Hand Exposures Research Articles

Five weeks of intermittent hand exposures to alternating cold and hot stimuli do not modify finger cold-induced vasodilatation response.

We tested the hypothesis that prolonged intermittent hand exposures to transient contrast thermal stimuli would enhance the finger cold-induced vasodilatation (CIVD) response during localized cooling. Eight healthy men participated in a 5-week regimen, during which they immersed, thrice per week, the non-dominant (EXP) hand in 8° and 43°C water, sequentially and at 3-min intervals, for a total period of 60min. The contralateral (i.e., dominant) hand served as the control (CON) hand. Before and after the regimen, subjects conducted two 30-min hand cold (8°C water) provocation trials, one with the EXP hand and the other with the CON hand. In addition, a flow-mediated dilatation test was performed in the brachial artery of the EXP arm. Regardless of the hand tested, the average finger skin temperature [CON hand: pre-trial=10.5 (1.2)°C, post-trial=10.8 (1.3)°C and EXP hand: pre-trial=10.7 (1.1)°C, post-trial 10.9 (1.1)°C; p=0.79], and the incidence of CIVD events [CON hand: pre-trial=1.1 (1.2) events, post-trial=1.2 (1.1) events and EXP hand: pre-trial=1.1 (0.8) events, post-trial=1.1 (0.8) events; p=0.88] were not affected by the 5-week regimen. The sensation of cold-induced pain was transiently alleviated following the regimen (p=0.02). The flow-mediated dilatation response of the EXP brachial artery remained unaltered [pre-trial=5.4 (3.2)%, post-trial=4.7 (3.6)%; p=0.51]. Therefore, five weeks of intermittent hand exposures to alternating cold and hot stimuli do not improve finger temperature responsiveness to sustained localized cold.

Carpal tunnel syndrome and occupational hand exposures: a Danish nationwide cohort study

ObjectivesThe aim was to examine exposure–response relations between occupational hand exposures and carpal tunnel syndrome (CTS) and to compare the relation between surgery-treated and non-surgery-treated CTS. The secondary aim was...

Personal noise exposure during daily commutes and subjectively reported stress: A trip stage level analysis of MobiliSense data

BackgroundThe auditory and non-auditory health effects of noise have long been established in the literature but previous studies have mainly been in the context of occupational risk. Recent research suggests that daily noise exposures occurring during social activities and commute may be associated with higher psychological stress. Our aim was to explore the association between modes of transportation and noise on the one hand and noise exposures and reported stress on the other hand. Although existing literature shows that noise exposure is especially high during commutes, studies on the topic have been sparse due to cost and logistic constraints; furthermore, sample sizes have been small. MethodsThe present study uses data collected on the daily commutes of 253 participants of the Mobilisense cohort study between 2018 and 2020. Personal dosimeters were used to measure noise exposure by frequency bands over a period of 4 days, resulting in a sample of 7800 trip stage windows. Participants reported trip stress levels during an a posteriori phone mobility survey on a scale from 1 (no stress) to 7 (significantly stressful conditions). Modes of transportation (metro, car, walking, etc.) were collected from the same mobility survey based on Global Positioning System (GPS) receivers. ResultsWhile all transport modes resulted in higher exposure to low frequency noise compared to walking, all modes but tramway and driving or being the passenger of a car were associated with an increased exposure to high frequency noise. The LAeq noise indicator (overall noise) was associated with reported stress: for every 10 dB(A) increase in LAeq, individuals reported experiencing 1.118 times (95% confidence interval: 1.067, 1.172) higher levels of stress. Multiple noise indicator models did not show evidence that specific frequency components were associated with stress beyond overall noise. ConclusionOur findings suggest that noise exposure during commutes vary according to modes of transportation. Given that noise exposure resulted in higher reported levels of stress, future research should examine transportation noise effects on physiological variables.

Electronic Cigarette Usage Patterns and Perceptions in Adult Australians.

