The influence of soil characteristics on the extractability of Cd, Pb and Zn in upland and moorland soils.

A study was undertaken to investigate the feasibility of using existing data sets of total soil metal concentrations and soil parameters, such as pH, to predict available metal concentrations on a regional or national basis. The attraction of such an approach is that it would provide valuable data for initiatives requiring information on the availability and mobility of metals in soils without the need for costly soil sampling and analysis. Ninety-seven topsoil and subsoil samples were collected from 6 soil series in a catenary sequence in north Wales to provide data for the development of an empirical model. These were analysed for total, 0.01 M CaCl2-extractable and porewater metal concentrations and for a range of soil properties including pH, solid and dissolved organic matter and cation exchange capacity. Regression analysis showed that, of the soil parameters measured, pH was the most important predictor variable for the estimation of CaCl2-extractable Cd, Pb and Zn. pH accounted for up to 86% of the variance in the proportion of 'total' metals which were extracted by CaCl2, a reagent that is commonly used to estimate plant uptake of elements. However, the relationships recorded between soil parameters and Kd (total metal/porewater metal) were much weaker, indicating that porewater metal concentrations can less readily be predicted from total soil metal concentrations and soil properties.

Dispersion of As and selected heavy metals around a coal-burning power station in central Slovakia.

A power station in central Slovakia emitted arsenic (As) in large quantities for over 30 years as a result of burning As-rich brown coal. Nowadays emissions of As are low. Over the lifetime of the plant's operation over 3000 tonne of As have been emitted into the environment. This paper aims to examine the concentrations of As in the soil around the power station, and also to investigate whether the coal burnt in the plant, and consequently the emissions from it, contained raised levels of six further heavy metals. Soil concentrations were compared to ground level air As concentrations predicted by an air dispersion model. Coal samples were taken from the power station and analysed to determine concentrations of As, Zn, Pb, Cu, Cr, Ni and Cd. Soil samples (n=113) were taken up to 12 km from the plant along a transect designed to follow the valley floor in which the power station is situated. Soil samples were analysed for concentrations of those elements for which coal was tested. Concentrations of As in coal were high (AM 518 mug/g). Those of other heavy metals were, in general, low. Concentrations of soil As were substantially raised in the near vicinity of the plant but decreased within 5 km to concentrations similar to those in the rest of the district. Overall, levels within 10 km of the plant were slightly above those recommended for residential levels in the UK. Soil concentrations of other heavy metals were higher in the vicinity of the plant but none, overall was raised. Comparison of results from a previous air dispersion model of ground level air arsenic concentrations showed a moderate correlation (r=0.6) between modelled and measured values. Over its period of operation the power plant has contributed to raised levels of soil As in the local soils, though not substantially of other elements. Though now airborne As emissions are controlled, concern remains regarding soil arsenic concentrations and fugitive emissions from the plant that could be contributing to exposure of the local population and of the workforce.

Contractile and endothelium-dependent dilatory responses of cerebral arteries at various extracellular magnesium concentrations.

To clarify the effect of extracellular magnesium (Mg2+) on the vascular reactivity of feline isolated middle cerebral arteries, the effects of slight alterations in the Mg2+ concentration on the contractile and endothelium-dependent dilatory responses were investigated in vitro. The contractions, induced by 10(-8)-10(-5) M norepinephrine, were significantly potentiated at low Mg2+ (0.8 mM v. the normal, 1.2 mM). High (1.6 and 2.0 mM) Mg2+ exhibited an inhibitory effect on the contractile responses. No significant changes, however, in the EC50 values for norepinephrine were found. The endothelium-dependent relaxations induced by 10(-8)-10(-5) M acetylcholine were inhibited by high (1.6 and 2.0 mM) Mg2+. Lowering of the Mg2+ concentration to 0.8 mM or total withdrawal of this ion from the medium failed to alter the dilatory potency of acetylcholine. The changes in the dilatory responses also shifted the EC50 values for acetylcholine to the right. The present results show that the contractile responses of the cerebral arteries are extremely susceptible to the changes of Mg2+ concentrations. In response to contractile and endothelium-dependent dilatory agonists, Mg2+ probably affects both the calcium influx into the endothelial and smooth muscle cells as well as the binding of acetylcholine to its endothelial receptor. Since Mg2+ deficiency might facilitate the contractile but not the endothelium-dependent relaxant responses, the present study supports a role for Mg2+ deficiency in the development of the cerebral vasospasm.

