Otto Melchior Poulsen

Collection of domestic waste. Review of occupational health problems and their possible causes.

During the last decade, a growing interest in recycling of domestic waste has emerged, and action plans to increase the recycling of domestic waste have been agreed by many governments. A common feature of these plans is the implementation of new systems and equipment for the collection of domestic waste which has been separated at source. However, only limited information exists on possible occupational health problems related to such new systems. Occupational accidents are very frequent among waste collectors. Based on current knowledge, it appears that the risk factors should be considered as an integrated entity, i.e. technical factors (poor accessibility to the waste, design of equipment) may act in concert with high working rate, visual fatigue due to poor illumination and perhaps muscle fatigue due to high work load. Musculoskeletal problems are also common among waste collectors. A good deal of knowledge has accumulated on mechanical load on the spine and energetic load on the cardio-pulmonary system in relation to the handling of waste bags, bins, domestic containers and large containers. However, epidemiologic studies with exposure classification based on field measurement are needed, both to further identify high risk work conditions and to provide a detailed basis for the establishment of occupational exposure limits for mechanical and energetic load particularly in relation to pulling, pushing and tilting of containers. In 1975, an excess risk for chronic bronchitis was reported for waste collectors in Geneva (Rufèner-Press et al., 1975) and data from the Danish Registry of Occupational Accidents and Diseases also indicate an excess risk for pulmonary problems among waste collectors compared with the total work force. Surprisingly few measurements of potentially hazardous airborne exposures have been performed, and the causality of work-related pulmonary problems among waste collectors is unknown. Recent studies have indicated that implementation of some new waste collection systems may result in an increased risk of occupational health problems. High incidence rates of gastrointestinal problems, irritation of the eye and skin, and perhaps symptoms of organic dust toxic syndrome (influenza-like symptoms, cough, muscle pains, fever, fatigue, headache) have been reported among workers collecting the biodegradable fraction of domestic waste. The few data available on exposure to bio-aerosols and volatile compounds have indicated that these waste collectors may be simultaneously exposed to multiple agents such as dust containing bacteria, endotoxin, mould spores, glucans, volatile organic compounds, and diesel exhaust. Several studies have reported similar health problems as well as high incidence rates of pulmonary disease among workers at plants recycling domestic waste.(ABSTRACT TRUNCATED AT 400 WORDS)

Muscle Activation and Perceived Loading During Rehabilitation Exercises: Comparison of Dumbbells and Elastic Resistance

Background High-intensity resistance training plays an essential role in the prevention and rehabilitation of musculoskeletal injuries and disorders. Although resistance exercises with heavy weights yield high levels of muscle activation, the efficacy of more user-friendly forms of exercise needs to be examined. Objective The aim of this study was to investigate muscle activation and perceived loading during upper-extremity resistance exercises with dumbbells compared with elastic tubing. Design A single-group, repeated-measures study design was used. Setting Exercise evaluation was conducted in a laboratory setting. Participants Sixteen female workers (aged 26–55 years) without serious musculoskeletal diseases and with a mean neck and shoulder pain intensity of 7.8 on a 100-mm visual analog scale participated in the study. Measurements Electromyographic (EMG) activity was measured in 5 selected muscles during the exercises of lateral raise, wrist extension, and shoulder external rotation during graded loadings with dumbbells (2–7.5 kg) and elastic tubing (Thera-Band, red to silver resistance). The order of exercises and loadings was randomized for each individual. Electromyographic amplitude was normalized to the absolute maximum EMG amplitude obtained during maximal voluntary isometric contraction and exercise testing. Immediately after each set of exercise, the Borg CR10 scale was used to rate perceived loading during the exercise. Results Resistance exercise with dumbbells as well as elastic tubing showed increasing EMG amplitude and perceived loading with increasing resistance. At the individually maximal level of resistance for each exercise—defined as the 3 repetitions maximum—normalized EMG activity of the prime muscles was not significantly different between dumbbells (59%–87%) and elastic tubing (64%–86%). Perceived loading was moderately to very strongly related to normalized EMG activity (r=.59–.92). Limitations The results of this study apply only for exercises performed in a controlled manner (ie, without sudden jerks or high acceleration). Conclusions Comparably high levels of muscle activation were obtained during resistance exercises with dumbbells and elastic tubing, indicating that therapists can choose either type in clinical practice. The Borg CR10 can be a useful aid in estimating intensity of individual rehabilitation protocols.

