Exposure Estimation and Risk Characterisation'

1
Exposure Estimation and Risk Characterisation.

• REACH RIP 3.2-2 Industry Example
• Plastics Case Anti-static additive in packaging
  masterbatch.
• Summary
• Arona
• 78 November 2006

2
Anti-static additive in LDPE masterbatch for
packaging.

• Background to the case
• This substance in this case is used as an anti
  static additive in a masterbatch ( concentrate)
  for use in a blown plastic film.
• Film is typically used for the outer packaging on
  other packed items (typically food or drink).
• Life cycle stages that are considered are
  formulation ( masterbatch manufacture),
  conversion ( film manufacture), service life (
  consumer).

3
Anti-static additive in LDPE masterbatch for
packaging.

• Approach to the case
• Team obtained descriptions of the three generic
  masterbatch manufacturing processes for
  granulate, powder and liquid.
• Team obtained descriptions of the four generic
  conversion processes of extrusion, moulding,
  calendering and coating.
• The formulator described his process conditions
  and RMMs
• The formulator estimated the process conditions
  and RMMs of the converter.
• The formulator estimated the exposure to the
  consumer.

4
Anti-static additive in LDPE masterbatch for
packaging.

• Approach to emission estimation and risk
  characterisation
• Mass balance of the anti-static substance was
  considered through the different life-cycle
  stages.
• Process conditions and RMMs and their
  effectiveness were from the Formulator and teams
  experience.
• PNEC and DNEL values still to be calculated, so
  risk characterisation is incomplete.
• Our approach needs input from a converter to
  confirm his process conditions and RMMs.
• Our approach needs input from the substance
  manufacturer to confirm various data for use in
  the tools so we can compare the tools to our mass
  balance approach.

5
Emission estimation and risk characterisation -
mass balance approach.

• Develop the background information for each life
  cycle stage
• Substance is used at 5 in the masterbatch
  recipe. After this is diluted for blowing there
  is 0.1 of the anti-static additive in the
  packaging film.
• The calculation is per event that is the batch
  process quantity in a known formulation plant. A
  batch is 400kg. There are considered to be 10
  events per 8 hour shift.
• The process hall is assumed to be 1000m3 volume
  with no forced ventilation other than air to
  replace that extracted through the dust and fume
  systems. 1000m3 is chosen to represent a typical
  SME manufacturing operation.
• Emission pathways are as follows

6
Process at Masterbatch Manufacturer(Emission
pathways are shown in red type)
Dust extraction Pathways 1 2
Vacuum sludge Pathway 3
Fume extraction Pathways 4
Closed circuit water system Pathway 5
Solid process waste Pathway 6
7
Consider losses of the substance.

• Total loss from the process is assumed to be 3.
  This is based on real experience of formulation
  process efficiencies.
• The 3 is assumed to divide in the following
  way
• Pathways 1 2 Dust through the extraction in
  the process hall 1
• Pathway 3 Volatiles and solids through vacuum
  system 0.2
• Pathway 4 Volatiles through fume extraction from
  extruder vent and die head and in the process
  hall 0.8
• Pathway 5 Dissolved in water system 0
• This pathway need to be further investigated
  because a closed system could accumulate the
  substance even at low solubility.
• Pathway 6 Plastic waste that is not reusable in
  the process 1
• Per 400kg batch there is 5 of anti static
  substance.
• This equates to 20kg

8
Calculate losses per pathway.

• For example Pathways 1 2 Antistatic substance
  in dust to workers
• Initial quantity of substance in dust per event
  1 x 20kg 200g.
• Extraction system is assumed to take 90 of dust
  (and the included substance) away 180g/event.
• This leaves 10 of the used amount in the dust
  released to the process hall 20g/event.
• Per shift 10 events take place ? total emission
  during 1 shift 200 g/8 hours
• This is diluted in the production hall (1000 m3)
  assuming full release at once and accumulation of
  dust (no air exchange) ? concentration 200
  mg/m3
• This is considered as the dust exposure
  concentration to the workers.