Trace element concentrations in the fruit peels and trunks of Musa paradisiaca.

Chemical analyses for the elementary compositions of the ashes of the fruit peels and trunks of the tropical plantain Musa paradisiaca have been undertaken. The elements, categorized as trace elements, generally are found to have higher mean concentrations in the fruit peels than in the trunks (except in the case of Zn). Their peel-trunk uptake ratios have been calculated and range between 1 and 4, showing normal levels of accumulations in the fruit peels over the trunks.

Investigating urban geochemistry using Geographical Information Systems.

Geographical Information System (GIS) is an interactive digital extension of the two-dimensional paper map. Customised maps are created by the selection and aggregation of data from independent sources to assist studies in urban geochemistry. The metropolitan area of Wolverhampton, in the West Midlands, UK is used to illustrate the types of output that can be generated. These include: geographic and geological feature; geochemical data and land use. Multi-layered maps can be used to investigate spatial relationships, for example, between elevated concentrations of metals in soils and industrial land use. Such maps can also be used to assist the assessment of potential exposure of groundwater, ecosystems and humans using maps incorporating guideline values for metals in soils.

Platinum metal concentrations in urban road dust and soil in the United Kingdom.

Concentrations of Pt, Pd, Rh and Au in soils and road dusts taken from areas of high and low traffic flows in the London Borough of Richmond and from a section of the Kingston bypass (A3) at New Malden, Surrey, have been measured. High concentrations of platinum are associated with high traffic densities. Samples taken from streets of lower traffic flows were found to contain the lower concentrations of the ranges. These values correlated well with the levels of lead which were also high at roundabouts. If the preliminary results obtained in this study apply more generally throughout the UK, then the potential for exposure to enhanced levels of Pt would appear to be higher for road users and for those living in urban environments or along major highways.

Assessment of environmental arsenic levels in Prievidza district.

A coal-burning power station in the Nitra Valley in central Slovakia annually emitted large quantities of arsenic (up to 200 tonnes) between 1953 and 1989. Since then, pollution-control measures have reduced arsenic emissions to less than 2 tonnes a year. However, the power station was still a source of airborne arsenic pollution. As part of an EU-funded study on exposure to arsenic and cancer risk in central and Eastern Europe we carried out a study of environmental levels of arsenic in the homes and gardens of residents of the district. Garden soil samples (n=210), house dust samples (n=210) and composite house dust samples (n=109) were collected and analysed using inductively coupled plasma atomic absorption spectroscopy (ICP-AES) at Imperial College. The mean arsenic content of coal and ash in samples taken from the plant was 519 microg/g (n=19) and 863 microg/g (n=22), respectively. The geometric mean (GM) arsenic concentration of garden soils was 26 microg/g (range 8.8-139.0 microg/g), for house dust 11.6 microg/g (range 2.1-170 microg/g) and for composite house dust 9.4 microg/g (range 2.3-61.5 microg/g). The correlation between the arsenic levels in soil and in house dust was 0.3 (P<0.01), in soil and composite house dust 0.4 and house dust and composite house dust 0.4 (P<0.01 for both), i.e., were moderate. Arsenic levels in both house dust and soil decreased with distance from the power station. Overall, levels in both fell by half 5 km from the point source. Weak correlations were seen between the total urinary arsenic concentrations and arsenic concentrations in composite house dust.

Regional differences in nitric oxide-dependent vascular responses to somatostatin.

The mechanisms of the vascular effects of somatostatin (ST) are not well known. This study compares the direct effect of ST in different vascular regions and species. Isolated perfused segments of the cat superior mesenteric artery in vitro did not exhibit a vascular response in the resting state, however, ST-induced vasodilatation was observed with norepinephrine preconstriction. In contrast, ST only slightly dilated superior mesenteric vein segments. In the artery, NG-nitro-L-arginine inhibited both ST and endothelium-dependent nitric oxide (NO) mediated response. No regular dose-response curves were found when ST was applied on the large mesenteric artery in the cat, but rings of small mesenteric artery from both cats and dogs exhibited dose-dependent relaxations. These effects were also NO-dependent. Local application of ST on the rat saphenous artery in situ elicited NO-mediated dose-dependent vasodilatation. However, ST constricted rat saphenous veins in the case of either adventitial or intraluminal application. It is concluded that ST exerts different actions on the arterial and the venous vessel wall. The major response in arteries is endothelium-mediated vasodilatation seen in various species and vascular beds. Large and small arteries respond differently to ST but these differences require further elucidation.

