Total blood mercury and its determinants in New Zealand children and adults

Blood mercury concentrations in preschool children and potential risk factors in São Paulo, Brazil

Environmental exposure of preschool children to mercury can elevate blood mercury levels (BML) and negatively affect their health. This study aimed to determine BML in preschool children from Brazil's largest city and explore potential associated risk factors. Blood samples were collected in 2013 from 2436 children (age 1-5 years) attending 50 daycare centers (DCC) located in São Paulo, Brazil. Parents or guardians answered questionnaires collecting information on sociodemographics and potential risk factors. BML was determined by Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) and categorized using a cutoff point of 2.77 μg L⁻1, corresponding to the 75th percentile. Multiple logistic regression was performed (p < 0.05). Data were georeferenced and associations with air pollution, wind frequency and direction were evaluated. The results showed a geometric mean for BML of 1.65 μg L⁻1 (95% CI: 1.60-1.70), arithmetic mean of 2.15 μg L⁻1 (95% CI: 2.09-2.22), 75th percentile of 2.77 μg L⁻1 (95% CI: 2.67-2.91) and 95th percentile of 5.51 μg L⁻1 (95% CI: 5.18-5.92). DCCs located in the Northwest and East zones (p < 0.001) and fish consumption in the past two days (p = 0.04) were associated with high BML. The elevated BML observed in children living in the eastern zone might be attributed to the southeasterly winds passing through a petrochemical complex located nearby. The 95th percentile of BML in this study exceeded the U.S. 95th percentile by five times. BML in São Paulo preschool children was associated with individual and environmental risk factors. This finding highlights the need to identify and control hot spots in São Paulo, Brazil, especially in peripheral and surrounding areas, where individuals are more vulnerable. Further research is needed in Latin America to identify additional sources of urban environmental mercury exposure and guide interventions for protecting the environment and safeguarding children's health.

Factors associated with blood mercury concentrations and their interactions with three glutathione S-transferase genes (GSTT1, GSTM1, and GSTP1): an exposure assessment study of typically developing Jamaican children

BACKGROUND

Jamaican soil is abundant in heavy metals including mercury (Hg). Due to availability and ease of access, fish is a traditional dietary component in Jamaica and a significant source of Hg exposure. Mercury is a xenobiotic and known neuro-toxicant that affects children's neurodevelopment. Human glutathione S-transferase (GST) genes, including GSTT1, GSTM1, and GSTP1, affect Hg conjugation and elimination mechanisms.

METHODS

In this exposure assessment study we used data from 375 typically developing (TD) 2-8-year-old Jamaican children to explore the association between environmental Hg exposure, GST genes, and their interaction effects on blood Hg concentrations (BHgCs). We used multivariable general linear models (GLMs).

RESULTS

We identified the child's age, consumption of saltwater fish, canned fish (sardine, mackerel), string beans, grain, and starches (pasta, macaroni, noodles) as the environmental factors significantly associated with BHgCs (all P < 0.05). A significant interaction between consumption of canned fish (sardine, mackerel) and GSTP1 in relation to BHgC using either a co-dominant or recessive genetic model (overall interaction P = 0.01 and P < 0.01, respectively) indicated that consumption of canned fish (sardine, mackerel) was significantly associated with higher mean BHgC only among children with the GSTP1 Ile105Val, Ile/Ile [Ratio of mean Hg (95% CI) = 1.59 (1.09, 2.32), P = 0.02] and Ile/Val [Ratio of mean Hg (95% CI) = 1.46 (1.12, 1.91), P = 0.01] genotypes.

CONCLUSIONS

Since this is the first study from Jamaica to report these findings, replication in other populations is recommended.

Lead, cadmium, and mercury blood levels in schoolchildren in southern Sweden: Time trends over the last decades

To prevent diseases arising from exposure to toxic metals, more knowledge about their temporal changes is needed, especially in children, the most vulnerable group. This study follows temporal changes in blood lead (BPb), mercury (BHg) and cadmium (BCd) levels in schoolchildren (8-11 years old) from two cities in southern Sweden. One blood sample per 773 children was used for time trend analyses between 2007 and 2022. One further blood sample re-sampled after 2 years, were used to assess intra-individual time trends of BPb (n = 377), BCd (n = 102) and BHg (n = 53) between 1979 and 2019. Geometric mean (range) of BPb, BCd and BHg concentrations during 2007-2022 was 9.9 (2.3-59), 0.09 (0.03-0.34) and 0.73 (0.02-8.2) μg/L, respectively. Living close to a Pb smelter resulted in higher levels of all three metals compared with living in the city or rural area. Annually, the concentrations clearly decreased for BPb (-4.9%, p < 0.001) and weakly for BCd (-0.6%, p = 0.013), while BHg slightly increased (+1.4%, p = 0.029). When stratified by residential area, the decrease of BCd and increase of BHg were significant only in the urban area (-1.8% and +2.8%, respectively; p < 0.01). The BPb decrease rate was the highest in the urban area followed by the rural and Pb smelter areas (-5.8% > -4.5% > -3.9%; p < 0.001). For children re-analysed during 1979-2019, a significant decrease was observed only for BPb (-6.8%; p < 0.001), with a 2% higher decrease rate in the period before than after the Pb-gasoline ban in 1994. The preventive measures against Pb pollution are reflected in the constant decrease of BPb levels over time. However, the area close to a Pb smelter, as indicated by a slower Pb decrease rate, might need further and stricter preventive measures. Exposure to Hg and Cd was low, however, the slight increase in BHg and only a minor decrease in BCd, indicate the need for continuous biomonitoring of children.

