Biological Monitoring

Biological Monitoring

Wednesday, June 3, 2015, 10:00 AM - 12:00 PM

CS-121-01 Regulatory, Legal, and Analytical Considerations for Assessing Consumer Risk from Titanium Dioxide in Personal Care Products

J. Persky, ENVIRON International Corp., Chicago, IL; L. Haroun, ENVIRON International Corp., Emeryville, CA

Situation/Problem: Risk assessment in the context of California Prop65 regulations may at times require a prima facie determination of exposure in the absence of a crite​​rion value for dose. Competing regulatory, legal, and scientific influences introduce challenges to the risk assessment process. To determine whether consumer exposures to respirable TiO2 are detectable during the use of personal care products, we developed an exposure assessment strategy based upon the fundamental scientific principles described in NIOSH Current Intelligence Bulletin 63. The sampling strategy and analytical methods were scrutinized based upon the selected exposure metric and associated detection limits.

Resolution: Five consumer products were evaluated in a series of isolation-chamber studies representative of 4 cosmetic product categories, including face powder, eye shadow, nail powder, and sunscreen. Multiple data points were generated by conducting 18 independent task-duration exposure assessments.

Results: All analytical results were non-detect, thus demonstrating that the presence of TiO2 in a bulk product does not directly correlate to a consumer inhalation exposure at a concentration which is relevant from a risk-based perspective. Study variables, such as applied product mass and application frequency, were found to be consistent with historical trade-association data from a survey of over 10,000 U.S. women.

Lessons Learned: Study design and analytical method selection in the absence of a criterion for data interpretation presents a significant challenge, especially when confronted with regulatory processes which influence the scientific research approach. Nonetheless, a defensible exposure assessment strategy may be developed based upon relevant toxicological data coupled with realistic exposure factors. The distinctions between novel scientific research and agency-sanctioned analytical methods are critically important to the development of a study design which meets Prop65 regulatory intent.

SR-121-02 Measuring Broad Relationships across Mining Citation and Injury Data from 1983-2012<

R. Reed, M. Savit, E. Lutz, University of Arizona, Tucson, AZ

Objective: As the reduction in injury rates in modern years slows, many question the role of the Mining Safety and Health Administration (MSHA) in improving safety and health. This pilot work aimed to measure the existing correlations among MSHA citation and mining injury data from 1983-2012 in an effort to understand the role mining regulatory compliance plays in preventing injury.

Methods: This study analyzed basic associations between annual MSHA regulatory compliance- and injury-related data from 1983-2012 obtained from the online injury and U.S. Department of Labor’s enforcement databases. Operator and contractor injury data were combined, and data for office workers were included. Seven compliance and production ‘inputs’ were utilized, including citations (excluding serious and substantial citations [CT]), SNS citations (SCT), orders, SNS orders, inspection hours, penalty amounts, and production. All compliance measures were unadjusted by the number of operations, miners, or full-time equivalent. Eight injury ‘outcomes’ were considered, including fatal injuries, fatality incidence rate, non-fatal-days-lost (NFDL) injuries, NFDL incidence rate, no-days-lost (NDL) injuries, NDL incidence rate, all injuries, and all injury incidence rate. Correlation coefficients were determined using the Spearman’s rank test for the entire period and by decade. Further modeling was performed using the General Estimating Equation. An alpha error threshold of 0.05 was utilized.

Results: In most cases, CT were negatively (rs=-0.64 to -0.82, p<0.05) correlated with multiple injury outcomes during the 1st and 3rd decades, with no correlation during the 2nd. Generally, SCT were positively (rs=0.78 to 0.92, p<0.05) correlated during the 1st and 2nd decades, with virtually no correlation for the 3rd. Overall, orders correlated negatively during the 1st and 3rd decades (rs=-0.64 to -0.79, p<0.05), and positively during the 2nd decade (rs=0.64 to 0.77, p<0.05).

Conclusions: Negative correlations suggest that increasing regulatory compliance is related to decreasing injury outcomes, while positive correlations suggest the reverse: decreasing compliance is associated with injury reduction. This study was not designed to demonstrate causation; rather, it simply measures correlation between MSHA regulatory activities and mining injury outcomes, but sheds light on the broad relationships between regulatory compliance and injury outcomes.

