phosphatase activity significantly increased with increasing Pb concentration, while urease activity was significantly greater in rhizosphere soil contaminated with 1000 and 2000 mg/kg than in the control. There was a clear shift in bacterial composition during phytoremediation by P. crinitum. Compared to the control, Bacteroidetes was more abundant in all Pb-contaminated soils, Actinobacteria was more abundant in 1000 mg/kg Pb-treated soil, and Firmicutes was more abundant in 3000 mg/kg Pb-treated soil. Positive correlations were observed between dominant bacterial phyla and soil enzyme activities. Metabolic pathways, such as ABC transporter, quinine reductase, and ATP-binding protein were significantly increased in rhizosphere soil bacteria with Pb contamination. In conclusion, Pb contamination differentially influenced the activities of rhizosphere soil enzymes, specifically increasing acid phosphatase and urease activities, and alters the dominance of soil bacteria through up-regulation of genes related to some metabolic pathways. The strong correlations between dominant bacterial phyla and enzymatic activities suggest synergetic effects on the growth of P. crinitum during Pb contamination.

Phytoremediation potential of twelve wild plant species for toxic elements in a contaminated soil

Green remediation of soils highly contaminated with potentially toxic elements (PTEs) can be achieved using suitable plants. Such phytoremediation procedure often takes into consideration PTE concentrations in plants only, but not produced biomass. Phytoremediation potential of certain species of wild plants for PTEs in contaminated floodplain soils has not been assessed yet. Therefore, in this work 12 native species were tested, 3 of which (Poa angustifolia, Galium mollugo, and Stellaria holostea) to our knowledge have never been used before, in a two-year pot experiment and assessed their potential as phytoremediation species. The results showed that plant PTE concentrations were dramatically elevated for Cd and Zn in Alopecurus pratensis, Arrhenatherum elatius, Bromus inermis, Artemisia vulgaris, Achillea millefolium, Galium mollugo, Stellaria holostea, and Silene vulgaris. A. vulgaris was by far the most highly PTE absorbing plant among the 12 tested in this work, especially concerning Zn, Cd, and to a lesser degree Cu and Ni. Also, among species non-studied-before, G. mollugo and S. holostea were characterized by high Zn and Cd uptake, while P. angustifolia did not. Assessing the number of harvests necessary to decrease soil PTE to half of the initial concentrations, it was found that for Cd plants would achieve site phytoremediation within 8 (A. vulgaris) to 28 (S. holostea) and 51 (G. mollugo) harvests, while for Zn, harvests ranged from 104 (A. vulgaris) to 209 (S. holostea), and 251 (A. millefolium). A clear grouping of the tested species according to their functional type was evident. Herbaceous species were collectively more efficient than grasses in PTE uptake combined by high biomass accumulation; thus, they may act as key-species in a phytoremediation-related concept. Our approach puts phytoremediation into a practical perspective as to whether the process can be achieved within a measureable amount of time. In conclusion, A. vulgaris behaved as a hyperaccumulator plant species in our heavily contaminated soil, while never-studied-before G. mollugo and S. holostea also had a hyperaccumulator behavior, especially for Cd and Zn. Although more research is necessary for conclusive results, our study is pivotal in that it would help in assessing plant species as potential phytoremediation species in heavily contaminated soils.

Heavy metal concentrations in roadside plants (Achillea wilhelmsii and Cardaria draba) and soils along some highways in Hamedan, west of Iran

The present study was conducted to analyze the effects of traffic volumes on Cd, Cu, Pb, Ni, and Zn contents in roadside soils and in two dominant herbaceous species (Achillea wilhelmsii and Cardaria draba) along highways and to evaluate the dynamic characteristics of these elements and their accumulation by the aerial parts and roots of these herbaceous species. The plant samples were collected along 700 m of a 9-km segment of each of the three major highways in Hamedan Province (West Iran) with different traffic volumes: Hamedan-Goltapeh (HG), Hamedan-Razan (HR), and Hamedan-Kermanshah (HK). The results indicated that the mean contents of Cd, Cu, Pb, Ni, and Zn in the soil samples were 0.26, 18.74, 14.98, 18.21, and 62.25 mg kg^-1, respectively. Furthermore, the mean contents of elements (mg kg^-1) in aerial parts of A. wilhelmsii were 0.16 for Cd, 4.52 for Cu, 1.91 for Pb, 1.70 for Ni, and 44.80 for Zn, while in the aerial part samples of C. draba, the concentrations (mg kg^-1) and the mean contents were 0.16, 2.29, 2.58, 1.60, and 31.29, respectively. This meant that the traffic volume affected the contents of the metals in the soil and the herbaceous species. The metal content in herbaceous tissues varied significantly between plant species. A. wilhelmsii tended to accumulate the metals in the roots while C. draba retained them mostly in the aerial parts. The significant positive correlations of Cd, Cu, Ni, and Zn content in root and aerial parts of the herbaceous plant with those found in the soil samples showed the potential of the studied species for application in biomonitoring studies. Comprehensive analysis (effect of traffic volumes and relationships between the content of elements in plant tissues and soil samples) indicated that Cu in both herbaceous plants was mainly derived from soil, while A. wilhelmsii absorbed Cd and C. draba absorbed Zn mainly through the stomata from atmospheric depositions. Without considering atmospheric depositions due to intense traffic volumes, in A. wilhelmsii, the translocation factor (TF) values of Cu and Zn were 1.06 and 1.44, respectively and in C. draba, the TF values of Cd, Cu, and Pb were 1.06, 1.09, and 1.13, respectively, thus suggesting that both herbaceous species had high potentials for transferring metals from the roots to aerial parts.

