Comparison of different digestive tract models for estimating bioaccessibility of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) from red slag 'Kieselrot'.

'Kieselrot' (red slag), a highly PCDD/F-contaminated leaching residue from a copper production process, has been used as surface layer for more than 1,000 sports fields, playgrounds and pavements in Germany and neighbouring countries. Children can ingest this material directly by hand-to-mouth activities or soil-pica behaviour. Furthermore secondary contamination of farm land or kitchen gardens by drift of red slag dust may lead to an enrichment of PCDD/F within the food-chain.

Impact of silver and copper on the survival of amoebae and ciliated protozoa in vitro.

The efficacy of 1:10 silver/copper combinations for inactivation of Hartmannella vermiformis amoebas and the ciliated protozoan Tetrahymena pyriformis in vitro was studied. Tetrahymena and Hartmannella/isolate 19 were inactivated for 2 log steps by 100 + 1000 micrograms/l Ag + Cu. Hartmannella/isolate 21 was more resistant.

Decrease of PCDD/F levels in human blood--trend analysis for the German population, 1991-1996.

More than 500 whole blood samples of normal subjects from Germany collected in 1991-1996 have been analyzed for polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) by capillary gas chromatography/high-resolution mass spectrometry. Over the examined time period a continuous decrease of the PCDD/F concentrations in human blood was observed. The mean levels found were about 42.

Decrease of PCDD/F levels in human blood from Germany over the past ten years (1989-1998).

744 whole blood samples of normal subjects from Germany collected in 1989-1998 have been analyzed for polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) by capillary gas chromatography/high resolution mass spectrometry. Over the examined time period a continuous decrease of the PCDD/F concentrations in human blood was observed. The mean levels found were 43.

Myeloperoxidase-catalyzed formation of PCDD/F from chlorophenols.

Chlorophenols (CP) are transformed in vitro to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) by a biochemical-catalyzed oxidation. This is shown for 2,4,5-tri-, 2,3,4,6-tetra-and pentachlorophenol with myeloperoxidase recovered from human leucocytes in the presence of hydrogen peroxide. The yield, the reaction, and the PCDD/F-pattern found depend on the CP.

Four years of experience with silver-copper ionization for control of legionella in a german university hospital hot water plumbing system.

Silver-copper ionization was used for controlling Legionella distribution in a German university hospital hot water plumbing system for 4 years. In the beginning, silver concentrations were not allowed to exceed 10 microg/L because of drinking water regulation limits in Germany. Water samples were monitored for Legionella counts, temperature, and silver and copper concentrations.

Peroxidase-catalyzed in vitro formation of polychlorinated dibenzo-p-dioxins and dibenzofurans from chlorophenols.

Chlorophenols (CP) are transformed in vitro to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) by a peroxidase-catalyzed oxidation. This is shown for 2,4,5-tri-, 2,3,4,6-tetra- and pentachlorophenol with plant horseradish peroxidase and with myeloperoxidase recovered from human leukocytes, each in the presence of hydrogen peroxide. The yield, the reaction and the PCDD/F-pattern found are dependent on the CP.

Human fecal PCDD/F-excretion exceeds the dietary intake.

A mass balance of human dietary PCDD/F-intake and fecal PCDD/F-excretion was carried out. The participants of the study were seven male and seven female adults between the ages of 24 to 64 years, living in North Rhine-Westphalia, Germany. The PCDD/F-intake was measured using the duplicate method.

Comparison of free-living amoebae in hot water systems of hospitals with isolates from moist sanitary areas by identifying genera and determining temperature tolerance.

Legionella-contaminated hot water systems and moist sanitary areas in six hospitals were sampled for amoebae by following a standardized collection protocol. Genus identifications and temperature tolerance determinations were made. Amoebae identified as Hartmannella vermiformis (65%), Echinamoebae spp.

Levels of PCDD/PCDF in blood fat as indices of the PCDD/PCDF body burden in humans.

The levels of PCDD/F in blood fat are similar to those in body fat and in milk fat of lactating women. Therefore, the levels of PCDD/F in blood fat can be used as an index of the individual PCDD/F body burden in humans. In order to evaluate the PCDD/F background exposure levels of the German population, blood samples collected from 95 subjects (age 12-82 years) living in a rural area of North-West Germany were analysed for PCDD/F.

Mobilization of PAH and PCB from contaminated soil using a digestive tract model.

