Mercury Concentrations Research Articles

Quarter century of mercury litterfall at a coniferous forest responding to climate change, Central Europe.

This work evaluated the 25-year-long trends (1994-2018) in mercury (Hg) concentrations and fluxes in spruce litterfall at a forest research plot Načetín (NAC) recovering from acidic deposition in the Ore Mountains, Czech Republic. The mean litterfall Hg deposition averaged 51 ± 18µgm-2year-1, which has been the highest litterfall Hg deposition reported up to date on the European continent. In contrast, the wet deposition (2017-2019) was an order of magnitude lower averaging at 2.5 ± 1.5µgm-2year-1. All the spruce litterfall components bark, twigs, needles, cones, and a mixture of unidentified fragments had elevated mean Hg concentrations relative to background sites averaging 256 ± 77, 234 ± 62, 119 ± 23, 95 ± 14, and 44 ± 15µg kg-1, respectively. Elevated litterfall Hg deposition and concentrations were attributed to the nearby local Hg emission source-coal-fired power plants. Temporally, the decrease of Czech Hg emissions since the 1990s was reflected by the decreasing trend of Hg concentrations in litterfall bark, cones, and twigs, while in needles and other material, Hg increased but insignificantly. Total litterfall ratios of Hg/C, Hg/N, and Hg/S were lower than those in soil O horizons averaging at 0.23 ± 0.04, 9.5 ± 2.0, and 170 ± 37μgg-1, respectively. Since the beginning of monitoring, total litterfall Hg/C exhibited no trend, Hg/N decreased, and Hg/S increased. The litterfall biomass deposition averaging at 469 ± 176gm-2year-1 increased through time resulting in an increased Hg litterfall deposition at NAC by 1.1µgm-2year-1 despite the decreases in Czech Hg emissions. Peaks of annual litterfall Hg deposition up to 96µgm-2year-1 at NAC during the 25years of monitoring resulted from weather extremes such as rime-snow accumulation, wind gusts, droughts, and insect infestation, which all significantly affected the annual biomass deposition. Based on our observations, further increases in biomass and litterfall Hg deposition rates can be expected due to the onset of bark beetle infestation and the increasing number of droughts caused by climate change.

Assessment of Mercury Contamination in Water and Soil from Informal Artisanal Gold Mining: Implications for Environmental and Human Health in Darmali Area, Sudan

Mercury contamination stemming from artisanal and small-scale gold mining (ASGM) operations poses significant environmental and health concerns. This study focuses on the Darmali area in River Nile State, Sudan, where the reprocessing of amalgamation tailings has led to mercury contamination. This study assessed the mercury content in soil and tailings samples, as well as in tap and groundwater, to evaluate the human health risks from ASGM activities and assess contamination levels within the study area. Soil and water samples were collected from various locations, including agricultural, residential, and tailings sites, as well as groundwater and tap water from the Nile. Mercury analysis was conducted using MA-3000 (NIC), and geo-accumulation index analysis revealed extreme pollution levels in areas with tailings and moderate pollution levels in agricultural and residential areas. Hazard quotients were applied to assess health risks, with inhalation of mercury vapor identified as the primary exposure route. The results indicated that tailings pose significant health risks, particularly for children, while water samples and soil from agricultural and residential areas did not pose significant risks. These findings underscore the urgent need for authorities and local communities to address mercury contamination by removing and treating tailings from affected areas to mitigate health risks.

Atmospheric gaseous mercury and associated health risk assessment in the economic capital of India.

Mercury cycling in coastal metropolitan areas on the west coast of India becomes complex due to the combined effects of both intensive domestic anthropogenic emissions and marine air masses. The present study is based on yearlong data of continuous measurements of gaseous elemental mercury (GEM) concentration concurrent with meteorological parameters and some air pollutants at a coastal urban site in Mumbai, on the west coast of India, for the first time. The concentration of GEM was found in a range between 2.2 and 12.3ng/m3, with a mean of 3.1 ± 1.1ng/m3, which was significantly higher than the continental background values in the Northern Hemisphere (~ 1.5ng/m3). Unlike particulates, GEM starts increasing post-winter to peak during the monsoon and decrease towards winter. July had the highest concentration of GEM followed by October, and a minimum in January. GEM exhibited a distinct diurnal cycle, mainly with a broad peak in the early morning, a narrow one by nightfall, and a minimum in the afternoon. The peaks and their timing suggest the origin of urban mobility and the start of local activities. A positive correlation between SO2, PM2.5, temperature, relative humidity, and GEM indicates that emissions from local industrial plants in the Mumbai coastal area. Principal component analysis (PCA) and cluster analysis (CA) confirm this fact. Monthly back trajectory analysis showed that air mass flows are predominantly from the Arabian Sea and local human activities. Assessment of human health risks by USEPA model reveals that the hazardous quotient, HQ < 1, implies negligible carcinogenic risk. GEM observations in Mumbai during the study period are below the World Health Organization's (WHO) safe limit (200ng/m3) for long-term inhalation.

