Browsing by Author "Hinz, Ruth"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- ItemExposure to fumigants and residual chemicals in workers handling cargo from shipping containers and export logs : a study of exposure determinants and neuropsychological symptoms : a thesis by publications presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Public Health (Epidemiology) at Massey University, Wellington, New Zealand(Massey University, 2022) Hinz, RuthFumigants are widely used in shipping containers and on export logs for biosecurity reasons. This thesis aimed to: (i) assess concentrations of fumigants and off-gassed chemicals in closed containers; (ii) identify container characteristics associated with high concentrations; (iii) assess personal exposure levels of workers exposed to these chemicals; and (iv) assess whether exposed workers report more neuropsychological symptoms. Air samples were collected from 490 sealed containers and at opening of 46 containers, and 193 personal full-shift air samples were collected for 133 container handlers, 15 retail workers, 40 workers loading export logs, and 5 fumigators. Samples were analysed by Selected Ion Flow Tube Mass Spectrometry for several common fumigants and harmful chemicals frequently found in shipping containers. Levels were compared to the New Zealand Work Exposure Standard (WES) and the Threshold Limit Value (TLV). A neuropsychological symptom questionnaire was completed by 274 container handlers, 38 retail workers, 35 fumigators, 18 log workers, and a reference group of 206 construction workers. Fumigants were detected in 11.4% of sealed containers (ethylene oxide 4.7%; methyl bromide 3.5%). Chemicals other than fumigants were detected more frequently, particularly formaldehyde (84.7%). Some cargo types (e.g. rubber products) and countries of origin (e.g. China) were associated with higher chemical concentrations. Fumigants were detected in both fumigated and non-fumigated containers. Ambient chemical concentrations in closed and just opened containers regularly exceeded the NZ WES and TLV. Personal exposure measurements never exceeded the NZ WES, although for 26.2% of samples the TLV for formaldehyde was exceeded. Duration spent unloading containers was associated with higher levels of ethylene oxide, C2-alkylbenzenes and acetaldehyde. Exposed workers were more likely to report ≥10 symptoms, and particularly for the fatigue domain. Longer cumulative duration of unloading containers was associated with more symptoms (Odds Ratio (OR) 7.5, 95% Confidence Interval (CI) 1.7-32.8), and specifically for symptoms in the memory/-concentration domain (OR 6.8, 95%CI 1.5-30.3), when comparing the highest exposure duration tertile to the lowest. In conclusion, while workers’ full-shift exposure levels to container chemicals are lower than previously expected (based on the high levels measured in closed containers), they may nonetheless cause long-term health effects.
- ItemHydrogen sulphide in Rotorua, New Zealand : personal exposure assessment and health effects : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Earth Science at Massey University, Palmerston North, New Zealand(Massey University, 2011) Hinz, Ruth; Hinz, RuthLong-term exposure to low level hydrogen sulphide (H2S) may be a health risk. However, research on this has been scarce. Rotorua offers a unique opportunity for such an investigation as its population is regularly exposed to geothermal H2S and few copollutants are present. To date, only ambient H2S concentrations have been investigated. The current study aimed to measure personal exposure levels and to assess potential health effects. In particular, the study involved: 1. Method development to measure exposure, including the adaption of a personal sampler 2. Analysis of personal exposure levels including personal and ambient air measurements 3. Identification of the main determinants of exposure 4. Assessment of the association between personal exposure and health effects involving the respiratory, the circulatory and the nervous systems. The Chemcassette® tape was found to be a suitable and cost effective personal sampler. More than 75% of participants had exposure levels below 5 parts per billion (ppb). The group of remaining participants had exposure levels between 5 and 90 ppb, which were five times higher than those measured in the other two groups (CI: 3.71-6.73). Those participants had frequented a 1-2 km wide north-south corridor in central Rotorua for longer than 2 hours. Previously, the corridor had been identified as an area of elevated H2S concentrations in geological and ambient air surveys. However personal exposure levels were considerably lower than air monitoring data in this area. Whether this is attributable to the mobility of participants or the sheltering effect of buildings is unclear. Personal samplers with readings above 90 ppb were associated with proximity to geothermal sources and/ or buildings with H2S intrusion. Personal exposure levels varied between trials in the central corridor, while western and eastern Rotorua consistently showed low levels (<5 ppb). Higher H2S concentrations (up to 3.5 times CI 2.07-5.76) in the central corridor were associated with north-north-easterly to easterly winds carrying additional H2S from the Sulphur Bay geothermal area on the eastern margin of the corridor (effect estimate coefficient: 3.5, CI 2.07-5.76). An indication of an increased asthma risk was found for the southern part of the corridor (OR: 2.9, CI: 1.17-7.18), but the association needs further investigation. In conclusion, this study found elevated personal H2S levels along a central corridor in Rotorua and the possibility of an association with asthma.