ARCHIVES HISTORIQUES
DELACOMMISSION
COLLECTION RELIEEDES
DOCUMENTS "COM"
COM(79)296
Vol.1979/0114

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COMMISSION OFTHEEUROPEAN COMMUNITIES
COM(79)296 final
Brussels/June1979
Proposalfora
COUNCILDIRECTIVE
onthelimitvaluesapplicabletodischargesofmercury
intotheaquaticenvironment bythechlor-alkali electro­
lysisindustry
Proposalfora
COUNCILDIRECTIVE
onthequalityobjectivesfortheaquaticenvironment
intowhichmercuryisdischarged bythechlor-alkali
electrolysis industry
A
,•(submittedtotheCouncilbytheCommission)
V:1
v ■.
C0MC79)296final

EXPLANATORY MEMORANDUM
Introduction
Intheirconcerntocombatthepollution offreshandseawater "by
thedischarge ofdangerous substances ,theEuropean Economic
Community anditsMemberStateshavebecomeContracting Partiesto
international conventions whosepurposeistoreduceandeventually
eliminatethistypeofpollution (theConvention forthePrevention
ofMarinePollution fromLand–basedSources andtheConvention on
theProtection oftheRhineagainstChemicalPollution),andare
takingpartinnegotiations forotherconventions withthesame
purpose.Toensuretheharmonized implementation oftheseconven­
tionsandtolaunchageneral andsimultaneous effortbytheMember
States,theCouncilon4May*976approvedDirective 70/464/sSGon
pollution causedbycertaindangerous substances discharged intothe
aquaticenvironment oftheCommunity .ThisDirective stipulates ,
amongotherthings,thatpollution causedbythedischarge of
certainindividual substances whichbelongtoeightfamilies and
groups(knownasListIsubstances )mustbeeradicated inaccordance
withprovisions laiddownbytheDirective .
Inparticular ,everydischarge intothewaterscoveredbythe
Directive whichisliabletocontain oneofthesesubstances requires
priorauthorization bythecompetent authority oftheMemberState
concerned ,whichsetstheemission standards .Thesestandards must
notexceedthelimitvaluesadoptedbytheCounciluponaproposal
fromtheCommission ,withtheexception ofthosecaseswherequality
objectives fixedbytheCouncilarecomplied with.
Forthepreparation ofitsinitialproposals ,theCommission con­
venedameetingofnational expertson14June1976atwhichitwas
decidedthatpriority shouldbegiventothestudyoffivesubstances
theyincludemercuryanditscompounds .Thissubstance waschosenin
viewofitsproperties andthelargequantities ofdischarges con­
tainingit.

Atasecond meeting held on4July 1977 »itwasagreed ,forlimit
values ,that the Corr ,mission would first prepare aproposal concerning
chlor-alkali electrolysis plants ,inview ofthevolume ofdischarges
inthis sector ,andthat itwould continue itswork with aview to
presenting ,assoon aspossible ,proposals for allmercury discharges
covered byDirective 76/464/EEC.Atitsmeetings of5and .6December
1977 120and 21June and13and14November 1978 ,"thegroup of
national experts advised theCommission onthe preparation ofthis
proposal .
Aim oftho first proposal for aDirective
The purpose ofthe Directive iatoeliminate pollution caused by
discharges ofmercury bychlor –alkali electrolysis plant into inland
1surface waters ,territorial waters and internal coastal waters .
Itaccordingly contains provisions forthe application ofDirective
76/464/EBC .
Direct discharges will have tomeet the emission standards complying
with limit values which sireadopted primarily onthebasis of
toxicity ,persistence andbioaccumulation ofmercury andwhich take
into account the best available technical methods .The result will
beasignificant reduction inthese discharges .Additional stipu­
lations aim atbringing about agradual reduction inpollution
caused bydischarges from electrolysis plants which indirectly
introduce mercury into the aquatic environment .
A
Toprotect groundwater against this type ofpollution (aswell as
others ),theCommission haspresented totheCouncil aproposal for
a.Directive ontheprotection ofgroundwater against pollution
caused bycertain dangerous substance (0JIToC37»14February 1978
Ρ·3).

ί
–4-
TheMemberStateswillhavetotalcetheappropriate administrative
measures andcarryoutinspections whichwillenable "theCommission ,
theCouncilandParliament to"beadequately informed oftheapplica­
tionoftheDirective .
Ifittranspires thattheelimination ofpollution ofthistype
demandsfurthermeasures asregardschlor–alkalielectrolysis ,the
Commission willpresentappropriate proposals totheCouncil.
3.Comments onthefirstproposal foraDirective
3.1.Limitvalues
Chlor-alkali electrolysis may"becarriedoutinanisolated plantor
onasitewherethereareseveralindustrial activities .Theopera­
tionofolderplantcausesmuchmorecomplexpollution problems than
thatofnewfacilities .Thediversity ofsituations hasmadeit
necessary todefinedifferent limitvaluesfordifferent typesof
plant.Differentiation asregardsthemaximumallowable concentra­
tionindischarges isarrivedatbymeansofvariables whosevalue
mustbelaiddownforeachplant.Thelimitvaluesproposed for
maximumquantities varywiththedateofentryintoserviceofthe
plantandtheproduction prooess.
3.1.1.Maximumconcentration
Thelimitvalueexpressed asaconcentration relatestothepointof
■discharge intothereceiving environment oftheeffluent discharged
whollyorinpartbyelectrolysis plant.Itisdefinedaccording to
aformulawhosesignificance forstandard casesmaybeinferred from
thefollowing examples .

