title: Denitrification and availability of carbon and nitrogen in a well-drained pasture soil amended with particulate organic carbon

authors: Stevenson, Bryan A.

subjects: particulate organic carbon

abstract: A well-drained soil in N-fertilized dairy pasture was amended with particulate organic carbon (POC), either sawdust or coarse woody mulch, and sampled every 4 wk for a year to test the hypothesis that the addition of POC would increase denitrification activity by increasing the number of microsites where denitrification occurred. Overall mean denitrifying enzyme activity (DEA), on a gravimetric basis, was 100% greater for the woody mulch treatment and 50% greater for the sawdust treatment compared with controls, indicating the denitrifying potential of the soil was enhanced. Despite differences in DEA, no difference in denitrification rate, as measured by the acetylene block technique, was detected among treatments, with an average annual N loss of ∼22 kg N ha⁻¹ yr⁻¹ Soil water content overall was driving denitrification in this well-drained soil as regression of the natural log of volumetric soil water content (VWC) against denitrification rate was highly significant (r ² = 0.74, P < 0.001). Addition of the amendments, however, had significant effects on the availability of both C and N. An additional 20 to 40 kg N ha⁻¹ was stored in POC-amended treatments as a result of increases in the microbial biomass. Basal respiration, as a measure of available C, was 400% greater than controls in the sawdust treatment and 250% greater than controls in the mulch. Net N mineralization, however, was significantly lower in the sawdust treatment, resulting in significantly lower nitrate N levels than in the control. We attribute the lack of measured response in denitrification rate to the high temporal variability in denitrification and suggest that diffusion of nitrate may ultimately have limited denitrification in the amended treatments. Our data indicate that manipulation of denitrification by addition of POC may be possible, particularly when nitrate levels are high, but quantifying differences in the rate of denitrification is difficult because of the temporal nature of the process (particularly the complex interaction of N availability and soil water content).

text: Denitrification and availability of carbon and nitrogen in a well-drained pasture soil amended with particulate organic carbon A well-drained soil in N-fertilized dairy pasture was amended with particulate organic carbon (POC), either sawdust or coarse woody mulch, and sampled every 4 wk for a year to test the hypothesis that the addition of POC would increase denitrification activity by increasing the number of microsites where denitrification occurred. Overall mean denitrifying enzyme activity (DEA), on a gravimetric basis, was 100% greater for the woody mulch treatment and 50% greater for the sawdust treatment compared with controls, indicating the denitrifying potential of the soil was enhanced. Despite differences in DEA, no difference in denitrification rate, as measured by the acetylene block technique, was detected among treatments, with an average annual N loss of ∼22 kg N ha⁻¹ yr⁻¹ Soil water content overall was driving denitrification in this well-drained soil as regression of the natural log of volumetric soil water content (VWC) against denitrification rate was highly significant (r ² = 0.74, P < 0.001). Addition of the amendments, however, had significant effects on the availability of both C and N. An additional 20 to 40 kg N ha⁻¹ was stored in POC-amended treatments as a result of increases in the microbial biomass. Basal respiration, as a measure of available C, was 400% greater than controls in the sawdust treatment and 250% greater than controls in the mulch. Net N mineralization, however, was significantly lower in the sawdust treatment, resulting in significantly lower nitrate N levels than in the control. We attribute the lack of measured response in denitrification rate to the high temporal variability in denitrification and suggest that diffusion of nitrate may ultimately have limited denitrification in the amended treatments. Our data indicate that manipulation of denitrification by addition of POC may be possible, particularly when nitrate levels are high, but quantifying differences in the rate of denitrification is difficult because of the temporal nature of the process (particularly the complex interaction of N availability and soil water content).

