Toxicological Risk Assessment of Chemicals: A Practical Guide - Chapter 9 (end) ppt

9
Regulatory Standards Set
by Various Bodies
Regulat ory standards, or health-bas ed guidan ce values , in this chapte r denote d ‘‘guidan ce values, ’’
for exposur e to chemi cals in various medi a such as air, drink ing water, soil , and food are set by
vario us international , federal , and nationa l bodies . This chapte r will give an overview of the
develo pment of guidanc e values in general term s and presen t some examp les.
9.1 GUIDANCE VALUES: DEVELOPMENT
This section gives an overvi ew of the develo pment of guidance values in general term s.
Acco rding to the OECD=IPC S de finitions listed in Annex 1 (OECD 200 3):
Guidanc e Value is ‘‘Valu e, such as concent ration in air or water, which is deriv ed after
allocati on of the reference dose among the different possible media (routes) of exposur e. ’’
Combi ned exposur es from all media at thei r respec tive guidan ce values over a lifetime woul d be
expect ed to be without ap preciable health risk . The aim of a guidan ce value is to provi de
quantitat ive infor mation from risk asses smen t for risk manag ers to enable them to make decisions
concern ing the prote ction of human health.
Guidanc e values are de veloped from a stand ard such as, e.g., an Acce ptable=Tolerable Daily
Intake (ADI=TDI), and Reference Dose=Concentration (RfD=RfC). For threshold effects, the standard
is d erived by divi ding the No- Observed- Adve rse-Effect Level (NOA EL) or Lowes t-Obser ved-
Adve rse-Effect Level (LOAE L), or alternatively a Ben chmark Dos e (BMD ) for the critical effect
(s) b y an overall asses sment factor, descri bed in detail in Cha pter 5. Fo r non-thresho ld effects, the
stand ard is d erived by a qu antitative assessmen t, described in detai l in Chapter 6.
To the extent possible, guidan ce v alues shoul d re flect consideration of tota l exposur e to the
substance whether presen t in air, drinking water, soil , food, or other media. Guidance values should
be derived for a clearly defined exposure scenario, e.g., for ambient air, drinking water, and soil
based on the human exposur e facto rs presen ted in Section 7.3. It shoul d be recogni zed that there are
no internationa lly agreed stand ard values for human exposur e facto rs, and the examples presen ted in
Secti on 7.3 serve to illust rate the diff erences in exposur e facto rs provi ded by various exposur e facto r
docum ents. Such differences can have a great impa ct on the guidance values, and it is therefore
important that the most relevant and reliable exposure factors are used for the particular situation.
The development of guidance values for chemicals present in more than one environmental

medium will require the allocation of proportions of the tolerable intake to various media based on
information on relative proportion of total exposure from each of the media. If possible, estimation
of exposure should be based on concentrations in the environmental media including ambient air,
drinking water, soil, and food as well as consumer products. Unless there are age groups being more
sensitive or having widely differing exposure profiles, the intake from each of the media shoul d be
estimated for adults, e.g., for ambient air, drinking water, and soil based on the human exposure
factors presented in Section 7.3. If the data on concentrations of a substance in environmental media
are inconsistent or inadequate, exposure could be estimated based on models, which incorporate
as much data as possible on, e.g., production, use patterns, and physico-chemical properties.
ß 2007 by Taylor & Francis Group, LLC.
An examp le of an exposur e model to predict dist ribution in envir onmen tal media and esti mation of
the proportion of total exposur e by vario us route s from consum er product s is the EUSE S (S ection
7.2.4.3). It is imp ortant to recogni ze that the propor tions of total inta ke from vario us media may
vary, based on circu mstances.
It shoul d be noted that a source in one medi um may lead to addit ional inta ke from other routes,
e.g., for drink ing wat er, dermal and inhal ation exposur e may occur during a shower, and for soil,
exposur e would often b e both via ingestio n and dermal c ontact; when possi ble, such inta ke shoul d
also b e consi dered in the derivatio n of guidan ce values.
Total allo cations of less than 100% of the tole rable inta ke are recommend ed to account for, e.g.,
those medi a for whi ch exposur e has not been charact erize d, and cross-rout e exposur e. The propor -
tion of the total intake, which is not allocated, shoul d vary accordi ng to the adequacy of the
exposur e characte rization from all media.
The preci sion of the guidan ce value is dependen t upon the validit y and relia bility of the available
data. In addit ion to the impact on the guidanc e value from the choice of an exposur e facto r as
ment ioned above, there are often sources of uncertaint y in the derivatio n of the tolerable intake
(Secti on 5.12) and in thei r allocati on as a basis for the guidance v alues. The resulting guidance values
thus represen t a best estimat e based on the available data at the time of develo pment. The numer ical
value of a guidan ce value shoul d re fl ect the precision in its deriv ation, and shoul d usual ly be given to
only one signi fican t figure.
Gui dance values can be set for the general popula tion, occupat ional ly exposed popula tion, as

