Royal Society of Chemistry Environmental Chemistry Group

(www.rsc.org/ecg)

January 2015

ECG Bulletin

We are celebrating! Twenty years ago, the first issue of this publication, then called the ECG Newsletter, was published. For this anniversary, we are taking an opportunity to look back at some past issues of the ECG Bulletin and to review some of the topics that have engaged those who teach and research into environmen-tal chemistry in the UK (pages 4-12).

Threats to avian predators. Avian predators such as vultures are under

threat in Africa and Europe, both from deliberate poisoning and from veterinary agents in carcasses that they feed on. Read more on page 17.

Environmental Briefs. We continue our series of concise environmental chemistry primers with Briefs on how to calculate atmospheric lifetimes of trace gases (page 21) and on meas-uring NO2 concentrations (page 23).

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 2

ECG Bulletin

ISSN 1758-6224 (Print) 2040-1469 (Online)

Published by the Royal Society of Chemistry’s RSC Environmental Chemistry Group ECG , BurlingtonHouse,Piccadilly,LondonW1J0BA,UK

Executiveeditor

JuliaFahrenkamp‐Uppenbrink

ecgbulletin@hotmail.co.uk

Productioneditors

RogerReeve,UniversityofSunderland

roger.reeve@sunderland.ac.uk

RowenaFletcher‐Wood,BirminghamUniversity

rls155@bham.ac.uk

EditorialBoard

StephenBall,LeicesterUniversityJoBarnes,UniversityoftheWestofEngland,BristolBillBloss,UniversityofBirminghamZoëFleming,UniversityofLeicesterMartinKing,RoyalHolloway,UniversityofLondonJamesLymer,WardellArmstrongLLP,SheffieldRupertPurchase,HaywardsHeathIanForber,ALcontrolLaboratoriesCeciliaFenech,CranfieldUniversity

Environmental Chemistry Group www.rsc.org/ecg

Chair:JamesLymer,WardellArmstrongLLP,Sheffieldjlymer@wardell‐armstrong.com

Vice‐Cair:BillBloss,UniversityofBirminghamw.j.bloss@bham.ac.uk

HonorarySecretary:ZoëFleming,UniversityofLeicesterzf5@leicester.ac.uk

HonoraryTreasurer:JoBarnes,UniversityoftheWestofEngland,Bristol annaoj_senrab@hotmail.com

ThisandpreviousissuesoftheECGBulletinareavailablewithoutchargeonlineatwww.rsc.org/ecg.ForECGmembershipdetails,visitwww.rsc.org/Membership

ECGBulletin©TheRoyalSocietyofChemistry–EnvironmentalChemistryGroup2015

RegisteredCharityNumber207890

Contents Chairman’sreportfor2014 3

Anniversaryarticle:ECGBulletinandECGNewsletter,January1995–January

2015,byRupertPurchase 4

AnniversaryArticle:Environmentalchemistry:atwentyyearperspective,byLeoSalter,James

Lymer,JoBarnes,CeciliaFenechandIanForber 7

AnniversaryArticle:Environmentalchemistrydegrees–thenandnow,by

ZoëFleming,HattieChisnallandJashviniJothieswaran 11

ForthcomingMeeting:Newdevelopmentsintheanalysisofcomplexenvironmentalmatrices 13

Update:WMOGreenhouseGasBulletinNo.10 14

Meetingreport:Chemicalatmosphere–snow–seaiceinteractions:takingthenextbigstepin

field,laboratoryandmodelling,byMartinKing 15

ECGInterview:IanForber 16

Article:VeterinaryagentsandpoisonsthreatenavianscavengersinAfricaandEurope,byNgaio

RichardsandDarcieOgada 17

ForthcomingMeeting:Emergingcontaminantsinwaterandsoils,practicalconsiderations:

sampling,analysisandconsequences 20

ECGEnvironmentalBriefNo7:Atmosphericlifetimesoftracegases,byStephenBall 21

ECGEnvironmentalBriefNo8:HowpassivediffusiontubesmeasureNO2concentrations,byMathewHeal 23

Oily water on a London Street

The ECG Bulletin is printed on paper made from wood pulp sourced from sustainable forests, and is suitable for archival storage. This issue of the ECG Bulletin was printed by Prizmatic Print Solutions, www.prizmatic.co.uk; 01444 239000.

During 2014, the Environmental Chemistry Groupcommittee organised a number of successful meetings,events and activities across a range of topics andformats,insomecasesjointlywithotherinterestgroups,andorganisations.In February, the ECG and the RSC Toxicology Groupjointly arranged an event on Organic Chemistry andToxicityofContaminants in theGround.At this one‐daymeeting, about 54 delegates heard presentations fromseven speakers on topics including Emerging organicgroundwater contaminants and their transformationproducts by Marianne Stuart BGS , Side Effects ofMedication in the Soil Environment by Prof. AlistairBoxall UniversityofYork andTheEnvironmentalFateSimulator: a tool for predicting the degradationpathwaysoforganic chemicals ingroundwateraquifersbyDrEricJ.Weber USEPA .AmeetingreportappearedintheJuly2014editionoftheECGBulletin.This meeting was followed by the 2014 DistinguishedGuest Lecture and Symposium on 12th March, on thetopic of Plastic debris in the ocean – a globalenvironmental problem. The speakers were Prof.NormanBillingham UniversityofSussex,Polymersandtheir environmental degradation , Dr Edwin FoekemaIMARES, Aspects that determine the actual risk ofplastic associated POPs for marine organisms , and DrHeather Leslie VU University, Macroplastics andMicroplastics–whatistheirenvironmentimpact? .TheDistinguished Guest Lecture was delivered by Prof.RichardThompsonofPlymouthUniversity,whospoketothesymposiumtitle.DetailedreportscanbefoundintheJuly2014editionoftheECGBulletin.About48delegatesattendedthemeeting.On 10th December, the ECG and theMolecular PhysicsGroup of the Institute of Physics IOP co‐organised ameetingonSoftionisationmassspectrometrictechniquesand the environmental sciences at the University ofBirmingham.Thishalf‐daymeetingfollowedonfromthesuccessfulmeetingson thissubjectarea inrecentyearsandwasattendedby36delegates,withtalksfromProf.Thomas Karl University of Innsbruck, Austria , DrRachaelBeale PlymouthMarine Laboratory ,DrGavinPhillips UniversityofChester ;andDrMarkusKalbererUniversityofCambridge .Alongside our programme of events, ECG Committeemembers Julia Fahrenkamp‐Uppenbrink, Roger Reeve,

