Regularities of accumulation of heavy metals by strawberry (Fragaria×Ananassa Duch.) plants from soddy-podzoly soil using adsorbents based on mineral and polymeric substances

Abstract

In vegetative experiment has been studied the infl uence of adsorbents on the basis of mineral and polymer substrates Bentonite, Arpolit, Supradit, Agronit on the accumulation of heavy metals (HM) of strawberry plants plant variety Troitskaya in the artificial contamination of sod-podzolic soil at the level MAC (maximum allowable concentration) of total content of TM: Cd 2 mg/kg, Cr 100 mg/kg (MAC missing), Pb 130 mg/kg, Zn 220 mg/ kg. It was found that the use of adsorbents based on mineral and polymer substrates helps to reduce the content of mobile forms of Cr, Cd, Pb in the soil. Their content is reduced to the greatest extent when the adsorbents Supradit M are added to the soil (by 78.5 % for Cd and 40.1 % for Pb, compared with the control) and Agronite (by 79.0 % for Cd and 48.9 % for Pb, compared with the control). For mobile Cr, the downward trend in soil content was statistically unreliable. The content of mobile Zn in the variants with all adsorbents, on the contrary, increased in comparison with the contaminated control, to the greatest extent when the adsorbent Supradit M was added – by 26.1 %, compared with the control. The use of adsorbents led to a decrease in the content of Cd and Pb in the roots of strawberry plants. The greatest decrease in their content in the roots was when adding adsorbents Supradit M (65.2 % for cadmium and 76.8 % for lead, compared with the control) and Agronite (65.7 % for cadmium and 78.2 % for lead, compared with the control). The content of Zn in the roots in the variants with the introduction of adsorbents, except for Bentonite, increased in comparison with the contaminated control, to the greatest extent with the introduction of the adsorbent Supradit M – by 45.2 %. The content of Cr in the roots when using all adsorbents, except Agronite, also tended to increase, to the greatest extent when applying Arpolite – by 105.9 %, compared with the control. When applying the adsorbents Supradit M and Agronit to the soil, the content of Cd in the leaves decreased: when applying the adsorbent Supradit M by 52.9 %, Agronit – by 41.2 %, compared to the control. The content of Zn, Cr, and Pb in the leaves in the variants with adsorbents increased in comparison with the contaminated control, to the greatest extent when adding the adsorbent Arpolite: by 63.7 % – for Zn, by 71.2 % – for Cr, and by 46.3 % – for Pb. When using this adsorbent, the content of Cd in the leaves also increased – by 105.9 % higher than the contaminated control. The content of Cd, Cr, Pb, Zn in the berries of strawberry when using adsorbents less than in the roots and leaves, depended on the content of the corresponding heavy metals in the soil and was not statistically significant. When adding the adsorbents Supradit M and Agronit to the soil, the content of Cd in berries tended to decrease: when using the adsorbent Supradit M – by 30.0 %, Agronit – by 40.0 %, compared with the control. When adding the adsorbent Arpolite to the soil, the Cd content in berries tended to increase by 30.0 %, Pb – by 111.8 % from the control. The Cr content in the berries in the variants with adsorbents increased in comparison with the contaminated control, to the greatest extent with the introduction of Bentonite adsorbent – by 180.0 %. For the content of Zn in berries, there was no pronounced natural tendency for adsorbents to act. The closest relationship between the content of TM in the organs of strawberry plants and the content of mobile forms of heavy metals in the soil was observed for roots and leaves. There was no such dependency for Cr. At the studied levels of mobile TM content in the soil, the barrier properties of strawberry plants play an important role in the accumulation of heavy metals. The translocation coefficients of heavy metals were higher in the experiment variants, in which a decrease in the content of mobile forms of TM in the soil was observed when adding adsorbents. For Cd in the variant using the adsorbents Supradit M and Agronit, the TM translocation coefficients were higher than the control value by 98.0 and 72.5 %, respectively. For Pb, the values of translocation coefficients increased with the use of these adsorbents, compared to the control, by 300 % and 350 %, respectively. With an increased content of mobile forms of TM in the soil in the variants with the introduction of adsorbents Supradit M and Agronit, the translocation coefficients for Zn, compared to the control, were lower by 33.3 % and 33.3 %, respectively.