Methods for evaluating temporal trends in noise exposure.

OBJECTIVE: Hearing conservation programs have been mandatory in many US industries since 1983. Since then, three program elements (audiometric testing, hearing protection, and training) have been the focus of much research. By comparison, little has been done on noise exposure evaluation. DESIGN: Temporal trends in time weighted average (TWA) exposures and the fraction of measurements exceeding 85 dBA were evaluated by facility, by exposure group within facility, and by individual worker within facility. STUDY SAMPLE: A large dataset (> 10 000 measurements over 20 years) from eight facilities operated by a multinational aluminum manufacturing company was studied. RESULTS: Overall, exposures declined across locations over the study period. Several facilities demonstrated substantial reductions in exposure, and the results of mean noise levels and exceedance fractions generally showed good agreement. The results of analyses at the individual level diverged with analyses by facility and exposure group within facility, suggesting that individual-level analyses, while challenging, may provide important information not available from coarser levels of analysis. CONCLUSIONS: Validated metrics are needed to allow for assessment of temporal trends in noise exposure. Such metrics will improve our ability to characterize, in a standardized manner, efforts to reduce noise-induced hearing loss.

Short communication: genetic evaluation of mobility for Brown Swiss dairy cattle.

Genetic parameters were estimated for mobility score and 16 linear type traits of Brown Swiss dairy cattle. Mobility is an overall assessment trait that measures a cow's ability to move, as well as the structure of her feet, pasterns, and legs. Scores from 50 to 99 were assigned by appraisers for the Brown Swiss Cattle Breeders' Association of the USA beginning in June 2007. Only scores made before 69 mo of age were used. After edits, 32,710 records were available for 19,472 cows in 819 herds. The model included fixed effects for the interaction of herd and appraisal date (2,109 groups), appraisal age within parity (46 groups), and lactation stage within parity (21 groups), as well as random effects for animal, permanent environment, and residual error. A multi-trait analysis was conducted using canonical transformation, multiple diagonalization, and a decelerated expectation-maximization REML algorithm. Heritability was estimated to be 0.21 for mobility and ranged from 0.06 to 0.37 for the other 16 type traits. The traits with the highest genetic correlation with mobility were final score (0.78), rear legs (rear view; 0.74), rear udder width (0.52), and foot angle (0.51). Predicted transmitting ability (PTA) for mobility was calculated using the Brown Swiss multi-trait type evaluation system but included only appraisals for which all traits had been scored. For the 1,868 bulls evaluated, PTA for mobility ranged from 1.6 to -1.8 with a standard deviation of 0.5 and was most highly correlated with PTA for final score (0.88), rear legs (rear view; 0.77), rear udder height (0.70), and rear udder width (0.69), as expected from the trait correlations. When matched with official US national evaluations from August 2011, PTA mobility had moderately high correlations with PTA for milk, fat, and protein yields, as well as productive life (0.31-0.41). The mobility trait may provide a more accurate assessment of the structural soundness required for longevity than does the feet-legs composite.

Evaluation and comparison of three exposure assessment techniques.

This study was conducted to verify the performance of a recently developed subjective rating (SR) exposure assessment technique and to compare estimates made using this and two other techniques (trade mean, or TM, and task-based, or TB, approaches) to measured exposures. Subjects (n = 68) each completed three full-shift noise measurements over 4 months. Individual measured mean exposures were created by averaging each subject's repeated measurements, and TM, TB, and SR estimates were created using noise levels from worksites external to the current study. The bias, precision, accuracy, and absolute agreement of estimates created using the three techniques were evaluated by comparing estimated exposures with measured exposures. Trade mean estimates showed little bias, while neither the TM nor the SR techniques produced unbiased estimates, and the SR estimates showed the greatest bias of the three techniques. Accuracy was essentially equivalent among the three techniques. All three techniques showed poor agreement with measured exposures and were not highly correlated with each other. Estimates from the SR technique generally performed similarly to the TM and TB techniques. Methods to incorporate information from each technique into exposure estimates should be explored.

Asbestos-containing materials in abandoned residential dwellings in Detroit.