Rowena Fletcher‐Wood and Cecilia Fenech havecontinued to produce the biannual ECG Bulletin. Arevised format of the ECG Bulletin was introduced forthisyear’sJulyedition.DrMartinKing RoyalHolloway has been active in the further development of the ECGEnvironmentalBriefs,aseriesofshortdocumentsgivingabriefbutpreciseintroductiontotopicsofrelevancetoenvironmentalchemistry.ECGEnvironmentalBriefsonAtmosphericchemistryatnight,Atmosphericparticulatematter,AsbestosinsoilsandPourbaix pE‐pH diagramsfor the aquatic environment were published in theJanuary and July 2014 editions, respectively. FurtherBriefsappearonpages21and23ofthisissue.TheBriefsalso have a dedicated web page on the ECG Groupwebsite www.rsc.org/Membership/Networking/InterestGroups/Environmental/index.asp .Forthcomingevents in2015 includeNewdevelopmentsintheanalysisofcomplexenvironmentalmatrices,aone‐day meeting to be held at Burlington House on 6thFebruary 2015 see page 13 , and Emergingcontaminants in waters and soils, practicalconsiderations: sampling, analysis and consequences, aone‐daymeeting to be held at The Source, Shef ield on4thMarch2015 see page 20 . The2015ECGDGL andSymposiumwillbeheldon24thJune2015,atBurlingtonHouse. The topic for this event is ‘Nanomaterials:environmental remediants or toxicants?’, and the 2015Distinguished Guest Lecturer will be Professor ÉvaValsami‐Jones ProfessorofEnvironmentalNanoscienceat Birmingham University . Booking and programmeinformationwillbesentoutsoontoallECGmembers.The committee is always keen to hear from members,including feedback on events, suggestions for futureactivities,andotherideas,andwelookforwardtoseeingyouin2015.The Environmental Chemistry Group held its 40thAnnual General Meeting in 2013, while 2015 sees thetwentieth anniversary since the irst editionof theECGBulletin formerly the ECGNewsletter , an anniversarythatwearecelebratingwithasetofarticlesinthisissueseepages4to12 .TheGroup’smembershiphasgrowntoaround2,000members.TheGrouphasalonghistoryof bringing activities to themembership and thewidercommunitywhich I amsurewill continuewell into thefuture. I thank the committee and those who haveparticipated in the diverse activities of ECG forvolunteeringtheirtime.

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 3

Chairman’s report for 2014 James Lymer (Wardell Armstrong)

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 4

The ECG Newsletter was first published for members of the RSC’s Environmental Chemistry Group (ECG) in January 1995, and renamed (for reasons the author can no longer remember) the ECG Bulletin in 2002. This twentieth anniversary issue provides a good opportunity to reiterate the rationale for providing this biannual publication and to review some of the content of the past forty editions.

In1994, the ‘EnvironmentGroup’ inaugurated in1972and lateraf iliated to theRSC’s IndustrialDivision wasrenamedthe‘EnvironmentalChemistryGroup’ af iliatedto the RSC’s Scienti ic Affairs Board . The irst issue ofthe ECG Newsletter Figure 1 explained this decisionand its implications. Also in that issue, a long‐servingcommitteememberandapastChairandTreasurer,GeoffDickes, reviewed the history of the EnvironmentGroupand some of the scienti ic meetings the Group hadorganised during the previous twenty years. Theseincluded the ECG Distinguished Guest Lecture DGL ,which remains a pivotal day in the Group’s scienti icpro ile.Fromits inception,thepublicationhashadanumberofobjectives:

TosummariserecentmeetingsorganisedbytheECG,andmeetingswithanenvironmentalchemistrythemehostedbysimilarorganisations;

TogivedetailsofforthcomingECGmeetingsandothersymposiainenvironmentalchemistry;

Toprovideaplatformfornewly‐quali iedPhDstudentstoreviewtheirresearchintotheenvironmentalsciences;

TodescribetheteachingofenvironmentalchemistryintheUKandinEurope;

Andtoallowthosewithaspecialisedknowledge,interestorconcernanopportunitytoreviewaparticulartopicintheenvironmentalsciences.

Other features in the publication have included bookreviews and details of books on the environment,toxicology, and health and safety acquired by the RSC

LibraryandInformationCentre.In 2009, Dr Adrian Kybett redesigned the ECG BulletinanditacquiredanInternationalStandardSerialNumberISSN . Printed copies of the ECG Bulletin from 2002onwards are available at the British Library in the StPancras Reading Rooms, London; two copies of eacheditionareheldbytheRSCLibraryatBurlingtonHouse.Becauseofincreasedcostsofproducinganddistributingprinted copies of the ECG Bulletin, the publication hasonlybeenavailabletomembersasanelectronicversionfrom July 2012 onwards. A few printed copies are stillproduced to publicise the ECG and to donate to theBritish and RSC Libraries. All copies of the ECGNewsletterandECGBulletinareavailableonlinewithoutcost or registration at www.rsc.org/Membership/Networking/InterestGroups/Environmental/ECGBulletin.asp.Furtherimprovementstothedesignbythe current editor Dr Julia Fahrenkamp‐Uppenbrinkallowquickeraccesstoindividualarticlesandfeaturesin

Anniversary article

ECG Newsletter and ECG Bulletin, January 1995 – January 2015 Rupert Purchase (Haywards Heath, rp@rupertpurchase.demon.co.uk)

Figure 1. The front page of the first edition of the ECG Newsletter, published in January 1995.

thewebversion.What have been some of the highlights of the pasttwentyyears? InJune1998,wefeaturedthe irstoftwocontributions by ECG member Michael Brooks on thecontamination of drinking water by arsenic inBangladesh and some available technologies for theremoval of this carcinogenic and toxicmetalloid. Otherarticlesonarsenicfollowed,discussingitsoccurrenceinother countries, mechanisms of toxicity, and arsenicspeciation see for example the July 2004 and January

2006 editions . Over the past decade, Professor JohnMcArthurandhiscolleaguesattheDepartmentofEarthSciences,UCLhaveunravelled someof the geochemicalfactors,whichleadtoarseniccontaminationindrinkingwater, as John McArthur explained in three issuesJanuary1999,January2009andSeptember2011 .Research associated with climate change and itsimplications for human habitation is perhaps of mostinterest for those who follow scienti ic developments,and the ECG has tried to re lect this interest in a

