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PubMed1978

Correlation of PCB body burden with behavioral toxicology in monkeys.

Eight monkeys fed 2.5 ppm PCB in their daily diet conceived, delivered and nursed five infants, three of which survived past weaning at four months of age. PCB residues in fat in the surviving infants at 8, 10 1/2, and 23 months of age declined linearly when plotted as log concentration versus time (first order clearance), and these functions extrapolated to presumed peak PCB levels of 21, 114, and 123 microgram/g fat (ppm) at 4 months of age. Behavioral tests on these three infants and four normal controls revealed hyperlocomotor activity at 6 and 12 months of age correlated with peak PCB body burdens. Higher peak PCB body burdens also were correlated with increased errors in five of nine learning tasks conducted between 8 and 24 months of age. Point estimates of zero-effect levels of PCB body burdens ranged around 21 ppm, although it was clear that even the monkey carrying only 21 ppm PCBs at four months of age exhibited some behavioral deficits persisting through the final testing at 24 months of age.

Animals↗

PubMed2000

Body burden of aluminum in relation to central nervous system function among metal inert-gas welders.

OBJECTIVES: The relationship between elevated internal aluminum loads and central nervous system function was studied among aluminum welders, and the threshold level for adverse effect was defined. METHODS: For 65 aluminum welders and 25 current mild steel welders body burden was estimated, and the aluminum concentrations in serum (S-Al) and urine (U-Al) were analyzed with graphite furnace atomic absorption spectrometry with Zeeman background correction. Referents and low-exposure and high-exposure groups were defined according to an aggregated measure of aluminum body burden, the group median S-Al levels being 0.08, 0.14, and 0.46 micromol/l, respectively, and the corresponding values for U-Al being 0.4, 1.8, and 7.1 micromol/l. Central nervous system functions were assessed with a neuropsychological test battery, symptom and mood questionnaires, a visual and quantitative analysis of electroencephalography (EEG), and P3 event-related potentials with pitch and duration paradigms. RESULTS: Subjective symptoms showed exposure-related increases in fatigue, mild depression, and memory and concentration problems. Neuropsychological testing revealed a circumscribed effect of aluminum, mainly in tasks demanding complex attention and the processing of information in the working memory system and in the analysis and recall of abstract visual patterns. The visual EEG analysis revealed pathological findings only for aluminum welders. Mild, diffuse abnormalities were found in 17% of the low-exposure group and 27% of the high-exposure group, and mild to moderate epileptiform abnormalities at a frequency of 7% and 17%, respectively. CONCLUSIONS: Both objective neurophysiological and neuropsychological measures and subjective symptomatology indicated mild but unequivocal findings dose-dependently associated with increased aluminum body burden. The study indicates that the body burden threshold for adverse effect approximates an U-Al value of 4-6 micromol/l and an S-Al value of 0.25-0.35 micromol/l among aluminum welders.

Adult↗

PubMed2002

Probabilistic intake assessment and body burden estimation of dioxin-like substances in background conditions and during a short food contamination episode.

The objective was to perform a dioxin body burden estimate based on a probabilistic intake assessment of PCDDs, PCDFs and dioxin-like PCBs because of the so-called 1999 'Belgian dioxin incident'. Monte Carlo simulation techniques were used to combine detailed 7-day food intake data on the individual level from a sample of 14-18-year-old adolescents with 'background' and 'incident-related' food contamination data. In background conditions, 3% of the adolescents had an intake <1 pg TEQ kg(-1) bw day(-1), while 85% had <4 pg TEQ kg(-1) bw day(-1). Milk and other dairy products were the basic source of dioxin-like contaminants, while fish constituted the main source at the higher percentiles of intake. During the dioxin incident, the estimated median dioxin intake showed a moderate increase. At the 99th percentile, the highest intake level, and the 95% upper bound uncertainty level, peak body burden-23.73 ng TEQ kg(-1) bw-remained below body burdens that in the experimental animal or in man are accompanied by a population-based observable increase in the incidence of adverse effects. The 1999 Belgian dioxin incident most likely did not affect public health in Belgium in a measurable way, although exceptions remain possible on the individual level.

Adolescent↗

PubMed1978

Lead and cadmium in hair as an indicator of body burden in rats of different age.