OBJECTIVE: The efforts of many municipalities to demolish abandoned residential dwellings (ARDs) are hampered by the presence of asbestos-containing materials (ACMs) in these structures. However, the extent of such materials is unknown. Our study sought to characterize ACMs present in ARDs demolished in Detroit. METHODS: Working with the City of Detroit, we obtained information on all ARDs demolished from 2014 to 2017. We randomly sampled 605 ARDs and analyzed the presence, type, and amount of ACM present, and the associated abatement and demolition costs. RESULTS: Asbestos was present in about 95% of the sampled ARDs. The most common types of ACMs were flooring, roofing, siding, and duct insulation. The material containing the greatest fraction of asbestos was duct insulation. The type of asbestos generally present was chrysotile. Only eight (1%) ARDs contained commercial amphibole asbestos; another 36 contained vermiculite. The total cost of demolition averaged $13,645 per home, of which 20.1% was asbestos abatement. CONCLUSIONS: The majority of the ACM in the ARDs was nonfriable and consisted of chrysotile. This study contributes information about the nature and extent of ACM in ARDs, which can provide part of the foundation for making an assessment of possible asbestos-containing air emissions during the demolitions of ARDs, and the nature or extent of pre-demolition abatement that may be needed (if any) to protect the public's health.

Analysis of e-waste recycling behavior based on survey at a Midwestern US University.

The United States lacks a set of unified electronic waste recycling laws, contributing in part to the observed low rate of e-waste recycling behaviors among consumers. Individual factors of consumers contributing to the low recycling rates are not well understood. The objective of this study was to evaluate consumer behaviors, including barriers, surrounding e-waste recycling at a large Midwestern university in the United States. A survey was administered to faculty, graduate students, undergraduate students, and staff to determine their personal recycling habits, knowledge, and beliefs. The results indicate that free access to disposal, lack of consumer knowledge about products and disposal sites, and access to a recycling facility within a reasonable distance are all important factors in consumer decisions. Policy-makers and waste management professionals should focus on promotion of e-waste recycling behaviors through increased access to free or low-cost recycling as well as through the creation of recycling incentives.

Short communication: Genetic evaluation of milking speed for Brown Swiss dairy cattle in the United States.

Genetic parameters and relative breeding values were estimated for milking speed of US Brown Swiss dairy cattle. Owner-recorded milking-speed scores on a scale of 1 (slow) to 8 (fast) were collected by the Brown Swiss Association as part of its linear type appraisal program starting in 2004. Data were 7,366 records for 6,666 cows in 393 herds. The pedigree file included information for 21,458 animals born in 1985 or later. Six unknown-parent groups that each included 4 birth years were defined. The model included fixed effects for herd appraisal date and parity-lactation stage and random effects for permanent environment, animal, and error. Within parity (1, 2, and > or =3), 6 groups were defined: unknown calving date, four 90-d lactation stages, and lactations with >400 d in milk. Heritability of 0.22 and repeatability of 0.42 were estimated by average-information REML; residual variance was 1.13. Little trend in estimated breeding value was found for cows born from 1999 through 2002. Although solutions increased with lactation stage for first-parity cows by 0.37, no clear trend was found for later parities. Genetic evaluations for milking speed were expressed as relative breeding values with a mean of 100 and a standard deviation of 5. The 121 bulls with > or =10 daughters had milking speed evaluations that ranged from 83 to 112 and had correlations of 0.56 with productive life evaluations and -0.40 with somatic cell score evaluations. The association of faster milking speed with lower somatic cell score was not expected. The moderate heritability found for milking speed indicates that the evaluations (first released in May 2006) should be useful in detecting bulls with slow-milking daughters.

Genetic parameters and evaluation of rear legs (rear view) for Brown Swiss and Guernseys.

