Evaluation of physical properties and heavy metal composition of manure of some domestic animals

Abstract

Heavy metal content in animal manure could influence soil quality, contaminate crops and cause health risks to both livestock and humans. The objective of this study was to evaluate the physical properties and heavy metal composition of manure of some domestic animals. Manure samples were collected from six domestic animals (goat, cow, donkey, pig, turkey and layer chickens). Standardized protocols were followed for sample preparation and analysis of heavy metal content. The physical properties (physical appearance, moisture content and organic matter) of the samples were observed and recorded. The metals measured were Calcium (Ca), Magnesium (Mg), Iron (Fe), Manganese (Mn), Zinc (Zn), Lead (Pb), Copper (Cu), Cadmium (Cd) and Nickel (Ni). Concentrations of heavy metals were measured using flame atomic absorption spectrometry (FAAS). The results showed that donkey manure had the lowest Zn, Cu, Pb, Ni and Mg contents. Pig manure had the highest Fe content as well as the lowest Mn, Cd and Ca contents. It is recommended that manure of farm animals be cautiously examined for heavy metal content before its application to the soils of agricultural farms or fields.