Statistically based approach to select worst-case groundwater scenarios for environmental risk assessment of pesticides in Brazil Rômulo P. Scorza Júnior1 (
[email protected]); Fábio Henrique C. Sivieri2 2 1 Fábio Augusto S. Seabra ; Éder Comunello 1Embrapa
Agropecuária Oeste; 2Universidade Estadual de Mato Grosso do Sul (UEMS)
Introduction
Results
• Environmental risk assessment of pesticides requires exposure scenarios to estimate predicted environmental concentration (PEC) using simulation models;
90.13th percentile overall
120
100
Material and Methods
K oc DT50 = 30 days
80
60
40
25 20
20
• 1890 scenarios and weather time-series of 30 years (24 years effectively used from 1 Jan. 1989 to 31 Dec. 2012); • PEARL v.4.4.4 used to generate PEC populations (time and space) of “average annual PEC” in groundwater at 3 and 5 m depth;
e
15 18 03 30 12 33 27 15 42 21 06 36 09 39 24 10 01 28 16 40 25 13 31 17 19 34 07 02 22 37 04 29 11 41 32 14 26 20 35 23 08 38 05
0
Loca tions 80th percentil in space
10
Ti m
• Aim: to demonstrate a statistically based approach to select worst-case scenarios for groundwater using spatial variability of soil-climate data of Mato Grosso do Sul State, Brazil.
-1 = 58 L kg
80th pe rc e ntil in tim e
-1 ) L g µ ( C E P l a Ave ra ge a nnu
• Ideally, these exposure scenarios should represent realistic worst-case situations for soil-climate conditions to guarantee a safe use of pesticides and a high degree of protectiveness;
A
5
0
B 90.92th percentile overall -1 Koc = 5.8 L kg DT50 = 3 days
50 40
20
45 “dummy” pesticides
14 meteo stations
42 locations (intended area of pesticide use)
weather timeseries (24 years)
1890 scenarios for PEARL simulations Selection of 80th percentile in space and time
90th percentile TOTAL worst-case scenario
PEC population in space and time and PDF for each pesticide
Figure 2. Approach overview to select worst-case groundwater scenarios.
Loca tions
10
5
Ti m
e
3 soil types
18 03 33 27 36 12 21 30 42 06 09 15 39 24 01 16 31 10 25 28 40 04 19 07 17 34 13 32 02 37 22 29 11 26 41 20 35 08 05 14 23 38
0
perc
20
10
entil
25
15
Figure 1. Spatial distribution of meteorological stations and soil types at Mato Grosso do Sul State.
in tim
e
30
80th
-1 L ) g µ ( C E P l a u Average ann
60
0
80th percentil in space
Figure 3. Spatio-temporal distribution of “average annual PEC” values for two “dummy” pesticides in groundwater at 3 m (A) and 5 m (B) depth.
Conclusions Robust approach to select “worst-case” exposure scenarios for groundwater based on a pre-defined exposure endpoint (i.e. 90th percentile overall) by using Brazilian regionalized spatial and temporal data (i.e. soil and climate).
