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).     

Internal lead and cadmium exposure in 6-year-old children from western and eastern Germany

Lead and cadmium levels in blood and deciduous teeth (shed incisors only) of 6-year-old German children were determined in 1991 in a large epidemiological study carried out in rural and urban areas of western Germany (Duisburg, Essen, Gelsenkirchen, Dortmund, Borken) and eastern Germany (Leipzig, Halle, Magdeburg, Osterburg, Gardelegen, Salzwedel). In total, blood lead and cadmium levels of 2311 German children and tooth lead and cadmium levels of 790 German children were analyzed. Blood lead levels were generally low in all study areas with geometric means between 39.3 g/1 and 50.8 g/l in the western German and between 42.3 g/1 and 68.1 g/l in the eastern German study areas. The mean blood lead level of Turkish children (n = 213) living in the western German study areas was 50.1 g/l and thus 5.6 g/1 higher than the overall geometric mean of the western German children. The higher exposure may be explained by a higher oral uptake from food and different living conditions. These children were excluded from multiple regression analysis because they were all living in the western study areas. The mean tooth lead levels ranged between 1.50 and 1.74 g/g in the western and between 1.51 g/g and 2.72 g/g in the eastern study areas. Thus, they show a distribution pattern similar to blood. Blood and tooth lead levels were higher in urban than in rural areas and higher in the eastern German than in the western German study areas. With regard to the blood and tooth cadmium concentrations, no significant differences between the study areas could be found. The mean cadmium levels in blood ranged between 0.12 g/1 and 0.14 g/l and the mean tooth cadmium concentrations between 20.8 ng/g and 27.8 ng/g. Blood and tooth lead and cadmium levels of the eastern and western German children were thus mainly at a relatively low level in all rural and urban study areas. The study demonstrates and confirms that blood and tooth lead levels are influenced by several demographic, social, and environmental variables. The results indicate that there has been a further significant decrease of lead and cadmium exposure in western German children since our last epidemiological study carried out in the same study areas in 1985/1986.     

Toxicity of seleno-L-methionine, seleno-DL-methionine, high selenium wheat, and selenized yeast to mallard ducklings

The toxicity of four chemical forms of selenium (seleno-L-methionine, seleno-DL-methionine, selenized yeast, and high selenium wheat) was compared in day-old mallard ducklings (Anas platyrhynchos). In the first experiment, in which the basal diet was 75% wheat, survival after 2 weeks was lower for ducklings fed 30 g/g selenium as seleno-L-methionine (36%) than for ducklings fed 30 g/g selenium as seleno-DL-methionine (100%) or 30 g/g selenium from high selenium yeast (88%). The concentration of selenium at 2 weeks in the livers of survivors was similar for ducklings fed 15 g/g selenium as seleno-DL-methionine (12 g/g, wet weight), seleno-L-methionine (11 g/g), and high selenium wheat (11 g/g), but was lower when the selenium came from selenized yeast (6.2 g/g). When fed 30 g/g selenium from the various sources, the selenium concentrations in liver were 20 g/g for seleno-DL-methionine, 19 g/g for seleno-L-methionine, and 9.9 g/g for selenized yeast. In a second experiment, in which the basal diet was a commercial duck feed, survival after 2 weeks was 100% in ducklings fed 30 g/g selenium as seleno-DL-methionine, seleno-L-methionine, or selenized yeast. Selenium concentrations in liver were similar for ducklings fed the 30-g/g selenium diets as the DL or L forms of selenomethionine (27 and 25 g/g), but lower for ducklings fed selenized yeast (13 g/g). The greater toxicity of the L form of selenomethionine was probably related to the palatability or nutritional nature of the wheat-based diet used in experiment 1, but the exact reason for the difference between the DL and L forms is unknown. Biologically incorporated selenium, derived from high selenium wheat, was no more toxic than selenium derived from the two purified forms of selenomethionine, and the selenium in selenized yeast was not as toxic as that in the two forms of selenomethionine.     

