Total mercury concentrations in human hair from 13 countries in relation to fish consumption and location

Five hundred and fifty nine samples of human head hair from 32 locations in 13 countries were analysed for mercury. Tests of different techniques for cleaning and storing samples showed that at ambient air mecury concentrations contamination of samples is undetectable. Arithmetic mean mercury concentrations for people who ate fish 1–4 times each month were: Australia, 2.5 ppm; Canada, 1.2 ppm; China, 0.9 ppm; West Germany, 0.5 ppm; Hong Kong, 3.0 ppm; Italy, 1.5 ppm; Japan, 3.9 ppm; Monaco, 1.7 ppm; New Zealand, 1.3 ppm; Papua New Guinea, 1.8 ppm; South Africa, 1.9 ppm; U.K., 1.6 ppm and USA, 2.4 ppm. The differences are believed to be due to diet and environment. Mean hair mercury concentrations were significantly different for the group that ate fish once or less a mont (1.4 ppm) once a fortnight (1.9 ppm) once a week (2.5 ppm) and once or more a day (11.6 ppm). Simplified models of mercury pathways in the environment and man are presented. Hair mercury concentrations measured here and those reported in the literature suggested that the weighted mean hair mercury concentration of people living in both northern and southern hemispheres at latitudes 40° had hair mercury concentrations which were significantly lower than at other latitudes, even in industrialized countries. It is suggested that lower soil temperatures could retard mercury volatilization and inhibits its movement into pathways which get back to man.     

The tropical African mercury anomaly: lower than expected mercury concentrations in fish and human hair

Mercury is a neurotoxin and global pollutant, and wetlands and newly flooded areas are known to be sites of enhanced production of monomethylmercury, the form of mercury that is readily biomagnified in aquatic food chains to potentially toxic levels. The Okavango Delta in Botswana, Southern Africa, is the largest inland delta in the world and a wetland ecosystem that experiences dramatic annual flooding of large tracts of seasonal floodplains. The Delta was, therefore, expected to be home to high mercury levels in fish and to be an area where local subsistence fishing communities would be at substantial risk of mercury toxicity from fish consumption. Total mercury concentrations measured in 27 species of fish from the Okavango Delta averaged (mean ± s.d., wet weight) 19 ± 19 ng g⁻¹ in non-piscivorous fish, and 59 ± 53 ng g⁻¹ in piscivorous fish. These mercury concentrations are similar to those reported for fish from lakes in other areas of tropical Africa, demonstrating that not all wetlands are sites of elevated mercury concentrations in biota. Even more intriguing is that concentrations of mercury in fish from across tropical Africa are systematically and substantially lower than those typically reported for fish from freshwater ecosystems elsewhere globally. The reasons for this apparent “African mercury anomaly” are unclear, but this finding poses a unique opportunity to improve our understanding of mercury's biogeochemical cycling in the environment. Mercury concentrations measured in human hair collected in subsistence fishing communities in the Okavango Delta were similarly low (0.21 ± 0.22 μg g⁻¹ dry weight) despite high levels of fish consumption, and reflect the low mercury concentrations in the fish here.     

Total mercury levels in whole blood, hair and fingernails for a population group from Rome and its surroundings.

Whole blood, hair and fingernails of 80 representative subjects from the Province of Rome were analysed for total mercury. The mean value for whole blood was 0.020 mg/kg, for hair 0.51 mg/kg and for nails 1.08 mg/kg. Correlations were found (except for hair) between mercury levels and the number of fish meals, mercury amalgam dental fillings and residence (urban or rural) of the subjects examined. The levels found in hair appear to be influenced by external and individual pollution factors and thus unsuitable for any direct determination of the distribution in other organs of the human body.     