Comparison of carbon, nitrogen, and oxygen stable isotope ratios and mercury concentrations in muscle tissues of five beaked whale species and sperm whales stranded in Hokkaido, Japan

ABSTRACT We studied δ 13C, δ 15N and δ 18O values, and total mercury (THg) concentrations in muscle samples from deep-sea predators – five beaked whale species and sperm whales – stranded along the coast of Hokkaido, in the north of Japan in 2010 and 2019. The δ 13C, δ 15N and δ 18O values, THg concentrations, and body length (BL) of Stejneger’s beaked whales were similar to those of Hubbs’ beaked whales, which belong to the same genus. In contrast, δ 13C values, THg concentrations, and BL of Sato’s beaked whales were markedly different from those of Baird’s beaked whales, which belong to the same genus. Stejneger’s and Hubbs’ beaked whales living around Hokkaido may compete in their ecological niches, whereas Sato’s and Baird’s beaked whales may segregate their ecological niches. Although Cuvier’s beaked whales and sperm whales belong to different genera and their BLs were significantly different, their δ 13C and δ 15N values were similar, probably because they can dive and stay in deeper waters than other beaked whale species. The δ 13C values in combined samples from all whales increased with increasing BL, probably owing to the larger whale species’ dietary preference for squid. The δ 13C values in combined samples from all whales were positively correlated with THg concentrations, whereas the δ 15N values in the combined samples were negatively correlated. The δ 18O values in combined samples from most whales tended to be positively correlated with THg concentrations. These correlations may be explained by a higher THg load from deep-sea feeding than from pelagic feeding and by a feeding shift towards lower trophic levels.

Hydrology and oxygen addition drive nutrients, metals, and methylmercury cycling in a hypereutrophic water supply reservoir

Impaired water quality in Mediterranean climate reservoirs is mainly associated with eutrophication and internal nutrient loading. To improve water quality in hypereutrophic Hodges Reservoir, California, United States, a hypolimnetic oxygenation system (HOS), using pure oxygen gas, was implemented in 2020. This study encompasses 3 years of pre-oxygenation data (2017–2019) and 2 years of post-oxygenation data (2020–2021) to understand the cycling of nutrients, metals, and mercury in the reservoir. During the wet year of 2017, mildly reduced conditions lasted until mid-summer in the enlarged reservoir. Nutrients and metals were seen in the hypolimnion including ammonia (~2 mg-N/L), manganese (~0.5 mg/L), phosphate (~0.5 mg-P/L), and sulfide (~10 mg/L). Production of methylmercury (MeHg), an important bioaccumulative toxin, was favored from April to June with a hypolimnetic accumulation rate of around 200 ng/m2·d. In contrast, the dry year of 2018 exhibited higher hypolimnetic concentrations of ammonia (~4 mg-N/L), manganese (~1 mg/L), phosphate (&amp;gt;0.5 mg-P/L), and sulfide (&amp;gt;15 mg/L). The rapid onset of highly reduced conditions in 2018 corresponded with low MeHg hypolimnetic accumulation (~50 ng/m2·d). It seems that mildly reduced conditions were associated with higher MeHg accumulation, while sulfidic, reduced conditions impaired inorganic mercury bioavailability for MeHg production and/or promoted microbial demethylation. Sulfide also appeared to act as a sink for iron via FeS precipitation, and potentially for manganese via MnS precipitation or manganese coprecipitation with FeS. Mass flux estimates for 2017–2019 indicate that much of the nutrients that accumulated in the hypolimnion moved via turbulent diffusion into the epilimnion at loading rates far exceeding thresholds predicting eutrophic conditions. After oxygenation in 2020–2021, the reservoir water column was highly oxidized but showed a lack of thermal stratification, suggesting reservoir operations in combination with HOS implementation inadvertently mixed the water column in this relatively shallow reservoir. Post-oxygenation, concentrations of ammonia, phosphate, manganese, and mercury in bottom waters all decreased, likely in response to oxidized conditions. Oxygenated bottom waters exhibited elevated nitrate, a byproduct of ammonia nitrification, and iron, a byproduct of FeS oxidation, indicating a lake-wide response to oxygenation.