year: 2011

title: Studies of Leaching of Metals from Food Ceramics

authors: Velayudhan, Prajusha Veethampulli

abstract: In this study the leaching potential of food ceramic wares available in New Zealand has been done using ICP-MS analysis. A survey of ceramic wares purchased in New Zealand markets ranging from historical (antique) Victorian eras (Wilemen bone china and Chapman), mid - 20th century (Alfred Meakin), 1960-1980’s New Zealand-made (Crown Lynn) and modern day ceramic wares manufactured in China, India and Thailand was carried out with respect to their elemental compositions, ceramic composition and leaching potential. All these ceramic wares were found to contain various amounts of heavy metals in their glazes used for imparting special colours, texture and smooth finishes.  
Structural characterisation of these ceramic wares was carried out using different techniques such as solid state magic angle spinning NMR, Fourier transform infrared (FTIR), scanning electron microscopy (SEM) coupled to energy dispersive X-ray analysis (EDX), and X-ray fluorescence (XRF) to determine which elements were present in the bulk of ceramics clay sourced-body and in the glazes. The results of the XRF analysis informed the inductively coupled plasma mass spectroscopy (ICP-MS) studies by providing a list of elements to follow. In general XRF identified a number of heavy metals of interest in all the ceramic wares such as lead and cadmium in Victorian era Wileman and Chapman, mid-20th century Alfred Meakin and especially in the Crown Lynn wares. Barium was predominantly the heavy metal of interest in all modern ceramic wares that are predominantly used by many people in New Zealand. Cobalt, chromium, tin and zinc were present in all the ceramic wares. However, cadmium was significantly present in  the red coloured modern ceramic wares.
These ceramic wares were subjected to leaching tests to detect whether various elements of relevance such as lead, cadmium, barium, cobalt and chromium migrated to any great extent into liquids exposed to these ceramic wares. Leaching studies were done following the ASTM 738 -94 standard test methods for specific metals leaching into 4% acetic acid solutions after a 24 hour exposure time. The lead leached from Victorian era Wileman bone chinaware studied with 4% acetic acid leaching solution was found to exceed the standard safe limits of lead as given by  the FDA (3 µg/mL) and European Council Directive 84/500/EC (4mg/L). The Victorian era Chapman and the New Zealand made Crown Lynn ceramic wares leached lead with 4% acetic acid leaching solution but was below the standard safe limit. However, the modern day ceramic wares manufactured in China, India and Thailand analysed in this research were found to leach extremely low levels of barium being well below the oral reference dose (RFD) for barium given by the US Environmental protection agency (EPA) as 0.07 mg/kg/day, i.e. 4 mg/person/day.
Ceramic teacups were exposed to other leachate solutions based on the normal domestic use and all the leachate solutions were analysed with ICP-MS. These leachate solutions which were exposed to the ceramic teacups for a ten minutes leaching test included: orange juice at room temperature, hot tea at 80 - 95 oC, hot water at 80 - 95 o C, cold water at 4 oC and Coca Cola at room temperature in which some of the Crown Lynn teacups studied were found to be continuously leaching lead in all the tested solutions at varying conditions i.e. pH of the leaching solutions, its temperature and duration of exposure to the leaching solution have influence in migrating the metals from these ceramic teacups tested. However, the level of lead leached from these ceramic teacups was well below the standard safe limits of lead leached from ceramic wares.