well as for suscep tible subgro ups. The approac h for sett ing guidanc e values in the ambient e nviron-
ment , i.e., ambi ent air, d rinking water, soil, food, and other media relates prima rily to long- term
exposur e of the general popula tion. Some degree of human varia bility is taken into account in the
asses sment factors appli ed in the derivatio n of the tolerable intak e (Chapte r 5). Where a u niquely
sensitive group forms a signi fican t proportion of the populatio n, the tole rable intake could be deriv ed
based on that group. In cases where the exposur e pro files of this subgro up and the general
popula tion are simil ar, the guidan ce values shoul d be based on the tolerable inta ke for the sensi tive
subgro up. If the exposur e pro fi les diff er, guidan ce values shoul d be calcul ated separa tely for the
subgro up and general populatio n based on their respec tive tolerable intakes and exposur e pro files, and
the more conservati ve va lues adopted . The approac h for setting gu idance values relating to intermi t-
tent , short-ter m (e.g., accidental), and occ upational exposures is basically similar to that for long-term
exposure although there might be other considerations to take into account.
9.2 GUIDANCE VALUES: EXAMPLES
Various international, federal, and national bodies set guidance values for ex posure to chemicals in
various media such as air, drinking water, soil, and food. This section will present some examples of
guidance values set by the WHO representing an international body, the US-EPA and the EU
representing federal bodies, and Denmark representing a national body.
9.2.1 WHO
Examples of guidance values develo ped by the WHO include ‘‘air quality guidelines’’ and ‘‘drink-
ing water guidelines,’’ and (in collaboration with the FAO) ‘‘maximum residue limits’’ (MRLs) for
pesticides and veterinary drugs and ‘‘maximum levels’’ for food additives.
9.2.1.1 Air Quality Guidelines
Recognizing the need of humans for clean air, the WHO Regional Of fice for Europe in 1987
published the first edition of the ‘‘Air Quality Guidelines for Europe’’ containing health risk
assessments of 28 chemical air contaminants (WHO 198 7). In 1993, air pollutants of special
environmental and health significance to countries of the European Region were identified by a
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WHO planni ng group, and 35 air pollutant s were selected to be incl uded in a second edition of the
Air Qualit y Guidelines , whi ch was publi shed in 2000 (WHO 2000). It is noted that relev ant EHC
docum ents (Section 3.6.1.1) wer e of great value with respect to the selec tion of pollu tions to be

included in the second edition of the Air Qual ity Guid elines (WH O 2000). The publi cation is
available via the WHO Regional Of fice for Europ e ’s Web site (WHO 2007 b).
The second edit ion of the Air Qual ity Gui delines for Euro pe (WHO 2000) comprises four
introduct ory chapters plus sectio ns on health risk evalua tion and guidelines of the variou s pollu tants.
The intr oducto ry Cha pter 1 of the Air Quality Guide lines sets the scene regarding air quality
issues, states the natur e of the air quali ty guidel ines, and de scribes the procedu res used in the
updating and revision proces s. In the following text , the most essent ial informat ion in the contex t of
this book is presen ted.
The second edition is limited to summari es o f the data on whi ch the guidelines are based; the
full backgro und evalua tion shoul d becom e progre ssiv ely avail able on the WHO Regional Of fice for
Europe ’ s Web site (WH O 2007b). As in the fi rst e dition, detai led referencing of the relev ant
literat ure has been provi ded with indicati ons of the periods cov ered by the reviews of individua l
pollutant s.
The primary aim of the guidelines is to provi de a basis for protectin g public healt h from advers e
effects of air poll ution and for elimin ating, or reducing to a min imum, those contamina nts of air that
are known or like ly to be hazardo us to human healt h and well-b eing. The guidelines are intended to
provi de backgro und infor mation and guidan ce to g overnments in makin g risk manag ement
decis ions, particula rly as a basis for sett ing stand ards or limit values for air contam inants.
The guidelines are not restrict ed to a numerical value below whi ch exposur e for a given perio d
of time does not const itute a signi fi cant health risk ; they also incl ude any kind of recom mendation or
guidan ce in the relev ant field. Numerical values either indi cate the airbo rne concent ration of a
chemica l combi ned wi th exposur e times at whi ch no advers e effect is expecte d in terms of
noncarc inogen ic endpoi nts, or they provide an estimat e of lif etime cancer risk arising from those
substanc es that a re proven human carcinogen s or carci nogens wi th at least limited eviden ce of
human carci nogeni city. It is point ed out that the risk estimates for carcinogens do not indi cate a safe
level, but they are presen ted so that the carci nogeni c potencies of diff erent carcinog ens can be
compa red and an asses sment of overall risk made. The guidel ines, including numer ical values , are
further addres sed in the intr oducto ry Cha pter 3 of the Air Qual ity Guideline s (WH O 2000).
When numerical guideline v alues are given, these values are not standa rds in themselv es.
Before trans forming them into legal ly binding standards, the g uideline values must be consi dered

in the contex t of prevailin g exposur e levels, technical feasi bility, source contr ol meas ures, abate-
ment stra tegies, and socia l, econom ic, and cult ural con ditions; this is furth er add ressed in the
introduct ory Chapter 4 of the Air Qualit y Gui delines (WHO 2000 ).
It is stat ed that inhal ation of an air poll utant in concent rations and for exposur e times below a
guideline value will not ha ve adverse e ffects on health; howe ver, complianc e with recom menda tions
regard ing guidel ine v alues does not guarant ee the absolute exclusion of effects at levels below such
values . As an examp le it is mentioned that highly sensiti ve groups such as those imp aired by
concurr ent disea se or other p hysiologi cal limitati ons may be affected at or near concent rations
referred to in the guideline values . Health effect s at or below guideline values may also resul t from
combine d exposur e to various chemicals or from exposur e to the same chemi cal by mul tiple route s.
It has been agreed with the EU Comm ission that the fi nal d rafts of the revised WHO guideline
docum ents woul d provi de a starting po int for discu ssions by the Commiss ion ’s working groups
aiming at sett ing legally binding limit values for air q uality in the EU, see Section 9.2.4.1.
The introduct ory Chapter 2 of the Air Quality Guidelines (WHO 2000) gives a very detailed and
compr ehensive descri ption of the crit eria used in estab lishing the guidel ine values including criteria
for selec tion of NOA EL=LOA EL, advers e effect , benchm ark approac h, and uncertaint y facto rs.
These criteria are compa rable to the principle s outlined in Chapter s 4 and 5 in this book. There are
also criteria for selection of averaging times and for consideration of sensory effects (malodorous
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proper ties at conc entration s far below those at which toxi c effect s occur) . In addition, there are
criteria for carci nogeni c endpoi nt incl uding qualitat ive assessmen t of carci nogeni city, qua ntitative
asses sment of carcinogeni c potenc y, quantitat ive asses smen t of carcinogen icity b ased on human
data, risk estimat es from animal cancer bioas says, and inte rpretati on o f risk estimates; these crite ria
are compa rable to the princ iples outl ined in Cha pter 6 in this book. It is speci fically point ed out that
durin g the prepar ation of this second edition of the g uidelines , attentio n was paid to de fining speci fic
sensi tive subgro ups in the popula tion.
WHO global air quality gu idelines are available for the following air poll utants: parti culate
mat ter, ozone, nitroge n dioxide, and sulf ur dioxi de. The latest revis ion, which was p ublished
in 200 5, subst antially lowered the recom mende d limit s of pa rticulate matter, ozone, and sulfur
dioxi de. The publicatio n is a vailable via the WHO Reg ional Of fice for Europ e ’s Web site