Concentrations, Sources, and Health Risk of Heavy Metals in Edible Parts of Broilers from Northeast of Algeria.

Heavy metals contamination of poultry products is a major concern for public health. This study aimed to determine the concentration of mercury (Hg), lead (Pb), and iron (Fe) in the edible parts of broilers, as well as in feed, drinking water, and litter as sources of contamination and to assess their possible human health risk in the province of Jijel (Northeast Algeria). The range of Hg, Pb, and Fe in edible parts were 0.004-0.007, 0.185-0.480, and 28.536-88.306mg/kg, respectively, and the difference in content was only significant (p < 0.05) for lead. Breast and thigh samples had Pb concentrations above the maximum limit. Spearman coefficient analysis revealed that most correlations were positive between metals detected in feed, water, and litter and those in the edible parts of broilers. But most of them were insignificant (p > 0.05). The estimated daily intake (EDI) values of examined metal exceeded the tolerable daily intake (PTDI). The target hazard quotients (THQ) and hazard index (HI) of all metals were lower than 1, suggesting no significant carcinogenic risks. The calculated incremental lifetime cancer risk (ILCR) of Pb was higher than 10-4 for men, women, and children, indicating the presence of carcinogenic risk. Considering the wide consumption of broiler meat, regular national monitoring of heavy metals in the broiler production chain is recommended to protect population health.

Distribution of mercury contamination on paddy fields in various levels of soil depth in gold mine area at Sub-District Hutabargot, Mandailing Natal Regency, Indonesia

Unauthorised Gold Mining in Mandailing Natal Regency could serious problems for the environment and human health. It is because waste from the amalgamation process contains mercury released into the waterways that are irrigation sources. The main damage impact from the mercury waste released into irrigation canals would be seen on the paddy field. For this reason, it is necerssary to tests and studies to see the contaminated level of mercury on paddy fields. This research was conducted from June to July 2023 in Sub-District Hutabargot, Mandailing Natal Regency by took soil sampling in the 0-10 cm, 11-20 cm, 21-20 cm, 31-40 cm, 41-50 cm, 51-60 cm, 61-70 cm, 71-80 cm, 81-90 cm, and 91-100 cm on soil depth in 7 sampling points. The resulting study obtained at least 170 amalgamation points that the waste released into the waters. The mercury content on the paddy soil in Sub-District Hutabargot which is irrigation irrigated by amalgamation process exceeding the threshold. There is an increase of mercury content in the 30 cm soil depth and then decreases with increasing soil depth. For a depth of more than 60 cm, the mercury content on the paddy soil is under the threshold.

Mercury Concentrations in Feathers of Albatrosses and Large Petrels at South Georgia: Contemporary Patterns and Comparisons with Past Decades

Mercury (Hg) is an environmental contaminant that can negatively impact the health of humans and wildlife. Albatrosses and large petrels show some of the highest levels of Hg contamination among birds, with potential repercussions for reproduction and survival. Here, body feather total Hg (THg) concentrations were determined in breeding adults of five species of albatrosses and large petrels in the foraging guild at South Georgia during the mid-2010s. We tested the effects of species, sex and trophic ecology (inferred from stable isotopes) on THg concentrations and compared our results with published values from past decades. Feather THg concentrations differed significantly among species (range: 1.9–49.6 µg g−1 dw), and were highest in wandering albatrosses Diomedea exulans, intermediate in black-browed albatrosses Thalassarche melanophris and northern giant petrels Macronectes halli, and lowest in southern giant petrels M. giganteus and white-chinned petrels Procellaria aequinoctialis. Females were more contaminated than males in all species, potentially due to differences in distributions and diet composition. Across species, THg concentrations were not correlated with feather δ13C or δ15N values, implying that species effects (e.g., breeding and moulting frequencies) may be more important than trophic effects in explaining feather THg concentrations in this foraging guild. Within species, the only significant correlation was between THg and δ13C in wandering albatrosses, which could reflect higher Hg exposure in subtropical waters. Comparisons with THg concentrations from past studies, which reflect contamination from 10 to > 60 years ago, revealed considerable annual variation and some evidence for increases over time for wandering and black-browed albatrosses since before 1950 and from the late 1980s, respectively.