Despite their increasing popularity, and Australia's unique regulatory environment, how and why Australian adults use e-cigarettes and their perceptions of their safety, efficacy and regulation have not been extensively reported before. In this study, we screened 2217 adult Australians with the aim of assessing these questions in a sample of current or former e-cigarette users. A total of 505 out of 2217 respondents were current or former e-cigarette users, with only these respondents completing the full survey. Key findings of this survey included the high proportion of respondents who indicated they were currently using e-cigarettes (307 out of 2217 = 13.8%), and the high proportion of current e-cigarette users that were also smokers (74.6%). The majority of respondents used e-liquids containing nicotine (70.3%), despite it being illegal in Australia without a prescription, and the majority bought their devices and liquids in Australia (65.7%). Respondents reported using e-cigarettes in a variety of places, including inside the home, inside public places (where it is illegal to smoke tobacco cigarettes), and around other people-which has implications for second and third hand exposures. A significant proportion of current e-cigarette users (30.6%) thought that e-cigarettes were completely safe to use long-term, although in general, there was a large amount of uncertainty/ambivalence with respect to perceptions of e-cigarette safety and efficacy as smoking cessation tools. This study shows that e-cigarette use is common in Australia, and that appropriate dissemination of unbiased research findings on their safety and efficacy in smoking cessation is urgently required.

Radiation exposure to allied health personnel handling blood specimens from patients receiving radioactive iodine-131 and recombinant human TSH (thyrogen®) stimulation

With increasing use of recombinant human TSH (rhTSH) stimulation protocol in radioactive iodine-131 treatment of thyroidectomised differentiated thyroid carcinoma (DTC), there is increasing concern regarding radiation safety during collection and processing of radioactive blood samples. Our study aims to quantify this radiation exposure in the context of current radiation guidelines to provide a practical safety framework. We analysed 45 patients prospectively referred to a tertiary centre in Singapore, who had histologically proven DTC, and who were thyroidectomised and planned for I-131 with rhTSH stimulation. Each patient received rhTSH for two consecutive days, with I-131 administered 24 h after, and a stimulated Thyroglobulin blood sample collected and processed 72 h after the last rhTSH dose. We measured radiation exposures with dosimeters. Based on the average and maximum exposure rates calculated, we extrapolated and derived the number of radioactive blood samples that could be safely collected and processed. Mean hand and body radiation exposures during venepuncture and blood processing were generally significantly higher than background radiation. Based on average exposure rates, the permissible number of blood samples that can be collected and processed is 9.09 × 103 per year (24 per day) and 8.70 × 104 per year (238 per day), respectively. This is the first study to date to extrapolate permissible thresholds that can serve as a practical guideline to the number of radioactive blood samples which can be safely collected and processed, following radioactive iodine therapy, within the limits of current radiation guidelines. Once validated, generalisations to other radioactive therapies may be considered.

A Red, Swollen Finger

A 75-year-old man with atrial fibrillation taking amiodarone and apixaban, heart failure with an ejection fraction of 20%, and long QT interval presented for evaluation of progressive swelling and erythema of the right fifth finger over 5 months. He had no known trauma to the hand or unusual exposures. He owned a cat and enjoyed the outdoors. On examination, he had a small nodular papule on the right fifth digit with surrounding fusiform swelling and erythema (Figure 1). The left hand was unaffected.

