title: Coastal erosion and sedimentation of Pukehina Beach and Waihi Estuary

authors: Easton, Hayden Russell

subjects: Pukehina Beach

abstract: The Pukehina coastal sector is subject to severe frontal dune erosion. This has led to concern from local residents who reside in frontal houses. Accordingly, this investigation was initiated to assess the sedimentary and physical processes within the Pukehina coastal sector, with the aim of identifying causes of enhanced frontal dune erosion.
To investigate this problem the following processes were investigated: wave focusing from offshore bathymetric lenses, sediment lost due to the Waihi Estuary acting as a sediment sink, and/or a change in sediment volume or sediment transport processes within the Pukehina coastal sector. Methods to investigate these processes included: collection and analysis of surficial sediment samples from Pukehina Beach and Waihi Estuary, construction of a digital terrain model, side scan sonar surveying, calculation of offshore suspended sediment concentrations, numerical modelling of wave refraction and sediment transport processes, and collection and analysis of wave and estuarine current, depth, and direction data.
Wave data were collected at eastern and western ends of the study location, during two separate deployments during July 2000 and March 2001. Outcomes depict differing incoming wave directions at each site, due to offshore undulations in bathymetry. Wave energy focusing was observed along the Pukehina coastal sector (specifically at benchmarks 30, 29, 27 and 26a) during average wave conditions recorded, and enhanced as wave period and wave height increased (approximately 0.2-2.0 m in each simulation, respectively). Wave focusing is significantly influenced by the ebb tidal delta offshore from Waihi Estuary, leading to larger wave heights present in eroding regions of Pukehina Beach.
Potential sediment transport rates were investigated, utilising collected wave data. Outcomes illustrate a potential sediment transport to the east. A negative littoral drift gradient, was observed between a) Okurei Point and Waihi Estuary inlet, and a positive littoral drift gradient between b) benchmark 29 and 26. This implies a potential accumulation of sediments near Waihi Estuary inlet (some of which, would be lost to infilling of Waihi Estuary). However, a long-term deficit (-12 m3/m per year) of sediment is lost along Pukehina Beach, due to the apparent positive littoral drift gradient. This outcome is identified as a major component of the long-term 'erosion' problem at Pukehina Beach.
Tidal and current gauges were deployed within Waihi Estuary. Data revealed strong evidence that the estuary is acting as a sediment sink. Tidal asymmetry, attenuation of the tidal signal and a dominance of sediment transport into the estuary, depict that Waihi Estuary is an influential component of the erosion occurring at Pukehina Beach. The Waihi Estuary is calculated by geomorphic and hydraulic analysis to be tending towards deposition in the inlet, leading to a general instability of the Waihi Estuary inlet.
Nearshore sediment transport rates within the region are significantly influenced by localised wind patterns within the Pukehina coastal sector. The Pukehina coastal sector was identified as having a net deficit of sediment, approximately 4,500 m³/year or -0.5 m³/m per year. However, due to errors involved in estimate calculations, this value may be larger.
Sediment textural distributions have altered since previous surveys conducted in 1993 by PHIZACKLEA. Particularly, an influx of sediment to the Okurei Point region, reducing the area of exposed bedrock, suggests a change of sediment transport patterns within this region. Texturally, offshore sediments vary from fine sand sized sediments to very coarse sand, while beach sediments are predominantly medium sand sized particles, with a decrease in sediment size towards Okurei Point (fine sand sized particles), indicating a sediment transport direction to the west.
Causes of significant long-term erosion to the Pukehina coastal sector, have been identified as: a) beach-nearshore sediment being lost or 'sucked out' of the coastal sector, due to the combination of a positive littoral drift gradient along Pukehina Beach, and wave energy focusing; and b) infilling of the Waihi Estuary. Other processes, such as aeolian transport etc., do reduce the volume of available sediment to Pukehina Beach, but are not implicated to the long-term 'erosion' problem occurring.
Possible remedial solutions, influenced by data observations, are suggested to reduce current frontal dune erosion. However, further research is recommended to identify what coastal management options are required for the Pukehina Beach shoreline.