Distribution and source of contamination of heavy metal mercury at paddy field in Mandailing Natal Regency, North Sumatera, Indonesia

Mandailing Natal Regency is administratively located in North Sumatera Province with 662,070 hectares width and a paddy field area of 40,051 hectares. Batang Gadis River stream is 180 KM long and became the source of livelihood for people in Mandailing Natal Regency as the source of drinking water, irrigation, and protein food source such as fish. Unlicensed Gold mining (PETI) occurred massively in Mandailing Natal Regency precisely at Sub-District Muara Sipongi, Sub-District Ulu Pungkut, Sub-District Huta Bargot, and Sub-District Naga Juang. The use of mercury for the amalgamation process in gold mining produces mercury waste which the run-off stream to the irrigation canals and at the end stream to Batang Gadis River Flow. This research conducted the distribution and source of contamination of heavy metal mercury at paddy fields in Mandailing Natal Regency, North Sumatera, Indonesia. The research was conducted to take soil sample analysis from paddy fields as much as 100 points from 20 paddy field locations near the amalgamation place or the water source for irrigation from Batang Gadis River that spread in five sub-districts. The soil sample analysis took for 25 cm depth. The results showed that the mercury concentration in all rice fields studied exceeded the quality standard threshold with the highest concentration found in Sub-District Naga Juang as much as 11.47 ppm followed by Sub-District Hutabargot with 10,77 ppm concentration. The factor that determines the paddy soil contamination by the mercury was the amalgamation waste which directly streams to irrigation canals compared with the paddy field with irrigation canals direct from the Batang Gadis River.

Baseline study for the total mercury determination in Yemeni fish

The high levels of mercury toxicity in humans make it necessary to monitor mercury levels in food, pharmaceuticals, and the environment to minimize human exposure. Between June 2020 and October 2021, researchers collected 240 fish samples from different locations along the Yemeni coast to evaluate mercury contamination. The Direct Mercury Analyzer was used to determine the concentration of mercury in each sample. To ensure method accuracy, a series of triplicate mercury concentration analyses were conducted. The samples ranged from 2 to 100 ng to determine linearity and repeatability i.e., within-day variation. The results showed a high level of precision, with a correlation coefficient of 0.9990 and a repeatability of 1.34 %–5.62 % RSD range. The method was also highly accurate, as the mercury recovery results from the contaminated fish samples ranged from 96.77 % to 105.14 %. The limits of detection and quantitation of mercury were 0.0015 ppm and 0.0049 ppm, respectively. This allowed the method to detect trace amounts of mercury in fish meat. Mercury concentration in the 240 fish samples did not exceed the FDA, but below the 0.5 ppm specified limit of YSMO.

The capacity of Plectranthus sp. to perform phytoremediation on heavy metal mercury (Hg) in the tailing of gold processing industries

Sludge (tailing), a waste product of the amalgamation process used in the mining of gold, contains a high concentration of the heavy metal mercury (Hg). It is well known that mercury builds up in large quantities in Plectranthus sp. herbaceous plants in the Pancurendang Village Small-Scale Gold Mining area. The study intends to: 1) quantify the amounts of mercury present in plant organs and media tailing during phytoremediation treatment; 2) examine the mechanisms and capacities of plant phytoremediation using values of the Biological Accumulation Coefficient (BAC), Biological Concentration Factor (BCF), and Translocation Factor (TF); and 3) determine the impact of percentage variations in tailing and time on Plectranthus sp.’s capacity to accumulate mercury. On a lab scale, phytoremediation of tailings is done with concentrations of 0%, 30%, 50%, and 100%. Planting medium is combined with dried tailings. Pots are used for phytoremediation, and the residence times are 10, 20, and 30 days. With the use of a mercury analyzer, the amount of mercury present in plant media, roots, and shoots is determined. Using the BAC, BCF, and TF values, the mathematical calculation of phytoremediation ability is performed. Hg content ranged from 1.82 to 16.23 ppm in shoots and 5.15 to 37.19 ppm in roots. Throughout the course of treatment, the tailings Hg concentration varied between 13.18 and 220.05 ppm. Plectranthus sp. is categorized as a medium accumulator with a phytoextraction mechanism, according to the analysis’s findings. Hg phytomining is possible with Plectranthus sp., the TF value is 2.38. Within 10 days, Plectranthus sp. most effectively accumulates 50% Hg in tailings.

