risk assessment to meet the requirements of Directive 93/67/EEC (as described in its associated Technical Guidance Documents),
is currently expected for new substances being Notified or for high-volume high-risk ‘existing’ substances being
reviewed under the existing chemicals regulations. However, REACH will require
the need to perform a risk assessment on virtually all substances being supplied over 1 tonne in the guise of a ‘Chemical
Safety Report’ (CSR).
the need to meet regulatory requirements, ‘risk assessment’ is an essential part of responsible care during the
production, supply or use of any chemical material. A basic risk assessment will
help determine what conditions to avoid or what protective equipment to recommend to meet statutory requirements for handling
chemicals – such as the communication or risk to customers, protection of workers and also to minimum impact on the
environment through loss or accident. The Safety Data Sheet (SDS) itself is a
product of a risk assessment in that it describes how to reduce exposure in accordance with known properties of the material.
Under REACH, the SDS will need to take into account elements of the CSR.
of risk assessment should include consideration of:
· The life cycle of the product
· Potential hazards to health and the environment
· Physical form (solid, powder, liquid, gas
· How is the product handled (manually, automatically)
· Is there contact with workers / consumers
· Is there a chance of loss to the environment
· What happens to the product after use (disposal)
The conclusions of a risk assessment is to compare the estimated exposure with the estimated
effects; for the environment, this is expressed as a PEC / PNEC, based on the ratio of predicted environmental concentration
(PEC) and predicted no effect level (PNEC). Human health elements to the risk
assessment are less clear-cut in their conclusions, but the principles remain the same with a comparison between the predicted
level of exposure and the known or estimated degree of hazard. The Derived No-Effect
Level (DNEL) is estimated from toxicity data with the application of safety factors.
The Predicted Environmental Concentration (PEC) is based on models for the degradation
or distribution of the substance in the environment (between water, air and solids) using physico-chemical and biodegradation
data. As well as the test data, other key factors include how the substance is
manufactured, formulated or used and the dilution factors from use.
The distribution of chemicals discharged to waste water treatment plants is described in the
aptly named ‘SimpleTreat’ model. This is a simplistic model that
considers the volatility (Henry’s constant, H), the partition coefficient, adsorption coefficient and biodegradation.
Log H > 3 =
Significant loss to air
coefficient Log Kow > 3 = Accumulation threat
Adsorption Coefficient Log
Koc > 3 = Adsorption to soil / sediment
60% = Biodegradable
The model, presented in tabular form in the TGD or incorporated into the software of the risk
assessment model EUSES (see below), compares each of these factors in determining the distribution of the substance in the
environment. A water soluble substance with Kow = 0, that is biodegradable, for
example, is predicted to be 76% degraded with 24% lost to surface water. But
a non-biodegradable poorly water soluble material with a Log Kow of 4, may have 56% to water and 44% to sewage sludge.
Default figures are provided in the Technical Guidance Documents (TGD) for Directive 93/67/EEC,
describing estimated concentrations of waste in effluent, standard dilution factors, sizes of water treatment plants etc.
These default values consider worse-case scenarios with, for example, 2% of material produced being lost to waste water, the
position of the production unit in a small town with a small treatment works, and with final discharge going into a small
stream. However, where only limited sites are involved in production, formulation or use, location-specific factors can be
used, such as the size of the waste treatment works, river flow rates etc. and
this can make a big difference to the final conclusion.
The Predicted No Effect Concentration (PNEC) is based on environmental effect data, such
as toxicity to fish, Daphnia or algae and is determined by applying a safety factor. For acute studies, the safety factor
of 1000 is applied to the EC50 value; ie. a Daphnia EC50 following 48 hours exposure of 50 mg/l would
lead to a PNEC of 0.05 mg/l. Longer-term studies require a smaller safety factor,
as indicated below;
Acute EC50 ÷ 1000 (Acute
= short term, eg 4 days fish)
Sub-acute EC50 ÷ 100 (Sub-acute = medium term, eg 21 days fish)
Chronic EC50 ÷
10 (Chronic = long term, pond work etc)
In the absence of effects with acute studies, the PNEC is set at 1/1000 of the limit of solubility;
likewise if there are no effects in longer-term studies, the PNEC will be 1/100 or even 1/10 of water solubility.
The ratio between PEC and PNEC is ultimately used as an indicator of risk, allowing it
to be quantitatively labelled. If the PEC is greater than the PNEC (ie. ratio
> 1 ), then it can be assumed that there is a risk of effects to the environment.
