Excretion of Dietary Zinc in Mammals (rats) Fed Overdoses of Zinc Lactate and Infected with Tapeworms.

Tapeworms parasitize at sites that are important for the management of micronutrients, including zinc. Therefore, it has been hypothesized that tapeworms will significantly affect the excretion of zinc in the feces of a host. The aim of this work was to evaluate the effects that tapeworms have on the excretion of zinc in the feces of the host. Rats were divided into 4 groups: groups 0T and MT (infected with Hymenolepis diminuta (Rudolphi, 1819)) and groups 00 and M0 (uninfected). The experimental groups (M0 and MT) were fed a standard rodent compound feed (ST-1) with added zinc lactate; the daily zinc intake was 20.5 mg. The control groups (00 and 0T) were fed only ST-1 with 1.75 mg of added Zn per day. For six weeks, the amount of consumed feed was recorded and fecal samples were taken. The samples were then analyzed by optical emission spectrometry (ICP-OES), and levels of excreted zinc were subsequently calculated as a percentage. The most signifi cant difference in zinc excretion levels between the experimental groups was observed in the third week, when rats infected with tapeworms (MT) excreted substantially lower levels of zinc than did uninfected rats (M0). This difference amounted to 28.36 % (p <0.01). In the control groups, tapeworms affected the excretion of zinc in the feces to a lesser extent, and the most substantial difference in zinc levels was seen in the fifth week (8.46 %). However, there was no signifi cant difference in zinc excretion levels between the control groups during any of the monitored weeks. Tapeworms in the host affect levels of zinc excreted in the feces. However, this is dependent on the amount or form of zinc ingested.

The effect of zinc and/or vitamin E supplementation on biochemical parameters of selenium-overdosed rats.

The normotensive (Wistar) and spontaneously hypertensive (SHR) rats were examined to assess the response of the organism to selenium (Se) overdose. Moreover, the effect of zinc (Zn) and vitamin E, i.e. dietary components interacting in many biochemical processes with Se, on the Se uptake was evaluated. The control group was fed an untreated diet, and the diets of two other groups were overdosed with Se in the form of sodium selenite (9 mg/kg) and supplemented with Zn (13 mg/kg). Two experimental groups were fed a diet supplemented with Zn (13 mg/kg) and Se at an adequate level (0.009 mg/kg); a half of the animals was supplemented with vitamin E. The results showed significant differences in the Se contents between the rat strains in case of Se-overdosed groups, where in the liver and kidney tissue Se contents of SHR rats exceeded 3- and 7-fold the normotensive ones. The Se uptake was altered by the vitamin E; no effect of Zn was observed. Activities of antioxidant enzymes were determined in the animal tissues indicating different patterns according to rat strain, tissue analysed, and administered Se dose. Thus, Se overdose, for instance, via an incorrectly prepared dietary supplement, can result in serious imbalances of the biochemical status of the animals.

The identification of risk and essential elements along the strobila of the rat tapeworm Hymenolepis diminuta.

The rat tapeworm Hymenolepis diminuta can bioconcentrate several elements to conspicuously higher concentrations than tissues of their definitive host. The main aim of this study was to locate parts of the tapeworm into which lead, cadmium, zinc, copper, manganese and iron are accumulated. Male Wistar rats were experimentally infected with H. diminuta and worms were exposed to two different forms of lead for 6 weeks through the oral exposure of their rat hosts. After the exposure period, the element levels were determined in the posterior and anterior proglottids of the tapeworm. In all cases, lead concentrations were higher in the anterior parts than the posterior parts. Concentrations of cadmium, copper, iron, manganese and zinc were also significantly higher in the anterior parts. Zinc concentrations showed an opposite trend, with higher zinc levels detected in the posterior part of the strobila, in the control group. The present study demonstrates that risk and essential elements are accumulated mainly into the anterior part of H. diminuta.

How the tapeworm Hymenolepis diminuta affects zinc and cadmium accumulation in a host fed a hyperaccumulating plant (Arabidopsis halleri).

The effects of plant-bound zinc (Zn) and cadmium (Cd) on element uptake and their interactions in a parasite-host system were investigated in a model experiment. Male Wistar rats were divided into four groups (C, P, TC and TP). Groups TC and TP were infected with the rat tapeworm Hymenolepis diminuta. Groups C and TC were fed a standard rodent mixture (ST-1) and received 10.5 mg of Zn per week, while groups P and TP were fed a mixture supplemented with the Zn- and Cd-hyperaccumulating plant Arabidopsis halleri at a dosage of 236 mg Zn/week and 3.0 mg Cd/week. Rats were euthanized after 6 weeks, and Cd and Zn levels were determined in rat and tapeworm tissue. The results indicate that tapeworm presence did have an effect on Cd and Zn concentrations in the host tissue; the majority of tissues in infected rats had statistically significant lower Zn and Cd concentrations than did uninfected rats. Tapeworms accumulated more zinc and cadmium than did the majority of host tissues. This important finding confirms the ability of tapeworms to accumulate certain elements (heavy metals) from the host body to their own body tissues. Thus, tapeworms can decrease heavy metal concentrations in host tissues.