Lead and Cadmium Content in Grass Growing Near An Expressway

The purpose of the study was to evaluate the effect of distance from a road on lead and cadmium content in grass species near an expressway and to assess bioaccumulation of these elements by morphological parts of the plants. The material for the research was the following grass species in their flowering stage: Dactylis glomerata, Arrenatherum elatius, and Alopecurus pratensis. Plant samples were collected along the international E30 road, the ring-road of Siedlce, in May 2015. A 9-km road section was examined with samples collected on both sides, covering a stretch of 700 m, at the following distances from the edge of the road: 1, 5, 10, and 15 m. Five samples of each plant species and at each distance from the road were collected. Lead and cadmium concentration was determined with the AAS method. The largest amounts of Pb were absorbed by A. pratensis L. (3.843 mg kg^-1DM), while the lowest by A. elatius L. (2.523 mg kg^-1DM). Of the above plants, the highest amount of Cd (0.286 mg kg^-1DM) was accumulated by D. glomerata L. Underground parts of the grass species accumulated greater amounts of Pb and Cd than aboveground parts. It indicates that considerable amounts of heavy metals released by expressway vehicles contaminated the soil. The highest content of Pb and Cd was found in the grass growing at a distance of 5 m from the edge of the roadway, and this applies both to underground and aboveground parts.

Effects of road proximity on heavy metal concentrations in soils and common roadside plants in Southern California

Concerns about motor vehicle emissions on human health are typically focused on aerial pollution and are regulated via controls on tailpipe emissions. However, vehicles also contribute heavy metal emissions through non-tailpipe pathways (e.g., brake wear, tire particulates). The metal pollutants produced via both tailpipe and non-tailpipe pathways pose threats to both human and ecosystem health long after they have settled from the atmosphere largely via contamination of soils and plants. In this study, we examined the effect of vehicular pollution on soils and plants in five paired sites in Gaviota, CA. In each site, we examined the effect of proximity to road on heavy metal concentrations (cadmium, nickel, lead, and zinc) in four of the most common roadside plant species-Melilotus indicus, Herschfeldia incana, Avena sativa, and Artemisia californica-as well as on soil metal concentrations. Then, to look at potential effects of road proximity and associated metal pollution on plants, we also examined the carbon and nitrogen ratios of all the plant samples. We found strong and significant effects of proximity to road on concentrations of all heavy metals in plants; plants in close proximity to roads had metal concentrations between 8 and 11 times higher than plants farther from roads. Plant C:N ratios also varied strongly among site types and were always higher in close proximity to roads as compared to farther off roads, potentially indicating broader effects of road proximity to plant ecology and leaf quality for consumers in the region.

Relationship between concentration of rare earth elements in soil and their distribution in plants growing near a frequented road

Rare earth elements (REEs) are a group of elements whose concentration in numerous environmental matrices continues to increase; therefore, the use of biological methods for their removal from soil would seem to be a safe and reasonable approach. The aim of this study was to estimate the phytoextraction efficiency and distribution of light and heavy (LREEs and HREEs) rare earth elements by three herbaceous plant species: Artemisia vulgaris L., Taraxacum officinale F.H. Wigg. and Trifolium repens L., growing at a distance of 1, 10, and 25 m from the edge of a frequented road in Poland. The concentration of REEs in soil and plants was highly correlated (r > 0.9300), which indicates the high potential of the studied plant species to phytoextraction of these elements. The largest proportion of REEs was from the group of LREEs, whereas HREEs comprised only an inconsiderable portion of the REEs group. The dominant elements in the group of LREEs were Nd and Ce, while Er was dominant in the HREEs group. Differences in the amounts of these elements influenced the total concentration of LREEs, HREEs, and finally REEs and their quantities which decreased with distance from the road. According to the Friedman rank sum test, significant differences in REEs concentration, mainly between A. vulgaris L., and T. repens L. were observed for plants growing at all three distances from the road. The same relation between A. vulgaris L. and T. officinale was observed. The efficiency of LREEs and REEs phytoextraction in the whole biomass of plants growing at all distances from the road was A. vulgaris L. > T. officinale L. > T. repens L. For HREEs, the same relationship was recorded only for plants growing at the distance 1 m from the road. Bioconcentration factor (BCF) values for LREEs and HREEs were respectively higher and lower than 1 for all studied plant species regardless of the distance from the road. The studied herbaceous plant species were able to effectively phytoextract LREEs only (BCF > 1); therefore, these plants, which are commonly present near roads, could be a useful tool for removing this group of REEs from contaminated soil.