Changes in lead concentrations in the home environment in Birmingham, England over the period 1984-1996.

Data for lead concentrations reported in Birmingham prior to 1984 were reviewed and thought to be not strictly comparable in these surveys due to various sampling and analysis methodologies. A survey was implemented to compare the concentrations of lead for 1984/1985 with those of 85 houses re-sampled within the city in 1996. It is shown that lead concentrations and loading of dusts in and around the houses have fallen significantly over the last 11 years. However, lead concentrations in soils have only slightly decreased over the same period. The US EPA IEUBK model for exposure of children to lead is validated, updated and applied to predict the blood lead level of young children. It is predicted that the blood lead concentrations of 2-year-old children have been reduced considerably over the period. The fall in lead concentrations is thought to be the consequence of the reduction policies for lead emissions in the UK since the 1980s. The result of this study provides a valuable example of the benefits of the reduction policies for lead which are of equal importance in developing countries with rapid economic growth.

The solid-solution partitioning of heavy metals (Cu, Zn, Cd, Pb) in upland soils of England and Wales.

Ninety-eight surface soils were sampled from the uplands of England and Wales, and analysed for loss-on-ignition (LOI), and total and dissolved base cations, Al, Fe, and trace heavy metals (Cu, Zn, Cd, Pb). The samples covered wide ranges of pH (3.4-8.3) and LOI (9-98%). Soil metal contents measured by extraction with 0.43 mol l-1 HNO3 and 0.1 mol l-1 EDTA were very similar, and generally lower than values obtained by extraction with a mixture of concentrated nitric and perchloric acids. Total heavy metal concentrations in soil solution depend positively upon soil metal content and [DOC], and negatively upon pH and LOI, values of r2 ranging from 0.39 (Cu) to 0.81 (Pb). Stronger correlations (r2=0.76-0.95) were obtained by multiple regression analysis involving free metal ion (Cu2+, Zn2+, Cd2+, Pb2+) concentrations calculated with the equilibrium speciation model WHAM/Model VI. The free metal ion concentrations depend positively upon MHNO3 and negatively upon pH and LOI. The data were also analysed by using WHAM/Model VI to describe solid-solution interactions as well as solution speciation; this involved calibrating each soil sample by adjusting the content of "active" humic matter to match the observed soil pH. The calibrated model provided fair predictions of total heavy metal concentrations in soil solution, and predicted free metal ion concentrations were in reasonable agreement with the values obtained from solution-only speciation calculations.

Mechanism of hemoglobin-induced spasm in the isolated middle cerebral artery of the cat.

a./Great regional differences were observed in the vasospastic effect of hemoglobin. Namely, hemoglobin was far more potent in the middle cerebral artery than in the mesenteric artery. b./The role of potassium ions as well as activation of calcium mobilizing adrenergic, serotoninergic and PGF2 alpha smooth muscle receptors were excluded in the mechanism of cerebral vasospasm induced by hemoglobin. c./First in the literature we showed that atropine significantly attenuates the vasospastic effect of hemoglobin, and hemoglobin releases peptidergic neurotransmitters and modulators from nerve terminals that are located in the adventitia of the middle cerebral artery.

Regional differences in the regulation of contraction-relaxation machinery of vascular smooth muscle.

In the present study we revealed substantial differences in the regulation of the contraction-relaxation machinery of the middle cerebral and mesenteric arteries. a. Although K+-Krebs solution resulted in similar contractile responses in both vascular beds, norepinephrine, serotonin and PGF2 alpha were more potent in inducing contraction in the mesenteric artery than in the middle cerebral artery. Contrary, extremely high concentrations of acetylcholine produced negligible contractions in the mesenteric artery as compared to the middle cerebral artery. b. In more than 50% of the cases a considerable spontaneous tone developed in the middle cerebral artery, which was not due to the activation of adrenergic alpha receptors or some arachidonic acid metabolite. A similar phenomenon never occurred in the mesenteric artery. c. Acetylcholine, adenosine triphosphate and adenosine brought about similar dilatory concentration-response curves in the middle cerebral artery, but greatly different ones in the mesenteric artery where acetylcholine was the most, adenosine triphosphate the least potent dilator.

[Hemodynamic effect of plasma DNA]. / Gemodinamicheskii éffekt DNK plazmy krovi.

