Yasuhisa Yoshida

Urinary fluoride monitoring of industrial hydrofluoric acid exposure

Preworkshift and postworkshift urinary fluoride concentrations were measured in 142 hydrofluoric acid (HF) workers and 82 unexposed workers aged 18 to 59. Postshift urinary fluoride concentration in HF workers was significantly higher than that in preshift or control workers. A linear relationship was observed between the mean values in urinary fluoride concentration and the HF concentration in the air. The mean urinary fluoride concentration of 4 ppm and its lower fiducial limit (95%, P = 0.05) of 2 ppm (specific gravity 1.024) were estimated corresponding to the atmospheric HF concentration of 3 ppm, which is the maximal allowable concentration recommended by the Japanese Association of Industrial Health and also the threshold limit value suggested by the American Conference of Governmental Industrial Hygienists. The results suggest that exposure to HF can be monitored by determining the urinary fluoride concentration.

Urine, serum and hair monitoring of hydrofluoric acid workers

SummaryTo define the relationship between fluoride (F) concentration in the serum, urine and hair of workers and the concentration of hydrofluoric acid (HF) in the work environment, pre- and postshift serum and urine samples of 142 HF exposed workers and 237 unexposed workers were examined. Hair specimens were also collected for the determination of F. To determine whether external contamination influences hair analysis, the control hair samples were kept in the work environment for one week. The pre-exposure levels in serum and urinary F in HF workers were higher (P<0.01) than the control values. This suggests that F excretion from the body continues for at least 12 hours. The postshift serum and urinary F concentrations of these workers were significantly higher (P<0.01) than the preshift concentrations. The levels of F in the hair of HF workers were also higher than in the control subjects. The concentrations of F in postshift serum and urine, and hair were in good correlation to each other. There was a linear relationship between mean serum and urinary F concentrations and HF concentration in the workplace. A mean F concentration of 82.3 μg/l in serum and 4 mg/l in urine with a lower fiducial limit (95%, P=0.05) of 57.9 μg/l in serum and 2 mg in urine were estimated to correspond to an atmospheric HF concentration of 3 ppm, which is the maximum allowable concentration recommended by Japan Association of Industrial Health and also the threshold limit value suggested by American Conference of Governmental Industrial Hygienists. F concentration in the hair increased after the hair samples were retained, however, it decreased to the reference value after washing treatment. The results support the speculation that F is excreted into the hair after long-term exposure to HF. From the results obtained, it was suggested that exposure to HF can be monitored by determining the serum, urinary and hair F concentrations.

An experimental study on the treatment of hydrofluoric acid burns

A 20% solution of hydrofluoric acid (HF) was applied to the skin of rats and a biomedical observation of the tissues and sera was made. Flushing with running water was effective for HF burns. By applying 2.5% calcium gluconate jelly, concentrations of fluoride in the urine and the tissues surrounding the injured region were reduced. Thus, the results proved that irrigation with running water and jelly applications were evaluated as the most effective therapy among various methods tested for HF burns.

Elemental analysis of hair among hydrofluoric acid exposed workers

SummaryThe concentrations of fluorine (F), sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), phosphorus (P), calcium (Ca), iron (Fe), nickel (Ni), zinc (Zn) and iodine (I) in the hair of 142 hydrofluoric acid (HF) exposed workers and 273 control subjects were analyzed by wavelength dispersive X-ray fluorescence spectrometry. Postshift urine and serum specimens were also collected for the determination of fluoride. To determine whether external contamination influences hair analysis, the control hair samples were kept in the work environment for one week. With the exception of lower K and Fe values, the levels of F and other elements in the hair of HF workers were higher than in the control subjects. The concentrations of F in hair and in postshift urine were in good correlation (r = 0.65). In the hair of HF workers F and Ca, F and Mg, F and P, F and AI were well correlated with each other (r > 0.6). F concentration in the hair increased after the sample was retained, however, it decreased to the reference value after washing. The levels of Ca, Mg and other elements did not change during the experiment.

Serum boron concentration from inhabitants of an urban area in Japan: Reference value and interval for the health screening of boron exposure

Boron (B) levels were determined in the serum of 980 healthy inhabitants living in an urban area of Japan by means of inductively coupled plasma emission spectrometry (ICPES).The results showed a log-normal distribution of serum B for both sexes, although there are age-related differences. In male subjects, serum B increases rapidly up to 49 yr of age, reaching a plateau between ages 50 and 69 yr old, followed by a gradual increase up to 70 yr or older. Female subjects exhibit a gradual increase up to the age of 70 yr old. The reference value for male and female subjects was 79.8 μg/L and 67.9 μg/L, and the reference interval was 33.3–191.2 μg/L and 29.5–154.9 μg/L, respectively.The obtained reference value and interval of the nonexposed group may be useful for health screening for B exposure, either for people living in regions with high levels of B in the environment, or for workers who are exposed to this element.

Serum fluoride as an indicator of occupational hydrofluoric acid exposure.

