Bioassay of Humic Products as Potential Remedies: A Review

Experimentally substantiated assessment of the remediation properties of humic products is an important condition for their safe and effective use. The review provides an analysis of existing approaches to biotesting of humic products, which enable us to draw a conclusion about the efficiency of detoxification of soils and adjacent media and about ensuring the viability of biocenoses, when using humic products. The advantages and disadvantages of traditional approaches to biotesting of humic products in soil media based on well-known reactions of higher plants and microorganisms, as well as the possibility of algotesting, using fluorescent methods, and mycotesting of humic products in aqueous and artificial nutrient media are discussed. The results of the experimental verification of the remediating ability of humic products during biotesting in media rich in organic substances indicate the need to standardize the conditions for the quantitative assessment of the quality of humic products. Standard artificial soil (according to ISO 11268-2) may be used as a universal soil matrix for the initial assessment of humic products. To summarize their quality as potential soil improvers, the proposed remediation index is calculated by the data of chemical, bioindication, and ecotoxicological studies of soil treated with humic products.