Transcript mid-report-fengheng.ppt

MID-COURSE PRESENTATION
RISK ASSESSMENT AND MONITRING
FOR ENVIRONMENTAL
CHEMICALS
•
BY
FENG HENG
GUIZHOU RESEARCH AND DESIGNING INSTITUTE OF
ENVIRONMENTAL SCIENCES, GUIYANG , CHINA
My purpose for participation of
the training program
To understand the general ideas of ecological risk
assessment for pesticide
To construct the basic know-how for conducting
relevant researches on ecological risk assessment
of pesticide
What I have achieved so far
• General framework Human Risk assessment for
environmental chemicals
• General framework of ecological Risk
assessment for pesticide
• About SIMULATION MODEL PCBF-1
• Relevant instrumental techniques
Frameworks for Risk assessment
for environmental chemicals
Research/ testing
Clinical studies
Epidemiology
Toxicology
studies
Risk Assessment
Hazard
identification
Dose-response
Assessment
Risk characterization
Data on levels of
chemicals
in
the
environment and on
rates of human contact
with and exposure to
Human
Exposure
Assessment
Research and testing
• Clinical studies and epidemiology
• Toxicology studies
• Exposure studies
Clinical studies and epidemiology
• If any, all the clinical and epidemiological
evidences concerning the adverse effects of given
chemical on human body will be reviewed as to
support the hazard identification.
Toxicology studies
• Provide information for hazard identification if
epidemiological and clinical evidence is absence
( for example, new chemical) or not enough
• .Provide information for dose-response
assessment
• Contents of the studies are subject to the specific
chemicals, chemical management regulations and
toxicology studies guidelines, etc.,
Exposure studies
• Data on levels of chemicals in the
environment and on rates of human contact
with and exposure to are reviewed
Hazard identification
• With the information from clinical and
epidemiology or toxicology studies, the
following questions can be answered:
• What chemicals?
• What toxic effects?
• What mechanisms of toxic action?
• Relevance to humans?
Dose-response assessment
How does risk of toxic effect change with
dose?
During the phase, a Dose-response curve
and NOAEL will be obtained to show the
incidence or severity of specific adverse
health effects.
Human exposure assessment
 With information from exposure studies the
following question are to be answered:
 What population?
 What dose?
 What route of exposure?
 Over what period of time?
Risk assessment
 With information from hazard identification,
dose-response assessment as well as the human
exposure assessment, the following questions are
to be answered during this phrase:
 Is there a risk to health?
 What is it’s magnitude?
 How well is it known?
Frameworks for Ecological Risk
assessment for pesticides
Hazard studies
Core data requirement for AIs
Further studies requirements on AIs
Additional study requirement for EUPs
Higher tier and field study
Risk
characterization
Exposure studies
pesticide use pattern
pesticide fate
Route of entry
Water body of concern
Mathematical models
exposures
for
generating
Subject I ‘m interested
Risk assessment and
management
About PCPF-1
General information
• Components of the model
• Basic parameters
General information
• PCPF-1 model is a simulation model for
predicting pesticide concentrations in paddy
water and surface soil through simulating the fate
and transport of pesticide in paddy water and
1cm deep oxidative paddy surface soil layer, or
the pesticide source layer (PSL)
Components of the models
• Water balance equation in paddy field
• Mass balance equation in paddy field water
compartment
• Mass balance equation in surface soil(1cm)
Water Balance Equation in Paddy Field
A
dh W
= A * [RAIN + IRR - DRAIN
dt
A：
dh / dt：
RAIN：
IRR：
DRAIN：
PERC：
ET：
- PERC
- ET
Area of Paddy Field（L2）
Temporal change of paddy water depth（LT-1）
Precipitation（LT-1）
Irrigation（LT-1）
Outflow（LT-1）
Percolation（LT-1）
Evapotranspiration（LT-1）
]
Mass Balance Equation in Paddy Water
Compartment
A
d(C W h W ) =
dt
C
A h W k dissol (C slb - C W ) + Ah Source ρb - Source k des (C S - Source - W )
ρW
+ A IRR C W -IRR - A DRAIN C W - A PERC C W