Effects of mercury,selenium, and organochlorine contaminants on reproduction of Forster's terns and black skimmers nesting in a contaminated Texas Bay

Mean mercury (0.40 g/g), and geometric mean DDE (1.6 g/g) and polychlorinated biphenyl (PCB) (2.3 g/g) concentrations in Forster's tern (Sterna forsteri) eggs from Lavaca Bay were higher than those in tern eggs from a reference area in San Antonio Bay, but residues were not correlated with hatching success. Nest success was similar between bays. Selenium levels in Lavaca Bay tern eggs (0.71 g/g) were also comparable to those in eggs from the reference area (0.68 g/g).Clutch size (3.1 to 3.4) of Lavaca Bay black skimmers (Rynchops niger) was no different than that (3.4) at a reference colony near Laguna Vista. Nest success was similar among three Lavaca Bay colonies, but success was lower at one Lavaca Bay colony (40%) than at Laguna Vista (65%). Mean mercury (0.46 g/g) and selenium (0.75 g/g) concentrations in skimmer eggs from Lavaca Bay were higher than those (0.19, 0.33 g/g) from Laguna Vista; however, concentrations of neither contaminant were related to hatching success. DDE concentrations in Lavaca Bay skimmer eggs (3.4 g/g) were similar to those from Laguna Vista (3.2 g/g) and DDE was negatively correlated with hatching success. PCBs were higher in eggs from Lavaca Bay (1.3 g/g) than Laguna Vista (0.8 g/g). Organochlorine and metal contaminants in most eggs were below embryotoxic levels. Eggshell thinning in Forster's terns (7%) and black skimmers (5%) was below that associated with lowered reproduction.DDE and PCBs were detected in 9 Caspian tern (S. caspia) eggs; maximum concentrations were 4.7 and 5.4 g/g. Caspian tern and least tern (S. albifrons) eggs contained low (0.9 g/g) concentrations of mercury and selenium.     

Effects of tributyltin on survival,growth, morphometry,and RNA-DNA ratio of larval striped bass,Morone saxatilis

Effects of tributyltin (TBT) on survival, growth, morphometry, and RNA-DNA ratio in larval striped bass(Morone saxatilis) were assessed in three experiments. In Experiment I, 13 day old larvae were exposed to 0, 0.067, 0.766, or 2.284 g TBT/L for 6 days. All larvae exposed to 2.284 /L died by day 5; exposure to 0.766 g/L significantly reduced survival relative to controls (59.8% vs. 81.8%). Significant, concentration-dependent decreases in body depth occurred in larvae exposed to 0.067 and 0.766 g/L. In Experiment II, all 16 day old larvae exposed to 1.498 g/L died by day 6. Survival, weight, and morphometry parameters were not significantly different in larvae exposed to 0, 0.052, or 0.444 g/L for 7 days. In Experiment III, survival was similar in 21 day old larvae exposed to 0, 0.055, 0.218, or 0.514 /L for 7 days. Notochord length and dry weight decreased significantly in larvae exposed to 0.514 g/L. Weight and morphometry parameters were more sensitive indicators of sublethal stress than RNA-DNA ratio. Maximum TBT concentrations reported in Chesapeake Bay marinas are likely to cause increased larval mortality. Longer-term studies are needed to assess effects at <0.050 g/L, which may be more representative of habitat conditions.     

Toxicity of mercury,copper, nickel,lead, and cobalt to embryos and larvae of zebrafish,Brachydanio rerio

The toxicity of mercury (HgCl₂), copper (CuCl₂: 5 H₂O), nickel (NiSO₄: 6 H₂O), lead (Pb(CH₃COO)₂: 3 H₂O) and cobalt (CoCl₂: 6 H₂O) was studied under standardized conditions in embryos and larvae of the zebrafish,Brachydanio rerio. Exposures were started at the blastula stage (2–4 h after spawning) and the effects on hatching and survival were monitored daily for 16 days. Copper and nickel were more specific inhibitors of hatching than cobalt, lead, and mercury. Nominal no effect concentrations determined from the dose-response relationships (ZEPs, Zero Equivalent Points) for effect on hatching time were 0.05 g Cu/L, 10 g Hg/L, 20 g Pb/L, 40 g Ni/L and 3,840 g Co/L, and those for effect on survival time were 0.25 g Cu/L, 1.2 g Hg/L, 30 g Pb/L, 80 g Ni/L, and 60 g Co/L. The no effect concentrations for Ni, Hg and Pb are consistent with previously reported MATC values for sensitive species of fish. The no effect concentrations for copper are 1–2 orders of magnitude lower than previously reported values. The major reason for the latter discrepancy was considered to be the absence of organics that can complex copper ions in the reconstituted water that we used, which had a hardness of 100 mg/L (as CaCO₃) and a pH of 7.5–7.7. Unexposed controls were started with embryos from different parental zebrafishes and the parental-caused variability in early embryo mortality, median hatching time and median survival time were estimated.     

