title: Heavy Metal Contamination from Landfills in Coastal Marine Sediments:  Kiribati and New Zealand.

authors: Redfern, Farran Mack

subjects: Landfill leachate

abstract: Landfill leachates are a concern in the Pacific Region where they may contribute contaminants to the coastal marine environment.  Poor waste management and pollution of coastal waters are amongst the major environmental problems in Kiribati, particularly in South Tarawa.  An investigation of areas adjacent to coastal landfill sites; Betio, Kiribati and Auckland, New Zealand was undertaken.  The Kiribati case study investigated metal contamination in marine sediments at an operational landfill while the New Zealand study was adjacent to a coastal landfill decommissioned in the 1970s. Surficial sediments (top 15 cm) were collected along transects.  At both the New Zealand and Kiribati sites, 3 transects adjacent to the landfill and 1 control transect were sampled.  The sediments were analyzed for particle size distribution, organic matter content, and Cd, As, Cr, Cu, Pb, Hg, Ni and Zn concentrations.  The pH was also measured.

The Kiribati study site had a groundwater pH of 7.14 - 8.85, and sediment materials were dominated by sand with a low organic matter content (1.60 - 2.21 %). At the Kiribati sites Cd, As, and Ni were below the detection limits.  The Cr, Cu, Pb and Zn concentrations were lower at the Kiribati control transect than the landfill transects.  Cr level decreased away from the landfill indicating the landfill as a possible source.  However, Cu and Zn did not show any distribution pattern suggesting other potential sources (port and shipwrecks) may have contributed to the elevated levels.  At the Kiribati landfill and control transects the Cr, As, Cd, Cu, Pb, Ni, and Zn concentration were below the Effects Range-Low (ERL) and the threshold Effects levels (TEL) of the Sediment Quality Guidelines (SQCs) of the National Oceanographic and Atmospheric Administration (NOAA) and the Florida Department of Environmental Protection, indicating no potential adverse ecological effects on the biota.  At the Kiribati control site the Cr, As, Cd, Cu, Pb, Ni and Zn concentrations were within the background ranges published for clean reef sediment but the concentration at the landfill transects exceeded the background ranges. The concentration of mercury at both the control and landfill transects in Kiribati exceeded the Effects Range-Median (ERM) and the Probable Effects Level (PEL) of the SQGs indicating potential adverse ecological effects on the local benthic communities.

The New Zealand study site sediments had a pH of 6.22 - 7.24, and comprised up to 90 % clay/silt, with an organic matter content of 5 - 22 %.  At the New Zealand landfill transects Arsenic concentrations decreased away from the landfill indicating the landfill as a possible source.  Other metals such as Cr did not show a pattern of distribution along the transects, or with depth, suggesting that the landfill was not the only source of these metals.  There was a weak correlation between organic matter content, particle size distribution, and metal enrichment.

At the New Zealand site, there were no marked differences in metal concentrations between the landfill and control transects suggesting the landfill was not the only source of metals and that the wider urban or industrial run-off may have contributed.  All the metal concentrations, except Hg and Zn, exceeded the ERL and the TEL values indicating the potential for adverse ecological effects of metals on the benthic communities.  At the New Zealand site the Hg and Zn concentrations exceeded both the ERM and PEL of the SQGs and are considered highly contaminated.

text: Heavy Metal Contamination from Landfills in Coastal Marine Sediments:  Kiribati and New Zealand. Landfill leachates are a concern in the Pacific Region where they may contribute contaminants to the coastal marine environment.  Poor waste management and pollution of coastal waters are amongst the major environmental problems in Kiribati, particularly in South Tarawa.  An investigation of areas adjacent to coastal landfill sites; Betio, Kiribati and Auckland, New Zealand was undertaken.  The Kiribati case study investigated metal contamination in marine sediments at an operational landfill while the New Zealand study was adjacent to a coastal landfill decommissioned in the 1970s. Surficial sediments (top 15 cm) were collected along transects.  At both the New Zealand and Kiribati sites, 3 transects adjacent to the landfill and 1 control transect were sampled.  The sediments were analyzed for particle size distribution, organic matter content, and Cd, As, Cr, Cu, Pb, Hg, Ni and Zn concentrations.  The pH was also measured.

The Kiribati study site had a groundwater pH of 7.14 - 8.85, and sediment materials were dominated by sand with a low organic matter content (1.60 - 2.21 %). At the Kiribati sites Cd, As, and Ni were below the detection limits.  The Cr, Cu, Pb and Zn concentrations were lower at the Kiribati control transect than the landfill transects.  Cr level decreased away from the landfill indicating the landfill as a possible source.  However, Cu and Zn did not show any distribution pattern suggesting other potential sources (port and shipwrecks) may have contributed to the elevated levels.  At the Kiribati landfill and control transects the Cr, As, Cd, Cu, Pb, Ni, and Zn concentration were below the Effects Range-Low (ERL) and the threshold Effects levels (TEL) of the Sediment Quality Guidelines (SQCs) of the National Oceanographic and Atmospheric Administration (NOAA) and the Florida Department of Environmental Protection, indicating no potential adverse ecological effects on the biota.  At the Kiribati control site the Cr, As, Cd, Cu, Pb, Ni and Zn concentrations were within the background ranges published for clean reef sediment but the concentration at the landfill transects exceeded the background ranges. The concentration of mercury at both the control and landfill transects in Kiribati exceeded the Effects Range-Median (ERM) and the Probable Effects Level (PEL) of the SQGs indicating potential adverse ecological effects on the local benthic communities.

