title: The Status of Iodine and Selenium in Waikato Soils

authors: McNally, Samuel Rae

subjects: Iodine

abstract: This thesis investigates the status of the essential trace elements iodine and selenium in Waikato soils. Soil samples (368) representing different Soil Orders, land uses and soil depths were examined.
A tetramethyl ammonium hydroxide extraction method followed by ICP-MS was validated for iodine determination. This method was suitable for total iodine determination and also gave a reliable estimate of the total selenium content of soils, based on analysis of Certified Reference Materials.
Acid extraction of selenium was unsuitable because of difficulties with recoveries and interferences in the ICP-MS, although the use of methane and DRC-ICP-MS reduced interferences. Time and equipment constraints limited the complete validation using acid extraction for total selenium determination.
Waikato soils had a mean iodine content of 20.9 mg kg-¹, geometric mean of 13.7 mg kg-¹ and range of 1.5 – 122.8 mg kg-¹. Allophanic and Granular soils contained the highest mean iodine contents with Pumice soils displaying the lowest. The iodine content was shown to increase with soil depth, with the Waikato soils showing no evidence of coastal enrichment, though this could be explained by the losses of iodine being equal to, or exceeding the additions to soil. 
Land use appeared to have an effect on the iodine content of soils with background soils displaying more iodine on average than both farmed and forestry soils. Forestry soils displayed the lowest mean iodine content. Farming and forestry both appear to reduce the amount of iodine in soils. 
Iodine was correlated strongly to aluminium and iron, indicating that clay minerals and iron oxides are the most important in the retention of iodine, with organic matter appearing to be less important in iodine retention. There was also a strong correlation of iodine with selenium and mercury, suggesting an association between these elements.
The selenium status of Waikato soils showed a mean concentration of 1.77 mg kg-¹, geometric mean 1.33 mg kg-¹ and a range in concentration of 0.18 – 12.1 mg kg-¹. Like iodine, selenium also displayed the highest mean concentrations in Allophanic and Granular soils, with the lowest concentrations in Pumice soils. The concentration of selenium also increased with soil depth, with parent material appearing to affect the selenium content of soils. Selenium appeared to be more concentrated in the soils closest to the coast than those more inland; with the relative enrichment suggesting that the losses of selenium are likely to equal or exceed the inputs from the surface.
Selenium concentration in relation to land use indicated that farming and forestry may be depleting selenium from soils, with background soils displaying more selenium on average than both farmed and forestry soils.
Again selenium showed similar behaviour to iodine in that it was strongly correlated to aluminium, iron and manganese, indicating that clay minerals and iron and manganese oxides are the most important factors in selenium retention in Waikato soils. Organic matter was less important in retention shown by the less significant correlation with selenium. Mercury and iodine were both strongly correlated to selenium suggesting that chalcophilic elements (mercury) are strongly associated to selenium.
The strong correlation between iodine and selenium also explained the similarities in the relationships of both elements with other soil properties. The results presented for both iodine and selenium indicate that the status of both elements in the Waikato Region may be better than previously thought, with the soils showing mean concentrations that suggest they may not be as deficient as thought.

text: The Status of Iodine and Selenium in Waikato Soils This thesis investigates the status of the essential trace elements iodine and selenium in Waikato soils. Soil samples (368) representing different Soil Orders, land uses and soil depths were examined.
A tetramethyl ammonium hydroxide extraction method followed by ICP-MS was validated for iodine determination. This method was suitable for total iodine determination and also gave a reliable estimate of the total selenium content of soils, based on analysis of Certified Reference Materials.
Acid extraction of selenium was unsuitable because of difficulties with recoveries and interferences in the ICP-MS, although the use of methane and DRC-ICP-MS reduced interferences. Time and equipment constraints limited the complete validation using acid extraction for total selenium determination.
Waikato soils had a mean iodine content of 20.9 mg kg-¹, geometric mean of 13.7 mg kg-¹ and range of 1.5 – 122.8 mg kg-¹. Allophanic and Granular soils contained the highest mean iodine contents with Pumice soils displaying the lowest. The iodine content was shown to increase with soil depth, with the Waikato soils showing no evidence of coastal enrichment, though this could be explained by the losses of iodine being equal to, or exceeding the additions to soil. 
Land use appeared to have an effect on the iodine content of soils with background soils displaying more iodine on average than both farmed and forestry soils. Forestry soils displayed the lowest mean iodine content. Farming and forestry both appear to reduce the amount of iodine in soils. 
Iodine was correlated strongly to aluminium and iron, indicating that clay minerals and iron oxides are the most important in the retention of iodine, with organic matter appearing to be less important in iodine retention. There was also a strong correlation of iodine with selenium and mercury, suggesting an association between these elements.
The selenium status of Waikato soils showed a mean concentration of 1.77 mg kg-¹, geometric mean 1.33 mg kg-¹ and a range in concentration of 0.18 – 12.1 mg kg-¹. Like iodine, selenium also displayed the highest mean concentrations in Allophanic and Granular soils, with the lowest concentrations in Pumice soils. The concentration of selenium also increased with soil depth, with parent material appearing to affect the selenium content of soils. Selenium appeared to be more concentrated in the soils closest to the coast than those more inland; with the relative enrichment suggesting that the losses of selenium are likely to equal or exceed the inputs from the surface.
Selenium concentration in relation to land use indicated that farming and forestry may be depleting selenium from soils, with background soils displaying more selenium on average than both farmed and forestry soils.
Again selenium showed similar behaviour to iodine in that it was strongly correlated to aluminium, iron and manganese, indicating that clay minerals and iron and manganese oxides are the most important factors in selenium retention in Waikato soils. Organic matter was less important in retention shown by the less significant correlation with selenium. Mercury and iodine were both strongly correlated to selenium suggesting that chalcophilic elements (mercury) are strongly associated to selenium.
The strong correlation between iodine and selenium also explained the similarities in the relationships of both elements with other soil properties. The results presented for both iodine and selenium indicate that the status of both elements in the Waikato Region may be better than previously thought, with the soils showing mean concentrations that suggest they may not be as deficient as thought.

