The total and available (water extracted) content of selected metal were determined in co-pyrolyzed SSL with willow (8:2, 6:2 w/w) at 500, 600, and 700 °C using two different carrier gases (N₂ or CO₂). The study investigated the relationship of metal content and bioavailability to toxicity of biochars towards bacteria (Vibrio fischeri), plants (Lepidium sativum), and arthropods (Folsomia candida). For the biochar produced at a ratio of 6:4 (SSL:willow), the content of most metals significant decrease (P ≤ 0.05) from 5.9% to 28.9%. Co-pyrolysis of SSL with willow decreased water extractable metal concentrations (Ba, Cd, Cu, Fe, Mn, Ni, and Zn) from 8.0% to 100%. The CO₂ resulted from 6 to 200 % increase (P ≤ 0.05) of metal content relative to the biochar pyrolyzed in N₂. An increase in pyrolysis temperature caused a higher concentration of the metals in the biochars. The available content of most metals decreased from 9 to 100 %. The adverse effect of these biochars on living organisms was reduced due to a stronger binding of the metals (especially Cu and Cd) with the biochar matrix. The negative impact of Cd, Cr, and Cu on living organisms was also confirmed by principal component analysis (PCA).

Phthalic acid esters (PAEs) are dialkyl or alkyl/aryl ester derivatives of phthalic acid. PAEs are colorless, odorless, and flavorless oily liquids. PAEs are the main plasticizers used in industry and households. DEHP (di-(2-ethyl hexyl) phthalate) is the main plasticizer used in the polymer industry, whereas DMP (dimethyl phthalate) and DEP (diethyl phthalate) are used mainly as solvents or fixatives in cosmetics and personal care products. PAEs are synthetic organic compounds poorly soluble in water but soluble in organic solvents. Into the environment, they are introduced during the production, use and degradation, packaging, and transportation of plastic products. In the environment, PAEs are degraded in three ways: by hydrolysis, photodegradation, and microbial degradation, whereas the biodegradation and hydrolysis of PAEs in the environment are very slow. PAEs are pollutants of soil, water, groundwater, river water, marine water, air, sediments, vegetables, and biota. Due to the great interest in the subject of environmental pollution by PAEs and the emergence of new information in this area, it is extremely important to systematically review the current knowledge. In the presented paper, the occurrence of PAEs in different environmental matrices was reviewed. The toxicity to plants, animals, and humans was also described.