text: Coastal erosion and sedimentation of Pukehina Beach and Waihi Estuary The Pukehina coastal sector is subject to severe frontal dune erosion. This has led to concern from local residents who reside in frontal houses. Accordingly, this investigation was initiated to assess the sedimentary and physical processes within the Pukehina coastal sector, with the aim of identifying causes of enhanced frontal dune erosion.
To investigate this problem the following processes were investigated: wave focusing from offshore bathymetric lenses, sediment lost due to the Waihi Estuary acting as a sediment sink, and/or a change in sediment volume or sediment transport processes within the Pukehina coastal sector. Methods to investigate these processes included: collection and analysis of surficial sediment samples from Pukehina Beach and Waihi Estuary, construction of a digital terrain model, side scan sonar surveying, calculation of offshore suspended sediment concentrations, numerical modelling of wave refraction and sediment transport processes, and collection and analysis of wave and estuarine current, depth, and direction data.
Wave data were collected at eastern and western ends of the study location, during two separate deployments during July 2000 and March 2001. Outcomes depict differing incoming wave directions at each site, due to offshore undulations in bathymetry. Wave energy focusing was observed along the Pukehina coastal sector (specifically at benchmarks 30, 29, 27 and 26a) during average wave conditions recorded, and enhanced as wave period and wave height increased (approximately 0.2-2.0 m in each simulation, respectively). Wave focusing is significantly influenced by the ebb tidal delta offshore from Waihi Estuary, leading to larger wave heights present in eroding regions of Pukehina Beach.
Potential sediment transport rates were investigated, utilising collected wave data. Outcomes illustrate a potential sediment transport to the east. A negative littoral drift gradient, was observed between a) Okurei Point and Waihi Estuary inlet, and a positive littoral drift gradient between b) benchmark 29 and 26. This implies a potential accumulation of sediments near Waihi Estuary inlet (some of which, would be lost to infilling of Waihi Estuary). However, a long-term deficit (-12 m3/m per year) of sediment is lost along Pukehina Beach, due to the apparent positive littoral drift gradient. This outcome is identified as a major component of the long-term 'erosion' problem at Pukehina Beach.
Tidal and current gauges were deployed within Waihi Estuary. Data revealed strong evidence that the estuary is acting as a sediment sink. Tidal asymmetry, attenuation of the tidal signal and a dominance of sediment transport into the estuary, depict that Waihi Estuary is an influential component of the erosion occurring at Pukehina Beach. The Waihi Estuary is calculated by geomorphic and hydraulic analysis to be tending towards deposition in the inlet, leading to a general instability of the Waihi Estuary inlet.
Nearshore sediment transport rates within the region are significantly influenced by localised wind patterns within the Pukehina coastal sector. The Pukehina coastal sector was identified as having a net deficit of sediment, approximately 4,500 m³/year or -0.5 m³/m per year. However, due to errors involved in estimate calculations, this value may be larger.
Sediment textural distributions have altered since previous surveys conducted in 1993 by PHIZACKLEA. Particularly, an influx of sediment to the Okurei Point region, reducing the area of exposed bedrock, suggests a change of sediment transport patterns within this region. Texturally, offshore sediments vary from fine sand sized sediments to very coarse sand, while beach sediments are predominantly medium sand sized particles, with a decrease in sediment size towards Okurei Point (fine sand sized particles), indicating a sediment transport direction to the west.
Causes of significant long-term erosion to the Pukehina coastal sector, have been identified as: a) beach-nearshore sediment being lost or 'sucked out' of the coastal sector, due to the combination of a positive littoral drift gradient along Pukehina Beach, and wave energy focusing; and b) infilling of the Waihi Estuary. Other processes, such as aeolian transport etc., do reduce the volume of available sediment to Pukehina Beach, but are not implicated to the long-term 'erosion' problem occurring.
Possible remedial solutions, influenced by data observations, are suggested to reduce current frontal dune erosion. However, further research is recommended to identify what coastal management options are required for the Pukehina Beach shoreline.

