It is known that the search for new detection systems remains relevant. Recently, a new class of artificial ferments, so-called nanozymes has been proposed [1]. The prospects of using natural enzymes as detection systems are limited by their high cost and low operational properties. Overcoming these shortcomings became possible by the creation of artificial mimetics of enzymes – nanozymes. Nanozymes are nanomaterials with their own enzyme-like activity, they are able to combine both the catalytic properties of enzymes and the properties of nanoscale materials. Compared with natural enzymes, nanoferments have better stability, can be mass-produced at lower cost, their properties can be quickly developed and adapted to various requirements. Thanks to these advantages, they have demonstrated wide application in the monitoring and cleaning of the environment [2]. The presented report provides a comprehensive overview of nanozymes used in environmental analysis. Main attention is paid to the generalization of principles and methods for the determination of typical pollutants, including such as: toxic ions, pesticides, phenolic pollutants, antibiotic residues, hydrogen peroxide and pathogens. In particular, acid rains (pH <5.5) is currently a serious environmental problem worldwide. High acidity of rain occurs as a result of the oxidation reaction of H2O2 with dioxide and nitrogen oxides in the atmosphere. Thus, the concentration of H2O2 is an important indicator providing information about the environment. We have developed a colorimetric sensor with the property of peroxidase based on heterojunction. Determination of the hydrogen peroxide content in rainwater was carried out using a ZnFe2O4/ZnO film sensor manufactured by magnetron sputtering, Fig.1. The minimum detectable concentration of hydrogen peroxide in rainwater was 0.02 μM Fig.1. Peroxidase activity of the ZnFe2O4/ZnO film heterojunction and the mechanism of the color oxidation reaction of TMB.