Genetic parameters were estimated for rear legs (rear view; RLRV) and 15 current linear type traits of Brown Swiss and Guernsey dairy cattle. The Brown Swiss Cattle Breeders' Association of the USA and the American Guernsey Association began scoring RLRV in 2004. For Brown Swiss, 8,502 records were available for 7,676 cows in 417 herds; Guernsey data included 5,437 records for 4,749 cows in 229 herds. Nine unknown-parent groups were defined for each breed, each with 2 birth years. The model included fixed effects for the interaction of herd, appraisal date, and parity; appraisal age within parity; and lactation stage within parity and random effects for animal, permanent environment, and residual error. The multitrait analysis for RLRV and the 15 linear type traits used canonical transformation, multiple diagonalization, and a decelerated expectation-maximization REML algorithm. For Brown Swiss, heritability was 0.102 for RLRV and ranged from 0.099 for rear legs (side view) to 0.453 for stature. For Guernseys, heritability ranged from 0.078 for RLRV to 0.428 for stature. For Brown Swiss, the highest genetic correlation with RLRV was 0.71 for rear udder width; the most negative correlation was -0.19 with rump angle. For Guernseys, the highest genetic correlations with RLRV were 0.43 for rear udder width and 0.42 for body depth; the most negative correlation was -0.46 with rear legs (side view). With heritability near 0.10, RLRV should be useful in selection for improved locomotion. Release of genetic evaluations for RLRV began in May 2006 for Brown Swiss and Guernseys.

Prospective noise induced changes to hearing among construction industry apprentices.

AIMS: To characterise the development of noise induced damage to hearing. METHODS: Hearing and noise exposure were prospectively monitored among a cohort of newly enrolled construction industry apprentices and a comparison group of graduate students, using standard pure tone audiometry and distortion product otoacoustic emissions (DPOAEs). A total of 328 subjects (632 ears) were monitored annually an average of 3.4 times. In parallel to these measures, noise exposure and hearing protection device (HPD) use were extensively monitored during construction work tasks. Recreational/non-occupational exposures also were queried and monitored in subgroups of subjects. Trade specific mean exposure L(eq) levels, with and without accounting for the variable use of hearing protection in each trade, were calculated and used to group subjects by trade specific exposure level. Mixed effects models were used to estimate the change in hearing outcomes over time for each exposure group. RESULTS: Small but significant exposure related changes in DPOAEs over time were observed, especially at 4 kHz with stimulus levels (L1) between 50 and 75 dB, with less clear but similar patterns observed at 3 kHz. After controlling for covariates, the high exposure group had annual changes in 4 kHz emissions of about 0.5 dB per year. Pure tone audiometric thresholds displayed only slight trends towards increased threshold levels with increasing exposure groups. Some unexpected results were observed, including an apparent increase in DPOAEs among controls over time, and improvement in behavioural thresholds among controls at 6 kHz only. CONCLUSIONS: Results indicate that construction apprentices in their first three years of work, with average noise exposures under 90 dBA, have measurable losses of hearing function. Despite numerous challenges in using DPOAEs for hearing surveillance in an industrial setting, they appear somewhat more sensitive to these early changes than is evident with standard pure tone audiometry.

Accuracy of task recall for epidemiological exposure assessment to construction noise.

AIMS: To validate the accuracy of construction worker recall of task and environment based information; and to evaluate the effect of task recall on estimates of noise exposure. METHODS: A cohort of 25 construction workers recorded tasks daily and had dosimetry measurements weekly for six weeks. Worker recall of tasks reported on the daily activity cards was validated with research observations and compared directly to task recall at a six month interview. RESULTS: The mean L(EQ) noise exposure level (dBA) from dosimeter measurements was 89.9 (n = 61) and 83.3 (n = 47) for carpenters and electricians, respectively. The percentage time at tasks reported during the interview was compared to that calculated from daily activity cards; only 2/22 tasks were different at the nominal 5% significance level. The accuracy, based on bias and precision, of percentage time reported for tasks from the interview was 53-100% (median 91%). For carpenters, the difference in noise estimates derived from activity cards (mean 91.9 dBA) was not different from those derived from the questionnaire (mean 91.7 dBA). This trend held for electricians as well. For all subjects, noise estimates derived from the activity card and the questionnaire were strongly correlated with dosimetry measurements. The average difference between the noise estimate derived from the questionnaire and dosimetry measurements was 2.0 dBA, and was independent of the actual exposure level. CONCLUSIONS: Six months after tasks were performed, construction workers were able to accurately recall the percentage time they spent at various tasks. Estimates of noise exposure based on long term recall (questionnaire) were no different from estimates derived from daily activity cards and were strongly correlated with dosimetry measurements, overestimating the level on average by 2.0 dBA.

Predictors of hearing threshold levels and distortion product otoacoustic emissions among noise exposed young adults.

