Cadmium-induced oxidative stress and histological damage in the myocardium. Effects of a soy-based diet.

Cd exposure has been associated to an augmented risk for cardiovascular disease. We investigated the effects of 15 and 100 ppm of Cd on redox status as well as histological changes in the rat heart and the putative protective effect of a soy-based diet. Male Wistar rats were separated into 6 groups and treated during 60 days as follows: groups (1), (2) and (3) were fed a casein-based diet; groups (4), (5) and (6), a soy-based diet; (1) and (4) were given tap water; (2) and (5) tap water containing 15 ppm of Cd²âº; and (3) and (6) tap water containing 100 ppm of Cd²âº. Serum lipid peroxides increased and PON-1 activity decreased in group (3). Lipoperoxidation also increased in the heart of all intoxicated groups; however protein oxidation only augmented in (3) and reduced glutathione levels diminished in (2) and (3). Catalase activity increased in groups (3) and (6) while superoxide dismutase activity increased only in (6). Glutathione peroxidase activity decreased in groups (3) and (6). Nrf2 expression was higher in groups (3) and (6), and MTI expression augmented in (3). Histological examination of the heart tissue showed the development of hypertrophic and fusion of cardiomyocytes along with foci of myocardial fiber necrosis. The transmission electron microscopy analysis showed profound ultra-structural damages. No protection against tissue degeneration was observed in animals fed the soy-based diet. Our findings indicate that even though the intake of a soy-based diet is capable of ameliorating Cd induced oxidative stress, it failed in preventing cardiac damage.

Modelling spatial and temporal variations in the water quality of an artificial water reservoir in the semiarid midwest of Argentina.

Temporal and spatial patterns of water quality of an important artificial water reservoir located in the semiarid Midwest of Argentina were investigated using chemometric techniques. Surface water samples were collected at 38 points of the water reservoir during eleven sampling campaigns between October 1998 and June 2000, covering the warm wet season and the cold dry season, and analyzed for dissolved oxygen (DO), conductivity, pH, ammonium, nitrate, nitrite, total dissolved solids (TDS), alkalinity, hardness, bicarbonate, chloride, sulfate, calcium, magnesium, fluoride, sodium, potassium, iron, aluminum, silica, phosphate, sulfide, arsenic, chromium, lead, cadmium, chemical oxygen demand (COD), biochemical oxygen demand (BOD), viable aerobic bacteria (VAB) and total coliform bacteria (TC). Concentrations of lead, ammonium, nitrite and coliforms were higher than the maximum allowable limits for drinking water in a large proportion of the water samples. To obtain a general representation of the spatial and temporal trends of the water quality parameters at the reservoir, the three-dimensional dataset (sampling sites×parameters×sampling campaigns) has been analyzed by matrix augmentation principal component analysis (MA-PCA) and N-way principal component analysis (N-PCA) using Tucker3 and PARAFAC (Parallel Factor Analysis) models. MA-PCA produced a component accounting for the general behavior of parameters associated with organic pollution. The Tucker3 models were not appropriate for modelling the water quality dataset. The two-factor PARAFAC model provided the best picture to understand the spatial and temporal variation of the water quality parameters of the reservoir. The first PARAFAC factor contains useful information regarding the relation of organic pollution with seasonality, whereas the second factor also encloses information concerning lead pollution. The most polluted areas in the reservoir and the polluting sources were identified by plotting PARAFAC loadings as a function of the UTM (Universal Transverse Mercator) coordinates.

Lead and cadmium accumulation in anuran amphibians of a permanent water body in arid Midwestern Argentina.