year: 2002

title: Persistence and availability of agrichemical residues in New Zealand horticultural soils

authors: Gaw, S. K.

subjects: Agricultural chemicals Environmental aspects New Zealand

abstract: ﻿New Zealand has a long history of intensive horticulture and many of the greenfield sites designated for residential development have previously been extensively used for horticulture. Currently there is limited information on the potential levels and likely effects of agrichemical residues in horticultural soils available to regulatory authorities with a mandate to manage contaminants in soil. A series of investigations were undertaken to identify the key contaminants present in horticultural soils, to determine the availability and toxicity of contaminants to plants and earthworms, and to estimate likely human exposures to selected contaminants in residential settings. 
Trace element and selected organochlorine pesticide concentrations were measured in soil samples collected from horticultural and grazing properties in three regions of New Zealand (Auckland, Tasman and Waikato). Elevated levels of arsenic ( <2-58 mg kg- 1 ), cadmium (<0.1-1.5 mg kg- 1 ), copper (5-523 mg kg-1), lead (5-243 mg kt1 ) and LDDT (<0.03-34.5 mg kt1 ) were detected in horticultural soils from all three regions. With the exception of cadmium and zinc, significantly higher levels of contaminants were generally detected in horticultural soils than in grazing soils (p<0.05). Concentrations ofLDDT, arsenic, cadmium, copper, and lead in some soils and particularly orchard soils exceeded soil criteria for the protection of ecological receptors and/or human health. Additional analyses undertaken on the Auckland region samples infrequently detected organophosphorus and organonitrogen pesticides and at levels generally less than 1 mg kt1 in horticultural soils. Acidic herbicides were not detected in the Auckland samples. 
p,p '-DDE and p,p '-DDT were the predominant DDT residues measured in horticultural soils. The p,p'-DDE:p,p'-DDT ratios in the measured horticultural soils ranged from 0.4 to 9.7. Significant negative correlations were found between the p,p '-DDE:p,p '-DDT ratios and copper in the Auckland (p<0.001) and Waikato (p<0.02) orchard soils. These results suggest that copper may be a contributing factor to inhibited degradation of p,p'-DDT to p,p'-DDE in orchard soils and that the ratio of p,p '-DDE:p,p '-DDT in horticultural soils, especially orchard soils, should not be used as an indicator ofrecent use ofp,p'-DDT. 
A persulfate oxidation method was used to estimate the fraction of p,p '-DDT in orchard soils available for microbial degradation. The proportion of p,p '-DDT oxidised by the persulfate ranged from 4 to 3 7% indicating that a significant proportion of the p,p '-DDT in the orchard soils (up to 96% in some cases) may not be available for degradation by soil micro-organisms. 
The availability and toxicity of aged LDDT and trace element residues in orchard and grazing soils to the endogenous earthworm Aporrectodea caliginosa (Lumbricidae) was assessed using a 28 day laboratory assay. The worms bioaccumulated the aged DDT residues by up to a factor of 3 with concentrations of LDDT in worm tissue increasing with increasing soil concentration (p<0.001). Worm tissue concentrations ofLDDT correlated with the amount ofLDDT desorbed from soil by two biomimetic extraction techniques, Tenax resin and C-18 disks, indicating that these methods may be suitable for determining the availability of aged LDDT residues to A. caliginosa. Concentrations of arsenic, copper and lead in worm tissue increased with increasing soil concentration of these trace elements (p<0.01). Cocoon production decreased with increasing soil and earthworm tissue copper concentrations (p<0.05). 