(WH O 2007b).
9.2.1. 2 Drin king-Water Guide lines
The WHO published the first and second editions of the ‘‘ Guidelin es for Drinki ng-wate r Qualit y ,’’
in three volum es, in 1984 –1985 and in 1993 –1997, respec tive ly. The fi rst edit ion contains health
risk asses sments of 36 inorg anic const ituents and physical pa rameters , 27 organic compo unds, 30
pesticide s, 4 disinfect ants, 5 disinfect ant by-products , and 6 other chlorinat ion by-pro ducts. The
second edition contai ns healt h risk assessmen ts of 6 inorg anic constitu ents (updat ed), 3 organi c
compo unds (1 new, 2 update d), 10 pesticide s (7 new, 3 update d), and 1 disinfect ant by-pro duct
(new ). A third edition of Volume 1 was published in 200 4. The Gui delines are k ept u p to date by a
‘‘ rolling revision ’’ and a fourt h edition is schedu led for 2008. The publicati ons are avail able to the
publi c via the WHO Water Sanitatio n and Heal th Web site (WHO 2 007a).
Vol ume 1 ‘‘Recomm endations ’’ addres ses requi reme nts to ensure drinking-wat er safety, includ-
ing min imum procedu res and speci fic guidel ine values, and how those requi reme nts a re intended to
be used. The volum e also describes the approac hes used in deriving the guidelines , including
guidel ine values . It includes fact sheet s on signi ficant microbial and chemical hazards . Cha pter 12
provi des the fact sheet s for the indi vidual ch emical contamina nts evalua ted. Fo r those contam inants
for which a guideline value has been estab lished, the fact sheet s inclu de a brief toxi cological
overvi ew of the chemi cal, the basis for guidel ine derivation, treat ment achievabil ity, and analyt ical
limit of detection.
Volume 2, ‘‘Health Criteria and other Supporting Information,’’ explains how guideline values
for the contaminants are to be used, defines the criteria used to select the various chemical, physical,
microbiological, and radiological contaminants included, describes the approaches used in deriving
guideline values, and presents, in the form of brief monographs, critical reviews and evaluations of
the effects on human health of the substances or contaminants examined. The introductory chapter
of Volume 2, second edition (WHO 1996), sets the scene regarding drinking-water quality issues,
gives some general considerations, states the nature of the drinking-water quality guidelines, and
describes the criteria for the selection of health-related drinking-w ater contaminants. In the follow-
ing text, the most essential information in the context of this book is presented.
The primary aim of the Guidelines for Drinking-water Quality is the protection of public health.
The guidelines are addressed primarily to water and health regulators, policymakers and their

advisors and intended to be used as a basis for the development of national standards that may
ensure the safety of drinking-water supplies through the elimination, or reduction to a minimum
concentration, of constituents of water that are known to be hazardous to health. It is pointed out that
the guideline values recommended are not mandatory limits as, in order to define such limits, it is
necessary to consider the guideline values in the context of local or national environmental, social,
economic, and cultural conditions.
It is noted that the problems associated with chemical constituents of drinking water arise
primarily from their ability to cause adverse health effects after prolonged periods of exposure, and
ß 2007 by Taylor & Francis Group, LLC.
it is point ed out that of particula r concern are contamina nts that hav e cumulati ve toxic proper ties
such as heavy met als and carcinogeni c subst ances. It is also pointed out that the use of chemical
disinfect ants in wat er treatmen t u sually resul ts in the formati on of chemical by-produ cts, some of
which are potential ly hazardo us.
Guideli ne values have been set for potent ially hazardo us wat er const ituents an d provi de a basis
for assessing drink ing-water quali ty. A guidel ine value repres ents the concent ration of a const ituent
that doe s not resul t in any signi ficant risk to the health of the consumer over a lif etime of
consum ption. However , it is empha sized that the guidel ine values should not be regard ed as
implyi ng that the quali ty of drink ing water may be degrade d to the recom mende d level . It is point ed
out that short-ter m deviations above the guidel ine values do not necess arily mean that the water is
unsui table for consumpti on. The amoun t by which, and the perio d for whi ch, any guideline value
can be exceeded without affecting public healt h depend s upon the speci fic substa nce invol ved.
In some instances, provision al guidel ine values have been set for constitu ents for whi ch there is
some eviden ce of a potent ial hazard but wher e the avail able informat ion on health effects is limit ed.
Provis ional guidel ine values have also been set for subst ances for whi ch the calcul ated guideline
value would be below the practical quanti ficati on level, or below the level that can be achiev ed
throu gh pract ical treatmen t methods, as well as for certa in subst ances when it is likely that guideline
values wi ll be exc eeded as a result of disin fection procedu res.
It is stated that thousands of c hemicals have been ident i fied in drinking-w ater suppl ies around
the world, many in extre mely low concent rations. The chemi cals selec ted for the develo pment of
guideline values includ e those consi dered potentially hazardo us to human health, those detect ed