PURPOSE: Heavy metals have been detected in water and sediments from the Embalse La Florida, an artificial lake in the arid region of San Luis province, Argentina, representing one of the few sources of permanent water for reproduction of native anuran species. This study assesses lead (Pb) and cadmium (Cd) concentrations in the anuran species found in this water reservoir as well as differences between compounds, species and sites of collection. METHODS: Adult anuran amphibians were collected on the north and south shores of the Embalse La Florida and Pb and Cd concentrations were measured in whole body homogenates digested using wet ashing techniques. RESULTS: All individuals of the six species assayed had detectable levels of Pb and Cd that ranged from 1.19 to 5.57 µg/g dry mass and from 1.09 to 6.86 µg/g dry mass, respectively. Anuran amphibians collected in the more contaminated south shore accumulated 21% more Cd and 40% more Pb than individuals from the less altered north shore. Cd and Pb accumulation was not significantly correlated with the concentration in water at the site of collection. CONCLUSIONS: Amphibians of the Embalse La Florida accumulate Cd and Pb. Between and within species, differences were detected in Cd and Pb concentrations. Differences in metal concentrations between species, metals, and individuals collected on shores of the Embalse La Florida with different contamination, were detected. Therefore, it is crucial to implement adequate policies to protect amphibians from the accelerated urban development experienced in this location.

Organochlorine contamination in anuran amphibians of an artificial lake in the semiarid midwest of Argentina.

Artificial water reservoirs are important for fauna in arid-semiarid regions, because they provide suitable habitats for species that depend on water, such as amphibians. Organochlorine pesticides (OCPs) are toxic, persistent compounds that tend to bioaccumulate and bioconcentrate. We evaluated contaminant levels in anurans from an artificial lake (Embalse La Florida) in a semiarid region of the Midwest Argentina. This lake is one of the few sources of permanent water in the area. OCPs were detected in all individuals. Levels ranged from 2.34 +/- 0.62 ng/g wet mass of heptachlors to 9.76 +/- 1.76 ng/g wet mass of hexachlorocyclohexanes. The distribution pattern of OCP was Sigma HCH > Sigma DDT > endosulfan > Sigma chlordane > metoxichlor > Sigma aldrin > Sigmaheptachlor. Contaminant levels in individuals were positively correlated with contaminant levels in the water. Burden differed between species, but not among sites differing in water contaminant levels. Results suggest that anurans may concentrate OCPs and thus provide an important source of exposure for amphibian predators. This study provides important information for potential risk assessment of amphibians in the region and contributes to our understanding of the extent of OCP contamination.

Organochlorine pesticide contamination in three bird species of the Embalse La Florida water reservoir in the semiarid midwest of Argentina.

Organochlorine pesticides (OCs) have a variety of acute and chronic pathological effects on animals, are persistent in the environment and are accumulated in adipose tissue of animals. In Argentina there are few studies reporting the OC contamination in the fauna. Moreover, no data are available for an ecologically relevant region, the arid-semiarid midwest region of Argentina. Recently, it was reported OC contamination in the water of an important artificial water reservoir of this area, the Embalse La Florida in the San Luis province. The present study aims to provide OC baseline data for birds of Embalse La Florida and to evaluate the potential risk of OC contamination for the local avifauna. We selected two fish-eating species, Podiceps major (great grebe) and Phalacrocorax brasilianus (neotropic cormorant) and one omnivore species, Pitangus sulphuratus (great kiskadee) to evaluate OC contamination. Alpha-, beta-, delta- and gamma-hexachlorocyclohexane (SigmaHCH), p,p'-DDT, p,p'-DDD, p,p'-DDE and methoxychlor (SigmaDDT), aldrin, dieldrin, endrin and endosulfan (SigmaALD) and, cis-chlordane, trans-chlordane, heptachlor, heptachlor epoxide(SigmaCHL) were measured in adipose tissue of two male great grebes, six neotropic cormorant (3 of each sex) and four great kiskadees (2 of each sex). We detected all OC pesticides assayed [SigmaHCH range: ND to 3168.41 ng/g fat, SigmaCHL range: ND to 4961.66 ng/g fat, SigmaALD range: 287.07 to 9161.70 ng/g fat, SigmaDDT range: 1068.98 to 6479.84 ng/g fat], with the exception of p,p'-DDT. Summed OC concentration in all bird species ranged from 2684.91 to 19231.91 ng/g fat. The omnivore had significantly greater concentrations of SigmaCHLs than fish-eating species. Females of the neotropic cormorant had significantly higher amounts of SigmaHCH and SigmaCHL than males. The OC concentrations detected in birds were lower than those reported in the literature that are associated with deleterious effects on survival or reproduction in others species of birds. This study is the first report of OC contamination in birds of the midwest region of Argentina and constitutes a starting point for future studies that evaluate temporal changes of OCs in birds in this region.