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 5

Year Chair Vice-Chair Secretary Treasurer 1994 1996 DrJohnHolder

UniversityofCentralLancashire

ProfessorC.Nico‐lasHewitt LancasterUniversi‐ty

DrRobertGemmill HMIP,Bristol

DrPeterO’Neill UniversityofPlymouth

1996 1997 ProfessorC.NicolasHewitt

DrJohnHolder DrMikeE.Jenkin AEATechnology,Abing‐don

DrPeterO’Neill

1997 1998 ProfessorC.NicolasHewitt

DrPeterO’Neill DrLeoSalter CornwallCollege,Redruth

DrTrevorPryce‐Jones† UniversityofHertford‐shire

1998 1999 DrPeterO’Neill ProfessorC.Nico‐lasHewitt

DrLeoSalter DrTrevorPryce‐Jones†

1999 2000 DrPeterO’Neill DrLeoSalter DrAndreaStroh UniversityofLeeds

DrTrevorPryce‐Jones†

2000 2001 DrLeoSalter DrPeterO’Neill DrAndreaStroh ProfessorPeterCraig DeMontfortUniversity

2001 2002 DrLeoSalter DrAndreaJack‐son néeStroh UniversityofLeeds

DrRobMacKenzie LancasterUniversity

DrBrendanKeely UniversityofYork

2002 2003 DrAndreaJackson DrLeoSalter DrRobMacKenzie DrBrendanKeely 2003 2004 DrAndreaJackson DrBrendanKeely

DrLeoSalter DrBrendanKeely

2004 2005 DrBrendanKeely

DrAndreaJack‐son

DrLeoSalter DrAndreaJackson

2005 2007 DrBrendanKeely

DrAndreaJack‐son

JoBarnes CornwallCollege,Redruth

DrAndreaJackson

2007 2008 DrBrendanKeely DrAndreaJack‐son

JoBarnes DrRubenSakrabani Cran ieldUniversity

2008 2009 DrBrendanKeely DrLeoSalter JoBarnes UniversityofWestEng‐land

DrRubenSakrabani

2009 2010 DrLeoSalter DrBrendanKeely JoBarnes DrRubenSakrabani 2010 2011 DrLeoSalter DrWilliamBloss

UniversityofBir‐mingham

JoBarnes DrRubenSakrabani

2011 2012 DrLeoSalter DrWilliamBloss JamesLymer WardellArmstrongLLP,Shef ield

JoBarnes

2012 2013 DrWilliamBloss DrLeoSalter JamesLymer JoBarnes 2013 2014 DrWilliamBloss JamesLymer DrMartinKing

RoyalHolloway,UniversityofLondon

JoBarnes

2014 2015 JamesLymer DrWilliamBloss DrMartinKing

DrJoBarnes

Year Chair Vice-Chair Secretary Treasurer 1994 1996 DrJohnHolder

UniversityofCentralLancashire

ProfessorC.Nico‐lasHewitt LancasterUniversi‐ty

DrRobertGemmill HMIP,Bristol

DrPeterO’Neill UniversityofPlymouth

1996 1997 ProfessorC.NicolasHewitt

DrJohnHolder DrMikeE.Jenkin AEATechnology,Abing‐don

DrPeterO’Neill

1997 1998 ProfessorC.NicolasHewitt

DrPeterO’Neill DrLeoSalter CornwallCollege,Redruth

DrTrevorPryce‐Jones† UniversityofHertford‐shire

1998 1999 DrPeterO’Neill ProfessorC.Nico‐lasHewitt

DrLeoSalter DrTrevorPryce‐Jones†

1999 2000 DrPeterO’Neill DrLeoSalter DrAndreaStroh UniversityofLeeds

DrTrevorPryce‐Jones†

2000 2001 DrLeoSalter DrPeterO’Neill DrAndreaStroh ProfessorPeterCraig DeMontfortUniversity

2001 2002 DrLeoSalter DrAndreaJack‐son néeStroh UniversityofLeeds

DrRobMacKenzie LancasterUniversity

DrBrendanKeely UniversityofYork

2002 2003 DrAndreaJackson DrLeoSalter DrRobMacKenzie DrBrendanKeely 2003 2004 DrAndreaJackson DrBrendanKeely

DrLeoSalter DrBrendanKeely

2004 2005 DrBrendanKeely

DrAndreaJack‐son

DrLeoSalter DrAndreaJackson

2005 2007 DrBrendanKeely

DrAndreaJack‐son

JoBarnes CornwallCollege,Redruth

DrAndreaJackson

2007 2008 DrBrendanKeely DrAndreaJack‐son

JoBarnes DrRubenSakrabani Cran ieldUniversity

2008 2009 DrBrendanKeely DrLeoSalter JoBarnes UniversityofWestEng‐land

DrRubenSakrabani

2009 2010 DrLeoSalter DrBrendanKeely JoBarnes DrRubenSakrabani 2010 2011 DrLeoSalter DrWilliamBloss

UniversityofBir‐mingham

JoBarnes DrRubenSakrabani

2011 2012 DrLeoSalter DrWilliamBloss JamesLymer WardellArmstrongLLP,Shef ield

JoBarnes

2012 2013 DrWilliamBloss DrLeoSalter JamesLymer JoBarnes 2013 2014 DrWilliamBloss JamesLymer DrMartinKing

RoyalHolloway,UniversityofLondon

JoBarnes

2014 2015 JamesLymer DrWilliamBloss DrMartinKing

DrJoBarnes

Table 1: Honorary RSC Environmental Chemistry Group Officers, 1995−2015

The names of institutions and the authors’ affiliations may have changed since the dates indicated.

measured and balanced way. Four articles on climatechange arising from an ECG DGL and Symposium,ClimateChangeanditsImpact,organisedatthestartofthismillennium,werepublished in the July2000 issue,including an article by Sir JohnHoughton on the likelyimpacts of climate change. Fifteen years later therelevanceofthesearticlesisstillapparent.Overtheyears,theECGDistinguishedGuestLectureandaccompanying symposium, held usually in March eachyearinLondon,hasprovidedplentyofinformativecopyfortheECGBulletin.TitlesofpastECGDGLsfrom1986onwardsmay be found at http://www.rsc.org/images/The‐ECGs‐Distinguished‐Guest‐Lecturers‐2014_tcm18‐185778.pdf.SpeakersattheseeventsareinvariablyverywillingtowritefortheECGBulletin.TheGrouphasalsobene itted for many years from LeoSalter’s detailed and luent writtensummariesoftheday’sproceedings.Changes in the composition of the ECGcommittee are re lected in other topicsselected for publication, notablyatmospheric chemistry andenvironmental chemistry in the Arcticand Antarctic regions. Committeemembers and atmospheric chemists, DrWilliam Bloss and Dr Stephen Ball havereviewed their work in atmospherichalogen chemistry ECG Bulletin, July2009 as well as providing detailedsummaries of theECGAtmospheric andEnvironmental Chemistry Forums,which they have organised for earlycareer researchers over the past fewyears see, for example, ECG Bulletin,