A COMPARISON OF CONTEMPORARY PORTABLE X-RAY SYSTEMS

<h3>Background</h3> There is substantial evidence for a cumulative dose-related response to ionizing radiation in the form of cancer development years after initial exposure. Therefore, this study focused on effective dose (E), a quantity with direct correlations to biologic risk from dental x-ray exposures. <h3>Objectives</h3> The purpose of this study was to measure doses and calculate (E) from adult full-mouth examinations (FMXs) by using handheld and conventional wall-mounted x-ray sources with both circular and rectangular collimation (RC). <h3>Materials and Methods</h3> A human tissue-equivalent phantom and optically stimulated luminescent dosimeters were used to measure dose from simulated FMXs (n = 18) at 24 head/neck tissue sites. The parameters were 70 kV/7 mA (0.84 mAs and 1.34 mAs) for Conventional Circular and RC handheld device; 60 kV/2.5 mA (2.16 mAs) for NOMAD Circular and RC handheld device; and 60 kV/2.0 mA (1.98 mAs) for Xray2 Go Circular (XTG) handheld device. Analysis of variance (ANOVA) and Tukey's HSD ("honest significant difference") statistics demonstrated significant relationships. <h3>Results</h3> The FMX E (µSv) values were: NOMAD RC (6.9); XTG (16.7); NOMAD Circular (17.4); and Conventional Circular (26.3). For circular techniques, the handheld device E was significantly lower than the conventional unit for both devices (<i>P</i> < .0001). With RC, E was significantly lower than all circular techniques (<i>P</i> < .0001). Significant differences in E were found for all modality combinations except NOMAD Circular and XTG (<i>P</i> = .8329). Operator groin exposure was significantly higher (60%–90%) than thyroid, chest, and trigger hand exposures, which were indistinguishable from ambient background levels, for all handheld modalities (<i>P</i> < .0001). <h3>Discussion</h3> Handheld device E was at least 34% less than conventional circular and as much as 74% less with the use of RC. Operator exposure to the groin can increase significantly from overangulating the handheld sources; however, the addition of RC can reduce this exposure by as much as 76%.

Air, hand wipe, and surface wipe sampling for Bisphenol A (BPA) among workers in industries that manufacture and use BPA in the United States

ABSTRACTFor decades, bisphenol A (BPA) has been used in making polycarbonate, epoxy, and phenolic resins and certain investment casting waxes, yet published exposure data are lacking for U.S. manufacturing workers.In 2013–2014, BPA air and hand exposures were quantified for 78 workers at six U.S. companies making BPA or BPA-based products. Exposure measures included an inhalable-fraction personal air sample on each of two consecutive work days (n = 146), pre- and end-shift hand wipe samples on the second day (n = 74 each), and surface wipe samples (n = 88). Potential determinants of BPA air and end-shift hand exposures (after natural log transformation) were assessed in univariate and multiple regression mixed models.The geometric mean (GM) BPA air concentration was 4.0 µg/m3 (maximum 920 µg/m3). The end-shift GM BPA hand level (26 µg/sample) was 10-times higher than the pre-shift level (2.6 µg/sample). BPA air and hand exposures differed significantly by industry and job. BPA air concentrations and end-shift hand levels were highest in the BPA-filled wax manufacturing/reclaim industry (GMAir = 48 µg/m3, GMHand-End = 130 µg/sample) and in the job of working with molten BPA-filled wax (GMAir = 43 µg/m3, GMHand-End = 180 µg/sample), and lowest in the phenolic resins industry (GMAir = 0.85 µg/m3, GMHand-End = 0.43 µg/sample) and in the job of flaking phenolic resins (GMAIR = 0.62 µg/m3, GMHand-End = 0.38 µg/sample). Determinants of increased BPA air concentration were industry, handling BPA containers, spilling BPA, and spending ≥50% of the shift in production areas; increasing age was associated with lower air concentrations. BPA hand exposure determinants were influenced by high values for two workers; for all other workers, tasks involving contact with BPA-containing materials and spending ≥50% of the shift in production areas were associated with increased BPA hand levels. Surface wipe BPA levels were significantly lower in eating/office areas (GM = 9.3 µg/100 cm2) than in production areas (GM = 140 µg/100 cm2).In conclusion, worker BPA exposure was associated with tasks and conditions affecting both inhalation and dermal exposure. The potential for BPA-related health effects among these workers is unknown.

Gafchromic XR-QA2 film as a complementary dosimeter for hand-monitoring in CTF-guided biopsies.