Total mercury,methylmercury and selenium in mercury polluted areas in the province Guizhou,China

The province of Guizhou in Southwestern China is currently one of the world's most important mercury production areas. Emissions of mercury from the province to the global atmosphere have been estimated to be approximately 12% of the world total anthropogenic emissions. The main objective of this study was to assess the level of contamination with Hg in two geographical areas of Guizhou province. Mercury pollution in the areas concerned originates from mercury mining and ore processing in the area of Wanshan, while in the area of Quingzhen mercury pollution originates from the chemical industry discharging Hg through wastewaters and emissions to the atmosphere due to coal burning for electricity production. The results of this study confirmed high contamination with Hg in soil, sediments and rice in the Hg mining area in Wanshan. High levels of Hg in soil and rice were also found in the vicinity of the chemical plant in Quingzhen. The concentrations of Hg decreased with distance from the main sources of pollution considerably. The general conclusion is that Hg contamination in Wanshan is geographically more widespread, due to deposition and scavenging of Hg from contaminated air and deposition on land. In Quingzhen Hg contamination of soil is very high close to the chemical plant but the levels reach background concentrations at a distance of several km. Even though the major source of Hg in both areas is inorganic Hg, it was observed that active transformation of inorganic Hg to organic Hg species (MeHg) takes place in water, sediments and soils. The concentration of Hg in rice grains can reach up to 569 microg/kg of total Hg of which 145 microg/kg was in MeHg form. The percentage of Hg as MeHg varied from 5 to 83%. The concentrations of selenium can reach up to 16 mg/kg in soil and up to 1 mg/g in rice. A correlation exists between the concentration of Se in soil and rice, indicating that a portion of Se is bioavailable to plants. No correlation between Hg and Se in rice was found. Exposure of the local population to Hg may occur due to inhalation of Hg present in air (in particular in Hg mining area) and consumption of Hg contaminated food (in particular rice and fish) and water. Comparison of intake through these different routes showed that the values of Hg considerably exceed the USA EPA Reference Concentration (RfC) for chronic Hg exposure (RfC is 0.0004 mg/m(3)) close to the emission sources. Intake of Hg through food consumption, particularly rice and fish, is also an important route of Hg exposure in study area. In general, it can be concluded that the population mostly at risk is located in the vicinity of smelting facilities, mining activities and close to the waste disposal sites in the wider area of Wanshan. In order to assess the real level of contamination in the local population, it is recommended that biomonitoring should be performed, including Hg and MeHg measurements in hair, blood and urine samples.     

Total mercury and methyl mercury levels in British estuarine and marine sediments

Total mercury and methyl mercury levels in some British estuarine and marine sediments are presented. Results are compared for estuaries of the Rivers Clyde and Mersey. These, together with data from Irish Sea sediments, are discussed in comparison with other literature values. The use of the methyl mercury to total mercury ratio is examined.     

Monitoring of mercury pollution in Tanzania: relation between head hair mercury and health

Through 1996 into 1997, a spot investigation on mercury contamination was conducted three times in Tanzania, especially around the Lake Victoria. A total of 150 goldminers, 103 fishermen and their families, and 19 residents of Mwanza City volunteered for the current study. A high total mercury level of 48.3 ppm (near to 50 ppm, a critical level of Minamata disease) and over in the head hair was observed in six goldminers (highest value, 953 ppm), four fishermen and their families (highest value, 416 ppm), and four Mwanza people (highest value, 474 ppm). With the exception of these 14 subjects, however, each mean total mercury level was well within the normal range (below 10 ppm). Out of the goldminers examined, 14 cases were diagnosed as a mild form of inorganic-mercury poisoning according to their clinical symptoms (such as polyneuropathy mercurialis, neuroasthemia, or tremor mercurialis) and the low ratio of methylmercury to total mercury, whereas neither inorganic-mercury poisoning nor methylmercury poisoning (Minamata disease) was noted in the fishermen and their families or in the Mwanza people. In addition, some subjects who showed a high total mercury level made habitual use of toilet soap containing much mercury. The findings obtained suggest that the mercury pollution in Tanzania is not very serious, however, it should be observed continuously.     