AIM: To examine the relations between noise exposure and other risk factors with hearing function as measured by audiometric thresholds and distortion product otoacoustic emissions. METHODS: A total of 456 subjects were studied (393 apprentices in construction trades and 63 graduate students). Hearing and peripheral auditory function were quantified using standard, automated threshold audiometry, tympanometry, and distortion product otoacoustic emissions (DPOAEs). The analysis addressed relations of noise exposure history and other risk factors with hearing threshold levels (HTLs) and DPOAEs at the baseline test for the cohort. RESULTS: The cohort had a mean age of 27 (7) years. The construction apprentices reported more noise exposure than students in both their occupational and non-occupational exposure histories. A strong effect of age and years of work in construction was observed at 4, 6, and 8 kHz for both HTLs and DPOAEs. Each year of construction work reported prior to baseline was associated with a 0.7 dB increase in HTL or 0.2 dB decrease DPOAE amplitude. Overall, there was a very similar pattern of effects between the HTLs and DPOAEs. CONCLUSIONS: This analysis shows a relatively good correspondence between the associations of noise exposures and other risk factors with DPOAEs and the associations observed with pure-tone audiometric thresholds in a young adult working population. The results provide further evidence that DPOAEs can be used to assess damage to hearing from a variety of exposures including noise. Clarifying advantages of DPOAEs or HTLs in terms of sensitivity to early manifestations of noise insults, or their utility in predicting future loss in hearing will require longitudinal follow up.

Safety and health hazard observations in Hmong farming operations.

Agricultural workers have a high risk of occupational injuries, illnesses, and fatalities. However, there are very few standardized tools available to assess safety and health in agricultural operations. Additionally, there are a number of groups of agricultural workers, including Hmong refugees and immigrants, for which virtually no information on safety and health conditions is available. This study developed an observation-based methodology for systematically evaluating occupational health and safety hazards in agriculture, and pilot-tested this on several small-scale Hmong farming operations. Each observation assessed of range of safety and health hazards (e.g., musculoskeletal hazards, dust and pollen, noise, and mechanical hazards), as well as on factors such as type of work area, presence of personal protective equipment, and weather conditions. Thirty-six observations were collected on nine farms. The most common hazards observed were bending at the back and lifting <50 pounds. Use of sharp tools without adequate guarding mechanisms, awkward postures, repetitive hand motions, and lifting >50 pounds were also common. The farming activities observed involved almost no power equipment, and no pesticide or chemical handling was observed. The use of personal protective equipment was uncommon. The results of this assessment agreed well with a parallel study of perceived safety and health hazards among Hmong agricultural workers. This study suggests that small-scale Hmong farming operations involve a variety of hazards, and that occupational health interventions may be warranted in this community. The study also demonstrates the utility of standardized assessment tools and mixed-method approaches to hazard evaluation.

Biological monitoring of smoke exposure among wildland firefighters: a pilot study comparing urinary methoxyphenols with personal exposures to carbon monoxide, particular matter, and levoglucosan.

Urinary methoxyphenols (MPs) have been proposed as biomarkers of woodsmoke exposure. However, few field studies have been undertaken to evaluate the relationship between woodsmoke exposure and urinary MP concentrations. We conducted a pilot study at the US Forest Service-Savannah River Site, in which carbon monoxide (CO), levoglucosan (LG), and particulate matter (PM(2.5)) exposures were measured in wildland firefighters on prescribed burn days. Pre- and post-shift urine samples were collected from each subject, and cross-shift changes in creatinine-corrected urinary MP concentrations were calculated. Correlations between exposure measures and creatine-adjusted urinary MP concentrations were explored, and regression models were developed relating changes in urinary MP concentrations to measured exposure levels. Full-shift measurements were made on 13 firefighters over 20 work shifts in winter 2004 at the US Forest Service Savannah River site, a National Environmental Research Park. The average workshift length across the 20 measured shifts was 701+/-95 min. LG and CO exposures were significantly correlated for samples where the filter measurement captured at least 60% of the work shift (16 samples), as well as for the smaller set of full-shift exposure samples (n=9). PM(2.5) and CO exposures were not significantly correlated, and LG and PM(2.5) exposures were only significantly correlated for samples representing at least 60% of the work shift. Creatinine-corrected urinary concentrations for 20 of the 22 MPs showed cross-shift increases, with 14 of these changes showing statistical significance. Individual and summed creatinine-adjusted guaiacol urinary MPs were highly associated with CO (and, to a lesser degree, LG) exposure levels, and random-effects regression models including CO and LG exposure levels explained up to 80% of the variance in cross-shift changes in summed creatinine-adjusted guaiacol urinary MP concentrations. Although limited by the small sample size, this pilot study demonstrates that urinary MP concentrations may be effective biomarkers of occupational exposure to wood smoke among wildland firefighters.