February2013 .ECGmemberProfessorEricWolff,FRSfromtheBritishAntarcticSurveywasthemainspeakerfor the ECG DGL and Symposium in 2007‘Environmental chemistry in the Polar Regions’ , andhis talkonpolar ice cores featured in theECGBulletin,July 2007 together with contributions from the otherspeakersatthisevent.Two articles have highlighted concerns about theenvironmental effects of xenobiotics. ProfessorsElizabethHillandCharlesTylerreviewedtheirworkontheidenti icationofendocrinedisruptorsinwastewateroutlets ECGBulletin, January2005 , and long‐standingECG committee member and ECG Bulletin Editor DrRogerReevedescribedsometechniquesusedtoremovepharmaceutical compounds found in sewage treatmentworks ECGBulletin,January2010 .This brief survey of the past twenty years cannot listevery contributor to the ECG Newsletter and ECGBulletin.Butperhapswecanconcludebymentioningtheproceedings of a joint ECG and RSC Historical GroupSymposium,whichwere published in the ECG Bulletin,January 2012. ‘Environmental chemistry: a historicalperspective’highlightedsomeofthescientistswho irstraisedconcernsaboutman’simpactontheenvironmentandlaidthefoundationofenvironmentalchemistryasadistinctscienti icdiscipline.Wehopethat theECGBulletinwillcontinueto lourish.Ideasandunsolicitedcontributionsarealwayswelcome.Please contact the ECG Bulletin Editors atecgbulletin@hotmail.co.ukforadvice.

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 6

The ECG committee in December 2014 at Burlington House. Front row: Zoë Fleming, Rowena Fletcher-Wood, Julia Fahrenkamp-Uppenbrink; middle row, Jo Barnes, Tom Sizmour, Bill Bloss, Martin King; back row, Steve Leharne, Ian Forber, Rupert Purchase, Roger Reeve, James Lymer.

1995 RupertPurchase,DelythForsdyke

1996 RupertPurchase,MegHeaton,DelythForsdyke

1997–2005

RupertPurchase

2006–2008

RupertPurchase,RubenSakrabani,JoBarnes

2009–2011

RupertPurchase,AdrianKybett,RubenSakrabani,RogerReeve

2011 RupertPurchase,CeciliaMacLeod,RogerReeve

2012–2013

JuliaFahrenkamp‐Uppenbrink,RupertPurchase,RogerReeve

2014– JuliaFahrenkamp‐Uppenbrink,RogerReeve,RowenaFletcher‐Wood

Table 2: ECG Newsletter and ECG Bulletin Editors, 1995-2015

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 7

As part of the ECG Bulletin’s twentieth anniversary edition, committee members reflect on the past and present of soil, air, and water quality management in the UK.

Introduction During the 20th and 21st centuries, society became afunctionofcapitalistideologies.Asaconsequenceofthis,consumerism is now a dominant and ubiquitousparadigm.Ifthisistrue,andsincethereisnoaltruismoraesthetic incapitalism,damagetotheenvironmentonlybecomesrelevantwhenitimpingesonpro it.Inmyviewthiscanoccurintwoways,eitherasacollateraleffectofthe pro it motive when a damaging action reducespro itability e.g.whenacommoditysuchaswateroroilbecomes so scarce/expensive that consumption isreduced or when government is provoked e.g. bypopularaction tointroducelegislation.Inrelationtothelatter, it is noteworthy that in capitalist societies,manyaspects of environmental legislation are justi iedeconomically, most often based on human healtharguments constructed around the costs to the state ofreduced economic activity and/or costs to nationalhealth systems. Legislation outside of these twocategoriesishard‐won.Arguments about the value, aesthetics, and long‐termsigni icance of the environment that cannotbe couchedin terms of economic value pro it rarely attract thegenuine commitment of governments.Without effectivelegislation by government, the preservation of theenvironment becomes a romantic and futile notion. Inother words, legislation is currently the only tool athumanity’s disposal that offers a route by which thecomplexity and wonder of the natural world can bepreserved; the introduction and implementation ofenvironmentallegislationisvital.I hope this personal view of the world we live in willsuf ice to introduce three brief surveys of the state‐of‐playofenvironmentallegislationwithregardtoland,airandwaterintheUKandEC;readersmaydrawtheirownconclusions about its effectiveness and whether it willsuf ice. Leo Salter

Contaminated land management IntheUK,throughout lateindustrialandpost‐industrialsociety, legislation began to re lect the need to protecthuman health and the environment from pollutionleading to a landmark regulation with the 1990Environmental Protection Act EPA . New policyinitiativesandvariouspiecesofspeci iclegislationwereintroducedfollowingenactmentoftheEPA.Prior to the EPA, and with respect to soils andcontaminated land, the Inter‐Departmental Committeefor the Development of Contaminated Land ICRCL,formed in 1976 provided various Guidance Notes onland contamination. These included a advice to LocalAuthoritiesagainstdevelopmentonland ill sites, b guidance onasbestos 1990 c trigger andintervention values for soilcontaminants 1987 to comparewith site concentrations aspartofanemerging,risk‐basedassessmentpractice that had developed overtheprevioustwentyyears.Following explosions in buildings on sites during the1980s,wheregroundgasaccumulationwasidenti iedasthe source, technical guidance was introduced.Establishinggroundgasconditionsoverthepasttwentyyears has become a common feature of landredevelopment.Today in the UK, land contaminated with pollutants isdealtwithbytwomainapproaches:1. Part II a of the 1990 EPA as amended addresses

contaminationpresentonexistinglanduses;and

2. The Local Authority Planning System, whichaddressescontaminationvialandredevelopment.

Part 2Aof the 1990EPA as amended was introducedunder Section 57 of the Environment Act 1995, and inthis,thestatutoryde initionofcontaminatedlandis“anylandwhichappearstothelocalauthorityinwhoseareaitis situated to be in such a condition, by reason of

