Neuropsychological symptoms in workers handling cargo from shipping containers and export logs.

PURPOSE: Acute poisonings of workers handling shipping containers by fumigants and other harmful chemicals off-gassed from cargo have been reported but (sub)-chronic neuropsychological effects have not been well studied. METHODS: This cross-sectional study assessed, using standardised questionnaires, current (past 3-months) neuropsychological symptoms in 274 container handlers, 38 retail workers, 35 fumigators, and 18 log workers, all potentially exposed to fumigants and off-gassed chemicals, and a reference group of 206 construction workers. Prevalence odds ratios (OR), adjusted for age, ethnicity, smoking, alcohol consumption, education, personality traits and BMI, were calculated to assess associations with the total number of symptoms (≥ 3, ≥ 5 or ≥ 10) and specific symptom domains (neurological, psychosomatic, mood, memory/concentration, fatigue, and sleep). RESULTS: Compared to the reference group, exposed workers were more likely to report ≥ 10 symptoms, statistically significant only for retail workers (OR 6.8, 95% CI 1.9-24.3) who also reported more fatigue (OR 10.7, 95% CI 2.7-42.7). Container handlers with the highest exposure-duration were more likely to report ≥ 10 symptoms, both when compared with reference workers (OR 4.0, 95% CI 1.4-11.7) and with container handlers with shorter exposure duration (OR 7.5, 95% CI 1.7-32.8). The duration of container handling was particularly associated with symptoms in the memory/concentration domain, again both when compared to reference workers (OR 8.8, 95% CI 2.5-31.4) and workers with the lowest exposure-duration (OR 6.8, 95% CI 1.5-30.3). CONCLUSION: Container handlers may have an increased risk of neuropsychological symptoms, especially in the memory/concentration domain. Retail workers may also be at risk, but this requires confirmation in a larger study.

Respiratory symptoms and use of dust-control measures in New Zealand construction workers - A cross-sectional study.

Dust-exposed construction workers have an increased risk of respiratory symptoms, but the efficacy of dust-control measures remains unclear. This study compared respiratory symptoms, using a modified European Community Respiratory Health Survey questionnaire, between construction workers (n = 208) and a reference group of bus drivers and retail workers (n = 142). Within the construction workers, we assessed the effect of collective (on-tool vacuum/'wet-cut' systems) and personal (respirators) exposure controls on symptom prevalence. Logistic regression assessed differences between groups, adjusted for age, ethnicity, and smoking status. Construction workers were more likely to cough with phlegm at least once a week (OR 2.4, 95% CI 1.2-4.7) and cough with phlegm ≥3 months/year for ≥2 years (OR 2.8, CI 1.2-7.0), but they had similar or fewer asthma symptoms. Construction workers who had worked for 11-20 years reported more cough/phlegm symptoms (OR 5.1, 1.7-15.0 for cough with phlegm ≥3 months/year for ≥2 years) than those who had worked <10 years (OR 1.9, 0.6-5.8), when compared to the reference group. Those who used 'wet-cut' methods reported less cough with phlegm, although the evidence for this association was weak (OR 0.4, CI 0.2-1.1 for cough with phlegm at least once a week); use of on-tool extraction showed a similar trend. No associations between respiratory protective equipment-use and symptoms were found. In conclusion, construction workers reported more symptoms suggestive of bronchitis, particularly those employed in the industry for >10 years. Use of collective dust exposure controls might protect against these symptoms, but this requires confirmation in a larger study.

Occupational exposures to pesticides and other chemicals: a New Zealand motor neuron disease case-control study.