Inanisolated plant allthemercury –contaminated ,water hasbeen in
contact with the electrolysis installations .These aretheprocess
waters ,used ,forexample ,incondensation operations ,equipment and
site washing water ,andrainwater .Contamination ofthese waters may
beincreased "bythe leaching ofmercury deposited ontheground or
1inthedrainage system after previous electrolysis operations .
When aplant ha3 "been designed touse aminimum quantity ofwater ,
itsconsumption mayapproximate to700l/tchlorine production
capacity formanufacturing andequipment washing operations .
Ifthese waters make upthetotal effluent ofaplant ,theapplica­
tion oftheformula ofthemaximum allowable concentration given in
paragraph 1.1ofAnnex Iwould require that this concentration should
notexceed 700jugmercury /l;thiswould correspond to0.49Smercury /t
chlorine production capacity ,avalue which isseldom complied with in
existing plant .Newplants tobebuilt mayneed less process and
washing water than 700l/tchlorine ,andmercury discharges authorized
inthis instance will therefore beless than 0.49 g/"tchlorine .
Tothese discharges ofmercury ,however ,there must beadded those
inrainwater run–offfrom roofs andtheground which haspicked up
particles ofmercury emanating from chimney stacks orwhich have
permeated theroof orwalls ofthe electrolysis rooms .Inastandard
,unit ofrecent construction ,thetotal amount ofwatercontaminated
bymercury could beestimated at2m^/tchlorine production capacity .
Theconcentration of700yug/linthedischarges thencorresponds to
aquantity of1.4gmercury /tchlorine .
Leaching may even affect other waters .Mospecial provisions are
laid down forthis case intheproposal foraDirective .Leaching of
this kind therefore cannot beadduced asareason for permitting a
higher concentration ofmercury inthedischarges northeemission of
greater quantities ofmercury byplant ofagiven capacity .

-6-
Besidescontaminated water,anelectrolysis plantdischarges other
water,inparticular thatusedforcoolingoperations .Inastandard
plant,therequirements forprocess,washingandcoolingwaterareof
theorderof20m^/tchlorineproductioncapacity.Byapplyingthe
formulagiveninparagraph 1.1ofAnnexI,
$
C=700~ago■70mercury/l«70mgmercury/nr
Thisconcentration corresponds to1.4gmercury/tchlorinepro­
ductioncapacity ,sincethewaterrequirements oftheplantare
20m/tchlorine,andmgmercury/mx20m/tchlorinea1,4g
1mercury/tchlorine •
Waterconsumption figuresoftheorderof20m^/tchlorineare
characteristic ofplantwhichhas"beeninserviceforsomeyears.
Plantofmorerecentconstruction needsmuchmorewater,evenif
thevolumeofcontaminated waterislessthaninolderplants,as
electrolysis iscarriedoutathightemperatures toimprovetheyield.
According toengineers *estimates ,waterrequirements couldbeas
highas100mVtchlorineproductioncapacityintheseplants.
1Conversely ,itispossibletodeducetheconcentration whichwould
correspond ,e.g.,todischarges of0.5gmercury/tchlorineandto
waterrequirements of20m^/tClg*
Thiswouldgive:Cx20m^/tchlorine=0.5gmercury/tchlorine
_0.5gmercury __ /3rtr-C=–^-2–a25mgmercury/m=25}Jg
3 mercury/l

-7-
Anewplant ,within themeaning ofthe Directive ,whose contaminated
effluents were 2m3/tchlorine andwhose cooling water requirements
were98m3/tchlorine should therefore comply withaconcentration
limit value obtained "bythe formula :
2C=700x -xfyro14Pgmercury /l
The discharges from this plant should also becompatible xvith a
limit value expressed interms ofquantity (seeparagraph 3.1.2 ).
Compliance with this value isanadditional constraining factor
affecting themaximum allowable concentration .Ifanewplant whose
total effluent amounts to100m^/tchlorine maynotdischarge more
than 0.5ginercury /tchlorine ,themaximum allowable concentration
inthedischarges would beobtained from thefollowing formula :
Cx100m^/tchlorine =»0.5gmercury /tchlorine
_ 0.5gmercury _ /3 /,C=–IS B5nigmercury /m=5ugmercury /1100m3
Iftheeffluent from electrolysis works (including decommissioned
plant )ismixed with other waste before being discharged ,themaxi­
mumconcentration isproportionately reduced ,since ,intheformula
G='700 Vrefers toallthe effluent discharged ,whether ornot
"itcomes from electrolysis plant .Further ,ifthe effluent which
does not come from this type ofplant contains mercury ,itmust not
betaken into account forascertaining whether the limit value is
1complied with •
1Inpractice ,onecould measure theconcentration C*ofthese dis­
charges before they aremixed andthen make thefollowing calculation :
C'v * , v*:volume ofeffluent atthe point ofmeasurement– where ofC1
Vtvolume ofeffluent atthepoint ofdischarge ,
andoheok whether : mJQQJL

-8-
Thetoxicity ofmercuryfortheaquaticenvironment justifies such
limitvalues.Thelethalconcentration for50$ofasampleofyoung
rainbowtroutisreportedtobe16/og/l.Withadilutionfactorof
8,whichissuggested ascharacteristic ofgoodmixingconditions in
flowingwater,thiswouldcorrespond toaconcentration of128jag
meroury/linthedischarges .
Itmay"befearedthatsub-lethal effects onaquaticorganisms or
theirpredators may"becaused "bymuchweakerconcentrations and,in
accordance withcurrentpractice insuchcases,itwouldappear
desirabletosetalimitconcentration ^indischarges oftheorderof
10yug/l.Ifaccountweretakenofthesynthesisofmethylmercury
intheenvironment ,itsaccumulation infishanditstoxiceffects
onthenervoussystemofconsumers ,theconclusions reachedcould
beevenmorestringent .
3.1.2.Mrocinun cmruntity
InthisproposalforaDirective ,thelimitvaluesareexpressed in
concentration andinquantities pertonneofchlorine production
capacity .Thisvariable waspreferred tothetonneofchlorine
produced becausemercurypollution islargelyindependent ofthe
rateofcapacityutilization .Thetimetable laiddowntakesaccount
oftheoostofthemeasurestobetakentocollect andpurifyall
thecontaminated waters.Theseoperations aremadeparticularly
SeeR.H.W.Schubert :Appraisal oftheecological consequences
(ecotoxicity )ofmercurydischarges fortheaquaticenvironment ,
page41»reportpreparedfortheCommission oftheEuropean
Communities .