Computed tomography fluoroscopy (CTF) is a useful imaging technique to guide biopsies, particularly lung biopsies, but it also has the potential for very high hand exposures, despite use of quick‐check method and needle holders whenever feasible. Therefore, reliable monitoring is crucial to ensure the safe use of CTF. This is a challenge, because ring dosimeters monitor exposure only at the base of one finger, while the fingertips may be exposed to the highly collimated CT beam. In this work we have explored the possibility of using Gafchromic XR‐QA2 self‐developing film as a complementary dosimeter to quantify hand exposure during CTF‐guided biopsies. A glove used in a previous study and designed to contain 11 TLDs was adapted to include Gafchromic strips 7 mm wide, covering the fingers. A total of 22 biopsies were successfully performed wearing this GafTLD glove under sterile gloves, and the IR reported no difficulty or reduction of dexterity while wearing it. Comparison of dose distributions obtained from digitization of the Gafchromic film strips and absolute Hp(0.07) readings from TLDs showed good agreement, despite some positional uncertainty due to relative movement. Per procedure, doses at the base of the ring finger can be as low as 3%–8% of hand dose maximum. Accumulated dose at the base of the ring finger was four times lower than the dose maximum.PACS numbers: 07.57.Kp, 29.40.‐n, 85.25.Pb, 87.57.qp

The Importance of Hand Exposures to Absorbed Dosage of Hand Harvesters

Fruit harvesters’ primary pesticide exposure results from direct dermal and clothing contact with foliar residues. The transfer of pesticide residues from foliage to strawberry harvesters’ hands and their subsequent dissipation under normal occupational conditions in the field was examined. The effectiveness of latex gloves as sampling dosimeters was evaluated and compared with bare-handed harvester exposures. After application of malathion and fenpropathrin insecticides on strawberry fields, resulting harvester exposures using four independent methods were studied. Between d 4 (preharvest interval, PHI) and d 7 after pesticide application, (1) dislodgeable foliar residues, (2) pesticide residues accumulating on the gloves, and (3) end-of-shift harvester hand-wash residues decreased by 90, 75, and 85%, respectively. In contrast, the 7-d decline in excreted urine metabolites was only 43% for gloved harvesters and 29% for barehanded ones. In addition, gloved harvesters displayed 23% lower biomonitored exposures than barehanded ones, demonstrating that latex gloves are an effective protective barrier against surface residues. Since malathion and its metabolites are readily excreted, data indicated that there were likely other sources of excreted malathion breakdown products present on foliar surfaces after dissipation of malathion itself.

Chemical emissions from e-cigarettes: Direct and indirect (passive) exposures

E-cigarettes are marketed as an alternative to smoking tobacco that only produces harmless water vapor, with no adverse impact on indoor air quality. Recent measurements of the chemical emissions from e-cigarettes indicate the following chemicals are inhaled by users and exhaled into the environment where second hand exposures occur; glycols, formaldehyde, nitrosamines, nicotine, and flavorants. For the direct exposure of e-cigarette users, the hazard quotients were exceeded for 7 of the 9 chemicals assessed, while for the indirect (passive) exposure to non-users, the hazard quotient was exceeded for 2 of the 9 chemicals (i.e., propylene glycol and nicotine). The analytical methods for assessing the emissions of formaldehyde and nicotine from e-cigarettes may be providing emission rates that are less than the true emission rates. We conclude that e-cigarettes emit many harmful chemicals into the air and need to be regulated in the same manner as for tobacco smoking. Manufacturers of e-cigarettes have a responsibility to evaluate the safety of their products before offering them for sale (e.g., the precautionary principle), including the health impacts caused by the emissions of formaldehyde, flavorants, and the glycol carrier oils.

Dermal exposure from transfer of lubricants and fuels by consumers.