To reveal the hemodynamic effect of plasma DNA, the authors measured the concentrations of plasma DNA, the length of its molecular fragments, and hemodynamic resistance/Toms effect. The Toms effect was detected in all blood samples from 10 healthy donors and 39 patients without acute stroke caused by atherosclerosis of the head great arteries with and without arterial hypertension. There was a clear inverse relationships between the plasma concentrations of DNA which had only long-molecular fragments in healthy persons and the hemodynamic resistance of its blood flow samples. The patient blood plasma had significant increased DNA concentrations but their molecular fragments were long and short. Inverse relationships between the plasma DNA concentration and the hemodynamic resistance of the patients' blood flow samples had a less correlation coefficient due to the high proportion of short DNA molecular fragments. The Toms effect was shown in the DNA solution prepared only from human funic blood where the DNA molecular fragments were long. The Toms effect was absent in the solutions prepared from the commercial cattle or salmon sperm DNA which contained shorter DNA molecular fragments. It is concluded that plasma DNA has a hemodynamic effect and the origin of long-molecular fragments of DNA which is typical for healthy young persons and short DNA molecular fragments that additionally appear in patients with vascular disorders is different.

[Data obtained by prenatal diagnosis of maternal age dependence of fetal chromosomal anomalies]. / Tapasztalati adatok a magzati kromoszóma elváltozások anyai korfüggéséröl prenatális diagnosztika kapcsán.

The connection between fetal chromosomal anomalies and advanced maternal age is well established. Theoretical calculations derived from incidence data and the expected ratio of Down's syndrome babies born to mothers between the age of 35-39 and from 40-45 indicate that fetal kariotyping is necessary at the maternal age of 35 or above. Based on 668 prenatal chromosomal studies (both on cultured amniotic cells and direct preparation of the trophoblast obtained by chorionic villus sampling) authors come to the conclusion that all pregnant women above the age of 35 should undergo fetal karyotyping (in order to detect 22% of the conceptuses with a chromosomal defect) since the incidence rate of abnormal fetal karyotype was found 6.08% between 35-39 years, and 8.49% between 40-45 years of maternal age. To achieve this target about 7500 prenatal karyotyping should be performed per year the laboratory and clinical backgrounds of which should be created.

[Significance of hyper-echogenic yolk sac in first-trimester screening for chromosome aneuploidy]. / A hyperechogen szikhólyag jelentósége a kromoszóma aneuploidiák elsó trimeszterbeli ultrahangszúrésében.

Recently, the measurement of the thickness and extent of the first-trimester posterior simple embryonic hygroma by vaginal ultrasound has become the most efficient method in the antenatal screening for chromosomal aneuploidies. The sensitivity of the screening is only 75-90%, therefore, the search for other potential (sonographic) markers is needed in order to increase the efficiency. Ultrasound measurement of the echogenicity and the diameter of yolk sac and the thickness of dorso-posterior simple embryonic hygroma was carried out in 3620 first-trimester pregnancies between 9-11 weeks. A total of 105 embryos with simple hygroma of > or = 3 mm and 39 pregnancies with abnormal, hyperechogenic yolk sac of 1.8-4.0 mm in diameter were detected. Cytogenetic analysis through chorionic villi samples revealed chromosomal aneuploidies in 52 cases. In 19 of 3620 pregnancies both hyperechogenic yolk sac and first trimester simple hygroma were present. Each of these 19 pregnancies were chromosomally abnormal. Hyperechogenic yolk sac alone was present in another 20 pregnancies with otherwise normal fetal findings. The authors could not accomplish sonographic identification of the yolk sac in 42 pregnancies. In conclusion, combined presence of hyperechogenic yolk sac plus first-trimester simple hygroma of 3 mm or more in the same pregnancy is highly associated with chromosomal aneuploidy between the 9-11 gestational weeks.

[Genetic counseling and prenatal care after medications during the first trimester]. / Genetikai tanácsadás és gondozás elsó trimeszterbeli gyógyszerszedés miatt.

