Sublethal Effects of Trace Metals (Cd,Cr, Cu,Hg) on Embryogenesis and Larval Settlement of the Ascidian <Emphasis Type="Italic">Ciona intestinalis</Emphasis>

Toxicity of Cadmium (Cd), Chromium (Cr), Copper (Cu), and Mercury (Hg) on the early developmental stages of Ciona intestinalis was investigated. Developmental defects of larvae after exposure of gametes throughout their development to the larval stage were assessed. Gamete exposure to increasing metal concentrations resulted in a significant decrease of the percentage of normally hatched larvae, showing median effective concentrations (EC₅₀) of 721 g/L (6.42 M) for Cd, 12772 g/L (226 M) for Cr, 36.6 g/L (0.576 M) for Cu, and 44.7 g/L (0.223 M) for Hg. Larval attachment was significantly affected when gametes were exposed to the metals throughout development. The EC₅₀ reducing larval attachment by 50% were 752 g/L (6.7 M) for Cd, 15026 g/L (289 M) for Cr, 67.8 g/L (1.607 M) for Cu, and 78.1 g/L (0.389 M) for Hg. Therefore, on a molar basis Hg is three times more toxic than Cu, 20–30 times more than Cd, and 700–1000 times more toxic than Cr, for both responses.     

Human exposure to volatile halogenated hydrocarbons from the general environment

Summary The objective of this study was to assess individual human exposure to volatile halogenated hydrocarbons (VHH) under normal environmental conditions by means of biological monitoring, i.e. by the measurement of these compounds or their metabolites in body fluids, such as blood, serum, and urine. Blood samples of 39 normal subjects without known occupational exposure to these agents were examined for the occurrence of VHH. The following compounds were present in quantifiable concentrations in 60 to 95% of the blood samples examined: chloroform (median 0.2 g/l; range < 0.1–1.7 g/l), 1,1,1-trichloroethane (median 0.2 g/l; range < 0.1–3.4 g/l), tetrachloroethylene (median 0.4 g/l; range < 0.1–3.7 g/l). Trichloroethylene could be detected in 31% of all blood samples (median < 0.1 g/l; range < 0.1–1.3 g/l). In addition, the levels of trichloroacetic acid (TCA) were determined in serum and 24-h urine samples of 43 and 94, respectively, normal subjects. TCA was present in measurable concentrations in all serum and urine samples examined. The median of the TCA levels in serum was 21.4 g/l (range 4.8–221.2 g/l) and in urine 6.0 g/24 h (range 0.6–261.4 g/24 h). The results are discussed in relation to data from the literature on human exposure to VHH from the general environment, i.e. via air, food, and water. The upper normal limits calculated from the results of this investigation can be used to detect even minor excessive exposures to VHH.     

Mercury and methylmercury in population risk groups on the Atlantic coast of Southern Spain

The presence of methylmercury and total mercury in the hair of high risk groups residing in the highly industralized South Atlantic coastal area of Spain were studied. In fishermen, total mercury and methylmercury content showed slight non-statistically significant differences among groups from two different coastal areas (geometric means: 10.41 and 8.36 g/g for total mercury; 8.28 and 6.72 g/g methylmercury). Mercury content in both groups differed significantly from controls (geometric mean 2.5 g/g total mercury, 4.50 g/g for methylmercury; p<0.05). In pregnant women, statistically significant differences were found in the three groups (two coastal areas and controls). Geometric means were 2.40, 5.94, and 0.94 g/g for total mercury and 1.93, 4.78, and 0.82 g/g for methylmercury. Results were compared with those obtained in other European countries in the Mediterranean area. Simultaneously, the same compounds were analyzed in fish and molluscs from those most consumed by people in the above-mentioned groups. The following results were obtained: sword fish, 1.57±1.27 g/g and 1.20±0.94 g/g for total mercury and methylmercury respectively; Scrobicularia plana, 0.07±0.052 and 0.053±0.039 g/g; Tapes decussatus, 0.046±0.20 and 0.039±0.018 g/g.     