High-level expression of a recombinant protein in Klebsiella planticola owing to induced secretion into the culture medium.

The Tn5-based transposon Tn5-KIL3 (Miksch et al. 1997c) bearing the kil gene of the ColE1 plasmid of Escherichia coli, which mediates controlled export of periplasmic proteins into the culture medium, was stably integrated into the chromosome of Klebsiella planticola with high transposition frequency. A Bacillus hybrid beta-glucanase located on an RSF1010-derived plasmid was mobilized from E. coli to K. planticola and used as a reporter protein to select strains with high expression and secretion competence. During fermentation experiments it was shown that the production of beta-glucanase in K. planticola was improved to an unexpectedly high level when the enzyme was secreted into the medium. Due to the stationary-phase promoter used for the expression of the kil gene the secretion of beta-glucanase into the medium started at the transition from the exponential to the stationary phase, as in E. coli, and the fraction of secreted protein reached 90%. The results showed that K. planticola may represent an interesting organism for the production of heterologous proteins.

Energy and phosphorus status as factors affecting postpartum performance and health of dairy cows.

To determine if energy and phosphorus status would affect postpartum health and lactational performance, first-calf heifers were assigned at parturition, 12 per group, to either high (135% of requirement) or low (85% of requirement) energy, high (138% of requirement) or adequate (98% of requirement) phosphorus in a 2 X 2 factorial design. Treatments extended 84 days postpartum after which standard rations were fed. Milk yields were similar until wk 5 of lactation. From wk 5 to 12, cows fed adequate phosphorus (98% of requirement) yielded 1.8 kg/day more milk than high phosphorus groups. Energy did not affect milk yield until wk 9 when persistency of low energy groups declined. High energy groups had almost twice as much disease and higher rectal temperatures than low energy groups in the first 3 mo of lactation. All heifers had temperatures above expected during the 1st mo of lactation. Excess energy should be avoided for the 1st mo of lactation and then gradually increased. Phosphorus should be fed as recommended and no more.

An assessment of occupational noise exposures in four construction trades.

Three hundred thirty-eight noise exposure samples were collected from 133 construction workers employed in 4 construction trades: carpenters, laborers, ironworkers, and operating engineers. Four sites using a variety of construction techniques were sampled at least 12 times on a randomly chosen date over a 22-week period. Up to 10 volunteer workers were sampled for an entire work shift on each sampling day using datalogging noise dosimeters, which recorded both daily time-weighted averages (TWAs) and 1-min averages. Workers also completed a questionnaire throughout the workday detailing the tasks performed and tools used throughout the day. Regression models identified work characteristics associated with elevated exposure levels. Comparisons were made between exposures measured using the Occupational Safety and Health Administration (OSHA) exposure metric and the 1996 draft National Institute for Occupational Safety and Health/International Organization for Standardization (NIOSH/ISO) metric to examine the effects of differing exchange rates and instrument response times on construction noise exposures. The mean OSHA TWA for 338 samples was 82.8 dBA +/- 6.8 dBA, whereas the mean NIOSH/ISO TWA for 174 samples was 89.7 dBA +/- 6.0 dBA. Forty percent of OSHA TWAs exceeded 85 dBA, and 13% exceeded 90 dBA, the OSHA permissible exposure limit. The tasks and tools associated with the highest exposure levels were those involving pneumatically operated tools and heavy equipment. Trade was a poor predictor of noise exposure; construction method, stage of construction, and work tasks and tools used were found to be better exposure predictors. An internal validation substudy indicated excellent agreement between worker self-reporting and researcher observation. These data provide substantial documentation that construction workers in several key trades are frequently exposed to noise levels that have been associated with hearing loss, and demonstrate the need for targeted noise reduction efforts and comprehensive hearing conservation programs in the industry.

