Trace metals accumulation in the eco-system water - soil - vegetation (Agropyron cristatum) - common voles (Microtus arvalis) - parasites (Hymenolepis diminuta) in Radnevo region, Bulgaria.

BACKGROUND: Coal and coal processing industries provoke trace metal pollution, which has a negative effect on the water - soil - vegetation - small mammals eco-system, constituting part of the food chain and exerting a serious impact on human health. OBJECTIVES: Assessment of the environmental impact of Maritza iztok coal complex, situated east of Radnevo town, Bulgaria, by tracking the dynamics and accumulation of trace metals in the eco-system water - soil - vegetation - common voles - parasites. METHODS: Samples from surface waters, their nearby uncultivated soils, meadow uncultivated vegetation (Agropyron cristatum) and field common voles (Microtus arvalis) were collected. In situ measurements and laboratory extraction procedures and analyses were performed. Accumulation and mobility indices were calculated. The distribution of dissolved Mn, Ni, Cu, Zn and Pb chemical species in water-soil extracts was calculated using a thermodynamic approach. Two thermodynamic models were applied - the classical ion-association model for calculating the inorganic trace metal species and the Stockholm Humic Model (SHM) accounting for the complexation reactions of trace metals with organic matter. Visual Minteq computer program, Version 3.1 was used. The relationship chemical species - bioaccumulation was discussed. RESULTS: Pb and Mn, together with SO42- and PO43- were found to be the main pollutants of waters in the region. The soils studied exhibited low concentrations of trace metals, not exceeding the specified MACs. The content of Mn was the highest, followed by Zn, Pb, Cu and Ni. The highest phytoaccumulation coefficients in the studied uncultivated grass vegetation were calculated for Cu and Zn, being 1-2 orders of magnitude higher than those of Mn and Ni. The accumulation of trace metals was explained on the basis of ions mobility and chemical species distribution. In the case of the host-parasite system Microtus alvaris - Hymenolepis diminuta, Zn displays the highest accumulation coefficient, followed by those of Cu and Pb. The parasite showed a higher bioaccumulation compared to infected common voles, with the highest bioaccumulation found for Ni. CONCLUSIONS: The bioaccumulation of trace metals depends on their mobility, concentration and chemical forms in water-soil solutions. Metal-organic species stimulate the phytoaccumulation of trace metals while inorganic ones suppress it. The sequence of trace metals bioaccumulation in common voles is analogous to that of soil contamination. The parasite exhibited higher bioaccumulation levels compared to infected common voles.

Dynamics of trace metals in the system water - soil - plant - wild rats - tapeworms (Hymenolepis diminuta) in Maglizh area, Bulgaria.

BACKGROUND: The impact of chemical elements on the biosphere is a function of their concentration and chemical form. Elucidation and prognosing of the latters in water basins and soil extracts is of particular significance for the assessment of their bioaccumulation in plants and animals. OBJECTIVES: Trace metals dynamics in the system water - soil-plant-wild rats - Hymenolepis diminuta in two agro-industrial zones (East and West) around Maglizh city, Bulgaria were investigated through experimental studies and thermodynamic modelling of the chemical species. METHODS: Samples from surface waters of rivers, their nearby uncultivated soils, meadow uncultivated vegetation (Ranunculus acris and Gramineae) and field rats were collected. In situ measurements and laboratory analyses were performed for the determination of the physico-chemical characteristics and total concentrations of Al, Fe, Mn, Ni, Cu, Zn and Pb. The distribution of their dissolved chemical species in water samples and in the aqueous soil extracts was calculated using a thermodynamic approach. The relationship chemical species - bioaccumulation was discussed. RESULTS: Waters and soils in the East zone of Maglizh area were found to be more polluted compared to those in the West one, regarding Ni, Mn, Zn, Pb and Cu, while Mn and Cu displayed the highest mobility in West zone soils. Trace metals contents in Ranunculus acris exceed that in Gramineae, since the highest accumulation factors were calculated for Cu and Zn. The highest accumulation in rats was found for Zn followed by Cu, being higher in the West zone. Thermodynamic modelling shows that Mn2+ free ions are dominant in both waters and aqueous soil extracts. Ni2+ and Zn2+ ions followed by metal-organic complexes are dominant in waters of East zone while metal-organic complexes followed by free ions are dominant in waters of West zone and both soil extracts. Metal-organic complexes are dominant for Fe, Cu and Pb in all samples studied, while mainly hydroxy forms (Al(OH)4-) followed by metal-organic complexes are typically for Al depending on pH. CONCLUSIONS: Experimentally established bioaccumulation of trace metals in the studied vegetation and rats is a consequence of the total concentration of trace metals in waters and soils, their mobility and chemical species. The dominance of organic complexes of trace metals is a prerequisite for their bioaccumulation in plants. Rats are in direct contact with the soil solution and therefore, of importance is the content of free ions of Mn2+, Ni2+, Zn2+, which are easily absorbed through the skin. The host-helminth system wild rat/H. diminuta could be used as a bioindicator for trace metals pollution.

Anthelmintic efficacy of Moringa oleifera seed methanolic extract against Fasciola hepatica.

The current study was carried out to assess in vitro and in vivo effects of Moringa oleifera seed methanolic extract on Fasciola hepatica to develop an alternative source of treatment. The in vitro ovicidal effect of M. oleifera seed extract on immature F. hepatica eggs has provided evidence of inhibitory activity on the vitality and hatchability of F. hepatica eggs. This inhibitory activity was concentration-dependent and also correlated strongly with the exposure time. In the in vivo trial, the oral administration of F. hepatica experimentally infected rabbits with doses of 150 mg/kg BW prepared extract per day for 3 consecutive days on the 63rd day post infection confirmed potent fasciolicide activity of the extract. A gradual decrease in fecal egg count (FEC) was detected from the 1st day post treatment until reaching 100% FEC reduction by the 7th day post treatment. No flukes could be found at post mortem examinations. Significant increments of serum total protein, globulin, the activities of ALT and AST, total cholesterol, triglycerides and urea were recorded during the period of infection, which were improved by treatment. Remarkable histopathological alterations were observed in the infected liver and gallbladder tissues which decreased clearly in the treated rabbits. This study proposes that the used extract has promising and potent fasciolicide activity.

Evaluation of different Haemonchus contortus antigens for diagnosis of sheep haemonchosis by ELISA and their cross reactivity with other helminthes.

Haemonchus contortus (H. contortus) remains important nematode that infecting sheep all over the world. Truthful diagnosis of haemonchosis needs reliable Enzyme linked immune sorbent assay test as well as the immuno-reactive protein profile of different prepared H. contortus antigens; larval (L), excretory secretory product (ESP) and adult somatic H. contortus (AS). The current study fulfilled that L antigen is the talented antigen for such serological diagnosis. Immunodominant band at molecular weight 57 kDa were answerable for highest specificity and accuracy of positive predictive value of this antigen. Moreover, the highest apparent prevalence value was 92 and 75% obtained by L and ESP antigens, respectively. The results of cross reactivity among AS, Monezia expansa (M. expansa) and Fasciola spp. revealed that AS antigen appeared major cross reactivity with other cestode and trematode. Best dilution of serum was (1:800) to rise above this phenomenon.