Measurement of manganese amelioration of cadmium toxicity inChlorella pyrenoidosa using turbidostat culture

Cadmium (Cd) toxicity and amelioration of Cd toxicity by Mn were measured inChlorella pyrenoidosa, using turbidostat culture. The responses were measured in terms of the maximum specific growth rate, _max, of the populations. In turbidostat culture _max is a dependent variable that can be measured continuously. Cd (as CdCl₂· 2.5 H₂O) was added to control populations at a concentration of 1.8 M Cd. Toxicity was expressed after a 5 generation lag and resulted in a _max steady state 62% lower than the initial control after 2 generations. With continued Cd exposure, Mn (as MnCl₂ · 6H₂O) was then added stepwise to a concentration of 10.4 M Mn which caused a rapid, immediate increase in _max followed by linear increase until a steady-state plateau was reached at a _max 90% of control. The ameliorative response spanned 20 culture generations. After addition of Mn (10.4 M), cellular Cd concentration did not change and cellular Mn concentration increased. Increase in mean cell size accompanied Cd exposure and was significantly decreased when supplemented with 10.4 M Mn. Possible mechanisms of the amelioration are discussed.     

Effects of different dietary levels of cadmium,lead, copper,and zinc on the vitality of the forest pest insect Lymantria dispar L. (Lymantriidae,Lepid)

Lymantria dispar (gypsy moth) larvae were reared on both a natural diet of oak leaves and an artificial medium contaminated independently with four different metal nitrates. Larvae were contaminated up to pupation either from 1st or 4th instars at four concentrations differing by a factor of 5. The lowest concentration levels were 2 g/g Cd, 4 g/g Pb, 10 g/g Cu, and 100 g/g Zn based on nutrient medium dry weight. Developmental rate, growth, mortality and reproductive success were determined. No-Observed-Effect-Concentrations (NOECs) calculated were dependent on the metal, the parameter investigated and the stage at which exposure commenced. In general, larvae exposed from the 4th instar were less susceptible to metal toxification than those exposed from hatching. Considering all parameters investigated, dietary NOECs were determined to be 2 g/g Cd, 4 g/g Pb, 10 g/g Cu, and 100 g/g Zn.     

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.     

A pilot study of lead and cadmium exposure in young children in Stockholm,Sweden: Methodological considerations using capillary blood microsampling

A capillary blood microsampling technique was tested among urban young children in Stockholm. Blood lead (BPb) and hemoglobin (Hb) concentrations were determined in capillary blood obtained by fingerstick from 41 children, 13–20 months old, and the accompanying parent. The quality control included control for lead (Pb) and cadmium (Cd) contamination of material and equipment used for blood sampling, washing procedures for the hands and fingers to be punctured, comparisons of Pb and Cd concentrations in blood obtained by fingerstick and by brachial vein puncture from the same individuals, analysis of external quality control samples for Pb and Cd in blood together with the collected samples, and evaluation of the analytical performance using linear regression analysis.The results showed that blood sampling material may contaminate the blood samples with amounts of Pb and Cd that would seriously influence the monitoring results in the low concentration range (<100 g Pb/L and <1 g Cd/L). However, it is possible to obtain reliable BPb concentrations (>10 g Pb/L), but not BCd concentrations (<1 g Cd/L), with the capillary blood microsampling technique tested provided that a strict quality control is applied. The sampling procedure tested was well accepted by the children and their parents. The children's median BPb concentration (27 g/L; range 9–73 g/L) was similar to the median BPb concentration of their parents (27 g/L; range 7–74 g/L). However, the correlation between child and parent BPb concentrations was poor (R²=0.20), which may indicate different sources to Pb exposure in children and parents.     