relativel y freque ntly in drinking water, and those detect ed in relatively high concent rations.
Cha pter 12 of Volume 2, second edit ion (WH O 1996), gives a detailed and compr ehensi ve
descripti on of the principle s used in estab lishing the guidel ine values .
The asses smen t of the toxicit y of drink ing-wat er contamina nts has been made on the basis of
published reports from the ope n literat ure, informat ion subm itted by go vernments and other inter-
ested p arties, and unpublishe d propri etary data. In the develo pment of the guidel ine values , existing
internati onal approac hes to developing guidel ines were careful ly consi dered. Previo us risk a ssess-
ments develo ped by the WHO=IPC S in EHC monog raphs (see Section 3.6.1.1), IARC (see Secti on
3.6.1.2), JMPR (see Section 3.6.1.3), and JECFA (see Secti on 3.6.1.3) were reviewed. The se
asses sments were relied upon except where new infor mation justi fied a reassessm ent. The quality
of new data was critically evaluated prior to their use in risk assessmen t.
The section on de rivation of guidel ine values using a tolerable daily inta ke (T DI) incl udes
criteria for derivatio n of a TDI from a NOA EL o r LOA EL by applicati on of uncertaint y factors;
these crit eria are comparable to the principle s ou tlined in Chapter s 4 and 5 in this boo k. The
guideline value is then derived from the TDI as follows:
GV ¼ [TDI  bw  P]=C
where
bw ¼ body weight (60 kg for adults, 10 kg for children, 5 kg for infants)
P ¼ proportion of the TDI allocated to drinking water
C ¼ daily drinking-water consumption (2 L for adults, 1 L for children, 0.75 L for infants)
In many cases, the intake of a chemical from drinking water is small in comparison with that from
other sources such as food and air. Guideline values derived using the TDI approach take into
account exposure from all sources by allocating a percentage of the TDI to drinking water. When
possible, data concerning the proportion of total intake normally ingested in drinking water (based
on mean levels in food, air, and drinking water) or intakes estimated on the basis of consideration of
physical and chemical properties were used in the derivation of the guideline values. Where such
information was not available, an arbitrary (default) value of 10% for drinking water was used.
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This defaul t v alue was considered, in most cases, to be suf ficient to account for additional routes of
inta ke, i.e., inhalati on and derm al absorp tion of contam inants in water.

The re is also a section on deriv ation of guidel ine va lues for potent ial carci nogens; the criteria in
this section are compa rable to the princ iples outlined in Chapter 6 in this book.
Vol ume 3 ‘‘Su rveillanc e and contr ol of comm unity suppl ies ’’ contai ns recom mendation s and
infor mation concern ing what needs to be done in small comm unities, particula rly in deve loping
countr ies, to safeguard their water suppl ies.
9.2.1. 3 Foo d
The Codex Alimentar ius Commiss ion was creat ed in 1963 by FAO and WHO to develo p food
stand ards, guidel ines, and relat ed text s such as codes of practice under the Joint FAO=WHO Food
Standar ds Program. The mai n purpos es of this Program are to protect the healt h o f the
consum ers and to ensure fair trade practices in the food trade, and to promote the coordi nation of
all food standards wor k un dertaken by inte rnational governm ental and nongover nmental o rganiza-
tion s (CA 2007).
The Codex Al imentarius is a colle ction of stand ards, codes of practice, guidel ines, and other
recom menda tions. Some of these texts are very general, and some are very speci fi c. Some deal with
detai led requi rements related to a food or group of foods; others deal with the operation and
manag ement of product ion proces ses or the operat ion of governm ent regul atory systems for food
safet y and consum er p rotection .
The main FAO=WHO expert bodies incl ude the Joint FAO=WHO Expert Comm ittee on Food
Additi ves (JECFA) , the Joint FAO=W HO Meetings on Pesticide Residue s (JMPR) , and the Joint
FAO= W HO Exp ert Meetings on Micr obiologic al Risk Assessme nt (JEMRA ). Cod ex Alim entar ius
provi des lists of MRLs for pesti cides a nd veterinary drugs, and maxi mum level s for food additives .
The Joint FAO=WHO Expert Comm ittee on Food Addi tives (JECFA) was estab lished in 1955
to consi der chemical, toxi cological, and other aspects of contamina nts and residue s of veterinary
drugs in foods for human consum ption. The Cod ex Committ ee on Food Addi tives and Contamin-
ants and the Code x Comm ittee on Residue s of Veterin ary Drug s in Fo ods identify food additives ,
contam inants, and veter inary drug residues that shoul d recei ve priority evalua tion and refer them to
JECFA for assessmen t before incor porating them into Code x stand ards.
The Joint FAO=WHO Meet ings on Pesti cide Res idues (JMPR) began wor k in 196 3 foll owing a
decis ion that the Codex Alim entarius Comm ission should recommend MRLs for pesticide s and
envir onmen tal contamina nts in speci fic food p roducts to ensure the safety of foods containing

resi dues. It was also decide d that JMPR shoul d recom mend met hods of samp ling and analysis.
The re is close coopera tion betw een JMPR and the Codex Com mittee on Pesticide Residue s
(CCPR) . CCPR identi fies those substances requi ring priority evalua tion . After JMPR evalua tion,
CCPR discu sses the recommend ed MRL s and, if they are accept able, forwards them to the
Comm ission for adopti on as Cod ex MR Ls.
The Joint FAO=WHO Expert Meet ings on Microbiol ogical Risk Ass essment (JE MRA) began
wor k in 2000 to develo p and provide advice to the Cod ex Alim entarius Comm ission on mic robio-
logi cal aspect s of food safety. In addit ion to provi ding risk asses sments, JE MRA develo ps guidan ce
on related areas such as data coll ection and the applica tion of risk asses smen t. JEMRA wor ks most
close ly with the Cod ex Comm ittee on Food Hygiene, but has also provi ded advice to other Codex
comm ittees, such as the Comm ittee on Fish and Fisher y Produc ts.
9.2.2 UNITED STATES
The U.S. Env ironment al Protec tion Agen cy (US-E PA) is the federal agency respon sible for
regul ating the level of contamina nts in ambient a ir (Section 9.2.2.1), drinking water (Secti on
9.2.2.2), and soil (Section 9.2.2.3) while the U.S. Food and Drug Adm inistration (US-F DA) is
the federal agency respon sible for regul ating the level of contam inants in food (Section 9.2.2.4).
ß 2007 by Taylor & Francis Group, LLC.
9.2.2.1 Air
The Clean Air Act (CAA), amended in 1970 and in 1990 (US-EPA 1990), is the federal law under
which the US-EPA sets limits for air pollutants anywhere in the United States. This ensures uniform
basic health and environmental protection across the country. The law allows individual states to
have stronger pollution controls, but states are not allowed to have weaker pollution controls
than those set for the whole country. The states do much of the work to carry out the Act
(US-EPA 2007a).
States have to develop state implementation plans (SIPs) that explain how each state will do its
job under the Clean Air Act. A state implementation plan is a collection of the regulations a state
will use to clean up polluted areas. The states must involve the public, through hearings and
opportunities to comment, in the development of each state implementation plan.
US-EPA must approve each SIP, and if a SIP is not acceptable, US-EPA can take over enforcing
the Clean Air Act in that state.