Changes in soil microbial community functionality and structure in a metal-polluted site: The effect of digestate and fly ash applications.

Soil from Trhové Dusníky (Príbram, Czech Republic) is characterized by its high polymetallic accumulations in Pb-Ag-Zn due to mining and smelting activities. In previous studies performed in our research group, we have evaluated the potential use of amendments that would reduce the mobility and availability of metals such as Hg. We have observed that the application of digestate and fly ash in metal-polluted soil has an impact in immobilizing these metals. However, until now we have lacked information about the effect of these amendments on soil microbial functionality and communities. The multi-contaminated soil was used to grow wheat in a pot experiment to evaluate the impact of digestate and fly ash application in soil microbial communities. Soil samples were collected after 30 and 60 days of treatment. The digestate application improved chemical attributes such as the content in total organic carbon (TOC), water soluble carbon (WSOC), total soluble carbon (C), total soluble nitrogen (N), and inorganic N forms (NO3(-)) as consequence of high content in C and N which is contained in digestate. Likewise, microbial activity was greatly enhanced by digestate application, as was physiological diversity. Bacterial and fungal communities were increased, and the microbial biomass was highly enhanced. These effects were evident after 30 and 60 days of treatment. In contrast, fly ash did not have a remarkable effect when compared to digestate, but soil microbial biomass was positively affected as a consequence of macro- and micro-nutrient sources applied by the addition of fly ash. This study indicates that digestate can be used successfully in the remediation of metal-contaminated soil.

The influence of soil organic carbon on interactions between microbial parameters and metal concentrations at a long-term contaminated site.

The effects of lead, zinc, cadmium, arsenic and copper deposits on soil microbial parameters were investigated at a site exposed to contamination for over 200 years. Soil samples were collected in triplicates at 121 sites differing in contamination and soil organic carbon (SOC). Microbial biomass, respiration, dehydrogenase activity and metabolic quotient were determined and correlated with total and extractable metal concentrations in soil. The goal was to analyze complex interactions between toxic metals and microbial parameters by assessing the effect of soil organic carbon in the relationships. The effect of SOC was significant in all interactions and changed the correlations between microbial parameters and metal fractions from negative to positive. In some cases, the effect of SOC was combined with that of clay and soil pH. In the final analysis, dehydrogenase activity was negatively correlated to total metal concentrations and acetic acid extractable metals, respiration and metabolic quotient were to ammonium nitrate extractable metals. Dehydrogenase activity was the most sensitive microbial parameter correlating most frequently with contamination. Total and extractable zinc was most often correlated with microbial parameters. The large data set enabled robust explanation of discrepancies in organic matter functioning occurring frequently in analyzing of contaminated soil processes.

Sorption behavior of Cd, Cu, Pb, and Zn and their interactions in phytoremediated soil.

The aim of our study was to compare the sorption properties of a contaminated soil before and after two types of phytoremediation (natural phytoextraction vs. phytostabilization with dolomite limestone (DL) application). Soil from a pot experiment in controlled greenhouse conditions performed for two vegetation periods was used for the study. Lead, as the main contaminant in the studied soil, was easily desorbed by Cu, especially due to the increased affinity of Cu for soil organic matter; hence input of Cu to the studied soil can present another environmental risk in soils contaminated with other metals (such as Pb). In addition, the sorption behavior of chosen metals from single-element solutions differed from multielement solutions. The obtained results proved the different sorption behavior of metals in the single-element solution compared to the multi-element ones. Soil sorption behavior of Cd, Cu, and Zn decreased with the presence of the competitive metals; nevertheless, Pb sorption potential was not influenced by other competitive metals. Natural phytoextraction showed no significant effect on the sorption of Cd, Cu, Pb, and Zn onto the soil On the other hand, phytostabilization associated with DL application improved the soil sorption efficiency of all chosen metals, especially of Cu.

Effect of lead in water on the absorption of copper, iron, manganese and zinc by sheep (Ovis aries) infected with sheep tapeworm (Moniezia expansa).