Contamination of depressional wetlands in the Mpumalanga Lake District of South Africa near a global emission hotspot

The Mpumalanga Lake District (MLD) of South Africa hosts a regionally unique cluster of water bodies of great importance for wetland biodiversity. It is also located close to a global hotspot for coal-fired power station emissions but the local impacts from these sources of pollution are poorly understood. Sediment cores from three contrasting wetlands were 210Pb dated and analysed for a range of contaminants linked to fossil fuel combustion, including trace elements, Hg, sulphur and spheroidal carbonaceous fly-ash particles (SCPs). At the two sites with pre-industrial (1900) baseline sediments, Pb, Zn and especially Cr concentrations and fluxes showed significant increases in the impact period (post-1975). Mercury showed the greatest proportional increase in flux (>4-fold) of all trace metals. Mercury and sulphur concentrations and fluxes showed highly significant correlations with emissions over the corresponding periods, while SCPs in sediments also closely tracked emissions. In a global context, levels of sediment contamination are relatively minor compared with other heavily industrialised regions, with only Cr exceeding the sediment Probable Effects Concentration for biological impact post-1975. Despite the relatively large increases in Hg, concentrations do not reach the Threshold Effects Concentration. The unexpectedly low levels of contamination may be due to i) low levels of many trace contaminants in South African coals compared to global averages, ii) prevailing recirculation patterns which transport pollution away from the study area during the wet season, minimising wet deposition, and iii) pollutant remobilisation through desiccation of wetlands or volatilization. The effects of hydrology and sediment accumulation rates lead to differential transport and preservation of organic-associated and more volatile contaminants (e.g. Hg, S) relative to non-volatile trace elements in wetlands of the MLD. The greatest fluxes of Hg and S are recorded in the site with the highest catchment: lake area ratio, lowest salinity and greatest sediment organic matter content.

Measurement of Heavy Metal Mercury (Hg) Content in The Swamp Eel (Monopterusalbus) as a Bioindicator from Lake Rawa Taliwang

The presence of heavy metals in Lake Rawa Taliwang can originate from various activities in the upstream river, around settlements, and within the lake itself. Mercury (Hg) is a highly toxic heavy metal due to its neurotoxic nature, affecting both organisms and humans. One of the fish found in Lake Rawa Taliwang is the swamp eel. Swamp eels are often caught for consumption and cultured by the local community. This study aims to determine the mercury (Hg) concentration in swamp eels (Monopterus albus) and assess their suitability for consumption. Sampling was conducted using purposive sampling technique at two stations with two replications at each station. Data analysis involved determining mercury concentration in the swamp eel samples using Atomic Absorption Spectroscopy (AAS). The results showed that the mercury concentration in swamp eels from Lake Rawa Taliwang was 0.13 mg/kg. According to the BPOM regulation no. 9 of 2022, the mercury concentration in these swamp eels is still below the permissible limit for metal contamination in food. This indicates that swamp eels were taken from Lake Rawa Taliwang is safe for consumption.