The purpose of this work was to evaluate whether hair values of lead and cadmium can be used as an indicator of the body burden of these metals in different age groups. The experiments were performed on rats aged 2 and 18 weeks, which received 203Pb and 115mCd by intraperitoneal injection. The whole body retention and the retention of these radioisotopes in the hair (including the skin) was determined 7 days later. Younger animals showed a higher retention in the whole body and hair of radioactive lead and cadmium. The hair values when expressed as the percentage of the whole body retention were for 203Pb the same in young and adult rats but for 115mCd they were 2 to 3 times higher in young animals than in adults. It is concluded that lead hair values are a good indicator of the total body burden in both age groups. However, the cadmium body burden of young animals would be greatly overestimated if based on hair values only. This findings might be relevant for interpreting results of hair concentrations of lead and cadmium in children.

Aging↗

PubMed1995

Short term fasting does not aggravate immunosuppression in harbour seals (Phoca vitulina) with high body burdens of organochlorines.

Two groups of 11 harbour seals (Phoca vitulina) with different body burdens of organochlorines were subjected to an experimental 15-day fasting period, during which they lost an average 16.5% of their body weights. Blood levels of the most persistent organochlorines showed an approximate twofold increase, while levels of aryl hydrocarbon receptor-binding organochlorines remained largely unaffected. Few differences in immunological parameters were observed between the two dietary groups. Numbers of circulating lymphocytes dropped to about 65% of the initial values and NK cell activity showed a slight increase in both groups. Mitogen- and antigen-induced lymphoproliferative responses of the Baltic group of seals remained within normal ranges. These results suggest that relatively short-term fasting periods do not present an additional immunotoxicological risk to seals with high body burdens of organochlorines.

Adipose Tissue↗

PubMed1986

Estimation of mercury body burden from dental amalgam: computer stimulation of a metabolic compartmental model.

Estimated release rates of Hg vapor from dental amalgams permitted calculation of the potential Hg body burden by employing a four-compartment model for inorganic and elemental Hg distribution. A computer program, compatible with most personal computers, simulated the cumulative and incremental distribution in each compartment and total body accumulation between 1 and 10,000 days for different daily Hg dosages. For a given Hg dose of 30 micrograms/day, metabolic compartments R1-R3 were close to equilibrium at 5, 100, and 300 days, respectively; whereas by 10,000 days, R4 closely approximated total body burden and had not yet attained equilibrium. Projected values obtained with the computer model were consistent with results obtained by another method using a standard tissue burden equation, which employed experimentally determined tissue half-lives for blood and CNS. The model predicted that continuous exposure to elemental Hg vapor, at 30 micrograms/day for 10 years, would result in a total Hg body burden of 5.9 mg, of which 4.8 mg could be contained in R4. Assuming that the Hg in R4 displayed uniform distribution throughout the body, then the brain concentration was estimated to be 68 ng/g wet weight. In contrast, if Hg in R4 reflected long-term preferential accumulation in brain and other neural tissue, then concentrations as high as 4.0 micrograms/g could be attained. However, predictions of Hg concentrations in blood and urine were well within established ranges, and were unlikely to be of utility in assessing effects of chronic low-dose Hg exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Burden↗

PubMed2001

Dioxin body burdens in operation ranch hand veterans: promotion blocking and cancer causation.

The cancer incidence data from the Operation Ranch Hand Study are plotted as a function of seven dioxin body burden classifications from zero through modest levels above background. The three significant cancer incidence peaks and three significant cancer incident troughs observed are used to test a model which specifies dioxin activity as both a promoter blocker and a cancer causation agent. There is a significant, 50% reduction in total cancers other than skin at the highest dioxin body burden level compared to background. There is a significant reduction in prostate cancers in Black veterans, but not in White, as a function of increasing dioxin body burden.

Adult↗

PubMed1989

Epidemiologic study on the association between body burden mercury level and idiopathic Parkinson's disease.

A case-control study was conducted among the multiethnic population of Singapore to test the hypothesis that a high level of body burden mercury is associated with an increased risk of Parkinson's disease (PD). Selected factors investigated that could contribute to the body burden of mercury included dietary fish intake, ethnic over-the-counter medications, occupational exposures and possession of dental amalgam fillings. Detailed interviews were completed in 54 cases of idiopathic PD and 95 hospital-based controls, matched for age, sex and ethnicity, between July 1985 and July 1987. After adjusting for potential confounding factors, including dietary fish intake, medications, smoking and alcohol consumption, there was clear monotonic dose-response association between PD and blood mercury levels. The odds ratios (OR) and 95% confidence intervals (CI) for the approximate subject tertiles based upon blood mercury levels were 8.5 (CI = 2.2-33.2) and 9.4 (CI = 2.5-35.9), relative to the tertile with lowest blood mercury levels (less than 5.8 ng Hg/ml). Similar associations were revealed using scalp hair and urinary mercury levels. However, only the comparisons between the highest and lowest tertiles were statistically different from unity (p less than 0.05). When the body burden mercury indicators were mutually adjusted in addition to the four confounding factors, blood and urinary mercury levels showed ORs of 21.00 and 18.65, respectively. These ORs were statistically different from unity (p less than 0.05, 2-sided test). After adjustment, scalp hair mercury was shown to be a poor predictor of PD risk.