Anniversary article

Environmental chemistry: a twenty year perspective Leo Salter (Cornwall), James Lymer (Wardell Armstrong), Jo Barnes

(University of the West of England), Cecilia Fenech (Cranfield University)

and Ian Forber (ALcontrol Laboratories)

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 8

substancesin,onorundertheland,that—a signi icant harm is being caused or there is asigni icantpossibilityofsuchharmbeingcaused;orb signi icant pollution of controlled waters is beingcaused, or there is a signi icant possibility of suchpollutionbeingcaused”.Through the 1990s, the common approach to assessingthe human health risks from land contaminationinvolved a simplistic approach of testing soil for ICRCLlisted contaminants and comparing soil concentrationswith ICRCL trigger values 1987 . Some practitionersalso derived in‐house values or adopted internationalvalues such as Dutch‐ or USA‐derived assessmentcriteria, but these values were not necessarily directlyapplicable in the UK. The ICRCL trigger values 1987 werewithdrawnin2002whentheEnvironmentAgencyEA began the publication of Soil Guideline ValuesSGVs . These are a key tool for generic assessment ofhealthrisksfromlandcontamination.SGVswerederivedusing an exposure model called CLEA. SGVs now formpart of a more comprehensive risk assessmentframework, along with largely industry derivedassessment criteria published since 2002 for soilcontaminants. Although signi icant progress has beenmade in contaminated land risk assessment since thewithdrawalofICRCLtriggervalues,withthelownumberofSGVsproducedandacurrentlullin theEAbackedSGVprogramme,practitioners are reliant ongenerating their own assessmentcriteria and/or purchasing valuesderived by other organisations.The maintenance of a generallyaccepted risk assessment datasetfor deriving generic assessmentcriteria is also a problem.Toxicitydata and physiochemical andexposure parameters can berevised over time, and thesechanges will affect generic health risk assessments oflandcontamination.Criteria used to assess surface water and groundwatercontaminants are usually adopted from drinking waterstandardsorEnvironmentalQualityStandardsforinlandand coastalwaters.Althoughmany contaminants foundin groundwater and surfacewater have an appropriatewater quality standard, this dataset could be enlarged.Many common contaminants, e.g. total petroleumhydrocarbons,donothaveaUKstandard.Today, the contaminated land risk assessmentframework, which has developed over several decades,

helpstoprotecthumanhealthandtheenvironmentfromsoilandgroundwatercontamination. Thereisscopeforimprovement, but it can be argued that practitionerstodayconductafarmorecomprehensiveriskassessmentof soil and groundwater contamination than twentyyearsago. James Lymer

Air quality management

1995was a pivotal year for air qualitymanagement intheUK,markingatransitionfromsource‐basedtoeffects‐basedstandards formanagingambientairquality.PartIV of the Environment Act 1995 set out the newlegislative requirements for the Secretary of State, theEnvironmentAgencyand local authorities in relation toLocalAirQualityManagement LAQM .Shortlyafter,theirst National Air Quality Strategy NAQS , published inMarch 1997, established health‐based standards foreight air pollutants benzene, 1,3‐butadiene, carbonmonoxide, lead, nitrogen dioxide, ozone, PM10particulatematterwithanaerodynamicdiameterof10μmor less and sulphur dioxide based on advice fromthe Expert Panel on Air Quality Standards EPAQS .ThesestandardsmirroredandwereamendedbyEUair

quality legislation in the form ofCouncilDirective96/62/ECanditssubsequent daughter directives,later consolidated into Directive2008/50/EC, to which MemberStateswererequiredtoadhere.Whereas industry and agriculturestillmakeasigni icantcontributionto localairpollution incontinentalEurope, in theUK themain source

is road traf ic. Over the pasttwenty years, the greatestemissions reductionshavebeen

forlead,sulphurdioxideandbenzene,achievedthroughfuelqualitystandardsimposedbytheEU,whichresultedin these pollutants being virtually eliminated fromvehicleemissionsby2001.Possibly themost importantfactor in reductions of nitrogen dioxide and PM10 hasbeen the adoption of European vehicle emissionstandards Eurostandards .Between1990and2011,UKNOxemissionsreportedlyfellby64%,largelyasaresultof new fuel and engine technologies. However, recentevidence suggests that those NOx estimates may havebeen overstated by as much as 25%. In the past tenyears,actualNOxandprimaryNO2emissions fromEurostandard vehicle classes have not fallen by asmuch astest‐track trials predicted. In addition, the greatest

Air pollution. Credit : Cornfield/Shutterstock

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2009 9

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 9

decreases in nitrogen dioxide expected with the latterEurostandardshavebeenconfoundedbyanincreaseinthe proportion of primary NO2 from diesel vehicles,effectively caused by the implementation of thesetechnologies and by the climate change policy taxincentivesthathaveultimatelyledtothelargegrowthindieselvehiclesintheUK.Atthesametime,epidemiologicalstudieshavebeguntoreveal thebreadthandseverityof thehealth impactsofair pollution beyond previously recognised respiratoryand cardiovascular effects. In October 2013, theWorldHealth Organization’s WHO International Agency forResearchonCancer IARC WorkingGroupunanimouslyclassi ied outdoor air pollution as carcinogenic tohumans, and in 2014, a large scale cohort study inEurope ESCAPE identi ied a broad range of airpollutionhealtheffects.IthasbeenestimatedthatintheUK, anthropogenic air pollution accounts for nearly29,000 deaths annually range 4,700 to 51,000 deaths and may reduce birth‐cohort life expectancy by anaverageof1to12months,presentingagreatermortalityburden than passive smoking or road traf ic accidents.Theseestimatesarebasedonlong‐termexposureto ineparticles particulatematterwithaerodynamicdiameterbelow2.5μm,PM2.5 andthereforelikelyunderestimatethe cumulative impact of other pollutants includingNO2 and of short‐term acute exposure. While PM2.5 isregulated forMember States under Directive 2008/50/EC, it is not currently a requirement for UK localauthoritiesunderLAQM.Although most regulatorygoalsforpollutantsregulatedunder national and EUlegislation have beenachieved in the UK over thelast twentyyears, thehealth‐based standards set for NO2are still widely exceeded intheUK,leadingtheEuropeanCommission to launch legalproceedings against the UKGovernment, on 20thFebruary2014,for“itsfailureto cut excessive levels ofnitrogen dioxide”. With theimmediate‘lowhangingfruit’of technological solutionsalreadypickedandrotted,inordertoimproveairqualityand avoid EC ines, the UK governmentmust now facesome politically unpalatable alternatives, includingreducing road traf ic dependence as part of a moreholistic,sustainableapproachtoairqualitymanagement. Jo Barnes