difficult "bythepresence on-thegroundandinthedrainage system
ofmercurydischarged previously bytheplantandlikelyto"be
leached.Thismeansthatfairlylongperiodsareneededinwhich
tomeetthecostofcleaningtheeffluent ofthemercuryoriginating
intheseresidual deposits .
Newplantsdonothavetobeconcerned withprevious deposits and
anoptimumwatercollection ajiddrainage systemcanbedesigned
withoutconversion costs;theycantherefore complywiththelimit
valueof0.5gmercury/tchlorinewithoutatransition period.
In1977asurveywasmadeof56plantswhichelectrolysed sodium
chlorideandtoalesserextentpotassiumchloride,usingmercury''.
Oftheseplants,sixproducing about15$ofthechlorine manu­
factured inmercury–cellelectrolysis works,wereusingthe"lost
brine"process.Themercuryconcentrations inthedischarges of
thoseworksaresimilartothosefoundinelectrolysis unitsusing
therecycled brine ,process ,but,sincethevolumesofcontaminated
wateraremanytimesgreaterthanthosedischarged byaplantofthe
samecapacity usingrecycled brine,thequantities ofmercurydis­
chargedbyalost–brineplantarealsomanytimesgreaterthanthose
discharged byarecycled brineplantforthesameproduction capacity ,
Thescaleofthedischarges oftheseplantsmeansthataspecial
effortmustbemadetoachievearelative reduction asalready
required bythecompetent authorities intheMemberStatesconcerned .
*SeeEconomist Intelligence Unit:Theeconomiceffectsofpollution
controlmeasures ondefinedindustrial sectors–mercury-discharging
industries ,p.6;reportpreparedfortheCommission ofthe
European Communities .

-10-
TheCommission proposes that theentry into force oftheDirective
should prompt these establishments tomake aneweffort immediately
andtotake steps foragradual reduction oftheir discharges .
Under these conditions ,theplants inoperation atthedate ofnoti­
fication ofthe Directive will follow aspecial timetable which will
take into account technical possibilities andtheuseful life ofthe
various lost-brine electrolysis plants .Tomeet thetimetable ,some
establishments will have tosupplement orreplaoe their water treat­
ment facilities .This leeway will notbeallowed tonewplants .
3.2 .Authorizations
Compliance with the limit values discussed inpoint 3.1must be
ensured bymeans ofasystem ofprior authorization ofdischarges
delivered bythecompetent authority oftheMember State where the
plant issituated .Each authorization must fixtheemission stan­
dards ,which maynotbeless stringent than the limit values orthe
emission standards already inforce onthedate ofentry into force
ofthe Directive .This istobeinterpreted asfollows .
Ifastandard isexpressed asaconcentration ,itmaybe .applicable
atthe point ofdischarge ,like thecorresponding limit value ,or
upstream ofthat point .Inthelatter case ,itmust bepossible to
establish that the standard ormaximum allowable concentration under
theauthorization isnot less stringent than the limit value .This
implies ,first ,that thestandard applies toallthewaters contami­
nated asaresult ofeleotrolysis operations ,sothat acomparison
canbemade with the limit value .Secondly ,themaximum concentration
ofmercury mustnotexceed thevalue of700jig/lmultiplied bythe
ratio between thevolume ofthecontaminated waters flowing ,through­
outagiven period ,past thepoint orpoints designated inthe
1authorization andupstream ofadischarge point andthetotal volume
ofwater flowing past this point (orthese points )during that period .
1
Asthestandard applies toallthecontaminated waters ,this volume
isequal tothat ofthewaters used forthemanufacture ofelectro­
lysis products which aresubsequently discharged .

11-
Bywayofexception ,if"thestandard appliestowaterswhich ,areto
undergoafurthertreatment ofknownefficiency ,thevaluegiven
abovemayhedivided "bythefraction whichrepresents theresidual
mercurycontentaftertreatment .
Thismayheformulated asfollowst
viforagivenperiod,thevolumedischarged atonepointand
corresponding :
–tothewatersusedinthemanufacture ofelectrolysis pro­
ductsandsubsequently discharged ;
–washingwatersusedintheplant;and
–precipitations formingpartoftheliquideffluent ofthe
plantandcontaminated "bymercurytoadegreesuchthat
theymaybepurifiedifthebestavailable technical
methodsareused;
V:forthesameperiod,alltheliquideffluents whichcome
whollyorinpartfromtheplantandwhicharedischarged at
thepointunderconsideration ;'
V1:forthesaneperiod,alltheliquideffluents oftheplantwhich
flowpastthepointorpointsdesignated intheauthorization
andwhicharriveatthepointofdischarge underconsideration }
ritheeffioienoy ofameroury-removal unitdownstream ofthe
pointorpointsdesignated intheauthorization .Itis
expressed asafigurebetween 0and1;V»:
ΓI

-12-
(l–r):thefractionwhichrepresents theresidualmercurycontent
aftertreatment .
Ifanemissionstandardisexpressed asaconcentration ,itmust
complywiththeforniular
Ca700y"ifthestandardisapplicable atthepointofdischarge
C»700-^7ifthestandardisapplicableupstreamofthepointof
discharge anddownstream ofthemercury–removal
facilities
C»y»ifstandardisapplicable upstreamofthepoint
ofdischarge andofthemercury–removingfacilities .
Theauthorization fixingtheemission standards maybegrantedfora.
periodofuptofiveyears.However ,ifanestablishment installs
anewelectrolysis unittowhichmaybeattributed direotmercury
discharges distinct fromthoseproduced bytheexisting plant,this
newunitmustbetreatedasanewplantandtheauthorization adapted
accordingly .Thisprovision virtually excludes theentryinto
serviceofelectrolysis plantusingthelost-brine process.
3.3.Reduction ofpollution causedbyindirect discharges
Themercuryusedintheelectrolysis operations mayleavetheplant
orremainthereforalongperiod.-Ifitleavestheplant,itmay
beincorporated inaliquid,agasorasolid.Inthefirstcase,
thereisadirectdischarge withinthemeaningoftheDirective and
themercuryemittedmustbecoveredbyemission standards whichmeet
limitvalues.
4
Airborne escapesofmercuryoutsidetheestablishment andmercury
incorporated inelectrolysis products orinsolidwastemaycause
waterpollution ,buttheproposal doesnotlaydownemission stan­
dardsforthesecases.

