title: Evaluating the potential of historic sheep dips as point sources of trace element and organochlorine pollutants

authors: Tulagi, Asaeli

subjects: Sheep dip

abstract: Sheep dipping was a historic agricultural practice where sheep were immersed into insecticides to eradicate external parasites. Historical use of pesticides has caused localised soil contamination at former sheep dipping sites. There is limited information on offsite contamination such as in stream sediments, groundwater, and surface water. Predominant contaminants at historic sheep dipping sites are arsenic (As) and organochlorine (OC) compounds. There are estimated to be 50,000 former sheep dip sites in New Zealand, of which, over 10,000 are estimated to be in the Waikato Region.  Contamination at historical sheep dip sites is potentially concerning for human and environmental health.

The objectives of this study were to (1) evaluate a range of historic sheep dips to identify sites that had the highest leaching potential; (2) characterise the selected study sites; (3) establish the extent of contamination in soil, sediments, and water; (4) evaluate the extent of offsite contamination; and (5) assess compliance to environmental guideline limits.

Soil samples from two former sheep dip sites were analysed for arsenic, copper, and organochlorines at depths of up to 20 cm. Further soil samples were analysed for arsenic at depths of up to 7.5 cm. Stream water and sediment samples were analysed for arsenic, copper, and organochlorines at upstream, downstream, and discharge point of a dip site located on a flood zone. Arsenic (0 - 2,839 mg/kg), dieldrin (0 - 8.60 mg/kg), lindane (including by-products) (0 - 0.560 mg/kg), DDT (including metabolites) (0 - 1.200 mg/kg), and endrin (0 - 0.127 mg/kg) were the main contaminants detected in soil samples. Concentrations of As (0.9 - 32 mg/kg), dieldrin (0 - 0.038 mg/kg), and benzene hexachloride (α-BHC and β-BHC) (0 - 0.0031 mg/kg) were detected in stream sediments. Organochlorine was not detected in surface water. As in surface water ranged from 0 to 0.0021 g/m3, which was well below the maximum acceptable value (MAV) of 0.01 g/m3for potable drinking water supplies.

Arsenic concentrations in 142 soil samples were well above environmental guidelines for human habitation (30 mg/kg). Dieldrin recorded low to moderate contamination in soils with one sample exceeding the environmental guideline of 6 mg/kg. Arsenic in 4 of the 18 stream sediment samples were above the interim sediment quality low level guideline (ISQG-Low) of 20 mg/kg. Dieldrin concentrations in surface sediments up to 13 cm deep were well above the interim sediment quality high level guideline (ISQG-High) of 0.008 mg/kg. α-BHC and β-BHC had no ISQG guideline. The levels detected were above the lindane guideline (ISQG-High) of 0.001 mg/kg in surface sediments. Evidence of sheep dip chemicals moving away from a sheep dip site included arsenic, dieldrin, and DDT up to 100 m downhill from a dip site located on the margins of a steep slope with an adjacent gully. Elevated As was detected in stream sediments up to 40 m downstream of a dip site located on a flood zone. High level contamination from dieldrin, α-BHC, and β-BHC were recorded in downstream sediments. 

This study recommends that sheep dips located within 15 m of a stream and margins of steep slopes with an adjacent gully should be regarded as priority sites for contaminated land investigations that should include a monitoring programme.

text: Evaluating the potential of historic sheep dips as point sources of trace element and organochlorine pollutants Sheep dipping was a historic agricultural practice where sheep were immersed into insecticides to eradicate external parasites. Historical use of pesticides has caused localised soil contamination at former sheep dipping sites. There is limited information on offsite contamination such as in stream sediments, groundwater, and surface water. Predominant contaminants at historic sheep dipping sites are arsenic (As) and organochlorine (OC) compounds. There are estimated to be 50,000 former sheep dip sites in New Zealand, of which, over 10,000 are estimated to be in the Waikato Region.  Contamination at historical sheep dip sites is potentially concerning for human and environmental health.