X-irradiation effects on growth and metamorphosis of gastropod larvae (Crepidula fornicata): A model for environmental radiation teratogenesis

Little information is available on the effects of x-irradiation on the development of multicellular marine organisms. Larvae of the marine gastropodCrepidula fornicata were irradiated at 200 rad/min, 250 kVp x-rays, to doses between 500 and 20,000 rad in a single fraction. During the weeks following exposure, changes in shell length and biomass, incidence of metamorphosis to the juvenile stage of development, and mortality were measured. The results over a 20-day period demonstrated a dose-dependent decrease in growth rate of larval shells following doses above 2,000 rad (control at day 20=850±110 m length, 820±11 m for 500 rad, 750±30 m for 2,000 rad, 710±30 m for 5,000 rad, 620±30 m for 10,000 rad, and 580±15 m for 20,000 rad). Shell length-specific biomass was significantly decreased for doses above 10,000 rad. A significant increase in larval mortality was detected with doses above 2,000 rad. The cumulative percent of larval metamorphosis was decreased by exposures to 5,000 rad and was detectable as early as 18 days after irradiation; however, metamorphosis of larvae after 5,000 rad occurred faster by day 21 while other groups metamorphosis required 34–35 days for completion.Crepidula fornicata may provide a very sensitive and convenient system in which to study teratogenic effects of x-irradiation on multicellular organisms.     

Increase in the amount of erythrocyte δ-aminolevulinic acid dehydratase in workers with moderate lead exposure

Summary The amount of ALA-D in human erythrocytes was determined directly by radioimmunoassay or calculated from the restored activity assayed in the presence of zinc and dithiothreitol, and a good correlation was observed between the RIA-based and the restored activity-based amounts.The RIA-based amount of ALA-D in the blood of 10 normal individuals (blood lead levels of 5.6 ± 2.3 g/100 ml: mean ± SD) and 19 lead-exposed workers (blood lead levels of 41.2 ± 10.2 g/100 ml) was 54.1 ± 11.8 g/ml blood and 92.3 ± 20.6 g/ml blood, respectively, indicating an apparent increase of the enzyme amount in lead-exposed workers.A significant increase in the amount of erythrocyte ALA-D calculated from the restored activity in lead-exposed workers was observed even in the low blood lead level of 10–20 g/100 ml, resulting in the range of blood lead level 20–40 g/100 ml. No significant difference was observed in hematocrit and hemoglobin content between lead-exposed and non-exposed groups. These observations suggested that the increase of erythrocyte ALA-D in lead exposure was not due to anemia, which might result in the increase of young erythrocytes in peripheral blood.This increase in the amount of ALA-D in human erythrocytes might be a result of the function to overcome the inhibition of the enzyme in bone marrow cells during lead exposure, and these findings may throw light on the danger to human health of low-level lead toxicity.Abbreviations ALA-D -Aminolevulinic acid dehydratase or 5-Amnoevulinic acid hydro-lyase, EC 4.2.1.24 - ALA -Aminolevulinic acid - Rc Reticulocyte - RIA Radioimmunoassay - DTT Dithiothreitol Supported in parts by Science Research Fund of the Ministry of Education, Science and Culture of Japan and by Research Grant of Fujiwara Foundation of Kyoto University     

The effects of poly chlorinated biphenyls and methylmercury,singly and in combination on mink. II: Reproduction and kit development

Adult ranch-bred mink (Mustela vison) were fed diets containing either 0, 1.0 g/g polychlorinated biphenyls (PCB) (Aroclor^® 1254), 1.0 g/g methylmercury (MeHg), a combination of 1.0 g/g PCB plus 1.0 g/g MeHg, or 0.5 g/g PCB plus 0.5 g/g MeHg. Fertility of adult male mink, percentage of females whelped or number of kits born per female were not affected by the treatments. However, growth rate of kits nursed by mothers exposed to 1.0 g/g PCB was significantly reduced. There was a synergistic effect of PCB and MeHg which reduced kit survival in groups receiving both chemicals simultaneously. Kit survival to weaning in the control, 0.5 g/g PCB/MeHg, and 1.0 g/g PCB/MeHg groups was 72.0%, 62.7% and 35.8%, respectively. The results suggest that growth and survival of mink kits are adversely affected at dietary levels of PCB and MeHg currently present in some environments.     

