31:T8ca,The aim of this notebook is to display and interpret the results of measurements of tritium (H-3) in fish that have been made available by TEPCO, Nuclear Regulatory Authority and the Ministry of Environment as part of Japan's [Comprehensive Radiation Monitoring Plan](https://radioactivity.nra.go.jp/en/plan). Results for both organically bound tritium (OBT) and tissue free water tritium (TFWT) are included. All data has been retrieved from: [TEPCO's ORBS Overarching Radiation-monitoring data Browsing System](https://www.monitororbs.jp/en/). The notebook is a work in progress and will evolve. Please send any observations to [NAML-MARIS.Contact-Point@iaea.org](mailto:NAML-MARIS.Contact-Point@iaea.org). References: - [TEPCO's Treated Water Portal Site](https://www.tepco.co.jp/en/decommission/progress/watertreatment/index-e.html) - [IAEA's ALPS Treated Water Discharge Website](https://www.iaea.org/topics/response/fukushima-daiichi-nuclear-accident/fukushima-daiichi-alps-treated-water-discharge) ## What is the current situation? The situation regarding the influence of the discharges is summarised in the following charts. The first two timeseries show TFWT and OBT activity concentrations respectively from all sampling locations (within 25km of the discharge outlet) plotted against sampling date. We can observe that the levels of H-3 in some samples measured since the start of discharges in August 2023 are elevated relative to the long-term background - approximately 0.1 - 0.2 Bq/L for TFWT and < 0.04 Bq/kg fresh mass for OBT. During discharge periods - indicated by the grey areas - a small number of samples were analysed to have slightly elevated levels - up to a maximum of 1.6 Bq/L for TFWT and 0.11 Bq/kg fresh mass for OBT in October 2023. So far no elevated activity concentrations have been observed for fish sampled outside of discharge periods. It can be noted that many measurements of samples result in so called "non-detects" whereby the H-3 levels in the sample are too low to be detected. The limits of detection are around 0.08 Bq/L for TFWT and vary between 0.03 and 0.06 Bq/kg fresh mass for OBT. Detection limits depending on a number of factors including analytical method employed and counting times. 32:T4b1,function plot2Cols(data, dischargePeriods, fdnppIndustrialArea, { filter = { nuclide: "H-3", start: new Date("2022-06-01"), stations: allStations, end: new Date(), distance: 2.5 }, discharges = { fillOpacity: 1 }, map = { zoomRadius: 1.5, distance: 2, height: 300 }} = {}) { return html`

${plotConcentrations(data, dischargePeriods, {...filter, ...discharges})}

${plotMap(data, fdnppIndustrialArea, {...filter, ...map})}

` }33:Tcc8,function plotConcentrations(data, dischargePeriods, { nuclide = "H-3:TFWT", // Possible values: "cs-134", "cs-137", "h-3" start = new Date("2021-03-15"), end = new Date(), distance = 10, // In km orgs = allOrgs, stations = allStations, excludeStations = false, fillOpacity = 0.7, yDomain = null, width = 800, height = 320 } = {}) { let dataSelected = data.filter((d) => ( d.nuclide == nuclide && d.begperiod >= start && d.begperiod <= end && d.distance <= distance && orgs.includes(d.org) && (excludeStations ? !stations.includes(d.station) : stations.includes(d.station)) )) let dataSelected2 = data.filter((d) => ( d.nuclide == nuclide && d.begperiod >= start && d.begperiod <= end && d.distance <= distance && orgs.includes(d.org) //stations.includes(d.station) )); if (yDomain === null) { yDomain = [d3.min(dataSelected2, (d) => d.valueReported), d3.max(dataSelected2, (d) => d.valueReported)]; } return Plot.plot({ width: width, height: height, x: { label: "Sampling date" }, y: { domain: yDomain, label: nuclide == "H-3:OBT" ? "Activity concentration (Bq/kg fresh mass)" : "Activity concentration (Bq/L)" }, grid: true, color: { scheme: "Tableau10", legend: true }, marks: [ Plot.rect(dischargePeriods, { x1: "from", y1: yDomain[0], x2: "to", y2: yDomain[1], stroke: null, fill: "black", fillOpacity: 0.1 }), Plot.dot(dataSelected2, { x: "begperiod", y: "valueReported", fill: "gray", fillOpacity: 0.3, sort: (d) => /Detected/.test(d.isDetected), // tip: true }), Plot.dot(dataSelected, { x: "begperiod", y: "valueReported", fill: "isDetected", fillOpacity: fillOpacity, sort: (d) => /Detected/.test(d.isDetected), // tip: true }), Plot.tip(dataSelected, Plot.pointer({ x: "begperiod", y: "valueReported", title: (d) => [(nuclide == "H-3:OBT" ? "Activity concentration (Bq/kg fresh mass): " : "Activity concentration (Bq/L): ") + (d.isDetected == "Not detected" ? "<" : "") +d.valueReported, "Sample date: " + d3.utcFormat("%B %d, %Y")(d.begperiod), "Location: " + d.station, "Species: " + d.Sample, "Nuclide: " + d.nuclide, "Unit: " + d.displayUnit, "Organisation: " + d.org].join("\n")})), // Plot.ruleY([0]) ], caption: `${nuclide} data from ${(stations.length == allStations.length || excludeStations) ? " all": ""} ${orgs} sampling locations ${excludeStations ? "except " : ""} ${stations.length == allStations.length ? "": stations} within ${distance} km from the ALPS TW discharge outlet.` }); }34:T861,function plotMap(data, sitePoly, { center = COORD_ORIGIN, zoomRadius = 1.5, nuclide = "H-3", // Possible values: "cs-134", "cs-137", "h-3" start = new Date("2021-03-15"), end = new Date(), distance = 10, // In km orgs = allOrgs, stations = allStations, excludeStations = false, width = 400, height = 320 } = {}) { let dataSelected = data.map((d) => { let meetsConditions = ( d.nuclide === nuclide && d.begperiod >= start && d.begperiod <= end && d.distance <= distance && orgs.includes(d.org) && (excludeStations ? !stations.includes(d.station) : stations.includes(d.station)) ); return { ...d, isSelected: meetsConditions } }); let uniqueStations = getUniqueStations(dataSelected) return Plot.plot({ width: width, height: height, projection: { type: "azimuthal-equidistant", rotate: center.map((d) => -d), domain: zoomRadius > distance? getCircle(center, zoomRadius) : getCircle(center, distance), inset: 5 }, marks: [ Plot.geo(land, { fill: "#CFD8DC"}), Plot.geo(sitePoly, { fill: "#CFD8DC", }), Plot.geo(getCircle(center, distance), { stroke: "#555", strokeWidth: 0.5, strokeDasharray: "4,3" }), Plot.dot(uniqueStations, { x: "lon", y: "lat", fill: d => d.isSelected ? "#000" : "#FFF", stroke: "#000", strokeWidth: 0.5, r: 3, // tip: true, title: (d) => `Station name: ${d.station}` }), Plot.tip(uniqueStations, Plot.pointer({ x: "lon", y: "lat", title: (d) => ["Location: " + d.station, "Organisation: " + d.org].join("\n")})), Plot.geo(turf.point(center), { fill: "white", stroke: "#BF360C", strokeWidth: 4, r: 4 }) ] })}35:[{"id":"138c40f115dafdad5b6ccb00b4d83ef62842b522392fa1fb2a8198e46ede014c9f37c69f3727e12b0fc8192ed767850689d48a8173da45b70051f20c3d1b85cb","href":"https://static.observableusercontent.com/files/138c40f115dafdad5b6ccb00b4d83ef62842b522392fa1fb2a8198e46ede014c9f37c69f3727e12b0fc8192ed767850689d48a8173da45b70051f20c3d1b85cb","name":"FDNPP-industrial-area.geojson","type":"application/geo+json","lastModified":1733553046784.59,"size":31778}] 