The sheep tapeworm (Moniezia expansa) and its host Ovis aries were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) for their copper, iron, manganese, zinc and lead levels. Element concentrations in cestode parasites were compared to those in various organs (liver, kidney, and muscle) of sheep. Tapeworms in the small intestine of sheep that were administered 2g of Pb(CH(3)COO)(2) per os daily (7 days) had significantly higher lead concentrations than sheep tissues. Cu levels significantly increased after Pb administration in sheep muscle and sheep tapeworms. Contrarily, Zn content significantly decreased in sheep muscle, but significantly increased in sheep tapeworms. However, Mn content significantly decreased after Pb administration in sheep tapeworms. Furthermore, Fe content significantly decreased after Pb administration in sheep liver and kidneys.

Experimental studies on the cadmium accumulation in the cestode Moniezia expansa (Cestoda: Anoplocephalidae) and its final host (Ovis aries).

The tapeworm Moniezia expansa and naturally infected sheep were investigated with respect to their cadmium accumulation. Cadmium chloride (CdCl(2), 0.2 g) was added to 10 ml of distilled water and administered orally to the sheep every day for a period of 1 week. The cadmium content of M. expansa was lower than that in the liver tissues of sheep, although this difference was not significant. The highest mean cadmium concentrations were found in the liver of sheep infected with M. expansa (24.5+/-11.5 mgkg(-1) dry weight). The mean cadmium concentration measured in M. expansa was 21.5+/-19.2 mgkg(-1) dry weight, which was 31 and 1.5 times higher than levels determined in the muscle and kidney of the host, respectively, but 0.9 times lower than levels determined in the liver of host. Sheeps with M. expansa infection always had higher cadmium concentrations in the tissues (with the exception of the blood) than their uninfected conspecifics.

Experimental studies on the lead accumulation in the cestode Moniezia expansa (Cestoda: Anoplocephalidae) and its final host (Ovis aries).

The tapeworm Moniezia expansa and naturally infected sheep were investigated with respect to their lead accumulation. Lead-Pb(CH(3)COO)(2) was added to the distilled water and administered orally to the sheep every day for a period of 1 week. After the exposure period the sheep were killed and the metal levels were determined in the muscle, liver, kidney and blood of the sheep as well as in the cestode parasites (Moniezia expansa). The impact of an infection with the cestode Moniezia expansa and a simultaneous Pb exposure, on the concentrations of heavy metals in the host kidney, liver, muscle, blood and cestodes was studied. The concentration of lead in the cestodes was on average 458, 5 and 4-fold higher in the cestodes than in the muscle, liver and kidney of the host, respectively. Parasitised sheep accumulated significantly less lead in their tissues than their uninfected conspecifics (ANOVA test, P < or = 0.05). Also the differences between host's tissues and tapeworms were found to be significant (ANOVA test, P < or = 0.05). Thus, this study reveals that lead accumulation also occurs in cestodes parasitizing mammals. The host-parasite-system sheep-Moniezia expansa appears to be a useful and promising bioindication system especially in farming (rural, agricultural) and the natural ecosystem.

Mobility of arsenic and its compounds in soil and soil solution: the effect of soil pretreatment and extraction methods.

The effect of soil extraction procedures and/or sample pretreatment (drying, freezing of the soil sample) on the extractability of arsenic and its compounds was tested. In the first part, five extraction procedures were compared with following order of extractable arsenic portions: 2M HNO(3)>>0.43 M CH(3)COOH>or=0.05 M EDTA>or=Mehlich III (0.2M CH(3)COOH+0.25 M NH(4)NO(3)+0.013 M HNO(3)+0.015 M NH(4)F+0.001 M EDTA) extraction>>water). Additionally, two methods of soil solution sampling were compared, centrifugation of saturated soil and the use of suction cups. The results showed that different sample pretreatments including soil solution sampling could lead to different absolute values of mobile arsenic content in soils. However, the interpretation of the data can lead to similar conclusions as apparent from the comparison of the soil solution sampling methods (r=0.79). For determination of arsenic compounds mild extraction procedures (0.05 M (NH(4))(2)SO(4), 0.01 M CaCl(2), and water) and soil solution sampling using suction cups were compared. Regarding the real soil conditions the extraction of fresh samples and/or in situ collection of soil solution are preferred among the sample pretreatments and/or soil extraction procedures. However, chemical stabilization of the solutions should be allowed and included in the analytical procedures for determination of individual arsenic compounds.

Mobility assessment and validation of toxic elements in tunnel dust samples--subway and road using sequential chemical extraction and ICP-OES/GF AAS measurements.