text: Studies of Leaching of Metals from Food Ceramics In this study the leaching potential of food ceramic wares available in New Zealand has been done using ICP-MS analysis. A survey of ceramic wares purchased in New Zealand markets ranging from historical (antique) Victorian eras (Wilemen bone china and Chapman), mid - 20th century (Alfred Meakin), 1960-1980’s New Zealand-made (Crown Lynn) and modern day ceramic wares manufactured in China, India and Thailand was carried out with respect to their elemental compositions, ceramic composition and leaching potential. All these ceramic wares were found to contain various amounts of heavy metals in their glazes used for imparting special colours, texture and smooth finishes.  
Structural characterisation of these ceramic wares was carried out using different techniques such as solid state magic angle spinning NMR, Fourier transform infrared (FTIR), scanning electron microscopy (SEM) coupled to energy dispersive X-ray analysis (EDX), and X-ray fluorescence (XRF) to determine which elements were present in the bulk of ceramics clay sourced-body and in the glazes. The results of the XRF analysis informed the inductively coupled plasma mass spectroscopy (ICP-MS) studies by providing a list of elements to follow. In general XRF identified a number of heavy metals of interest in all the ceramic wares such as lead and cadmium in Victorian era Wileman and Chapman, mid-20th century Alfred Meakin and especially in the Crown Lynn wares. Barium was predominantly the heavy metal of interest in all modern ceramic wares that are predominantly used by many people in New Zealand. Cobalt, chromium, tin and zinc were present in all the ceramic wares. However, cadmium was significantly present in  the red coloured modern ceramic wares.
These ceramic wares were subjected to leaching tests to detect whether various elements of relevance such as lead, cadmium, barium, cobalt and chromium migrated to any great extent into liquids exposed to these ceramic wares. Leaching studies were done following the ASTM 738 -94 standard test methods for specific metals leaching into 4% acetic acid solutions after a 24 hour exposure time. The lead leached from Victorian era Wileman bone chinaware studied with 4% acetic acid leaching solution was found to exceed the standard safe limits of lead as given by  the FDA (3 µg/mL) and European Council Directive 84/500/EC (4mg/L). The Victorian era Chapman and the New Zealand made Crown Lynn ceramic wares leached lead with 4% acetic acid leaching solution but was below the standard safe limit. However, the modern day ceramic wares manufactured in China, India and Thailand analysed in this research were found to leach extremely low levels of barium being well below the oral reference dose (RFD) for barium given by the US Environmental protection agency (EPA) as 0.07 mg/kg/day, i.e. 4 mg/person/day.
Ceramic teacups were exposed to other leachate solutions based on the normal domestic use and all the leachate solutions were analysed with ICP-MS. These leachate solutions which were exposed to the ceramic teacups for a ten minutes leaching test included: orange juice at room temperature, hot tea at 80 - 95 oC, hot water at 80 - 95 o C, cold water at 4 oC and Coca Cola at room temperature in which some of the Crown Lynn teacups studied were found to be continuously leaching lead in all the tested solutions at varying conditions i.e. pH of the leaching solutions, its temperature and duration of exposure to the leaching solution have influence in migrating the metals from these ceramic teacups tested. However, the level of lead leached from these ceramic teacups was well below the standard safe limits of lead leached from ceramic wares.

year: 2013

title: Whānau Māori explain how the Harti Hauora Tamariki tool assists better access to health services

authors: Masters-Awatere, Bridgette

abstract: In this paper whānau Māori highlight how a Kaupapa Māori centred intervention (the Harti Hauora Tamariki tool) has improved interactions with health services. The Harti tool is undergoing a Randomised Control Trial at Waikato Hospital in New Zealand. As part of the RCT, the authors engaged in a series of qualitative interviews with whānau members of tamariki Māori (children aged 0-5years) admitted to Waikato Hospital’s paediatric ward. Whānau who met at least one criteria for New Zealand’s domains of deprivation were included. Using a Kaupapa Māori approach to the study, participants shared their views on barriers and facilitators to accessing health resources and primary care services. Our interviews highlight how the Harti tool, when administered in a culturally appropriate and respectful manner that prioritised relationship-building, enabled better connection to healthcare services. Prevalent in our analysis were connections to wider determinants of health and ways to reduce existing health inequities. To conclude the paper, we highlight how the tool has enhanced feelings of being in control of health with the potential to reduce the likelihood of a hospital readmission.

text: Whānau Māori explain how the Harti Hauora Tamariki tool assists better access to health services In this paper whānau Māori highlight how a Kaupapa Māori centred intervention (the Harti Hauora Tamariki tool) has improved interactions with health services. The Harti tool is undergoing a Randomised Control Trial at Waikato Hospital in New Zealand. As part of the RCT, the authors engaged in a series of qualitative interviews with whānau members of tamariki Māori (children aged 0-5years) admitted to Waikato Hospital’s paediatric ward. Whānau who met at least one criteria for New Zealand’s domains of deprivation were included. Using a Kaupapa Māori approach to the study, participants shared their views on barriers and facilitators to accessing health resources and primary care services. Our interviews highlight how the Harti tool, when administered in a culturally appropriate and respectful manner that prioritised relationship-building, enabled better connection to healthcare services. Prevalent in our analysis were connections to wider determinants of health and ways to reduce existing health inequities. To conclude the paper, we highlight how the tool has enhanced feelings of being in control of health with the potential to reduce the likelihood of a hospital readmission.

year: 2019