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Biomedical subjects

M Lodenius

Publications and source records attributed to M Lodenius.

18 recordsLinked to original sources
PubMed2003

Exchange of mercury between atmosphere and vegetation under contaminated conditions.

Adsorption and desorption of mercury was studied under laboratory conditions using moss (Sphagnum girgensohnii) and Rye grass (Lolium perenne) at different temperatures. Desorption was also studied in a transplantation experiment. The adsorption was rapid and strong for both plant species at different temperatures (+10 to +60 degrees C) and exposure times (1 h, 1 month) while the evaporation was negligible. Also the leaching of adsorbed mercury was of minor importance. The results emphasise the importance of vegetation in removal of mercury from the atmosphere. They also confirm the suitability of moss and grass for biomonitoring purposes. The high retention of mercury in moss even at +60 degrees C indicates the possibility of using higher temperatures in pretreatment of samples for mercury analyses.

Adsorption↗
PubMed2001

Heavy metal solubility in podzolic soils exposed to the alkalizing effect of air pollutants.

The heavy metal content of pine forest soil was studied near the boundary between Russia and Estonia, an area characterized by large amounts of acidic and basic air pollutants, mainly sulfur dioxide and calcium. Alkalization dominates the processes in soil, since sulfur is adsorbed only in small quantities, and calcium is much better adsorbed. In addition to Ca, great amounts of Al, Fe, K, and Mg are accumulated in the humus layer due to air pollution. The heavy metal content has increased. The exchangeable content of heavy metals was in many cases much higher in polluted alkaline soils than in non-polluted acidic soils, even the ratio of exchangeable to total metal content being higher in alkaline plots. To avoid a dangerous increase in soluble heavy metal content, it is important to decrease not only the large sulfur emissions of local pollutant sources, but also the alkaline pollutants. A similar concern must be taken into account when liming of acidic forest soils is planned.

Air Pollutants↗
PubMed1998

Mercury in the Amazon.

Release and spreading of mercury from gold mining is a widespread problem in the Amazon area. Today we have rather good knowledge of the mercury situation. Tens of investigations have considered mainly concentrations in fish and human hair. Metallic mercury is used for amalgamation of gold, and the mercury is released by evaporation at reburning sites. The first extraction (burning) is performed in the field at the garimpos and the second (reburning) in gold shops in towns. This practice may cause severe exposure to elemental mercury by inhalation for people working with gold purification. Mercury is also released in substantial amounts to rivers and lakes. This mercury may be bioaccumulated as methylmercury in aquatic food chains. Predatory fish often contain mercury in concentrations that far exceed the safety norms in Brazil. As many people eat fish daily, there is a high exposure to methylmercury. Neurological disorders have been found in exposed persons. Methylmercury concentrations in hair are often at levels that may cause clinical symptoms of Minamata disease. The greatest health hazard index values have been estimated for people eating contaminated fish.

Animals↗
PubMed1998

Determination of pesticide residues in some major food crops of northern Tanzania.

The residue levels of DDE, DDT, Dieldrin, Endosulfan and Lindane were determined in beans, maize and wheat samples collected from local markets in northern Tanzania. All residue levels were far below the FAO/WHO standards. No significant correlations were detected among the pesticides studied or between pesticides and the fat content of the commodities.

Fabaceae↗
PubMed1996

The effects of simultaneous large acidic and alkaline airborne pollutants on forest soil.

The effects of air pollutants on soil were studied in Scots pine (Pinus sylvestris L.) forests near the boundary of Russia and Estonia. The study area is characterized by large amounts of acidic and basic pollutants, mainly sulphur dioxide (SO(2)) and calcium (Ca). Several variables were measured in different horizons of the podzolic soil polluted by emissions from local sources in areas of several thousands of square kilometers. Alkalinization dominates the processes in the soil, since sulphur is absorbed only in small quantities and Ca is much better absorbed. Ca content in humus horizon may rise even to 100 000 mg kg(-1) and the pH of originally very acidic soil may rise to 8.3. Total aluminum (Al) content was high in the heavily polluted plots, since emissions contain much Al. On the other hand, the exchangeable Al was very low in these alkaline sites. A larger quantity of exchangeable Al occurred farther from the pollutant sources, even though total Al in these plots was low. These plots had acidic soils in which Al is in exchangeable form. Due to the neutralizing effect of acidic and basic pollutants, forest damage in the study area was not as serious as might be supposed. Complicated pollutant situations must be taken into consideration when pollution-caused environmental protection measures are planned. It is not reasonable to reduce only SO(2) emissions, but necessary to lower the basic emissions at the same time.

Journal Article↗
PubMed1995

Human hair mercury levels in Tucuruí area, State of Pará, Brazil.

The environmental mercury contamination at the Tucuruí water reservoir was studied by measuring the amount of mercury in human hair samples collected from fishermen and their families. Samples were also collected from the Parakanã Indian reservation in the vicinity to give information about the background levels in the area. The mercury concentrations in hair samples ranged from 0.9 to 240 mg/kg. The mean value in the main reservoir was 65 mg/kg. Seven values exceeded 100 mg/kg and 31 values exceeded 50 mg/kg. The hair Hg concentrations amongst the fishermen in Tucuruí reservoir are high enough to cause health effects. The fetal exposure is especially alarming. Changes in gold mining practises and in the human diet are recommended.

Adult↗
PubMed1987

Heavy metal levels in two biennial pine insects with sap-sucking and gall-forming life-styles.

The concentrations of cadmium, copper, nickel and lead were studied in two biennial pine insects in relation to the deposition of heavy metals in the environment around the industrialised town of Harjavalta in southwestern Finland. Sap-sucking pine bark bugs, Aradus cinnamomeus (Heteroptera, Aradidae), and gall-forming pine resin gall moths, Petrova resinella (Lepidoptera, Tortricidae) were collected on sample plots located at logarithmic distances along 9 km-long transects from the distinctive emission source. The responses of these insects representing different life-style were compared. Heavy metal concentrations in A. cinnamomeus were highest (Cd 17 microg g(-1), Cu 1900 microg g(-1), Ni 220 microg g(-1), Pb 32 microg g(-1)) in the vicinity of the factor complex, and lowest in the outermost zones. This trend followed a linear regression model. The pattern was less clear in P. resinella, the concentrations being only one-tenth of those recorded in A. cinnamomeus. Correlations between metal levels in A. cinnamomeus and previously examined Sphagnum moss bags proved to be highly significant in every case. The differences in the heavy metal concentrations of these two insect species, which occupy the same trophic position, would appear to be due to the differences in their feeding characteristics. Heavy metals accumulate in the posterior bulb of the midgut in the discontinuous alimentary system of A. cinnamomeus, while P. resinella is likely to secrete most of the metals into the walls of the galls. The almost total absence of these two insect species near the factory complex seems to be associated with the high concentrations of metals.

Journal Article↗