The objectives of this study were to (1) evaluate a range of historic sheep dips to identify sites that had the highest leaching potential; (2) characterise the selected study sites; (3) establish the extent of contamination in soil, sediments, and water; (4) evaluate the extent of offsite contamination; and (5) assess compliance to environmental guideline limits.

Soil samples from two former sheep dip sites were analysed for arsenic, copper, and organochlorines at depths of up to 20 cm. Further soil samples were analysed for arsenic at depths of up to 7.5 cm. Stream water and sediment samples were analysed for arsenic, copper, and organochlorines at upstream, downstream, and discharge point of a dip site located on a flood zone. Arsenic (0 - 2,839 mg/kg), dieldrin (0 - 8.60 mg/kg), lindane (including by-products) (0 - 0.560 mg/kg), DDT (including metabolites) (0 - 1.200 mg/kg), and endrin (0 - 0.127 mg/kg) were the main contaminants detected in soil samples. Concentrations of As (0.9 - 32 mg/kg), dieldrin (0 - 0.038 mg/kg), and benzene hexachloride (α-BHC and β-BHC) (0 - 0.0031 mg/kg) were detected in stream sediments. Organochlorine was not detected in surface water. As in surface water ranged from 0 to 0.0021 g/m3, which was well below the maximum acceptable value (MAV) of 0.01 g/m3for potable drinking water supplies.

Arsenic concentrations in 142 soil samples were well above environmental guidelines for human habitation (30 mg/kg). Dieldrin recorded low to moderate contamination in soils with one sample exceeding the environmental guideline of 6 mg/kg. Arsenic in 4 of the 18 stream sediment samples were above the interim sediment quality low level guideline (ISQG-Low) of 20 mg/kg. Dieldrin concentrations in surface sediments up to 13 cm deep were well above the interim sediment quality high level guideline (ISQG-High) of 0.008 mg/kg. α-BHC and β-BHC had no ISQG guideline. The levels detected were above the lindane guideline (ISQG-High) of 0.001 mg/kg in surface sediments. Evidence of sheep dip chemicals moving away from a sheep dip site included arsenic, dieldrin, and DDT up to 100 m downhill from a dip site located on the margins of a steep slope with an adjacent gully. Elevated As was detected in stream sediments up to 40 m downstream of a dip site located on a flood zone. High level contamination from dieldrin, α-BHC, and β-BHC were recorded in downstream sediments. 

This study recommends that sheep dips located within 15 m of a stream and margins of steep slopes with an adjacent gully should be regarded as priority sites for contaminated land investigations that should include a monitoring programme.

year: 2015

title: Effects of environmental and behavioural factors on fish swimming performance and passage success

