Zdravko Špirić

Mosses as biomonitors of atmospheric heavy metal deposition: Spatial patterns and temporal trends in Europe

In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found.

Mercury, arsenic and selenium exposure levels in relation to fish consumption in the Mediterranean area

In order to assess mercury (Hg), selenium (Se) and arsenic (As) exposure in the Mediterranean area, total mercury (THg), monomethylmercury (MeHg), Se and As levels were measured in umbilical cord blood and breast milk from Italian (n=900), Slovenian (n=584), Croatian (n=234) and Greek (n=484) women. THg, MeHg, As, and Se levels were also determined in blood samples of the same mothers from Italy and Croatia. In addition, THg and MeHg were determined in the same womens hair from all the countries involved in this study and As and Se levels were determined in the mothers urine samples from Italy, Croatia and Greece. Besides recording the consumption of other food items, the frequencies of fish consumption were assessed by detailed food frequency questionnaires, since fish represents an important source of Hg, Se and As in humans. The highest levels of THg and As were found in cord blood (Med((THg))=5.8 ng/g; Med((As))=3.3 ng/g) and breast milk (Med((THg))=0.6 ng/g; Med((As))=0.8 ng/g) from Greek women, while the highest Se levels were found in cord blood (Med=113 ng/g) from Italy. Significant linear correlations were found between Hg, Se and As in blood, cord blood and breast milk. In addition, significant relations were found between the frequencies of total fish consumption and biomarkers of As, MeHg and Se exposure, with the strongest Spearman rank coefficients between frequencies of total fish consumption and THg levels in cord blood (r(s)=0.442, p<0.001) or THg levels in hair (r(s)=0.421, p<0.001), and between frequencies of total fish consumption and As levels in cord blood (r(s)=0.350, p<0.001). The differences in Hg and As exposure between countries were probably due to different amounts of fish consumption and the consumption of different species of fish of different origin, while the highest Se levels in women from Italy were probably the consequence of the more frequent consumption of different non specific food items. Moreover, fish consumption, the possible common source of As, Hg and Se intake, could explain the correlations between the elements determined in cord blood, mothers blood or breast milk.

Blood cadmium, mercury, and lead in children: an international comparison of cities in six European countries, and China, Ecuador, and Morocco.

Childrens blood-lead concentration (B-Pb) is well studied, but little is known about cadmium (B-Cd) and mercury (B-Hg), in particular for central Europe. Such information is necessary for risk assessment and management. Therefore, we here describe and compare B-Pb, B-Cd and B-Hg in children in six European, and three non-European cities, and identify determinants of these exposures. About 50 school children (7-14 years) from each city were recruited (totally 433) in 2007-2008. Interview and questionnaire data were obtained. A blood sample was analyzed: only two laboratories with strict quality control were used. The European cities showed only minor differences for B-Cd (geometric means 0.11-0.17 μg/L) and B-Pb (14-20 μg/L), but larger for B-Hg (0.12-0.94 μg/L). Corresponding means for the non-European countries were 0.21-0.26, 32-71, and 0.3-3.2 μg/L, respectively. For B-Cd in European samples, traffic intensity close to home was a statistically significant determinant, for B-Hg fish consumption and amalgam fillings, and for B-Pb sex (boys higher). This study shows that European city childrens B-Cd and B-Pb vary only little between countries; B-Hg differs considerably, due to varying tooth restoration practices and fish intake. Traffic intensity seemed to be a determinant for B-Cd. The metal concentrations were low from a risk perspective but the chosen non-European cities showed higher concentrations than the cities in Europe.

Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses

Previous analyses at the European scale have shown that cadmium and lead concentrations in mosses are primarily determined by the total deposition of these metals. Further analyses in the current study show that Spearman rank correlations between the concentration in mosses and the deposition modelled by the European Monitoring and Evaluation Programme (EMEP) are country and metal-specific. Significant positive correlations were found for about two thirds or more of the participating countries in 1990, 1995, 2000 and 2005 (except for Cd in 1990). Correlations were often not significant and sometimes negative in countries where mosses were only sampled in a relatively small number of EMEP grids. Correlations frequently improved when only data for EMEP grids with at least three moss sampling sites per grid were included. It was concluded that spatial patterns and temporal trends agree reasonably well between lead and cadmium concentrations in mosses and modelled atmospheric deposition.

Heavy metal and nitrogen concentrations in mosses are declining across Europe whilst some “hotspots” remain in 2010

In recent decades, naturally growing mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals and nitrogen. Since 1990, the European moss survey has been repeated at five-yearly intervals. In 2010, the lowest concentrations of metals and nitrogen in mosses were generally found in northern Europe, whereas the highest concentrations were observed in (south-)eastern Europe for metals and the central belt for nitrogen. Averaged across Europe, since 1990, the median concentration in mosses has declined the most for lead (77%), followed by vanadium (55%), cadmium (51%), chromium (43%), zinc (34%), nickel (33%), iron (27%), arsenic (21%, since 1995), mercury (14%, since 1995) and copper (11%). Between 2005 and 2010, the decline ranged from 6% for copper to 36% for lead; for nitrogen the decline was 5%. Despite the Europe-wide decline, no changes or increases have been observed between 2005 and 2010 in some (regions of) countries.

Mercury and other elements in lichens near the INA Naftaplin gas treatment plant, Molve, Croatia

This paper describes the use of epiphytic lichens as bioindicators for spatial monitoring of mercury and other elements in air near the natural gas treatment facilities at Molve, Croatia. It is well known that at this location the concentration of mercury in natural gas is very high and therefore it has to be removed from natural gas before further processing in order to prevent technological and environmental problems. In order to monitor the efficiency of an industrial facility for removal of mercury from natural gas, mercury measurements in air and lichens were performed during 9 months in 1997/1998. In situ lichens Parmelia sulcata, Xantoria parientina and Hypogymnia physodes and transplanted lichen species Hypogymnia physodes were used. A good correlation between mercury concentrations in air and lichens was found. The concentrations of barium and bromium were also significantly elevated in transplanted lichens, most probably related to technological process at the gas treatment plant and/or other geological factors. It was confirmed that lichens can successfully be used as bioindicators, provided a careful experiment is designed, particularly the amount of lichens transplanted, the duration of exposure and the initial levels and homogeneity of transplanted lichens.

Multi-element atmospheric deposition study in Croatia

For the first time the moss biomonitoring technique and two complementary analytical techniques − neutron activation analyses (NAA) and atomic absorption spectrometry (AAS) − were applied to study multi-element atmospheric deposition in the Republic of Croatia. Moss samples were collected during the summer of 2006 from 98 sites evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention - ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. Conventional and epithermal NAA and AAS made it possible to determine concentrations of 41 elements including key toxic metals such as Pb, Cd, Hg, and Cu. Factor analysis (Principal component analysis with varimax rotation) was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. For the elements included in the European programme, the median values for Croatia were generally around the average median values observed in Europe. The Adriatic coastline of Croatia may be considered as an environmentally pristine area. This study was conducted in order to provide a reliable assessment of air quality throughout Croatia and to produce information needed for better identification of pollution sources and improving the potential for assessing environmental and health risks in Croatia associated with toxic metals.