Analysis of the outcome of 127 pregnancies with first trimester medication (8.4% of the total number of the patients seeking genetic advice in 1997 at the Institute of Medical Genetics in Szeged) was carried out. The gestational age at the time of the medication and genetic counselling, the indications of the treatment, the drugs, the estimated fetal risk, and results of genetic ultrasound examinations and pregnancy outcome were evaluated. The majority of pregnant woman (78%) asked for genetic counselling before the 12. gestational week. The main indications the treatment were: infections, psychiatric-neurologic (depression, anxiety, epilepsy), endocrine (diabetes, hyperthyreoidism), and cardiovascular diseases and gastrointestinal problems. The main groups of the drugs were: antibiotics, antipyretic-, antidepressive-, antidiabetic- and antihypertensive drugs. When the multiple medication was conducted by simultaneous administration of two or more drugs, a complex risk calculation was performed. The fetal risk was higher than 10% in 31 cases (24%). The ultrasound examinations performed by qualified sonographer contributed to a correct evaluation and to reliable follow-up of pregnancies. No suspicious ultrasound finding was reported in the first trimester. However, a severe fatal brain malformation was found in a second trimester pregnancy, which was terminated by the couple's request in the 18th gestational week. A complete follow-up was obtained in 70.9% (90) of the cases. Out of 64 pregnancies intended to continue to term 4 fetal malformations were found. Of them three malformations (patent ductus arteriosus, Robin sequence and a ventricular septal defect) were explored at birth or in the newborn period. The actual 6.3% of fetal malformations was higher compared to the rate expected at birth, but almost equal to the rate of congenital malformation found up to the end of the first year of age in Hungary.

[Feto-maternal transfusion following cordocentesis]. / Foetomaternalis transzfúzió cordocentesis kapcsán.

Invasive intrauterine diagnostic procedures may be followed by feto-maternal transfusion. The authors studied the feto-maternal transfusion after cordocentesis. 199 women underwent fetal umbilical cord blood sampling for fetal karyotyping in weeks 15-26. Maternal serum alpha-fetoprotein level was measured before and after the procedure. The data were statistically analysed by multiple regression analysis and the paired and unpaired Student's t-tests. Twenty percent of more maternal serum alpha-fetoprotein level increase was observed in 73 (36.7%) women. Maximum feto-maternal transfusion was 0.684 ml. The average feto-maternal transfusion was 0.045 ml. No fetal exsanguination was observed. Positive correlation was found between bleeding time after cordocentesis (p = 0.0171) and feto-maternal transfusion as well as the duration of the procedure (p = 0.0275) and feto-maternal transfusion. Negative correlation was found between the amount of fetal blood sample and feto-maternal transfusion (p = 0.0431). The puncture site also influenced feto-maternal transfusion. If the cordocentesis has been performed at the insertion of the cord the feto-maternal transfusion was less than at the free floating umbilical cord (p = 0.0293). Higher feto-maternal transfusion was seen more often after transplacental cordocentesis (p = 0.002). These data suggest that fetomaternal transfusion in the indicator of the difficulty of the procedure.

Urban geochemistry: research strategies to assist risk assessment and remediation of brownfield sites in urban areas.

Urban geochemical maps of Wolverhampton and Nottingham, based on multielement analysis of surface soils, have shown distribution patterns of "total" metals concentrations relating to past and present industrial and domestic land use and transport systems. Several methods have been used to estimate the solubility and potential bioavailability of metals, their mineral forms and potential risks to urban population groups. These include sequential chemical extraction, soil pore water extraction and analysis, mineralogical analysis by scanning electron microscopy, source apportionment by lead isotope analysis and the development of models to predict metal uptake by homegrown vegetables to provide an estimate of risk from metal consumption and exposure. The results from these research strategies have been integrated with a geographical information system (GIS) to provide data for future land-use planning.

[150 years from the birth of Endre Hogyes, promotor of Hungarian medicine]. / Endre Hogyes - Unkarin lääketieteen kehittäjän syntymästä 150 vuotta.

Endre Hogyes, one of the most prominent and internationally known leaders in the field of medical research, a specialist on the treatment of rabies, was born one hundred and fifty years ago in Hungary. E. Hogyes started his medical career and research in 1870. In 1889 he became vice-president of the Royal Hungarian society of Natural Sciences and was elected as member of the Hungarian Academy of Sciences (MTA) and member of the National Council of Public Health. The scientific career of E Hogyes was throughout closely linked to the physiological sciences. He contributed significantly in different fields of the physiological sciences. His most important scientific publications in this field deal with renal physiology, respiratory mechanics, cerebellar function and associated eye movements. Endre Hogyes was the first to organize Hungarian physiologists into a community. The "Special Physiological Conferences" were initiated within the Hungarian Royal Society of Natural Sciences in 1891. As a proof of appreciation, Hungarian physiologists and other medical professionals have proclaimed the year 1997 as a memorial year of Dr. Endre Hogyes.