Comparing levels of certain heavy metals and minerals and antioxidativemetabolism in cows raised near and away from highways*

Abstract

IntroductionHeavy metals are elements with a density higher than 5 g/cm 3 or with an atomic weight larger than 50 (1). Heavy metals are known to be chemicals extremely dangerous to living organisms. Large quantities of heavy metals are discharged each day in various ways and reach the rivers, lakes, and seas (2).Environment and soil in which the food consumed was grown and water involved in the cultivation are of importance regarding the intake of these metals. Tissue damage or even mortality might occur as a result of heavy metal accumulation in the biological tissues such as liver, kidney, and brain and body fluids of animals that are fed on plants grown in soils with dense industrial pollution and vehicle traffic (1,2).Currently, it is known that heavy metal ions lead to serious health problems; they even cause death in some cases. Therefore, it is important to focus on heavy metal contamination, and it is necessary to examine various sources and concentrations of heavy metals in foods and to take effective precautions (3). Heavy metals, most of which are necessary for organisms, bind to cell structure in very low concentrations. However, higher concentrations of these heavy metals might produce toxic effects by inhibition of enzyme systems in organisms. Mercury (Hg), lead (Pb), cadmium (Cd), and copper (Cu), in particular, have greater toxicity (4,5).Factors that affect the degree of heavy metal toxicity include the form of the metal, the presence of other metals and poisons, environmental factors (pH, temperature, oxygen, etc.), life-stage and sex of the organism, etc. (6). While some metals such as arsenic (As), Cd, Hg, molybdenum (Mo), Pb, and selenium (Se) are extremely toxic, some of them have carcinogenic [As, Cd, chromium (Cr), nickel (Ni), Pb, Se], mutagenic, and teratogenic effects. In addition, Cd stimulates free radical production by oxidative deterioration of lipids and Pb may lead to damage as a result of disruption of the equilibrium between oxidants and antioxidants in mammalian cells (7).

Impact of the copper industry on the content of selected heavy metals and biochemical indicators in the blood of dairy cows

“…TAS i GR. Pewne zależności między metalami ciężkimi a wybranymi wskaźnikami biochemicznymi u bydła są zbadane, dotyczą głównie wpływu Cd i Pb (18,29,32,45).…”

“…Aktywność enzymów w surowicy krwi zależy w dużym stopniu od stanu fizjologicznego zwierząt, w tym stanów chorobowych, diety (żywienia), a także czynników środowiskowych, w tym obecności substancji toksycznych (18,41,42,45). Uzyskane wyniki wskazują na pewne różnice między rejonami badań (tab.…”

“…Z dostępnej literatury (1,18,48) wynika, że system utrzymania, pora roku, poziom laktacji czy nawet stan zdrowotny wywierają na ogół niewielki wpływ na koncentrację makroelementów w surowicy krwi krów. Wydaje się, że koncentracja głównych makroskładników w surowicy może ulegać niekorzystnym fizjologicznie zmianom, gdy niezbilansowany jest poziom żywienia mineralnego, np.…”