Dioxin hot spots in Vietnam

Toxicological & Environmental Chemistry

Hưng

et al. 2011

Human exposure to polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF), especially 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD), was investigated in Vietnam since initial severe adverse health effects were reported in the late 1970s. The purpose of this study was to determine the effects of dioxin exposure on steroid hormones of primiparae in an Agent Orange/dioxin hot-spot and a non-exposed area in Vietnam. Sixteen primiparae (8 at each site), all of whom were aged between 20 and 30 years with infants aged between 4 and 16 weeks, agreed to participate in this study. The mean dioxin levels in breast milk of primiparae from the hot-spot area, in terms of PCDD, PCDF, and PCDD þ PCDF toxic equivalents (TEQ), were significantly higher than those for the non-exposed area. PCDD TEQ, PCDF TEQ, and PCDD þ PCDF TEQ levels showed a significant correlation with dehydroepiandrosterone (DHEA), androstenedione (A-dione), and estradiol (E2) in the saliva of primiparae in a combination of hot-spot and non-exposed areas in Vietnam. The dose-response curve between salivary E2 or A-dione levels and dioxin levels was U-shaped in humans. This study provides an overview of studies regarding dioxin hot-spots and effects on human health and steroid hormone levels in particular, with a focus on the toxicity attributed to dioxins and furans. Furthermore, causal evidence regarding the effects of dioxins on endocrine disruption in humans is provided.

Section: Discussionmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Dioxin levels in the breast milk and estradiol and androgen levels in the saliva of Vietnamese primiparae

Nhu

Toxicological & Environmental Chemistry

Hưng

et al. 2011

“…Another study has been undertaken recently to detect dioxin hot spots in provinces in southern Vietnam. The results of this study showed that dioxin contamination in soil and sediment is higher than normal and identified specific US bases as hot spots (797 pg/g TCDD in Bien Hoa, 227 pg/g TCDD in Da Nang and 194 pg/g TCDD in Phu Cat) [26,27]. In 2001, a Japanese medical research team initiated a study concerning the human impact of herbicide spraying.…”

Section: Discussionmentioning

confidence: 99%

A GIS study of dioxin contamination in a Vietnamese region sprayed with herbicide

Nhu

Environ Health Prev Med

Naganuma

et al. 2009

Objectives The American-Vietnam War ended over 35 years ago, but dioxins still remain in human tissue and Vietnam's environment. The main objective of this study was to assess the correlation between dioxin concentration in soil, sediment and breast milk in one of the areas sprayed with herbicide, namely Cam Chinh commune, Quang Tri province, using a geographic information system (GIS). Methods The concentration of polychlorinated dibenzop-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in soil, sediment and breast milk samples was determined and the data analyzed using the geostatistical log-normal Kriging algorithm. Results The mean dioxin levels in soil and breast milk in the sprayed area were significantly higher than those in the non-sprayed area. The distribution pattern of PCDDs and PCDFs in soil was different, and there were no significant correlations between the estimated dioxin levels in soil obtained by the Kriging method and those in breast milk. Conclusions The possibility remains that another exposure route, such as exposure to herbicides used during the Vietnam War, might affect dioxin levels in breast milk, although more soil data are needed to make more reliable geographical estimations.

“…Dwernychuk et al (2002) found elevated levels of dioxins in soil, fish, duck, pooled human blood, and breast milk in regions close to former U.S. air bases. They theorized that high dioxin concentrations remained in the soil at former U.S. air bases, where the herbicide was stored, used, and accidentally spilled (Dwernychuk et al, 2005). These areas are called dioxin hotspots, with the three most contaminated air bases located in Bien Hoa, Da Nang, and Phu Cat (Dwernychuk et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Levels of polychlorinated dibenzodioxins and polychlorinated dibenzofurans in breast milk samples from three dioxin-contaminated hotspots of Vietnam

Manh

Science of The Total Environment

Okamoto

et al. 2015

We determined polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in breast milk of 143 primiparae living around the three most dioxin-contaminated areas of Vietnam. The women sampled lived in the vicinity of former U.S. air bases at Bien Hoa (n = 51), Phu Cat (n = 23), and Da Nang (n = 69), which are known as dioxin hotspots. Breast milk samples from Bien Hoa City, where residents live very close to the air base, showed high levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), with 18% of the samples containing >5 pg TCDD/g lipid. However, Phu Cat residents lived far from the air base and their samples showed lower TCDD levels, with none containing >5 pg TCDD/g lipid. In Da Nang, TCDD levels in mothers from Thanh Khe (close to the air base, n = 43) were significantly higher than those in mothers from Son Tra (far from the air base, n = 26), but not other PCDD and PCDF (PCDD/F) congeners. Although TCDD levels in Bien Hoa were highest among these hotspots, levels of other PCDD/F congeners as well as the geometric mean concentration of total PCDD/F level in Bien Hoa (9.3 pg toxic equivalents [TEQ]/g lipid) was significantly lower than the level observed in Phu Cat (14.1 pg TEQ/g lipid), Thanh Khe (14.3 pg TEQ/g lipid), and Son Tra (13.9 pg TEQ/g lipid). Our findings indicated that residents living close to former U.S. air bases were exposed to elevated levels of TCDD, but not of other PCDD/F congeners.