Current Situation and Causes Analysis of Cadmium Pollution in the Kakehashi River Basin.

Cadmium (Cd) pollution is a public environmental problem worthy of attention. Long-term exposure to Cd may have adverse effects on human health. Our previous study showed that urinary concentration of Cd (U-Cd) in the residents decreased when Cd-polluted paddy soil was removed. However, from 2008 to 2014, the concentration of U-Cd increased. At the same time, the concentration of urinary ß2-microglobulin (ß2-MG), which is considered to be an early sign of cadmium-induced renal dysfunction, increased continuously. To find the cause of elevated urinary cadmium (U-Cd) in residents of cadmium-contaminated areas, we measured the concentration of cadmium in the blood (B-Cd) of 29 elderly residents (15 female and 14 male) and edible rice (R-Cd), and correlations between R-Cd, B-Cd, and U-Cd were analyzed in the formerly cadmium-polluted areas (the Kakehashi River basin). In 2016, we collected blood, urine, and rice samples from each participant. The analysis showed a significant correlation between age and B-Cd, U-Cd, and ß2-MG. However, there was no significant correlation between R-Cd and U-Cd, B-Cd, or ß2-MG concentrations. Although we found a slightly higher level of Cd in rice and urine than reported in 2008, we cannot be sure that it indicates an increased Cd contamination in the Kakehashi River basin because larger studies are required for such a conclusion. The increased urinary Cd concentrations in this area may be because Cd in tissues and organs returns to blood and urine as participants age, which leads to an increasing trend.

A 30-year follow-up study in a former cadmium-polluted area of Japan: the relationship between cadmium exposure and ß2-microglobulin in the urine of Japanese people.

Cadmium (Cd) is an environmental pollutant. Long-term exposure to Cd may lead to adverse health effects in humans. Our epidemiological studies showed that urinary Cd (U-Cd) concentrations increased from 2008 through 2014, although they decreased from 1986 through 2008. The aim of this study was to elucidate the long-term effects of the changing trend of cadmium exposure levels (U-Cd) on residents' renal function within 30 years after Cd exposure ceased. In 2016, urine samples were collected from each subject by visiting 20 elderly Japanese people (9 females and 11 males) living in the Kakehashi River basin, a previously Cd-polluted area in Ishikawa, Japan. The geometric means of the ß2-microglobulin (ß2-MG) and urinary Cd (U-Cd) continued to increase from 2014 until 2016. Furthermore, Cd concentration and ß2-MG in urine were still higher than those in the non-polluted areas in Japan. Multivariate linear regression was performed to associate ß2-MG (dependent variable) and U-Cd with sex and age (independent variables). Significant correlations were found among age, U-Cd, and ß2-MG, and these were clearer in females than in males. In summary, we propose that three decades after Cd exposure ceased, age is associated with ß2-MG more strongly than Cd for bodily impact. Moreover, renal tubular dysfunction is irreversible and worsens after exposure to Cd, with females being more sensitive to exposure.

Decreased serum testosterone levels associated with 17ß-hydroxysteroid dehydrogenase activity in 7-year-old children from a dioxin-exposed area of Vietnam.

Since 2008, we have conducted epidemiological cohort studies on the relationship between dioxin exposure and disruption with children in the area sprayed with defoliants during the Vietnam War. In a long-term survey of children through the age of five, we observed androgen disruption due to decreased dehydroepiandrosterone (DHEA) and testosterone levels. In this study of 7-year-old, we separately elucidated androgen disruption for boys and girls, and discussed with respect to hormone disruption with sex differences on the steroid hormone biosynthesis process. This follow-up was conducted with 96 mother-child pairs in Vietnam (hotspot area: 45, non-sprayed area: 51). We took a questionnaire, the physical measurement and assayed 7 steroid hormones in their serum by LC-MS/MS. We examined the relationship between the hormone levels in the serum and dioxin levels in the maternal breast milk. The results showed that the serum DHEA level in the 7-year-old children in the hotspot recovered to levels in the non-sprayed area. The testosterone level of 66.5 pg/mL for boys in the non-sprayed area was 1.5 times the girls level of 44.6 pg/mL, a male-dominant effect. The testosterone level in boys and girls from the hotspot were significantly lower than in the non-sprayed area with no sex difference. The 17ß-hydroxysteroid dehydrogenase (17ß-HSD) activity was significantly higher in boys than in the girls from the non-sprayed area, but was significantly lower in the hotspot boys than in the non-sprayed area boys. Both the testosterone level and 17ß-HSD activity in the boys were inversely correlated with the TEQ total PCDD/Fs in the maternal breast milk. These results indicated that dioxin delayed the expression of the testosterone level and 17ß-HSD activity with growth in the 7-year-old boys. The serum DHEA in the 7-year-old children recovered to the levels of the children in the non-sprayed area.

Association of dioxin in maternal breast milk and salivary steroid hormone levels in preschool children: A five-year follow-up study of a Vietnam cohort.