authors: Burbach Crawford, Rachel

abstract: Instream structures like culverts, dams, and other anthropogenic barriers fragment river networks worldwide, posing a significant threat to the connectivity and migration of freshwater fish communities. Designing effective fish passage solutions requires a comprehensive understanding of the swimming abilities, behaviours, and environmental tolerances of diverse fish species. This thesis aims to address this need by investigating the factors influencing the swimming performance and passage success of multiple migratory fish species in New Zealand, with implications for improving fish passage design and connectivity restoration efforts.
Two methods for assessing swimming performance, critical swimming speed (Ucrit) and sprint swimming speed (Usprint), were compared across two fish species. Results revealed no significant statistical difference between swimming speeds estimated using Ucrit versus Usprint protocols for the pelagic Galaxias maculatus and the benthic-associated Galaxias fasciatus. This suggests that shorter time-stepped swimming speeds tests can be used to measure swimming abilities of benthic-associated species, allowing comparisons across a broader range of fish for passage design.
Inter- and intraspecies variation in swimming speeds across nine migratory New Zealand fish species was quantified. Galaxias brevipinnis, Galaxias argenteus, and Galaxias postvectis exhibited the strongest swimming abilities. Galaxias maculatus was among the weakest swimmers. Body length was positively correlated with maximum speed, indicating that barriers select against weaker swimming species and smaller individuals within species. Maximum allowable culvert velocities should be significantly lower than previous standards to accommodate most individuals across species.
The impact of varying acute water temperatures on critical swimming speeds of four migratory species was investigated. At higher temperatures (26°C), three species (Galaxias maculatus, Galaxias brevipinnis, Gobiomorphus cotidianus) exhibited significant reductions in swimming performance compared to lower temperatures (8°C, 15°C). In contrast, Galaxias fasciatus showed no water temperature-related changes. These findings underscore the importance of designing fish passages to accommodate acute temperature fluctuations, to ensure successful migration under changing environmental conditions.
Potential benefits of collective navigation were explored using the small-bodied Galaxias maculatus. Experiments with an artificial velocity barrier revealed that fish swimming in groups had faster entry and passage rates, as well as lower metabolic rates indicating reduced energy expenditure, compared to solitary individuals. These findings highlight the importance of designing fish passes to facilitate movement of gregarious species by accommodating group dynamics.
The effect of repeated exposure on passage performance through an experimental raceway with high water velocities was examined. Over five consecutive days, passage success increased significantly, suggesting a role for cognition and spatial memory in improving passage performance. However, approach and entry rates did not improve, indicating other factors like attraction flows or fish physiology may be important for locating and entering structures. 
This thesis provides insights into the factors influencing swimming performance and passage success for migratory New Zealand species. By studying variation across species in water temperature effects, group behaviour, and cognitive abilities, this research provides a comprehensive understanding to guide the development of more inclusive and effective fish passage solutions. The findings highlight the importance of accounting for many sources of variation when designing instream structures to facilitate unimpeded fish migration.

text: Effects of environmental and behavioural factors on fish swimming performance and passage success Instream structures like culverts, dams, and other anthropogenic barriers fragment river networks worldwide, posing a significant threat to the connectivity and migration of freshwater fish communities. Designing effective fish passage solutions requires a comprehensive understanding of the swimming abilities, behaviours, and environmental tolerances of diverse fish species. This thesis aims to address this need by investigating the factors influencing the swimming performance and passage success of multiple migratory fish species in New Zealand, with implications for improving fish passage design and connectivity restoration efforts.
Two methods for assessing swimming performance, critical swimming speed (Ucrit) and sprint swimming speed (Usprint), were compared across two fish species. Results revealed no significant statistical difference between swimming speeds estimated using Ucrit versus Usprint protocols for the pelagic Galaxias maculatus and the benthic-associated Galaxias fasciatus. This suggests that shorter time-stepped swimming speeds tests can be used to measure swimming abilities of benthic-associated species, allowing comparisons across a broader range of fish for passage design.
Inter- and intraspecies variation in swimming speeds across nine migratory New Zealand fish species was quantified. Galaxias brevipinnis, Galaxias argenteus, and Galaxias postvectis exhibited the strongest swimming abilities. Galaxias maculatus was among the weakest swimmers. Body length was positively correlated with maximum speed, indicating that barriers select against weaker swimming species and smaller individuals within species. Maximum allowable culvert velocities should be significantly lower than previous standards to accommodate most individuals across species.
The impact of varying acute water temperatures on critical swimming speeds of four migratory species was investigated. At higher temperatures (26°C), three species (Galaxias maculatus, Galaxias brevipinnis, Gobiomorphus cotidianus) exhibited significant reductions in swimming performance compared to lower temperatures (8°C, 15°C). In contrast, Galaxias fasciatus showed no water temperature-related changes. These findings underscore the importance of designing fish passages to accommodate acute temperature fluctuations, to ensure successful migration under changing environmental conditions.
Potential benefits of collective navigation were explored using the small-bodied Galaxias maculatus. Experiments with an artificial velocity barrier revealed that fish swimming in groups had faster entry and passage rates, as well as lower metabolic rates indicating reduced energy expenditure, compared to solitary individuals. These findings highlight the importance of designing fish passes to facilitate movement of gregarious species by accommodating group dynamics.
The effect of repeated exposure on passage performance through an experimental raceway with high water velocities was examined. Over five consecutive days, passage success increased significantly, suggesting a role for cognition and spatial memory in improving passage performance. However, approach and entry rates did not improve, indicating other factors like attraction flows or fish physiology may be important for locating and entering structures. 
This thesis provides insights into the factors influencing swimming performance and passage success for migratory New Zealand species. By studying variation across species in water temperature effects, group behaviour, and cognitive abilities, this research provides a comprehensive understanding to guide the development of more inclusive and effective fish passage solutions. The findings highlight the importance of accounting for many sources of variation when designing instream structures to facilitate unimpeded fish migration.