OBJECTIVES: To assess associations between occupational exposures to pesticides and other chemicals and motor neuron disease (MND). METHODS: A population-based case-control study that included 319 MND cases (64% male/36% female) recruited through the New Zealand MND Association complemented with hospital discharge data, and 604 controls identified from the Electoral Roll. For each job held, a questionnaire collected information on 11 exposure categories (dust, fibres, tobacco smoke, fumes, gas, fumigants, oils/solvents, acids/alkalis, pesticides, other chemicals and animals/animal products). ORs were estimated using logistic regression adjusting for age, sex, ethnicity, socioeconomic status, education, smoking, alcohol consumption, physical activities, head/spine injury and other occupational exposures. RESULTS: Two exposure categories were associated with increased MND risks: pesticides (OR 1.70, 95% CI 1.17 to 2.48) and fumigants (OR 3.98, 95% CI 1.81 to 8.76), with risks increasing with longer exposure duration (p<0.01). Associations were also observed for: methyl bromide (OR 5.28, 95% CI 1.63 to 17.15), organochlorine insecticides (OR 3.28, 95% CI 1.18 to 9.07), organophosphate insecticides (OR 3.11, 95% CI 1.40 to 6.94), pyrethroid insecticides (OR 6.38, 95% CI 1.13 to 35.96), inorganic (copper) fungicides (OR 4.66, 95% CI 1.53 to 14.19), petrol/diesel fuel (OR 2.24, 95% CI 1.27 to 3.93) and unspecified solvents (OR 1.91, 95% CI 1.22 to 2.99). In women, exposure to textile fibres (OR 2.49, 95% CI 1.13 to 5.50), disinfectants (OR 9.66, 95% CI 1.29 to 72.44) and cleaning products (OR 3.53, 95% CI 1.64 to 7.59) were also associated with MND; this was not observed in men (OR 0.80, 95% CI 0.44 to 1.48; OR 0.72, 95% CI 0.29 to 1.84; OR 0.57, 95% CI 0.21 to 1.56, respectively). CONCLUSIONS: This study adds to the evidence that pesticides, especially insecticides, fungicides, and fumigants, are risk factors for MND.

Sports and trauma as risk factors for Motor Neurone Disease: New Zealand case-control study.

OBJECTIVES: To assess whether sports, physical trauma and emotional trauma are associated with motor neurone disease (MND) in a New Zealand case-control study (2013-2016). METHODS: In total, 321 MND cases and 605 population controls were interviewed collecting information on lifetime histories of playing sports, physical trauma (head injury with concussion, spine injury) and emotional trauma (14 categories). ORs were estimated using logistic regression adjusting for age, sex, ethnicity, socioeconomic status, education, smoking status, alcohol consumption and mutually adjusting for all other exposures. RESULTS: Head injury with concussion ≥3 years before diagnosis was associated with MND (OR 1.51, 95% CI: 1.09-2.09), with strongest associations for two (OR 4.01, 95% CI: 1.82-8.86), and three or more (OR 2.34, 95% CI: 1.00-5.45) head injuries. Spine injury was not associated with MND (OR 0.81, 95% CI: 0.48-1.36). Compared to never playing sports, engaging in sports throughout childhood and adulthood increased MND risk (OR 1.81, 95% CI: 1.01-3.25), as was more than 12 years playing football/soccer (OR 2.35, 95% CI: 1.19-4.65). Reporting emotionally traumatic events in more than three categories was associated with MND (OR 1.88, 95% CI: 1.17-3.03), with physical childhood abuse the only specific emotional trauma associated with MND (OR 1.82, 95% CI: 1.14-2.90), particularly for those reporting longer abuse duration (OR(5-8 years) 2.26, 95% CI: 1.14-4.49; OR(>8 years) 3.01, 95% CI: 1.18-7.70). For females, having witnessed another person being killed, seriously injured or assaulted also increased MND risk (OR 2.68, 95% CI: 1.06-6.76). CONCLUSIONS: This study adds to the evidence that repeated head injury with concussion, playing sports in general, and playing football (soccer) in particular, are associated with an increased risk of MND. Emotional trauma, that is physical abuse in childhood, may also play a role.

Airborne Fumigants and Residual Chemicals in Shipping Containers Arriving in New Zealand.

