Effect of Sorbent Additives to Copper-Contaminated Soils on Seed Germination and Early Growth of Grass Seedlings.

Heavy metal and metalloid-contaminated soil is a serious barrier to colonization for many plant species. The problem of the elimination of toxic waste accumulated in technogenous soils in many highly transformed regions is extremely important. Hence, another attempt was made to analyze the effect of the addition of sorbents (BCH-biochar, B-bentonite, ChM-chicken manure, OS-organo-zeolitic substrate) to contaminated copper soil on the germination and early growth of Eurasian common grass species (Agrostis capillaris, A. stolonifera, Festuca rubra and Poa pratensis), which could potentially be used in recultivation. This experiment was based on the laboratory sandwich method. Standard germination indexes, morphometry and biomass analysis were used. The percentage of germinating seeds was lower in each of the soil variants and sorbents used compared to the control. Dry mass was positively stimulated by all sorbents. The response to the addition of sorbents, expressed as the electrolyte leakage of seedlings, was different depending on the species and type of sorbent. Among all sorbents, the most positive effects on germination and growth were observed in the case of OS. Overall, the response to the addition of sorbents was different in the studied species, depending on their stage of development.

Effects of Natural Sorbents on the Germination and Early Growth of Grasses on Soils Contaminated by Potentially Toxic Elements.

The reclamation of abandoned mining heaps rich in potentially toxic elements (PTEs) is critical for the environment. We carried out a laboratory experiment studying the effects of the addition of four natural sorbents (biochar, bentonite, chicken manure and organo-zeolitic substrate) to soils contaminated with PTEs, predominantly Cu, As and Sb, on the germination and growth of the autochthonous grasses Agrostis capillaris, A. stolonifera, Festuca rubra and Poa pratensis. The experiment used Petri dish tests with water extracts of contaminated soil and soil neutralised with the four sorbents. Standard indexes of the germination process were used (germination percentage, time required for 50% germination index, speed of emergence), and different values were found depending on the plant species and sorbent used. However, the percentage of seeds germinating was lower for each sorbent compared to the control (distilled water). The fresh mass values were positively stimulated by all sorbents. Electrolyte leakage was the highest in seedlings watered with an extract of untreated soil from the heap compared to extracts from treated soils and the control. This can be interpreted as eliminating the harmful effects of increased potentially toxic element (PTE) contents by sorbents, which can be useful in remediation processes.