year: 2024

title: Radiocarbon analysis of a novel bone sample type: snapper and barracouta bone from New Zealand archaeological sites

authors: Petchey, Fiona

abstract: This dissertation investigates the potential of fish bone, specifically barracouta (Thyrsites atun) and snapper (Pagrus auratus), for routine radiocarbon analysis. Of particular interest to this study is the perceived reliability of bone ¹⁴C determinations in the New Zealand archaeological literature. Issues of bone preservation and contamination, dietary fractionation, species differences, and the reliability of different pretreatments are of key importance. Informed, critical assessment of bone determinations in New Zealand is, however, currently limited for a number of reasons. First, there have been no, or few comprehensive tests of bone pretreatment, species reliability or the influence of contamination. Second, confusion has resulted regarding the effectiveness of the varied radiocarbon pretreatments available, due in part to the complexity of some methods. This has been further hampered by the incorrect reporting of fractions isolated for ¹⁴C measurement. Third, inadequate sample selection procedures have resulted in burnt bone, sub-fossil bone and severely degraded bone, each with intrinsically different chemistries, being submitted for radiocarbon assay. Fourth, insecure provenance of the sample, or associated samples to be dated, mean that few comparisons of bone reliability could have, or can be made. Fifth, publication of results and procedures have been limited. Finally, there has been limited research into the radiocarbon measurement of bone in New Zealand due to a preconception about the reliability of bone determinations. These uncertainties with bone radiocarbon measurement are addressed in this dissertation. 

The sources of ∆¹⁴C to fish are also critical. Bone collagen and its derivatives (e.g. gelatin, tripeptides, amino acids) are the most common bone fractions isolated for radiocarbon measurement. For fish, the ¹⁴C in collagen is derived either directly, or indirectly via diet, from dissolved inorganic carbon in sea water. A number of uncertainties have previously been identified with the measurement of ¹⁴C in marine animals, including the effects of hardwater, depleted carbon from depth, or terrestrial organic carbon. These factors are investigated, and it is determined that their impact on fish bone ¹⁴C determinations depend on the immediate environment and the type of fish selected for dating. Both barracouta and snapper occupy predominantly the well-mixed surface waters around New Zealand. Studies of marine shell and snapper otolith carbon from around New Zealand, suggest that hardwater and terrestrial organic carbon are of limited influence. This requires further testing and may depend on the specific dietary preferences of each species. Of particular concern, however, is the upwelling of depleted carbon, especially at the convergence of inshore and offshore waters or at the boundary of two water masses (i.e. the Subtropical Convergence). In addition, inbuilt age is often cited as reasons for anomalous ¹⁴C determinations. This also appears to be of nominal influence, due in part to the precision of the radiocarbon technique, but also because of the relatively rapid replacement of collagen.

A range of different bone pretreatment and assessment methods are discussed. From this review it is concluded that gelatinisation following a NaOH wash, should remove better than 8% contamination (i.e. a maximum error of 42 years in a well-preserved sample of 900 BP material if contaminated by modem carbon). This pretreatment method, in combination with techniques for assessing contamination and collagen preservation, will significantly improve the likelihood of a reliable radiocarbon determination. The use of an appropriate assessment methodology also provides a wealth of information about the sample and site taphonomy.