A glasshouse study was undertaken to assess uptake of LDDT, arsenic, cadmium, copper and lead into lettuce (Lactuca sativa) and radish (Raphanus sativus) from 10 soils containing typical contaminant concentrations. LDDT concentrations in the assayed soils ranged from 0.02 to 12 mg kg· 1 • The maximum plant tissue LDDT concentrations (DW) followed the order radish hypocotyl (190 µg kg- 1 ) >radish leaf (77 µg kg- 1 ) >lettuce (28 µg kg-1 ) and there were significant correlations between all plant tissue types and the soil concentrationofLDDT andp,p'-DDE (p<0.01). 
Concentrations of cadmium, copper, lead and zinc in lettuce, copper in radish hypocotyls, and copper and zinc in radish leaves increased with increasing soil trace element concentration (p<0.02). Lettuce cadmium concentrations for plants grown on four out of ten assayed soils were equivalent to or exceeded the NZ food standard for leafy vegetables of 0.1 mg kg"1 FW. Lead concentrations in radish hypocotyls grown in three out of eight soils were equivalent to or exceeded half of the NZ food standard for lead in root vegetables of 0.1 mg kg·1 FW. Phytotoxicity was determined by measuring the dry mass yield of lettuce and radish, and by a five day seedling emergence and root elongation assay for lettuce and ryegrass (Lolium perenne). The radish leaf yield and the root length of lettuce seedlings grown in orchard soils for five days decreased with increasing soil copper concentration (total and/or neutral salt extractable). 
A simulated gastric extraction method was used to determine the bioaccessible fraction of arsenic, cadmium and lead in soil. The maximum percent bioaccessible fraction for the trace elements followed the order arsenic (45%)<lead (83%)<cadmium(100%). Likely human exposures to LDDT, arsenic, cadmium and lead in residential settings under two home grown produce consumption scenarios (10 and 50%) were estimated using methodology generally consistent with current NZ government policy. 
Estimated daily intakes of LDDT, arsenic, cadmium and lead for lifetime exposures in residential settings did not exceed the WHO tolerable intakes under the 10% homegrown produce scenario. Similarly, the estimated LDDT and arsenic intakes for the 50% homegrown produce scenario did not exceed their respective WHO tolerable intakes. Estimated cadmium daily intakes for the 50% home grown produce consumption scenario exceeded the WHO tolerable intake for cadmium at soil concentrations greater than 0.75 mg kg- 1 for a child and 1 mg kt1 for the lifetime exposure. Estimated child lead intakes exceeded the WHO tolerable intake at soil concentrations greater than 450 mg kg- 1.
The results presented in this thesis have implications for on going applications of agrichemicals and soil amendments to horticultural land as well as residential subdivision of former horticultural land. Trace element concentrations on some· properties have already reached concentrations where negative effects on terrestrial organisms have been demonstrated to occur. The results in this thesis suggest that a precautionary approach should be adopted to subdividing former horticultural sites. Horticultural land being subdivided in particular for lifestyle blocks should be assessed prior to subdivision to ensure that thresholds for acceptable human exposures are not exceeded.