Consumer uses of fuels and lubricants in Europe are subject to the Registration, Evaluation, Authorization and restriction of CHemicals (REACH) legislation. Ten volunteers completed a series of exposure situations to simulate filling a vehicle fuel tank with diesel (ES1 Diesel), adding lubricant to a car engine (two situations, one filling point easier to reach (ES2 Easy) than the other (ES3 Hard)) and lubricating a bicycle chain (ES4 Bike). Dermal exposure to the hands and forearms was assessed using a wipe sampling method. A high proportion of samples was less than the limit of detection (ES1=38%, ES3=60%, ES2 and 4, both 78%). In ES1 Diesel, dermal exposure to the hands and forearms ranged from <0.25 μg/cm(2) to 96.21 μg/cm(2). Significantly higher dermal exposure was observed when a lower level of care was taken to complete the task. In ES2 Easy and ES3 Hard, the hand and forearm results ranged from <0.1 μg/cm(2) to 3.33 μg/cm(2) and from <0.1 μg/cm(2) to 3.54 μg/cm(2), respectively. In ES4 Bike, the hand and forearm exposures ranged from <0.35 μg/cm(2) to 5.25 μg/cm(2). Not all volunteers fully complied with the ES4 instructions, thus highlighting that this situation may have more variability in consumer behaviour. The ratio of the amount measured on the hands and forearms to the amount of product handled for ES1 Diesel, ES2 Easy and ES3 Hard was less than 0.0001%, for ES4 Bike it was 0.04%. Mixed effect models showed that the between and within volunteer variations are small for all except ES1 Diesel, where the within volunteer variation was relatively large (likely due to the few high measurements). This study reports dermal exposure measurement data, which will be of value when updating REACH and other exposure assessments for these, and similar, petroleum products.

Abstract 1278: Obesity enhances benzo(a)pyrene-induced colon tumorigenesis in a PIRC rat model of colon cancer..

Abstract Colorectal cancer is a contributing factor for significant mortalities in the United States, with 50,000 deaths per year and around 140,000 new cases expected to be diagnosed in this year. Epidemiological studies have pointed out that obese people have a higher risk for colon cancer. It is well known that overweight or obesity is induced by excess energy intake from dietary fat. Additionally, consumption of well-done red meat and saturated fats, rich in food-borne environmental toxicants such as polycyclic aromatic hydrocarbons (PAHs) has also been implicated as one of the causative factors for sporadic colon cancer. Thus, on one hand, diet-induced obesity and on the other hand exposures to environmental carcinogens contribute to the development of colon cancer. Therefore, the objective of this study was to investigate whether the colon polyp burden was accelerated by diet-induced obesity when exposed to environmental carcinogens.To test this concept, we have employed an adult male transgenic rat model, the Polyposis In the Rat Colon (PIRC) kindred type. This rat is a mutagen-induced nonsense allele of the rat Apc gene on an inbred F344/NTac (F344) genetic background. This rat model is advantageous because of its longer life span and lack of the tumor suppressor gene Apc. We have explored whether tumor burden in PIRC male rat (PIRC-M Heterozygous F344/NTac-Apcam1137) was influenced by the ingestion of different types of fat containing benzo(a)pyrene [B(a)P], a prototypical PAH compound. Treatment consisted of 25 and 50 μg B(a)P/kg body wt., dissolved in tricaprylin, administered to 7-week-old male PIRC rat daily via oral gavage for 60 days. One group of rats received the AIN-76A control diet and the other group, the Western diet throughout the duration of this study. At the end of exposure, rats were sacrificed; colons were retrieved and preserved in 10% formalin for observation of gross pathological changes. An increased prevalence of adenomas in colon of rats that were maintained on Western diet compared to AIN-76A diet and controls (P &amp;lt; 0.05) was noticed. Interestingly, we have also observed adenomas with high grade dysplasia in B(a)P + Western diet group and these incidences were of frequent occurrence at 50 μg/kg compared to 25 μg/kg B(a)P dose group. On the other hand, the B(a)P alone, and AIN-76A diet groups did not show significant differences in the numbers of adenomas and invasive tumors in colon. Also, B(a)P treatment-related changes were seen in body weight and food consumption of rats administered with B(a)P, with the changes more pronounced in the body weight gain of Western diet group compared to the AIN-76A diet group and controls (p &amp;lt; 0.005). In summary, our studies established that Western diet potentiates the development of colon tumors caused by B(a)P in the PIRC rat. Citation Format: Kelly L. Harris, Mohammad S. Niaz, Awadh A. Binhazim, Mary K. Washington, Samuel E. Adunyah, Aramandla Ramesh. Obesity enhances benzo(a)pyrene-induced colon tumorigenesis in a PIRC rat model of colon cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1278. doi:10.1158/1538-7445.AM2013-1278