Inheritance of calf mortality for Brown Swiss cattle.

Worksheets with reports of calf mortality were voluntarily submitted by dairy producers to the Brown Swiss Cattle Breeders Association. Objective was to assess genetic and nongenetic factors influencing calf mortality of Brown Swiss. Multiple births were removed prior to analysis. Three traits recorded and analyzed were dead at birth, death through 2nd d after birth including dead at birth, and death from 1st to 7th d of life. Male calves were more likely to be dead at birth, to die through 2nd d, and to die from 1st to 7th d of life than female calves. Dead birth was greater for calves from primiparous than multiparous dams; however, death from 1st to 7th d did not differ by parity status of dam. Death from 1st to 7th d was greater from December to May than from June to November. Heritabilities for Brown Swiss were .05, .07, and .04 for dead at birth, dead through 2nd d, and death from 1st to 7th d, respectively. Mortality rates and heritabilities were similar to estimates for Holsteins from the literature. Rank correlations of sires for transmitting abilities of calf mortality and production were near zero.

A review of crane safety in the construction industry.

The complex, dynamic, and continually changing nature of construction work has been recognized as an important contributor to the high rates of injuries and fatalities in the industry. Cranes are a central component of many construction operations and are associated with a large fraction of construction deaths; in fact, estimates suggest that cranes are involved in up to one-third of all construction and maintenance fatalities. Safety and health professionals serving the construction industry need adequate training and knowledge regarding available crane safety devices and procedures so that they may insure these techniques are effectively utilized during construction operations. This paper reviews available information on crane-related injuries, currently available safety devices, and commonly used crane safety procedures. Recommendations for improved crane injury prevention and future crane safety research are given.

Noise exposure among construction electricians.

Data-logging noise dosimetry was used to assess the exposure levels of electricians working for a major electrical subcontractor in Washington State at five sites using four types of construction methods. Subjects documented activities and work environment information throughout their work shift, resulting in an activity/exposure record for each of the 174 full-shift samples collected over the 4-month duration of the study. Over 24% of the TWA samples exceeded 85 dBA; 5.2% exceeded the federal Occupational Safety and Health Administration permissible exposure limit of 90 dBA. The National Institute for Occupational Safety and Health exposure metric, which specifies a 3-dB ER, was also utilized; using this metric, 67.8% of the samples exceeded 85 dBA and 27% exceeded 90 dBA. Subjects were directly observed for a subset of 4469 min during which more detailed activity and environmental information was recorded. Linear and logistic regression models using this subset were used to identify the determinants of average exposure, and exposure exceedences, respectively. These models demonstrated the importance of multiple variable modeling in interpreting exposure assessments, and the feasibility and utility of modeling exposure exceedences using logistic regression. The results further showed that presumably quiet trades such as electrician are at risk of exposure to potentially harmful noise exposures, and that other workers' activities and the general environment contribute substantially to that risk. These results indicate that noise control strategies will have to address the construction work environment as an integrated system.

Extracellular production of a hybrid beta-glucanase from Bacillus by Escherichia coli under different cultivation conditions in shaking cultures and bioreactors.

Cultivation conditions for the extracellular production of a hybrid beta-glucanase from Bacillus were established by using Escherichia coli JM 109 carrying the plasmid pLF3. This plasmid contained a novel secretion system consisting of the kil gene (killing protein) of plasmid ColE1 under the stationary-phase promoter of either the fic or the bolA gene, an omega interposon (Prentki and Krisch 1984) located upstream of the promoters and a hybrid beta-glucanase gene of Bacillus. When controlled by the fic promoter, the kil gene led to a higher total production of beta-glucanase and a higher protein secretion than when it was under control of the bolA promoter. When the effect of different distances between the stationary-phase promoters and the kil gene was investigated, a shorter distance was generally found to result in a higher secretion. With a complex growth medium, the kinetics of extracellular production of the enzyme depended on several operating variables, such as the salt concentration (NaCl) and the oxygen supply, which were varied by changing the culture volume and the shaking speed. In defined media the secretion of beta-glucanase into the medium was increased significantly by the addition of glycerol as a carbon source and by prolonged cultivation. The strain with the highest production and secretion yield of beta-glucanase [E. coli JM 109(pLF3)] was tested on the fermenter scale.