text: Persistence and availability of agrichemical residues in New Zealand horticultural soils ﻿New Zealand has a long history of intensive horticulture and many of the greenfield sites designated for residential development have previously been extensively used for horticulture. Currently there is limited information on the potential levels and likely effects of agrichemical residues in horticultural soils available to regulatory authorities with a mandate to manage contaminants in soil. A series of investigations were undertaken to identify the key contaminants present in horticultural soils, to determine the availability and toxicity of contaminants to plants and earthworms, and to estimate likely human exposures to selected contaminants in residential settings. 
Trace element and selected organochlorine pesticide concentrations were measured in soil samples collected from horticultural and grazing properties in three regions of New Zealand (Auckland, Tasman and Waikato). Elevated levels of arsenic ( <2-58 mg kg- 1 ), cadmium (<0.1-1.5 mg kg- 1 ), copper (5-523 mg kg-1), lead (5-243 mg kt1 ) and LDDT (<0.03-34.5 mg kt1 ) were detected in horticultural soils from all three regions. With the exception of cadmium and zinc, significantly higher levels of contaminants were generally detected in horticultural soils than in grazing soils (p<0.05). Concentrations ofLDDT, arsenic, cadmium, copper, and lead in some soils and particularly orchard soils exceeded soil criteria for the protection of ecological receptors and/or human health. Additional analyses undertaken on the Auckland region samples infrequently detected organophosphorus and organonitrogen pesticides and at levels generally less than 1 mg kt1 in horticultural soils. Acidic herbicides were not detected in the Auckland samples. 
p,p '-DDE and p,p '-DDT were the predominant DDT residues measured in horticultural soils. The p,p'-DDE:p,p'-DDT ratios in the measured horticultural soils ranged from 0.4 to 9.7. Significant negative correlations were found between the p,p '-DDE:p,p '-DDT ratios and copper in the Auckland (p<0.001) and Waikato (p<0.02) orchard soils. These results suggest that copper may be a contributing factor to inhibited degradation of p,p'-DDT to p,p'-DDE in orchard soils and that the ratio of p,p '-DDE:p,p '-DDT in horticultural soils, especially orchard soils, should not be used as an indicator ofrecent use ofp,p'-DDT. 
A persulfate oxidation method was used to estimate the fraction of p,p '-DDT in orchard soils available for microbial degradation. The proportion of p,p '-DDT oxidised by the persulfate ranged from 4 to 3 7% indicating that a significant proportion of the p,p '-DDT in the orchard soils (up to 96% in some cases) may not be available for degradation by soil micro-organisms. 
The availability and toxicity of aged LDDT and trace element residues in orchard and grazing soils to the endogenous earthworm Aporrectodea caliginosa (Lumbricidae) was assessed using a 28 day laboratory assay. The worms bioaccumulated the aged DDT residues by up to a factor of 3 with concentrations of LDDT in worm tissue increasing with increasing soil concentration (p<0.001). Worm tissue concentrations ofLDDT correlated with the amount ofLDDT desorbed from soil by two biomimetic extraction techniques, Tenax resin and C-18 disks, indicating that these methods may be suitable for determining the availability of aged LDDT residues to A. caliginosa. Concentrations of arsenic, copper and lead in worm tissue increased with increasing soil concentration of these trace elements (p<0.01). Cocoon production decreased with increasing soil and earthworm tissue copper concentrations (p<0.05). 
A glasshouse study was undertaken to assess uptake of LDDT, arsenic, cadmium, copper and lead into lettuce (Lactuca sativa) and radish (Raphanus sativus) from 10 soils containing typical contaminant concentrations. LDDT concentrations in the assayed soils ranged from 0.02 to 12 mg kg· 1 • The maximum plant tissue LDDT concentrations (DW) followed the order radish hypocotyl (190 µg kg- 1 ) >radish leaf (77 µg kg- 1 ) >lettuce (28 µg kg-1 ) and there were significant correlations between all plant tissue types and the soil concentrationofLDDT andp,p'-DDE (p<0.01). 
Concentrations of cadmium, copper, lead and zinc in lettuce, copper in radish hypocotyls, and copper and zinc in radish leaves increased with increasing soil trace element concentration (p<0.02). Lettuce cadmium concentrations for plants grown on four out of ten assayed soils were equivalent to or exceeded the NZ food standard for leafy vegetables of 0.1 mg kg"1 FW. Lead concentrations in radish hypocotyls grown in three out of eight soils were equivalent to or exceeded half of the NZ food standard for lead in root vegetables of 0.1 mg kg·1 FW. Phytotoxicity was determined by measuring the dry mass yield of lettuce and radish, and by a five day seedling emergence and root elongation assay for lettuce and ryegrass (Lolium perenne). The radish leaf yield and the root length of lettuce seedlings grown in orchard soils for five days decreased with increasing soil copper concentration (total and/or neutral salt extractable). 
A simulated gastric extraction method was used to determine the bioaccessible fraction of arsenic, cadmium and lead in soil. The maximum percent bioaccessible fraction for the trace elements followed the order arsenic (45%)<lead (83%)<cadmium(100%). Likely human exposures to LDDT, arsenic, cadmium and lead in residential settings under two home grown produce consumption scenarios (10 and 50%) were estimated using methodology generally consistent with current NZ government policy. 
Estimated daily intakes of LDDT, arsenic, cadmium and lead for lifetime exposures in residential settings did not exceed the WHO tolerable intakes under the 10% homegrown produce scenario. Similarly, the estimated LDDT and arsenic intakes for the 50% homegrown produce scenario did not exceed their respective WHO tolerable intakes. Estimated cadmium daily intakes for the 50% home grown produce consumption scenario exceeded the WHO tolerable intake for cadmium at soil concentrations greater than 0.75 mg kg- 1 for a child and 1 mg kt1 for the lifetime exposure. Estimated child lead intakes exceeded the WHO tolerable intake at soil concentrations greater than 450 mg kg- 1.
The results presented in this thesis have implications for on going applications of agrichemicals and soil amendments to horticultural land as well as residential subdivision of former horticultural land. Trace element concentrations on some· properties have already reached concentrations where negative effects on terrestrial organisms have been demonstrated to occur. The results in this thesis suggest that a precautionary approach should be adopted to subdividing former horticultural sites. Horticultural land being subdivided in particular for lifestyle blocks should be assessed prior to subdivision to ensure that thresholds for acceptable human exposures are not exceeded.