Total mercury and methyl mercury levels in British estuarine sediments—II

Results from a large-scale study of Mersey Estuary, U.K. sediments are discussed. Correlations are drawn between total mercury, methyl mercury, silt and organic carbon contents of the sediments. These correlations are compared to earlier results, and coefficients range from 0.55 to 0.94.The influence of redox potential and the sulphide content of a sediment on both the ambient level of methyl mercury and the extent of a growth and decay effect in methyl mercury levels in sediments after sampling is discussed. The results show that in an esturary (Clyde, U.K.) where sulphide levels vary from 0 to 8.5 mg g⁻¹ there is a maximum level of methyl mercury found at approximately 5.8 mg g⁻¹ sulphide, suggesting that sulphide concentrations may control methyl mercury levels.     

Total gaseous mercury in the atmosphere of Guiyang,PR China

Four measurement campaigns were carried out to monitor total gaseous mercury (TGM) at one site in the Guiyang City, PR China in the following periods: April 19-30, 2000; February 26-March 14, 2001; June 26-July 20, 2001; and October 9-November 22, 2001, respectively. High temporal resolved data were obtained by using automated mercury analyzers Gardis 1A and Tekran 2537A. TGM data from all measurement periods followed the typical log normal distribution pattern. The geometric mean of TGM from different seasons were 8.56, 7.45, 5.20 and 8.33 ngm(-3) in spring 2000, winter 2001, summer 2001 and autumn 2001, respectively. The overall average TGM covering the sampling periods was 7.39 ngm(-3), which is significantly elevated comparing to global background of approximately 1.5-2.0 ngm(-3). The major anthropogenic atmospheric mercury emission sources differed significantly among seasons, which caused the seasonal variability of TGM level. Distinct daily variability of TGM was observed among seasons. The daytime TGM concentrations were larger than that of nighttime in spring and winter seasons, while in summer and autumn the opposite daily TGM distribution pattern was observed.     

Concentrations of some trace elements in hair, liver and kidney from autopsy subjects--relationship between hair and internal organs

Autopsy samples of hair, liver and kidney cortex from 30 Swedish subjects (Caucasian) were analysed for Ag, Co, Cr, Hg, Sb, Se and Zn by neutron activation analysis (NAA). The following elements were observed to have higher concentrations in hair than in liver and kidney cortex: Ag, (Co), Cr and Hg (on a dry weight basis). Selenium was highly concentrated in kidney cortex, and Fe in liver. The observed concentrations of most of the elements were very variable for each tissue. In particular, Co values for hair showed more than a 5000-fold difference. However, Se values for hair were relatively constant. A highly significant positive correlation was observed between Hg concentrations in hair and kidney cortex. Somewhat weaker correlations were found between Hg in kidney cortex and liver and Se in hair and kidney cortex. The concentration of Co in liver correlated with that in kidney cortex. It was concluded that, with the exception of mercury, and to a lesser degree selenium, hair analysis did not provide a useful measure of the trace element status of the subjects included in this study.     

Platinum in the human diet, blood, hair and excreta.

Baseline levels of platinum in the blood, hair and urine of 21 adults from Sydney, Australia, and three adults from the relatively unpolluted area of Lord Howe Island, Australia, were determined by adsorptive voltammetry. The median concentrations of platinum in samples from residents in Sydney were: whole blood, 0.56 microgram Pt l-1; hair, 3.84 micrograms Pt kg-1; urine, 0.18 microgram Pt l-1 (0.23 microgram Pt g creatinine). Samples from residents of Lord Howe Island had platinum levels that were within the range of values of the corresponding samples from Sydney residents. For faeces samples, the median platinum concentration was 10.5 micrograms kg-1 FW. The excretion of platinum over a 4-day period was measured in one adult male. Urinary excretion of platinum was between 0.76 and 1.07 micrograms Pt day-1 and in faeces it was between 0.61 and 0.73 microgram Pt day-1. The concentrations of platinum in a range of foodstuffs from Sydney were between 8.11 micrograms kg-1 FW for liver and 0.13 microgram kg-1 FW for full-cream milk. This information as well as the amounts of these foods in hypothetical diets for Australians was used to calculate the total dietary intake of platinum. The average diet of a Sydney adult contains 1.44 micrograms of platinum per day (adult male, 1.73 micrograms Pt day-1; adult female, 1.15 micrograms Pt day-1). The uptake of dietary platinum from the gut was estimated to be at least 42% and, therefore, diet appears to make a substantial contribution to total platinum intake.     