Monitoring lead pollution near a storage battery recycling plant in Taiwan, Republic of China

This study presents the distribution of blood lead levels and lead in various environmental samples (water, sediments, soils, and air) near the Shing-Yie storage battery recycling plant in Taiwan before (July 1990 to June 1991) and after (July 1992 to June 1993) amelioration. Before amelioration, the average blood lead levels in the neighborhood of the plant were in the range of 10.55±5.7 to 12.28±7.9 g/dl. After amelioration, relatively lower average concentrations of blood lead (range 8.35±3.0 to 9.13±2.5 g/dl) were generally found; however, these averages were still higher than that (7.79±3.5 g/dl) from other lead-unpolluted areas of Taiwan. An exceedingly high geometric mean (GM) lead concentration (128 g/L) was found in the downstream river water of the Tawulum River passing by the plant. The concentrations of lead (GM=372 and 418 g/g) in the downstream river sediments were higher than those (GM=123 and 158 g/g) in the upstream river sediments before and after amelioration, respectively. Furthermore, lead species in river sediments were analyzed by a sequential leaching technique. The sum of phases I, II, and III accounted for 83.7% of total lead at station R₂ (nearest to the plant). Maximum lead concentration (GM=2402 g/g) in dust at the soil surface from station S₁ (nearest to the plant) was much higher than those from the other stations by about 18 times before amelioration. However, the maximum value dropped to 1,155 g/g after amelioration. On the whole, the geometric mean concentration of lead in dust at the soil surface nearest to the plant was >1,000 g/g and decreased to <100 g/g in the 15–30 cm depth soil about 2 km away from the plant. Before amelioration, the geometric mean lead concentration of 4.57 g/m³ (range 0.102–37.6 g/m³) in the air near the plant was higher than that at the background locations, the geometric mean value of which was 0.08 g/m³.     

Chronic toxicity and bioaccumulation of 2,5,2′,5′- and 3,4,3′,4′-tetrachlorobiphenyl and Aroclor® 1242 in the amphipodHyalella azteca

The addition of 100 (g/L of Aroclor^® 1242 (A1242) or 2,5,2,5-tetrachlorobiphenyl (TeCB) during 10 week chronic toxicity tests withHyalella azteca resulted in complete mortality. There were no effects on survival, growth, or reproduction after addition of 30 g/L. Toxic effects were observed at tissue levels of between 30 and 180 g/g on a wet weight basis, and tissue levels appear to be a better indicator of toxicity than levels in water. No toxic effects were observed after additions of up to 2,700 g/L of the coplanar congener 3,4,3,4-TeCB.H. azteca has the ability to avoid accumulating in excess of 140 g/g 3,4,3,4-TeCB. The amount taken up was proportional to the amount added in water up to 100 g/L, but was constant at higher additions, possibly accounting for its relatively low toxicity. The low toxicity of the coplanar congener, as compared to the non-coplanar 2,5,2,5-TeCB, is in direct contrast to the high toxicity of coplanar PCB congeners to mammals and may be associated with slower rates of aromatic hydrocarbon metabolism in amphipods. Polychlorinated biphenyl levels measured in amphipods from Lake Ontario are approximately 100-fold below levels associated with toxicity inH. azteca, but are above levels which, through biomagnification up the food chain, lead to salmonid residues in excess of 2 g/g, a tolerance limit for human consumption.     

Cadmium,zinc, copper,and metallothionein levels in the kidney and liver of inhabitants of Upper Silesia (Poland)

Summary The levels of Cd, Zn, Cu and metallothionein (MT) were determined in renal cortex and liver of 75 subjects deceased in the period 1986–1989 in the area of Upper Silesia (Katowice). The mean age of the population studied was 53.6 ± 14.6 years. The determined levels (mean ± SD) were: 43.1 ± 23.5 g Cd/g; 52.5 ± 17.4 g Zn/g; 2.2 ± 0.7 g Cu/g; 0.80 ± 0.36 mol Hg/g in renal cortex and 3.5 ±2.5 pg Cd/g; 82.8 ± 34.3 g Zn/g; 4.5 ± 2.6 g Cu/g; 0.69 ± 0.44 pmol Hg/g in the liver. The level of Cd in renal cortex was 40% higher in smokers compared to nonsmokers and was independent of the gender. Whole-body retention of Cd was 34.1 ± 18.5 mg; smoking elevated the value from 27.1 to 38.2 mg. Compared with a similar study made in central Poland (ód), a significant difference was found only regarding the level of Zn and MT in the liver, pointing to the possibility that exposure to this element in the region of Upper Silesia may be higher.This work has been supported by the grant CPBR 11.12(C-56/86) from the Institute of Rural Medicine, Lublin, Poland     

In vitro susceptibility of mycelial and yeast forms of Penicillium marneffei to amphotericin B,fluconazole, 5-fluorocytosine and itraconazole

