Heavy metal characteristics in Ko?ani Field plant system (Republic of Macedonia)

Heavy metal contamination of soils is widespread and induces a long-term risk to ecosystem health. This research focuses on the heavy metal contamination, transfer values and risk assessment in the Ko?ani Field plant system (Republic of Macedonia). To identify the heavy metal concentrations in Ko?ani crops (rice and maize), the geochemical analysis was performed by inductive coupled plasma mass spectrometer and thereupon the transfer factor (TF) and estimated daily intake amount values were calculated. The highest As, Cd, Mo, Pb and Zn values were determined in the rice samples grown in the paddy fields near the Zletovska River. The highest Pb and Mo concentrations measured in the maize samples were from the maize fields near the Zletovska River and Ciflik city. High TF values for Mo, Zn, Cd and Cu revealed a strong accumulation of Mo, Zn and Cd by rice and Mo and Zn by maize crops. The results of the estimated daily intake showed that the regular consumption of rice and maize crops containing the highest Cd, Mo, Pb and Zn concentrations could pose a serious threat to human health, because the daily intake of Cd, Mo, Pb and Zn for crops grown in the fields around the Zletovska River exceeded the recommended provisional tolerable daily intake values. Taking into account the results, the area around Zletovska River is considered as the most anthropogenically impacted part of Ko?ani Field.     

Heavy metal contamination of paddy soils and rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) from Kočani Field (Macedonia)

This research focuses on the heavy metal contamination of the paddy soils and rice from Kočani Field (eastern Macedonia) resulting from irrigation by riverine water impacted by past and present base-metal mining activities and acid mine drainage. Very high concentrations of As, Cd, Cu, Pb and Zn were found in the paddy soils (47.6, 6.4, 99, 983 and 1,245 μg g⁻¹) and the rice (0.53, 0.31, 5.8, 0.5 and 67 μg g⁻¹) in the western part of Kočani Field, close to the Zletovska River, which drains the mining facilities of the Pb–Zn mine in Zletovo. In terms of health risk, the observed highest concentrations of these elements in the rice could have an effect on human health and should be the subject of further investigations.     

Major and trace elements in paddy soil contaminated by Pb–Zn mining: a case study of Kočani Field,Macedonia

The objective of this study was to assess the bulk chemical composition as well as the extent and severity of heavy metal contamination in the paddy soil of Kočani Field (eastern Macedonia). The results revealed that the paddy soil of the western part of Kočani Field is severely contaminated with Pb, Zn, As and Cd in the vicinity of the Zletovska River due to irrigation with riverine water that is severely affected by acid mine and tailing effluents from the Pb–Zn mine in Zletovo. The detected total concentrations of these metals are far above the threshold values considered to be phytotoxically excessive for surface soil. The paddy soil in the vicinity of the Zletovska River was also found to exhibit elevated levels of Ba, Th, U, V, W, Mo, Cu, Sb, Bi, Ag, Au, Hg and Tl, with concentrations above their generally accepted median concentration values obtained during this study. A correlation matrix revealed that the Mn and Fe oxides/hydroxides are the most important carrier phase for several trace elements, with the exception of rare earth elements (REEs). These also represent a major sink for the observed heavy metal pollution of the soil. REEs are mostly associated with two phases: light (L)REEs are bound to K-Al, while heavy (H)REEs are bound to Mg-bearing minerals. Although there is no direct evidence of a health risk, the paddy soil in the vicinity of Zletovska River needs further investigation and an assessment should be made of its suitability for agricultural use, particularly in view of the highly elevated concentrations of Pb, Zn, As and Cd.     

Phytoremediation of landfill leachate and compost wastewater by irrigation of Populus and Salix: Biomass and growth response

A pot experiment is described with a fast-growing poplar clone and two native willows (Populus deltoides Bartr. cl. I-69/55 (Lux)), Salix viminalis L. and Salix purpurea L.), irrigated with landfill leachate and compost wastewater over a 1-year growing period. The use of leachate resulted in up to 155% increased aboveground biomass compared to control water treatments and in up to 28% reduced aboveground biomass compared to a complete nutrient solution. The use of compost wastewater resulted in up to 62% reduced aboveground biomass compared to the control treatments and in up to 86% reduced aboveground biomass compared to the complete nutrient solution. Populus was the most effective in biomass production due to the highest leaf production, whereas S. purpurea was the least effective in biomass accumulation, but less sensitive to high ionic strength of the irrigation water compared to S. viminalis. The results showed a high potential for landfill leachate application (with up to 2144 kg N ha^?1, 144 kg P ha^?1, 709 kg K ha^?1, 1010 kg Cl ha^?1, and 1678 kg Na ha^?1 average mass load in the experiment). High-strength compost wastewater demonstrated less potential for application as irrigation and fertilization source even in high water-diluted treatments (1:8 by volume).