Snapper and barracouta samples from 7 archaeological sites are analysed. Fourier Transform Infrared (FTIR) spectra, stable isotope values, N% determinations and yield data, obtained prior to and during pretreatment, are presented along with ¹⁴C information. Material from Pleasant River, Long Beach, Shag River Mouth, Twilight Beach, Houhora and Rotokura is identified as well-preserved. Bone removed from Tata Beach is of suspect preservation state due to low levels of remaining collagen, and contamination identified in the FTIR spectra of the acid-insoluble fraction. 

Radiocarbon results from Tata Beach are, however, variable, and largely inconclusive at the level of precision used. The remaining 6 sites produced reproducible fish gelatin determinations that are statistically indistinguishable from associated marine shell determinations, and in chronological agreement with charcoal samples after calibration using the marine calibration curve of Stuiver and Braziunas (1993), corrected according to the New Zealand reservoir value (∆R) (Higham and Hogg 1995). Determinations on purified tripeptides do not agree with these results. These are, however, not supported by archaeological evidence or associated ¹⁴C determinations on reliable charcoal and shell samples.

An analysis of 46 New Zealand archaeological sites with bone determinations (human, dog, fish, seal, and moa) obtained over a 40 year period is undertaken and a discard protocol applied according to the results of this dissertation. Eleven sites with bone determinations remain after application of the discard protocol. Not all are statistically indistinguishable from associated charcoal and marine shell pairs. Using geographic and climatic information, as well as intra site data, it is apparent that sites with problematic bone radiocarbon estimates are located in high rainfall areas, which have resulted in bones of poorer preservation. This, in combination with inadequate pretreatment (typically an acid wash, or acid/alkali/acid pretreatment) has resulted in some erroneous determinations.

In the light of these results it is suggested that a bone selection protocol, using a range of chemical methods, needs to be implemented in order to identify problematic samples prior to ¹⁴C analysis. Further, gelatinisation should be a minimum pretreatment. Bones <1000 years of age should be viewed with caution for radiocarbon dating when less than 40% “extractable collagen” remains, and where contamination is identified in the FTIR spectra of the acid-insoluble fraction. The adoption of complex and expensive biochemical purification techniques is not recommended.

text: Radiocarbon analysis of a novel bone sample type: snapper and barracouta bone from New Zealand archaeological sites This dissertation investigates the potential of fish bone, specifically barracouta (Thyrsites atun) and snapper (Pagrus auratus), for routine radiocarbon analysis. Of particular interest to this study is the perceived reliability of bone ¹⁴C determinations in the New Zealand archaeological literature. Issues of bone preservation and contamination, dietary fractionation, species differences, and the reliability of different pretreatments are of key importance. Informed, critical assessment of bone determinations in New Zealand is, however, currently limited for a number of reasons. First, there have been no, or few comprehensive tests of bone pretreatment, species reliability or the influence of contamination. Second, confusion has resulted regarding the effectiveness of the varied radiocarbon pretreatments available, due in part to the complexity of some methods. This has been further hampered by the incorrect reporting of fractions isolated for ¹⁴C measurement. Third, inadequate sample selection procedures have resulted in burnt bone, sub-fossil bone and severely degraded bone, each with intrinsically different chemistries, being submitted for radiocarbon assay. Fourth, insecure provenance of the sample, or associated samples to be dated, mean that few comparisons of bone reliability could have, or can be made. Fifth, publication of results and procedures have been limited. Finally, there has been limited research into the radiocarbon measurement of bone in New Zealand due to a preconception about the reliability of bone determinations. These uncertainties with bone radiocarbon measurement are addressed in this dissertation. 