Yettheselossesaregreaterthanthosethroughdirectdischarges .
Moreover ,mercuryremaining intheplantforalongperiod–often
morethanhalfthetotalconsumption –mayhedischarged tothe
environment ,forexample ,whentheinstallations aredismantled .
Controlofmercurypollution ofwatertherefore demandsaglobal
approach .Firstofall,theconsumption ofmercury must "beanalysed
toobtainaclearerunderstanding ofthecomponents andtoassess
moreaccurately theriskstotheenvironment .TheMemberStateswill
thendrawupplansforgradually reducing emissions which,taking
accountofavailable technical resources ,willleadtominimaldis­
chargesofmercuryintowater.
Monitoring theapplication oftheDirective
Mercury-cell electrolysis plantsareinoperation inalltheMember
StatesexceptIrelandandLuxembourg .
Publicconcernaboutmercurypollution isprompting theauthorities
andtheindustrytomakespecialeffortstoreducemercurydis­
charges.Theseeffortsarecoordinated underinternational conven–•
tionstowhichtheCommunity isaContracting Party.
Forthesereasons',themonitoring oftheapplication oftheDirective
demandsspecialmeasures .
TheMemberStatesaretosupplement themeasures laiddownforthe
checking ofcompliance withdischarge authorizations bystudying
theireffectsinthezonesaffected .Everyfiveyears,theywill
sendtotheCommission areportonallthemeasures takenpursuant
totheDirective andonthereduction ofpollution obtained through
thesemeasures .
Atthemoment,the"unidentif iedlosses"areofthesameorderof
magnitude astheidentified quantities used.

14-
The Con ,mission may askthe Member States for farther information and
will then report totheCouncil andtoParliament ;theCommission will
propose anyfurther measures which itconsiders would help eradicate
mercury pollution .
The Council mayconsider ituseful tosend theCommission ^report to
theinternational "bodies concerned with this type ofpollution .
4. Aim ofthe second proposal for aDirective
TheaimoftheDirective istoeliminate pollution oftheaquatic
environment caused "bymercury discharged from electrolysis plant lay
obtaining compliance with quality objectives .
These objectives arebased onthetoxicity ofmercury ,particularly
forhuman beings ,itspersistence and itsbioaccumulation inthe
aquatic environment .Qnission standards must bederived therefrom .
Compliance with thestandards andobjectives must bechecked in
accordance with theprocedure laid down inthe Directive .
Tosupplement themeans ofcombating thepollution ofthe aquatic
environment bymercury ,provision ismade forthegradual reduction
ofindirect discharges which canmake itdifficult toachieve the
quality objectives .
Finally ,theproposal lays down that theCommission ,after receiving
information from theMember States ,reports totheCouncil andto
Parliament onthe application ofthe Directive andpresents proposals
asprovided forinArticle 6(3)ofDirective 76/464/EEC.

-15-
5. Cormorrts onthe second proposal foraDirective
5.1•Quality objective ?;
5.1.1 .'ritor
Infresh water ,the objective iatheguide value laid down in
Directive 75/440/EECconcerning thequality required ofsurface water
intended fortheabstraction ofdrinking water :0.5ug/l*
Theguide value isselected inaccordance with Article 4ofthe
Directive ,which requires substantial improvements tothequality
ofwater botween 1975 and .1985 *Thequality objective must be
complied with by1July 1983 *
Inestuaries andcoastal waters ,the quality objective isset at
0.05 ug/l.Theselection of/thisvalue isaguarantee against
increased contamination ofthewaters inquestion .Furthermore ,it
incorporates adequate safety coefficients forthemarine species
1about which theCommission possess scientific data .
5.1.2 .Fish
Theprotection offish species would beguaranteed bythequality
objectives adopted forwater .However ,those whoconsume themost
fish need specific protection .
1These data aregiven inthereport "Appraisal oftheecological
consequences (ecotoxicity )ofmercury discharges fortheaquatic
environment ",prepared byProf. R.H.W. Schubert fortheCommission
oftheEuropean Communities .

-16-
Thequalityobjective adoptedis0.3mgmercury/kgwetfishflesh.
Itappliestoarepresentative sampleofthefishconsumption of
personsexposedtosubstantial risk.Thefirstsymptoms ofmercury
poisoning maybesaidtooccurasfollows:
WHOconsiders thatinthemostsensitive subjectstheeffectsof
methylmercurycanbedetected asfromabloodconcentration of
20to50^g/100ml.Byregression analysisitcanbefoundthat
thisconcentration corresponds atleasttoadallyintakeofmethyl
mercuryof3.5Jig/kgbodyweightforapersonof70kg.
Thisfindingisconfirmed bydirectestimates oftheintakeofmethyl
mercurylikelytocausedisorders inhumanbeings;itisthoughtto
beequalorgreaterthan3jag/d/kg^,whichcorresponds to210jJg/d.
Theconsumption ofotherfoodstuffs besidesfishdoesnotleadtoan
ingestionofmercurygreaterthan5ps/^m
Drinking waterconsumed cannotcontainamercurycontentofover
2pg/d,iftheCommunityDirectives onthissubjectareapplied.
Theambientaircarriesnomorethan50"Smercury/m^,equivalent '
toanexposureof1^ig/d^.If,tosimplifythecalculations we
assumethatexposures ofthesethreetypesareentirely dueto
methylmercurywhichtheorganismassimilates toarateof100$
Λ
WHO.Environmental HealthCriteria 1sMercury ;Geneva,197°.
2
WHO,op.cit.,pp80and118.
^SeeDepartment oftheEnvironment ,Environmental MercuryandMan,
Pollution PaperHo.10,HMS0,London,1976.
^SeeWHO,op.cit.,pp64and65.

