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The acute toxicity of hydrofluoric acid (HFA) was investigated in a 24-h lethal dose study of intravenous infusion in rats. The lethal dose lowest (LDLo) and LD50 were 13.1 and 17.4 mg/kg, respectively. Harmful systemic effects were also studied 1 h after acute sublethal exposure to HFA. The maximum dose was set at 9.6 mg/kg (LD5). Rats were injected with HFA (1.6, 3.2, 6.4 or 9.6 mg/kg), saline, sodium fluoride (NaF) or HCl solution. NaF and HCl solution concentrations corresponded to the F- and H+ concentrations of 9.6 mg/kg HFA. Blood urea nitrogen (BUN) and Cr were significantly increased in response to HFA concentrations greater than 3.2mg/kg. Acute glomerular dysfunction also occurred at HFA concentrations greater than 3.2 mg/kg. HCO3- and base excess (BE) were significantly decreased in the 6.4 and 9.6 mg/kg groups. Ca2+ was significantly decreased, and K+ was increased in the 9.6 mg/kg group. BUN was significantly increased in the NaF and HFA groups and was increased in the HFA group compared with that in the NaF group. Cr was significantly increased in the HFA group only. HCO3- and BE were significantly decreased in the NaF and HFA groups and were increased in the HFA group compared with values in the NaF group. Ca2+ was significantly decreased in the NaF and HFA groups, and K+ was significantly increased in the NaF and HFA groups. F- exposure directly affected serum electrolytes. Mortality was thought to be due to cardiac arrhythmia resulting from hypocalcemia and hyperkalemia. Metabolic acidosis and renal failure were more severe in response to HFA exposure than in response to NaF exposure because of more free F-, which has strong cytotoxicity, in the HFA group than in the NaF group. Lethal effects of HFA are promoted by exposure routes such as inhalation that cause rapid absorption into the body. Even low exposure to HFA can cause acute renal dysfunction, electrolyte abnormalities and metabolic acidosis. These complications result in a poor prognosis.

Objective: The aim of this study was to establish reference concentrations of urinary strontium by inductively coupled plasma atomic emission spectrometry (ICP-AES). Methods: For the determination of strontium, urine samples were collected from healthy Japanese (n=146; 115 males, 31 females; mean age, 33±9 years; age range, 18 to 58 years). The urine samples stored at or below −20°C were thawed with incubation at 40°C for 30 min and sediments were dissolved by vigorous shakings. Then, the samples were centrifuged at 3000 g for 5 min, and the supernatant was directly aspired into a P-5200-3600/1200 ICP-AES system from Hitachi Ltd., Tokyo, Japan. Results: A steeper increase in the S/N ratio and a good effective linearity of the calibration line was obtained at 407.771 nm in the range of 0-300 μg/L strontium standard solution. Urine samples having the same background signal as that of 18 MΩ cm ultrapure blank water, a good correspondence of the single peak pattern of the spectra, accuracy and precision of spike recovery were also confirmed. Urinary strontium concentrations showed a log-normal distribution and a geometric mean concentration of 143.9 μg/L, with 5-95% confidential interval of 40.9-505.8 μg/L. Conclusion: The results of this study will be useful as guidelines for the biological monitoring of strontium in normal subjects and in individuals therapeutically or environmentally exposed to strontium.

Evaluation of yttrium exposure in biological samples has not been fully examined. To evaluate yttrium nephrotoxicity, yttrium chloride was orally administered to male Wistar rats and the urine volume (UV) and N-acetyl-beta-D-glucosaminidase (NAG) and creatinine excretion (Crt) were measured in 24-h urine samples. The urinary yttrium concentration and excretion rate were determined by inductively coupled plasma-argon emission spectrometry (ICP-AES). Large significant decreases of UV (>30%) and Crt (>10%) were observed at yttrium doses of 58.3-116.7 mg per rat, but no significant NAG changes was observed. This response pattern shows that a high yttrium dosage alters glomerular function rather than the proximal convoluted tubules. A urinary yttrium excretion rate of 0.216% and good dose-dependent urinary excretion (r=0.77) were confirmed. These results suggest that urinary yttrium is a suitable indicator of occupational and environmental exposure to this element, an increasingly important health issue because recent technological advances present significant potential risks of exposure to rare earth elements. We propose that the ICP-AES analytical method and animal experimental model described in this study will be a valuable tool for future research on the toxicology of rare earth elements.

A Cr- or Ag-doped TiO2film was prepared by sol-gel and dip-coating process and used as the photocatalyst for CO2reforming under the visible light. The ratio of amount of Cr or Ag added to amount of Ti in TiO2sol solution (R) varied from 0 to 100 wt% or 0 to 50 wt%, respectively. The total layer number of Cr- or Ag-doped TiO2film (N) coated was changed. The CO2reforming performance with the Cr- or Ag-doped TiO2film was tested under a Xe lamp with or without ultraviolet (UV) light. As a result, whenNequals to 1, the concentration of CO which was a product from CO2reforming was maximized in Cr doping case forR= 70 wt% and in Ag doping case forR= 1 wt%, respectively. The best result of concentration of CO = 8306 ppmV, concentration of CH4= 1367 ppmV, concentration of C2H6= 1712 ppmV is obtained when with Cr doping in this study.

A Cr-doped film was prepared by sol-gel and dip-coating method and used as the photocatalyst for reforming under the visible light. The ratio of amount of Cr added to amount of Ti in sol solution (R) varied from 0 to 100 wt%. The total layer number of Cr-doped film (N) coated was up to 7. The reforming performance with the Cr-doped film was evaluated by illuminating under a Xe lamp with or without ultraviolet (UV) light. The concentration of CO which was a product from reforming was maximized for  wt% whenNequals to 1. The visible light responsibility was also maximized for  wt%. The amount of Cr within film coated on copper disc was increased with the increase inRup to 70 wt% and started to decrease whenRis over 70 wt%. The reforming performance of film with one layer Cr-doped was found better than that of film with multi Cr-doped layers under illuminating of UV light. Under the visible light, the performance was maximized at  wt% and with one layer Cr-doped.

The results of this study will be useful as guidelines for the biological monitoring of strontium in normal subjects and in individuals therapeutically or environmentally exposed to strontium.