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Wilkinson SP, Gault AA, Welsh SA, Smith JP, David BO, Hicks AS, Fake DR, Suren AM, Shaffer MR, Jarman SN, Bunce M. TICI: a taxon-independent community index for eDNA-based ecological health assessment. PeerJ 2024; 12:e16963. [PMID: 38426140 PMCID: PMC10903356 DOI: 10.7717/peerj.16963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 01/26/2024] [Indexed: 03/02/2024] Open
Abstract
Global biodiversity is declining at an ever-increasing rate. Yet effective policies to mitigate or reverse these declines require ecosystem condition data that are rarely available. Morphology-based bioassessment methods are difficult to scale, limited in scope, suffer prohibitive costs, require skilled taxonomists, and can be applied inconsistently between practitioners. Environmental DNA (eDNA) metabarcoding offers a powerful, reproducible and scalable solution that can survey across the tree-of-life with relatively low cost and minimal expertise for sample collection. However, there remains a need to condense the complex, multidimensional community information into simple, interpretable metrics of ecological health for environmental management purposes. We developed a riverine taxon-independent community index (TICI) that objectively assigns indicator values to amplicon sequence variants (ASVs), and significantly improves the statistical power and utility of eDNA-based bioassessments. The TICI model training step uses the Chessman iterative learning algorithm to assign health indicator scores to a large number of ASVs that are commonly encountered across a wide geographic range. New sites can then be evaluated for ecological health by averaging the indicator value of the ASVs present at the site. We trained a TICI model on an eDNA dataset from 53 well-studied riverine monitoring sites across New Zealand, each sampled with a high level of biological replication (n = 16). Eight short-amplicon metabarcoding assays were used to generate data from a broad taxonomic range, including bacteria, microeukaryotes, fungi, plants, and animals. Site-specific TICI scores were strongly correlated with historical stream condition scores from macroinvertebrate assessments (macroinvertebrate community index or MCI; R2 = 0.82), and TICI variation between sample replicates was minimal (CV = 0.013). Taken together, this demonstrates the potential for taxon-independent eDNA analysis to provide a reliable, robust and low-cost assessment of ecological health that is accessible to environmental managers, decision makers, and the wider community.
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Affiliation(s)
- Shaun P. Wilkinson
- Wilderlab NZ Ltd., Wellington, New Zealand
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | | | | | - Joshua P. Smith
- School of Science, The University of Waikato, Hamilton, Waikato, New Zealand
- Waikato Regional Council, Hamilton, Waikato, New Zealand
| | - Bruno O. David
- Waikato Regional Council, Hamilton, Waikato, New Zealand
| | - Andy S. Hicks
- Ministry for the Environment, Wellington, New Zealand
- Hawke’s Bay Regional Council, Napier, Hawke’s Bay, New Zealand
| | - Daniel R. Fake
- Hawke’s Bay Regional Council, Napier, Hawke’s Bay, New Zealand
| | - Alastair M. Suren
- Bay of Plenty Regional Council, Tauranga, Bay of Plenty, New Zealand
| | - Megan R. Shaffer
- School of Marine and Environmental Affairs, University of Washington, Seattle, WA, United States of America
| | - Simon N. Jarman
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Michael Bunce
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
- Department of Conservation, Wellington, New Zealand
- School of Biomedical Sciences, University of Otago, Dunedin, Otago, New Zealand
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Grout L, Chambers T, Hales S, Prickett M, Baker MG, Wilson N. The potential human health hazard of nitrates in drinking water: a media discourse analysis in a high-income country. Environ Health 2023; 22:9. [PMID: 36658626 PMCID: PMC9851889 DOI: 10.1186/s12940-023-00960-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Recent studies linking low levels of nitrate in drinking water to colorectal cancer have raised public concerns over nitrate contamination. The aim of this study was to analyze the media discourse on the potential human health hazard of nitrates in drinking water in a high-income country with a large livestock industry: New Zealand (NZ). METHODS Searches of media sources ("major newspapers") held by the Factiva database for the NZ setting in the five-year period 17 December 2016 to 20 December 2021. RESULTS The largest number of media items was observed for 2017 (n = 108), the year of a NZ general election, with a notable decrease in 2020 (n = 20) that was likely due to the Covid-19 pandemic, which dominated health media. However, the percentage of these media items with a health focus steadily increased over time, from 11.1% of all articles in 2017 to 51.2% in 2021. The most commonly mentioned health hazard was colorectal cancer, followed by methemoglobinemia. The temporal pattern of media items suggests that the release of scientific studies and scholarly blogs was associated with the publication of subsequent media items. Major stakeholders involved in the discourse included representatives of local and central government, environmental and recreational interest groups, researchers, local residents, agricultural interest groups, and health organizations. Māori (Indigenous New Zealanders) values or perspectives were rarely mentioned. CONCLUSIONS Analysis of major newspapers for a five-year period indicated that a wide range of expert comment and opinions were made available to the public and policy makers on the issue of nitrates in water. While many different stakeholder views were captured in the media discourse, there is scope for the media to better report the views of Māori on this topic. There is also a need for articles detailing the health issues to also refer to the environmental, recreational, and cultural aspects of protecting water quality to ensure that the public, policy makers, and regulators are aware of co-benefits.