The mycelial (25°C) and yeast-like (37°C) forms of Penicillium marneffei clinical and type strains were investigated for their in vitro susceptibility to amphotericin B (AmB), 5-fluorocytosine (5-FC), fluconazole (FLU) and itraconazole (ITZ), using Bacto antibiotic medium 3, yeast-nitrogen, Sabouraud's dextrose (pH 5.7) and high resolution (pH 7.1) broth media (1ml/tube), respectively. Results indicated that the minimal inhibitory and minimal fungicidal concentrations (MICs and MFCs) for the mycelial cultures of P. marneffei to AmB were in the range 0.78–1.56 and 0.78–3.125 g/ml, respectively, as against 3.125–25 g (MICs) for the yeast form cultures. The MFCs to AmB for the yeast form were one dilution higher. The MICs to FLU were generally lower for the yeast form (6.25–25 g) than the mycelial form (25–50 g/ml), whereas MFCs for the mycelial cultures were > 100 g as compared to 6.25–100 g for their yeast form. The MICs for the mycelial form to 5-FC ranged from < 0.195–0.39 g. Higher MICs (6.25 g) were recorded for their yeast form. The MFCs to 5-FC for the yeast form were 25–100 g/ml. The MICs for the mycelial form to ITZ ranged from < 0.195 to 3.125 g/ml. Higher values (< 0.195–50 g) were recorded for their yeast-like form. The MFCs to ITZ for mycelial and yeast forms ranged from < 0.195–0.39 and 25–100 g/ml, respectively. Results indicate that P. marnefei's yeast form is more sensitive to FLU and ITZ (8 of 10 strains) while the mycelial form displayed greater susceptibility to AmB and 5-FC. The MICs for ITZ remained steady in SD medium, pH 5.7 to 7.1. However, some strains gave higher MIC values (0.39–1.56 g/ml) when tested in the HR.     

Copper/Metal Ratios in the Gills of Rainbow Trout (Oncorhynchus mykiss) Provide Evidence of Copper Exposure Under Conditions of Mixed-Metal Exposure

Previous work has suggested that the ratio of copper residues to zinc in the gills of rainbow trout may indicate short-term exposure to increased levels of waterborne copper. However, the effect of exposure to a combination of increased copper and zinc concentrates in the water column was unknown. We exposed rainbow trout to 8 ± 2 g L^–1, 40 ± 2 g L^–1 and 90 ± 9 g L^–1 of waterborne copper and 21 ± 3 g L^–1, 129 ± 40 g L^–1, and 202 ± 40 g L^–1 of waterborne zinc in a 2-factor experiments and gill copper and zinc residues were examined. Other gill parameters analyzed included the concentrations of calcium, magnesium, sodium, and potassium, liver copper and zinc concentrations and plasma copper, calcium, sodium, and potassium are also reported here. Copper residues in the gill filaments were significantly higher in the highest level of copper exposure (high Cu, 4.06 g g^–1; low Cu 2.41 g g^–1; 0 Cu 2.01 g g^–1; P = 0.001), whereas no differences were seen in zinc concentrations at any treatment level. Gill sodium and plasma calcium concentrations were also decreased at the highest waterborne copper concentrations. Although copper–zinc ratios in the gills were significantly different between the highest and lowest copper treatments (P = 0.002, F = 6.59), copper–sodium and copper–magnesium ratios were more sensitive to waterborne copper exposure (P = 0.001, F = 17.91 and P = 0.002, F = 15.45, respectively). These copper–metal ratios may be better indicators of copper loading in the water column.     

Biological and environmental monitoring of occupational exposure of pharmaceutical plant workers to methotrexate

Summary The exposure of 11 pharmaceutical plant workers to methotrexate (MTX) was studied. Personal air samples were taken during the different manufacturing processes: drug compounding, vial filling, and tablet preparation. The uptake of MTX was established by the determination of MTX in urine. MTX was analyzed using the fluorescence polarization immunoassay (FPIA), a method that is frequently used for monitoring serum levels in patients treated with MTX. The FPIA method was modified in such a way that MTX could be measured quickly and efficiently in air and urine samples. MTX was detected in air samples of all workers except for those involved in the vial filling process (range: 0.8–182 g/m³; median: 10 g/m³). The highest concentrations were observed for workers weighing MTX (118 and 182 g/m³). MTX was detected in urine samples of all workers. The mean cumulative MTX excretion over 72–96 h was 13.4 g MTX-equivalents (range: 6.1–24 g MTX-equiva g MTX-equivalents (range: 6.1–24 g MTX-equivalents). lents). A significantly lower background level of 10.2 g A significantly lower background level of 10.2 g MTX-equivalents was measured in urine of 30 control persons (range: 4.9–21 g MTX-equivalents).     