+ Ah W  - k PHOTO dE UVB - C - k BIOCHEM - W ÷
CW


dt
hＷ： Depth of paddy water (L)
CS-Source： Pesticide concentration in surface soil (MM－１)
CＷ：
Pesticide concentration in paddy water C
Pesticide concentration in irrigation water (ML-3)
W-IRR：
-3
(ML )
kHYD：
Hydrolysis rate constant of pesticide (T-1)
kdissol： Dissolution rate constant of pesticide k
Photolysis rate constant of pesticide (L１M-2T2）
PHOTO：
-1
(T )
dEUVB-C/dt： Temporal change of cumulative UV-B
Cslb： Water solubility of pesticide (ML-3)
radiation (L１M-2T）
hSource： Depth of surface soil（L)
kBIOCHEM-Ｗ：Biol.+ Chemical degradation rate constant of
bSource：Balk density of surface soil (ML-3)
pesticide (T-1)
-1
kdes： Desorption rate constant (T )
Mass Balance Equation in Surface Soil(01cm)Compartment
 AhSourceθSat-Source
 dCS-Source

+ AhSourceρb-Source ÷
=
÷
kd

 dt
1
(AhSourceθSat-Source + AhSourceρb-Sourcek d )kdissol(Cslb - C W )+ A PERC(C W - C S -Source )
kd
C
- AhSourceθSat-Source k BIOCHEM-S 1 C S-Source - AhSourceρb-sourcek des(C S-Source - W )
kd
ρW
hSource：
Sat-Source：
kd：
dＣS-Source /dt：
ＣS-Source：
ｋBIOCHEM-S：
Depth of surface soil (L)
Saturated volumetric water content (L3L-3）
Adsorption coefficient (LM-3)
Temporal Change of pesticide concentration in surface soil (MM-1T-1）
Pesticide concentration in surface soil (MM-1)
Degradation rate of pesticide in surface soil (T-1)
Input parameters and data files for PCPF-1 simulation
＜Data files＞
＜Parameters＞
Input parameters for
paddy water
• Daily water balance
1
2
Maximum simulation period
Time interval
Unit
day
day
3
Application rate
g/m
4
5
6
7
8
9
Paddy field area
Water solubility of the pesticide
The dissolution rate constant
The 1st phase desorption rate constant*
The 2nd phase desorption rate constant*
Mass transfer coeff. of pesticide volatilization
m
mg/L
1/day
1/day
1/day
m/day
10
11
12
13
The 1st order photolysis rate constant
The biochemical degradation rate constant
Pesticide concentration in irrigation water
2
14
Depth
15
Particle density
g/cm
16
Bulk density
g/cm
17
18
19
20
Saturated volumetric water content
Adsorption coefficient (Kd)*
The 1st phase degradation rate constant*
The 2nd phase degradation rate constant*
Input parameters for
surface soil
(precipitation, irrigation,
percolation and evapotranspiration)
2
m /kJ
1/day
mg/L
mg/L
Unit
cm
Phase intercept concentration for desorption
data
2
3
• Daily UV-B radiation
data
（below rice canopy)
3
*: Sensitive parameters
3
cm /cm
L/kg
1/day
1/day
3
Relevant instrumental techniques
• Through about 14 days practice in Horiba,
Shimazu, and Hitachi company we have
studied the basic theories and analytical
operation for the following lab instruments:
•
•
•
•
•
•
Atomic absorption spectrophotometer
High performance liquid chromatography
Gas chromatography
LC/MS
Water quality analyzer
Spectrophotometer
Interesting and Beneficial
subjects list
• Introduction and Agrochemicals (Hideo Ohkawa)
• Behavior of Pesticide in Paddy Field, Prediction
and Control of the Fate Using Simulation Model
(Kazuhiro Takagi)
• Ecological Risk Assessment of Environmental
Chemicals (Masaru Nokata)
• Safety Evaluation of Chemical Substances
(Shigeki Miyachi)
• Lab practices in HPTCAFF
Subjects expect to be followed up
• The relatively detailed study on the
simulation models (PCPF-1)
• Further strengthening for what we have
studies over analytical instrument
particularity HPLC, GC and GC-MS
• Pretreatment techniques for soil samples
Theme for action plan
• An Initial Studies on Application of a
Simulation Model(PCBF-1)for Predicting
Pesticide Concentration in Paddy Water
and Surface Soil in Paddy Field in Guizhou
Province
Thank you!