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Affiliation(s)
- Leah Grout
- Department of Public Health, University of Otago, Wellington, 6021, New Zealand.
- Larner College of Medicine, University of Vermont, VT, Burlington, USA.
| | - Tim Chambers
- Department of Public Health, University of Otago, Wellington, 6021, New Zealand
| | - Simon Hales
- Department of Public Health, University of Otago, Wellington, 6021, New Zealand
| | - Marnie Prickett
- Department of Public Health, University of Otago, Wellington, 6021, New Zealand
| | - Michael G Baker
- Department of Public Health, University of Otago, Wellington, 6021, New Zealand
| | - Nick Wilson
- Department of Public Health, University of Otago, Wellington, 6021, New Zealand
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Kelly MG, Phillips G, Teixeira H, Várbíró G, Salas Herrero F, Willby NJ, Poikane S. Establishing ecologically-relevant nutrient thresholds: A tool-kit with guidance on its use. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150977. [PMID: 34656586 DOI: 10.1016/j.scitotenv.2021.150977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/20/2021] [Accepted: 10/10/2021] [Indexed: 06/13/2023]
Abstract
One key component of any eutrophication management strategy is establishment of realistic thresholds above which negative impacts become significant and provision of ecosystem services is threatened. This paper introduces a toolkit of statistical approaches with which such thresholds can be set, explaining their rationale and situations under which each is effective. All methods assume a causal relationship between nutrients and biota, but we also recognise that nutrients rarely act in isolation. Many of the simpler methods have limited applicability when other stressors are present. Where relationships between nutrients and biota are strong, regression is recommended. Regression relationships can be extended to include additional stressors or variables responsible for variation between water bodies. However, when the relationship between nutrients and biota is weaker, categorical approaches are recommended. Of these, binomial regression and an approach based on classification mismatch are most effective although both will underestimate threshold concentrations if a second stressor is present. Whilst approaches such as changepoint analysis are not particularly useful for meeting the specific needs of EU legislation, other multivariate approaches (e.g. decision trees) may have a role to play. When other stressors are present quantile regression allows thresholds to be established which set limits above which nutrients are likely to influence the biota, irrespective of other pressures. The statistical methods in the toolkit may be useful as part of a management strategy, but more sophisticated approaches, often generating thresholds appropriate to individual water bodies rather than to broadly defined "types", are likely to be necessary too. The importance of understanding underlying ecological processes as well as correct selection and application of methods is emphasised, along with the need to consider local regulatory and decision-making systems, and the ease with which outcomes can be communicated to non-technical audiences.
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Affiliation(s)
- Martyn G Kelly
- Bowburn Consultancy, 11 Monteigne Drive, Bowburn, Durham DH6 5QB, UK; School of Geography, Nottingham University, Nottingham NG7 2RD, UK.