Relationship between inhibition of erythrocyte pyrimidine 5′-nucleotidase activity and biological response for porphyrin metabolism in workers occupationally exposed to lead

Summary A rapid determination of erythrocyte pyrimidine 5-nucleotidase (P5N) activity in lead workers was carried out using a high-performance liquid chromatograph (HPLC). The P5N activity had a good negative correlation with the concentration of lead in blood (PbB) ranging from 16 to 96 g/dl (r = -0.82, n = 77). Further, the P5N was compared with other biological parameters: erythrocyte -aminolevulinic acid dehydratase (ALAD) activity, erythrocyte protoporphyrin (PROTO), urinary -aminolevulinic acid (ALA) and urinary coproporphyrin (COPRO).The correlation coefficients between P5N and ALAD, log PROTO, log ALA, and log COPRO were 0.59, –0.72, –0.65, and –0.61, respectively. On the other hand, the normal value of P5N obtained from 72 healthy subjects was 11.9 ± 2.1 units; ol uridine/h/g Hb (mean ± SD), indicating that the lower limit of 95% confidence interval for normal P5N was about 8 units. When P5N was cut off at 8 units in 77 lead workers, the validity (sensitivity + specificity) for PbB 40 g/dl, PbB 60 gg/dl, erythrocyte PROTO 150 g/dl RBC, urinary ALA 6 mg/l, and urinary COPRO 150 g/l was 1.66, 1.76, 1.57, 1.68, and 1.60, respectively. From these results, it was confirmed that the erythrocyte P5N test is suitable for the biological monitoring of exposure to lead in a wide range, and its activity is useful in predicting the disturbance of porphyrin metabolism induced by lead.     

Nickel uptake and loss in the bivalvesCrassostrea virginica andMytilus edulis

Nickel uptake and loss byCrassostrea virginica andMytilus edulis were studied at naturally occurring seawater temperatures and salinity to determine their potential as indicators of nickel pollution. After 12 wks treatment with 5 and 10 g Ni/kg seawater, mean tissue concentrations inC. virginica were 9.62 ±3.56 and 12.96 ±5.15 g/g dry weight. Mean nickel concentrations inM. edulis treated with 5 and 10 g Ni/kg seawater for 12 wks were 10.40 ±2.66 and 16.43 ±3.19 g/g dry weight, respectively. Significant linear relationships were found between nickel uptake byC. virginica andM. edulis and seawater nickel concentrations over the concentration range. A significant inverse relationship exists between tissue nickel concentration and dry weight in bothC. virginica andM. edulis. After holding nickel-treatedM. edulis in ambient flowing seawater for 28 weeks, a 73 and 89% loss of nickel concentration occurred inM. edulis treated with 5 and 10 g Ni/kg, respectively. When treated similarly,C. virginica from both the 5 and 10 g Ni/kg treatments lost 48 and 68% respectively, of their tissue nickel concentration. The evidence suggests thatM. edulis would be a better indicator of nickel pollution in its environment thanC. virginica.Contribution #341     

A new HPLC fluorimetric method to monitor urinary delta-aminolevulinic acid (ALA-U) levels in workers exposed to lead

Summary A new sensitive HPLC method for the determination of urinary delta-aminolevulinic acid (ALA-U) was used to evaluate the relationship between blood-lead (Pb-B) and ALA-U levels in male workers exposed to lead. The differences between the ALA-U levels determined by this method (ALAU-HP) and by a colorimetric method (ALA-U-CL) are discussed. The HPLC method gave values similar to the ALA-U-CL values at high ALA-U level. However, at low blood-lead levels (58 ± 22 g/l, n = 23), the mean ALA-U-HP level corrected by urinary creatinine level was one-third of the corrected ALA-UCL level (0.83 ± 0.14 and 2.4 ± 0.5 mg/g creatinine, respectively). A significant increase of the mean corrected ALA-U-HP level was observed at 162 ± 22 g/l Pb-B (P < 0.05, n = 26), while that of ALA-UCL was observed at 245 ± 30 g/l Pb-B (P < 0.01, n = 37). The regression equation based on the logistic model fitted well to the relationship data between the Pb-B level and the percentage of the subjects with corrected ALA-U-HP above the cut-off point (1.12 mg/g creatinine) and the expected Pb-B level for 50% response was 270 g/l Pb-B, while it did not fit well to the relationship data between Pb-B level and the percentage of the subjects with corrected ALAU-CL above the cut-off point (3.5 mg/g creatinine). The maximum responses for the two sets of corrected ALA-U levels were both observed at 625 ± 25 g/l. The corrected ALA-U level by HPLC method seems to be a useful indicator for biological monitoring of exposure to lead at low levels (< 400 g/l Pb-B = health-based biological limit, WHO) as well as high ones.     