BACKGROUND: Airborne fumigants and other hazardous chemicals inside unopened shipping containers may pose a risk to workers handling containers. METHODS: Grab air samples from 490 sealed containers arriving in New Zealand were analysed for fumigants and other hazardous chemicals. We also collected grab air samples of 46 containers immediately upon opening and measured the total concentration of volatile organic compounds in real-time during ventilation. Additive Mixture Values (AMV) were calculated using the New Zealand Workplace Exposure standard (WES) and ACGIH Threshold Limit Values (TLV) of the 8-h, time-weighted average (TWA) exposure limit. Regression analyses assessed associations with container characteristics. RESULTS: Fumigants were detectable in 11.4% of sealed containers, with ethylene oxide detected most frequently (4.7%), followed by methyl bromide (3.5%). Other chemicals, mainly formaldehyde, were detected more frequently (84.7%). Fumigants and other chemicals exceeded the WES/TLV in 6.7%/7.8%, and 7.8%/20.0% of all containers, respectively. Correspondingly, they more frequently exceeded '1' for the AMV-TLV compared to the AMV-WES (25.7% versus 7.8%). In samples taken upon opening of doors, fumigants were detected in both fumigated and non-fumigated containers, but detection frequencies and exceedances of the WES, TLV, and AMVs were generally higher in fumigated containers. Detection frequencies for other chemicals were similar in fumigated and non-fumigated containers, and only formaldehyde exceeded both the WES and TLV in both container groups. Volatile compounds in container air reduced rapidly during ventilation. Some cargo types (tyres; personal hygiene, beauty and medical products; stone and ceramics; metal and glass; and pet food) and countries of origin (China) were associated with elevated airborne chemical and fumigant concentrations. CONCLUSION: Airborne chemicals in sealed containers frequently exceed exposure limits, both in fumigated and non-fumigated containers, and may contribute to short-term peak exposures of workers unloading or inspecting containers.

Associations of Occupational Exposures to Electric Shocks and Extremely Low-Frequency Magnetic Fields With Motor Neurone Disease.

In a New Zealand population-based case-control study we assessed associations with occupational exposure to electric shocks, extremely low-frequency magnetic fields (ELF-MF) and motor neurone disease using job-exposure matrices to assess exposure. Participants were recruited between 2013 and 2016. Associations with ever/never, duration, and cumulative exposure were assessed using logistic regression adjusted for age, sex, ethnicity, socioeconomic status, education, smoking, alcohol consumption, sports, head or spine injury, and solvents, and was mutually adjusted for the other exposure. All analyses were repeated stratified by sex. An elevated risk was observed for having ever worked in a job with potential for electric shocks (odds ratio (OR) = 1.35, 95% confidence interval (CI): 0.98, 1.86), with the strongest association for the highest level of exposure (OR = 2.01, 95% CI: 1.31, 3.09). Analysis by duration suggested a nonlinear association: Risk was increased for both short duration (<3 years; OR = 4.69, 95% CI: 2.25, 9.77) and long duration (>24 years; OR = 1.88; 95% CI: 1.05, 3.36) in a job with high level of electric shock exposure, with less pronounced associations for intermediate durations. No association with ELF-MF was found. Our findings provide support for an association between occupational exposure to electric shocks and motor neurone disease but did not show associations with exposure to work-related ELF-MF.

Exposures to Fumigants and Residual Chemicals in Workers Handling Cargo from Shipping Containers and Export Logs in New Zealand.