Fish Tissue Mercury in Lakes and the Moderating Effects of Selenium

Fish mercury concentrations result in fish consumption advisories. However, selenium : mercury molar ratios &gt;1 are protective to wildlife and humans. Therefore, we sampled total selenium (TSe) and total mercury (THg) concentrations and molar ratios in sport fish from 50 Idaho (ID) lakes &gt;20 ha and 67 northeastern USA (NE) lakes &gt;1 ha. Sample lakes were selected at random, to obtain unbiased estimates of mean fish tissue levels, with known confidence limits, for target populations of 95 ID lakes &gt;20 ha in surface area and 12,557 NE lakes &gt;1 ha. Bass and salmonids presented the greatest potential mercury toxicity risk to consumers based on their higher mercury content, desirability as game fish, and widespread distributions. Fish tissue THg exceeded safe consumption criteria in an estimated 20–80% of the lakes in the two regions and TSe exceeded safe consumption thresholds in an estimated 0–20% of the lakes in the two regions. However, the Se : Hg molar ratio was &gt;1 in an estimated 90–97% of fish tested from NE and ID lakes. Therefore, we concluded that Se levels in these systems are usually sufficient to limit disruption of selenoprotein activities by Hg, and that fish consumption advisories based on Hg alone are unnecessarily restrictive.

Development and sensitivity analysis of MWCNTs coated D-shaped plastic optical fiber sensor for the detection of mercury

Heavy metal pollutants in rivers and water catchments are one of the problems faced by many developing countries as they may result in health issues among their people. A proper sensing mechanism is required to ensure the quality of water. In this research, we propose a simple, low cost, and highly sensitive D-shaped plastic optical fiber (POF) sensor layered with functionalized multi-walled carbon nanotubes (MWCNTs) for the detection of mercury in water. The sensor underwent interrogation across a range of mercury concentrations at room temperature. Numerous methods of characterization have been employed to explore the intricate structural attributes of the sensing layer to verify that the nanocomposite surface layer is functionalized with minimal disruption to the nanotubes. The experimental results revealed that the coated sensor displayed swift response and recovery time of 6.3 s and 13 s respectively when tested with the dynamic mercury concentration range (0 to 5 ppm). Moreover, it exhibited a relative absorbance of 7.33 %/ppm, which is approximately four times higher than the plain sensor and a limit of detection (LOD) of 0.1 ppm. The sensor has the potential to be transformed into an on-site, portable, real-time optical sensor for the detection of mercury ions in drinking water, offering high sensitivity and fast data acquisition.

A GIS-based analysis of heavy metals around Otukpo rice mill in Benue state

Heavy metals are primarily sourced from natural pedo-geochemical backgrounds and anthropogenic occurrences like composting, sewage sludge, aerosol deposition, and waste animal manure. The study aims to determine the heavy metals within the rice mill in Otukpo to understand the spatial distribution with the objectives to examine the heavy metals within the identified activity areas in the Otukpo rice mill, to determine the spatial distribution of heavy metals within the study area and to compare heavy metal values with the acceptable limits. Soil samples were collected from ten locations at Otukpo Rice Mill to analyze heavy metal concentrations. The samples were collected using sterile bottles and a stainless trowel, and the soil samples were analyzed for the concentrations of Cadmium, Copper, Lead, Nickel, Zinc, Mercury, Iron, Arsenic, and Chromium using the Atomic Absorption Spectrophotometry method. The result was analyzed using interpolation to see the variation of the Heavy metals within the various activity areas. The result of the study reveals that Iron has the highest concentration at the Entrance point and lowest at the Generator house with a range value of 3.92 – 1.12mg/kg respectively. The highest concentration of Zinc was recorded at the Mechanic workshop while the lowest is at the Drying point with a range value of 0.135 – 0.872mg/kg respectively. The Husk dumpsite recorded the highest concentration of Copper (0.666mg/kg) with the Drying point recording the least (0.088 mg/kg). The study reveals uneven concentrations and highlights the effectiveness of the Geographic Information System in mapping heavy metal concentrations.

Adapted Sequential Extraction Protocol to Study Mercury Speciation in Gold Mining Tailings: Implications for Environmental Contamination in the Amazon.