The scale of the risk can therefore be crudely measured by considering this ratio – a figure of 1 to 10 is of
low concern, but over 100 is of major concern, and limitation of supply could be required.
Conclusions under the current Directive are:
1 PEC / PNEC < 1 =
No immediate concern
2 PEC / PNEC 1 - 10 = Of concern if supply volumes increase
3 PEC / PNEC 10 - 100 =
Further data required
(Note EUSES refers to PEC/PNEC is referred to as Risk Characterisation
Ratio ‘RCR’ )
A risk assessment based on human exposure should consider the type of exposure; whether
deliberate or accidental, whether repeat or one-off or whether direct (eg. factory workers) or indirect (eg. in food or drinking
water). The physico chemical properties such as dusts, vapours or liquid
inhalation, splashing must also be considered as this can effect exposure routes. Physical
hazards, such as flammability or explosivity are also important for overall risk considerations.
Quantifying exposure is very difficult and models attempting to make this easier (such as the
EU model, EASE) rely on inputs such as vapour pressure, temperature of the process leading to exposure, dust content etc. Other than the rather simplistic model EASE, the finer points of human health risk
assessments should be left in the hands of an expert.
In an attempt to quantify ‘safe’ levels for human exposure, it is necessary to calculate
a Derived No-Effect Level (DNEL) that is based on safety factors being applied to toxicity data endpoints such as the lowest
observed adverse effect level (LOAEL) or no observed adverse effect level (NOAEL). The
DNEL effectively follows the same principle as the PNEC for environmental effects.
Exposure needs to be considered in details in the Exposure Scenario (ES) that is part of the
risk assessment process. The content of the ES is not much more than would currently
be provided in a risk assessment for new substances, but is a more formal assessment.
It is also designed to be more specific to particular uses or processes and different processes will require separate
A risk assessment based on human exposure should also be considered.
This will depend on the type of exposure, whether deliberate or accidental, whether repeat or one-off or whether direct
(eg. factory workers) or indirect (eg. in food or drinking water).
Although the Technical Guidance Document for Directive 93/67/EEC does devote a large proportion of its pages
to human health risk assessment, there is little direct support for those preparing risk assessments and there is no simple
quantitative assessment as found with environmental data. Instead, it is necessary
to make a full review of all parts of the life-cycle in which the substance can come into contact with people, including manufacture,
transport, storage, formulation, use and disposal. Parts of the life cycle may
not be obvious, such as the exposure to pigments caused by the degradation of
paints. The exposure during manufacture of a pigment or its formulation into
paint may seem obvious, as is the exposure to the wet paint when applying it to a surface.
However, the exposure to the paint from weathered surfaces is less obvious, but it all needs considering.
REACH introduces the concept of the ‘Derived No Effect Level’
(DNEL) that tries to quantify the no effect concentration for human exposure. This
is more complex than the Environmental PNEC (see above in that it considers inter-species reliability as well as the end-points
The table and notes below are taken from
draft RIP document on Risk Assessment that sets out the preliminary Technical Guidance Document (TGD)
Default assessment factors
- correction for differences
in metabolic rate per body weight
- remaining differences
- general population
- subacute to sub/semi-chronic
- sub/semi-chronic to chronic
- subacute to chronic
- difference between human
and experimental animal exposure route
- issues related to reliability
of the dose-response, incl. LOAEL/NAEL extrapolation and severity of effect
a AS = factor for allometric scaling (See
TGD TC for further details)
b Caution should be taken when the starting
point is an inhalation or diet study (See TGD TC for further details)
c Not always covering risk characterisation
of very young children (See TGD TC for further details)
d See TGD TC for further details for deviations
e This applies to systemic effects; for local
effects in general no AF for differences in duration is to be applied (since the effects are often concentration- rather than
dose-dependent). Also, the AF for intra-species differences should be the same for workers and the general population (i.e.,
for both populations a default value of 10) because no difference in sensitivity for local effects is assumed between these
two populations. Hence, one DNEL for local effects is set which can be applied to workers and the general population.
