During the development of an embryo into a juvenile, the physiology and behavior of a fish change greatly, affecting exposure to and uptake of environmental pollutants. Based on experimental data with sole (Solea solea), an existing bioaccumulation model was adapted and validated to calculate the development of concentrations of persistent organic pollutants in the tissue of developing fish. Simulation revealed that toxic tissue concentrations of pollutants with log octanol-water partition ratio (K(OW)) > 5 peak at the moment when the larvae become free-feeding, when the lipid reserves are depleted. This may explain the delayed effects observed in fish early-life-stage experiments with exposed eggs. In the field, eggs can be exposed through maternal transfer to adult pollutant tissue concentrations, which will increase in the larva to peak tissue concentrations, exceeding those of the adult fish. The results demonstrate the risk of underestimating the effects of lipophilic persistent organic pollutants with log K(OW) > 5 in short-term, early-life-stage fish tests and underscore the importance of maternal transfer as an exposure route in the field situation.

The aim of this study was to describe the issue of changes in the concentration of some elements (Mn, Fe, Mg, Cu, K, Cr, Pb, Cd, and Ca) in the mineral composition of deciduous teeth and to answer the question whether there was a tendency to change the metal concentration, depending on children's age. Physiological replacement of deciduous teeth is preceded with the remodeling process occurring in the mineral structure. The elemental composition of deciduous teeth tissue during their natural loss is the result of these transformations. The subject of the study was deciduous teeth taken from the children (n = 45, aged 5–14 years), residing in southern Poland, obtained as a result of noninvasive physiological replacement. The concentration of metals in samples was determined over the atomic absorption spectroscopy method. The results of the research showed a statistically significant decrease in the concentration of the analyzed elements in deciduous teeth of older children compared to younger children. The total concentration of all metals studied against the Ca content, expressed as the value of the constant cationic equilibrium, did not change in a statistically significant manner, depending on the age of the children (p > 0.05).

BackgroundThe elemental composition of bones and teeth can allow exposure to heavy metals in the environment to be estimated. The aim of this study was to determine whether impacted mandibular teeth and the surrounding bones can be used as biomonitoring media to assess exposure to heavy metals.MethodsThe research materials were 67 impacted lower third molars and samples of the cortical bone removed when the wisdom teeth were surgically extracted. The samples were from people living in two areas with different environmental concentrations of heavy metals. The cadmium, chromium, copper, iron, lead, manganese, and zinc concentrations in the samples were determined by atomic absorption spectrometry with flame atomization.ResultsThe cadmium and lead concentrations in the impacted third molars and the bones surrounding the teeth were significantly higher for people living in the relatively polluted Ruda Slaska region than for people living in Bielsko-Biala region. Significantly higher chromium, copper, manganese, and zinc concentrations were found in the bones surrounding the impacted teeth from people living in Ruda Slaska than in the bones surrounding the impacted teeth from people living in Bielsko-Biala. The cadmium concentrations in impacted teeth and the surrounding bones were significantly positively correlated.ConclusionThe results indicated that impacted mandibular teeth and the surrounding mandibular bones may reflect the exposure of people to cadmium and lead in the environment. This conclusion, however, must be verified in future research projects designed to exclude the possibility of additional dietary, occupational, and other types of exposure to heavy metals.

No abstract

closed head injuries, canal paresis has been reported in a broad range of percentages (10 60%) uni l a t e r a l l y < ,7-7ü-7 1 and in 17% bilaterally/'5 A reduction to lower percentages (3.10%) of unilateral canal paresis has been noted in patients much later after the head i n j u r y .* * 7 I> Directional preponderance of rotatory responses was generally lacking in our previous study.•