Burdens of mercury in residents of Temirtau, Kazakhstan: I: Hair mercury concentrations and factors of elevated hair mercury levels

Mercury (Hg) is released either naturally in the environment or by anthropogenic activities. During its global circulation, Hg presents in a diversity of chemical forms and transforms between each other. Among Hg species, methylmercury (MeHg) is readily absorbed by humans via the aquatic food chain and thus it is very neurotoxic to exposed populations including fetuses due to perinatal exposure. In 2005, a survey was carried out in Temirtau, an Hg-contaminated site in North Central Kazakhstan, to investigate Hg concentrations in the hair samples of the residents and the relationship between Hg exposure levels and the related factors. Among the 289 hair samples, Hg concentrations ranged from 0.009 to 5.184 µg/g with a mean of 0.577 µg/g. Nearly 17% of the population exceeded 1 µg/g for hair Hg, which corresponds to the reference of dose (RfD) 0.1 µg/kg body weight/day developed by the United States Environmental Protection Agency (USEPA). Subgroups of males, people aged over 45 and fishermen or anglers were found to have elevated Hg exposure levels in their hair. A positive correlation was found between Hg concentrations in hair and frequencies of river fish consumption. As a result, the finding that people were exposed to high levels of Hg was expected due to the frequent consumption of fish caught from the polluted River Nura or the neighbouring lakes. A regression model showed that approximately 41% of variance of Hg concentrations in the study population's hair was attributed to the variables of gender, residential location, age and fishery occupation. The model implied that demographic characteristics together with dietary behaviour should be taken into account in studies associated with Hg exposure risk, in order to clearly define the group potentially sensitive to Hg exposure.     

A note on mercury levels in the hair of Alaskan reindeer

Reindeer, as terrestrial herbivores, generally have low levels of Hg, but monitoring Hg levels can help in understanding ecological toxicity related to a changing environment. In this study, Alaskan reindeer were analyzed for total mercury (THg) in their hair. Both free-ranging reindeer from the Seward Peninsula, Alaska and reindeer fed a pollock-based fishmeal diet were surveyed. Free ranging reindeer had mean THg levels of (55.3 ng/g; n=5). The mean MeHg level in the free ranging reindeer was 45.5 (ng/g; n=5) or 79% of the THg level. The mean level for THg in the fishmeal fed reindeer was 19 ng/g (n=10). Younger reindeer (2 years of age or less) showed lower levels (0.8 ng/g, n=2) compared to adult reindeer (30.8 ng/g, n=6).     

Total mercury distribution in sediment cores from Kuwait Bay

Five sediment cores from Kuwait Bay were taken in order to study the present distribution of total mercury (THg) in the vicinity of the Salt and Chlorine Plant (SCP) operated in the 1963–1985 period. The THg concentration profiles were also determined in four sediment cores from the northern part of Kuwait Bay. Additionally, average THg contents were measured in the surface layer (40 cm) of five sediment samples in the entrance of Kuwait Bay, in order to compare the present Hg levels in other parts of this reservoir. The cores were dated by ²¹⁰Pb method. The observed contents of mercury were in the range of 35 to 2000 µg/kg dry weight (ppb). Thus, the bottom sediments in these three areas of Kuwait Bay are still contaminated by Hg. In a few cases, the depth concentration profiles of THg were disturbed as an effect of partial mixing of the sediment layers, especially in the shallow, northern part of Kuwait Bay. This suggestion was supported by the results of additional measurements of the anthropogenic ¹³⁷Cs profiles in the same cores.     

