Mercury content of hair in different populations relative to fish consumption

Fish, rice, and human hair mercury concentrations and health risks in typical Hg-contaminated areas and fish-rich areas, China

Human exposure to methylmercury (MeHg) from consuming contaminated fish has been a major concern for decades. Besides, human MeHg exposure through rice consumption has been recently found to be important in some Asian countries. China is the largest country on mercury (Hg) production, consumption, and anthropogenic emission. However, the health risks of human Hg exposure are not fully understood. A total of 624 fish, 299 rice, and 994 human hair samples were collected from typical Hg-contaminated areas and major fish-rich areas to assess the health risks from human Hg exposure in China. Fish and rice samples showed relatively low Hg levels, except the rice in the Wanshan Hg mining area (WMMA). Human hair total Hg (THg) and MeHg concentrations were significantly elevated in WMMA, Zhoushan (ZS), Xiamen (XM), Qingdao (QD), and zinc smelting area (ZSA), and 85% of hair samples in WMMA, 62% in ZS, 40% in XM, 26% in QD, and 17% in ZSA had THg concentrations exceeding the limit set by the USEPA (1 μg/g). Rice consumption was the main pathway (>85%) for human MeHg exposure in the studied Hg-contaminated areas. Meanwhile, fish was the primary human MeHg exposure source (>85%) in coastal cities. Therefore, soil remediation in typical Hg-contaminated areas and scientific guidance for fish consumption in coastal provinces are urgently needed to reduce the health risks from human Hg exposure in China.

Mercury Exposure in Mother-Children Pairs in A Seafood Eating Population: Body Burden and Related Factors

Background: Mercury is a neurotoxin that affects neurodevelopment in children; however, its association at the lowest concentration is not clear. The main objective of this study is to measure and evaluate mercury concentrations in mother–child pairs and its association demographics, lifestyle, and dietary factors within the Pacific Island Families living in Auckland, New Zealand. Methods: Mercury exposure was assessed in a sub-sample of mother–child pairs who were a part of the Pacific Island Families birth cohort, in Auckland, New Zealand at the 6-year phase. Hair samples were collected from both mothers and their children to determine mercury concentrations. Total mercury was measured using inductively coupled plasma mass spectrometry for hair samples. An interviewer-based reliable food frequency questionnaire (FFQ) examined the frequency of seafood by all the participants. Other variables such as sociodemographic (ethnicity and gender), lifestyle factors (income, education, and smoking status) and health outcomes (child behaviour and obesity) were also collected. Results: In this study, 41% of both mothers and their children had mercury concentrations above the US Environmental Protection Agency (EPA) recommended value of 1 µg/g. Most of the participants ate fish 3 or more times a week. A significant correlation was observed between mother and child hair mercury concentrations (Spearman Rho 0.79 (95% confidence interval (CI): 0.65, 0.88)). Conclusions: Mercury levels in children can be affected by their mothers’ levels due to similar eating patterns.

Determination of Mercury Daily Intake and Hair-to-Blood Mercury Concentration Ratio in People Resident of the Coast of the Persian Gulf, Iran

The objectives of this study were to understand the mercury daily intake and hair-to-blood mercury ratio in fishermen and non-fishermen families in the coast of the Persian Gulf in Iran. The mean mercury concentration in the hair of fishermen and non-fishermen families was 5.76 and 2.27 μg/g, respectively. The mean mercury concentrations of RBCs were obtained for fishermen families and non-fishermen families: 35.96 and 17.18 μg/L, respectively. Hair mercury concentrations in 17% of people were higher than 10 μg/g, the No Observed Adverse Effects Level set by the World Health Organization. 78% of people had a blood mercury value > 5.8 μg/L, the standard level set by the U.S. Environmental Protection Agency. A significant correlation (r = 0.94, p = 0.000) was seen between log hair and RBCs mercury concentrations. The mean mercury daily intake for fishermen and non-fishermen families was 0.42 and 0.20 µg/kg BW per day, respectively. The mean mercury daily intake of fishermen families was higher than the provisional tolerable daily intake (0.23 µg/kg BW per day) suggested by the Joint Expert Committee on Food Additives. Mercury daily intake significantly correlated with fish consumption (r = 0.50, p = 0.000) and log hair mercury (r = 0.88, p = 0.000). The total mean of hair-to-blood mercury concentration ratio was 306. We conclude that the use of mercury concentrations in the hair and RBCs could have been suitable biomarkers for predicting mercury exposure of people with a high rate of fish consumption.

Topical melatonin for treatment of androgenetic alopecia

BACKGROUND

In the search for alternative agents to oral finasteride and topical minoxidil for the treatment of androgenetic alopecia (AGA), melatonin, a potent antioxidant and growth modulator, was identified as a promising candidate based on in vitro and in vivo studies.

MATERIALS AND METHODS

One pharmacodynamic study on topical application of melatonin and four clinical pre-post studies were performed in patients with androgenetic alopecia or general hair loss and evaluated by standardised questionnaires, TrichoScan, 60-second hair count test and hair pull test.

