Background: Cadmium and lead are widespread and non-biodegradable pollutants of great concern to human health. In real life scenarios, we are exposed to mixtures of chemicals rather than single chemicals, and it is therefore of paramount importance to assess their toxicity. In this study, we investigated the toxicity of Cd and Pb alone and as a mixture in an animal model of acute exposure. Methods: Experimental groups received a single treatment of aqueous solution of Cd-chloride (15 and 30 mg/kg body weight (b.w.) and Pb-acetate (150 mg/kg b.w.), while the mixture group received 15 mg Cd/kg b.w. and 150 mg Pb/kg b.w. Toxic effects of individual metals and their mixture were investigated on hematological and biochemical parameters, and the redox status in the plasma, liver, and kidneys of treated Wistar rats. Results: Tissue-specific changes were recorded in various parameters of oxidative damage, while the accumulation of metals in tissues accompanied the disturbances of both hematological and biochemical parameters. It was observed that the level of toxic metals in tissues had a different distribution pattern after mixture and single exposure. Conclusions: Comprehensive observations suggest that exposure to Cd and Pb mixtures produces more pronounced effects compared to the response observed after exposure to single metal solutions. However, further research is needed to confirm toxicokinetic or toxicodynamic interactions between these two toxic metals in the organisms.

Phthalates and bisphenol A, classified as endocrine disruptors, have weak estrogenic, anti-androgenic properties, and affect thyroid hormone regulation. The aim of this study on male rats was to compare the subacute toxic effects of low doses of single compounds (bis (2 –ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and bisphenol A (BPA)) with the effects of their mixture through different biochemical, hormonal, and hematological parameters. Rats were divided into five experimental groups: Control (corn oil), DEHP (50 mg/kg b.w./day), DBP (50 mg/kg b.w./day), BPA (25 mg/kg b.w./day), and MIX (50 mg/kg b.w./day DEHP + 50 mg/kg b.w/day DBP + 25 mg/kg b.w./day BPA). Animals were sacrificed after 28 days of oral treatment and blood was collected for further analysis. The results demonstrated that the mixture produced significant changes in lipid profile, liver-related biochemical parameters, and glucose level. Furthermore, the opposite effects of single substances on the thyroxine level have been shown in comparison with the mixture, as well as a more pronounced effect of the mixture on testosterone level. This study contributes to the body of knowledge on the toxicology of mixtures and gives one more evidence of the paramount importance of mixture toxicity studies, especially in assessing the endocrine disruptive effects of chemicals.

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This study explores relation between dental fluorosis occurrence in schoolchildren, residents of Ritopek, a small local community near Belgrade, and fluoride exposure via drinking water. Additionally, fluoride levels were determined in children's urine and hair samples, and efforts were made to correlate them with dental fluorosis. Dental fluorosis and caries prevalence were examined in a total of 52 schoolchildren aged 7-15 years (29 boys and 23 girls). Fluoride levels in three types of samples were analyzed using composite fluoride ion-selective electrode. Results showed high prevalence of dental fluorosis (34.6 %) and low prevalence of dental caries (23.1 %, mean DMFT 0.96) among children exposed to wide range of water fluoride levels (0.11-4.14 mg/L, n = 27). About 11 % of water samples exceeded 1.5 mg/L, a drinking-water quality guideline value for fluoride given by the World Health Organization (2006). Fluoride levels in urine and hair samples ranged between 0.07-2.59 (n = 48) and 1.07-19.83 mg/L (n = 33), respectively. Severity of dental fluorosis was positively and linearly correlated with fluoride levels in drinking water (r = 0.79). Fluoride levels in urine and hair were strongly and positively correlated with levels in drinking water (r = 0.92 and 0.94, respectively). Fluoride levels in hair samples appeared to be a potentially promising biomarker of fluoride intake via drinking water on one hand, and severity of dental fluorosis on the other hand. Based on community fluorosis index value of 0.58, dental fluorosis revealed in Ritopek can be considered as "borderline" public health issue.