title: Natural and anthropogenic lead in sediments of the Rotorua lakes, New Zealand

authors: Pearson, Lisa Kyle

subjects: lead alkyls

abstract: Global atmospheric sources of lead have increased more than 100-fold over the past century as a result of deforestation, coal combustion, ore smelting and leaded petroleum. Lead compounds generally accumulate in depositional areas across the globe where, due to low solubility and relative freedom from microbial degradation, the history of their inputs is preserved. In lakes there is rapid deposition and often little bioturbation of lead, resulting in an excellent depositional history of changes in both natural and anthropogenic sources. The objective of this study was to use sediments from a regionally bounded set of lakes to provide an indication of the rates of environmental inputs of lead whilst taking into account differences of trophic state and lead exposure between lakes. Intact sediment gravity cores were collected from 13 Rotorua lakes in North Island of New Zealand between March 2006 and January 2007. Cores penetrated sediments to a depth of 16–30 cm and contained volcanic tephra from the 1886 AD Tarawera eruption. The upper depth of the Tarawera tephra enabled prescription of a date for the associated depth in the core (120 years). Each core showed a sub-surface peak in lead concentration above the Tarawera tephra which was contemporaneous with the peak use of lead alkyl as a petroleum additive in New Zealand. An 8 m piston core was taken in the largest of the lakes, Lake Rotorua, in March 2007. The lake is antipodal to the pre-industrial sources of atmospheric lead but still shows increasing lead concentrations from <2 up to 3.5 μg g−1 between the Whakatane eruption (5530 ± 60 cal. yr BP) and the Tarawera eruption. Peaks in lead concentration in Lake Rotorua are associated with volcanic tephras, but are small compared with those arising from recent anthropogenic-derived lead deposition. Our results show that diagenetic processes associated with iron, manganese and sulfate oxidation-reduction, and sulfide precipitation, act to smooth distributions of lead from anthropogenic sources in the lake sediments. The extent of this smoothing can be related to changes in sulfate availability and reduction in sulfide driven by differences in trophic status amongst the lakes. Greatest lead mobilisation occurs in mesotrophic lakes during seasonal anoxia as iron and manganese are released to the porewater, allowing upward migration of lead towards the sediment–water interface. This lead mobilisation can only occur if sulfides are not present. The sub-surface peak in lead concentrations in lake sediments ascribed to lead alkyl in petroleum persists despite the diagenetic processes acting to disperse lead within the sediments and into the overlying water.

text: Natural and anthropogenic lead in sediments of the Rotorua lakes, New Zealand Global atmospheric sources of lead have increased more than 100-fold over the past century as a result of deforestation, coal combustion, ore smelting and leaded petroleum. Lead compounds generally accumulate in depositional areas across the globe where, due to low solubility and relative freedom from microbial degradation, the history of their inputs is preserved. In lakes there is rapid deposition and often little bioturbation of lead, resulting in an excellent depositional history of changes in both natural and anthropogenic sources. The objective of this study was to use sediments from a regionally bounded set of lakes to provide an indication of the rates of environmental inputs of lead whilst taking into account differences of trophic state and lead exposure between lakes. Intact sediment gravity cores were collected from 13 Rotorua lakes in North Island of New Zealand between March 2006 and January 2007. Cores penetrated sediments to a depth of 16–30 cm and contained volcanic tephra from the 1886 AD Tarawera eruption. The upper depth of the Tarawera tephra enabled prescription of a date for the associated depth in the core (120 years). Each core showed a sub-surface peak in lead concentration above the Tarawera tephra which was contemporaneous with the peak use of lead alkyl as a petroleum additive in New Zealand. An 8 m piston core was taken in the largest of the lakes, Lake Rotorua, in March 2007. The lake is antipodal to the pre-industrial sources of atmospheric lead but still shows increasing lead concentrations from <2 up to 3.5 μg g−1 between the Whakatane eruption (5530 ± 60 cal. yr BP) and the Tarawera eruption. Peaks in lead concentration in Lake Rotorua are associated with volcanic tephras, but are small compared with those arising from recent anthropogenic-derived lead deposition. Our results show that diagenetic processes associated with iron, manganese and sulfate oxidation-reduction, and sulfide precipitation, act to smooth distributions of lead from anthropogenic sources in the lake sediments. The extent of this smoothing can be related to changes in sulfate availability and reduction in sulfide driven by differences in trophic status amongst the lakes. Greatest lead mobilisation occurs in mesotrophic lakes during seasonal anoxia as iron and manganese are released to the porewater, allowing upward migration of lead towards the sediment–water interface. This lead mobilisation can only occur if sulfides are not present. The sub-surface peak in lead concentrations in lake sediments ascribed to lead alkyl in petroleum persists despite the diagenetic processes acting to disperse lead within the sediments and into the overlying water.

year: 2010

title: Improving Water Quality through Environmental Policies and Farm Management: an Environmental Economics Analysis of Dairy Farming in  Karapiro Catchment

authors: Ramilan, Thiagarajah

subjects: Water quality

abstract: This research explores the environmental and economic implications of nitrogen discharge abatement from dairy farms. This thesis develops a framework to analyse agri-environmental policies using bio economic modelling. A novel approach has been developed using farm survey data for catchment scale modelling and policy analysis. 