-17-
aconsumersensitivetomethylmercurycouldingest200}ig/dofthis
substance "beforerunningtheriskofsuffering toxiceffects ,provided
«1thatheisnotexposedtomercury "byreasonofhisoccupation -.
Ifthefishconsumed contains 300kgmercury ,aconsumer could
ingesttwo-thirds of1kg/d"beforerunningariskofnervousdis-
2orders,theprobability ofwhichislessthan5/i>•
Thehighestdailyconsumption ratesrecordeddonotexceed$00g^.
Thequalityobjective adoptedwouldtherefore beadequatetoprotect
consumersagainsttherisks,ascurrentlyidentified^.
However,theCommission couldohangethisopinionifnewtoxicological
effectsduetotheingestion ofmercury ,orbiochemical orphysio­
logical damageforintakesbelowthetoxicity threshold were
discovered ^.
1Themainconsumers ofmercuryarefishermen whoarenotexposed
torisksofpoisoning byvirtueoftheiroccupation ,asdistinct
fromthoseoonnected withtheirconsumption pattern.
2SeeWHO,op.cit.,p.66.
?SeeWHO,op.cit.,p.118.
^InMinamataBaythemercurycontentofthefishfleshhasreached
50.000yug/kg,seeDOSop.cit.,p.7»
^WHOhasdrawnparticularattentiontothispoint;seeWHOop.
oit.,p.26.

-18-
5.1 .3.Sediments and r.'iolluncn
Themercury content ofsediments isimportant fortheprotection of
theenvironment ,particularly "because they arethought to "bethesite
where bacteria synthesize methyl mercury passing through thefood
1chain •Itisnot atpresent possible topropose amaximum mercury
content forsediments ,butinprinciple itcanbeascertained whether
thecontent isincreasing ornot .
Itmaybedifficult toobtain this information ,asthemovements of
sediments over aperiod oftime arelikely toprevent theresults
obtained boing comparable .Inthis case itwould bepreferable to
observe sedentary organisms which accumulate mercury ,andthis is
whytheproposal foraDirective includes this possibility .
5.2 . Coi..nlip.nce with the objectives ■
Theproposal foraDirective provides that thequality objectives are
tobeattained bymeans ofcompliance with emission standards for
direct discharges andtheimplementation ofprogrammes toreduce
pollution caused byindirect discharges .
This dual approach isnecessary ,asindirect discharges are
responsible foralarge proportion ofmercury pollution .Toignore
them would make itvery difficult toensure compliance with the
objectives .
SeeWHO ,op.cit..pp.5® "to5°*

-19-
5.3.Honitonrvr procédure nndrcnort
Foreachqualityobjective ,theproposalstipulates :
(i)thepreliminary researchtohecarriedout:
(ii)samplingfrequency ;
(iii)thereference methodofanalysis ;
(iv)themethodofexpressing andinterpreting theresults.
Theinformation whichtheMemberStatesapplyingtheDirective will
supplyeveryfiveyearsontheimplementation ofthemonitoring
procedure willenabletheCommission topreparethereporttothe
CouncilandtheproposalsreferredtoinArticle6(3)ofDirective
70/464/EBC.
Theproposal provides thattheCommission willalsoreportto
Parliament ontheapplication oftheDirective .Theimportance
whichpublicopinionattachestomercurypollution makesthisreport
particularly advisable .
6.Consultation ofParliament andoftheEconomic andSocialCommittee
Astheseproposals forDirectives arebasedonArticle 6of
Directive 76/464/ESC1consultation ofParliament andoftheEconomic
andSocialCommittee isnotrequired.However ,theCommission con­
siders,inviewofthepolitioal importance oftheproposals ,that
theyshouldbesubmitted toboththeseInstitutions .

-20-
Proposal for aCouncil Directive on "the
limit values applicable todischarges of
mercury into theaquatic environment "by
thechlor-alkali electrolysis industry
THE COUNCIL OPTHEEUROPEAN COMMUNITIES ,
Having regard toCouncil Directive 76/464/EECof4May1976 onpollu­
tion caused bycertain dangerous substances discharged into theaquatic
1environment oftheCommunity ,and inparticular Article 6thereof ,
2Having regard totheproposal from theCommission t
Having regard totheopinion oftheEuropean Parliament "^,
4Having regard totheopinion oftheEconomic andSocial Committee ,
Whereas ,inorder toprotect theaquatic environment oftheCommunity
against pollution "bycertain dangerous substances ,;Art icle3ofDirec­
tive 76/464/EECprovides for asystem ofprior authorization laying
down emission standards fordischarges ofthesubstances falling with­
inList Icontained intheAnnex thereto ,andArticle 6thereof pro­
vides that limit values shall belaid down for such emission standards ;
OJNoL129of18May 1976 ,p.23.
2
3
4

-21-
Whereas mercury anditscompounds areincluded m"theList;
VJhereasthatDirective alsoprovides fortheestablishment ofquality -
objectives ,andwhereasthesehavebeenlaiddowninCouncil
Directive ;
Whereas ,sincethepollution causedbydischarges ofmercuryintowater
arisesprincipally fromtheelectrolysis ofalkalichlorides ,inthe
firstinstance Limitvaluesshouldbeestablished forthisindustry and
itsdischarges madesubjecttopriorauthorization ;
Whereasprovision shouldbemadefortheMemberStatestofixemission
standards andtime–limitswhicharenolessstringent thanthelimits
laiddownbytheCouncil ;
WhereastheMemberStatesshouldtaketherequisite measures toensure
thatdischarges andtheireffectsaremonitored ;
Whereasitisimportant thattheMemberStatesshouldtakemeasures to
reducepollution causedbymercurydischarged indirectly intothe
aquaticenvironment ;
Whereas ,sincegroundwater istobethesubjectofaspecific Directive ,
itisexcluded fromthescopeofthisDirective ;
Whereasitisimportant thattheCouncil andtheEuropean Parliament
bekeptregularly informed astotheoperation oftheDirective,
HASADOPTED THISDIRECTIVE ,
1

-22-
Article 1
1.Thepurposeof-thisDirective istolaydown/forthechlor-alkali elec­
trolysis industrythelimitvalueswhichemissionstandards mustnotex­
ceedandthetime-limits forimplementation inrespectofdischarges of
mercuryanamercury compounds intotheaquaticenvironment .~
2.ThisDirective appliestothewatersreferred toinArticle 1of
Directive 76/464/EEC,withtheexception ofgroundwater .
Article 2
Forthepurposes ofthisDirective :
(a)"limitvalue"means:
-themaximumallowable concentration ofmercury anditscompounds
indirectdischarges ;
-themaximumquantity ofthesesubstances whosedischarge has
"beenauthorized ,inrelationtotheproduction capacityofthe
establishments inquestion ;
(b)"discharge "meanstheintroduction "byanindustrial establishment
ofmercuryoritscompounds intothewatersreferred toin
Article1(2);
(c)"directdischarge "meansanydischarge whichhasnotbeforehand
been:
-bornethroughtheairoutsidetheindustrial establishment ,or
incorporated intotheproducts orwastes;
(d)"indirectdischarge "meansanydisoharge whichisnotadirect
discharge ;