Environmental contaminants are mainly incorporated by ingestion. In general only those contaminants mobilized by the digestive juices are available for absorption in the digestive tract, while pollutants still fixed to indigestible particles leave the body without any effect. To evaluate the different health risks arising from the ingestion of individual types of polluted soil or other materials, we developed an in vitro test system which simulates the transition of pollutants from contaminated materials into digestive juices by means of a standardized artificial gastro-intestinal model.

[Effect of silver and copper ions on survival of Legionella pneumophila in tap water].

In vitro studies were performed to give information about the required metal concentrations in decontaminating Legionella-loaded warm water systems with the electrochemical generation of Ag+ and Cu2+ ions. The influence of Ag and Cu ions, as single compounds and in combination, on the survival of Legionella pneumophila (serogroup 6) was determined in tap water at 45 degrees C. Marked differences were detected in the action of these metals.

Gas chromatographic determination of trace amounts of vinyl chloride and dichloroethenes in landfill-gas.

A method for the determination of vinyl chloride (VC) and dichloroethenes (DCE) in gas samples is presented. The analytes are preconcentrated from a gas-volume of up to 20 l on an adsorption tube filled with 1.0 g of a carbon molecular sieve at a flow rate of 80 l/h and are subsequently desorbed with carbon disulfide.

[Dioxin level of small volume gardeners in Duisburg].

The PCDD/F levels were determined in the venous blood of 21 allotment gardeners in Duisburg (Germany). Soil analyses had shown elevated levels of PCDD/F in garden soil (range 16.4-77.

[Digoxin content in blood lipids of children, athletes, sports ground attendants and residents after content with dioxin-containing surface slag (Kieselrot)].

In 1991 it was discovered, that a large number of sporting grounds and playgrounds in Germany were covered with a waste slag material from a former copper smelter located at Marsberg, Germany. This material was found to contain high levels of PCDD/F ranging up to 100,000 TE/kg. The objective of the present study was to assess whether subjects sporting on such grounds had elevated levels of PCDD/F in blood.

[Volatile organochlorine compounds in human tissue].

Between November 1978 and June 1979 a total of 150 tissue sample (subcutaneous adipose tissue, perinephric fat, liver, lung and muscle tissue) from 30 autopsy cases were examined for their content of volatile organic chlorinated compounds. The ages of the deceased ranged from 29 to 82 years, whereas the majority was 60-70 years old and most were male. Volatile organic chlorinated compounds are detected in all tissue samples investigated.

[Effect of pesticides on the release of histamine, chemotactic factors and leukotrienes from rat mast cells and human basophils].

The influence of pesticides on mediator release from rat peritoneal mast cells and human basophiles was studied. Mediators from mast cells and basophils are important factors in allergic and inflammatory reactions. Release of histamine from rat mast cells and human basophils is demonstrated by stimulation with dieldrin, DDT, heptachlor, heptachlorepoxid and biphenyl.

[A method for detection of volatile organic halogenated compounds in human and animal tissues (author's transl)].

A method is described which is suitable for detecting volatile halogenated hydrocarbons boiling from 60 degrees to 150 degrees C in human and animal tissues. Fried tissue samples of 10 grams are homogenized with Na2SO4. Stripped by nitrogen in an 80 degrees C water bath the compounds are sorbed on XAD-2 columns and desorbed by pentane.

[Nitrate and nitrite in human food calculation of the daily intake and its range (author's transl)].

Daily intake of nitrate and nitrate by German Federal Republic resident was calculated to 75 mg NO3- and 3.3 mg NO2-. These results are based on values mainly obtained by analyses of prepared meals of an area which was supplied with nitrate free drinking water.

[Nitrate and nitrite in prepared meals in relation to the nitrate concentration of drinking water (author's transl)].

The nitrate and nitrite content of prepared foods was investigated in four areas in Rhineland Palatinate. The nitrate content of the drinking water was different in each area, the first region always having less than 1 mg NO-3/litre, the second an average of 19.5 mg NO-3/litre, the third an average of 35.

[Bacterial growth in the perfusion medium of the isolated rat brain and its inhibition by antibiotics].

In the perfusion medium of the isolated rat brain the bacterial content was examined. The perfusion medium used contained 30% bovine erythrocytes, 2 g% bovine serum albumin and about 13 mM glucose in Krebs-Henseleit-solution. Before the perfusion of the isolated rat brain was started the medium recirculated up to two hours in the perfusion apparatus.