Water quality management In theUKandworldwide, the ieldofwatersciencehasseensubstantialchangesoverthepastca. twentyyears.Thesechangesarelargelyduetoincreasingawarenessofwaterpollutionanddemands forwaterprotection.Thissectionwillfocusonthreeaspectsrelatedtothe ieldofwater environmental chemistry that have resulted insome of the biggest changes in the ield: legislation,water monitoring methodology, and emergingcontaminants.In the past twenty years or so, changes to waterregulationswithintheUKhavebeenlargelydrivenbyEUlegislation. These include the adoption of the UrbanWaste Water Treatment Directive 1991 , the NitratesDirective 1991 , the Directive for Integrated Pollutionand Prevention Control IPPC 1996 , the DrinkingWater Directive 1998 , the Groundwater Directive2006 , and the Marine Strategy Framework Directive2008 .However, it iswithout doubt that themain in luence inEuropeanwaterpolicyhasbeen the introductionof theWaterFrameworkDirective WFD inOctober2000anditstranspositionintoUKnationallawthroughaseriesofregulations in2003.TheWFDencompassesmostof thedirectives mentioned above. Unlike traditional limitvalue approaches towater pollution, theWFDdoesnotset speci ic environmental quality standards and targetlimits. Rather, the directive focuses on means ofachievinga‘goodstatus’forallwaterbodiesintermsof

ecological and chemicalconsiderations, withoutspecifying target values.Additionally, it introducedthe concept of water bodymanagement on the basis ofriver basins, some of whichpass through severaladministrative and politicalborders.The ieldofwatermonitoringhas been driven not only bythe implementation of theseregulations, but also bysubstantial technological

improvements in water sampling and analysis. Watersamplinghasseenashifttowardproductioncontrolandpollution prevention through trend monitoring as pertheIPPCdirective andawayfromreactionarysamplingfollowingapollutioneventorothercauseforconcern.Anadditionalkeyshifthasbeentowardautomatedsamplingand online monitoring of water bodies, arising from

Water pollution. Credit: Armograph/Shutterstock

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 10

advances in such varied ields as micro luidics,electronicsminiaturisationandwirelesstechnologies.Inadditiontothesetechnologicaladvances,inrecentyears,the ield of water monitoring has also seen someinterestingshiftsawayfromtechnologicaladvancesandinto citizen science initiatives; for example, the OPAlwatersurveyasksrecreationalanglerstoreportwhethertheyhaveseenaspeci ictypeof ish.There has also been an increasing focus on ‘emergingcontaminants’, such as persistent organic pollutantsPOPs ,whichwerenotontheagendatwentyyearsago.This is evidenced, for example, by the adoption of theStockholm Convention on POPs in 2001 withimplementationintheUKinitiatedin2007 andtheUKWater Industry Research UKWIR ChemicalsInvestigationProgrammein2009;thelatterinvestigatestrace contaminant concentrations in UK wastewatertreatmentworksef luentsandisnowinitssecondphase.Inadditiontoregulatoryrequirements,advancesinmassspectrometric techniques, particularly tandem massspectrometric and high resolution techniques, haveundoubtedly been one of the main factors that haveallowedthisshifttooccur. Cecilia Fenech and Ian Forber

Further reading Introduction Someof these issuesarediscussed ina compendiumofbriefcommentarticlesinNature,515,27‐31 2014 andpp. 32‐33 ibid E. B. Barber, Account for thedepreciation of natural capital . For evocativedescriptions of the same phenomena, I suggest WolfTotem by Jiang Rong translated by Howard Goldblatt,Penguin Press, 2008 . Engineers of the Soul by FrankWesterman translated by Sam Garrett, Vintage Books,2010 discussestheimpactofcanalbuildinginthe1950son Turkmenistan and Kazakhstan. I also recommendRowing the Eternal Sea: the story of a MinamataishermanbyOiwaKeibo narratedbyOgataMasatoandtranslated by Karen Colligan‐Taylor, Rowman andLittle ieldInc,2001 .Contaminated land AnoverviewofregulationsregardingcontaminatedLandmay be found at www.york.gov.uk/info/200364/contaminated_land/490/contaminated_land. Technicalguidance is available at www.gov.uk/government/collections/land‐contamination‐technical‐guidance. Forinformationon theUSAperspective see www.epa.gov/superfund/about.htm.

For information on the Australian perspective seewww.public.health.wa.gov.au/3/1144/2/contaminated_sites.pm. The book Assessment andReclamation of Contaminated Land edited by R. M.Harrison,R.E.HesterandpublishedbytheRSCin2001 covers topics from the origins and extent ofcontaminatedlandproblems,includingeffectsonhumanhealth, through investigative measures, to speci ictechniquesofremediation.Air quality Barnes,J. 2014 Acriticalevaluationoflocalairqualitymanagement and its contribution to meeting the EUannual mean nitrogen dioxide limit value. PhD,UniversityoftheWestofEngland.R. Beelen et al., Effects of long‐term exposure to airpollution on natural‐cause mortality: an analysis of 22European cohorts within the multicentre ESCAPEproject.Lancet,383,785 2013 .S. D. Beevers, E. Westmoreland, M. C. de Jong, M. L.Williams, D. C. Carslaw, D.C. 2012 Trends in NOx andNO2 emissions from road traf ic in Great Britain,AtmosphericEnvironment,54,107 2012 .COMEAP 2010 The Mortality Effects of Long‐TermExposure to Particulate Air Pollution in the UnitedKingdom. Health Protection Agency. Environment Act1995.Chapter25. 1995 London:TheStationeryOf ice.J.W.S.Longhurst,J.G.Irwin,T.J.Chatterton,E.T.Hayes,N.S.Leksmono,J.K.Symons,Thedevelopmentofeffects‐based air quality management regimes, AtmosphericEnvironment,43,64 2009 .Water quality WaterFrameworkDirectiveInteractiveMapsforEurope:http://www.eea.europa.eu/themes/water/interactive/by‐category/wfdRapid Measurement Tools: ESKTN Business Case,https://connect.innovateuk.org/documents/2832130/6075062/Rapid Measurement Tools.pdf/e0646f10‐ef12‐42eb‐9477‐8eae26341665Europeanwaters–currentstatusandfuturechallenges–a synthesis, EEA Report No 9/2012, http://www.eea.europa.eu/publications/european‐waters‐synthesis‐2012