Traffic-emitted metal status and uptake by Carex meyeriana Kunth and Thelypteris palustris var. pubescens Fernald growing in roadside turfy swamp in the Changbai Mountain area, China

Six traffic-emitted metals (Cr, Zn, Cu, Cd, Pb, and Ni) were determined in soil and plants for below- and aboveground parts along different distances from highway to evaluate their behavior and uptake by Carex meyeriana Kunth and Thelypteris palustris var. pubescens Fernald growing in turfy swamps. The results indicated that the different plant tissues showed significantly different levels of metal content. Nonlinear regression analysis indicated that metal contents leveled off at constant values before they decreased as the distance from the roadside increased. The high R² values of the regression model indicated good fit of the exponential function applied to depict the distribution pattern of the metal elements. It was deduced that Cr, Cu, and Cd in Thelypteris palustris var. pubescens Fernald were mainly derived from the soil; Carex meyeriana Kunth and Thelypteris palustris var. pubescens Fernald absorbed Pb mainly through the stomata from atmospheric depositions; Cr, Cu, and Cd in Carex meyeriana Kunth and Zn in Thelypteris palustris var. pubescens Fernald were mainly affected by soil and atmospheric depositions. After excluding the effects of traffic, only the bioaccumulation factor of Cd (1.34) in Carex meyeriana Kunth and the translocation factor of Zn (1.13) in Thelypteris palustris var. pubescens Fernald were greater than 1, suggesting that Carex meyeriana Kunth could be a good candidate for assimilating Cd from soils and Thelypteris palustris var. pubescens Fernald could be suitable for the phytoextraction of Zn.

Using expansive grasses for monitoring heavy metal pollution in the vicinity of roads

We propose a method for monitoring heavy metal deposition in the vicinity of roads using the leaf surfaces of two expansive grass species which are greatly abundant. A principle of the proposed procedure is to minimize the number of operations in collecting and preparing samples for analysis. The monitored elements are extracted from the leaf surfaces using dilute nitric acid directly in the sample-collection bottle. The ensuing steps, then, are only to filter the extraction solution and the elemental analysis itself. The verification results indicate that the selected grasses Calamagrostis epigejos and Arrhenatherum elatius are well suited to the proposed procedure. Selected heavy metals (Zn, Cu, Pb, Ni, Cr, and Cd) in concentrations appropriate for direct determination using methods of elemental analysis can be extracted from the surface of leaves of these species collected in the vicinity of roads with medium traffic loads. Comparing the two species showed that each had a different relationship between the amounts of deposited heavy metals and distance from the road. This disparity can be explained by specific morphological properties of the two species' leaf surfaces. Due to the abundant occurrence of the two species and the method's general simplicity and ready availability, we regard the proposed approach to constitute a broadly usable and repeatable one for producing reproducible results.

Traffic-related metal(loid) status and uptake by dominant plants growing naturally in roadside soils in the Tibetan plateau, China

To understand traffic-related metal(loid) status and uptake by dominant plants growing naturally in roadside soils in the Tibetan plateau, China, aboveground parts and root samples of three dominant plant species (Kalidium slenderbranch, Stipa purpurea, Kobresia pygmaea) were collected along the Qinghai-Tibet highway, and were analyzed for concentrations of traffic-related metal(loid)s such as chromium (Cr), zinc (Zn), copper (Cu), cadmium (Cd), arsenic (As), and lead (Pb). The results indicated that concentrations of metal(loid)s in plant tissues varied greatly among plant species and sites. Tissue distribution of metal(loid)s was significantly related to distance and demonstrated variability as an exponential function of traffic proximity. It was deduced that Cd in Kalidium slenderbranch and Cu and Zn in S. purpurea were mainly derived from soil; Kalidium slenderbranch and Kobresia pygmaea absorbed Zn, and S. purpurea absorbed Cd, mainly through stomata, from atmospheric deposition; enrichments of Pb and As in S. purpurea presented similar characteristics to those of Cd and Pb in Kobresia pygmaea and were affected by both soil and atmospheric deposition. After excluding the effects of the traffic, the highest value obtained for metal(loid)-translocation capacity (7.51 for translocation factor, TF) was observed for S. purpurea collected from Tuotuohe, while the lowest value for metal(loid)-uptake capacity (0.015 for bioaccumulation factor, BF) was for Kalidium slenderbranch collected from Golmud. The three plant species showed limited soil-to-root transfer of metal(loid)s, possibly due to the high soil pH along the Qinghai-Tibet highway, but demonstrated great potential for metal(loid) transfer from roots to aboveground parts.