Artisanal small-scale gold mining (ASGM), an increasingly prevalent activity in South America, generates mercury-contaminated tailings that are often disposed of in the environment, leading to the introduction of mercury into ecosystems and the food web, where it bioaccumulates. Therefore, studying the geochemical processes involved in the desorption and dissolution of mercury in these tailings is essential for critical risk evaluations in the short and long term. For this purpose, sequential extraction procedures (SEPs) can be useful because they help to identify the phases to which Hg is associated, although they also have limitations such as a lack of selectivity and specificity. In this work, we propose a modified four-step SEP: exchangeable mercury (F1), oxidizable mercury (F2), mercury bound to Fe oxides (F3), and strongly bound mercury (F4). To test this adapted sequential extraction method, we evaluated the Hg contamination in mercury-contaminated tailings of the Amazon basin. The results revealed a total mercury concentration of 103 ± 16 mg·kg-1 in the tailings, with a significant portion in F1 (28% of the total), where Hg was bioavailable. The large Hg concentration in F3 (36%) suggested that Fe oxides likely contribute to mercury retention. Together, the SEP results emphasize the urgent need for improved surveillance of gold mining activities and responsible tailings management practices to mitigate environmental contamination and safeguard the health of the Amazon ecosystem.

Impacts of Spectral Characteristics of Dissolved Organic Matter on Methyl Mercury Contents in Permafrost Wetlands, Northeast China

Impacts of Spectral Characteristics of Dissolved Organic Matter on Methyl Mercury Contents in Permafrost Wetlands, Northeast China

Mercury exposure in the Norwegian Mother, Father, and Child Cohort Study – measured and predicted blood concentrations and associations with birth weight

BackgroundBlood total mercury concentration (BTHg) predominantly contains methyl Hg from seafood, and less inorganic Hg. Measured BTHg is often available only in a small proportion of large cohort study samples. Associations between estimated dietary intake of total Hg (THg) and lower birth weight within strata of maternal seafood intake was previously reported in the Norwegian Mother, Father, and Child Cohort Study (MoBa). However, maternal seafood consumption was associated with increased birth weight, indicating negative confounding by seafood in the association between THg intake and birth weight. Using predicted BTHg as a proxy for measured BTHg, we hypothesized that predicted BTHg would be associated with decreased birth weight. ObjectivesTo develop and validate a prediction model for BTHg in MoBa and to examine the association between predicted BTHg and birth weight in the MoBa population. MethodsUsing linear regression, measured maternal BTHg (n = 1437) was used to build the best fitting model (highest R-squared value). Model validation (n = 1436) was based on correlation and weighted Kappa (Кw). Associations between predicted BTHg in the MoBa population (n = 86,775) or measured BTHg (n = 3590) and birth weight were assessed by multivariate linear regression models. ResultsThe best fitting model had R-squared = 0.3 and showed strong correlation (r = 0.53, p < 0.001) between predicted and measured BTHg. Cross-classification (quintiles) showed 73 % correctly classified and 3.3 % grossly misclassified, with Кw of 0.37. Measured BTHg was not associated with birth weight. Predicted BTHg was significantly associated with higher birth weight. There were no trends in birth weight with increasing quintiles of measured or predicted BTHg after stratification into high or low seafood consumption. ConclusionsThe results indicate that prediction of BTHg did not overcome negative confounding of the association between Hg exposure and birth weight by seafood intake. Furthermore, effect on birth weight of toxicological concern is unexpected in our observed BTHg range.

Detection of Mercury in Skin Lightening Cosmetics Marketed in Katsina Metropolis, Katsina State, Nigeria

Deliberate use of metals as active cosmetic ingredients has been banned in many countries due to their persistent nature, toxicity and transdermal exposure over a certain period of time. Fifteen (15) samples were purposively sampled to cover the most frequently used brands as the samples for the study. The samples cover five (5) of each of the skin lightening creams, lotions and soaps from different cosmetics shops in Katsina central market and other outlets within the metropolis of Katsina. Qualitative inorganic analysis was conducted for the detection of the presence of mercury in the samples. Also quantitative analysis of the mercury was carried out using Atomic Absorption Spectrometry (AAS). The results for the qualitative inorganic analysis showed that all the samples were mercury (II) positive with 0.5N KI reagent through the formation of reddish orange precipitate, and no positive reaction of mercury was detected using 2.0N NaOH reagent. Quantitative analysis of the mercury revealed the presence of mercury in all the analyzed samples. The concentration of mercury ranged from 27.7 ± 0.0006 to 61.5 ±0. 0007 ppm. From the results obtained, it is thus evident that the analyzed samples were mercury (II) positive and above the recommended WHO permissible limit. Therefore, there may be a serious health hazard to the users of such products in Katsina metropolis. It is recommended that periodic analysis of such skin lightening products should be conducted by the regulatory bodies to ascertain their safety to the users.