SR-121-03 Heat Index and Adjusted Temperature as Surrogates for Wet Bulb Globe Temperature to Screen for Occupational Heat Stress

T. Bernard, I. Iheanacho,  University of South Florida, Tampa, FL

Objective: Ambient temperature and relative humidity are readily available; and thus tempting metrics for heat stress assessment. Two methods of using air temperature and relative humidity to create an index are Heat Index and Adjusted Temperature. The purposes of this research were: (1) to examine how well Heat Index and Adjusted Temperature estimated the wet bulb globe temperature (WBGT) index and (2) to suggest how Heat Index and Adjusted Temperature can be used to screen for heat stress level.

Methods: For conditions relevant to Heat Index and Adjusted Temperature, psychrometric relationships were used to estimate values of actual WBGT for conditions of air temperature, relative humidity, and radiant heat at an air speed of 0.5 m/s.

Results: A relationship between Heat Index [°F] and WBGT [°C] was described by WBGT = -0.0034 HI2 + 0.96 HI - 34. At lower Heat Index values, the equation estimated WBGTs that were ±2°C-WBGT around the actual value; and to about ±0.5°C-WBGT for Heat Index values > 100°F. A relationship between Adjusted Temperature [°F] and WBGT [°C] was described by WBGT = 0.45 Tadj - 16. The actual WBGT was between 1°C-WBGT below the estimated value and 1.4°C-WBGT above. That is, there was a slight bias toward overestimating WBGT from Adjusted Temperature. Heat stress screening tables were constructed for metabolic rates of 180, 300, and 450 W. The screening decisions were divided into four categories: (1) < alert limit; (2) < exposure limit; (3) hourly time-weighted averages of work and recovery; and (4) a Caution zone for an exposure > exposure limit at rest.

Conclusions: The authors do not recommend using Heat Index or Adjusted Temperature instead of WBGT, but they may be used to screen for circumstances when a more detailed analysis using WBGT is appropriate. A particular weakness is accounting for radiant heat; and neither air speed nor clothing was considered.

SR-121-04 Piloting Infrared Technologies for Measuring Body Temperature in High School Football Players

R. Reed, O. Quiroz, E. Lutz, University of Arizona, Tucson, AZ

Objective: While personal heat strain monitoring can be an effective way of detecting physiologic strain in occupational or athletic settings, many of the most accurate and current solutions are invasive, inconvenient, and/or expensive. This study aimed to explore and correlate the use of infrared (IR) thermometry (IRM) and thermography (IRG) with tympanic thermometry (TPM) in an athletic setting. 

Methods: Eleven male high school football players (six wide receivers, three linemen, one quarterback, and one defensive back) in the desert southwest were recruited and then monitored over four days in August. Pre-, mid-, and post-practice measurements were taken using a conventional tympanic thermometer, industrial IR thermometer, and IR camera. Pre-practice measurements were taken in the locker room, while mid- and post-practice measurements occurred on the sidelines. For this study, TPM was used in lieu of more accurate, invasive heat strain monitoring methods, and were taken according to manufacturer instructions. For IRM measurements, the investigators scanned various portions of the players’ faces for approximately 10 seconds, from a distance of one meter, and the maximum observed temperature was recorded. IR thermographs were analyzed and the maximum facial temperature and location recorded. Results for combined mid- and post-practice measurements are reported. Pearson’s Correlation Coefficients were computed utilizing an alpha error threshold of 0.05. 

Results: The mean TPM, IRM, and IRG temperatures were 36.8 ±0.44°, 35.5 ±0.86°, and 37.1 ±0.80° Celsius, respectively. Overall, the IRM correlated significantly (p=0.004) with TPM, albeit weakly (r=0.356). Likewise, the IRG was significantly correlated to TPM (p<0.001) with a weak coefficient (r=0.475). Mixed results were observed for pre-practice measurements, with IRG significantly correlated to TPM (r=0.766, p<0.001) while IRM was not (r=0.305, p=0.138). Mid- and post-practice TPM measurements were significantly correlated for both IR devices (p<0.05) but with similarly weak coefficients (r=0.37 for both).

Conclusions: One possible explanation for the generally stronger correlation of IRG as compared to IRT is the ability to locate the warmest portion of the face with software. The pre-practice IRG was more strongly correlated with TPM than mid- and post-practice measures. This study lays groundwork for future investigation of IR technologies in heat strain monitoring. 

