Orofaciodigital syndrome type I in a girl with unilateral tibial pseudarthrosis.

The orofaciodigital syndromes are a group of possibly seven different malformation syndromes including oral, facial, and digital malformations. Type I has X linked dominant inheritance whereas the other types show autosomal recessive inheritance. An exact diagnosis is therefore important for genetic counselling. We here report a girl with orofaciodigital syndrome type I. She had cystic kidney disease at the age of 8 months which has not previously been reported in an infant with orofaciodigital syndrome. In addition she had unilateral tibial pseudarthrosis which has only rarely been reported in the orofaciodigital syndromes and in type II only.

Bioavailability of aluminium in the presence of humic substances at low and moderate pH.

Fish kills have been observed in lakes with low pH and high Al content. The monomeric inorganic Al seems to be the most acute toxic fraction. Humic lake waters, situated in acidified areas, often have high values of aluminium. However, the fraction of Al bound to humus is regarded as a relatively nontoxic form of Al. As pH is decreasing, the physical and chemical properties of humus change. The molecular size, electronegativity and colour decrease. An important question in this matter is the potential change in bioavailability of "Al-humus" as pH decreases. The bioavailability of the Al-humus complex was studied; in relation to surface water acidification and in relation to drinking water and human health. The work is based on the octanol/water partition coefficient (Khow), estimated by measuring the UV absorption at 254 nm. Al concentration is determined in the water phase and in the octanol phase. The results show that the amount of organic material soluble in the octanol phase relative to the amount in the aqueous phase increases with decreasing pH, while no Al is detected in the octanol phase. It is concluded that Al is only weakly bound to humus and consequently Al complexed with humus is of minor concern in bioaccumulation.

Effects of humus concentrations on benzo[a]pyrene accumulation from water to Daphnia magna: comparison of natural waters and standard preparations.

The bioaccumulation of benzo[a]pyrene (BaP) into Daphnia magna from two natural humic waters (one lake water and one bog water), and two humus preparations (Nordic Reference fulvic acid (Nordic FA) and a lyophilized concentrate) of the same aquatic origin was measured by using several dissolved organic carbon (DOC) concentrations for each sample. The partition coefficient (Kp) of BaP to the humus content of the water was determined by an equilibrium dialysis technique. In all four samples, an increase in humus concentration decreased the bioavailability of BaP in a logarithmic manner. The Nordic FA and the natural untreated humic water, from the same source as the water used for isolation of Nordic FA, gave a similar DOC bioaccumulation response and similar Kp values. The difference between the two natural humic waters was obvious, both in the accumulation experiments and the Kp values. The assumption that the total bound fraction of organic pollutant is not available for D. magna is not fully supported by this study.

Influence of aquatic humus and pH on the uptake and depuration of cadmium by the Atlantic salmon (Salmo salar L.).

Uptake and release of cadmium by Atlantic salmon at the concentrations near the background values for fresh water have been studied using cadmium labelled with Cd-109. Cumulation constant and biological half-time of release were established for different concentrations of humus and values of pH. The uptake is strongly dependent on the concentration of humus, showing a pronounced maximum at a DOC concentration of 2.7 mg/l. Release of cadmium is relatively slow, the biological half-time exceeds one year in the water without humic substances. Calculated bioconcentration factors range from 130 to several thousands, which may explain the wide differences of bioconcentration factor reported for natural systems. A general equation enabling calculation of bioconcentration factors for various conditions has been derived. An attempt is done to discuss the results from the point of view of physico-chemical forms of cadmium in respective waters. The amount of cadmium adsorbed on the surface of the fish was proved to be insignificant when compared with total concentration of cadmium bioaccumulated in the fish.