Pb In Grass Research Articles

Risk assessment of heavy metals in children’s playgrounds in the Rabka Zdrój health resort / Zagrożenie metalami ciężkimi na placach zabaw w uzdrowisku dziecięcym Rabka - Zdrój

Abstract The problem of exposing to toxins in places frequented by people (especially children) for a longer time is an important aspect of environmental studies. Therefore, in Rabka-Zdrój, one of children health resorts, the contents of nine heavy metals, with a special focus on Cd, Pb and Zn, were determined in soils, grass, sands and dusts. The highest concentrations of Cd, Pb and Zn occur in soil samples: 2-3, 32-48 and 33-291 mg∙kg-1, respectively. Slightly lower are the concentrations in the sands taken from sandboxes: 1-3, 25-36 and 7-20 mg∙kg-1 of Cd, Pb and Zn, respectively. In the grass, commonly growing in playground areas, the average concentrations of the metals are: 1.8, 20 and 60 mg∙kg-1 of Cd, Pb and Zn, respectively. While the contents of the three metals in soils and sands do not exceed natural concentrations, the contents of Cd and Pb in grass exceed the values considered natural. The urban atmospheric dusts, suspected to be the major source of pollution, were analysed for the three metals. Their ranges (in mg∙kg-1) are: 6-15 for Cd, 80-215 for Pb and 104-260 for Zn. The lowest effects of pollution characterise the playground in the park no. III located in Orkana Street, whereas the highest the playground in the park no. I located in Parkowa Street. However, in none of the locations, the levels of Cd, Pb and Zn exceed the potentially harmful elements (PHE) considered as threatening the health and even life of children.

Lead in grass in the Scottish uplands: deposition or uptake?

If it is assumed that the Pb collected in grass samples is derived mainly from atmospheric deposition then grass samples can be used as a convenient and easily analysed monitor for Pb deposition, in particular to establish the isotopic composition of current deposition in remote locations. As some studies have demonstrated a strong correlation between soil and grass Pb concentrations, it was considered important to establish the proportion of soil Pb in the grasses used to monitor atmospheric deposition at upland locations in Scotland. Consideration of earlier studies provided evidence that very little, if any, Pb in grass was derived from soil. Lead isotope analysis, by thermal ionisation mass spectrometry, of grasses grown on soils spiked with enriched (207)Pb in the field situation allowed the relative contribution of atmospheric deposition and soil to the grass Pb to be calculated. In most cases, >80% of Pb in grass was derived from atmospheric deposition and in recent years this value was >90%. Recalculation of the (206)Pb/(207)Pb ratio in grass samples showed that there was very little error in the results, published previously, which were based on the assumption that all the Pb collected with grass was derived from the atmosphere. The trends established by measuring the (206)Pb/(207)Pb ratio in grasses were confirmed and remain valid.

Lead and cadmium interactions in Cynodon nlemfuensis and sandy soil subjected to treated wastewater application under greenhouse conditions

Pb and Cd are known to influence each other’s uptake by some plants when the two metals exist in the soil in significant amounts. This influence may be beneficial if it reduces uptake of metal by plants but may be detrimental if it increases uptake of the metal. This study was carried out to investigate the interaction of Pb and Cd in sandy soils and Cynodon nlemfluensis (star grass). Star grass was grown under greenhouse conditions in 33 fertilized pots containing sandy soils. Three weeks after planting the grass the pots were randomly assigned to the following treatments replicated three times; (a) application of three varying concentrations of Pb or Cd in addition to effluent and sludge, (b) application of three varying concentrations of combined Pb and Cd in addition to effluent and sludge, (c) application of water and (d) application of only effluent and sludge. Analysis of grass samples was done 45 and 90 days after addition of Pb and Cd to pots and that of the soil was done 90 days after addition of Pb and Cd to pots. The log normal mean level (in mg/kg) of Pb detected in the soil was 1.75 and that of Cd was 0.057 in mixed treatments while for single treatments the levels were 1.67 for Pb and 0.03 for Cd. The presence of Cd in the soil had no effect on the bio-available level of Pb but Pb significantly ( p < 0.05) increased the bio-available concentration of Cd. The log normal mean levels of Pb in grass re-growth from mixed treatment was 1.68 and that of Cd was 0.57 while the values for single treatments were 1.47 for Pb and 0.31 for Cd. There was no significant change in the level of uptake of Pb between single treatments and mixed treatments. However, Pb significantly increased uptake of Cd in mixed treatments compared to single treatments ( p < 0.05). The results of this study indicate that co-presence of Pb and Cd may have the detrimental effect of increasing uptake of Cd in star grass.

An assessment of lead pollution caused by vehicles emissions in a highly inhabited region of Sofia, Bulgaria

Lead concentrations have been determined in air, soil and vegetation samples taken along a major boulevard in Sofia town. Concentrations of total suspended particles (tsp) were also measured. The following concentrations have been found: tsp ‐ 0.168÷5–1.242 mg/m3; Pb aerosols ‐ 0.00058÷0.00573 mg/m3; Pb in soil ‐ 16.2÷184.3 mg/kg; Pb in grass ‐ 2.6÷27.4 mg/kg. Tsp concentrations as well as Pb concentrations in air, soil and vegetation correlated negatively with distance to the road. Airborne particle Pb is the main source for soil and vegetation pollution. Sequential extraction showed that Pb was bound predominately to CO3 2‐ and only in a small quantity to easily exchangeable phase, to iron and manganese oxides and to organic matter. The results showed that Pb concentrations in soìl meet the maximum permissible concentrations, except for the 5–10 meters adjacent to the road. However, a possibility exists for Pb accumulation in soil. Planting suitable vegetation and promoting use of unleaded fuel can be proposed as measures to be taken.

Monitoring of airborne metals in grass and depositions

Samples of standardized grass cultures and depositions collected according to BERGERHOFF revealed differing concentration gradients of Pb, Sb and Cd vs. distance to heavily traveled roads. Results suggest varying suitability of the methods with regard to indication of metal pollution. Bioaccumulation of Pb in grass (in terms of deposition plus incorporation) was moderate compared to Pb depositions. Bioaccumulation of Sb, however, showed stronger concentration gradients compared to Sb depositions. Positive correlations (r = 0.6 to 0.8) between deposition and grass contents of Pb and Sb were found. Pb and Sb contents in grass, sampled at roadside locations correlated significantly, too. It is being suggested that varying bioaccumulation mechanisms of the metals are due to their predominance on different sizes of particles and to their individual prevalence in a number of different metal compounds.