The New Zealand study site sediments had a pH of 6.22 - 7.24, and comprised up to 90 % clay/silt, with an organic matter content of 5 - 22 %.  At the New Zealand landfill transects Arsenic concentrations decreased away from the landfill indicating the landfill as a possible source.  Other metals such as Cr did not show a pattern of distribution along the transects, or with depth, suggesting that the landfill was not the only source of these metals.  There was a weak correlation between organic matter content, particle size distribution, and metal enrichment.

At the New Zealand site, there were no marked differences in metal concentrations between the landfill and control transects suggesting the landfill was not the only source of metals and that the wider urban or industrial run-off may have contributed.  All the metal concentrations, except Hg and Zn, exceeded the ERL and the TEL values indicating the potential for adverse ecological effects of metals on the benthic communities.  At the New Zealand site the Hg and Zn concentrations exceeded both the ERM and PEL of the SQGs and are considered highly contaminated.

year: 2006

title: Reference and current Trophic Level Index of New Zealand lakes: benchmarks to inform lake management and assessment

authors: Abell, Jonathan Michael

subjects: Science & technology

abstract: Knowledge of trophic status is fundamental to understanding the condition and function of lake ecosystems. We developed regression models to predict chlorophyll a concentrations (chl a) in New Zealand lakes for reference and current states, based on an existing dataset of total nitrogen (TN) and total phosphorus (TP) concentrations for 1031 lakes. Models were then developed to predict Secchi depth based on chl a and a sediment resuspension term applicable to shallow lakes. Estimates of all four Trophic Level Index (TLI) variables (chl a, TN, TP and Secchi depth) were analysed to estimate reference and current state TLI for the nationally representative sample of 1031 lakes. There was a trend of eutrophication between reference and current states, with systematic differences among lake geomorphic types. Mean chl a increased 3.5-fold (2.42 mg m­¯­­­³ vs. 8.32 mg m¯³) and mean Secchi depth decreased (indicating lower clarity) by approximately one-third (9.62 m vs. 6.48 m) between reference and current states. On average, TLI increased by 0.67, with the TLI increase >1 in approximately one-third (31%) of lakes. This study informs the status of lake ecosystems in NZ and provides benchmarks to guide management and assessment.

text: Reference and current Trophic Level Index of New Zealand lakes: benchmarks to inform lake management and assessment Knowledge of trophic status is fundamental to understanding the condition and function of lake ecosystems. We developed regression models to predict chlorophyll a concentrations (chl a) in New Zealand lakes for reference and current states, based on an existing dataset of total nitrogen (TN) and total phosphorus (TP) concentrations for 1031 lakes. Models were then developed to predict Secchi depth based on chl a and a sediment resuspension term applicable to shallow lakes. Estimates of all four Trophic Level Index (TLI) variables (chl a, TN, TP and Secchi depth) were analysed to estimate reference and current state TLI for the nationally representative sample of 1031 lakes. There was a trend of eutrophication between reference and current states, with systematic differences among lake geomorphic types. Mean chl a increased 3.5-fold (2.42 mg m­¯­­­³ vs. 8.32 mg m¯³) and mean Secchi depth decreased (indicating lower clarity) by approximately one-third (9.62 m vs. 6.48 m) between reference and current states. On average, TLI increased by 0.67, with the TLI increase >1 in approximately one-third (31%) of lakes. This study informs the status of lake ecosystems in NZ and provides benchmarks to guide management and assessment.

year: 2020

title: Te Whiuwhiu o te Hau Maori Counselling Certificate Programme: Agency placements and supervision. Summary of and evaluation

authors: Moeke-Pickering, Taima Materangatira

subjects: counselling

abstract: Three major characteristics in determining a potentially successful practicum were identified. Firstly, the importance of determining early on whether an agency can expose the student to the necessary counselling experience that enables students to meet the requirements of the course. Secondly, the importance of exposing students to information that enable them to efficiently achieve practicum placement goals. Thirdly, the need to utilise both reflective and skills based assessment to assess the development of counselling skills, as well as the completion of tasks and duties that are required of students. Further information was gleaned about the research participants' perspectives on supervision procedures, practicum contracts, benefits of having a practicum placement and suggested training areas for the proposed TWH supervision module.

text: Te Whiuwhiu o te Hau Maori Counselling Certificate Programme: Agency placements and supervision. Summary of and evaluation Three major characteristics in determining a potentially successful practicum were identified. Firstly, the importance of determining early on whether an agency can expose the student to the necessary counselling experience that enables students to meet the requirements of the course. Secondly, the importance of exposing students to information that enable them to efficiently achieve practicum placement goals. Thirdly, the need to utilise both reflective and skills based assessment to assess the development of counselling skills, as well as the completion of tasks and duties that are required of students. Further information was gleaned about the research participants' perspectives on supervision procedures, practicum contracts, benefits of having a practicum placement and suggested training areas for the proposed TWH supervision module.

year: 1995-01-01