2f:{"title":"Tritium activity concentrations in fish near to Fukushima Daiichi Nuclear Power Station (FDNPS)","cells":[{"id":0,"value":"# Tritium activity concentrations in fish near to Fukushima Daiichi Nuclear Power Station (FDNPS)\n\n","pinned":false,"hidden":false,"mode":"md"},{"id":457,"value":"$31","pinned":false,"hidden":false,"mode":"md"},{"id":1170,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter:{\n nuclide: \"H-3:TFWT\",\n start: new Date(\"2022-06-01\"), \n distance: 25\n },\n map: {\n distance: 25,\n zoomRadius: 1.5\n } \n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":1843,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter:{\n nuclide: \"H-3:OBT\",\n start: new Date(\"2022-06-01\"), \n distance: 25\n },\n map: {\n distance: 25,\n zoomRadius: 25\n } \n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":1739,"value":"The charts below show detected TFWT activity concentrations in fish from all sampling locations against the distance from the discharge outlet. We contrast data from before and after the first ALPS treated water discharges started on 24 August 2023. In the right-hand graph - showing results since discharges started - we can observe elevated levels of H-3 out to a distance of approximately 2 km from the discharge outlet. \n","pinned":false,"hidden":false,"mode":"md"},{"id":1599,"value":"

\n ${distanceChartBefore}\n

\n ${distanceChartAfter}\n

\n\n","pinned":false,"hidden":false,"mode":"md"},{"id":1994,"value":"For completeness the chart below shows detected OBT activity concentrations in fish from all sampling locations against the distance from the discharge outlet. In this case no detected activity concentrations were observed before the ALPS treated water discharges started. In the case of OBT the data is quite sparse. ","pinned":false,"hidden":false,"mode":"md"},{"id":1985,"value":"distanceChartOBT = Plot.plot({\n inset: 10, width: 580,\n x: { type: \"log\", grid: true, label: \"Distance from discharge outlet (km)\" },\n y: { type: \"sqrt\", grid: true, label: \"Activity concentration (Bq/kg fresh mass)\", domain: [0.01, 0.2]},\n grid: true,\n color: {\n scheme: \"Greens\",\n },\nmarks: [ \n Plot.dot(\n data.filter(d => (d.nuclide == \"H-3:OBT\" && d.activity)),\n Plot.hexbin(\n { fill: \"count\" },\n {\n x: \"distance\",\n y: \"activity\",\n binWidth: 10,\n stroke: \"#888\",\n strokeWidth: 0.8, tip: true\n }\n )\n),\n \n]})\n ","pinned":false,"hidden":false,"mode":"ojs"},{"id":84,"value":"## Utilities","pinned":false,"hidden":false,"mode":"md"},{"id":1135,"value":"$32","pinned":false,"hidden":false,"mode":"ojs"},{"id":128,"value":"$33","pinned":false,"hidden":false,"mode":"ojs"},{"id":704,"value":"function getCircle(center, radius_km) {\n return d3.geoCircle()\n .center(center)\n .radius((radius_km / (6371 * Math.PI * 2)) * 360)\n .precision(10)()}","pinned":false,"hidden":false,"mode":"ojs"},{"id":982,"value":"function getUniqueStations(data) {\n let uniqueStations = new Set() \n data.forEach(d => uniqueStations.add(d.station))\n const uniqueStationsData = Array.from(uniqueStations).map(station => {\n const stationEntries = data.filter(d => d.station === station);\n const isSelected = stationEntries.some(d => d.isSelected);\n