Sorting and recycling of domestic waste. Review of occupational health problems and their possible causes

In order to reduce the strain on the environment from the deposition of waste in landfills and combustion at incineration plants, several governments throughout the industrialized world have planned greatly increased recycling of domestic waste by the turn of the millennium. To implement the plans, new waste recycling facilities are to be built and the number of workers involved in waste sorting and recycling will increase steadily during the next decade. Several studies have reinforced the hypothesis that exposure to airborne microorganisms and the toxic products thereof are important factors causing a multitude of health problems among workers at waste sorting and recycling plants. Workers at transfer stations, landfills and incineration plants may experience an increased risk of pulmonary disorders and gastrointestinal problems. High concentrations of total airborne dust, bacteria, faecal coliform bacteria and fungal spores have been reported. The concentrations are considered to be sufficiently high to cause adverse health effects. In addition, a high incidence of lower back injuries, probably due to heavy lifting during work, has been reported among workers at landfills and incineration plants. Workers involved in manual sorting of unseparated domestic waste, as well as workers at compost plants experience more or less frequent symptoms of organic dust toxic syndrome (ODTS) (cough, chest-tightness, dyspnoea, influenza-like symptoms such as chills, fever, muscle ache, joint pain, fatigue and headache), gastrointestinal problems such as nausea and diarrhoea, irritation of the skin, eye and mucous membranes of the nose and upper airways, etc. In addition cases of severe occupational pulmonary diseases (asthma, alveolitis, bronchitis) have been reported. Manual sorting of unseparated domestic waste may be associated with exposures to large quantities of airborne bacteria and endotoxin. Several work functions in compost plants can result in very high exposure to airborne fungal spores and thermophilic actinomycetes. At plants sorting separated domestic waste, e.g. the combustible fraction of waste composed of paper, cardboard and plastics, the workers may have an increased risk of gastrointestinal symptoms and irritation of the eyes and skin. At such plants the bioaerosol exposure levels are in general low, but at some work tasks, e.g. manual sorting and work near the balers, exposure levels may occasionally be high enough to be potentially harmful. Workers handling the source-sorted paper or cardboard fraction do not appear to have an elevated risk of occupational health problems related to bioaerosol exposure, and the bioaerosol exposure is generally low.(ABSTRACT TRUNCATED AT 400 WORDS)

Effectiveness of small daily amounts of progressive resistance training for frequent neck/shoulder pain: Randomised controlled trial

&NA; Regular physical exercise is a cornerstone in rehabilitation programs, but adherence to comprehensive exercise remains low. This study determined the effectiveness of small daily amounts of progressive resistance training for relieving neck/shoulder pain in healthy adults with frequent symptoms; 174 women and 24 men working at least 30 h per week and with frequent neck/shoulder pain were randomly assigned to resistance training with elastic tubing for 2 or 12 minutes per day 5 times per week, or weekly information on general health (control group). Primary outcomes were changes in intensity of neck/shoulder pain (scale 0 to 10), examiner‐verified tenderness of the neck/shoulder muscles (total tenderness score of 0 to 32), and isometric muscle strength at 10 weeks. Compared with the control group, neck/shoulder pain and tenderness, respectively, decreased 1.4 points (95% confidence interval −2.0 to −0.7, p < 0.0001) and 4.2 points (95% confidence interval −5.7 to −2.7, p < 0.0001) in the 2‐minute group and 1.9 points (95% confidence interval −2.5 to −1.2, p < 0.0001) and 4.4 points (95% confidence interval −5.9 to −2.9, p < 0.0001) in the 12‐minute group. Compared with the control group, muscle strength increased 2.0 Nm (95% confidence interval 0.5 to 3.5 Nm, p = 0.01) in the 2‐minute group and 1.7 Nm (95% confidence interval 0.2 to 3.3 Nm, p = 0.02) in the 12‐minute group. In conclusion, as little as 2 minutes of daily progressive resistance training for 10 weeks results in clinically relevant reductions of pain and tenderness in healthy adults with frequent neck/shoulder symptoms. Trial registration: www.isrctn.org/ISRCTN60264809. In generally healthy adults with frequent neck/shoulder muscle pain, as little as 2 minutes of daily progressive resistance training reduces pain and tenderness.