OBJECTIVES: Previous studies have reported high concentrations of airborne fumigants and other chemicals inside unopened shipping containers, but it is unclear whether this is reflective of worker exposures. METHODS: We collected personal 8-h air samples using a whole-air sampling method. Samples were analysed for 1,2-dibromoethane, chloropicrin, ethylene oxide, hydrogen cyanide, hydrogen phosphide, methyl bromide, 1,2-dichloroethane, C2-alkylbenzenes, acetaldehyde, ammonia, benzene, formaldehyde, methanol, styrene, and toluene. Additive Mixture Values (AMVs) were calculated using the New Zealand Workplace Exposure standard (WES) and American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) of the 8-h, time-weighted average exposure limit. Linear regression was conducted to assess associations with work characteristics. RESULTS: We included 133 workers handling shipping containers, 15 retail workers unpacking container goods, 40 workers loading fumigated and non-fumigated export logs, and 5 fumigators. A total of 193 personal 8-h air measurements were collected. Exposures were generally low, with >50% below the limit of detection for most chemicals, and none exceeding the NZ WES, although formaldehyde exceeded the TLV in 26.2% of all measurements. The AMV-TLV threshold of 1 was exceeded in 29.0% of the measurements. Levels and detection frequencies of most chemicals varied little between occupational groups, although exposure to methyl bromide was highest in the fumigators (median 43 ppb) without exceeding the TLV of 1000 ppb. Duration spent inside the container was associated with significantly higher levels of ethylene oxide, C2-alkylbenzenes, and acetaldehyde, but levels were well below the TLV/WES. Exposure levels did not differ between workers handling fumigated and non-fumigated containers. CONCLUSIONS: Personal exposures of workers handling container cargo in New Zealand were mainly below current exposure standards, with formaldehyde the main contributor to overall exposure. However, as it is not clear whether working conditions of participants included in this study were representative of this industry as a whole, and not all relevant exposures were measured, we cannot exclude the possibility that high exposures may occur in some workers.

Occupation and motor neuron disease: a New Zealand case-control study.

OBJECTIVES: To assess associations between occupation and motor neuron disease (MND). METHODS: We conducted a population-based case-control study with cases (n=321) recruited through the New Zealand Motor Neurone Disease Association and hospital discharge data. Controls (n=605) were recruited from the Electoral Roll. Information on personal and demographic details, lifestyle factors and a full occupational history was collected using questionnaires and interviews. Associations with ever/never employed and employment duration were estimated using logistic regression stratified by sex and adjusted for age, ethnicity, socioeconomic deprivation, education and smoking. RESULTS: Elevated risks were observed for field crop and vegetable growers (OR 2.93, 95% CI 1.10 to 7.77); fruit growers (OR 2.03, 95% CI 1.09 to 3.78); gardeners and nursery growers (OR 1.96, 95% CI 1.01 to 3.82); crop and livestock producers (OR 3.61, 95% CI 1.44 to 9.02); fishery workers, hunters and trappers (OR 5.62, 95% CI 1.27 to 24.97); builders (OR 2.90, 95% CI 1.41 to 5.96); electricians (OR 3.61, 95% CI 1.34 to 9.74); caregivers (OR 2.65, 95% CI 1.04 to 6.79); forecourt attendants (OR 8.31, 95% CI 1.79 to 38.54); plant and machine operators and assemblers (OR 1.42, 95% CI 1.01 to 2.01); telecommunications technicians (OR 4.2, 95% CI 1.20 to 14.64); and draughting technicians (OR 3.02, 95% CI 1.07 to 8.53). Industries with increased risks were agriculture (particularly horticulture and fruit growing), construction, non-residential care services, motor vehicle retailing, and sport and recreation. Positive associations between employment duration and MND were shown for the occupations fruit growers, gardeners and nursery growers, and crop and livestock producers, and for the horticulture and fruit growing industry. CONCLUSIONS: This study suggests associations between MND and occupations in agriculture and several other occupations.

Determinants of Airborne Solvent Exposure in the Collision Repair Industry.