The U.S. government, through US-EPA, assists the states by providing scientific research,
expert studies, engineering designs, and money to support clean air programs.
US-EPA refers to chemi cals that cause serious health and environmental hazards as hazardous
air pollutants (HAPs) or air toxics. The 1970 Clean Air Act gave US-EPA authority to list air toxics
for regulation and then to regulate the chemicals. The agency listed and regulated seven chemicals
through 1990. The 1990 Act includes a list of 189 hazardous air pollutants selected by Congress on
the basis of potential health and=or environmental hazard; US-EPA must regulate these listed air
toxics. The 1990 Act allows US-EPA to add new chemicals to the list as necessary.
US-EPA develops regulations, MACT (Maxi mum Achievable Control Technology) standards,
requiring sources to meet specific emission limits that are based on emission levels already being
achieved by many similar sources in the country. Then US-EPA appli es a risk-based approach to
assess how these technology-based emission limits are reducing health and environmental risks.
Based on this assessment, US-EPA may implement additional standards to address any significant
remaining, or residual, health or environmental risks.
US-EPA is developing an air toxics risk assessment (ATRA) reference library for conducting air
toxics analyses at the facility and community-scale. This library provides information on the
fundamental principles of risk-based assessment for air toxics and how to apply those principles
in different settings as well as strategies for reducing risk at the local level.
A Technical Resource Manual is available, which gives comprehensive guidance on the risk
assessment process (US-EPA 2004).
9.2.2.2 Drinking Water
The Safe Drinking Water Act (SDWA) is the main federal law that ensures the quality of the
drinking water (US-EPA 2007b).
The SDWA was originally passed by Congress in 1974 to protect public health by regulating the
nation’s public drinking-water supply. The law was amended in 1986 and 1996 and requires many
actions to protect drinking water and its sources: rivers, lakes, reservoirs, springs, and groundwater
wells. SDWA does not regulate private wells, which serve fewer than 25 individuals. SDWA
authorizes the US-EPA to set national health-based standards for drinking water to protect against
both naturally occurring and man-made contaminants that may be found in drinking water.
US-EPA, States, and water systems then work together to make sure that these standards are met.

US-EPA sets national standards for tap water, whi ch help ensure consistent quality in the water
supply. US-EPA prioritizes contaminants for potential regulation based on risk and how often they
occur in water supplies. Certain water systems are monitored for the presence of contaminants for
which no national standards currently exist and collect information on their occurrence. US-EPA
sets a health goal based on risk, including risks to the most sensitive people, e.g., infants, children,
pregnant women, the elderly, and the immuno-compr omised. US-EPA then sets a legal limit for the
ß 2007 by Taylor & Francis Group, LLC.
contaminant in drinking water or a required Treatment Technique (TT). This limit or TT is set to be
as close to the health goal as feasible. US-EPA also performs a cost–benefit analysis and obtains
input from interested parties when setting standards.
US-EPA uses the following steps to set enforceable, health-based drinking-water standards:
.
Determine whether a contaminant should be regulated based on peer-reviewed science,
including data on: how often the contaminant occurs in the environment; how humans are
exposed to it; and the health effects of exposure (particularly to vulnerable subpopula-
tions).
.
Set a Maximum Contaminant Level Goal (MCLG) (the level of a contaminant in drinking
water below which there is no known or expected health risk. MCLGs allow for a margin
of safety). These goals take into account the risks of exposure for certain sensitive
populations, such as infants, the elderly, and persons with compromised immune systems.
These goals are not enforceable levels because they do not take available technology
into consideration, and therefore are sometimes set at levels which public water systems
cannot meet.
.
Propose an enforceable standard in the form of a Maximum Contaminant Level (MCL)
(the maximum amount of a contaminant allowed in water delivered to a user of any public
water system) or a treatment technique (TT) (required procedure or level of technological
performance set when there is no reliable method to measure a contaminant at very low
levels). MCLs are set as close to MCLGs as feasible, considering available technology and