Preconception Care: A New Standard of Care within Maternal Health Services

Emerging research suggests that much pediatric affliction has origins in the vulnerable phase of fetal development. Prenatal factors including deficiency of various nutrients and exposure to assorted toxicants are major etiological determinants of myriad obstetrical complications, pediatric chronic diseases, and perhaps some genetic mutations. With recent recognition that modifiable environmental determinants, rather than genetic predestination, are the etiological source of most chronic illness, modification of environmental factors prior to conception offers the possibility of precluding various mental and physical health conditions. Environmental and lifestyle modification through informed patient choice is possible but evidence confirms that, with little to no training in clinical nutrition, toxicology, or environmental exposures, most clinicians are ill-equipped to counsel patients about this important area. With the totality of available scientific evidence that now exists on the potential to modify disease-causing gestational determinants, failure to take necessary precautionary action may render members of the medical community collectively and individually culpable for preventable illness in children. We advocate for environmental health education of maternity health professionals and the widespread adoption and implementation of preconception care. This will necessitate the translation of emerging knowledge from recent research literature, to health professionals, to reproductive-aged women, and to society at large.

The Risk Factors of Child Lead Poisoning in China: A Meta-Analysis

BACKGROUND

To investigate the risk factors of child lead poisoning in China.

METHODS

A document retrieval was performed using MeSH (Medical subject heading terms) and key words. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the studies, and the pooled odd ratios with a 95% confidence interval were used to identify the risk factors. We employed Review Manager 5.2 and Stata 10.0 to analyze the data. Heterogeneity was assessed by both the Chi-square and I² tests, and publication bias was evaluated using a funnel plot and Egger's test.

RESULTS

Thirty-four articles reporting 13,587 lead-poisoned children met the inclusion criteria. Unhealthy lifestyle and behaviors, environmental pollution around the home and potential for parents' occupational exposure to lead were risk factors of child lead poisoning in the pooled analyses. Our assessments yielded no severe publication biases.

CONCLUSIONS

Seventeen risk factors are associated with child lead poisoning, which can be used to identify high-risk children. Health education and promotion campaigns should be designed in order to minimize or prevent child lead poisoning in China.

Metal Content in Dandelion (Taraxacum officinale) Leaves: Influence of Vehicular Traffic and Safety upon Consumption as Food

The widespread distribution of the common dandelion, that is,Taraxacum officinale, along with its ability to tolerate a wide range of environmental conditions, makes this plant a good candidate as biological monitor of environmental metal contamination.Taraxacum officinaleleaves growing spontaneously in meadows and along the streets are traditionally picked up and eaten in Italy as salad, so it is important to know the concentrations of potentially toxic elements contained in them from the point of view of food safety. For these reasons the concentrations of Cd, Cr, Cu, Fe, Mn, Pb, and Zn were determined in dandelion leaf and underlying soil samples collected at 12 sites in the province of Cuneo (Piedmont, Italy) in the vicinity of streets or roundabouts. The concentrations were compared with reference values for plant and soils and with maximum allowable concentrations in edible vegetables. Neither dandelion nor soil samples were found to be polluted by metals, but the comparison with limits for vegetables suggests that caution should be used in consuming spontaneously growing vegetables.

Content of Zinc and Copper in Selected Plants Growing Along a Motorway

In 2011 a study was carried out analyzing the effects of road traffic on bioaccumulation of zinc and copper in selected species of dicotyledonous plants growing on adjacent grasslands. To do the research the plants were sampled from the 9-km-long Siedlce bypass, a part of the international route E-30. They were collected during the flowering stage, at following distances from the road: 1, 5, 10, 15 m. The content of zinc and copper was determined with the AAS method, with dry mineralisation done before. The highest concentration of the elements, regardless of the distance from the road, was found in Taraxacum spec. Among the tested plants, the lowest zinc content was in Vicia cracca, and the lowest copper content in Rumex acetosa. The limit for copper content was exceeded in Taraxacum spec. and, slightly, in Achillea millefolium growing at the roadside, closest to the roadway.