Selenium and its interrelatiosn with mercury in wholeblood and hair in an East Greenlandic population

138 Blood samples and 12 hair samples from the district of Angmagssalik, East Greenland, have been analysed for selenium and mercury. It was found that selenium like mercury, was absorbed in accordance with the amount of marine food eaten. The mean blood concentration in the group eating most marine food was 173 and 186 μg Hg/1 for men and women, respectively, while in the group eating the lowest quantity of marine food, the mean values were 86 and 118 μg Hg/1. In blood, the selenium and mercury did not correlate in individuals, but only in groups according to eating habits. On a molar basis, selenium is present in blood in excess as compared to mercury, while the opposite is the case for hair. It is concluded that only part of the selenium interacts with mercury, and that blood, but not hair, reflects present dietary intake. The rich supply of selenium in relation to mercury exposure through the traditional arctic food is probably able to alleviate the hazards from dietary mercury exposure.     

Total gaseous mercury in Quebec (Canada) in 1998

The main objectives of this paper were to report total gaseous mercury (TGM) concentrations at four stations along the St. Lawrence River in 1998 and to give some insights regarding their fate. The TGM network stretches from latitudes 45 degrees N to 50 degrees N. TGM and ozone concentrations (used as complementary pollutant) were presented. The median TGM concentrations throughout the network varied from 1.62 to 1.79 ng/m3. Sites close to Montreal had larger TGM concentrations. Montreal surroundings appeared to be a source of TGM. The TGM concentrations were maximum in wintertime and minimum in summertime throughout the sites. However, the diurnal variations were site specific. St. Anicet and L'Assomption were more variable in terms of large concentrations, whereas Mingan and Villeroy were more variable in terms of low concentrations. Ozone and TGM concentrations were positively correlated at some sites (Villeroy, Mingan and St. Anicet) whereas they were not at L'Assomption (closest site to Montreal). Local TGM and ozone precursor sources would affect the correlation.     

Total mercury and methylmercury levels in fish from hydroelectric reservoirs in Tanzania

Total mercury (THg) and methylmercury (MeHg) levels have been determined in fish species representing various tropic levels in four major hydroelectric reservoirs (Mtera, Kidatu, Hale-Pangani, Nyumba ya Mungu) located in two distinct geographical areas in Tanzania. The Mtera and Kidatu reservoirs are located along the Great Ruaha River drainage basin in the southern central part of the country while the other reservoirs are located within the Pangani River basin in the north eastern part of Tanzania. Fish mercury levels ranged from 5 to 143 microg/kg (mean 40 microg/kg wet weight) in the Mtera Reservoir, and from 7 to 119 microg/kg (mean 21 microg/kg) in the Kidatu Reservoir downstream of the Great Ruaha River. The lowest THg levels, in the range 1-10 microg/kg (mean 5 microg/kg), were found in fish from the Nyumba ya Mungu (NyM) Reservoir, which is one of the oldest reservoirs in the country. Fish mercury levels in the Pangani and Hale mini-reservoirs, downstream of the NyM Reservoir, were in the order of 3-263 microg/kg, with an average level of 21 microg/kg. These THg levels are among the lowest to be reported in freshwater fish from hydroelectric reservoirs. Approximately 56-100% of the total mercury in the fish was methylmercury. Herbivorous fish species contained lower THg levels than the piscivorous species; this was consistent with similar findings in other fish studies. In general the fish from the Tanzanian reservoirs contained very low mercury concentrations, and differed markedly from fish in hydroelectric reservoirs of similar age in temperate and other regions, which are reported to contain elevated mercury concentrations. The low levels of mercury in the fish correlated with low background concentrations of THg in sediment and flooded soil (mean 2-8 microg/kg dry weight) in the reservoir surroundings. This suggested a relatively clean reservoir environment that has not been significantly impacted by mercury contamination from natural or anthropogenic sources.     