Mercury chloride activates the IFNγ-IRF1 signaling in myeloid progenitors and promotes monopoiesis in mice

Inorganic mercury (Hg2+) is a highly toxic heavy metal in the environment. To date, the impacts of Hg2+ on the development of monocytes, or monopoiesis, have not been fully addressed. The aim of the present study was to investigate the impact of Hg2+ on monopoiesis. In this study, we treated B10.S mice and DBA/2 mice with 10 μM or 50 μM HgCl2 via drinking water for 4 wk, and we then evaluated the development of monocytes. Treatment with 50 μM HgCl2, but not 10 μM HgCl2, increased the number of monocytes in the blood, spleen and bone marrow (BM) of B10.S mice. Accordingly, treatment with 50 μM HgCl2, but not 10 μM HgCl2, increased the number of common myeloid progenitors (CMP) and granulocyte-macrophage progenitors (GMP) in the BM. Functional analyses indicated that treatment with 50 μM HgCl2 promoted the differentiation of CMP and GMP to monocytes in the BM of B10.S mice. Mechanistically, treatment with 50 μM HgCl2 induced the production of IFNγ, which activated the Jak1/3-STAT1/3-IRF1 signaling in CMP and GMP and enhanced their differentiation potential for monocytes in the BM, thus likely leading to increased number of mature monocytes in B10.S mice. Moreover, the increased monopoiesis by Hg2+ was associated with the increased inflammatory status in B10.S mice. In contrast, treatment with 50 μM HgCl2 did not impact the monopoiesis in DBA/2 mice. Our study reveals the impact of Hg on the development of monocytes.

Determinants affecting the blood mercury levels of preschool children in Shanghai, China: A cross-sectional study

Infants and children are vulnerable to mercury (Hg)-induced toxicity, which has detrimental effects on their neurological development. This study measured blood Hg levels (BMLs) and identified potential factors influencing BMLs, including demographic and socioeconomic factors, lifestyle, and daily dietary habits, among 0 to 7-year-old children in Shanghai. Our study recruited 1474 participants, comprising 784 boys and 690 girls. Basic demographic and lifestyle information were obtained and blood Hg were analyzed using the Direct Mercury Analyzer 80. The blood Hg concentrations of children in Shanghai ranged from 0.01 to 17.20 μg/L, with a median concentration of 1.34 μg/L. Older age, higher familial socioeconomic status, higher residential floors, and a higher frequency of consuming aquatic products, rice, vegetables, and formula milk were identified as risk factors. Other potential influencing factors including the mother's reproductive history (gravidity and parity), smoking (passive smoking), supplementation of fish oil and calcium need to be further investigated. These findings can be useful in establishing appropriate interventions to prevent children's high blood Hg concentrations in Shanghai and other similar metropolitan cities.

Occurrence and health implications of heavy metals in preschool children's clothing manufactured in four Asian regions

Clothing may be a potential contributor to body metal burden in children. However, available information on heavy metals in children's clothing is extremely limited and the associated health risks remain poorly understood. This study investigated the concentrations of Pb, Cd, Co, Zn, Cr, As, Cu and Ni in new preschool children's clothing manufactured in four Asian regions. The children's clothing had higher levels of Ni and Cr but lower levels of Pb and Cd in comparison to the concentrations reported in other textile products. The concentrations of Cd were higher in the black clothing than those in the white and color samples. The non-cotton samples contained higher Co concentrations. The Pb concentrations in the samples manufactured in China were significantly higher than those in the other three regions. We estimated the dermal exposure doses for these metals and calculated the associated risks. The results indicated that the health risks from exposure to these metals in the children's clothing were acceptable. However, more research is required to investigate heavy metals and the associated risks in child clothing due to the increasing complexity of their materials and manufacturing processes.

Trace elements in whole blood in the general population in Trøndelag County, Norway: The HUNT3 Survey

BACKGROUND

Biomonitoring of a cohort within a large health survey can provide reliable information on trace element status. The main aims of this study were 1) to determine the concentrations of 28 trace elements in whole blood samples from the general population of the Nord-Trøndelag region, Norway, and 2) to investigate how trace element concentrations vary with geographical area, lifestyle, and socio-demographic factors.

METHODS

Whole blood samples were collected in the third survey of the Trøndelag Health Survey (HUNT3), a large population-based study in Norway. In total, 1011 whole blood samples from individuals aged 20-91 years were analyzed using high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS). We compared trace element concentrations (As, B, Be, Br, Ca, Cd, Cr, Cs, Cu, Ga, Au, In, Fe, Pb, Hg, Tl, Mg, Mn, Mo, Ni, Rb, Sc, Se, Ag, Sr, Sn, W and Zn) between three geographical areas (coastal, fjord/town, inland/mountain) using multivariable linear regression and assessed differences in trace element concentrations with socio-demographic and lifestyle factors using general linear models.

RESULTS

Trace element concentrations were generally comparable to levels reported in other recent studies and suggest low exposure to toxic trace elements in the region. We found geographical differences in concentrations of 19 trace elements. As, Br, Hg, and Se concentrations were higher on the coast compared to the fjord/town and inland/mountain areas, suggesting that the marine environment is an important source of exposure for these trace elements. In addition, socio-demographic and lifestyle characteristics, particularly age and sex, were associated with differences in trace element concentrations.

CONCLUSIONS

We report concentrations of 28 trace elements in the general population of a rural region with low exposure to pollution. Whole blood concentrations of trace elements varied with geographical area, the participants' lifestyle, and socio-demographic characteristics, highlighting the importance of considering these factors when evaluating trace element status in a population.