Tellus 2015: Update on the national geochemical mapping programme

Transcription

1 Tellus 2015: Update on the national geochemical mapping programme Kate Knights Tellus Ireland Geochemistry Programme Manager Geological Survey of Ireland Geoscience 2015, Dublin, 4 th November 2015

2 Presentation outline Progress so far on Tellus geochemistry in Ireland Regional geochemistry on a national scale Latest findings Research highlights & impacts

3 Objectives of Tellus Geochemistry Baseline geochemical mapping on a regional scale Surveys designed to measure and map concentrations of inorganic chemical elements in three surface media types: o Topsoil (depth not horizon specific c. 20 cm) o Fine fraction stream sediment (less than 150 µm fraction) from small stream catchments o Stream water from small stream catchments

4 Tellus Tellus Border NI to 2013 to 2008 National programme 2015 Tellus North Midlands 2014 Current status of Tellus geochemical surveying across the island of Ireland

5 G1 area: soil survey, Autumn 2015 G1 + G2 areas: stream survey, Summers 2016 & 2017

6 2015 fieldwork: soil surveying in G1 area, Mayo & Galway

7 Sample types routinely analysed: Topsoil (c.5 20 cm depth) Wet-sieved stream sediment (<150 µm fraction collected) Stream water (<0.45 µm filtered) Also collected & archived: Subsoil (c cm depth) Panned heavy minerals concentrate Vegetation (twig) samples

8 Current analytical methodologies Media Analytes Analytical method Topsoil Stream water Multi-element Multi-element ph LOI (proxy for C) Multi-element Anions, incl. NO 3 Organic carbon Aqua regia & ICP-MS XRFS ICP-MS Ion chromatography TIC/TOC analyser Stream sediment Multi-element PGE (Au, Pd, Pt) XRFS Fire assay & ICP-MS

9 Delivering 50% survey coverage Soil sampling / % soil collection complete Stream sampling / % stream collection complete Topsoil & stream sediment sample preparation / ongoing 2015 Geochemical analyses / ongoing 2015 Solid samples analyses Topsoil ph Topsoil LOI Topsoil XRFS Topsoil aqua regia ICP Stream sediment XRFS Stream sediment fire assay ICP Aqueous samples analyses Field chemistry tests ICP IC NPOC Data QC & mapping (periodic) / ongoing 2015 Soils dataset expected 2017 Stream sediment & water dataset expected

10 Data coming in ALSO: New soil ph and loss-onignition data for shallow and deeper soils collected so far (late 2016) New multi-element XRFS analytical data on soils from north midlands region (late 2016) New analytical data for gold & multi-element XRFS data for archive sediments from SE Ireland New multi-element XRFS analytical data on soils from border region Register for updates by

11 Some current & future applications and research highlights Research topic Topsoil Spatial variability of ph and liming management practices Predicting the likelihood of soil management based on soil information Trace elements & animal heath Cobalt and manganese deficiency for sheep Mapping diffuse pollution from aerial emissions Bioaccessibility proxies from regional geochemistry for PHEs Stream water Stream sediment Fluoride and halides, saline inputs, mobile micronutrients in water Mineral exploration Au, REEs, Pt, Zn-Pb Natural N species variability and association with rock units Elements associated with mine wastes Regional phosphorous, used as context for monitoring data Geological mapping Prospectivity analysis for minerals Natural background concentrations, defining contaminants Element mobilities between solid & aqueous phases

12 How Tellus data are relevant to Ireland s farming Map and measure the landscape s natural chemical properties. Input to regional & national strategy of balancing farming, economic and environmental pressures. Inform management decisions and use of resources incl. fertilizers/supplements. Livestock management. Reduce animal health expenditure through research. Communicating data uncertainty to data users. Certain crops for certain soils. Fertilizer management Soil processes / regeneration Soil stability & buffers to change Ecosystems & catchment management Water movement /storage in soil Trace elements for animal health Water quality challenges Natural resources

13 Study 1: Predicting likelihood of cobalt deficiency in sheep in Ireland Investigating Co-Mn data in grassland soils. Mapping likelihood of deficiency based on soil Co concentrations and soil index system & land use/livestock. o Cobalt deficiency in sheep (pine). o Cobalt uptake dependent on manganese. o Particularly affects lambs. o Linked to low live birth rates, depression & poor gastro condition. o Poor wool quality. o Costly to manage via soil and/or animal treatment. Open Access: /S

14 Study 1: Predicting likelihood of cobalt deficiency in sheep in Ireland Remedy = soil treatment, 3kg/hectare Co Different model for two distinctive geological domains. Micronutrient deficiency in pasture commonly depends on multiple soil properties. Cokriging prediction of Co and Mn can be used to assess risk of Co deficiency and quantify it. Uncertainty about the risk of Co deficiency is expressed on the IPCC 7- colour verbal scale.

15 Study 2: Quantifying the loss & impact of do nothing and decisions made using soil properties information Assessing the cost-benefit balance and gain from sampling effort, case study on County Donegal soils information. Looking at soil management hypothetical scenarios e.g. assessing soil carbon stocks, using improved high resolution information from regional national scale surveying. Can be applied to various costed agricultural management scenarios. o o Decision-making on sample size can be rationalized by the use of loss functions. Loss functions for soil information can be hard to define for policy and similar purposes. Open Access: /S

16 Study 3: Mapping the probability of soil ph requiring active management for good soil status Soil ph is a key parameter in soil/herbage/ruminant nutrient mobilities: target of soil ph 6.5 desired, actively managed at a field and farm level. Using spatial statistics to look at short- and long-range changes in soil ph with geochemical conditions. Predicting soil ph from regional al soil survey data. o o o A closer look at pasture soil ph and the risk of falling below target levels: Probability that true soil ph is less than 5.4 in pasture soil. (pale grey = most likely) Most soils in the region need attention! Substantial local variability: local sampling needed. Looking at best approach to communicate this to data users. In press. RIA book publication, Young et. al (Ed.)

17 Conference plug for 2016 ISEH 2016 & Geoinformatics Special session: Regional geochemical datasets applications to agricultural and environmental management Joint International Conference on Environment, Health, GIS & Agriculture Galway, Ireland, August 14 20, 2016 Advances in large multi-element spatial datasets detailing surficial geochemical trends provide an opportunity to assess how geochemical patterns and processes can affect a range of environmental and agricultural management challenges. This session will explore how geochemical datasets are utilised for applications for improved agricultural and environmental management, for example in examining the environmental distribution and availability of mircoand macro-nutrients, radioelements, and potentially harmful elements.

18 Thank you Acknowledgements: Tellus team, GSI, researchers & stakeholders Publication collaborators: R.M. Lark E.L. Ander M.R. Cave V. Gallagher M.M. Glennon R.P. Scanlon