Dislodgeability of pesticides from products made with recycled pesticide container plastics

Products containing high density polyethylene plastic from recycled pesticide containers were tested for levels of dislodgeable pesticide under dry and damp conditions. Trifluralin was found to be the pesticide released in largest quantity from plastic curbstops. Levels dislodged ranged from 0.18 g/100 cm² to 4.18 g/100 cm² for all plastics tested. Significantly higher dislodgeability occurred from products where low density polyethylene plastics were used to dilute pesticide container plastics, compared to products containing only pesticide container plastics. Amounts of trifluralin dislodged by wiping with dry cheesecloth for 15 min were 0.83±0.50, 3.52±0.40, and 2.53±0.56 g/100 cm² for products containing 100%, 50%, and 25% pesticide container plastics, respectively. Respective levels of trifluralin dislodged with saline-dampened cheesecloth were 2.00±0.71, 3.21±0.82, and 1.16±0.51 g/100 cm². Decreased amounts of trifluralin were released after product weathering, with levels dislodged under dry conditions of 0.007±0.002, 0.0083±0.001 and 0.0089±0.001 m/100 cm², respectively. Similar studies of asphalt products containing recycled pesticide containers found the average amounts of trifluralin and 2,4-D iso-octyl ester dislodged were 0.33 g/100 cm² and 1.35 g/100 cm², respectively. Pesticide levels dislodged from all products tested were within acceptable daily intake levels. Calculations of margins of safety showed exposure to products made with recycled containers would not present an unacceptable risk to individuals coming in contact with them.     

Placental transfer of lead,mercury and cadmium in women living in a rural area

Summary The influence of the lead content of drinking water on the transplacental transfer of lead was investigated in 70 pregnant women living in a rural area of Belgium. The mothers were divided into 2 groups: group A: morning water lead below 50 g/liter; group B: morning water lead above this value. In group A, the mean lead content of water was 11.8 g/liter and in group B it amounted to 247.4 g/liter.The difference in the mean lead concentration between the two groups were for maternal blood: 3.2 g/100 ml, for umbilical cord blood: 3.3 g/100 ml, and for placenta: 3.6 g/100 g. These differences are statistically significant.There were significant correlations between water lead and lead concentration in blood (mother, newborn) or placenta. An increment of water lead concentration from 50 to 500 g/liter increases blood lead concentration in mother and in newborn by about 3 g/100 ml and in placenta by about 2.5 g/100 g (wet weight).     

Kybernetische Probleme der Arbeitsmedizin

Zusammenfassung Bei 35 klinisch gesunden, hitzebelasteten Arbeitnehmern eines Stahlwerkes wurden Mineral- und Spurenelementanalysen im Blut durchgeführt. Als Vergleichskollektiv dienten 20 Schwerarbeiter des gleichen Betriebes, die nicht hitzeexponiert waren. Die Untersuchungen ergaben für die Hitzearbeiter (für das Vergleichskollektiv) folgende Mittelwerte und Standardabweichungen: Natrium: 327,50±14,98 mg- % (323,98±5,28 mg-%) Kalium: 13,29±1,49 mg-% (15,31±1,10 mg-%) Calcium: 7,91±0,74 mg-% (9,25±1,19 mg-%) Magnesium:1,91±0,28 mg-% (1,60 ± 0,28 mg-%) Blei: 24,31±8,40 g-% (14,37±3,26 g-%) Nickel: 1,56± 1,27 g-% (2,28±0,67 g-%)Die Differenzen zwischen beiden Gruppen sind, mit Ausnahme von Natrium, für alle untersuchten Elemente statistisch signifikant. Sie lassen sich mit einem durch Hypovolumämie des Körperkerns ausgelösten kompensatorischen Hyperaldosteronismus erklären. Dieser Schutzmechanismus betrifft nur den Natriumhaushalt. Die hohen Kaliumverluste werden selbst durch kaliumreiche Getränke nicht voll ausgeglichen.