year: 2011

title: Network analysis of mindfulness and mental health symptoms among firefighters: A transdiagnostic lens

authors: Yan, Vivienne Yu-X.

abstract: Objectives: Previous research has established the protective role of mindfulness against various psychological disorders and maladaptive behaviours. However, the associations between specific facets of mindfulness and diverse mental health and behavioural outcomes have not been thoroughly investigated in populations with risky occupations. The aim of this study was to examine the direct and indirect associations between the five facets of mindfulness and prevalent mental health and behavioural outcomes among firefighters, including depression, post-traumatic stress disorder (PTSD), anger, suicide risk, sleep quality, and alcohol use. Method: The assessment scores of 685 career firefighters (Mage = 38.40, SD = 8.64; 93.6% males; 77.7% White) including 154 (22.5%) military veterans, who completed measures of mindfulness, depression, PTSD, anger, suicide risk, sleep quality, and alcohol use, were investigated using both directional and non-directional network analysis. Results: Directional network analysis indicated the primary role of anger in triggering PTSD and impacting mindfulness, leading to alcohol use, suicidal ideation, impaired sleep quality, and depression as an outcome. Mindfulness facets of Non-reactivity, Non-judging, and Describing were negatively associated with depression, while the Acting with awareness facet was inversely linked to anger. Conclusion: This study emphasizes the clinical significance of targeting specific mindfulness facets in interventions for high-risk occupations, such as firefighters. Focusing on Non-reactivity, Non-judging, Describing, and Acting with awareness may help mitigate anger, depression, and other negative outcomes. Addressing anger management could be especially important in preventing or reducing PTSD, alcohol use, suicidal ideation, sleep disturbances, and depression, ultimately enhancing psychological well-being and quality of life.

text: Network analysis of mindfulness and mental health symptoms among firefighters: A transdiagnostic lens Objectives: Previous research has established the protective role of mindfulness against various psychological disorders and maladaptive behaviours. However, the associations between specific facets of mindfulness and diverse mental health and behavioural outcomes have not been thoroughly investigated in populations with risky occupations. The aim of this study was to examine the direct and indirect associations between the five facets of mindfulness and prevalent mental health and behavioural outcomes among firefighters, including depression, post-traumatic stress disorder (PTSD), anger, suicide risk, sleep quality, and alcohol use. Method: The assessment scores of 685 career firefighters (Mage = 38.40, SD = 8.64; 93.6% males; 77.7% White) including 154 (22.5%) military veterans, who completed measures of mindfulness, depression, PTSD, anger, suicide risk, sleep quality, and alcohol use, were investigated using both directional and non-directional network analysis. Results: Directional network analysis indicated the primary role of anger in triggering PTSD and impacting mindfulness, leading to alcohol use, suicidal ideation, impaired sleep quality, and depression as an outcome. Mindfulness facets of Non-reactivity, Non-judging, and Describing were negatively associated with depression, while the Acting with awareness facet was inversely linked to anger. Conclusion: This study emphasizes the clinical significance of targeting specific mindfulness facets in interventions for high-risk occupations, such as firefighters. Focusing on Non-reactivity, Non-judging, Describing, and Acting with awareness may help mitigate anger, depression, and other negative outcomes. Addressing anger management could be especially important in preventing or reducing PTSD, alcohol use, suicidal ideation, sleep disturbances, and depression, ultimately enhancing psychological well-being and quality of life.

year: 2024-05-20

title: An evaluation of Te Rau Puawai workforce 100: Perspectives of Te Rau Puawai bursars

authors: Nikora, Linda Waimarie

subjects: Maori students

abstract: The Te Rau Puawai programme is an attempt to change the nature of the Maori
mental health workforce. To do this, Maori with aspirations to work, or to continue to
work in the mental health workforce, are supported, financially and academically, to
complete a tertiary qualification relevant to the field.
To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
The evaluation team set out to gather the experiences and perspectives of recipients of
Te Rau Puawai services by asking all bursars to complete a questionnaire and
volunteer for follow up interviews or focus groups. Sixty two bursars responded to
our questionnaire, and we complete focus group or individual follow up interviews
with 19 bursars.

text: An evaluation of Te Rau Puawai workforce 100: Perspectives of Te Rau Puawai bursars The Te Rau Puawai programme is an attempt to change the nature of the Maori
mental health workforce. To do this, Maori with aspirations to work, or to continue to
work in the mental health workforce, are supported, financially and academically, to
complete a tertiary qualification relevant to the field.
To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
The evaluation team set out to gather the experiences and perspectives of recipients of
Te Rau Puawai services by asking all bursars to complete a questionnaire and
volunteer for follow up interviews or focus groups. Sixty two bursars responded to
our questionnaire, and we complete focus group or individual follow up interviews
with 19 bursars.

year: 2002-05-01