-23-
"industrial establishment "means any plant where alkali chlorides
areorhave been electrolysed andwhich is"inaposition tomakedirect
discharges ofmercury which ,maybedirectly attributed toit;
"existing establishment "means anindustrial establishment in
operation onthe date ofnotification ofthis Directive ;
"newestablishment "means anindustrial establishment brought
into operation after the date ofnotification ofthis Directive .
Article 3
The emission standards ,thetime–limits forcompliance andthe sampling
frequencies laid down inthe authorization referred toinArticle 3of
Directive 76/464/EECshall comply with thelimits given inAnnex Ito
this Directive .
Themethods ofanalysis laid down intheauthorization shall comply
with thereference method ofanalysis given inAnnex IItothis
Directive .Where theuse ofother methods ofanalysis isauthorized ,
such methods shall comply with thedetection limit ,precision and
accuracy laid down inAnnex II.
Noauthorization maybegranted foraperiod ofmore than five years .
Article 4
The Member States shall draw upprogrammes forthegradual reduction
andeventual elimination ofpollution caused byindirect discharges
into thewaters referred toinArticle 1(2).These programmes shall
provide forananalysis oftheconsumption ofmercury byindustrial
establishments andshall laydown intermediate objectives tobe
reached seven years after notification ofthis Directive .(•)
(D
(g)

Article 5
TheMember States shall keep the entire zone affected bythedischarges
from industrial establishments under surveillance and shall monitor
the effects ofthese discharges .Inthe event oftransfrontier pol­
lution affecting more than oneMember State ,theStates concerned
shall act inconcert with aview toadopting appropriate control
measures and shall forthwith inform the Commission thereof .
Article 6
Every five years following notification ofthis Directive ,theMember
States shall draw upandsend totheCommission areport onthe
reduction ofpollution caused bydischarges ofmercury into theaquatic
environment bythe chlor –alkali electrolysis industry .
TheMember States shall ,inaccordance with Article 13ofDirective
76/464/1100 ,supply theCommission ,atitsrequest ,with anynecessary
additional information specifically concerning :
–theauthorizations granted inaccordance with Article 3andin
particular theemission standards ,themonitoring procedures
introduced ,thesampling frequencies andthemethods ofsample
analysis ;
–theprogrammes forthegradual reduction ofthepollution in
question ,drawn uppursuant toArticle 4»
–theresults ofthesurveillance andmonitoring carried outin
accordance with Article 5*
TheCommission ,onthebasis oftheinformation ithasreceived pursuant
tothis .Article ,shall report every five years totheCouncil andto
theEuropean Parliament onthe ._operation ofthis Directive and ,if
necessary ,shall place appropriate additional proposals before the
Council .

25-
Article 7
1.TheMem"berStatesshall,wzthmtwoyearsofthedateofnotification
ofthisDirective ,"bringintoforcethemeasures necessary tocomply
therewith andshallforthwith informtheCommission thereof.
2.TheMemberStatesshallcommunicate totheCommission thetextsofthe
provisions ofnational lawwhichtheyadoptinthesectorcovered "by
thisDirective .
Article 8
ThisDirective isaddressed totheMemberStates.
Doneat
FortheCouncil ,
ThePresident

ATOTEXI
Limitvaluesandtime–limits
Thelimitvaluesandtime–limitswithinthemeaningofArticle1(1)are
asfollows :
Maximum concentrations
Ateachpointofdischarge theaveragemonthlyconcentration ofthe
mercuryemittedasaresultofchlor–alkalielectrolysis operations may
not"begreaterthanthatgivenbytheformulas
c-700j
whereC=maximumallowableconcentration inpgmercury/l
v«■volumedischarged ataspecific pointandcorresponding ,
forthemonthinquestion ,to:
(a)thewaterusedinthemanufacture oftheproductsof
electrolysis andsubsequently discharged ,
(b)thewashingwaterusedintheplant,and
(c)theprecipitations whichformpartoftheeffluent
fromtheplantandwhicharecontaminated bymercury
toadegreesuchthattheycanbepurifiedifthe
bestavailable technical meansareused*
V»alltheeffluentarising,inwholeorinpart,fromplant
overthesameperiodandwhichisdischarged atthepoint
inquestion .
Inordertocheckcompliance withthelimitvalues,measurements must
betakenatleastonceadayfromrepresentative discharge samples.where C■
V«■

27-
The sampling method must allow forinstantaneous values forconcentra­
tion andflow insuch away astoensure that the samples are
representative ^.
The average monthly concentration must hecalculated onthe basis of
the arithmetic mean ofthedaily average concentrations *
1.2 .Theprovisions ofparagraph 1.1apply toestablishments existing at
1July 1983 .They apply tonewestablishments :
–twoyears after thedate ofnotification oftheDirective ;
–assoon astheestablishment isbrought into service ifthis
occurs after that date .
2. Maximum quantities
2.1 .Existing recycled –brine plants
ouch plants maynotdischarge ,onanaverage monthly basis ,directly
into thewaters referred toinArticle 1(2)more than :
(a)1.5gmercury /tchlorine at1July 1983
(b)1gmercury /tchlorine at1July 1986
(c)0.5gmercury /tchlorine at1July 1989 .
Inthis andsubsequent paragraphs theexpression "tchlorine "refers
totheproduction capacity .
1Itisaccepted that the analysis every 24hours ofasample
constituted inproportion tothe flow meets this requirement .
The concentration measured mayberegarded asadaily average .
Hourly analysis ofsamples coupled with aflow measurement isalso
permitted .Daily concentrations must then becalculated asthe
average oftheconcentrations measured ,weighted bytheflow
readings .ouch
into
(a)
(b)
(c)

-28-
2.2.Exintirvr lost-brine T)lant3
Suchplantsmaynotdischarge ,onanaveragemonthly "basis,directly
intothewatersreferredtoinArticle 1(2)morethan:
(a)8gmercury/tchlorineat1July1983;
(b)5gmercury/tchlorineat1July1986;
(c)2.5gmercury/tchlorineat1July1989.
2.3.-Tcvfestablishments
Suchestablishments maynotdischarge ,onanaveragemonthlybasis,
morethanO.5gmercury/tchlorinedirectlyintothe.watersreferred
.toinArticle1(2):
–twoyearsafterthedateofnotification oftheDirective ,or
-assoonastheestablishment isbroughtintoservice ,ifthis
occursafterthatdate.