RESULTS

FIVE CLINICAL STUDIES SHOWED POSITIVE EFFECTS OF A TOPICAL MELATONIN SOLUTION IN THE TREATMENT OF AGA IN MEN AND WOMEN WHILE SHOWING GOOD TOLERABILITY: (1) Pharmacodynamics under once-daily topical application in the evening showed no significant influence on endogenous serum melatonin levels. (2) An observational study involving 30 men and women showed a significant reduction in the degree of severity of alopecia after 30 and 90 days (P < 0.001) based on questionnaires completed by investigators and patients. (3) Using a digital software-supported epiluminescence technique (TrichoScan) in 35 men with AGA, after 3 and 6 months in 54.8% to 58.1% of the patients a significant increase of hair density of 29% and 41%, respectively was measured (M0: 123/cm(2); M3: 159/cm(2); M6: 173/cm(2);) (P < 0,001). (4) In 60 men and women with hair loss, a significant reduction in hair loss was observed in women, while hair loss in men remained constant (P < 0.001). (5) In a large, 3-month, multi-center study with more than 1800 volunteers at 200 centers, the percentage of patients with a 2- to 3-fold positive hair-pull test decreased from 61.6% to 7.8%, while the percentage of patients with a negative hair-pull test increased from 12.2.% to 61.5% (P < 0.001). In addition, a decrease in seborrhea and seborrheic dermatitis of the scalp was observed.

CONCLUSIONS

Since safety and tolerability in all of the studies was good, the topical application of a cosmetic melatonin solution can be considered as a treatment option in androgenetic alopecia.

Differentiating inbred mouse strains from each other and those with single gene mutations using hair proteomics

Mutant laboratory mice with distinctive hair phenotypes are useful for identifying genes responsible for hair diseases. The work presented here demonstrates that shotgun proteomic profiling can distinguish hair shafts from different inbred mouse strains. For this purpose, analyzing the total hair shaft provided better discrimination than analyzing the isolated solubilized and particulate (cross-linked) fractions. Over 100 proteins exhibited significant differences among the 11 strains and 5 mutant stocks across the wide spectrum of strains surveyed. Effects on the profile of single gene mutations causing hair shaft defects were profound. Since the hair shaft provides a discrete sampling of the species proteome, with constituents serving important functions in epidermal appendages and throughout the body, this work provides a foundation for non-invasive diagnosis of genetic diseases of hair and perhaps other tissues.

Mercury (Hg) burden in children: the impact of dental amalgam

The risks and benefits of using mercury (Hg) in dental amalgam have long been debated. This study was designed to estimate Hg body burden and its association with dental amalgam fillings in 182 children (ages: 5-15 years) living in Taif City. Hg was measured in urine (UHg), hair (HHg) and toenails (NHg) by the Atomic Absorption Spectrophotometer with Vapor Generator Accessory system. Urinary Hg levels were calculated as both micrograms per gram creatinine (μg/g creatinine) and micrograms per liter (μg/L). We found that children with amalgam fillings (N=106) had significantly higher UHg-C levels than children without (N=76), with means of 3.763 μg/g creatinine versus 3.457 μg/g creatinine, respectively (P=0.019). The results were similar for UHg (P=0.01). A similar pattern was also seen for HHg, with means of 0.614 μg/g (N=97) for children with amalgam versus 0.242 μg/g (N=74) for those without amalgam fillings (P=0). Although the mean NHg was higher in children without amalgam (0.222 μg/g, N=61) versus those with (0.163 μg/g, N=101), the relationship was not significant (P=0.069). After adjusting for many confounders, the multiple logistic regression model revealed that the levels of UHg-C and HHg were 2.047 and 5.396 times higher, respectively, in children with dental amalgam compared to those without (P<0.01). In contrast, a significant inverse relationship was seen between NHg levels and dental amalgam fillings (P=0.003). Despite the controversy surrounding the health impact of dental amalgam, this study showed some evidence that amalgam-associated Hg exposure might be related with symptoms of oral health, such as aphthous ulcer, white patches, and a burning-mouth sensation. Further studies are needed to reproduce these findings. The present study showed that significant numbers of children with or without amalgam had Hg levels exceeding the acceptable reference limits. The detrimental neurobehavioral and/or nephrotoxic effects of such an increased Hg on children should be a cause of concern, and further investigation is warranted. Our results are alarming and indicate an urgent need for biomonitoring and assessment of exposure. Changes in dental practices involving amalgam, especially for children, are highly recommended in order to avoid unnecessary exposure to Hg.

Bacterial deposition of gold on hair: archeological, forensic and toxicological implications

Background

Trace metal analyses in hair are used in archeological, forensic and toxicological investigations as proxies for metabolic processes. We show metallophilic bacteria mediating the deposition of gold (Au), used as tracer for microbial activity in hair post mortem after burial, affecting results of such analyses.

Methodology/Principal Findings

Human hair was incubated for up to six months in auriferous soils, in natural soil columns (Experiment 1), soils amended with mobile Au(III)-complexes (Experiment 2) and the Au-precipitating bacterium Cupriavidus metallidurans (Experiment 3), in peptone-meat-extract (PME) medium in a culture of C. metallidurans amended with Au(III)-complexes (Experiment 4), and in non-auriferous soil (Experiment 5). Hair samples were analyzed using scanning electron microscopy, confocal microscopy and inductively coupled plasma-mass spectrometry. In Experiments 1–4 the Au content increased with time (P = 0.038). The largest increase was observed in Experiment 4 vs. Experiment 1 (mean = 1188 vs. 161 µg Kg⁻¹, Fisher's least significance 0.001). The sulfur content, a proxy for hair metabolism, remained unchanged. Notably, the ratios of Au-to-S increased with time (linear trend P = 0.02) and with added Au and bacteria (linear trend, P = 0.005), demonstrating that larger populations of Au-precipitating bacteria and increased availability of Au increased the deposition of Au on the hair.

Conclusion/Significance

Interactions of soil biota with hair post mortem may distort results of hair analyses, implying that metal content, microbial activities and the duration of burial must be considered in the interpretation of results of archeological, forensic and toxicological hair analyses, which have hitherto been proxies for pre-mortem metabolic processes.