Determination of the urinary metabolites of styrene: estimation of the method evaluation function and evaluation of reference values in Danish subjects

Summary A European study on styrene exposure was initiated in 1989 to evaluate the health effects of environmental and occupational exposure. A part of this study included the development of an analytical method for use in a biological monitoring program. The urinary metabolites of styrene, mandelic acid (MA) and phenyl-glyoxylic acid (PGA) were quantitated by a direct and convenient high-performance liquid chromatography method. Urine samples were diluted with eluent and analysed by HPLC with a C₈ reversed-phase column and a buffer to acetonitrile (9:1) eluent with a counterion added. The detector used was a variable UV dectector and the wavelength was = 210 nm. The method was statistically evaluated by a method evaluation demonstrating no systematic error. The uncertainty was 23.8 mol/l and 11.5 mol/l for MA and PGA, respectively. The limit of detection (LOD) of MA is 71.4 mol/l and the LOD of PGA is 34.5 mol/l, sufficiently low for the measurement of styrene exposure at a low exposure level. The present study indicates that reference values for MA and PGA are low. The fraction of reference values below LOD was 0.80 for MA and 0.66 for PGA; consequently, the reference values were described by a non-parametric one-sided tolerance interval. The 95% one-sided upper tolerance limits calculated for MA and PGA were 31.0 mol/mmol creatinine and 20.1 mol/mmol creatinine, respectively, with the coverage 0.95 ±0.045 for both metabolites. The method has been used for biological monitoring in several studies of environmentally and occupationally exposed subjects in concentrations up to 200 mol/mmol creatinine for MA and 150 mol/mmol creatinine for PGA.     

Short-term exposure of zooplankton to the synthetic pyrethroid,fenvalerate, and its effects on rates of filtration and assimilation of the alga,Chlamydomonas reinhardii

In acute tests of toxicity, two cladocerans,Daphnia galeata mendotae andCeriodaphnia lacustris, and the calanoid,Diaptomus oregonensis, were more sensitive to fenvalerate thanDaphnia magna, the organism used in standard laboratory bioassays. The 48-hr EC₅₀s for each species/stage in order of increasing sensitivity were adultD. magna — 2.52 g/L;D. magna (48-hr old) — 0.83 g/L; adultD. galeata mendotae — 0.29 g/L; adultC. lacustris — 0.21 g/L;D. galeata mendotae (48-hr old) — 0.16 g/L; adultDiaptomus oregonensis — –0.12 g/L. No toxicity was observed when these organisms were exposed to a range of concentrations of the emulsifiable concentrate without fenvalerate (the EC blank).Rates of filtration of the¹⁴C-labelled alga,Chlamydomonas reinhardii byD. galeata mendotae, C. lacustris andD. oregonensis were decreased significantly at sublethal concentrations of fenvalerate after only 24-hr exposure.Ceriodaphnia lacustris showed the greatest sensitivity with rates of filtration significantly decreased at 0.01 g fenvalerate/ L. Concentrations of fenvalerate 0.05 g/L resulted in decreased rates of filtration byD. galeata mendotae. A concentration of 0.10 g fenvalerate/ L caused rates of filtration to increase inD. oregonensis. whereas 0.05 and 0.5 g/L resulted in a decrease in these rates.Rates of assimilation of algae byD. galeata mendotae, C. lacustris andD. oregonensis exposed to similar concentrations of fenvalerate were decreased at concentrations 0.05 g fenvalerate/L. Changes in rates of assimilation were not as sensitive a parameter of toxicity as changes in rates of filtration. The EC blank had no significant effects on rates of filtration or assimilation for all three species.     

Assessment of occupational exposure to 4,4′-methylene-bis-(2-chloroaniline) “MOCA” by a new sensitive method for biological monitoring

Summary A new specific and sensitive method for the urinary determination of 4,4-methylene-bis-(2-chloroaniline) (MOCA), a known carcinogen in rats, mice and dogs, has been developed. After a brief study on rats to determine some peculiarities in MOCA urinary excretion, this method was used to assess occupational exposure in French industrial firms. Both the manufacture of MOCA and its use as a curing agent in the production of polyurethane elastomers were surveyed. MOCA excretion levels were distributed from non-detectable (<0.5 g/l) up to 1600 g/l. Concentrations of N-acetyl metabolites, when present, were largely lower than MOCA levels. The results seemed to reflect workers' overall exposure fairly. Preventive measures following analytical determinations often led to an obvious lowering of excretion levels.     