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 11

Article

Environmental chemistry degrees – then and now

Zoë Fleming (University of Leicester), Hattie Chisnall (University of Edin-burgh) and Jashvini Jothieswaran (University of Edinburgh)

On the twentieth anniversary of the ECG Bulletin, Group member Zoë Fleming reflects on her experiences as an environmental chemistry student at the University of Edinburgh from the mid-1990s. Two current first-year students of environmental chemistry at the same University also discuss their experiences, motivations and hopes for the future. A student’s reflections from twenty years ago In the early 1990s, it seemed tome that humanity hadinally admitted we were causing unnecessary harm tothe environment. From a teenager’s perspective, therewas an incredible feeling of hope and a belief in thepower to reverse this and join together to cleanupour

act. As awareness of environmental issues grew, wetalked our parents into recycling and buying eco‐products, tried toplant a treeor two, andpesteredourclassmates to stop using aerosol deodorant sprays.Wethoughtwecouldchangetheworld.The1992RioEarthsummit became the focus of our hopes. My choice ofdegreewassetuponreadingJamesLovelock’sTheAgesof Gaia: A Biography of our Living Earth and therealisationthatchemistrywasattheheartofthistheory.Environmental science degrees were growing inpopularity in the 1990s, but degrees in environmentalchemistrywereonlyofferedattwoorthreeuniversitiesin the UK. When I began to study environmentalchemistry at Edinburgh University in 1996, we were atiny minority among the chemists we joined for mostlecturecoursesandlabs.InpursuingthisdegreeIhopedto obtain the skills and chemical knowledge to fullyunderstand any damage to the environment caused byhumans and the chemical industry and to decipher thedisturbance of the intricate balances in our water, soilandair.Twentyyearson,environmentalchemistsarelessonthefringes of the key science questions. Today, we areneededtoadvisejustabouteveryindustry.Iamsurethatenvironmentalchemistrywillcontinuetogrowandplayakeyroleinenvironmentalprotection,andthatitwillbetaught within many other degree courses due to itsinterdisciplinary nature and broad relevance withinenvironmentalscience.

Zoë Fleming

Views of two first-year students today

Having grown up surrounded by the granite city ofAberdeen,theUK’sbiggestoilandgasmerchant,manyofmypeersaspired tobeapartof thisbooming industry,but this never really attracted me. Since deciding on adegree, I have realised that I want to be part of aprogression into something cleaner, healthier andfresher:renewableenergies.Iwanttodosomethingthatmakes a difference and I see cleaner energy as animportantfactorinourprogressiontoacleanerplanet.

Zoë Fleming assesses tree saplings for acid rain damage at CEH Edinburgh in the late 1990s.

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 12

My

generationhasalwayslivedwiththepressureto“reuse,reduceandrecycle”.Muchhasbeenachieved,butthisgenerationcanachievemuchmore.WeknowhowseriousthepressureontheEarthisnow,andI,likemanyothersmyage,wanttomakeachange.I feel that there is a general optimism aboutenvironmental chemistry. A lot has been achieved,including a greater awareness of environmental issuesamong businesses, and building hugewind turbines alloverthecountry.Thereisalotofenthusiasmforchangeandenvironmentalchemistrysupportsthatenthusiasm.There seems to be more understanding about whatenvironmental chemists can achieve now compared totwenty years ago, and there’s still that enthusiasm butnowweknowhowtogoaboutitabitmore.Ireallyenjoyedchemistryatschool.Ihadgreatteachersandalsoenjoyedreadingaboutthesubjectandgainingabetterunderstandingofhowalotoftheworldworked.IlikemydegreeandfeellikeIhavechosentherightone.It’sbeenfun indingmyfeetatuniversitysofar.IdonotknowwhatjobIwantafterUniversityandIwillprobablyleavethatdecisionuntilmyverylastyear.Rightnowit’sjust about getting a degree in something I really enjoy,whetheritgivesmemydreamjobornot. Hattie Chisnall

I think environmental chemistry is an important aspectofchemistry.Asscientists,weshouldbehelpingto indalternative ways to a more sustainable world. I ind itinteresting because it is a promising ield in science asournon‐renewableresourcesarestartingtorunlow.

WeonlyhaveoneEarthandshouldbedoingeverythingwecantosafeguarditratherthandestroyit.Wedohavebetterways to synthesise the sameproducts in amoreenvironmentally friendly way. And sometimes the‘greener’waycouldactuallyalsobemorecost‐effective.I

am

studyingenvironmentalchemistrysoIcanhelpinsomewayto indbetteralternativesforagreenerplanet.

Jasvini Jothieswaran

Courses for today’s environmental chemists Abriefwebsurveyofundergraduatedegrees apologiesif I have left any out! via www.whatuni.com revealsenvironmental chemistry degree courses at Lancaster,Bangor, Aberdeen, York and Edinburgh, all withemploymentratesofbetween81and90%.

AsanenvironmentalchemistrystudentwhofollowedmydegreewithachemistryPhD, Irealisedthat thereweremanyaspectsofenvironmentalscienceandmanagementthatwerenotincludedinmytraining.Knowledgeoftheinteractions between earth, water, and atmosphericchemistry and our responsibility as environmentalexperts is not a given and must be built up from realworld experience, reading up on the subject or furthertraining.

WhenIwaslookingforworkoutsidetheacademicsectora few years ago, I was told that a specialist Mastersdegreewouldbeextremelyhelpful toanenvironmentalscience professional. There is a huge array of suchMasters degrees, including Environmental, Analytical,Green, and Sustainable Chemistry titles as well asPollutionmonitoring, Toxicological, Contaminated land,Environmental Assessment, Management, Policy, andLaw among the ca. 700 advertised EnvironmentalMasters degree courses at www. indamasters.com.There is no a shortage of degree courses forenvironmental chemists to choose from today – so noexcusesnow!