Effect of physical exercise interventions on musculoskeletal pain in all body regions among office workers: A one-year randomized controlled trial

This study investigated effects of physical exercise on musculoskeletal pain symptoms in all regions of the body, as well as on other musculoskeletal pain in association with neck pain. A single blind randomized controlled trial testing a one-year exercise intervention was performed among 549 office workers; specific neck/shoulder resistance training, all-round physical exercise, or a reference intervention. Pain symptoms were determined by questionnaire screening of twelve selected body regions. Case individuals were identified for each body region as those reporting pain intensities at baseline of 3 or more (scale of 0-9) during the last three months. For neck cases specifically, the additional number of pain regions was counted. Intensity of pain decreased significantly more in the neck, low back, right elbow and right hand in cases of the two exercise groups compared with the reference group (P<0.0001-0.05). The additional number of pain regions in neck cases decreased in the two exercise groups only (P<0.01-0.05). In individuals with no or minor pain at baseline, development of pain was minor in all three groups. In conclusion, both specific resistance training and all-round physical exercise for office workers caused better effects than a reference intervention in relieving musculoskeletal pain symptoms in exposed regions of the upper body.

The aggregation-mediated conjugation system of Bacillus thuringiensis subsp. israelensis: host range and kinetics of transfer.

The aggregation-mediated conjugation system in Bacillus thuringiensis subsp. israelensis encoded on the plasmid pXO16 is characterized by the formation of aggregates when Agr+ and Agr- cells are socialized in exponential growth. Using the aggregation phenotypes, we have identified potential recipients of the aggregation-plasmid pXO16 among Bacillus cereus, Bacillus subtilis, Bacillus megaterium, Bacillus sphaericus, and 24 subspecies of B. thuringiensis. We found 14 Agr- strains, i.e., potential recipients of the aggregation system encoded by plasmid pXO16. Five strains contained a conjugative apparatus of their own and were excluded from further examinations. To monitor the transfer of plasmid pXO16, we constructed a transposon insertion of the plasmid with Tn5401. The study of the plasmid transfer of pXO16::Tn5401 indicated the secretion of bacteriocins from both donor strain and recipient strains. Only one out of the nine strains examined was unable to receive the aggregation-plasmid pXO16 and express the aggregation phenotype and the conjugative abilities. It was found that the transfer of plasmid pXO16 to Bacillus thuringiensis subsp. israelensis Agr- strains was 100%. All recipients had acquired the aggregation-plasmid pXO16 and converted to the Agr+ phenotype.

Di-(2-ethylhexyl) phthalate possesses an adjuvant effect in a subcutaneous injection model with BALB/c mice

The prevalence of allergic airway diseases is rapidly increasing in Western Europe and North America and the introduction of anthropogenic chemicals may explain a part of this increase. Recently, our group found that degradation products from several commonly used phthalate plasticizers possess adjuvant activity in an animal model. Mono-2-ethylhexyl phthalate, which is the degradation product of di-(2-ethylhexyl) phthalate (DEHP), was among these substances. These findings prompted the study of the adjuvant activity of the parent compound itself. Thus, DEHP was studied in a model using ovalbumin (OA) as the model antigen. OA was injected subcutaneously in the neck region of BALB/cJ mice with or without DEHP. The levels of OA-specific IgE, IgG1 and IgG2a antibodies in sera were measured by ELISA. Adjuvant effect, defined as a statistically significant increase in antibody level, was observed with IgG1 at a concentration of 2000 microg DEHP/ml after both one and two boosters.

Adjuvant and immuno-suppressive effect of six monophthalates in a subcutaneous injection model with BALB/c mice