ÂOTJEX II
ReFerence method ofanalvsis
Forthepurposes ofArticle 3,"thereference method ofanalysis is
flameless atomic absorption at0.2537 um»after pre–oxidation ofthe
unfiltered sample andreduction ofthemercury ions Hg(II)by
stannous chloride (SnCl^)andentrainiaent ofthemercury vapours .
–Detection limit*:0.0001 rag/lHg
–Précision * ï+15$
–Accuracy * I4-30$
*cf.thedefinitions given intheproposal foraCouncil
Directive onthemethods ofmeasurement andfrequencies of
sampling andanalysis oftheparameters ofthequality required
ofsurface water intended fortheextraction ofdrinking water in
theMember States (0JNoC208 ,of1September 1978 )*

-30-
ProposalforaCouncilDirective onthequality
objectives fortheaquaticenvironment intowhich
mercuryisdischarged laythechlor–alkali
electrolysis industry
THECOUNCIL OPTHEEUROPEAN COMMUNITIES ,
HavingregardtoCouncilDirective 76/464/EECof4May1976onpollution
causedbycertain -dangerous substances discharged intotheaquatic en^
•1*vironment oftheCommunity ,andinparticular Article 6thereof/
2Havingregardtotheproposal fromtheCommission f
HavingregardtotheopinionoftheEuropeanParliament^,
HavingregardtotheopinionoftheEconomicandSocialCommittee^,
Whereas,inorder ,toprotecttheaquaticenvironment oftheCommunity against
pollution bycertaindangerous substances.Article 3ofCouncilDirective
76/464/EECprovidesforasystemofpriorauthorization layingdown
emission standards fordischarges ofthesubstances fallingwithinList
Icontained intheAnnexthereto,andArticle 6thereofprovides that
limitvaluesshallbelaiddownforsuchemission standards andalso
qualityobjectives fortheaquaticenvironment affected bythese
substances ; ,
OJNoL129of18May1976,p.23
2
.3
4

Whereasmercury anditscompounds areincludedintheList:
1,WhereasCouncilDirective •••laysdown limitvaluesfordis­
chargesofmercuryintotheaquaticenvironment ;
Whereas,althoughtheMemberStatesarerequiredtoapplythelimit
values,theymayincertaincasesemployasystemofquality
objectives ;
Whereasamonitoring procedure shouldbeinstituted toenablethe
MemberStatestodemonstrate thatthequalityobjectives are
complied with;
Whereas,sincethepollution causedbydischarges ofmercuryinto
waterarisesprincipally fromtheelectrolysis ofalkalichlorides ,
qualityobjectives should,inthefirstinstance ,belaiddownfor
theaquaticenvironment intowhichmercuryisdischarged bythis
industry andthesedischarges shouldrequirepriorauthorization .
Whereas,inordertoattainthequalityobjectives ,MemberStates
shouldlaydovmemission standards intheauthorizations grantedand
whereastheMemberStatesshouldtakestepstoreducepollution caused
bymercurydischarged indirectly intotheaquaticenvironment ;
Whereasitisimportant thatreportsbeprepared oncaseswherethe
systemofqualityobjectives hasbeenapplied ;
Whereas,sincegroundwater istobethesubjectofaspecific Directive ,
itisexcluded fromthescopeofthisDirective ,
HASADOPTED THISDIRECTIVE :
1

Article 1
Thepurpose ofthis Directive istolaydown quality objectives for
theaquatic environment into which mercury isdischarged laythechlor –
alkali electrolysis industry andtoinstitute amonitoring procedure .
This Directive applies tothewaters referred toinArticle 1of
Directive 76/464/EBC >with theexception ofgroundwater .
Article 2
Forthepurposes ofthis Directive :
(a)"quality objective "means themaximum allowable concentration
ofmercury oritscompounds inthe aquatic environment concerned ;
(b)"discharge "means theintroduction byanindustrial establish­
ment ofmercury oritscompounds into thewaters referred toin
Article 1(2);
(c)"direct discharge "means anydischarge which hasnotbeforehand
been :
borne through the airoutside the industrial establishment ;
or
incorporated into the products orwaste ;
(d)"indirect discharge "means anydischarge which isnotadirect
discharge ;
(e)"industrial establishment "means anyplant where alkali
chlorides areorhave been electrolysed andwhich isinaposition
tomake direct discharges ofmercury which maybedirectly
attributed toit.

-33-
Article 3
TheMember States shall draw upprogrammes forthegradual reduction
andeventual elimination ofpollution caused Toyindirect discharges
into thewaters referred toinArticle 1(2).
These programmes shall provide forananalysis oftheconsumption of
mercury "byindustrial establishments andshall laydown intermediate
objectives tobereached seven years after notification ofthis
Directive .
3
Article 4
Where thearea liable tobeaffected bythedischarges isatrans -
frontier area ,theMember States concerned shall consult oneanother
onthe implications arising from the application ofthis Directive
and shall forthwith inform the Commission thereof .
Article 5
1.Every five years following notification ofthis Directive ,the
Member States shall draw upand send tothe Commission areport on
thereduction ofpollution caused bydischarges ofmercury into the
aquatic environment bythe chlor –alkali electrolysis industry .
2.TheMember States shall ,inaccordance with Article 13ofDirective
76/464/E0C ,supply theCommission ,atitsrequest ,with anynecessary
additional information specifically concerning :
-the authorizations granted andinparticular the emission
standards ,
-theimplementation ofthemonitoring procedures ,
-theprogrammes forthegradual reduction ofthepollution in
question ,drawn uppursuant toArticle 3,