Cadmium, mercury and lead in the blood of urban women in Croatia, the Czech Republic, Poland, Slovakia, Slovenia, Sweden, China, Ecuador and Morocco

ObjectivesThe aim of the study was to make an international comparison of blood levels of cadmium (B-Cd), lead (B-Pb) and mercury (B-Hg) of women in seven European, and three non-European cities, and to identify determinants.Materials and MethodsAbout 50 women (age: 46–62) from each city were recruited (totally 480) in 2006–2009. Interview and questionnaire data were obtained. Blood samples were analysed in one laboratory to avoid interlaboratory variation.ResultsBetween the European cities, the B-Pb and B-Cd results vary little (range of geometric means: 13.5–27.0 μg/l and 0.25–0.65 μg/l, respectively); the variation of B-Hg was larger (0.40–1.38 μg/l). Between the non-European cities the results for B-Pb, B-Cd and B-Hg were 19.2–68.0, 0.39–0.99 and 1.01–2.73 μg/l, respectively. Smoking was a statistically significant determinant for B-Cd, while fish and shellfish intakes contributed to B-Hg and B-Pb, amalgam fillings also contributed to B-Hg.ConclusionsThe present results confirm the previous results from children; the exposure to lead and cadmium varies only little between different European cities suggesting that other factors than the living area are more important. The study also confirms the previous findings of higher cadmium and lead levels in some non-European cities. The geographical variation for mercury is significant.

Relationship between the prenatal exposure to low-level of mercury and the size of a newborn’s cerebellum

Exposure to methylmercury at any stage of central nervous system development could induce alterations and result in severe congenital abnormalities. Total mercury level in maternal hair during pregnancy correlates well with blood levels of methylmercury and with total mercury levels in fetal brain. A prospective study has been conducted and a total of 137 childbearing women living at the coastal region with term, normal pregnancies were included and their newborns evaluated by ultrasonography. Mothers and their newborns are divided in two groups according to their hair mercury levels; examined group with high body levels of mercury (≥ 1 μg/g) and control group with low body levels of mercury (<1 μg/g). Neurosonographic examination was conducted to all newborns. Two dimensions of cerebellum in the sagital-medial plane have been measured: maximum height and width starting from the roof of the fourth chamber. Majority of mothers had hair mercury levels lower than 1 μg/g (N = 107). Mean value was 0.88 μg/g (SD 1.24), ranging from 0.02 to 8.71 μg/g. There was no significant difference between the two groups when it comes to the width of cerebellum (Mann-Whitney test: Z = 1471; p = 0.141). However, comparison related to the length of cerebellum shows statistically significant smaller cerebellum in newborns whose mother had hair mercury levels higher than 1 μg/g (Mann-Whitney test: Z = 2329; p = 0.019). Our results lead to a conclusion that prenatal exposure to, what we consider to be, low-levels of methylmercury does influence fetal brain development detected as decreased size of newborns cerebellum. From a clinical point of view, a question related to the influence of prenatal low-level methylmercury exposure on fetal neurodevelopment remains open. Our further objectives are to direct the research towards performing detailed neuropshychological tests on children at the age of 18 months. Such tests could indicate the presence of subtle neurological or neuropsychological deficits.

Neurodevelopmental effects of low-level prenatal mercury exposure from maternal fish consumption in a Mediterranean cohort: study rationale and design.

Background Mercury is a neurotoxic environmental pollutant. However, the literature on the neurodevelopmental effect of low-level prenatal mercury exposure from maternal fish intake is inconsistent. We assessed the association between prenatal mercury exposure and infant neurodevelopment in coastal areas of 4 Mediterranean countries. Methods This was a prospective cohort study that planned to enroll approximately 1700 mother–infant pairs. Pregnant women and their newborn children were recruited in selected hospitals of the study areas. Biological samples, including maternal hair and cord blood, were collected from mothers and children, and the concentrations of mercury and other elements were measured. Exposures to lifestyle, environmental, and social factors were assessed through questionnaires. The main outcome was child neurodevelopment at 18 months, as measured by the Bayley Scales of Infant and Toddler Development, Third Edition. Conclusions This cohort has a number of strengths. First, mercury concentration was measured in several biological samples, which allows for a better understanding of mercury kinetics and is useful for sensitivity analyses. Therefore, we expect to be able to adjust for the potential confounding effects of lifestyle and social factors and for the effects of other elements that were measured in the biological samples. Finally, this is a multinational study and thus permits assessment of the relation between mercury and child neurodevelopment in different populations.