The prevalence of allergic airway diseases is rapidly increasing in Western Europe and North America. This increase in disease prevalence may be associated with environmental pollutants. The present study investigated the adjuvant and immuno-suppressive effect of a series of monophthalates which are considered to be important metabolites of commonly used phthalate plasticizers. The effects were studied in a screening model. Ovalbumin (OA), used as the model antigen, was injected subcutaneously in the neck region of BALB/cJ mice with or without one of the test substances, mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBnP), mono-n-octyl phthalate (MnOP), mono-2-ethylhexyl phthalate (MEHP), mono-iso-nonyl phthalate (MiNP) or mono-iso-decyl phthalate (MiDP). The levels of OA-specific IgE, IgG1 and IgG2a in sera were measured by ELISA. Immuno-suppressive effect, defined as a statistically significant reduction in IgE or IgG1 antibody production, was observed with MEHP (1000 microg/ml, IgE and IgG1), MnOP (1000 microg/ml, IgE and IgG1), MiNP (1000 microg/ml, IgE and 10 microg/ml, IgG1) and MiDP (100 microg/ml, IgE and IgG1). Adjuvant effect, defined as a statistically significant increase in IgE or IgG1 antibody level, occurred with MEHP (10 microg/ml, IgE), MnOP (100 microg/ml, and 10 microg/ml, IgG1) and MiNP (100 microg/ml, IgE). No statistically significant immune modulating effect was seen with MBnP and MnBP.

Correlation between work process-related exposure to polycyclic aromatic hydrocarbons and urinary levels of α-naphthol, β-naphthylamine and 1-hydroxypyrene in iron foundry workers

SummaryIn two Danish iron foundries the concentration of polycyclic aromatic hydrocarbons (PAH) in 24 personal air samples of workers employed in selected processes, i.e. melters, melted iron transporters, casters, machine molders, hand molders, shake-out workers and finishing workers, were measured and correlated to levels of 1-hydroxypyrene, α-naphthol and β-naphthylamine in the urine of exposed workers. The highest total airborne PAH concentrations (sum of 15 selected PAH compounds: 9.6–11.2 μg/m3) were associated with casting, machine molding, and shake-out. The highest concentrations of the sum of six selected airborne carcinogenic PAH compounds were found for melting, casting and machine and hand molding. As seen in other working environments involving low-level PAH exposure, the content of naphthalene was high, in general exceeding 85% of the total content of PAH compounds. The present study demonstrates that 1-hydroxypyrene is a useful and direct biomarker of low-dose occupational exposure to PAH compounds. Molding and casting had the highest pyrene levels in iron foundries. Furthermore, the data shows that levels of β-naphthylamine in urine are significantly elevated in iron foundry workers. Hand molders, finishing workers and truck drivers tended to have the highest levels. Concerning α-naphthol the highest concentrations were measured in urine from casters and shake-out workers. With regard to epidemiologic studies demonstrating that molders and casters have a higher risk of lung cancer, the present study suggests that the elevated risk may be due to exposure to carcinogenic PAH compounds in iron foundries, particularly in some high-risk work processes, e.g. casting and molding. In addition, the present study suggests that biological monitoring of 1-hydroxypyrene and β-naphthylamine may be used to estimate the individual exposure, which seems to be correlated with exposure during individual work processes.

Effect of seafood consumption on the urinary level of total hydride-generating arsenic compounds. Instability of arsenobetaine and arsenocholine

Arsenobetaine and arsenocholine are considered to be non-toxic and are present as a relatively large proportion of total arsenic in seafoods, and they do not respond to hydride generation. The present study describes the effect of seafood consumption on the urinary concentration of hydride-generating arsenic compounds measured by a newly developed flow injection atomic absorption spectrometric (FI-AAS) method. Consumption of plaice, pighvar and tunny resulted in a 2-fold increase, and consumption of mussels produced a 6-fold increase in the urinary level of hydride-generating arsenic compounds. Hence, a person who has consumed mussels may be suspected of being occupationally or environmentally exposed, if the level of consumption of this seafood is unknown. As the FI-AAS method cannot be used to detect arsenobetaine and arsenocholine, the observed increase in urinary concentration of hydride-generating arsenic compounds after consumption of seafood must originate either from hydride-generating arsenic compounds in the seafood or from degraded arsenobetaine or arsenocholine. The present study has demonstrated that both arsenobetaine and arsenocholine are unstable when incubated in daylight in the presence of hydrogen peroxide, i.e., an oxidizing environment. Hence, it is tempting to speculate that arsenobetaine could be converted into hydride-generating arsenic compounds during storage or cooking of seafood. The feasibility of speciation methods based on high-performance liquid chromatographic (HPLC) separation and on-line analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) and FI-AAS was also investigated. The FI-AAS system is approximately 35 times more sensitive to the hydride-generating arsenic species than the ICP-AES system.(ABSTRACT TRUNCATED AT 250 WORDS)