–theapplication oftheDirective totransfrontier areas,in
accordance withArticle 4*
TheCommission ,onthe "basisoftheinformation ithasreceived
pursuanttothisArticle,shallreporteveryfiveyearstothe
CouncilandtheEuropean Parliament ontheoperation ofthis
Directive andshallplaceappropriate proposals "beforetheCouncil,
onwhichthelattershallactpursuanttoArticle6(3)of
Directive 76/464/EEC•
Article 6
TheMemberStatesshall,withintwoyearsofthedateofnotification
ofthisDirective ,bringintoforcethemeasures necessary tocomply
therewith ' •andshallforthwith informtheCommission thereof.
J
TheMemberStatesshallcommunicate totheCommission thetextsof
theprovisions ofnational lawwhichtheyadoptinthesectorcovered
bythisDirective .
Article 7
ThisDirective isaddressed totheMemberStates.
Doneat
FortheCouncil,
ThePresident

ΛΙΓΝΕΧI
Qualitv objectives
*Thefollowing stipulations applyintheareasaffected "bydischarges
fromindustrial establishments :
1.Theconcentration ofmercuryinwatersmustnot "bemorethan
0.5jug/lwithinthefreshwater limit.Itmustnothemore
than0.05>Jg/lbeyondthislimit.
2.Themercurycontentinthefleshoffishlivingbeyondthe
freshwater limitmustnotexceed0.3mg/kgwetweight.
3.Themercurycontentinsediments orinacharacteristic mollusc
mustnotincrease withthepassageoftime.
4.Thesequalityobjectives mustbeattained by1July1983#

-36-
AN1J3XII
Monitorirvt nrocedure
ICompliance withthequalityobjectives laiddowninpoint1of
AnnexImust "bemonitored asfollows :
1.Foreachgeographical areaaffected bythedischarges threezones
mustbedemarcated :
ATheimmediate mixingzone:zoneintheimmediate vicinity of
thedischarge pointwherethedegreeofdilutionisveryslight;
BDispersion zone:zonemoreremotefromthedischarge point
characterized byahigherdegreeofdiffusion andgreater
discharge dilution ;
GZoneunaffected bythedischarges :zonewheretheeffectsofthe
discharges arenotdetectable .
2.Samples mustbetakenoveranetworkofpointslocatedinsuchaway
thatthesamplestakenarestatistically representative ofthe
qualityofthewatersthroughout zoneB.
Theconcentration ofmercury mustbedetermined ateachsampling point
andthedilutionfactorforthemercurydischarged bytheindustrial
establishment ^)concerned mustbeestimated bydividingthecon­
centration inthedischarges bythehighestconcentration measured
inthezone.
3.Thedischarge standard mustbefixedorreviewedinthelightofthe
qualityobjective andoftheconcentrations measured ,bearinginmind
thepossibilities ofadditional mercurydischarges inzoneBduring
theperiodcoveredbytheauthorization .

Inordertocheckcompliance with"thestandard ,measurements must "be
takenatleastonceadayfromrepresentative discharge samples.
Thesampling methodmustallowforinstantaneous valuesforcon­
centration andflowinsuchawayastoensurethatthesamplesare
representative .Thereference methodisthatdefinedinAnnexII
totheproposal foraCouncilDirective onthelimitvaluesapplicable
todischarges ofmercuryintotheaquaticenvironment "bythechlor–
alkalielectrolysis industry.
Compliance withthequalityobjective mustheestimated daily "by
dividing theconcentration measured inthedischarges "bythedilution
factor.
.Themercuryconcentration inthereceiving watersnrust "bemeasured
directly everysixmonthsandthedilution factorre–estimated on
thatoccassion .
Ifthevaluemeasuredismorethan0.4pig/lwithinthefreshwater
limitand0.04>ig/l"beyondthislimit,themeasurements must"betaken
morefrequently .
Measurement ofthemercuryconcentration inthereceiving watersmust
becarriedoutfromanunfiltered sample.Thereference methodof
analysisisthatreferredtoinpoint4»andiscarriedoutafter
themercuryhasbeenconcentrated incarbontetrachloride inthe
formofdithizonate andextracted .
Detectionlimit:0.004pgmercury/l
Precision s+15f°
Accuracy :+30$

-38-ι
IICompliance withthequalityobjective laiddowninpoint2of
AnnexImust "bemonitored asfollows:
1.Ineachoftheareasinthevicinity ofanindustrial establishment
whichmakesdischarges "beyondthefreshwater limit,theconsumption
patternofthemainfish–eatersisto"bestudiedinordertodraw
upatypicaldiet.
2.Asampleoffishmuscletissuereflecting thepatternofthe
typicaldietisto"betakeneverysixmonthsfromeachzoneaul
thissampleistobeanalysed .Ifthevaluemeasured exceeds
0.25/Jg/kg,themeasurements mustbetakenmorefrequently .
3.Thereference methodofanalysisisthatreferredtoinpoint 1.4
andiscarriedoutafterthiesampleha3beentakenupinsolution
withnitricacid.
Detectionlimit:10jagmercury/kg
Precision :+5$
Accuracy :+15$
IIICompliance withthequalityobjective laiddowninpoint3of
AnnexImustbemonitored asfollows :
1.Ineachoftheareasinthevicinity ofanindustrial establish­
ment,thecompetent national authority decideswhetheritis
preferable toselectsediment oraspecific molluscasthe
indicator ofchangesinthemercurycontentwiththepassageof
timeintheareaconcerned .
2.Samplesmustbetakeneverytwelvemonthsofthetargetselected
suchthatthesamplesarestatistically representative ofthe
areainquestion.

-39-a
3.Thereference methodofanalysisis"thatreferred ,toinpoint
1.4andiscarried outafter:
–digestion withnitricacidinthecaseofsediment ;
theresultsmust "beexpressedinmgmercury/kgdrymatter,and
–separation ofthesolidandliquidsubstances anddigestion
withnitricacidinthecaseofmolluscs .
Theanalysis mustbecarriedoutonthesolidsubstances .
Detectionlimiti10pgmercury/kg
Precision :+5%
Accuracy :+15%
4.Inordertoensurethatthequalityobjective ismaintained ,the
resultsofthemeasurements carriedoutoveragivenperiodmust
not,onaverage ,besignificantly higherthanthoseobtained the
previous year.
Thesignificance threshold is9