cost. Examples of rules requiring TTs are the Surface Water Treatment Rule (requires
disinfection and filtration) and the Lead and Copper Rule (requires optimized corrosion
control). Water samples that contain lead or copper exceeding the action level trigger
additional treatment or other requirements that a water system must follow. Required
testing (monitoring) schedules are part of the enforceable standard. After determining a
proposed MC L or TT that is as close to the MCLG as possible based on affordable
technology, US-EPA must complete an economic analysis to determine whether the
benefits of that standard justify the costs. If not, US-EPA may adjust the MCL for a
particular class or group of systems to a level that maximizes health risk reduction benefits
at a cost that is justified by the benefits. US-EPA may not adjust the MCL if the benefits
justify the costs to large systems and small systems that are unlikely to receive variances.
.
Set an enforceable MCL or TT. After considering comments on the proposed standard and
other relevant information, US-EPA makes final an enforceable MCL or TT, including
required testing and reporting schedules. States are authorized to grant variances from
standards for systems serving up to 3,300 people if the systems cannot afford to comply
with a rule (through treatment, an alternative source of water, or other restructuring) and
the systems install US-EPA approved variance technology. States can grant variances to
systems serving 3,301–10,000 people with US-EPA approval. SDWA does not allow
small systems to have variances for microbial contaminants. Under certain circumstances
exemptions from standards may be granted to allow extra time to seek other compliance
options or financial assistance. After the exemption period expires, the public water system
must be in compliance. The terms of variances and exemptions must ensure no unreason-
able risk to public health.
9.2.2.2.1 The Contaminant Candidate List
The 1996 Amendments to SDWA require that every 5 years US-EPA establish a list of contamin-
ants which are known or anticipated to occur in public water systems and may require future
regulations under SDWA. The list is developed with significant input from the scientific community
and other interested parties. After establishing this contaminant candidate list, US-EPA identifies
contaminants, which are priorities for additional research and data gathering. US-EPA uses this

ß 2007 by Taylor & Francis Group, LLC.
information to determine whether or not a regulation is appropriate and this process is repeated for
each list, every 5 years.
In order to support this decision making, US-EPA has also established a National Contaminant
Occurrence Database (NCOD), which stores data on the occurrence of both regulated and unregu-
lated contaminants. US-EPA is also required to list and develop regulations for moni toring certain
unregulated contaminants. This monitoring data will provide the basis for ident ifying contaminants
that may be placed on future Contaminant Candidate Lists and support the US-EPA Administrator’s
decisions to regulate contaminants in the future.
9.2.2.3 Soil
The U.S. National Environmental Policy Act of 1969 required careful analysis of the consequences
of any federally funded project. The Resource Conservation and Recovery Act (RCRA) of 1976
established guidelines for handling, transport, and hauling of hazardous materials, such as required
in cleanup of soil contaminants. The Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) of 1980 established, for the first time, strict rules on legal liability for soil
contamination. CERCLA stimulated identification and cleanup of thousands of contaminated land
sites, and consequently raised awareness of property buyers and sellers to make soil contamination a
focal issue of land use and management practices (US-EPA 2007c).
9.2.2.3.1 The Comprehensive Environmental Response, Compensation, and Liability Act
The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), com-
monly known as Superfund, was enacted by the U.S. Congress on 11 December 1980. CERCLA
created a tax on the chemical and petroleum industries and provided broad Federal authority to
respond directly to releases or threatened releases of hazardous substances that may endanger public
health or the environment. Over 5 years, $1.6 billion was collected and the tax went to a trust fund
for cleaning up abandoned or uncontrolled hazardous waste sites (US-EPA 2007c).
CERCLA established prohibitions and requirements concerning closed and abandoned hazard-
ous waste sites; provided for liability of persons responsible for releases of hazardous waste at these
sites; and established a trust fund to provide for cleanup when no responsible party could be
identified.
CERCLA authorizes two kinds of response actions: Short-term Rem ovals, where actions may be

taken to address releases or threatened releases requiring prompt response; and Long-term Remedial
Response Actions, that permanentl y and significantly reduce the dangers associated with releases or
threats of releases of hazardous substances that are serious, but not immediately life threatening.
These actions can be conducted only at sites listed on US-EPA’s National Priorities List (NPL).
CERCLA also enabled the revision of the U.S. Nationa l Contingency Plan (NCP). The NCP
provides the guidelines and procedures needed to respond to releases and threatened releases of
hazardous substances, pollutants, or contamina nts. The NCP also established the NPL.
CERCLA was amended by the Superfund Amendments and Reauthorization Act (SARA) on
17 October 1986.
9.2.2.3.2 The Superfund Program
The goal of the Superfund progra m is to clean up uncontrolled hazardous waste sites that pose
unacceptable risks to human health and environment in a manner that restores these sites to uses
appropriate for nearby communities. As already mentioned, the program was authorized under the
CERCLA of 1980 (US-EPA 2007c).
The Soil Screening Guidance, Technical Background Document (US-EPA 1996a) provides the
technical background for the development of methodologies described in the Soil Screening
Guidance: User’s Guide (US-EPA 1996b), along with additional information useful for soil
screening. Together, these documents define the framework and methodology to develop
soil screening levels (SSLs) for chemicals commonly found at Superfund sites.
ß 2007 by Taylor & Francis Group, LLC.
SSLs are risk -based concent rations deriv ed from standardiz ed equati ons combinin g exposur e
infor mation assum ptions with US-EP A toxi city data. Fo r the ingestio n, derm al, and inhal ation
pathwa ys, toxicit y c riteria are used to de fi ne an accept able level of contamina tion in soil, based
on a o ne-in-a-m illion (10
À 6
) indi vidual excess cancer risk for carcinogens and a Hazard Quot ient
(HQ) of 1 for noncarc inogen s. The hazard quotient is de fine d as the ratio of an exposur e esti mate
over the Ref erence Dos e o r Con centratio n (Secti on 5.1), i.e., HQ ¼ Exp osure=(RfD or RfC).
9.2.2. 4 Foo d
The US-FDA is the federal agenc y respon sible for regul ating the level of contam inants in food

