Tracking Declines in Mercury Exposure in the New York City Adult Population, 2004-2014

A rapid method for the determination of methylmercury and inorganic mercury species in whole blood by liquid chromatography with detection using vapor generation ICP-MS/MS

Speciation methods provide a more detailed picture regarding human exposure to toxic metals/metalloids and their effects on human health. The toxicity of methylmercury (MeHg) differs considerably from inorganic mercury (iHg), such that their separation and quantification in whole blood is helpful in identifying sources and possible pathways of exposure. Liquid chromatography (LC) has several advantages over gas chromatography (GC) for the separation of iHg from MeHg due to the former's compatibility with uptake rates of common nebulizer systems used with ICP-MS and the latter's requirement for a derivatization step to produce gaseous Hg species for an effective separation. Here we report an improved method that was developed to separate and quantify MeHg and iHg species in whole blood using isocratic LC elution with determination by vapor generation (VG) coupled with ICP-MS/MS. Chromatographic separation of MeHg and iHg is achieved in ∼4 minutes on a C8 reversed phase column. In those rare cases where there may be human exposure to ethylmercury (EtHg), or where a certified reference material (CRM) is known to contain EtHg (e.g., NIST SRM 955c), all three Hg species can be separated by extending the LC elution time to 8 minutes. Adding VG post column boosts the signal-to-noise ratio, and lowers the LOD. With optimized sample preparation, the LC-VG-ICP-MS/MS method LOD for both iHg and MeHg is 0.2 μg L-1. Method validation was conducted using NIST SRM 955c Toxic Metals in Caprine Blood and NIST SRM 955d Toxic Elements and Metabolites in Frozen Human Blood. Additional validation data were generated using archived blood reference materials from multiple Proficiency Testing programs and External Quality Assessment schemes. Blood-based quality control materials, previously analyzed for Hg species using isotope dilution with GC coupled to ICP-MS, were provided by the US CDC.

Trends of hair Hg accumulation in reproductive-age women living in Central Russia and the calculated costs of Hg-induced IQ loss in the period between 2005 and 2021

The objective of the present study was to retrospectively evaluate hair mercury (Hg) content in reproductive-age women living in Central Russia (Moscow and Moscow region), and to calculate the potential costs of the potential Hg-induced IQ loss in a hypothetical national birth cohort.

MATERIALS AND METHODS

A total of 36,263 occupationally non-exposed women aged between 20 and 40 years living in Moscow (n = 30,626) or Moscow region (n = 5637) in the period between 2005 and 2021 participated in this study. Hair Hg content was evaluated with inductively coupled plasma-mass spectrometry (ICP-MS). Hair Hg levels in reproductive-age women were used for assessment of the potential IQ loss and its costs.

RESULTS

The results demonstrate that hair Hg content in the periods between 2010 and 2015, and 2016-2021 was significantly lower than that in 2005-2009 by 26 % and 51 %, respectively. The highest hair Hg level was observed in women in 2005 (0.855 µg/g), being more than 2.5-fold higher than the lowest value observed in 2020 (0.328 µg/g). Multiple regression analysis revealed a significant inverse association between the year of analysis and hair Hg content (β = -0.288; p < 0.001). The calculations demonstrate that in 2005 the costs of IQ loss in children exceeded 1.0 (1.6) billion USD, whereas in 2020 the costs of IQ loss accounted to approximately 0.15 (0.28) billion USD.

CONCLUSION

Taken together, our data demonstrate that Hg accumulation in reproductive-age women reduced significantly in Russia from 2005 to 2021 resulting in predicted economic benefits by decreasing the costs of Hg-induced IQ loss.