The sources of ∆¹⁴C to fish are also critical. Bone collagen and its derivatives (e.g. gelatin, tripeptides, amino acids) are the most common bone fractions isolated for radiocarbon measurement. For fish, the ¹⁴C in collagen is derived either directly, or indirectly via diet, from dissolved inorganic carbon in sea water. A number of uncertainties have previously been identified with the measurement of ¹⁴C in marine animals, including the effects of hardwater, depleted carbon from depth, or terrestrial organic carbon. These factors are investigated, and it is determined that their impact on fish bone ¹⁴C determinations depend on the immediate environment and the type of fish selected for dating. Both barracouta and snapper occupy predominantly the well-mixed surface waters around New Zealand. Studies of marine shell and snapper otolith carbon from around New Zealand, suggest that hardwater and terrestrial organic carbon are of limited influence. This requires further testing and may depend on the specific dietary preferences of each species. Of particular concern, however, is the upwelling of depleted carbon, especially at the convergence of inshore and offshore waters or at the boundary of two water masses (i.e. the Subtropical Convergence). In addition, inbuilt age is often cited as reasons for anomalous ¹⁴C determinations. This also appears to be of nominal influence, due in part to the precision of the radiocarbon technique, but also because of the relatively rapid replacement of collagen.

A range of different bone pretreatment and assessment methods are discussed. From this review it is concluded that gelatinisation following a NaOH wash, should remove better than 8% contamination (i.e. a maximum error of 42 years in a well-preserved sample of 900 BP material if contaminated by modem carbon). This pretreatment method, in combination with techniques for assessing contamination and collagen preservation, will significantly improve the likelihood of a reliable radiocarbon determination. The use of an appropriate assessment methodology also provides a wealth of information about the sample and site taphonomy.

Snapper and barracouta samples from 7 archaeological sites are analysed. Fourier Transform Infrared (FTIR) spectra, stable isotope values, N% determinations and yield data, obtained prior to and during pretreatment, are presented along with ¹⁴C information. Material from Pleasant River, Long Beach, Shag River Mouth, Twilight Beach, Houhora and Rotokura is identified as well-preserved. Bone removed from Tata Beach is of suspect preservation state due to low levels of remaining collagen, and contamination identified in the FTIR spectra of the acid-insoluble fraction. 

Radiocarbon results from Tata Beach are, however, variable, and largely inconclusive at the level of precision used. The remaining 6 sites produced reproducible fish gelatin determinations that are statistically indistinguishable from associated marine shell determinations, and in chronological agreement with charcoal samples after calibration using the marine calibration curve of Stuiver and Braziunas (1993), corrected according to the New Zealand reservoir value (∆R) (Higham and Hogg 1995). Determinations on purified tripeptides do not agree with these results. These are, however, not supported by archaeological evidence or associated ¹⁴C determinations on reliable charcoal and shell samples.

An analysis of 46 New Zealand archaeological sites with bone determinations (human, dog, fish, seal, and moa) obtained over a 40 year period is undertaken and a discard protocol applied according to the results of this dissertation. Eleven sites with bone determinations remain after application of the discard protocol. Not all are statistically indistinguishable from associated charcoal and marine shell pairs. Using geographic and climatic information, as well as intra site data, it is apparent that sites with problematic bone radiocarbon estimates are located in high rainfall areas, which have resulted in bones of poorer preservation. This, in combination with inadequate pretreatment (typically an acid wash, or acid/alkali/acid pretreatment) has resulted in some erroneous determinations.

In the light of these results it is suggested that a bone selection protocol, using a range of chemical methods, needs to be implemented in order to identify problematic samples prior to ¹⁴C analysis. Further, gelatinisation should be a minimum pretreatment. Bones <1000 years of age should be viewed with caution for radiocarbon dating when less than 40% “extractable collagen” remains, and where contamination is identified in the FTIR spectra of the acid-insoluble fraction. The adoption of complex and expensive biochemical purification techniques is not recommended.

year: 1998