PROTECT First Proposed Levels for Environmental Protection against

PROTECT: First Proposed Levels for Environmental Protection against Radioactive Substances Definitions, Derivation Methods to Determine Thresholds, Available Effects Data, Preliminary Reasoning and Results PROTECT FP 6 -036425

Reminder of PROTECT objective within WP 3 • To derive and propose numerical target values for an extended list of ecological targets and protection levels, … explore the possibility for the application of advanced statistical methods that : (1) allow the best use of the available knowledge when this is represented by small data sets, (2) allow quantification of the associated uncertainty, (3) easily allow revision of resultant values when new knowledge becomes available. PROTECT FP 6 -036425

Definition • Protection goals: For the ecological target(s) of interest, combination of : (1) the targeted level of biological organisation Ecosystem: structure & function Communities: Populations of species Species: Population (e. g. , a population of a given ecosystem, taxonomic group, species) (2) the targeted level of protection that may take into account legal requirements Individual (sub) (e. g. , each individual for an endangered species, 95% of species for a taxonomic group or a community) -> a range of protection goals can be listed -> a range of numerical thresholds can be derived to assure compliance to those environmental protection goals PROTECT FP 6 -036425

Numerical Thresholds (1/3) Definition: a limit quantifying the interface between an acceptable stressor level (e. g. , in a given medium, in biota) and an unacceptable level [ « acceptable » being related to the protection goal] Applications : (1) Ecological Risk Assessment – used as Screening Values, associated with a tiered RA scheme; Exceeding means « do more » to better understand the risk (e. g. , the screening value in ERICA) (2) Regulation – used as Action Values, i. e. « legally » binding criteria (or standards) to meet the « legal » requirements; Exceeding means « act » (e. g. , an EQS) PROTECT FP 6 -036425

Numerical Thresholds (2/3) • Application: Planned and existing situations for which environmental impact/risk needs to be assessed (e. g. , chronic (routine) releases). Existing situations such as contaminated sites, for which a threshold may be defined to identify serious risk level triggering an immediate action/intervention (e. g. , clean up a site). • Unit : Dose Rates in Gy per unit time (e. g. , µGy/h) that may be converted into activity concentrations in media (water, sediment, soil, air) PROTECT FP 6 -036425

Numerical Thresholds (3/3) In Summary Screening Values-> to trigger further investigation in a tiered risk assessment Action Values -> to make a final decision about acceptability, trigger a regulatory action Both categories of thresholds may be: (1) Applied to the context of chronic radioactive substances releases due to planned or existing situations. (2) Designed to be protective at a pre-defined level, of different ecological targets that are potentially exposed to radioactive substances (ecosystems (terrestrial, marine and freshwater), communities or wildlife taxonomic groups, populations of a species, individuals of a specific population of a species). PROTECT FP 6 -036425

Methods for deriving thresholds (1/5) • Existing (chemical) approaches are based on available critical ecotoxicity data, typically ED 50 for acute exposure conditions (short-term) and EDR 10 for chronic exposure conditions (longterm). Exposure-response relationship from ecotoxicity tests (stressor, species, endpoint) Effect (%) 100 % Observed data Regression model 50 % 10 % ED 50 ED 10 EDR 50 Dose (Gy) Dose Rate (µGy/h) EDR 10: Dose Rate giving 10% effect in the exposed group in comparison to the control PROTECT FP 6 -036425

Methods for deriving thresholds (2/5) • Methods recommended by EC for chemicals (Technical Guidance Document (2003)) – easily adaptable to radioactive substances when ED 50 or EDR 10 are available (1) The Assessment Factor Method for small data sets Case not used Problem of Unit PROTECT FP 6 -036425

Methods for deriving thresholds (3/5) (2) The Species Sensitivity Distribution (SSD) Method statistical extrapolation models to address variation between species in their sensitivity to a stressor. The species for which results are known are representative, in terms of sensitivity, of the totality of the species in the ecosystem. The endpoints measured in laboratory tests are indicative of effects on populations in the field. PAF (%) 100 Calculation of a dose rate that is assumed to protect a given % of species 80 EDR 10 60 40 In the Technical Guidance Document (2003): the agreed concentration is the hazardous 20 concentration affecting 5 % of species to a 10%. 5% Dose Rate (µGy/h) 0 When it remains other extrapolation issues, the 1 10 10000 TGD recommends to apply an additional AF (15) HDR : Dose rate giving 5% of the 5% species affected to a 10% effect PROTECT FP 6 -036425

Methods for deriving thresholds (4/5) (3) a weight of evidence approach using data from field exposures (field measurements of biodiversity indexes co-occurring with stressor(s) levels) ->Concerning radioactive substances, such data series may be available for some specific sites (e. g. , uranium mining sites and long-term ecological surveillance – SQGs for ERA of metals and radionuclides) PROTECT FP 6 -036425