Adult↗

PubMed2006

Non-invasive therapy to reduce the body burden of aluminium in Alzheimer's disease.

There are unexplained links between human exposure to aluminium and the incidence, progression and aetiology of Alzheimer's disease. The null hypothesis which underlies any link is that there would be no Alzheimer's disease in the effective absence of a body burden of aluminium. To test this the latter would have to be reduced to and retained at a level that was commensurate with an Alzheimer's disease-free population. In the absence of recent human interference in the biogeochemical cycle of aluminium the reaction of silicic acid with aluminium has acted as a geochemical control of the biological availability of aluminium. This same mechanism might now be applied to both the removal of aluminium from the body and the reduced entry of aluminium into the body while ensuring that essential metals, such as iron, are unaffected. Based upon the premise that urinary aluminium is the best non-invasive estimate of body burden of aluminium patients with Alzheimer's disease were asked to drink 1.5 L of a silicic acid-rich mineral water each day for five days and, by comparison of their urinary excretion of aluminium pre-and post this simple procedure, the influence upon their body burden of aluminium was determined. Drinking the mineral water increased significantly (P<0.001) their urinary excretion of silicic acid (34.3 +/- 15.2 to 55.7 +/- 14.2 micromol/mmol creatinine) and concomitantly reduced significantly P=0.037) their urinary excretion of aluminium (86.0 +/- 24.3 to 62.2 +/- 23.2 nmol/mmol creatinine). The latter was achieved without any significant (P>0.05) influence upon the urinary excretion of iron (20.7 +/- 9.5 to 21.7 +/- 13.8 nmol/mmol creatinine). The reduction in urinary aluminium supported the future longer-term use of silicic acid as non-invasive therapy for reducing the body burden of aluminium in Alzheimer's disease.

Aged↗

PubMed1981

Hair cadmium content: is it a biological indicator of the body burden of cadmium for the occupationally exposed worker?

The primary objective of this study was to evaluate the cadmium (Cd) levels measured in scalp hair as a potential predictive index of the body burden of Cd. In vivo measurements of kidney and liver Cd along with hair, blood, and urine Cd levels were obtained in 29 industrially-exposed workers and ten control subjects. The relationship of hair Cd levels to the Cd values for the kidney, liver, blood, and urine were tested using nonparametric analyses. In the control group no statistically significant correlations were found. In the Cd-exposed workers with more than one year of employment there were weak correlations (p approximately equal to 0.05); however, the relationships were not sufficiently quantitative for predicting the status of an individual worker. Furthermore, when workers with less than one year of exposure were included in the analysis, no significant correlations were obtained. Although this latter group of workers had low body burdens of Cd, exceptionally high Cd concentrations were found in their hair--an observation that was unexpected. It was concluded that hair Cd levels are not a good index of body burden of Cd in the industrially-exposed individual.

Adult↗

PubMed1999

Metabolism and body-burden of PCBs in lactating dairy cows.

This paper uses data from a detailed 4 month PCB mass balance study on lactating cows fed a naturally contaminated background diet to quantify the metabolism and body-burdens of a range of PCB congeners. Dietary intake fluxes and milk and faecal output fluxes reported previously are combined with subcutaneous fat and blood PCB concentrations and with data from tissue/organ samples from a slaughtered animal to estimate the degree of metabolism within the cow. A total body burden is derived, showing that fat deposits account for approximately 98% of total PCB present in the lactating cow. The daily intake through feed (ng day-1) accounted for between 0.9 and 1.5% of the total body burden for persistent congeners (e.g. PCB 153) and up to 43% for those congeners which are readily metabolised (e.g. PCB 52). Detailed balances for a range of tri- to octa-chlorinated PCBs are presented and clearly demonstrate that many congeners are metabolised effectively by lactating dairy cows (e.g. PCB 149) whilst others are efficiently transferred to human dairy food products. An approach to predicting the degree of metabolism for individual PCB congeners is presented which gives good agreement with observations.