(US- FDA 2007). The US-FDA establishe s ‘‘ action level s ’’ for poiso nous or deleterio us substances
to control levels of contam inants in human food and anim al feed.
Act ion level s and tolerances are estab lished based on the unavoi dabilit y of the p oisonous or
delet erious subst ances and do not represent perm issible levels of contam ination where it is avoid-
able. The blendi ng of a food or feed containing a substance in excess of an action level or tolerance
with anothe r food or feed in order to lower the concent ration of a con taminant is not perm itted, and
the final product resultin g from blending is unlawful , regard less of the level of the contam inant.
Act ion level s and tole rances represent limits a t or above which the US-FDA will take legal
acti on to remo ve product s from the mark et. Whe re no established a ction level or tole rance exists,
the US-FD A may take legal action against the product at the minimal detectable level of the
contam inant.
The action level s are establis hed and revise d according to crit eria speci fied in Title 21, Code of
Federal Regulat ions, Parts 109 and 509 and are revoked when a regulatio n establish ing a tolerance
for the same subst ance and use becom es effective.
Wit h respec t to veter inary medicines , the US-FDA establis hes tolerances to include a safety
facto r to assure that the drug will have no harm ful effects on consum ers of the food product. The
US-FD A first deter mines the level at which the drug doe s not produce any meas urable effect in
labor atory animals. From this, the US-FDA determin es an accept able daily intake (ADI), and the
drug tolerance and withdr awal times are then deter mined so that the con centratio ns of drug residues
in edible tissues are below the ADI. Depe nding on the drug, ‘‘safet y facto rs ’’ of betwee n 100-fo ld to
2000-f old a re incl uded in the calcul ations used to set the tolerances .
9.2.3 E UROPEAN UNION
9.2.3. 1 Air
Since the early 1970s, the Eur opean Union (EU) has been working to improve air quali ty by
contr olling emissi ons of harmful substances into the atmospher e, improvi ng fuel quality, and
by integrati ng en vironment al prote ction requi rements into the trans port and energy secto rs.
Thr ough EU legi slation, major air poll utants have been regul ated. For examp le, throu gh an EU
Directi ve (EC 1999), the EU has estab lished limit values for concent rations of sulfur dioxi de,
nitrogen dioxide and nitrogen oxides, particulate matter and lead, as well as alert thresholds for
concentrations of sulfur dioxide and nitrogen oxide, in ambient air. Member States must take

the measures necessary to ensure that concentrations of the pollutants in ambient air do not exceed
the limit values.
The EU’s Sixth Environment Action Programme (EAP), ‘‘Environment 2010: Our future, Our
choice,’’ includes Environment and Heal th as one of the four main target areas requiring greater
effort. Air pollution is one of the issues highlighted in this area. The Sixth EAP aims to achieve
levels of air quality that do not result in unacceptable impacts on, and risks to, human health and the
environment.
The EU is acting at many levels to reduce exposure to air p ollution: through EC legislation,
through work at international level to reduce cross-border pollution, through cooperation with
ß 2007 by Taylor & Francis Group, LLC.
sectors responsible for air pollution, through national, regional authorities and NGOs, and through
research. The Clean Air for Europe (CAFE) initiative has led to a thematic strategy setting out the
objectives and measures for the next phase of European air quality policy.
9.2.3.1.1 Clean Air for Europe
Clean Air for Europe (CAFE) was launched in March 2001 (CAFE 2007). CAFE is a program of
technical analysis and policy development, which supported the development of the Thematic
Strategy on Air Pollution under the Sixth EAP. The EU Commission adopted the Thematic Strategy
in September 2005.
The press release stated
The European Commission today proposed an ambitious strategy for achieving further significant
improvements in air quality across Europe. The Thematic Strategy on air pollution aims by 2020 to
cut the annual number of premature deaths from air pollution-related diseases by almost 40% from the
2000 level. It also aims to substantially reduce the area of forests and other ecosystems suffering damage
from airborne pollutants. While covering all major air pollutants, the Strategy pays special attention to
fine dust, also known as particulates, and ground-level ozone pollution because these pose the greatest
danger to human health. Under the Strategy the Commission is proposing to start regulating fine airborne
particulates, known as PM
2.5
, which penetrate deep into human lungs. The Commission also proposes to
streamline air quality legislation by merging existing legal instruments into a single Ambient Air Quality

Directive, a move that will contribute to better regulation.
The proposed Directive (the CAFE Directive) is the Directive on Ambient Air Quality and
Cleaner Air for Europe (EC 2005).
9.2.3.2 Drinking Water
The Drinking Water Directive (EC 1998), concerns the quality of water intended for human
consumption. The objective of the Drinking Water Directive is to protect the health of the
consumers in the EU and to make sure the water is wholesome and clean (free of unacceptable
taste, odor, color) and that it has a pleasant appearance (EC 2007a).
The Drinking Water Directive sets standards for the most common substances (so-called
parameters) that can be found in drinking water. In the Drinking Water Directive a total of 48
microbiological and chemical parameters must be monitored and tested regularly. In principle WHO
guidelines for drinking water are used as a basis for the standards in the Drinking Water Directive.
EU Member States must transpose the Drinking Water Directive into their own national legisla-
tion. The Member States can include additional requirements, e.g., regulate additional substances that
are relevant within their territory or set higher standards. But Member States are not allowed to set
lower standards as the level of protection of human health should be the same within the whole EU.
Member States have to monitor the quality of the drinking water supplied to their citizens and
this has to be done mainly at the tap inside private and public premises. Also the quality of drinking
water used in the food production industry has to be monitored to make sure it complies with the EU
standards. Member States report at three yearly intervals the monitoring results to the European
Commission.
The Commission assesses the results of water quality monitoring against the standards in the
Drinking Water Directive. After each reporting cycle the Commission produces a synthesis report,
which summarizes the quality of drinking water and its improvement at a European level. The
synthesis reports are available to the public (EU 2007).
9.2.3.3 Soil
An EU Soil Framework Directive is presently being developed. The EU has decided to adopt a
Thematic Strategy on Soil Protection as part of its aim of protection and preservation of natural
resources. A proposal for this is being finalized in 2006 (EC 2007b).
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The Strategy will comprise three elements:
.
A Communication laying down the principles of Community Soil Protection Policy
.
A Legislative proposal for the protection of soil - A Soil Frame work Directive
.
An analysis of the environmental, economic, and social impacts of the proposals
The proposed EU Soil Framework Directive will include the following main objectives:
.
Implementation of common principles
.
Future prevention of soil degradation
.
Conservation of soil functions
.
Protection of sustainable land use
9.2.3.4 Food
9.2.3.4.1 The European Food Safety Authority
The European Food Safety Authority (EFSA), based in Parma, Italy, since 2005 is the keystone of
EU risk assessment regarding food and feed safety.
EFSA was legally established by a European Parliament and Council Regulation adopted
in 2002 following a series of food scares in the 1990s including the Bovine Spongiform Encephalo-
pathy and dioxins scandals, which undermined consumer confidence in the safety of the food chain
(EFSA 2007).
The responsibility for risk assessment is clearly separated from that of risk management. While
EFSA advises on possible risk related to food safety, the responsibility for risk management lies
with the EU political institutions (European Commission, European Parliament, and the Council,
i.e., EU Member States). It is the role of the EU institutions, to propose and adopt legislation as well
as regulatory and control measures when and where required, taking into account EFSA’s advice as
well as other considerations. With respect to chemicals, EFSA assesses food additives, flavorings,