Recent studies have found elevated dioxin levels inside some former US military air bases in Vietnam, known as hotspots. The aim of the present study was to evaluate the association of dioxin exposure and steroid hormone in preschool children in Vietnam. In 2010, 2011, 52 primiparae mother-infant pairs in the hotspot and 52 pairs in a non-exposure region were enrolled. For the final analysis, 26 vs 26 pairs were selected, who participated at all three surveys. Univariable and multivariable linear regressions were used to evaluate associations between hormone and dioxin congeners. Geometric mean total TEQ of PCDD/DFs in the hotspot were significantly higher than in the non-exposure region, 8.7 and 3.4 pg TEQ/g lipid, respectively. In the hotspot, salivary dehydroepiandrosterone (DHEA) was significantly higher in 1-year-old children (Boys = 123 pg/mL, Girls = 120 pg/mL) than in the non-exposure region (Boys = 28 pg/mL, Girls = 27 pg/mL). In contrast, DHEA was significantly lower in 5-year-old children (Boys = 70 pg/mL, Girls = 106 pg/mL) in the hotspot than in the non-exposure region (Boys = 496 pg/mL, Girls = 654 pg/mL). Salivary testosterone was significantly lower in the hotspot (Boys = 1.9 pg/mL, Girls = 1.9 pg/m; Boys = 1.0 pg/mL, Girls = 1.1 pg/mL, respectively) than in the non-exposure region (Boys = 3.7 pg/mL, Girls = 3.8 pg/m; Boys = 5.7 pg/mL, Girls = 7.0 pg/mL, respectively) at 3 years and 5 years of age. Higher levels of highly chlorinated dioxins in breast milk were associated with higher DHEA in 1-year-old and lower DHEA and testosterone levels in 5-year-old children. Our findings indicated that dioxins were associated with changes of DHEA and testosterone levels in preschool Vietnamese children.

Androgen disruption by dioxin exposure in 5-year-old Vietnamese children: Decrease in serum testosterone level.

Dioxins have been suspected to be potential substances causing endocrine disruptions in humans. We are conducting the research in one of three dioxin exposure areas (hotspots) in Vietnam. We previously reported that the salivary dehydroepiandrosterone (DHEA) level decreased in 3-year-old Vietnamese children and that it was significantly inversely correlated with polychlorinated dibenzodioxin/dibenzofuran levels in their mother's breast milk. In this study, we investigated the influence of exposure to dioxin on steroid hormone biosynthesis in the same children when they reached 5 years of age, focusing on androgens. Thirty-five and 50 mother-child pairs from dioxin hotspot and non-sprayed areas, respectively, participated in this study. Maternal breast milk was donated at 4 to 16 weeks postpartum in 2008 to measure dioxin levels by gas chromatography/high-resolution mass spectrometry. Serum was collected from 5-year-old children in 2013. Seven steroid hormones were measured by liquid chromatography/mass spectrometry. Most dioxin congeners in breast milk were 2- to 10-fold higher in the hotspot than in the non-sprayed area. DHEA and testosterone (T) were significantly lower in the hotspot and showed negative correlations with most dioxin congeners. Similar results were observed for the activities of cytochrome P450-17, 20 lyase (CYP17 lyase), and 17ß-hydroxysteroid dehydrogenase (HSD). Conversely, the elevated androstenedione (A-dione) level and 3ß-HSD activity in children from the hotspot were positively correlated with dioxin levels. Moreover, a positive correlation was shown between T and 17ß-HSD. It is possible that dioxin inhibits 17ß-HSD activity, leading to a decrease in the T level. Multiple regression analysis indicated that dioxin had a strong association with the DHEA, A-dione, and T levels. In conclusion, the present study suggests that dioxin is associated with low levels of DHEA and T and inhibition of the activity of steroidogenic enzymes such as CYP17 lyase and 17ß-HSD in 5-year-old children.

Effects of aging on cadmium concentrations and renal dysfunction in inhabitants in cadmium-polluted regions in Japan.

The absorption of cadmium (Cd) may lead to Cd-related diseases such as renal tubular dysfunction and bone disease, and it is known to take around 10-30 years to reduce Cd concentrations to half their original levels. Urinary ß2 -microglobulin (ß2 -MG), N-acetyl-ß-D-glucosaminidase (NAG), protein, glucose and albumin were used as indicators of renal dysfunction caused by Cd exposure. Our previous study found that urinary Cd concentrations had increased recently and that age was more strongly associated with urinary ß2 -MG concentration than recent Cd body burden. Therefore, the purpose of the present study was to investigate the effect of aging on Cd concentrations and renal dysfunction. The Cd, ß2 -MG, NAG, protein, glucose and albumin concentrations in the urine of 40 Japanese subjects (20 females and 20 males) environmentally exposed to Cd were collected. They lived in the Kakehashi River basin and were divided into three age categories: 50-69, 70-79 and 80-99 years. Significant differences in urinary Cd and ß2 -MG concentrations were found among age groups, with urinary Cd levels tending to increase with age in both sexes. No significant correlations were found between urinary Cd and any indicators of renal dysfunction. The correlation between age, Cd and indicators of renal dysfunction was observed more clearly in females than in males. Age is more strongly correlated with indicators of renal dysfunction than Cd body burden. Copyright © 2017 John Wiley & Sons, Ltd.