Global Human Threat: The Potential Synergism between Mercury Intoxication and COVID-19

The COVID-19 pandemic affected billions of people worldwide, and exposure to toxic metals has emerged as an important risk factor for COVID-19 severity. Mercury is currently ranked as the third toxic substance of global concern for human health, and its emissions to the atmosphere have increased globally. Both COVID-19 and mercury exposure present a high prevalence in similar regions: East and Southeast Asia, South America and Sub-Saharan Africa. Since both factors represent a multiorgan threat, a possible synergism could be exacerbating health injuries. Here, we discuss key aspects in mercury intoxication and SARS-CoV-2 infection, describing the similarities shared in clinical manifestations (especially neurological and cardiovascular outcomes), molecular mechanisms (with a hypothesis in the renin-angiotensin system) and genetic susceptibility (mainly by apolipoprotein E, paraoxonase 1 and glutathione family genes). Literature gaps on epidemiological data are also highlighted, considering the coincident prevalence. Furthermore, based on the most recent evidence, we justify and propose a case study of the vulnerable populations of the Brazilian Amazon. An understanding of the possible adverse synergism between these two factors is crucial and urgent for developing future strategies for reducing disparities between developed and underdeveloped/developing countries and the proper management of their vulnerable populations, particularly considering the long-term sequelae of COVID-19.

Monthly variations in mercury exposure of school children and adults in an industrial area of southwestern China

Recent studies have shown that rice consumption can be the major pathway for human methylmercury (MeHg) exposure in inland China. However, few studies have considered the susceptible population of school children's exposure through rice ingestion. In this study, monthly variations in total Hg (THg)/MeHg concentrations in rice, fish, hair, and urine samples were studied to evaluate the Hg (both THg and MeHg) exposure in Guiyang, a typical industrial area with high anthropogenic emission of Hg. A total of 17 primary school (school A) students, 29 middle school (school B) students, and 46 guardians participated in this study for one year. Hair THg, hair MeHg, and urine THg concentrations ranged from 355-413 ng g^-1, 213-236 ng g^-1, and 469-518 ng g^-1 Creatinine (ng·g^-1 Cr), respectively, and no significant differences were observed between different genders and age groups. Hair and urine Hg concentrations showed slightly higher values in the cold season (October to February) than the hot season (March to September), but without significant difference. High monthly variability of individual hair and urine Hg concentrations suggested that long-term study could effectively decrease the uncertainty. The school students showed significantly higher urine THg concentrations than adults due to children's unique physiological structure and behaviors. Probable daily intake (PDI) of MeHg via rice and fish ingestion averaged at 0.0091, 0.0090, and 0.0079 μg kg^-1 d^-1 for school A students, school B students, and their guardians, respectively, which means that 86%, 84%, and 87% of the PDI were originated from rice ingestion, respectively. Therefore, more attention should be paid to children as a susceptible population. The results indicated low risk of Hg exposure via rice and fish consumption for urban residents in a Chinese industrial city.

Mercury pollution in modern times and its socio-medical consequences

Mercury plays a critical role in serious health problems due to environmental or occupational exposures. Aquatic ecosystems are an essential component of the global biogeochemical cycle of mercury, as inorganic mercury can be converted to toxic methyl mercury in these environments and reemissions of elemental mercury rival anthropogenic mercury releases on a global scale. The history of the Minamata disease, a typical example of industrial pollution, has shown how corporate secrecy and ignorance on part of the health authorities may influence the devastating spread of environmental contamination and the progress of disease. While the Minamata Convention, in place since 2017, is aiming to lower mercury exposure and to prevent adverse effects, there are still knowledge gaps in the areas of global environmental mercury exposure. Areas of uncertainty in the global biogeochemical cycle of mercury include oxidation processes in the atmosphere, land-atmosphere and ocean-atmosphere cycling, and methylation processes in the ocean. Pollution related to climate change (especially in boreal and arctic regions), bioaccumulation and biomagnification of methyl mercury in the food chain, especially in fish and marine mammals, needs to be addressed in more detail. Information is lacking on numerous hidden contaminant exposures i.e. from globally applied traditional medicine, mercury containing skin creams and soaps, dental amalgam, ethyl mercury containing vaccines and latex paint additives, as well as on mercury releases from power plants, e-waste/fluorescent lamps, wildfire emissions, and global artisanal small-scale gold mining activities. Mercury occurs in various forms with different levels of toxicity. While much is already known and documented on the health effects of mercury, present knowledge and translation into preventive actions is still incomplete. Risks for long term health effects trough prolonged low dose exposure and trough cumulative exposures of various mercury forms should be further addressed. Preventive actions should include adequate human biomonitoring programs. Research data should be translated swiftly into management tools for local policy makers and health professionals, also paying attention at the major differences in mercury contamination across the globe.