CS-121-05 Chemical Sensitizer Sampling and Exposure Control Strategies

T. Morris, Morris Innovative IH & Safety Solutions, Cincinnati, OH

Situation/Problem: Occupational asthma (OA) and allergic contact dermatitis (ACD) continue to be important work-related diseases in spite of low OELs and exposure control methods. Controls follow route of exposure and target organ: LEV and respirators for respiratory sensitizers and gloves for dermal sensitizers. Sensitizers are treated the same with no distinctions based on potency, concentration or other relevant workplace conditions. Clearly this approach is lacking and other techniques are needed.

Resolution: Immunotoxicology work has refined our understanding of sensitization and has resulted in a reassessment of sensitizer route of exposure and control methods in light of animal/human evidence of respiratory sensitization via skin contact and dermal sensitization via inhalation. The mouse LLNA can identify a SEN and quantify its potency; the resulting µg/cm2 dose metric (EC3) can be used in a risk assessment (as in the personal care products industry). Peak/high exposures are most likely to produce sensitization and indicate task-based or upset condition sampling must supplement full shift sampling. Rarely considered are occlusion (i.e., gloves) or irritant chemical use, both of which facilitate sensitization, are common in workplace environments, and are important site- and industry-specific induction factors.

Results: Reduction in airborne levels of some sensitizers has not significantly reduced the incidence of sensitization. Skin contact has been shown to be an important sensitization route for Be and the isocyanates, historically only associated with inhalation exposure. Sensitizer potencies span five orders of magnitude, yet the control methods and PPE selected are all the same.

Lessons Learned: Chemical sensitizer exposure assessment and control should include all routes of exposure (emphasizing the main target organ). Focus has expanded to include work surface and tool contamination, exposures during PPE removal and non-production task exposures. Sensitizers’ mode of action, potency data and process characteristics (i.e., irritant chemical exposure, concentrated or dilute) should be coupled with task-based and full shift air sampling and wipe sampling. Only after a thorough exposure assessment can resources be directed to high risk activities, worker education and more complete protection so OA/ACD are prevented.

SR-121-06 Evaluation of a Button Inhalable Sampler with a Grimm Monitor to Determine Air Concentrations of Subtilisin

J. Cross, CBI Federal Services, Clifton Park, NY

Objective: Currently, there is no OSHA or NIOSH monitoring method for subtilisin. This study evaluated a personal aerosol monitoring method for detection and quantification of subtilisin. The ACGIH ceiling limit and NIOSH Short Term Exposure Limit (STEL) for subtilisin is 0.06 μg/m3. This study specifically evaluated the use of an SKC Button inhalable aerosol sampler with a Grimm Aerosol Monitor for monitoring low concentrations of subtilisin particulates in air within a laundry detergent production facility.

Methods: Air samples of detergent with subtilisin were collected using a Button sampler containing a glass fiber filter concurrently with a Grimm model 1.109 Aerosol Spectrometer. Nineteen sampling events of 4 hours each were performed over a seven week period, with three Button samplers operating simultaneously. Sampling locations included a detergent containing subtilisin (DCS) production area and a specially constructed enclosure where DCS was introduced in a controlled manner. Sample analysis was conducted with a Konelab Arena 20 analyzer to quantify the amount of subtilisin collected on the filter of each air sample.

Results: A linear regression for the concentration of DCS aerosol measured in the enclosure by the Grimm was compared to the average concentration of DCS aerosol measured on the Button filter in the enclosure, which produced an R2 value of 0.64 (p value = 0.006). The Pearson’s correlation produced an r value of 0.8 (p value = 0.006). The linear regression for the average concentrations of DCS aerosol measured on the Button filter media compared to the average subtilisin detected from the aerosol in the enclosure produced an R2 value of 0.66 (p value = 0.004). The Pearson’s correlation produced an r value of 0.81 (p value = 0.004).

Conclusions: The results of the statistical evaluation from the aerosol monitoring results in the enclosure indicate the Button inhalable sampler compared with the results from the Grimm aerosol monitor may be a valid method for determining airborne subtilisin concentrations for aerosols with diameters less than or equal to the 25 μm particle size. However, due to all results below the limit of quantitation at the DCS production area, it is concluded that there are insufficient results to determine if the Button sampler with the Grimm aerosol monitor can be used in the workplace.​