const firstEntry = stationEntries[0];\n return {\n lon: firstEntry.lon,\n lat: firstEntry.lat,\n station: firstEntry.station,\n org: firstEntry.org,\n distance: firstEntry.distance,\n isSelected: isSelected\n };\n });\n return uniqueStationsData\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":720,"value":"$34","pinned":false,"hidden":false,"mode":"ojs"},{"id":1703,"value":"distanceChartAfter = Plot.plot({\n inset: 10, \n x: { type: \"log\", grid: true, label: \"Distance from discharge outlet (km)\" },\n y: { type: \"sqrt\", grid: true, label: \"Activity concentration (Bq/L)\", domain: [0.01, 2]},\n grid: true,\n color: {\n scheme: \"Greens\",\n },\nmarks: [ \n Plot.dot(\n data.filter(d => (d.nuclide == \"H-3:TFWT\" && d.activity != null && d.begperiod >= new Date(\"24-Aug-2023\"))),\n Plot.hexbin(\n { fill: \"count\" },\n {\n x: \"distance\",\n y: \"activity\",\n binWidth: 10,\n stroke: \"#888\",\n strokeWidth: 0.8, tip: true\n }\n )\n),\n Plot.text(['After 24 August 2023'], {frameAnchor: \"top-right\",dx: -25, dy: 25, fontSize: 12, fontWeight: \"bold\"}), \n// Plot.line(data, {x: \"distance\", y: 1, stroke: \"red\"}),\n// Plot.line(data, {x: \"distance\", y: 0.1, stroke: \"red\"}),\n// Plot.ruleY([0]),Plot.ruleX([0])\n]})\n ","pinned":false,"hidden":false,"mode":"ojs"},{"id":1761,"value":"distanceChartBefore = Plot.plot({\n inset: 10, \n x: { type: \"log\", grid: true, label: \"Distance from discharge outlet (km)\" },\n y: { type: \"sqrt\", grid: true, label: \"Activity concentration (Bq/L)\", domain: [0.01, 2]},\n grid: true,\n color: {\n scheme: \"Greens\",\n },\nmarks: [ Plot.dot(\n data.filter(d => (d.nuclide == \"H-3:TFWT\" && d.activity != null && d.begperiod < new Date(\"24-Aug-2023\") && d.begperiod >= new Date(\"01-Jun-2022\"))),\n Plot.hexbin(\n { fill: \"count\" },\n {\n x: \"distance\",\n y: \"activity\",\n binWidth: 10,\n stroke: \"#888\",\n strokeWidth: 0.8, tip: true\n }\n )\n),\nPlot.text(['Before 24 August 2023'], {frameAnchor: \"top-right\",dx: -25, dy: 25, fontSize: 12, fontWeight: \"bold\"}), \n// Plot.line(data, {x: \"distance\", y: 1, stroke: \"red\"}),\n// Plot.line(data, {x: \"distance\", y: 0.1, stroke: \"red\"}),\n// Plot.ruleY([0]),Plot.ruleX([0])\n]})\n ","pinned":false,"hidden":false,"mode":"ojs"},{"id":101,"value":"### Constants","pinned":false,"hidden":false,"mode":"md"},{"id":34,"value":"//COORD_ORIGIN = [141.045563099841, 37.42964719370964]\nCOORD_ORIGIN = [141.045417, 37.429167]","pinned":false,"hidden":false,"mode":"ojs"},{"id":87,"value":"### Scales","pinned":false,"hidden":false,"mode":"md"},{"id":36,"value":"distScale = d3.scaleThreshold([2.5], distThresholdLabel)","pinned":false,"hidden":false,"mode":"ojs"},{"id":38,"value":"distThresholdLabel = [\"< 2.5 km\", \">= 2.5 km\"]","pinned":false,"hidden":false,"mode":"ojs"},{"id":5,"value":"## Data loading","pinned":false,"hidden":false,"mode":"md"},{"id":714,"value":"### Geographical layers","pinned":false,"hidden":false,"mode":"md"},{"id":710,"value":"fdnppIndustrialAreaRaw = FileAttachment(\"FDNPP-industrial-area.geojson\").json()","pinned":false,"hidden":false,"mode":"ojs"},{"id":793,"value":"fdnppIndustrialArea = turf.rewind(fdnppIndustrialAreaRaw, { reverse: true })","pinned":false,"hidden":false,"mode":"ojs"},{"id":716,"value":"world = (\n await fetch(\"https://cdn.jsdelivr.net/npm/world-atlas@2/land-50m.json\")\n).json()","pinned":false,"hidden":false,"mode":"ojs"},{"id":726,"value":"land = topojson.feature(world, world.objects.land)","pinned":false,"hidden":false,"mode":"ojs"},{"id":718,"value":"### Measurements","pinned":false,"hidden":false,"mode":"md"},{"id":135,"value":"dischargePeriods = [\n { from: \"2023-08-24\", to: \"2023-09-01\", batch: 1 },\n { from: \"2023-10-05\", to: \"2023-10-23\", batch: 2 },\n { from: \"2023-11-02\", to: \"2023-11-20\", batch: 3 },\n { from: \"2024-02-28\", to: \"2024-03-17\", batch: 4 },\n { from: \"2024-04-19\", to: \"2024-05-07\", batch: 5 },\n { from: \"2024-05-17\", to: \"2024-06-04\", batch: 6 },\n { from: \"2024-06-28\", to: \"2024-07-16\", batch: 7 },\n { from: \"2024-08-07\", to: \"2024-07-25\", batch: 8 },\n { from: \"2024-09-26\", to: \"2024-10-15\", batch: 9 },\n { from: \"2024-10-17\", to: \"2024-11-05\", batch: 10 },\n { from: \"2025-03-12\", to: \"2025-03-30\", batch: 11 },\n { from: \"2025-04-10\", to: \"2025-04-27\", batch: 12 },\n { from: \"2025-07-14\", to: \"2025-08-03\", batch: 13 },\n { from: \"2025-08-07\", to: \"2025-08-25\", batch: 14 },\n { from: \"2025-09-11\", to: \"2025-09-29\", batch: 15 },\n { from: \"2025-10-30\", to: \"2025-11-17\", batch: 16 },\n { from: \"2025-12-04\", to: new Date(), batch: 17 }\n].map((d) => ({ from: new Date(d.from), to: new Date(d.to) }))","pinned":false,"hidden":false,"mode":"ojs"},{"id":1470,"value":"dataRawInit = d3.csv(\"https://raw.githubusercontent.com/RML-IAEA/iaea.orbs/refs/heads/main/stations/transformed/csv/fish_data.csv\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":1485,"value":"dataRaw = dataRawInit.map((d) => ({ ...d,\n lon: +d[\"lon\"],\n lat: +d[\"lat\"], \n begperiod: new Date(d[\"begperiod\"]),\n nuclide: d[\"Radionuclide\"],\n Unit: d[\"Radionuclide\"] == \"H-3:TFWT\" && d[\"Unit\"] == \"Bq/L-water\" ? \"Bq/L\" : d[\"Unit\"],\n activity: d[\"Dt\"].length > 0 ? +d[\"Dt\"] : null, \n uncertainty: d[\"Dt_unc\"].length > 0 ? +d[\"Dt_unc\"] : null, \n dl: d[\"ND\"].length > 0 ? +d[\"ND\"] : null,\n isDetected: d[\"Dt\"].length > 0 ? \"Detected\" : \"Not detected\",\n valueReported: d[\"Dt\"].length > 0 ? +d[\"Dt\"] : +d[\"ND\"],\n distance: turf.distance(turf.point(COORD_ORIGIN), turf.point([+d[\"lon\"], +d[\"lat\"]])),\n displayUnit: d[\"Radionuclide\"] == \"H-3:TFWT\" ? \"Bq/L\" : \"H-3:OBT\" ? \"Bq/kg fresh mass\" : d[\"Unit\"],\n \n}))\n// .filter(d => (d.org == \"NRA\"))","pinned":false,"hidden":false,"mode":"ojs"},{"id":1870,"value":"data = dataRaw.filter(d => !(d.nuclide == \"H-3\") && !(d.nuclide == \"H-3:OBT\" && d.Unit == \"Bq/L-combustion water\") && !(d.nuclide == \"H-3:OBT\" && d.Unit == \"Bq/L\") && !(d.nuclide == \"H-3:TFWT\" && d.Unit == \"Bq/kg-fresh\") && !(d.activity == null && d.dl == null) && !(d.nuclide == \"Cs-134\") && !(d.nuclide == \"Cs-137\")) \n \n\n\n\n","pinned":false,"hidden":false,"mode":"ojs"},{"id":327,"value":"allStations = [...new Set(data.map(d => d.station))]","pinned":false,"hidden":false,"mode":"ojs"},{"id":508,"value":"allOrgs = [...new Set(data.map(d => d.org))]","pinned":false,"hidden":false,"mode":"ojs"},{"id":635,"value":"new Set(data.map(d => d.nuclide))","pinned":false,"hidden":false,"mode":"ojs"},{"id":9,"value":"## Imports","pinned":false,"hidden":false,"mode":"md"},{"id":12,"value":"turf = require(\"@turf/turf@7\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":14,"value":"_ = require(\"lodash\")","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W35","stdlib":"1","titling":"auto"}