ESTIMATED OPERATOR EXPOSURE FOR HAND HOLDING PORTABLE X‐RAY UNITS DURING IMAGING OF THE EQUINE DISTAL EXTREMITY

Hand holding of portable X-ray units is common in large animal ambulatory veterinary practice. Portable X-ray equipment manuals, veterinary teaching institutions, and state regulations discourage, or prohibit, hand holding of portable X-ray units. Our goal was to quantify surface radiation leakage of a typical portable X-ray unit and to measure operator exposure at simulated hand and collar positions during imaging of the equine distal extremity. Each exposure for the study was performed at 80 kVp and 7.5 mAs and repeated 10 times. Measurement of tube radiation leakage was performed along each surface of the portable X-ray unit. To determine the operator exposure more accurately, an equine cadaver limb was used to generate scatter radiation for the following views: lateral carpus, lateral foot, palmaroproximal-palmarodistal, and dorsal 60° proximal-palmarodistal obliques of the navicular region. A Pancake Ion Chamber was placed at the handle and at simulated collar position to record estimated occupational exposure. To estimate the effect of lead shielding, exposure measurements were performed within the primary beam and behind a 0.5 mm lead equivalent apron and within an >0.5 mm lead equivalent glove. The average hand and collar dose was 0.471 and 0.327 mR/exposure, respectively. The lead apron and glove attenuated the primary beam 96.9 and 99.2%, respectively. This reduced average hand and collar exposures to 0.0038 and 0.0101 mR/exposure, respectively. Theoretical occupational limits are reached for the collar (whole body) before the hand (extremity).

Arsenic levels in wipe samples collected from play structures constructed with CCA-treated wood: Impact on exposure estimates

Lumber treated with chromated copper arsenate (CCA) has been used in residential outdoor wood structures and playgrounds. The U.S. EPA has conducted a probabilistic assessment of children's exposure to arsenic from CCA-treated structures using the Stochastic Human Exposure and Dose Simulation model for the wood preservative scenario (SHEDS-Wood). The EPA assessment relied on data from an experimental study using adult volunteers and designed to measure arsenic in maximum hand and wipe loadings. Analyses using arsenic handloading data from a study of children playing on CCA-treated play structures in Edmonton, Canada, indicate that the maximum handloading values significantly overestimate the exposure that occurs during actual play. The objective of our paper is to assess whether the dislodgeable arsenic residues from structures in the Edmonton study are comparable to those observed in other studies and whether they support the conclusion that the values derived by EPA using modeled maximum loading values overestimate hand exposures. We compared dislodgeable arsenic residue data from structures in the playgrounds in the Edmonton study to levels observed in studies used in EPA's assessment. Our analysis showed that the dislodgeable arsenic levels in the Edmonton playground structures are similar to those in the studies used by EPA. Hence, the exposure estimates derived using the handloading data from children playing on CCA-treated structures are more representative of children's actual exposures than the overestimates derived by EPA using modeled maximum values. Handloading data from children playing on CCA-treated structures should be used to reduce the uncertainty of modeled estimates derived using the SHEDS-Wood model.