Objectives: To assess the determinants of airborne solvent exposures in contemporary vehicle collision repair workplaces. Methods: Personal, full-shift airborne solvent exposures (n = 97) were assessed in 85 vehicle collision repair workers from 18 workshops. Peak exposures were assessed using a small number of video exposure monitoring measurements. Results: Solvent exposures were highest in spray painters (geometric mean = 2.7 ppm) followed by panel beaters (0.5 ppm), but were well below workplace exposure standards. The lowest exposure levels were observed for mixing room extraction located away from the mixing bench [exposure ratio (ER) = 0.51, 95% confidence interval (CI) = 0.30-0.87]. Time spent mixing paint was associated with higher exposures (ER for every 10-min increase = 1.14, 95% CI = 1.05-1.24), as was time spent cleaning equipment with solvents (ER = 1.11, 95% CI = 0.88-1.39), spraying primer (ER = 1.10, 95% CI = 0.96-1.27), and spraying clear coat paint (ER = 1.07, 95% CI = 1.00-1.15). Overall, the combined non-spray painting tasks (mixing paint, degreasing, and cleaning equipment) were more strongly associated with exposure (ER = 1.10, 95% CI = 1.03-1.18) than the combined spray painting tasks (ER = 1.03, 95% CI = 1.00-1.05). Peak exposures ranged from 10 to 1100 ppm with the strongest and most frequent peaks occurring during paint mixing, decanting of solvents, cleaning of equipment, and painting in a cross-draft spray booth. Conclusions: Airborne solvent exposures in the collision repair industry were associated with job title, the design and location of exhaust ventilation and emission sources, and time spent on specific tasks, with the highest average and peak exposures shown for non-spray painting tasks. These findings provide a contemporary basis for intervention programmes to reduce airborne solvent exposures in this industry.

Effects of Personal Protective Equipment Use and Good Workplace Hygiene on Symptoms of Neurotoxicity in Solvent-Exposed Vehicle Spray Painters.

Objectives: To assess the association between the use of personal protective equipment (PPE) and good workplace hygiene and symptoms of neurotoxicity in solvent-exposed vehicle spray painters. Methods: Exposure control measures including PPE-use and workplace hygiene practices and symptoms of neurotoxicity were assessed in 267 vehicle repair spray painters. Symptoms were assessed using an adapted version of the EUROQUEST Questionnaire. Results: Frequent respirator and glove use was inversely and significantly associated with symptoms of neurotoxicity in a dose-dependent manner (P < 0.05 for trend) with the strongest protective effect found for consistent glove use (odds ratios [OR] 0.1-0.2, P < 0.01, for reporting ≥10 and ≥5 symptoms). A clear dose-response trend was also observed when combining frequency of respirator and glove use (P < 0.05 for reporting ≥5 and ≥10 symptoms), with an overall reduction in risk of 90% (OR, 0.1, P < 0.01) for those who consistently used both types of PPE. Protective effects were most pronounced for the symptom domains of psychosomatic (P < 0.05 for trend, for combined PPE use), mood (P < 0.05), and memory and concentration symptoms combined (P < 0.05), with reductions in risk of >80%. Poor hygiene workplace practices, such as solvent exposure to multiple body parts (OR 3.4, P = 0.11 for reporting ≥10 symptoms), were associated with an increased risk of symptoms. When using a general workplace hygiene score derived from a combination of PPE-use and (good) workplace practice factors an inverse and significant dose-response trend was observed for reporting ≥5 (P < 0.01) and ≥10 symptoms (P < 0.01). Conclusions: This study has shown that PPE-use and good workplace hygiene are associated with a strongly reduced risk of symptoms of neurotoxicity in solvent-exposed vehicle spray painters.

Exposure to respirable crystalline silica in the construction industry-do we have a problem?

AIMS: To assess personal exposure to respirable dust and respirable crystalline silica (RCS) in New Zealand construction workers. METHODS: In a pilot study, 39 personal samples were collected from a cross-section of workers engaged in a range of tasks performed on construction sites that were expected to entail exposure to respirable crystalline silica. Nine static samples were taken at locations adjacent to these tasks. Particle size-selective sampling heads were used to collect the respirable fraction of airborne particulates. Dust concentrations were determined gravimetrically, while crystalline silica was analysed using x-ray diffraction. RESULTS: Almost half of the personal crystalline silica samples exceeded the New Zealand Workplace Exposure Standard (NZ WES), while 56% exceeded the more stringent international recommendation (ACGIH TLV). The tasks associated with the highest RCS levels were concrete grinding and cutting. Two of four static samples collected close to (silica-containing) Linea board cutting exceeded the ACGIH TLV for RCS, indicating the potential for bystander exposure. CONCLUSIONS: A large proportion of workers performing common tasks in the construction industry may be exposed to levels of respirable dust and crystalline silica exceeding national standards and international recommendations. These results suggest that workers in this industry may be at risk of developing silica-related diseases, including silicosis, lung cancer, COPD and chronic renal disease. Action is required to improve dust control to reduce silica exposure and the associated health risks.

