Soil-invertebrate feeding birds can be exposed to high doses of toxic metals trough their diet. Recently, we have shown that nestling rooks Corvus frugilegus from several rookeries in Poland have a cadmium (Cd) tissue level diagnostic for acute contamination as well as an elevated level of lead (Pb). To explain the potential pathway of bioaccumulation of 11 essential and non-essential elements, including two metals of primary concern (Cd and Pb), in target issues of these nestlings, we analyzed the relationships between the dietary characteristics of stomach content (mass of digesta, number of cereal grains, plant and animal items, and grit particles) and concentrations of metals in the liver, kidneys, lung, muscles and bones. Our analysis showed in total 17 (8 negative and 9 positive) statistically signigicant relationships between the five analyzed dietary characteristics of stomach content nad concentrations of metals in the liver, kidneys, muscles and bones. We found a significant positive relationship between the number of animal food items and Cd-level in kidneys; and a negative relationship bewteen the number of plant items and Pb-level in the liver, and between the number of grit particles and Pb-level in kidneys. Despite the limitations of our study due to the different degree of digestion of some food items, our findings suggest high bioavailability of Cd from animal food items and a low level or reduce gastrointestinal absorption of Pb from plant food (mainly cereals). We urge further research on absorption of Cd and Pb from different dietary components and application of diet analysis to explain the complex nature of bioaccumulation of anthropogenic contaminants in the internal organs and tissues of birds and other species of animals, especially in species with a mixed plant-animal diet.
Ultrastructural and physiological effects of exposure to 1 ppm and 5 ppm of cadmium (Cd) on cultured cells of Koliella antarctica, a green microalga from Antarctica, were investigated. The amount of Cd in the alga rose with the increase of the metal concentration in the growth medium and most Cd remained outside the cells, bound to the components of the cell walls. The increase of Cd in the microalga was concomitant with the decrease of other elements, mainly calcium (Ca). Exposure to 1 ppm Cd slowed culture growth by inhibiting cell division and also caused the development of some misshapen cells with chloroplast showing disordered thylakoids. However, this concentration did not substantially affect the chlorophyll (Chl) content or photosystem (PS) activity. At 5 ppm, Cd cell growth suddenly stopped and some cells lysed. After a week of Cd contamination, the cells were enlarged and severely damaged. The chloroplasts showed great ultrastructural alterations and a reduced Chl content. Cd exposure negatively affected PSII, whose activity was almost completely lost after four days. and N. La Rocca ... [et al.].
The paper presents the results of research of surface water and sediment contamination by the specific pollutants in the Klabava River Basin, subcatchment of Vltava River in Central Bohemia, Czech Republic. The analysis of spatial and temporal dynamics of the contamination is based on the water and sediment chemistry data from the long-term monitoring maintained by the Vltava River Authority completed by the own monitoring established in the Klabava River basin. The research revealed that the most important water and sediment contamination loads are mainly concentrated in the industrial area between cities Hrádek and Rokycany situated on downstream of the river basin. The performed analysis identified the cadmium as the most critical parameter as its concentrations in surface water exceeded the references limits up to several hundred times. However, pollution with the specific organic substances was still below the critical limit, except for the AOX indicator. The results of sample-taking in the river basin allowed analyzing the effect of extreme flood in August 2002 on the changes in the sediment load by heavy metals. Contaminated sediments were mostly washed out by the inundation and this resulted in significantly lower values than were observed in the previous seasons. Repeated observations however indicate that the pollution concentrations are gradually reaching their original values. and Článek představuje výsledky výzkumu znečištění povrchových vod a sedimentů specifickým znečištěním v povodí Klabavy. Analýza vychází z dostupných dat o chemismu vody a plavenin ze sledování podniku Povodí Vltavy a z vlastních dat získaných rozbory vzorků odebraných na síti účelově zřízených profilů. Pro hodnocení chemismu sedimentů byly použity standardní metody - porovnání s pozaďovými hodnotami geogenního prostředí podle Turekiana a Wedepohla a zatřídění do tříd jakosti podle Igeo. Z výsledků vyplývá, že zatížení vody i sedimentů je soustředěno zejména do oblasti průmyslového a sídelního uskupení mezi Hrádkem a Rokycany. Varovné jsou zde především koncentrace kadmia ve vodě, které v této oblasti překračují referenční hodnoty i několiksetkrát, silnou zátěž potvrzují i analýzy sedimentu. Znečištění specifickými organickými látkami s výjimkou ukazatele AOX nedosahuje kritických hodnot. Výsledky vlastních odběrů umožnily rovněž zhodnotit vliv povodně v srpnu 2002 na změnu zátěže sedimentů. Kontaminované sedimenty byly povodní vyplaveny a hodnoty, naměřené bezprostředně po povodni, jsou výrazně nižší než v předchozím období. Díky pokračující zátěži se však postupně vrací k původním hodnotám.