Hand Skin Temperatures Associated with Local Hand Discomfort under Whole-body Cold Exposure

This study aimed at pointing out the local thermal effects and subjective responses to cold air exposures of gloved hands in conditions of similar hand heat loss rates. Thirteen males and 13 females, lightly clothed (0.6 clo), participated in three separated experimental sessions (once a week), while sitting for 105 min in a climatic chamber at an operative temperature of 19°C. Subjects' hands were exposed in a ventilated cold box (air velocity=2.5 m·s−1) at one of three temperatures (8°C, 10°C or 14°C) depending on the dry heat exchange coefficient of the gloved hands. The temperature of the box was chosen to induce similar heat loss rates across conditions. Main results showed that local skin temperatures can be divided in 3 categories: 4 fingers (coolest), a thumb, back and palm (least cool). Female had lower skin temperatures than males but their local thermal discomfort was found to be similar for the same local skin temperature levels. As a consequence, the durations of the accepted exposures without discomfort were shorter in females. Discrepancies between male and female responses are discussed in terms of different hand skin blood flows. A practical aspect of our results concerns the glove thermal insulations which are obviously too poor at the finger levels, a factor determinant for discomfort occurrence in case of cold hand exposures.

Radiation Hand Exposure during Restoration of Flow to the Thrombosed Dialysis Access Graft

To determine radiation dose to the hands of interventional radiologists during restoration of flow to thrombosed dialysis access grafts. Sixty-two procedures were performed in 54 patients with thrombosed synthetic arteriovenous hemodialysis access grafts. For each procedure, five staff interventional radiologists wore thermoluminescent ring dosimeters on each hand. Overall hand doses were obtained, and patient and graft factors as well as technical factors were analyzed to determine the effects on hand exposure. The mean right hand and left hand exposures were 0.78 mSv and 0.55 mSv (78 and 55 mrem), respectively, and there was a significant difference between the two (P = .01). There was a significant difference among the interventionalists, mostly based on the lower doses associated with a single operator (P < .01). Not unexpectedly, fluoroscopy times (P < .01) and, to a lesser degree, the number of angiographic runs (P = .05) were significant factors influencing hand radiation dose. Patient sex, age and location of the graft, previous thrombosis, the number of previous interventions, and success or failure of the procedure were not significant factors in hand dose. Hand exposure during the restoration of flow to thrombosed dialysis access grafts is relatively high and is greater for the right hand than for the left. The exposures are dependent on technical factors, most notably fluoroscopy times, not on patient- or graft-related factors.

Default Values for Assessment of Potential Dermal Exposure of the Hands to Industrial Chemicals in the Scope of Regulatory Risk Assessments

Dermal exposure needs to be addressed in regulatory risk assessment of chemicals. The models used so far are based on very limited data. The EU project RISKOFDERM has gathered a large number of new measurements on dermal exposure to industrial chemicals in various work situations, together with information on possible determinants of exposure. These data and information, together with some non-RISKOFDERM data were used to derive default values for potential dermal exposure of the hands for so-called 'TGD exposure scenarios'. TGD exposure scenarios have similar values for some very important determinant(s) of dermal exposure, such as amount of substance used. They form narrower bands within the so-called 'RISKOFDERM scenarios', which cluster exposure situations according to the same purpose of use of the products. The RISKOFDERM scenarios in turn are narrower bands within the so-called Dermal Exposure Operation units (DEO units) that were defined in the RISKOFDERM project to cluster situations with similar exposure processes and exposure routes. Default values for both reasonable worst case situations and typical situations were derived, both for single datasets and, where possible, for combined datasets that fit the same TGD exposure scenario. The following reasonable worst case potential hand exposures were derived from combined datasets: (i) loading and filling of large containers (or mixers) with large amounts (many litres) of liquids: 11,500 mg per scenario (14 mg cm(-2) per scenario with surface of the hands assumed to be 820 cm(2)); (ii) careful mixing of small quantities (tens of grams in <1l): 4.1 mg per scenario (0.005 mg cm(-2) per scenario); (iii) spreading of (viscous) liquids with a comb on a large surface area: 130 mg per scenario (0.16 mg cm(-2) per scenario); (iv) brushing and rolling of (relatively viscous) liquid products on surfaces: 6500 mg per scenario (8 mg cm(-2) per scenario) and (v) spraying large amounts of liquids (paints, cleaning products) on large areas: 12,000 mg per scenario (14 mg cm(-2) per scenario). These default values are considered useful for estimating exposure for similar substances in similar situations with low uncertainty. Several other default values based on single datasets can also be used, but lead to estimates with a higher uncertainty, due to their more limited basis. Sufficient analogy in all described parameters of the scenario, including duration, is needed to enable proper use of the default values. The default values lead to similar estimates as the RISKOFDERM dermal exposure model that was based on the same datasets, but uses very different parameters. Both approaches are preferred over older general models, such as EASE, that are not based on data from actual dermal exposure situations.

