Guidance for evaluating laboratory and field dissipation studies to obtain DegT50 values of plant protection products in soil

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doi:10.2903/j.efsa.2010.1936

Cited by 13 publications

(1 citation statement)

References 27 publications

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“…Furthermore, at the moment laboratory soil photolysis studies do not have a harmonised finalised OECD guideline and they are considered not to be suitable in order to derive kinetic parameters for modelling purposes, because the test conditions are rather artificial. EFSA PPR Panel ( 2010 ) says: ‘OECD (2002a) developed a guideline for measuring soil photolysis in the laboratory. […]This OECD study is commonly considered to be a “route study” rather than a “rate study”, i.e.…”

Section: Recommendations For Parameterisation Of Phototransformation ...mentioning

confidence: 99%

Scientific guidance on soil phototransformation products in groundwater – consideration, parameterisation and simulation in the exposure assessment of plant protection products

Egsmose¹,

Fait²,

Janzen³

et al. 2022

EFS2

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This Guidance Document gives recommendations how to consider transformation products from soil photolysis (‘phototransformation products’) when modelling the predicted environmental concentrations in groundwater. It describes possible parameterisations of the photolytic pathway (i.e. the photolytic half‐life and the corresponding reference irradiation) in a tiered approach using the FOCUS‐PELMO model. Following the recommendations of the EFSA guidance (2014), separate half‐lives can be derived for the surface processes (k fast ) and the biodegradation in the soil matrix (k slow ) from field dissipation studies by using biphasic models. From field dissipation studies evaluated with biphasic kinetics, the k fast value can be considered representative for the photolytic degradation on soil surface for non‐volatile substances. This value should be determined after a time‐step normalisation according to irradiance data for the location and period of the field trial, to a reference irradiance of 100 W m −2 . In case irradiance values are not available in the study, these values can be derived from databases such as AGRI4CAST or NASA, freely available in the Internet.

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Section: Recommendations For Parameterisation Of Phototransformation ...mentioning

confidence: 99%

Scientific guidance on soil phototransformation products in groundwater – consideration, parameterisation and simulation in the exposure assessment of plant protection products

Egsmose¹,

Fait²,

Janzen³

et al. 2022

EFS2

View full text Add to dashboard Cite

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Quantifying soil surface photolysis under conditions simulating water movement in the field: a new laboratory test design

Hand

Nichols

Kuet

et al. 2015

Enviro Toxic and Chemistry

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Soil surface photolysis can be a significant dissipation pathway for agrochemicals under field conditions, although it is assumed that such degradation ceases once the agrochemical is transported away from the surface following rainfall or irrigation and subsequent drainage of soil porewater. However, as both downward and upward water movements occur under field conditions, relatively mobile compounds may return to the surface, prolonging exposure to ultraviolet light and increasing the potential for degradation by photolysis. To test this hypothesis, a novel experimental system was used to quantify the contribution of photolysis to the overall dissipation of a new herbicide, bicyclopyrone, under conditions that mimicked field studies more closely than the standard laboratory test guidance. Soil cores were taken from 3 US field study sites, and the surfaces were treated with [(14) C]-bicyclopyrone. The radioactivity was redistributed throughout the cores using a simulated rainfall event, following which the cores were incubated under a xenon-arc lamp with continuous provision of moisture from below and a wind simulator to induce evaporation. After only 2 d, most of the test compound had returned to the soil surface. Significantly more degradation was observed in the irradiated samples than in a parallel dark control sample. Degradation rates were very similar to those observed in both the thin layer photolysis study and the field dissipation studies and significantly faster than in the soil metabolism studies conducted in the dark. Thus, for highly soluble, mobile agrochemicals, such as bicyclopyrone, photolysis is not terminated permanently by rainfall or irrigation but can resume following transport to the surface in evaporating water.

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Ecological risk assessment of pesticides in the EU: what factors and groups influence policy changes?

Hunka

Meli

Palmqvist

et al. 2014

Journal of Risk Research

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For the last couple of years, European environmental risk assessment (ERA) regulations have undergone significant changes. The new 1107/2009 directive which came into effect in 2011 has triggered an on-going debate on defining specific protection goals for ERA. During this period, we conducted a study on policy change among the most influential ERA stakeholders from Europe. We interviewed 43, purposively sampled, participants from the European safety authorities, plant protection product industry and academia. Transcribed interviews underwent thematic analysis conducted separately by two coders. As we followed the advocacy coalition framework, our findings focus on stakeholders' processes, interrelations and values behind the ERA policy change. The main challenges emerging from our analysis turned out to be the slow uptake of scientific developments into ERA and very broadly defined protection goals. The use of safety factors and cut-off criteria left risk assessors with many uncertainties. With ERA in its current form it turned out to be impossible to determine whether the current scheme is over-or under-protective. Still, the study shows that the problem of over-or under-protectiveness lies deep in the perception of stakeholders and depends greatly on their priorities. Academics strive for better ecological relevance as a priority. They have concerns that ERA is oversimplified. Regulators worry that ERA relies too much on risk mitigation and is possibly not protective enough, but at the same time, the majority believes that the assessment is well established and straightforward to follow. Industry representatives would like to see ERA based more on probabilistic risk assessment. Recent changes, according to risk assessment and management practitioners have led to an inevitable increase in complexity, which is not perceived as a positive thing, and does not necessarily translate into better risk assessment.

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Guidance for evaluating laboratory and field dissipation studies to obtain DegT50 values of plant protection products in soil

Cited by 13 publications

References 27 publications

Scientific guidance on soil phototransformation products in groundwater – consideration, parameterisation and simulation in the exposure assessment of plant protection products

Scientific guidance on soil phototransformation products in groundwater – consideration, parameterisation and simulation in the exposure assessment of plant protection products

Quantifying soil surface photolysis under conditions simulating water movement in the field: a new laboratory test design

Ecological risk assessment of pesticides in the EU: what factors and groups influence policy changes?

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