Sequential analysis of hair mercury levels in relation to fish diet of an Amazonian population, Brazil

Several studies in the Amazonian Basin have shown that riverine populations are exposed to methylmercury through fish consumption. It has been suggested that seasonal variations in hair mercury observed through sequential analyses may be related to the changes in fish species ingested by the local communities. The aim of the present study was to investigate the relationship between fish-eating practices and seasonal variation in mercury exposure. A group of 36 women from a village located on the banks of the Tapajós River, a major tributary of the Amazon, comprised the present study population. An interview-administered questionnaire was used to gather information on socio-demographic characteristics, fish-eating practices and other relevant information. The women also provided hair samples of at least 24 cm in length for mercury analysis. Hair total and inorganic mercury concentration was measured using a cold vapor atomic absorption analytical method. Trigonometric regression analysis was done to assess the seasonal variation of total mercury levels. Variations in inorganic mercury were examined by repeated measures analysis of variance, and analysis of contrast variable with a polynomial transformation. The results showed that hair mercury levels varied with the season. Higher levels were observed in months corresponding to the dry season, with lower levels in the rainy season. Herbivorous fish predominated the diet for 47.2% of the women during the dry season, but this rose to 72.2% during the rainy season. Those who reported eating fish daily had higher mercury levels in hair compared to those who only ate fish a few times per week. Retrospective mercury analyses, evaluated by the quantity of mercury present in each centimeter of hair, indicate that mean mercury level of the population decreased over the 2 years prior to the study. The percentage of inorganic mercury over the total mercury in hair increased towards the extremities of the hair strand. Higher percentages of inorganic mercury were found for the group who ate more fish (on a daily consumption basis). These results support the assumption that there are seasonal variations in methylmercury exposure and also a relationship between type of fish species consumed and the resulting hair mercury levels.     

The mercury content of hair of Japanese immigrants in various locations in South America

Hair mercury levels in four Japanese immigrant settlements in South America were determined by cold-vapor atomic absorption spectrometry. The levels in the two Bolivian settlements were relatively higher (6.22 and 3.53 ppm for males, 3.66 and 2.23 ppm for females) than those in Brazil (2.19 ppm for males, 1.57 ppm for females) and in Paraguay (2.40 ppm for males, 2.04 ppm for females). The levels in Bolivia were almost the same as recent Japanese levels. Dose-response relationships between frequency of eating fish and hair mercury level were found in all the settlements. However, even in the same fish-eating category, the content varied from place to place. Significant correlations between husbands and wives were demonstrated in three out of four settlements. These results imply that the mercury content of hair is regulated by the life style within each family. That is, inhabitants of Japanese settlements, especially in Bolivia, maintain their Japanese habit of fish eating. This results in a high hair mercury content, even when they live in a rural area and consume only fish from the head rivers of the Amazon.     

Total mercury and methylmercury in high altitude surface snow from the French Alps

Surface snow samples were collected weekly from the 31st of December 2008 to the 21st of June 2009 from Lake Bramant in the French Alps. Total mercury (THg), total dissolved mercury (THgD), methylmercury (MeHg) and particle distributions in surface snow were analyzed. Results showed that THg concentrations, MeHg concentrations and particle load increased with snow surface temperature, which is an indicator of rising temperatures as the season progresses. Significant correlations between MeHg and snow surface temperature and MeHg and total particles greater than 10 μm were observed. This suggests that the MeHg found in the snow originates from atmospheric deposition processes rather than in situ snowpack sources. This study suggests that an important post-winter atmospheric deposition of MeHg and THg occurs on summital zones of the French Alps and it is likely that this contamination originates from the surrounding valleys.     

Total mercury in Pema perna mussels from Guanabara Bay--10 years later

Guanabara Bay (GB) is an important estuary in regard to the productivity of the southeastern Brazilian coast. It is heavily polluted by oil, land runoff, and sewage, had large areas reclaimed, and its basin has been seriously deforested. The objective of the present work is to compare the total mercury levels in mussels from the bay, measured at the beginning and at the end of a 10-year interval (1988 and 1998). The commonly occurring species of bivalve in the bay is the mussel Perna perna. The total mercury content in mussels from GB has probably remained constant for the last 10 years (17.3-74.1 microg Hg kg(-1)), with possible isolated fluctuations attributed to occasional changes in water quality. Mussels have a good potential as biomonitors of water quality in GB. The need for the establishment of long-term biomonitoring programs is also commented.