Until agreement of the TGD, the simple ‘tier I’ assessment factor
AF 1200 should be applied unless there are reliable long term data (eg Carcinogenicity) or data on a number of species, especially
non-rodent. In reality, most substances being assessed under REACH will not have
this level of data and the default factor will probably apply. Applying
AF 1200 to the 1000 mg/kg/day 28 day toxicity rat study will lead to a DNEL of
help users of chemicals, software can be obtained from European Competent Authorities (such as the UK HSE). Programs include EASE for making a simple assessment of worker exposure and EUSES for predicting environmental
is quite complex to use and interpret and can be manipulated to give a more realistic answer than if it is used at its most
basic level, using pre-set defaults. For example, simple changes can be made
to change the size of waste water treatment works or to put in the correct local dilution rate when effluent finally reaches
surface water in the environment. It is also possible to make changes to more
subtle parameters that only environmental chemists can fully understand – or at least, they claim to be able to.
of risk to customers is through the SDS and where appropriate, the Exposure Scenario.
Even though substances over 1 tonne supply will need to be considered with an exposure scenario, lower volume hazardous
substances will still require an SDS in the same way as currently applies.
CSR does not need to be given to customers, but the ‘enhanced’ SDS must take into account the conclusions in considering
risk reduction recommendations.
format is still open for discussion, but the technical content of the CSR is effectively the same as the current risk assessment
requirements. However, it is proposed that the CSR will be prepared in two parts;
Part A is the conclusions and declarations that risk management measures are implemented and communicated and Part B that
is the main technical component.
needs to consider:
2 Manufacture and use patterns
3 Classification and labelling
4 Environmental fate assessment
5 Health hazard assessment
6 Physical hazard assessment
7 Environmental hazard assessment
8 Assessment of whether PBT* or vPvB
9 Exposure assessment
10 Risk characterisation
Bioaccumulative Toxic or very Persistent, very Bioaccumulative
source of hazard data will be the Chemical Safety Assessment (CSA) and the format for this will consider the environmental
hazard, the human health hazard and physico-chemical health hazard data as well as the vPvB potential. If vPvB, additional elements will need to consider exposure assessments and risk characterisation; if vPvB,
close control over supply is expected and it is possible that Authorisation will not be given.
needs to be considered in the light of the ES and the resulting comparison will provide the key to the risk assessment –
comparing hazard and exposure.
the ES, suppliers will need to liase closely with their customers to ensure that the scenario for exposure is realistic and
conversely, once prepared, the user must not deviate from conditions used for the ES.
For specialist uses, or if the use is considered confidential, the user will need to prepare an ES and perhaps even
a new CSR to cover their particular use.
of exposure data up and down the supply line is anticipated to be one of the more difficult activities facing industry. There are perceived to be many problems concerning confidentiality and data ownership,
but only industry can find answers to the communication problems. Downstream
users (DUs) can provide their own ES and CSR, but will need to report to the European Central Agency these uses in case the
Registration of the substance is itself compromised and new Authorisation is required.
guidance documents have been prepared under RIP 3.2 (REACH Implementation Project) and are published by the ECB (http://ecb.jrc/documents/reach). More guidance is expected over the coming months.
format of the SDS will change under REACH, but the basic 16-point format will remain.
However, the findings of the ES and CSR need to be communicated in various section of the SDS and it is important that
the risk reduction recommendations are consistent with the ES and CSR.
may also need to be supplied to the customer to provide more detailed information on safe handling and control. Sections relating to physico-chemical properties, toxicology and ecotoxicology must also be consistent
with the CSA that in turn has been used to prepare the CSR.
the job of the SDS remains the same, but under REACH, it is expected that there will more information to communicate at a
greater level. Chemical supply may also be linked to specific uses only and the
SDS must obviously make this clear.
the vast majority of non-hazardous products, there may be little real change in communication requirements.
Control and Authorisation
substances may be authorised only for specific uses that have been considered to represent an acceptable level of risk or
are considered to be of socio-economic benefit for a specific function. Restrictions
on Authorisation can be expected on substance considered to be CMR (Carcinogenic, Mutagenic or Toxic for Reproduction) or
are PBT or vPvB. It is possible that total restrictions are placed on certain
substances, as is currently enforced through specific Directives.
For all hazardous
substances, some level of risk management will be required and this is to be proposed in the CSR and communicated through
the SDS and ES.
Good risk management
of all chemicals is reliant on good communication – by informing those in contact with or responsible for the use of
chemical of hazards and then proposing mechanisms for control of exposure, risk reduction is possible. Exposure control must be proposed to reflect the hazard and good communication will allow judgement to
be made on the level of control required.