| | - Geoff Phillips
- Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Heliana Teixeira
- Department of Biology & CESAM, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Gábor Várbíró
- Department of Tisza Research, Institute of Aquatic Ecology, Centre for Ecological Research, Bem t'er 18/c, H-4026 Debrecen, Hungary
| | | | - Nigel J Willby
- Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Sandra Poikane
- European Commission Joint Research Centre (JRC), I-21027 Ispra, Italy
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Waite IR, Van Metre PC, Moran PW, Konrad CP, Nowell LH, Meador MR, Munn MD, Schmidt TS, Gellis AC, Carlisle DM, Bradley PM, Mahler BJ. Multiple in-stream stressors degrade biological assemblages in five U.S. regions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 800:149350. [PMID: 34399326 DOI: 10.1016/j.scitotenv.2021.149350] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Biological assemblages in streams are affected by a wide variety of physical and chemical stressors associated with land-use development, yet the importance of combinations of different types of stressors is not well known. From 2013 to 2017, the U.S. Geological Survey completed multi-stressor/multi-assemblage stream ecological assessments in five regions of the United States (434 streams total). Diatom, invertebrate, and fish communities were enumerated, and five types of potential stressors were quantified: habitat disturbance, excess nutrients, high flows, basic water quality, and contaminants in water and sediment. Boosted regression tree (BRT) models for each biological assemblage and region generally included variables from all five stressor types and multiple stressors types in each model was the norm. Classification and regression tree (CART) models then were used to determine thresholds for each BRT model variable above which there appeared to be adverse effects (multi-metric index (MMI) models only). In every region and assemblage there was a significant inverse relation between the MMI and the number of stressors exerting potentially adverse effects. The number of elevated instream stressors often varied substantially for a given level of land-use development and the number of elevated stressors was a better predictor of biological condition than was development. Using the adverse effects-levels that were developed based on the BRT model results, 68% of the streams had two or more stressors with potentially adverse effects and 35% had four or more. Our results indicate that relatively small increases in the number of stressors of different types can have a large effect on a stream ecosystem.
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Affiliation(s)
- Ian R Waite
- U.S. Geological Survey, Oregon Water Science Center, Portland, OR 97201, USA.
| | - Peter C Van Metre
- U.S. Geological Survey, Texas Water Science Center, Austin, TX 78754, USA
| | - Patrick W Moran
- U.S. Geological Survey, Washington Water Science Center, Tacoma, WA 98402, USA
| | - Chris P Konrad
- U.S. Geological Survey, Washington Water Science Center, Tacoma, WA 98402, USA
| | - Lisa H Nowell
- U.S. Geological Survey, California Water Science Center, Sacramento, CA 95819, USA
| | - Mike R Meador
- U.S. Geological Survey, Headquarters, Reston, VA 20192, USA
| | - Mark D Munn
- U.S. Geological Survey, Washington Water Science Center, Tacoma, WA 98402, USA
| | - Travis S Schmidt
- U.S. Geological Survey, Montana Water Science Center, Helena, MT 59601, USA
| | - Allen C Gellis
- U.S. Geological Survey, Maryland-Delaware-D.C. Water Science Center, Catonsville, MD 21228, USA
| | - Daren M Carlisle
- U.S. Geological Survey, Kansas Water Science Center, Lawrence, KS 66049, USA
| | - Paul M Bradley
- U.S. Geological Survey, South Carolina Water Science Center, Columbia 29210, USA
| | - Barbara J Mahler
- U.S. Geological Survey, Texas Water Science Center, Austin, TX 78754, USA
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Jones OA, Currell M, McCance W. Groundwater CSI: Unravelling Pollution Sources in Complex Environments with Liquid Chromatography Triple Quadrupole Mass Spectrometry. LCGC EUROPE 2021. [DOI: 10.56530/lcgc.eu.yf5973v7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Wastewater treatment plants (WWTP) are used worldwide to purify domestic and industrial wastewater before it is returned to the environment. Even after treatment, wastewater may still contain a variety of contaminants, including nutrients (usually nitrogen and phosphorus) and organic pollutants, such as endocrine disruptors and pesticides. These compounds can leak into groundwater via old and/or damaged infrastructure, leaching from biosolids storage areas and/or release of effluents. However, similar contaminant impacts can come from other sources, such as agriculture. It is often very difficult to distinguish the true source of such contamination, especially where wastewater treatment plants are located in agricultural areas. Robust and sensitive techniques are needed to characterize impacts where there are multiple potential sources. This study analyzed a variety of synthetic chemicals using liquid chromatography triple quadrupole mass spectrometry (LC–QQQ–MS) to generate unique fingerprints of pollution. These were used to distinguish the impact on the local groundwater of a WWTP in southeast Victoria (Australia) from that of local agriculture. The use of such novel tracers could become a valuable tool in environmental monitoring, management, and remediation in the future.
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