Mercury in human hair: a study of residents in Madrid, Spain

Effects of sex on the levels of metals and metalloids in the hair of a group of healthy Spanish adolescents (13 to 16 years old)

Human biomonitoring can be a reliable tool to protect the health of the citizens of major urban environments. Human hair may be an invaluable specimen to determine chronic exposure to any environmental contaminant in an individual, especially in the young population. However, different factors including a lack of studies that have established reference values for metals and metalloids (trace elements) in human scalp hair make the use of this matrix controversial. A monitoring study was performed to establish possible normal or tentative reference values of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Pb, Sn, Ti, Tl and Zn in adolescents' (aged 13-16) hair who have lived since birth in Alcalá de Henares, Madrid region (Spain). Strict inclusion criteria were followed to study the effect of sex on the hair metal content, and the levels of the above contaminants were also studied in park topsoils from Alcalá de Henares. Scalp hair samples were collected from 96 healthy adolescents (28 boys and 68 girls), and reference values were calculated following the recommendations of the International Union of Pure and Applied Chemistry. The levels of Cd, Cu, Pb, Sn and Zn in hair of adolescents from Alcalá de Henares show a sex dependency, being significantly higher in female participants. Sex should be a factor taken into account when developing future reference values and hair metal content. Soil metal contamination was not correlated with the levels found in hair. To conclude, the values of metals and metalloids here analysed and discussed could be considered as tentative reference values for Spanish adolescents aged 13-16 years living in the Madrid region, and may be used to identify the level of exposure of adolescents in this Spanish region to the various metals and metalloids.

"Reference values" of trace elements in the hair of a sample group of Spanish children (aged 6-9 years) - are urban topsoils a source of contamination?

Human hair is used as a biomonitor to evaluate the environmental exposure to contaminants in the individual. However, the use of human hair is controversial, mainly because reference levels for pollutants in hair have not yet been set. In the case of Spain, few biomonitoring studies have involved infants and children. A biomonitoring study was conducted to investigate the possible normal values of trace elements of toxicological concern in children aged 6-9 years from the city of Alcalá de Henares, Community of Madrid (Spain), following the methodology and strict inclusion criteria previously developed by our group. Levels of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Ti, Tl, V and Zn were monitored in scalp-hair from 117 healthy children (47 boys and 70 girls) between April and May of 2001. The levels of trace elements here described could be considered as possible "reference values" for children aged 6-9 years resident in the Community of Madrid. These values might also be selected as a preliminary screening tool to evaluate if a Spanish child has been exposed to any of the contaminants studied here. This study also investigated whether local urban topsoils were a source of metals for this population.

Hair mercury and urinary cadmium levels in Belgian children and their mothers within the framework of the COPHES/DEMOCOPHES projects

A harmonized human biomonitoring pilot study was set up within the frame of the European projects DEMOCOPHES and COPHES. In 17 European countries, biomarkers of some environmental pollutants, including urinary cadmium and hair mercury, were measured in children and their mothers in order to obtain European-wide comparison values on these chemicals. The Belgian participant population consisted in 129 school children (6-11 years) and their mothers (≤ 45 years) living in urban or rural areas of Belgium. The geometric mean levels for mercury in hair were 0.383 μg/g and 0.204 μg/g for respectively mothers and children. Cadmium in mother's and children's urine was detected at a geometric mean concentration of respectively 0.21 and 0.04 μg/l. For both biomarkers, levels measured in the mothers and their child were correlated. While the urinary cadmium levels increased with age, no trend was found for hair mercury content, except the fact that mothers hold higher levels than children. The hair mercury content increased significantly with the number of dental amalgam fillings, explaining partially the higher levels in the mothers by their higher presence rate of these amalgams compared to children. Fish or seafood consumption was the other main parameter determining the mercury levels in hair. No relationship was found between smoking status and cadmium or mercury levels, but the studied population included very few smokers. Urinary cadmium levels were higher in both mothers and children living in urban areas, while for mercury this difference was only significant for children. Our small population showed urinary cadmium and hair mercury levels lower than the health based guidelines suggested by the WHO or the JECFA (Joint FAO/WHO Expert Committee on Food Additives). Only 1% had cadmium level slightly higher than the German HBM-I value (1 μg/l for adults), and 9% exceeded the 1 μg mercury/g hair suggested by the US EPA.