year: 2006

title: Co-opting or valuing the indigenous voice through translation? A decision for research teams

authors: Kidd, Jacquie

subjects: Māori

abstract: Although te reo Māori is an official language of Aotearoa New Zealand, translation of research material such as information sheets, consent forms and questionnaires into te reo Māori remains highly variable. Translation tends to occur in research projects where Māori lead the work and that exclusively focus on Māori communities and topics. Translations are not offered or undertaken as a matter of course for all research. As a team of Māori and Indigenous researchers working within the health sector, we believe that there are important questions that need to be explored around the practice of using Indigenous languages, rich in similes and metaphors, to convey English/Western concepts/constructs/ideologies. In this paper, we draw on the story of one project to deconstruct and challenge the hegemonic terms through which translation of research material occurs. We explore the messages that translated material sends to potential research participants.
We contend that the choice about whether to translate research material into te reo Māori is one that should be undertaken within a robust decision-making framework that considers the reasons for a translation and its impact on the participants. Translation should not be undertaken primarily to attract Māori participants, but should reliably signal that the research is being undertaken in a way that honours a Māori worldview.

text: Co-opting or valuing the indigenous voice through translation? A decision for research teams Although te reo Māori is an official language of Aotearoa New Zealand, translation of research material such as information sheets, consent forms and questionnaires into te reo Māori remains highly variable. Translation tends to occur in research projects where Māori lead the work and that exclusively focus on Māori communities and topics. Translations are not offered or undertaken as a matter of course for all research. As a team of Māori and Indigenous researchers working within the health sector, we believe that there are important questions that need to be explored around the practice of using Indigenous languages, rich in similes and metaphors, to convey English/Western concepts/constructs/ideologies. In this paper, we draw on the story of one project to deconstruct and challenge the hegemonic terms through which translation of research material occurs. We explore the messages that translated material sends to potential research participants.
We contend that the choice about whether to translate research material into te reo Māori is one that should be undertaken within a robust decision-making framework that considers the reasons for a translation and its impact on the participants. Translation should not be undertaken primarily to attract Māori participants, but should reliably signal that the research is being undertaken in a way that honours a Māori worldview.

year: 2019