Methods for deriving thresholds (5/5) • In summary 3 main methodologies may be used (combined) for deriving thresholds (methods 1 & 2 reviewed/compared during ERICA): (1) the Assessment Factor method when few ecotoxicity data are available, or (2) the Species Sensitivity Distribution (SSD) approach associated with an arbitrary cut-off value, which is usually set at a protection level of 95% of the species when the available data set is more robust. (3) a weight of evidence approach using data from field exposures based on critical ecotoxicity values - i. e. , stressor level in a given medium giving 10% effect in the exposed group in comparison to the control group for chronic exposure (or 50% effect for acute exposure conditions). PROTECT FP 6 -036425

Chronic effects data from FREDERICA • To apply any of the methods in a robust way, comparable critical ecotoxicity endpoints are needed i. e. EDR 10 for chronic exposure. • To meet this aim, a meta-analysis of effects data has been initiated and applied in ERICA to reconstruct dose-effect relationships exhibiting a logistic pattern. • Only data devoted to effects induced by external irradiation pathway were quantitatively adequate to be mathematically structured in terms of dose-effect relationships. • In Protect, we have included an analysis of dose-effects relationships exhibiting an hormetic pattern. PROTECT FP 6 -036425

Dose-effect relationships reconstruction (examples) Sus scrofa (mammal, pig) Response : reproduction (number of germ cells in female %of control) (ID: 629) Logistic Hormetic EDR 10 = 123. 14 PROTECT Synechococcus lividus (Cyanobacteria) Response : growth (number of cells) (ID: 804) EDR 10 = 7. 42 FP 6 -036425

Data set (EDR 10 in µGy/h) obtained for chronic g external exposure Hormetic relationship PROTECT FP 6 -036425

Chronic critical radiotoxicity values Summary and « possible » SSD-cases • Only obtained for g external exposure conditions • EDR 10 – geometric means per species and effect category and per model (logistic/hormetic) Total number of EDR 10 : 80 (logistic) + 8 (hormetic) Total number of geometric means: 24 + 6 Number of species: 18 + 3 PROTECT FP 6 -036425

First Proposed Thresholds & Reasoning for use PAF (%) 100 • Protection goals: Ecosystem (structure & function) 95% of species + AF for a high degree of conservatism 80 60 40 20 Taxonomic groups (one or several) 95% of species 5% 0 + AF for small datasets Application Category of threshold Dose Rate (µGy/h) 1 10 1000 HDR 5% HDR 5 – protective criterion in µGy/h 10000 ERA Screening Values Highly Conservative values. HDR 5 + AF of 5 from SSD- EDR 10 ecosystems. BELOW -> Stop ABOVE -> Refine the risk assessment (exposure, effect and risk) Potential Regulation Action Values Realistic values. HDR 5 + AF of 5 (or 1 -5) from SSD- taxonomic groups. BELOW-> Manage the risk (e. g. , monitoring) ABOVE -> Act to reduce the dose rate PROTECT FP 6 -036425

First Proposed Thresholds (1/3) • Ecological target : Ecosystem (structure & function) All data (n=30) HDR 5 = 45 µGy/h CI 95% = [8. 8; 207] Without the lowest data (n=29) HDR 5 = 109 µGy/h CI 95% = [36; 374] Proposed Screening value: Application of a max AF (5) -> 10 or 20 µGy/h PROTECT FP 6 -036425

First Proposed Thresholds (2/3) HDR 5 (µGy/h) Best estimate and CI 95% Taxonomic groups without enough chronic data 800 700 600 500 400 300 200 100 at In es Te ve rre rte st br ria at l. V es e Aq rte ua br tic at es Ve rte br at es rte br nv e Aq ua l. I ria tic Pl an ts s tic la nt l. P Aq ua ria Te rre st G en er ic Te Ec rre os ys st ria te m l. E co Aq sy ua st tic em Ec os ys te m 0 without the lowest data PROTECT FP 6 -036425

First Proposed Thresholds (3/3) Lowest value included Action Values (AV) Screening Values (SV) Application of AF (1 -5) possible Application of AF of 5 HDR 5 SV HDR 5 =AV if AF=1 AV if AF=5 664 133 27 6 664 133 Aquatic Invertebrates 722 144 All Invertebrates 399 Terrestrial Vertebrates 34 7 33 7 Terrestrial Plants Aquatic Plants Generic Ecosystems 45 109 9 All Plants 22 Terrestrial Invertebrates Terrestrial Ecosystems Aquatic Ecosystems 127 11 25 2 Aquatic Vertebrates 86 PROTECT 17 All Vertebrates FP 6 -036425

Issues for discussion (not exhaustive!) • Application of an additional AF to generate Screening values for ecosystems (SV<<AV) • Application of a taxonomic weight on Plants, Invertebrates and vertebrates to establish the SSD at the ecosystemlevel • Use of extrapolation empirical models to fill the gaps for taxonomic groups (Acute-to-Chronic relationships on sensitivity distributions) • Use of other groupings (e. g. , plants, invertebrates) • Use of an additional standard for « contaminated sites » to trigger a remediation action (i. e. HDR 50% or dose rate affecting 50% of species to a 10% effect) e. g. , HDR 50 SSD-All EDR 10 - Ecosystem = 4. 2 m. Gy/h • … PROTECT FP 6 -036425