Animals↗

PubMed2006

Body burden of dioxins and dioxin-like polychlorinated biphenyls in pregnant women residing in a contaminated area.

A large pentachlorophenol (PCP)-manufacturing plant located in southwestern Taiwan operated between 1965 and 1982. The present study was conducted to ascertain whether an increased body burden of dioxins existed in pregnant women living in an area of Tainan city contaminated by chemicals from this plant. Twenty-eight pregnant subjects, 21-39 years of age and residing in the study area between March and December of 2004 with a mean dwelling time of 6.07+/-6.11 years, were recruited. Concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (PCBs) in serum of recruited residents were determined. Pregnant women residing in the study area >3 years had significantly higher PCDD (7.48 versus 5.13 pg-toxic equivalents [TEQ]/g-lipid) and dioxin-like PCB (6.70 versus 3.74 pg-TEQ/g-lipid) values as compared to those residing < or = 3 years. Furthermore, dioxin concentrations increased with increasing dwelling time. Statistical analyses performed according to demographic characteristics and socioeconomic and dietary habits revealed that total TEQ values were significantly associated with fish consumption and smoking status. Dioxin congeners with greater degrees of chlorine substitution (e.g., HpCDD/F and OCDD/F) partitioned to greater degrees in the subjects of this study as compared to subjects in the general Taiwanese population. The findings of this study strongly implicate the activity of the PCP manufacturing plant in the observed increase in dioxin body burden. Investigation of the health consequences of this increased body burden is recommended.

Adult↗

PubMed2003

Effects of aqueous and dietary preexposure and resulting body burden on silver biokinetics in the green mussel Perma viridis.

To determine whether preexposure of green mussel Perna viridis to Ag influenced metal uptake kinetics we compared various physiological indicators of metal uptake kinetics between the control mussels and mussels preexposed to Ag in both diet and water at different levels (up to 5 weeks). In all preexposed mussels, the assimilation of Ag increased by 1.1-3.0 times with increasing Ag body concentration (0.651-19.3 microg g(-1)) as compared with the controls (Ag body concentration of 0.311-0.479 microg g(-1)), whereas the efflux rate constants decreased by 45-88%. There was no significant increase in Ag associated with the metallothionein-like protein (MTLP) fraction following exposure of the mussels to Ag through either the dissolved or food phase. The clearance rates were little affected or depressed byAg preexposure, and the relationship between the Ag influx rate from the dissolved phase and the Ag preexposure was somewhat complicated. The influx rate decreased with increasing Ag body burden at <2.5 microg g(-1), above which it increased with increasing Ag body burden. Our results indicate that the mussels may modify physiological processes to ambient chronic Ag exposure, consequently accumulating more Ag. Ag body concentration in these mussels may therefore increase disproportionally in response to increasing Ag concentration in the ambient environments. Ag preexposure and resulting body burden should be considered carefully when interpreting the observed Ag concentration in biomonitoring animals to evaluate the Ag pollution in seawater.

Animals↗

PubMedDate not supplied

Estimation of the body burden of arsenic in a child fatally poisoned by arsenite weedkiller.

A three-year-old child died after ingestion of a mouthful of an estimated 44% sodium arsenite solution. Litigation was initiated based on the quality of emergency treatment at a rural hospital. An issue raised in litigation was whether the child could have survived if he had received an additional dose of BAL (dimercaprol). BAL had been sent for from a neighboring city and arrived approximately 2.0 h after admission. The first 50-mg dose of BAL could have combined with a maximum of 30 mg arsenic; a second dose could have brought the total of chelated arsenic to 60 mg. To determine the total body burden of arsenic in the child, multiple tissues were analyzed. The total body burden was estimated at 113 mg, with 100 mg of this total attributable to the ingested solution. The actual body burden after two doses of BAL therefore would have been at least 40 mg, a fatal level.

Arsenic↗

PubMed1999

Urinary excretion measurements for the assessment of body burden of radiocaesium in man: differences between potassium and creatinine normalisation.

Relationships between 24-h urinary excretion and body burden of 137Cs obtained in a south-Swedish population, together with data from the literature, were applied to urine samples collected in 1994-95 from adult subjects living in Russia, in order to estimate their average body burden of 137Cs. Estimates obtained through creatinine normalisation of the 137Cs content in the Russian urine were a factor of 2 higher than estimates obtained through potassium normalisation. The accuracy of both these normalisation methods is discussed, as well as the influence of the difference in dietary habits between the two populations.