Occupational exposure to hexachlorocyclohexane

Summary In a lindane (-hexachlorocyclohexane =-benzenehexachloride)-producing factory 57 workers were studied with regard to their blood levels of the three hexachlorocyclohexane isomers:-, -, and-HCH. The TLV-TWA (MAK value 1979) for-HCH of 0.5 mg/m³ was not exceeded at any of the workplaces where HCH is synthesized and purified to lindane. Additionally, in some of the workers samples of s.c. adipose tissue were taken for determination of HCH-isomer content. An external group of 20 clerks was examined in the same way for control purposes.In contrast to the control persons, none of whom had HCH-concentrations in serum above the respective detection limits, the values determined in serum of the exposed workers were in the following ranges:-HCH: 10–273 g/l,-HCH: 17–760 g/l, and-HCH: 5-188 g/l. Of special interest is the observation of a significant increase of-HCH-concentration in serum with the time of employment in lindane production, indicating a pronounced accumulation of this substance in the human organism. Concentrations of this isomer in s.c. adipose tissues were about 300-fold higher than in serum. A significant correlation between both parameters could be established.The results of this study show that adherence to the TLV-TWA of-HCH is not sufficient for control of HCH-exposure. Furthermore, biological monitoring of exposed workers is necessary taking into account the three more important isomers-, -, and-HCH.     

Hazardous exposure of ground-living small mammals to cadmium and lead in contaminated terrestrial ecosystems

The dietary exposure to cadmium and lead of two ground-living species of small mammals,i.e., shrewsSorex araneus (Insectivora) and volesMicrotus agrestis (Rodentia), was investigated and related to metal loads in target organs (kidneys and liver). The study was done in two natural areas polluted with cadmium and lead originating from urban and industrial metal sources. The average intake of cadmium by the herbivorous voles varied between 0.1 and 0.4 g/g/day and of lead between 2 and 10 g/g/day. The carnivorous shrews showed a considerably higher metal intake rates,i.e., cadmium 3 to 16 g/g/day and lead 19 to 53 g/g/day, which was largely due to the consumption of contaminated earthworms (Oligochaeta). An average cadmium intake of 15 g/g/day or a lead intake of 20 g/g/day corresponded with critical renal metal loads of 120 g/g for cadmium and 25 g/g for lead, which are indicative of adverse health effects. The renal metal loads in shrews reached the critical level, but they remained far below this level in voles. The results indicate a greater risk of toxic exposure to cadmium and lead in soricine shrews than in microtine rodents.     

Development of a Sublethal Test to Determine the Effects of Copper and Lead on Scleractinian Coral Larvae

A new sublethal toxicity test was developed in this study to measure the effect of copper and lead on the motility of coral larvae. Larval motility was significantly affected by copper and lead doses immediately after dosing. The copper EC₅₀ values for motility of Goniastrea aspera brain coral larvae (12 h, 21 g/L; 24 h, 16 g/L; 48 h, 22 g/L) were much lower than the copper LC₅₀ values for G. aspera larval survival (6 h, 260 g/L, and 24 h, 121 g/L, for 5-day-old larvae and 6 h, 248 g/L, and 24 h, 136.64 g/L, for 6-day-old larvae) during the early part of the experiments. However, at later times, the LC₅₀ values (48 h, 40 g/L, for 5-day-old larvae and 48- h, 87 g/L, for 6-day-old larvae) were similar to the EC₅₀ values for larval motility. The lead 72-h EC₅₀ value for G. aspera larval motility (2900 g/L) was much lower than the lead 72-h LC₅₀ value for larval survival (9890 g/L). The results show that larval motility can be a useful parameter to measure in order to determine the sublethal effects of trace metals on coral larvae.     

Effect of aflatoxin B and rubratoxin B on bacteriophage and rabbit cornea cells

Summary Rabbit cornea cells exhibited a sensitivity to 1 g aflatoxin b₁ and 5 g rubratoxin B per ml of growth medium. No changes were observed in the bacteriophages tested in the presence of 25 g aflatoxin b₁ or 100 g rubratoxin B per ml of medium by the plaque-forming unit method or single-step growth curves.     