Distributions and determinants of pre-emergent herbicide exposures among custom applicators

Custom applicators intensively apply herbicides to corn and soybean fields each spring. The primary objective of this study was to characterize the exposure distributions of the herbicides alachlor, atrazine, 2,4-D 2-ethylhexyl ester (2,4-D EH), and metolachlor among a group of applicators during the spring pre-emergent spray season. A secondary objective was to evaluate determinants of exposure and to estimate within- and between-worker variance components. Fifteen applicators were sampled using a systematic design that included spray and non-spray days and multiple measurements (five to seven) on each applicator. Air, patch, and handwash samples were collected on 89 applicator-days. Applicator-days were classified into three categories: target herbicide sprayed, non-target herbicide sprayed, and no herbicide sprayed. Mixed-model regression analysis was used. For all exposure metrics, adjusted mean herbicide exposures were significantly higher on days when target herbicides were sprayed as compared to non-spray days. For 2,4-D EH only, adjusted mean exposures on non-target herbicide spray days were significantly higher than on non-spray days. Wearing gloves significantly reduced adjusted mean hand exposure for all herbicides (4–20 fold) and adjusted mean thigh exposure for three herbicides (8–53 fold) on days the herbicides were sprayed; however, wearing gloves significantly increased adjusted mean atrazine hand and thigh exposures (9 and 7 fold, respectively) on days that non-atrazine herbicides were sprayed. Few of the other covariates were consistent determinants of exposure. For all exposure metrics, the within-worker variability (GSDW 2.1–5.6) was greater than the between-worker variability (GSDB 1.2–2.7).

Distributions and determinants of pre-emergent herbicide exposures among custom applicators.

Custom applicators intensively apply herbicides to corn and soybean fields each spring. The primary objective of this study was to characterize the exposure distributions of the herbicides alachlor, atrazine, 2,4-D 2-ethylhexyl ester (2,4-D EH), and metolachlor among a group of applicators during the spring pre-emergent spray season. A secondary objective was to evaluate determinants of exposure and to estimate within- and between-worker variance components. Fifteen applicators were sampled using a systematic design that included spray and non-spray days and multiple measurements (five to seven) on each applicator. Air, patch, and handwash samples were collected on 89 applicator-days. Applicator-days were classified into three categories: target herbicide sprayed, non-target herbicide sprayed, and no herbicide sprayed. Mixed-model regression analysis was used. For all exposure metrics, adjusted mean herbicide exposures were significantly higher on days when target herbicides were sprayed as compared to non-spray days. For 2,4-D EH only, adjusted mean exposures on non-target herbicide spray days were significantly higher than on non-spray days. Wearing gloves significantly reduced adjusted mean hand exposure for all herbicides (4-20 fold) and adjusted mean thigh exposure for three herbicides (8-53 fold) on days the herbicides were sprayed; however, wearing gloves significantly increased adjusted mean atrazine hand and thigh exposures (9 and 7 fold, respectively) on days that non-atrazine herbicides were sprayed. Few of the other covariates were consistent determinants of exposure. For all exposure metrics, the within-worker variability (GSD(W) 2.1-5.6) was greater than the between-worker variability (GSD(B) 1.2-2.7).