Policy analysis is facilitated by various modelling techniques and software. Geographic Information Systems (GIS) are used to convert data from multiple sources to a common platform for policy analysis. Whole dairy farm system simulations coupled with a Metamodel built on the Overseer software are used to establish the relationship between farm economic returns and nitrogen discharges. This relationship is used to derive abatement costs and resolve policy implementation challenges. Data Envelopment Analysis is used to develop Environmental economic efficiency measures. Finally a stylized model is used to determine spatially optimal riparian buffer strips. 

The results show that the differences in abatement costs and environmental efficiency between farming systems are significant. The adverse effects of information asymmetry can be effectively minimized by adopting differentiated incentives and target monitoring. Riparian buffers are a cost effective abatement tool that complement abatement at the intensive margin. Clear understanding of farm heterogeneity will help to design effective policies.

Techniques for the measurement of policy impact have been successfully developed and add significantly to our knowledge of the underlying relationships. The use of simulated data for agri-environmental policy analysis is versatile and is expected to have several valuable applications. These methods can be applied to other geographic areas and research domains. This thesis provides useful tools for policy makers seeking to develop empirically informed agri environmental policy.

text: Improving Water Quality through Environmental Policies and Farm Management: an Environmental Economics Analysis of Dairy Farming in  Karapiro Catchment This research explores the environmental and economic implications of nitrogen discharge abatement from dairy farms. This thesis develops a framework to analyse agri-environmental policies using bio economic modelling. A novel approach has been developed using farm survey data for catchment scale modelling and policy analysis. 

Policy analysis is facilitated by various modelling techniques and software. Geographic Information Systems (GIS) are used to convert data from multiple sources to a common platform for policy analysis. Whole dairy farm system simulations coupled with a Metamodel built on the Overseer software are used to establish the relationship between farm economic returns and nitrogen discharges. This relationship is used to derive abatement costs and resolve policy implementation challenges. Data Envelopment Analysis is used to develop Environmental economic efficiency measures. Finally a stylized model is used to determine spatially optimal riparian buffer strips. 

The results show that the differences in abatement costs and environmental efficiency between farming systems are significant. The adverse effects of information asymmetry can be effectively minimized by adopting differentiated incentives and target monitoring. Riparian buffers are a cost effective abatement tool that complement abatement at the intensive margin. Clear understanding of farm heterogeneity will help to design effective policies.

Techniques for the measurement of policy impact have been successfully developed and add significantly to our knowledge of the underlying relationships. The use of simulated data for agri-environmental policy analysis is versatile and is expected to have several valuable applications. These methods can be applied to other geographic areas and research domains. This thesis provides useful tools for policy makers seeking to develop empirically informed agri environmental policy.

year: 2008

title: Kia rehe te matau, kia rehe te maui

authors: Winiata, Te Whatanui Huia

subjects: Taiaha, Maori business, maori development

abstract: The theory of applying successful military strategy to the world of business is not a new concept.  The connection between these two environments has often been explored, and works by Sun Tzu and others promote the connection between the battlefield and the boardroom.  The cut and thrust of the business realm is often likened to combat, and the guiding principles and beliefs that influence Generals and Field Commanders are in many ways identical to those of executives and Chief Executive Officers.

This thesis is interested in exploring the interconnectedness between battle and business from a Māori perspective.  In particular, this study explores the link between the Māori weapon known as the taiaha, and Māori business, in the belief that the lessons learnt from the various taiaha schools can be transferred to Māori business.  Likewise, the beliefs, principles and philosophies that are instilled within warriors while training with the taiaha have a valid place within Māori business, and when applied to the Māori business arena, have beneficial outcomes for those involved.

This study highlights fundamental taiaha principles that are applicable to the Māori business world.  These beliefs have been identified by a number of taiaha experts as well as successful Māori business operators.  The long term purpose of this thesis is to support Māori entering into business, by highlighting traditional values that are taught through the medium of taiaha, and showing how they can be applied to business.

text: Kia rehe te matau, kia rehe te maui The theory of applying successful military strategy to the world of business is not a new concept.  The connection between these two environments has often been explored, and works by Sun Tzu and others promote the connection between the battlefield and the boardroom.  The cut and thrust of the business realm is often likened to combat, and the guiding principles and beliefs that influence Generals and Field Commanders are in many ways identical to those of executives and Chief Executive Officers.

This thesis is interested in exploring the interconnectedness between battle and business from a Māori perspective.  In particular, this study explores the link between the Māori weapon known as the taiaha, and Māori business, in the belief that the lessons learnt from the various taiaha schools can be transferred to Māori business.  Likewise, the beliefs, principles and philosophies that are instilled within warriors while training with the taiaha have a valid place within Māori business, and when applied to the Māori business arena, have beneficial outcomes for those involved.

This study highlights fundamental taiaha principles that are applicable to the Māori business world.  These beliefs have been identified by a number of taiaha experts as well as successful Māori business operators.  The long term purpose of this thesis is to support Māori entering into business, by highlighting traditional values that are taught through the medium of taiaha, and showing how they can be applied to business.

year: 2013