Assessment of the risk of contamination by heavy metals and correlation analysis of the content of toxicants in animal feed and organic waste

Abstract

Pollution of agroecosystems by heavy metals posesa signifcant threat to agricultural production in various countries of the world, including Ukraine. In the postwar period, the environmental situation will be even more complicated. Timely assessment of environmental risk using the results of laboratory analysis of the feed of dairy cows and their organic waste for the content of ecotoxicants such as cadmium and lead obtained in scientific experiments is important. Correlation analysis is one of the methods of statistical data processing that, when properly applied using modern computer software, allows you to quickly establish the strength of the relationship between indicators and its statistical signifcance. Such research methods are used by scientists from the countries of the European Union, the USA, China, and other countries. Previous studies have focused directly on the concentrations of contamination with heavy metals Cd, Pb, and other animal feed and organic waste, but have not investigated the relationship between them. Scientifc and economic experiments were conducted on dairy cows with different types of feeding. The animals were selected by the method of analogues for live weight and productivity. The diet included feed with an excess of cadmium and lead. The high biological activity of pollutants influenced their transition from ration fodder to products and organic waste. The aim of the research was to analyze the correlation dependence between the content of Cd and Pb in cow feed and their organic waste with an assessment of the risk of soil contamination by hazardous toxicants in the area of activity of agro-enterprises producing milk after the introduction of organic waste as organic fertilizer. With the help of the STATISTICA version 10.0 computer program, the Shapiro-Wilk's W test, the conformity of the obtained data of laboratory analyzes of feed and organic waste with the concentration of heavy metals, the law of "normal" distribution (Gaussian), and then the non-parametric Spearman rank correlation coefcient necessary in this case is selected for calculation. The analysis established a high r=0.66-0.75 (Cd) (р<0.05), r=0.66-0.77 (Pb) (р<0.05) and a very high r=0.83 (Cd) (р<0.05), r=0.83 (Pb) (р<0.05) correlation dependence between the content of toxicants in feed and organic waste, which allows specialists to act quickly and efectively in production conditions, confdently use the method of environmental monitoring, forecast the environmental situation, assessenvironmental risks, including those related to organic and biological farming and avoid disturbing the ecological balance of agroecosystems. Further research is aimed at correlational and regression analysis, but on other important indicators of environmental safety in veterinary, zootechnical and ecological practice, with an assessment of the relevant risks of running the livestock industry in the forest-steppe zone of Ukraine. Key words: feed, organic waste, organic fertilizers, heavy metals, cadmium, lead, correlation, ecological risk, dairy cows.