Bromacil and diuron herbicides: Toxicity,uptake, and elimination in freshwater fish

Fathead minnows, 30 days old, were exposed to technical grade bromacil and diuron in flow-through tests to determine acute toxicity. LC₅₀ values for bromacil were 185, 183, 182 and 167 mg/L at 24, 48, 96, and 168 hr, respectively; and for diuron, 23.3, 19.9, 14.2, and 7.7 mg/L at 24, 48, 96, and 192 hr, respectively. Eggs, newly hatched fry, and juvenile fish were continuously exposed to lower concentrations of the herbicides for 64 days. Growth was significantly reduced (p 0.01) at the lowest bromacil exposure of 1.0 mg/L. Therefore, it was not possible to determine a no effect concentration. The no effect concentration for diuron was 33.4 g/L, while the lowest concentration which resulted in adverse effects was 78.0 g/L. Adverse effects at 78.0 g/L were an increased incidence of abnormal or dead fry immediately after hatch (p 0.01) and decreased survival throughout the exposure period (p 0.05). Neither herbicide accumulated significantly in fish tissue, as bioconcentration factors were <3.2 and 2.0 for bromacil and diuron, respectively. Rainbow trout (Salmo gairdneri) injected with radiolabeled bromacil or diuron eliminated over 90% of the radioactivity within 24 hr. Parent compound and metabolites were detected in the aquarium water in both cases. Metabolites of diuron recovered from the water included 3,4-dichloroaniline and several demethylated products.     

Lead,cadmium, and aluminum accumulation in the red swamp crayfishProcambarus clarkii G. collected from roadside drainage ditches in louisiana

The concentration of Pb, Cd, and Al in tissues of crayfishProcambarus clarkii were evaluated from several wetland sites located adjacent to roadways and were compared to crayfish harvested from a commercial site free from roadside influences. Abdominal muscle, hepatopancreas, alimentary tract, exoskeleton and blood were analyzed for metal content. Results indicated that levels of contamination obtained in almost all tissues of crayfish from roadside ditches contained significantly higher amounts of metals than those of the commercially harvested control crayfish (p = .05–.001). Detection limits of Pb, Cd, and Al ranged from 0.04 g Pb/g to 16.15 g Pb/g.001 g Cd/g to .13 g Cd/g, and 1.22 g Al/g to 981 g Al/g, respectively. Concentrations of Pb, Cd, and Al were highest in the hepatopancreas and alimentary tract. High levels of these elements were also detected in the exoskeleton. In contrast, muscle tissue was the least affected tissue. Several significant correlations among concentrations of metals were found when comparing a variety of tissues inProcambarus clarkii.     

Internal exposure to organic substances in a municipal waste incinerator

Summary Fifty-three persons occupied in a municipal waste incinerator were examined with respect to their internal exposure to organic substances which may be produced during pyrolysis of organic matter. For this purpose the levels of benzene in blood, polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in plasma, and mono- (MCPs), di- (DCPs), tri- (TCPs), tetra-(TECPs) and pentachlorophenol (PCP) and hydroxypyrene in urine were determined. For control purposes, 431 men and women were examined. Significantly higher values for the workers were found for the excretion of hydroxypyrene [median (m): 0.24vs 0.11 g/l; non-smokers], 2,4/2,5-DCP (m: 10.5 vs 3.9 g/l) and 2,4,5-TCP (m: 1.2 vs 0.8 g/l) and for the HCB level in plasma (m: 4.4 vs 2.8 g/l). For the concentrations of 4-MCP and 2,3,4,6/2,3,5,6-TECP, the controls had significantly higher concentrations in urine than did the workers in the incineration plant (m: 4-MCP 1.7 vs 1.2; 2,3,4,6/2,3,5,6-TECP: 1.2 vs 0.3 g/l). No significant differences between workers and controls were detected with respect to benzene in blood (m: 0.20 vs 0.28 g/l; non-smokers), 2,4,6-TCP and PCPs in urine (m: 0.85 vs 0.60 and 2.2 vs 2.2 g/l) or the levels of PCB congeners in plasma (m: 138, 153, 180: 5.6 vs 4.1 g/l). The elevated levels of hydroxypyrene, 2,4/2,5-DCP, 2,4,5-TCP and HCB in biological material may be related to the incineration of the waste. These elevations, however, are very small and are of interest more from the environmental than from the occupational point of view.