The status of heavy metals in arable soils of contrasting texture treated by biochar - an experiment from Slovakia.

Worldwide, many soils are impacted by degradation processes, which impose a risk to sustainable food production. There is a pressing need to limit these negative impact constraints to sustain the proper functioning of the soil-biota system and soil productivity. Biochar can be a nature-friendly solution for soil remediation; however, knowledge is incomplete in many aspects in this field, like the potential of biochar and biochar-based products as agents to immobilize toxic substances, including heavy metals (HMs) found in the soil. In this study, we investigated the effect of two biochar substrates (BSs) (1. biochar blended with farmyard manure as BS1, and 2. biochar blended with farmyard manure and digestate as BS2) at rates of 10 and 20 t ha-1 applied without or with fertilization (BS + F) on the immobilization of HMs in texturally different soils (1. sandy Arenosol, 2. loamy Chernozem, Slovakia). The results showed that application of BS had different effects in relation to soil textures. In sandy soil, BS improved soil properties, such as cation exchange capacity (an increase from 20 to 93%), soil organic carbon content (SOC) (an increase from 3 to 26%) and humic substances (HSs) stability (an increase from 12 to 20%). In loamy soil, SOC increased due to BS and BS + F in the range 3-19% and 12-55%, respectively. In both soils, the total content of HMs did not exceed the threshold limits for individual soils after BS and BS + F application. In sandy soil, the immobilization of HMs was due to a higher SOC content and a fulvic acids (FAs) content, while in loamy soil their elimination depended on a higher available phosphorus content.

Phytofiltration of chosen metals by aquarium liverwort (Monosoleum tenerum).

Aquatic bryophytes are widely used as indicators of water pollution with various substances, including metals. We present a first study concerning the feasibility of Monosoleum tenerum to remove potentially toxic metals Zn, Cu, Ni, Mn and Fe from water. The novel approach to study the bioaccumulation under controlled conditions and in vitro grown aquarium liverworts was applied. The plants were exposed to 1, 10 and 100 ppm multi-metal solution for 7 days and subsequently the metal content was determined in plant material and media to calculate the bioaccumulation factor (BAF). The study revealed various accumulation behavior (metal and dose dependent), which followed the order of Cu > Zn > Mn > Ni > Fe for 1 ppm; Zn > Cu > Mn > Fe > Ni for 10 ppm and Cu > Fe > Zn > Ni > Mn for 100 ppm solution. However, with increasing Cu, Mn and Ni concentration in the solution, BAF decreased. For Zn the highest BAF value (136) was obtained for the 10 ppm solution. Fe bioaccumulation increased with the increasing solution concentration. After 7 week exposure, the results indicated highest accumulation of Cu (3,25 mg) followed by Fe (1,8 mg) in the plant tissue for the 100 ppm solution. Overall, the bryophyte M. tenerum demonstrate high potential for the removal of toxic metals from the multi-metal solution via accumulation in plant tissue. The BAF values were proper to indicate the use of M. tenerum for phytofiltration of waste waters affected by Zn, Cu, Ni, Mn and Fe.

Accumulation of airborne potentially toxic elements in Pinus sylvestris L. bark collected in three Central European medium-sized cities.

This study attempts to identify the influence of various aspects of human activities in three medium-sized Central European cities (Cottbus, Germany; Nitra, Slovakia and Slupsk, Poland) on air contamination. For comparison purposes, bark of Pinus sylvestris L. was collected from polluted and non-polluted urban areas. Nine elements: Fe, Mn, Cu, Zn, Ni, Cd, Cr, Pb and S were determined using microwave plasma atomic emission spectrometry, flame atomic absorption spectrometry and elementary analyzer. Results of the study showed significant differences between the cities in term of elements content in pine bark. The differences reflected well specific character of the cities and various effects of human activity. Study revealed that elements spatial variability among the cities is driven by the factor loadings character and reflects various emission sources and their impact range.