Metals (Hg, Pb, Cu, and Zn) bioaccumulation in sediment, fish, and human scalp hair: a case study from the city of mersin along the southern coast of Turkey

This study investigates mercury, lead, copper, and zinc concentrations in six most frequently consumed fish species (120 samples), sediments (20 samples) taken from Karaduvar Fishing Area where fish species live, and Mersin Port as a contrary region, and human scalp hair for people regularly consuming these fish species (50 samples) and non-fish-eaters (15 samples) in Mersin, Turkey. On taking living environment into account, the fish groups include pelagic species of Liza saliens, Liza aurata, and demersal species of Merluccius merluccius, Mullus barbatus, Upeneus moluccensis, and Solea solea. Total Hg (THg) was found to accumulate in muscle tissues at the lowest concentration (0.01 microg/g) in L. saliens and at the highest (2.66 microg/g) in S. solea. Pb was only detected at high concentrations of 1.86 microg/g in M. barbatus and of 2.16 microg/g in M. merluccius. Cu and Zn concentrations were below the detection limit within all fish species. In the sediment samples, Pb and Cu concentrations were persistently below their effect range-median (ERM) value, whereas this limiting value only maintained for 15% of THg concentrations. On the other hand, the effect range-low (ERL) of sediment exceeded at Pb in 15% of samples and Cu in 25% of samples. Zn remained below the detection limit for sediment samples. The metal concentrations at scalp hairs of regular consumers of these fish groups and non-fish eaters vary from the range 0.40-3.28 to 0.14-1.02 microg/g for THg, 11.16-107.84 to 8.00-22.38 microg/g for Pb, and 151.67-645.35 to 144.92-343.50 microg/g for Zn. An important finding of the present study is the significant adverse impact of sedimentary heavy metal bioaccumulation to human through the consumption of demersal fishes in the city of Mersin along the southern coast of Turkey.

Changes in children hair-Hg concentrations during the first 5 years: Maternal, environmental and iatrogenic modifying factors

Children are exposed to Hg from mothers (via placenta and lactation), environment (food), and in many parts of the world by thimerosal-containing vaccines (TCV) during immunization. Neurodevelopment studies based on infant hair-Hg (HHg) have been designed without explicit attention to the factors associated with changes in infant physiology and Hg sources of exposure. A longitudinal study of changes in HHg concentrations from birth to 5 years was done in a sample of children from Porto Velho (Rondonia), Brazilian Amazonia. The study extracted information from the asymmetry associated with maternal and infant HHg changes at specified sampling: birth (fetal exposure), 6 months of exclusive breastfeeding, 36 months (weaning) and 60 months (pre-school). The distribution of HHg in breastfed infants followed a pattern different from their mothers. While mothers had the highest HHg concentrations at childbirth, infants showed the highest HHg values at 6 months after the recommended full schedule (six shots) of immunization with TCV; after that, the downward trend in HHg shown by children coincided with both weaning and less frequent vaccination period (5 years). Extended lactation (up to 36 months) was not significantly associated with HHg of infants or mothers; however, significant association (Spearman's r) between maternal and infant HHg concentration was seen at birth (r=0.3534; P=0.001), 6 months (r=0.4793; P<0.0001), 3 years (r=0.0122; P=0.012) and 5 years (r=0.0357; P=0.005). Maternal postpartum metabolic changes, infant development and transitional diets and possibly Hg from TCV contribute to the asymmetry of HHg changes between mothers and children.

Mercury in human hair and relation to fish consumption in Bangladesh

Human scalp hair mercury concentrations were determined in 219 hair samples from male individuals from different regions of Bangladesh. Total hair mercury concentrations were very low with a mean value of 0.44 +/- 0.19 micrograms Hg/g (range 0.02-0.95) for a moderately elevated fish consumption averaging 2.1 kg/month (range 1.4-2.6). A highly significant positive correlation (r = 0.88, P < 0.001) was found between fish consumption and hair mercury concentration. Neither age, region nor occupation had any influence on the hair mercury content. Our results in agreement with literature values, are described by equation (X = 183Y + 0.16) linking calculated daily methylmercury intake (X, mg) and hair total mercury level (Y, micrograms/g). Low concentrations in hair were linked to extremely low levels of daily mercury intake, the determining factor being remarkably low mercury levels in Bangladesh fish.

Ofloxacin in human hair determined by high performance liquid chromatography

A procedure is presented for quantitating ofloxacin (OFLX) in human scalp hair by high performance liquid chromatography (HPLC) with a fluorescence detector. An octadecylsilane (ODS) column was used and the mobile phase was a mixture of potassium phosphate buffer (pH 2.6) and acetonitrile. The recovery of OFLX was 90.9-93.8% and within- and between-run precisions were 0.35-1.41% and 1.41-5.49% as the coefficient of variation (CV), respectively, when 5-50 ng OFLX was added to 1 mg blank hair. The calibration curve was linear in the range of 0.5-50 ng/tube (0.5 ml). Interference with other quinolone derivatives could be avoided according to the difference in their retention times or fluorescence spectra. Several pieces of hair were obtained from each of twelve healthy male volunteers, who had taken OFLX (100, 300 or 900 mg total dose) over a 1-3 day period 2 weeks before the hair sampling. In all hair samples except one obtained from a volunteer, who had taken the lowest dose, the 2-cm long segments nearest the scalp contained OFLX (5-45 ng/mg hair), while the upper segments did not. A highly significant positive correlation was observed between the total dose and the concentration of OFLX in the 2-cm long hair segments. Such a positive correlation was also revealed in rat hair sampled after repeated i.p. administration of OFLX over a 5-week period. These results suggest that the measurement of OFLX in hair by the present method would be useful for testing patient compliance in clinical pharmacology as well as for application to forensic science.