9
Calculate losses per pathway - continued.

• Pathways 1 2 Antistatic substance in dust to
  the environment.
• Initial quantity of substance in dust 1 x 20kg
  200g/event.
• Extraction system is assumed to take 90 of dust
  (and the included substance) away 180g/event.
• Of the 180g we assume 95 is captured in a filter
  and is disposed of to incineration as hazardous
  waste. 95 x 180g 171g/event
• Of the 180g in the extraction system 5 is
  exhausted to outside air. 5 x 180g 9g/event.
• 10 events per shift, 2 shifts per day, 220
  working days ? total amount to environment per
  year 39.6 kg/a
• Emissions to the workplace eventually reach the
  environment as well ? add 88 kg/a from production
  hall
• The total of 39.6 and 88 kg/a is considered the
  emission of the substance as dust to the
  environment.

10
Calculate exposure estimation and risk
characterisation workers inhalation.

• Workers exposure - inhalation.
• The exposure is 20g/event from dust and 16g/event
  from fume.
• This is 36g per event.
• There are 10 events per 8 hour shift so 360g per
  shift or 217g per worker per day, assuming the
  worker works 220 days per year.
• Volume of process hall is taken as 1000m3 hence
  worker is exposed to 360mg/m3 per workday.
• Worker inhalation risk characterisation.
• There are DNEL values available.
• DNEL inhalation, repeated, worker 3.16mg/m3
• Thus we can say there is potentially a risk to
  workers from this substance in the ES given.

11
Calculate exposure estimation and risk
characterisation workers dermal.

• Workers exposure - dermal.
• The exposure is 20g from dust per event.
• There are 10 events per 8 hour shift so 200g per
  worker per day.
• Assuming 2 of this dust could fall on a surface
  and get on to the hands of a worker wearing no
  gloves.
• 2 x 200g 4g per pair of hands
• Pair of hands is 250 cm2 so density of exposure
  is potentially 0.016g per cm2
• Worker dermal risk characterisation.
• We are in the process of calculating DNEL values.
  
• The potential risk needs to be further
  evaluated and risk characterisation carried out.
  

12
Calculate exposure estimation and risk
characterisation environment.

• Environmental exposure.
• The exposure from the extraction/ventilation
  systems is 14.4g/event from fume 9g/event from
  dust 23.4g/event.
• We also consider the fume and dust in the process
  hall to eventually end up in the environment.
  This is 16.0g/event from fume 20g/event from
  dust 36g/event
• We assume 10 events per day x two shifts x220
  working days per year.
• 10 x 2 x 220 x (23.436.0) 261.4kg per year.
• Of the 261.4kg we assume 0 goes to water
  (insoluble), 25 goes to soil and 75 goes to
  air.
• 65.4kg per year goes to soil and 196.0kg per year
  goes to air.
• Environmental risk characterisation.
• There are no PNEC values for air or soil so no
  risk characterisation can be done at present.

13
Repeat the process for the conversion life cycle
stage.

• Background information.
• The film blowing process is assumed to take place
  in a process hall volume 1000 m3 and with three
  air changes per day.
• This volume is taken from experience of SME
  converters.
• The film blowing process is assumed to be 97
  mass efficient for the LDPE compound.
• Of the 3 loss, 2.75 is assumed to be solid
  waste plastic and 0.25 volatiles.
• The anti-static substance is present at 0.1 in
  the compound and thus the film.
• The converter is assumed to use 100t per year of
  masterbatch.
• Substance is present at 5 in the masterbatch.
• This means converter used 5t of anti-static
  substance per year.
• The converter is assumed to work 3 shifts per
  day, 230 days per year.

14
Conversion Process at Film Manufacturer
Volatiles to process hall Pathway 1
Mixing Weighing
Feeding
Blowing
Finishing
Solid plastic waste. Pathway 2
15
Losses per pathway conversion life-cycle stage.

• The loss figure total and split are not from
  measured data but are based on our knowledge of
  this life cycle stage.
• Total loss from the conversion process is 3
• Pathway 1 Volatiles escaping from the blowing
  process 0.25
• 5t 12.5kg per year.
• There is considered to be an exposure to workers
  from this pathway.
• Pathway 2 solid plastic that cannot be re-cycled
  in the process 2.75
• 5t 137.5kg per year.
• This material will be collected and disposed of
  and this pathway presents no risk to workers or
  the environment at this life cycle stage.