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Cybernetic problems of industrial medicineIII. Analyses of minerals and trace elements in the blood of heavy workers chronically exposed to heat

Summary Good health and productivity of men are essentially dependent of climatic factors. Mainly in iron- and steel-industry a broad spectrum of oppressing environmental circumstances is to be found. Changes in the household of minerals and trace minerals, concerning the adaptation of human organism to high environmental temperatures play an important part, especially because these changes effect the bodily charge. Aim of this work was to show the effects of chronical, thermic stress at the place of employment on the household of minerals and trace minerals.With blood of 35 healthy, heatexposed workers of a steel factory mineral and trace mineral analyses were performed. As a comparison 20 heavy workers of the same factory were chosen who were not heatexposed. The results of the analysis gave the following mean ratios and standard deviation for the heatworkers (for the compared collective): sodium: 327.50±14.98 mg-% (323.98±5.28 mg-%) potassium: 13.29±1.49 mg-% (15.31±1.10 mg-%) calcium: 7.91±0.74 mg-% (9.25±1.19 mg-%) magnesium: 1.91 ±0.28 mg-% (1.60±0.28 mg-%) lead: 24.31±8.40 g-% (14.37±3.26 g-%) nickel: 1.56±1.27 g-% ( 2.28±0.67 g-%)The differences between both groups are statistically significant for all analysed elements, except sodium. This could be explained by a compensatoric hyperaldosteronism, caused by a hypovolumia of the body nucleus. This protective mechanism only concerns the household of sodium. The high losses of potassium are not fully compensated even not by drinks being rich with potassium.

     

Cytogenetic studies of herbicide interactions in vitro and in vivo using atrazine and linuron

The herbicides atrazine and linuron, found in Wisconsin's groundwater, were tested alone and in combination, both in vivo and in vitro, to determine their individual and combined genotoxic effects. Human lymphocytes exposed in vitro to either 1 g/ml linuron or 0.001 g/ml atrazine showed little chromosome damage, whereas significant chromosome damage was observed in lymphocytes simultaneously exposed to 0.5 g/ml linuron and 0.0005 g/ml atrazine, suggesting at least an additive model. In another experiment, mice were fed 20 g/ml atrazine, 10 g/ml linuron, or a combination of 10 g/ml atrazine and 5 g/ml linuron in their drinking water for 90 days, after which bone marrow cells and cultured splenocytes were examined for chromosomal damage. None of the treatment groups showed chromosome damage in bone marrow, whereas the cultured splenocytes demonstrated damage in all treatment groups. These experiments suggest that, prior to assessing the risk of a herbicide, it may be necessary to test it in combinations which mimic the mixtures which would occur under field conditions, such as in contaminated groundwater.     

Effects of 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) injected into the yolks of chicken (Gallus domesticus) eggs prior to incubation

The yolks of White Leghorn chicken (Gallus domesticus) eggs were injected prior to incubation with either 3,3,4,4,5- pentachlorobiphenyl (PCB 126) at doses ranging from 0.1 to 12.8 g/kg egg or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at doses ranging from 0.04 to 0.64 g/kg egg. Chicks were subjected to necropsy within 24 h of hatching. The brain, bursa, heart, liver, and spleen were removed and weighed. Assessment of the rate of hatching indicated an LD₅₀±S.E. of 2.3±0.19 g/kg egg (7.1±0.58 nmol/kg egg) for PCB 126 and 0.15±0.012 g/kg egg (0.47±0.037 nmol/kg egg) for TCDD. No significant differences in the incidence of developmental abnormalities (structural defects and edema) were observed in TCDD-exposed embryos, while PCB 126 caused significantly more developmental abnormalities at 3.2, 6.4, and 12.8 g/kg egg than the vehicle control. PCB 126 caused lower hatchling weights and greater relative brain, heart, and liver weights when compared to the vehicle control group at a dose of 3.2 g/kg egg which is greater than the LD₅₀. TCDD at 0.08 g/kg egg caused relative bursa weights to be less than those of the vehicle control. A toxic equivalency factor (TEF) of 0.07 was determined for PCB 126 in relation to TCDD based on overt lethality.