Adult↗

PubMedDate not supplied

Termite control and other determinants of high body burdens of cyclodiene insecticides.

Breast milk fat concentrations of three cyclodiene insecticides--dieldrin, heptachlor epoxide, and oxychlordane--were measured in 797 primiparous women, and sources of exposure that contributed significantly to high body burdens were investigated. All three distributions were highly skewed to the right, with median concentrations falling between 0.007 and 0.039 mg/kg. Termite control of residence was associated consistently with being in the high-body-burden group for all three compounds, but the association was greatest for heptachlor. Age, socioeconomic status, residential area, smoking, and home use of insecticides were also associated with high body burden of one or more of the compounds, but the odds ratios were lower than those for termite control; the findings were inconsistent for the three compounds. The results for termite control remained statistically significant when we adjusted for the other factors; therefore, termite control of residence is an important risk factor for cyclodiene insecticide absorption.

Adipose Tissue↗

PubMed1996

Decrease in milk and blood dioxin levels over two years in a mother nursing twins: estimates of decreased maternal and increased infant dioxin body burden from nursing.

This study addresses the issue of breast-feeding and its reduction of maternal dioxin body burden. Nursing is also a source of infant dioxin exposure. This study extends our previous efforts to investigate a nursing mother's milk and blood dioxin levels. We report polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) dioxin toxic equivalents (TEQs) in milk (M) and blood (B) both before and also after two years of nursing twins to be 16.9 ppt (M), 14.9 ppt (B), and 3.1 ppt (M) and 4.9 ppt (B), respectively. The ratios of measured congeners comparing milk to whole blood from a nursing mother taken initially and after two years of nursing vary from 0.36 to 8.40 in 1992 and 0.17 to 1.0 in 1994. The mother's body burden was initially calculated to be 329 ng TEQ from milk levels and 291 ng TEQ from blood levels using samples taken in February 1992 and decreased to 60.1 ng TEQ from milk and 96 ng TEQ from measured blood using samples collected in December 1994. We calculate that the excretion of dioxin TEQ by the mother through breast-feeding is 269 ng TEQ, which is similar to the 303 ng TEQ estimated total dioxin intake by the twins over two years. The average daily dioxin intake from nursing is 66 pg TEQ/kg-BW/day for each twin over the two years.

Benzofurans↗

PubMed1995

Modeling response of species to microcontaminants: comparative ecotoxicology by (sub)lethal body burdens as a function of species size and partition ratio of chemicals.

A model was designed and calibrated with accumulation data to calculate the internal concentrations of microcontaminants in organisms as a function of a few constants and variables. The main factors are the exposure time, the external exposure concentration, the partition ratio of the compound, and the size of the taxon concerned. The model was applied to calculate the lethal and sublethal body burdens of several priority compounds and some major taxa. Estimations were generally confirmed at the order of magnitude level by measured residues and applied doses if available. According to the estimations, most priority compounds chosen were critical for most taxa above internal concentrations of 0.1 mmol.kg-1 wet wt. Trichloromethane, 1,2,4-trichlorobenzene, and hexachlorobenzene were lethal above this level only, whereas other organic microcontaminants affected at least some taxa at lower body burdens. The log(Kow) of the organic compounds ranged from 2.0 to 7.0. Keeping in mind that bioconcentration and -magnification ratios for metals may be quite variable, the lowest critical residues estimated were just below the value of 0.1 mmol.kg-1 wet wt. Here, external concentrations encountered in natural habitats seem to be a promising tool for predictive comparative ecotoxicology. The critical body burdens for plants and invertebrates may have been overestimated due to uncertainty about the parameters. Among the different taxa, however, the fish families chosen (Salmonidae and Cyprinidae) seem to be most sensitive to most compounds. Internal response concentrations of the herbicide atrazine were the lowest in micro- and macrophytes, whereas parathion affected invertebrates at low levels. The database that provided the external response concentrations was also consulted to estimate so-called extrapolation or safety factors. On average, long-term no effect concentrations in water are estimated to be about 10-30 times below short-term median lethal levels. In general, short-term versus long-term, lethal versus sublethal, and median versus no response concentration ratios each contributed factors of about 2-3 to this overall ratio. The model for internal concentrations indicated that the ratio between the short-term and the long-term LC50 will be high for large species and high octanol-water partition ratios.

1-Octanol↗