16
Exposure estimation and risk characterisation for
conversion workers.

• Workers exposure - inhalation.
• The exposure is 12.5kg from volatiles per year.
• There are 230 work days with 3 shifts per day.
• Exposure is 12500 / 690 18.1g per worker per
  shift.
• Volume of process hall is 1000m3.
• It is therefore estimated that a worker is
  exposed to a density of the substance of
  18.1mg/m3
• Worker inhalation risk characterisation.
• The DNEL inhalation, repeated,worker 3.16
  mg/m3.
• The worker risk characterisation is gt 1at this
  tentative ES stage.
• Workers exposure dermal and oral.
• It is considered that there is no risk to workers
  from dermal or oral exposure as the substance is
  in a volatile form only.

17
Repeat the process for the service life-cycle
stage.

• Background information.
• The finished packaging is used typically as the
  outer packaging for packets of food or drink.
• The consumer could touch 10 of one side of a
  pack. It is assumed that there is 100g of film
  per pack.
• The anti-static substance is present at 0.1 in
  the film. So there would be 0.1g of anti-static
  additive in one package.
• One side would have 0.05g if all the antistatic
  additive was on the surface (ideal case for
  product functionality).

18
Exposure estimation and risk characterisation -
consumer.

• Exposure estimation - dermal.
• The anti-static substance is present at 0.1 in
  the film. So there would be 0.1g of anti-static
  additive in one package.
• One side would have 0.05g if all the antistatic
  additive was on the surface.
• The worst case is that the consumer would touch
  10 0.05g 0.005g anti-static additive.
• The density is 0.005g per pair of hands that is
  250cm2. This is 0.02 mg/cm2
• Risk characterisation - dermal.
• The exposure at formulation was 0.016g/cm2 and so
  this worker exposure at installation is 800 times
  lower.
• No DNELs are available but it would appear that
  the risk is very low at this service life stage.
  This substance is food-contact approved and so
  this would indicate no dermal or oral risk.
• Risk characterisation inhalation and oral.
• There is considered to be no risk of inhalation
  because the substance is not airborne.

19
Add together losses from different pathways to
one target e.g.Emissions to the air
Environmentafter treatment
Environment after treatment
39.6 kg/a
63.4 kg/a
Workplace ? environment
Worplace ? environmen
5
10
Waste
95
Waste
90
88 kg/a
70.4 kg/a
90
90
790.2 kg/a
10
10
704 kg/a
880 kg/a
Extruder 160g/event 20 times / day 220 days /
year 0.8 as fumes
Mixer Extruder200g/event 20 times / day, 220
days / year 1 as dust
DUST
FUMES
Total emission to air 127.6 kg/a as dust and
133.8kg/a as vapour
20
Emissions to the air
Total emission to air 127.6 kg/a as dust and
133.8 as vapours
127.6 kg/a as dustnot readily degradable
133.8 kg/a as fumes
Deposition

• Orientation value air
• Repeated dose (dog) ? 15mg/kgBW/d
• Assessment factors2.5 (diff. Species), 10
  (general population) and 4 (allometric scaling)
• 0.15 mg/kgBW/d ? 9 mg/d for 60 kilo person
• 0.83 m3/h inhalation volume ? 19.92 m3/d
• ? Max concentration in air 0.45 mg/m3

1000m
Area 63.0000 m2 --gt Exposure 0.2g/m2 (no
degradation considered yet) Currently no
PNECsoil available due to lack of Koc
21
Emissions to water?
Closed system, however water is exchanged from
time to time (possibly 4 times per year ?
intermittent release) There may be an
accumulation of the substance in the system,as
the cooling water is reused frequently before
exchange.
Cooling system
Insoluble without quantification butaquatox
tests with conc. of 0.25 mg/l
???
Not readily degradable ?Assumption 60 release
from STP to surface water
To STP
No PNECSTP as no information on bacteria
PNECwater 0.25 µg/l
22
Next stages

• Recontact manufactureres and involve them in the
  work
• determine better PNECs/DNELs and
• develop CSA and CSR
• Alternative use dummy data
• Retry involving converters (? feedback on
  conversion)
• Further investigate the figures used in the
  different emission estimation pathways.
• Search for/develop more quantitative information
  in formulation and conversion life-cycle stages.
• Use tools