The modified BCR three step sequential extraction procedure has been applied to homogenized urban dust samples collected in sedimentation chambers of two Prague tunnels (road, Letna, subway, and station Museum), and to SRM 1648 urban particulate matter (NIST) to validate the applicability of the procedure. Analyte concentrations in the fourth step were calculated from the total content of analytes determined and verified before, in case of the SRM 1648 certified values have been utilized. Concentrations of chosen elements As, Cd, Cr, Mn, Ni, Pb, Zn (Cu, Fe) in each fraction were measured by ICP-OES and GF AAS (arsenic determination) methods. The work has been focused on (i) levels investigation of toxic elements in dust samples and their distribution following a three-stage sequential extraction procedure, (ii) finding differences between two tunnel samples utilizing the estimation of mobility of trace elements, some macro-component comparisons and main mineralogical phases determinations by XRD analysis, (iii) validation of the proposed procedure using SRM 1648 Urban Particulate Matter (NIST) and comparative data obtained by a capillary electrophoresis (CE) method.

Combination of classical dry ashing with stripping voltammetry in trace element analysis of biological materials: review of literature published after 1978.

Critical statements have appeared recently in the literature concerning the need for classical dry ashing in trace element analysis of biological materials. In contrast, respected institutions (AOAC, Nordic Committee on Food Analysis, etc.) as well as numerous other laboratories have developed, verified, and/or successfully used classical dry ashing in practical analyses of a number of materials of biological origin. Hence, it is desirable to find out under which conditions the latter decomposition technique yields good and accurate results. Since electroanalytical techniques are among the most demanding with regard to the completeness of the biological matrix removal, we decided to critically review the literature published after 1978 in which classical dry ashing is combined with some version of electroanalytical measurement. It emerged from this review that in particular the charring step requires careful performing. When performed well, classical dry ashing leads to complete removal of the organic matrix and to accurate analytical results for a number of determined elements.

Interlaboratory analysis of IRM NSC-21 Compost Vitahum.

The preparation of internal reference material NSC-21 Compost Vitahum, including its stabilization, homogeneity testing, and evaluation of an interlaboratory comparison in which 19 laboratories took part using several analytical methods is described. From the results of the intercomparison, consensus values were derived for the contents of Cd, Cu, Ni, Pb, and Zn, whereas for As, Co, Cr, Fe, Hg and Mn, information values were derived. Bimodal distribution of the As and Cr results was obtained, presumably because of incomplete dissolution of the elements from the matrix if insufficiently aggressive decomposition procedures were employed. Some problems encountered were elucidated by application of neutron activation analysis (NAA) in its nondestructive and destructive (radiochemical) modes.

Cadmium, lead and mercury levels in feeding yeast produced in Czechoslovakia.

Ninety-six samples of the feeding yeast known as VITEX were analyzed for Cd, Pb and Hg content during 1987-1989. Cadmium content ranged from 0.30 to 5.12 mg/kg(-1), lead content from 0.21 to 3.01 mg/kg(-1) and mercury content from 0.008 to 0.187 mg/kg(-1). Our findings meet the current government standards (max. allowed Pb = 5.00, Cd = 0.50 and Hg = 0.100 mg/kg(-1)) only for lead, and with five exceptions, for mercury. With two exceptions, all cadmium levels found in the samples exceeded the limit. One raw material - the wood chips - was shown to be the main source of cadmium in the technological process. Relatively high Hg contents were measured in the wood chips (up to 0.155 mg/kg(-1)); the highest Hg level (1.105 mg/kg(-1)) however was found in a sample of KOH.

Natural levels of lead, cadmium and mercury in tissues and hair of newborn calves from different areas of Czechoslovakia.

Liver, kidney, muscle and hair samples from newborn, born-dead or found-dead calves were collected within 10 days after parturition, for the determination of Pb, Cd and Hg levels. Differential pulse anodic stripping voltammetry at the static mercury dropping electrode was used for Pb and Cd determination after dry ashing of the samples. Cold-vapour atomic absorption spectrometry was used for direct Hg determination. The aim of the study was to monitor background Pb, Cd and Hg levels in vital and important tissues of newborn calves in which nutritional influence was negligible. Three geographic areas in Czechoslovakia were monitored (A, B and C). The following ranges of mean values for all animals were obtained (mg kg-1, wet wt): Pb--muscle (0.04-0.25), liver (0.10-0.29), kidney (0.05-0.43), hair (0.11-0.55); Cd--muscle (0.007-0.038), liver (0.008-0.073), kidney (0.007-0.062), hair (0.009-0.074); Hg--muscle (0.002-0.071), liver (0.005-0.18), kidney (0.004-0.50), hair (0.07-0.77). The value obtained for heavy-metal levels (Pb, Cd, Hg) indicated that there is a significant difference between the groups of found-dead and slaughtered calves from the Nymburk region (muscle--Pb, Cd; liver--Pb; kidney--Pb, Cd). Unexplained high Hg levels in hair samples were measured in the Hradec Králové region.