The goldfish (Carassius auratus gibelio Bloch.) were exposed to cadmium in the concentration of 20 mg Cd/1 water under aquarium conditions for 1, 4, 7 and 15 days. After exposure to cadmium, the activities of superoxide dismutase (SOD) and catalase (CAT) were significantly decreased. At the same time, the liver ascorbic acid (AsA) content was increased.
Total superoxide dismutase (total SOD), copper zinc containing superoxide dismutase (CuZn SOD), and manganese superoxide dismutase (Mn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione- S-transferase (GST) activities as well as ascorbic acid (AsA), and vitamin E (vit E) concentrations were analysed in the liver of rats exposed to cadmium (15 mg Cd/day/kg), selenium (7 fig Se/day/kg), and to cadmium + selenium (15 mg Cd + 7 ptg Se/day/kg), and in control animals. Cadmium caused a decrease of total SOD, Mn SOD, CAT and GSH-Px but an increase of GST activity in the liver of rats. Contrary to cadmium, selenium caused a significant increase of the activity of these enzymes except for GSH-Px. By concomitant exposure to both cadmium and selenium, the toxic effects of cadmium on the activity of mentioned enzymes we abolished. In all exposed groups, the activity of enzyme glutathione-S-transferase was enhanced, indicating its increased role in prevention of lipid peroxidation. Cadmium decreased the concentration of AsA and increased the concentration of vitamin E in the liver, while selenium increased the concentration of both vitamins. However, by concomitant administration of cadmium and selenium, these changes were diminished and tended to reach control values.
Cadmium is often detected in areas contaminated by heavy metals and the incidence of this element in dangerous concentrations has been increasing due to anthropogenic activities. The aim of this research was to determine Cd concentrations in tissues, quantify compounds, pigments and enzymes, and to evaluate the gas exchange. Our aim was also to identify components that can modify and contribute to tolerance of Cassia alata against Cd toxicity. We used five Cd concentrations (0, 22, 44, 88, and 132 μM) to validate our hypothesis. The Cd concentrations in tissues of C. alata plants increased significantly, compared with the control treatment, in the following graduated sequence: root > leaf > stem. Progressive enhancement in glutathione (GSH) was verified in plants treated with all Cd concentrations used, when compared with treatment without Cd. Antioxidant enzyme activities presented similar patterns with progressive enhancements, being a desirable characteristic for plants with a potential to hyperaccumulate Cd. Our results suggest that C. alata plants can be used for phytoremediation programs. Their defense mechanism is based on Cd accumulation in roots, coupled with increase in GSH and the efficient activity of antioxidant enzymes that contribute to minimize the oxidative stress and consequently improve the protection of the metabolic machinery., J. R. R. Silva, A. R. Fernandes, M. L. Silva Junior, C. R. C. Santos, A. K. S. Lobato., and Obsahuje bibliografii
The toxicity of cadmium and zinc at concentrations ranging from 0.1 to 100 µg/l was investigated against the activity of Diplostomum spathaceum (Rudolphi, 1819) cercariae. Over a 24 h exposure period a significant reduction in cercarial activity occurred in solutions of cadmium, zinc, and a mixture of cadmium and zinc at all concentrations. Reduced cercarial activity also occurred in all toxicant solutions compared with controls after only 6 h exposure indicating that cercariae were vulnerable during the period of maximum cercarial infectivity (0-5 h). The mechanisms of metal toxicity and their importance to parasite transmission are discussed.
The protective role of nutrition factors such as calcium, vitamin D and vitamin K for the integrity of the skeleton is well understood. In addition, integrity of the skeleton is positively influenced by certain trace elements (e.g. zinc, copper, manganese, magnesium, iron, selenium, boron and fluoride) and negatively by others (lead, cadmium, cobalt). Deficiency or excess of these elements influence bone mass and bone quality in adulthood as well as in childhood and adolescence. However, some protective elements may become toxic under certain condition s, depending on dosage (serum concentration), duration of treatment and interactions among individual elements. We review the beneficial and toxic effects of key elements on bone homeostasis., I. Zofkova, M. Davis, J. Blahos., and Obsahuje bibliografii
Cadmium in the dose of 1 mg/animal/day was administered to guinea-pigs in the form of CdCl2 dissolved in drinking water during short-term (5 weeks) and subchronic (12 weeks) experiments. Both the control and cadmium-treated groups were divided into two subgroups, according to low (2 mg/animal/day) and high (100 mg/animal/day) vitamin C intake. Subchronic cadmium treatment caused copper deficiency indicated by a dramatic decrease of copper concentration in the liver and serum and by its moderate decrease in the testes and brain. Cadmium significantly increased zinc concentrations in the kidneys during the whole experiment and decreased the level of zinc in the serum after subchronic cadmium treatment. In the control groups, the levels of zinc and copper in the serum were lowered after 5 weeks of high vitamin C doses. High doses of vitamin C in cadmium-treated guinea-pigs decreased the levels of copper in the testes, brain and serum. These observations suggest that cadmium intake in relatively high doses might potentiate the development of copper deficiency, and high doses of vitamin C aggravate, to a certain extent, copper depletion in some important organs and serum of guinea-pigs.