Neuropsychological performance in solvent-exposed vehicle collision repair workers in New Zealand.

OBJECTIVES: To assess whether contemporary solvent exposures in the vehicle collision repair industry are associated with objectively measured neuropsychological performance in collision repair workers. METHODS: The RBANS battery and additional tests were administered to 47 vehicle collision repair and 51 comparison workers randomly selected from a previous questionnaire study. RESULTS: Collision repair workers performed lower on tests of attention (digit span backwards: -1.5, 95% CI -2.4, -0.5; digit span total: -1.7, CI -3.3, -0.0; coding: -6.1, CI -9.9, -2.8; total attention scale: -9.3, CI -15.9, -2.8) and the RBANS total scale (-5.1, CI -9.1, -1.2). Additional tests also showed deficits in visual attention and reaction time (Trails B: -11.5, CI -22.4, -0.5) and motor speed/dexterity (coin rotation dominant hand & non-dominant: -2.9, CI -5.3, -0.4 and -3.1, CI -5.6, -0.7 respectively). The strongest associations were observed in panel beaters. Applying dichotomised RBANS outcomes based on the lowest percentile scores of a normative comparison group showed strongly increased risks for attention (5th percentile: OR 20.1, 95% CI 1.5, 263.3; 10th percentile: 8.8, CI 1.7, 46.2; and 20th percentile: 5.1, CI 1.5, 17.6, respectively). Those employed in the industry for ≤ 17 years (the median work duration) generally had lower scores in the attention domain scale and RBANS total scale compared to those employed >17 years suggesting a healthy worker survivor bias, but trends were inconsistent for other domains. CONCLUSIONS: This study has found significant deficits in cognitive performance in collision repair workers despite low current airborne exposures in New Zealand.

Solvent neurotoxicity in vehicle collision repair workers in New Zealand.

OBJECTIVES: To assess whether solvent use and workplace practices in the vehicle collision repair industry are associated with symptoms of neurotoxicity in spray painters and panel beaters (auto body repair workers). METHODS: Neurobehavioural symptoms were assessed using a cross-sectional study design in 370 vehicle collision repair and 211 reference workers using the EUROQUEST questionnaire. Full-shift airborne solvent levels were measured in a subset (n=92) of collision repair workers. RESULTS: Solvent exposures were higher in spray painters than in panel beaters, but levels were below current international exposure standards. Collision repair workers were more likely to report symptoms of neurotoxicity than reference workers with ORs of 2.0, 2.4 and 6.4 (all p<0.05) for reporting ≥5, ≥10 and ≥15 symptoms respectively. This trend was generally strongest for panel beaters (ORs of 2.1, 3.3 and 8.2 for ≥5, ≥10 and ≥15 symptoms respectively). Associations with specific symptom domains showed increased risks for neurological (OR 4.2), psychosomatic (OR 3.2), mood (OR 2.1), memory (OR 2.9) and memory and concentration symptoms combined (OR 2.4; all p<0.05). Workers who had worked for 10-19 years or 20+ years in the collision repair industry reported consistently more symptoms than those who had only worked less than 10 years even after adjusting for age. However, those who worked more than 20 years generally reported fewer symptoms than those who worked 10-19 years, suggesting a possible healthy worker survivor bias. CONCLUSIONS: Despite low airborne solvent exposures, vehicle collision repair spray painters and panel beaters continue to be at risk of symptoms of neurotoxicity.