Presence of natural radionuclides and toxic elements in monocalcium phosphate, complete feed and pig manure.

Naturally occurring radionuclides and toxic elements are ubiquitous in the environment and can pose a great risk to animals' health. Control of these toxic substances in animal diet is essential for animal's welfare, human nutrition risk management as well as environmental protection. Our study addresses these issues by determining a content of natural radionuclides (40K, 238U and 226Ra), and toxic elements (Cd, Cr, As) in total of 108 samples: 36 monocalcium phosphate, 36 complete feed and 36 pig manure samples that were collected from 6 different commercial farms in the Republic of Serbia. In monocalcium phosphate the content of 40K, 238U and 226Ra ranged from 7.6-23.4 Bq kg-1, 13.2-1778 Bq kg-1 and 3.6-13.5 Bq kg-1, respectively. In complete feed samples, 40K ranged from 170 to 306 Bq kg-1, 238U from minimum detectable activity (MDA) to 9.1 Bq kg-1, and 226Ra from MDA-5.5 Bq kg-1, while in pig manure 40K ranged from 146 to 531 Bq kg-1, 238U from MDA-30.1 Bq kg-1, and 226Ra from MDA-10 Bq kg-1. The concentrations of Cd, Cr and As in monocalcium phosphate were 0.26-14.9 mg kg-1, 10.3-497 mg kg-1, and 4.2-5.5 mg kg-1, respectively. In complete feed, the content of Cd, Cr and As ranged from minimum detectable concentration (MDC) - 0.78 mg kg-1, 0.30-7.41 mg kg-1, and 0.09-0.31 mg kg-1, respectively. In pig manure Cd, Cr and As ranged from 0.8-2.3 mg kg-1, 2.3-22.2 mg kg-1, and 0.51-5.45 mg kg-1, respectively. The obtained results showed that Cd concentration in monocalcium phosphate exceeded the maximum permissible legislative concentrations for phosphate additives. Monocalcium phosphate is the main source of 238U and Cr in complete feed, while Cd derives from other sources. For that reason excessive use of monocalcium phosphate can lead to high levels of these pollutants in complete feed and consequently in manure.

Toxicity of high uranium doses in broilers and protection with mineral adsorbents.

The aim of this study was to determine the uranium distribution and histopathological changes in broiler organs (kidney, liver, and brain) and muscle after 7 days of contamination with high doses of uranyl nitrate hexahydrate (UN), and the protective efficiency of three different mineral adsorbents (organobentonite, organozeolite, and sepiolite). During the 7 days, the UN administration was 50 mg per day, and administration of adsorbents was 2 g per day immediately after UN. In control group where broilers received only UN, histopathological changes such as necrosis of intestinal villi, oedema, vacuolisation and abruption of epithelial cells in renal tubules, oedema and vacuolisation of the cytoplasm of hepatocytes, and dystrophic changes in the neurons of the medulla oblongata were observed. In contrast, when the adsorbents organobentonite, organozeolite, and sepiolite were administered, no histopathological changes were observed in liver and brain. The investigated adsorbents showed the highest protective effects in liver (80-92%), compared to the kidney (77-86%), brain (37-64%), and meat (31-63%).

Natural and anthropogenic radioactivity in the environment of Kopaonik mountain, Serbia.

To evaluate the state of the environment in Kopaonik, a mountain in Serbia, the activity concentrations of (4) K, (226)Ra, (232)Th and (137)Cs in five different types of environmental samples are determined by gamma ray spectrometry, and radiological hazard due to terrestrial radionuclides is calculated. The mean activity concentrations of natural radionuclides in the soil are higher than the global average. However, with an exception of two sampling locations, the external radiation hazard index is below one, implying an insignificant radiation hazard. Apart from (40)K, content of the natural radionuclides is predominantly below minimum detectable activities in grass and cow milk, but not in mosses. Although (137)Cs is present in the soil, grass, mosses and herbal plants, its specific activity in cow milk is below minimum detectable activity. Amongst the investigated herbal plants, Vaccinium myrtillus L. shows accumulating properties, as a high content of (137)Cs is detected therein. Therefore, moderation is advised in consuming Vaccinium myrtillus L. tea.