Blood levels exposure index

OSHA has set a standard to keep blood levels in the occupational work force below 40 //g/dL. ACGIH has set a goal relating to a biological exposure index of 50 //g/dL for lead in blood and 150 pjgjdL creatinine for lead in urine. 

Bactericide A pesticide used to control or destroy bacteria Basal diet Ration for adults and starter ration for the young, appropriate to the species it should meet the standard nutritional requirement Base pair mutagens Chemicals or agents that produce a base change in the DNA BEA 2-Bromoethalamine BEI Biological exposure index BLL Blood lead level BEN Balkan endemic nephropathy... 

The concerns aroused by methylmercury in fish, arising from the susceptibility of the developing brain to this neurotoxicant, led to the design and execution of two large prospective studies. One was located in the Seychelle islands, which lie in the Indian Ocean. The other was located in the Faroe Islands, which lie in the North Sea. Both communities consume large quantities of seafood. In the Seychelles, it is almost exclusively in the form of fish. In the Faroes, virtually all the methylmercury comes from the consumption of pilot whales, which are also contaminated with polychlorinated biphenyls (PCBs). Both studies assayed maternal exposures to methylmercury. In the Seychelles, maternal hair was used as the index it reflects the history of blood levels. The Faroes study relied primarily on cord blood. 

BEI Biological Exposure Index a maximum level set by the ACGIH of substance in the blood, exhaled air or urine. 

As DEHP metabolism in human blood is accelerated by blood enzymes, such as esterase, its metabolites are frequently measured. In the study where the metabolites of deuterium-substituted DEHP in urine and in blood serum were compared after oral administration of DEHP, MEHP was found to be the main metabolite in blood serum, existing in greater quantities than MEHHP and MEOHP detected in urine. Therefore, we decided to measure DEHP and MEHP in blood serum. Four healthy volunteers were asked to consume food in containers that were made in part of plastic, and DEHP and MEHP concentrations in blood sera were measured. The concentration of DEHP was equal to or less than the quantitative lower limit (trace level) in all the volunteers. The concentration of MEHP was trace in three of the four volunteers and was lower than the quantitative lower limit in one volunteer. In addition, we measured DEHP and MEHP in human blood plasma samples using LC-MC with the column-switching system as pretreatment. DEHP and MEHP concentrations in blood plasma sampled from six healthy volunteers were equal to or less than the quantitative limit (DEHP <25 ng/ml, MEHP <5 ng/ml). " The results prove that DEHP is rapidly metabolized so that the blood concentration is low and quantification is difficult at normal exposure levels. Urine samples are more suitable for the evaluation of the exposure index of PEs than blood samples. 

Table 1 includes neonatal outcome variables reported to be significantly related to low-level maternal, placental, cord, or very early infancy PbB in one or more studies. Case reports and some older studies that include additional adverse outcomes, usually as a result of high-level exposure (Rom, 1976), have been excluded. To save space. Table I excludes reports of assessed outcome measures not significantly related to PbB in any study in the review. These variables are pre-eclampsia, spontaneous abortion, foetal distress, ponderal index, intrauterine growth retardation, meconium staining, Apgar scores, jaundice, blood type, sex of infant and most scales of the Brazelton Newborn Assessment Scale. 

The relationship of PbB level to systolic and diastolic blood pressure was determined in a study of 89 Boston policemen (race not specified) (Weiss et al. 1986, 1988). These policemen were under observation for health outcomes related to environmental work exposures (i.e., they had traffic exposure histories). After statistically adjusting for previous systolic blood pressure, body mass index, age, and cigarette smoking, high PbB level ( 30 pg/dL) was a significant (p=0.01) predictor of subsequent elevation in systolic blood pressure of 1.5-11 mm Hg in the working policemen with normal blood pressure. Low PbB level (20-29 pg/dL) was not a predictor of subsequent systolic blood pressure elevations. Diastolic pressure was unrelated to PbB levels. 

One of the most sensitive systems affected by lead exposure is the nervous system. Encephalopathy is characterized by symptoms such as coma, seizures, ataxia, apathy, bizarre behavior, and incoordination (CDC 1985). Children are more sensitive to neurological changes. In children, encephalopathy has been associated with PbB levels as low as 70 pg/dL (CDC 1985). The most sensitive peripheral index of neurotoxicity of lead is reported to be slowed conduction in small motor libers of the ulnar nerve in workers with 30-40 pg/dL lead in blood (Landrigan 1989). Other potential biomarkers of lead suggested for neurotoxicity in workers are neurological and behavioral tests, as well as cognitive and visual sensory function tests (Williamson and Teo 1986). However, these tests are not specific to elevated lead exposure... 

The UK Pesticide Safety Directorate (PSD) has decided to use the TEF approach for assessment of combined risk from exposure to mixtures of acetyl cholinesterase inhibitors (organophosphate (OP) compounds and carbamates) (PSD 1999). Despite clear differences in the action of carbamates and OP compounds, the index compounds selected for all acetyl cholinesterase inhibitors were either aldicarb (carbamate) or chlorpyrifos (OP). The POD for determining relative potency was predetermined as the dose level that produced 20% inhibition of red blood cell cholinesterase in a 90-day dietary study in rats. 

Some authors have stated that human hair can be employed as an index for an excess, or a deficiency, of specific nutrients in the diet or as an index of absorption of contaminants from the environment [39]. Analysis of hair is considered to give an indication of the integrated dose of elements ingested by a person over some months. In addition, it is easier to collect hair than blood or urine. Therefore, analysis of human hair is performed by a number of organisations to monitor the level of exposure to heavy metals of a population or an individual [40]. However, this monitoring is often hampered by an insufficient reliability of the measurements. The BCR has thus decided to provide laboratories with a mean of checking their analytical performance by... 

Contaminated Fish Consumption. Serum cholesterol, serum GGT, and blood pressure, but not serum HDL cholesterol or triglycerides, were positively correlated with serum PCB levels in 458 residents of Triana, Alabama (Kreiss et al. 1981). These associations were independent of age, sex, fish consumption, body mass index, and alcohol consumption. Consumption of contaminated fish was the only known source of PCB exposure, but PCB intake was not estimated. DDT was also increased in the serum of the people and in the fish, and serum DDT and serum PCB levels were highly correlated. 

Hair is simple to collect and analyze, but arsenic levels in hair do not respond rapidly to exposure. Blood both is difficult to collect and does not give a consistent or rapid enough response to As exposure of an organism. Thus, even with the attendant collection problems, urine is the most practical index to the exposure of forest workers to the organic arsenical herbicides. Unfortunately, the pharmacokinetics of these herbicides have not been fully developed for dermal exposure, and there are indications that urine is not the sole excretory route. Thus, estimates of exposure based only on As excretion in urine may be only 30% of actual exposure levels (2 8). 

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