processing aids and mat erials in contact with food, additives and products or substances used
in animal feed, plant health, plant protection products and their residues, and contaminants in the
food chain (EFSA 2007). The basic principles of EU legislation on contaminants in food are
that food containing a contaminant to an amount unacceptable from the public health viewpoint
and in particular at a toxicological level, shall not be placed on the market, contaminant levels shall
be kept as low as can reasonably be achieved following recommended good working practices, and
maximum levels must be set for certain contaminants in order to protect public health.
Maximum residue levels in certain foods are set for the following contaminants: nitrate, myco-
toxins (aflatoxins, ochratoxin A, patulin, deoxynivalenol, zearalenone, fumonisins, T’-2 and HT-2-
toxin), metals (lead, cadmium, mercury, inorganic tin), 3-MCPD (3-monochloro-propane-1 ,2-diol),
dioxins and PCBs, and polycyclic aromatic hydrocarbons (benzo(a)pyrene) (EC 2007c).
9.2.3.4.2 Residues of Veterinary Medicines in Food
The European Medicines Agency (EMEA) is a decentralized body of the EU with headquarters in
London. The EMEA began its activities in 1995, when the European system for authorizing
medicinal products was introduced, providing for a centralized and a mutual recognition procedure.
The EMEA has a role in both, but is primarily involved in the centralized procedure. Where the
centralized procedure is used, companies submit one single marketing authorization application to
the EMEA. A single evaluation is carried out through the Committee for Medicinal Products for
Human Use (CHMP) or Committee for Medicinal Products for Veterinary Use (CVMP). If the
relevant Committee concludes that quality, safety, and efficacy of the medicinal product are
sufficiently proven, it adopts a positive opinion. This is sent to the Commission to be transformed
into a single market authorization valid for the whole of the EU (EMEA 2007).
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The CVMP is respon sibl e for prepar ing the Agen cy ’ s opini ons on a ll quest ions concern ing
veter inary medicinal products, in accordan ce with Regulat ion (EC) No. 726=2004 (EC 20 04).
A core activity of the CVMP is the estab lishmen t of MR Ls of veter inary medicinal product s
perm issible in food produce d by or from animals for human consumpti on, incl uding dairy
product s, meat , honey, etc. The se limits must be estab lished for all pharm acolog ically active
substanc es contained in a medi cinal product before the product can be granted a marketin g
author ization.

9.2.4 DENMARK
The p rocedure for sett ing health-bas ed quality crit eria in Denmark is descri bed brie fl y, to illustrate
the use of international princ iples in national chemicals regulatio n.
In Denm ark, healt h-base d quali ty criteria are set for chemical subst ances in a mbient air,
drinking wat er, and soil according to principle s laid down in a guidance docum ent from the
Danish Environmental Protection Agency (D-EPA 2006). These principles are for threshold
effects compa rable to the princ iples outlined in Cha pters 4 and 5 in this book, and for non-thresho ld
effects in Cha pter 6.
The health-based quality criteria are derived for the relevant media (ambient air, drinking water,
soil) by dividing the TDI with a standard exposure factor for this media.
The following general calculation method is used:
QC
asw
¼
TDI Á V Á f
e
asw
where
QC
asw
is the qu ality criterion for air, soil, or drink ing water
TDI is the tolerable daily intake expres sed as mg=kg bw=day
V is the body wei ght (bw ) in kg
f is the allo cation facto r, i.e., the fract ion of the TDI, which is allocated to e xposure from air,
soil, or drink ing wat er (Secti on 9.1)
e
asw
is the standard exposur e facto r
The stand ard exposur e facto rs appli ed are based on children ’ s exposur es. The foll owing facto rs
are used:

.
Air: 0. 5 m
3
=kg body weight per day (chil dren 1–5 years old)
.
Soil: 0.0002 kg=day if the major part of the TDI is allo cated to inta ke o f the contamina nt
from soil
Soil: 0.0001 kg=day if only a min or part of the TDI is allocated to inta ke of the contaminant
from soil, or if the basis for the soil quality criterion is the 10
À6
lifetime risk for a
carcinogenic substance
.
Drinking water: 0.08 L=day if the major part of the TDI is allocated to intake of the
contaminant from drinking water
Drinking water: 0.03 L=day if only a minor part of the TDI is allocated to intake of the
contaminant from drinking water, or if the basis for the drinking-water quality criterion is
the 10
À6
lifetime risk for a carcinogenic substance
The health-based quality criteria derived as described above are used as the basis for the setting of
quality criteria for chemical substances in soil and drinking water, and of C-values (Contribution
values, the maximum amount of any pollutant a company is allowed to emit in the air) in ambient
ß 2007 by Taylor & Francis Group, LLC.
air. In this step, other than healt h-based view points may be taken into ac count, inclu ding aesth etic
facto rs such as odor (all medi a), disco loration (soil, drink ing water), taste (dri nking water), and
mic robial growth (drinking water).
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ß 2007 by Taylor & Francis Group, LLC.