SummaryTo define the relationship between ionic fluoride concentration in the serum of workers and the amount of hydrofluoric acid (HF) in the work environment, pre-and postshift serum and urine samples of 142 HF workers and 270 unexposed workers were examined. The maximum and minimum concentrations of HF in the air in each workshop varied from the mean by less than 30%. The pre-exposure levels of serum and urinary fluoride in HF workers were higher (P < 0.001) than the control values. This suggests that fluoride excretion from the body continues for at least 12 h. The postshift serum and urinary fluoride concentrations of these workers were significantly higher (P < 0.001) than the preshift concentrations. A good correlation (r = 0.64) was obtained between postshift serum fluoride and postshift urine fluoride. There was a linear relationship between mean serum fluoride concentration and HF concentration in the workshop. A mean fluoride concentration of 82.3 μg/l with a lower fiducial limit (95%, P = 0.05) of 57.9 μg/l was estimated to correspond to an atmospheric HF concentration of 3 ppm. This is the maximum allowable environmental concentration recommended by the Japanese Association of Industrial Health, and it is also the threshold limit value suggested by the American Conference of Governmental Industrial Hygienists. The results demonstrate that exposure to HF can be monitored by determining the serum fluoride concentration.

The effect of hemodialysis upon serum levels of fluoride.

Serum and dialysate ionic fluoride (F-) were determined in 29 patients under hemodialysis (HD) treatment. Serum creatinine (Cr), blood urea nitrogen (BUN) and phosphorus (P) were also examined before and after HD in 92 patients including the above 29 patients under the same treatment. Results reveal that serum F- levels of the patients before and after HD were statistically higher than those of the healthy subjects. The dialysis clearance of F- was 55.6 +/- 101.3 ml/min and the value was statistically significantly lower than those of Cr, BUN (95%, p < 0.001) and P (95%, p < 0.01). Based on these results, it is concluded that despite a net clearance of F- during a given HD procedure, serum F- failed to return to normal.

Toxicological aspects of cadmium and occupational health activities to prevent workplace exposure in Japan: A narrative review

Chemicals are an essential part of modern manufacture processes. Their use must be managed with great attention in occupational settings to avoid serious detrimental effects to the health of employees. For example, cadmium compounds are indispensable for the production of nickel-cadmium rechargeable batteries or as chemical stabilizer in plastics. It is an exceptionally toxic heavy metal and personnel exposed to cadmium in the workplace meet with potential health risks that can lead to the development of kidney, skeletal and respiratory disorders. In consequence, proactive and systematical development of occupational hygiene and health activities are necessary to reduce chemical exposure to cadmium in the workplace. This review describes the known facts of cadmium toxicity, the biological effects of cadmium exposure, possible regulation measures to prevent occupational cadmium exposure in three industrial health management systems and discusses future cooperation programs in these systems, proactive safety activities and occupational safety and health management strategies.

Fluoride Clearance in the Aging Kidney

Abstract Several characteristics of the aging process related to renal function and fluoride metabolism were investigated. A cross-sectional analysis of 1088 healthy subjects by 10-year age groups showed a progressive linear decline in creatinine clearance (CCr) and fluoride clearance (CF). There was a significant reduction in CCr and CF after age 80. The amount of fluoride filtered through the glomeruli per minute (FF), tubular reabsorp-tion of fluoride (TRF) and its rate (%TRF), seemed to remain stable until age 79. The 24-hour excretion of fluoride and CF were well correlated with each other (r=0.83) in 7 patients with chronic renal failure (CRF) and 11 healthy subjects after fluoride administration. The results suggest that renal fluoride clearance decreased not only with the evidence of kidney disease but also with advancing age. For the health care of workers exposed to fluoride and of populations living in fluoride polluted areas, age may be an important factor to be considered.

Kinetics of Fluoride Excretion in Human Saliva

Abstract The fluoride found in saliva may depend largely on serum fluoride content which is affected mainly by the diet and by the kidney function of the individual. The present investigation was concerned with fluoride contents of the whole and parotid saliva from residents of a non-fluoridated community and from patients with chronic renal failure (CRF), whose ability to excrete fluoride was markedly decreased. Whole and parotid saliva and serum samples were obtained from eight hydrofluoric acid (HF) plant workers, five patients with CRF, and 40 healthy controls. The samples were taken at 6:00 a.m. in the fasting state, and this was followed by the respective fluoride dose. Salivary and serum samples were collected at fixed intervals over a 48-hour period. In the healthy subjects, a high degree of correlation (r=+0.99) was obtained between serum and salivary fluoride levels. Changes in fluoride content of the whole and parotid saliva after fluoride intake were similar to those of the sera. The salivary fluoride content of patients with CRF was three to six times higher than that of healthy subjects at any time of the day. In HF plant workers, post-shift salivary fluoride content was five to 50 times higher than that in sera, possibly due to oral contamination from the work environment. These results suggest that fluoride contents of the whole and parotid saliva reflected the body burden of fluoride in non-fluoridated healthy subjects.