Zoë Fleming

Hattie Chisnall in Edinburgh’s Meadows Jashvini Jothieswaran enjoying Loch Ness

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 13

Forthcoming meeting

New developments in the analysis of complex environmental matrices The Royal Society of Chemistry Environmental Chemistry Group and the Separation Science Group are holding this joint meeting on Friday 6th February 2015 at the Science Suite, Royal Society of Chemistry, Burlington House, Piccadilly, London. Programme 9.00 Registrationandcoffee9.50 Openingandwelcometomeeting Prof.GrahamMills,UniversityofPortsmouth,Portsmouth 10.00 Analysisof lameretardantsinindoordustandtheirmetabolitesinhumanlivercelllinesby OrbitrapTM‐MS DrMohamedAbdallah,UniversityofBirmingham,Birmingham 10.30 Useofmetabolomicsinsolvingenvironmentalproblems Prof.JakeBundy,ImperialCollege,London 11.00 Coffeebreak11.30 MonitoringofpolarpollutantsinsurfacewatersusingChemcatcher‐basedpassivesampling methods AnthonyGravell,NaturalResourcesWales,LlanelliLaboratory 12.00 Analysisofmarinebiotoxinsinshell ish DrAndrewTurner,CEFASWeymouthLaboratory, Weymouth 12.30 Pollutionbypolyisobutenes:astickyproblemforseabirds Prof.SteveRowland,Universityof Plymouth,Plymouth 13.00 Lunchbreakandvendors’exhibition14.15 Keynotelecture:LCtandemMSstrategiesfortheanalysisofcontaminantsofemergingconcernin water,soilandsedimentsamples Prof.DamiaBarcelo,CSIC,Barcelona,Spain 15.00 Aspectofdrinkingwaterquality–disinfectionbyproducts GavinMills,SevernTrentWaterLtd. 15.30 Screeningfornovelanti‐androgeniccontaminantsinenvironmentalsamplesusingmassspectrometry combinedwithbio‐assayprocedures Prof.ElizabethHill,UniversityofSussex,Sussex 16.00 NewdevelopmentsinGC/MSandGC/PIDinstrumentationforrapidon‐siteanalysisoftrace environmentalcontaminants DrAndrewHobson,QuantitechLtd.,MiltonKeynes 16.30 Meetingclose DrRogerReeve,UniversityofSunderland,Sunderland Members £90.00 and of BMSS or Chromatographic Society, discount code BMCM22 ; non‐members, £120.00;students,retiredmembers,andtheunwaged,£25.00

Registration http://www.rsc.org/events/detail/12079/new‐developments‐in‐the‐analysis‐of‐complex‐environmental‐matriceshttp://www.rsc.org/Membership/Networking/InterestGroups/separationscience/ForthcomingEvents.asp

Contacts ProfessorGrahamMills,UniversityofPortsmouth,Portsmouth,UKTel 44 0 2392842115,graham.mills@port.ac.ukDrRogerReeve,UniversityofSunderland,Sunderland,UK contactforlateregistrations Tel 44 0 1915152596,roger.reeve@sunderland.ac.uk

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 14

Theatmosphericconcentrationsofthemaingreenhousegases–carbondioxide CO2 ,methane CH4 ,andnitrousoxide N2O – continued to rise in 2013 and were at142%, 253%, and 121% of preindustrial levels before1750 bytheendof2013.ThisisoneoftheconclusionsofthelatestWMOGreenhouseGasBulletin,publishedon9 September 2014 1 . Now in its tenth year, theGreenhouse Gas Bulletin reports global observations oflong‐livedgreenhousegases.Carbon dioxide contributes around 65% to the overallradiative forcing by long‐lived greenhouse gases 2 .Between 2012 and 2013, the increase was the largestyear‐to‐yearincreaseinthirtyyears.Thereasonsforthislarger‐than‐averageincreaseremainunclear.Thereportconcludes,however,thatincreasedemissionsfromfossilfuelburningcannotexplaintheriseandthatchanges inthe exchange of CO2 between the atmosphere and theterrestrialbiospherefromoneyeartothenextprovideapossibleexplanation.The two other greenhouse gases that are discussed indetailaremethane,whichcontributes17%totheoverallradiative forcing by long‐lived greenhouse gases, andnitrous oxide, which contributes 6%. Both haveanthropogenic as well as natural sources, although formethane, anthropogenic emissions currently exceednaturalones.Recentmethaneincreasesafteranear‐zerogrowth ratebetween1999and2006have continued in2013andareattributedtorisingemissionsfromtropicalwetlandsandfrommid‐latitudeanthropogenicsources.Other greenhouse gases include the electrical insulatorsulphur hexa luoride SF6 , an extremely potentgreenhouse gas with a very long atmospheric lifetime.Although its contribution to greenhouse gas forcing iscomparatively small, SF6 data can help to evaluate theaccuracyofemissionsreportingandtovalidatechemicaltransport models. Finally, chloro luorocarbon andrelated compounds contribute 12% to radiative forcingbylong‐livedgreenhousegases.Forthe irsttime,theGreenhouseGasBulletinincludesasection on ocean acidi ication. The ocean takes uparound a quarter of anthropogenic emissions,measurably increasing the acidity of surface waters atmeasuring sites around theworld’s oceans. As a result,theocean’scapacityfortakingupmorecarbondioxideisreduced. The impacts of ocean acidi ication on marineorganisms,particularlycalcifyingorganisms,arelikelytobecomplexandarenotyetwellunderstood.Onlyafew

marine stations currently conduct carbon dioxidemeasurementsoverlongtimescales,greatlylimitingtheability to understand the impacts of carbon dioxideuptakeonoceanchemistry.

References 1. WMO Greenhouse Gas Bulletin GHG Bulletin No

10: The State of Greenhouse Gases in theAtmosphereBasedonGlobalObservationsthrough2013,availableatlibrary.wmo.int.

2. According to the IPCC, “Radiative forcing is ameasureofthein luenceafactorhasinalteringthebalance of incoming and outgoing energy in theEarth‐atmosphere system and is an index of theimportance of the factor as a potential climatechange mechanism.” Radiative forcing valuestypically refer to changes relative to preindustrialconditionsat1750.TheunitsareWattspersquaremeter W/m2 . See: http://www.ipcc.ch/pdf/assessment‐report/ar4/syr/ar4_syr.pdf.

The ECG Bulletin Editors

Update

WMO Greenhouse Gas Bulletin No 10

High altitude view of the Earth at night. As the latest WMO Greenhouse Gas Bulletin shows, greenhouse gas concentrations in the atmosphere continue to rise. The WMO publication also contains a section on ocean acidification as a result of rising atmospheric carbon dioxide concentrations. Credit: MarcelClem-ens/Shutterstock

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 15

Meeting report

Chemical atmosphere–snow−sea ice interactions: taking the next big step in field, laboratory and modelling Martin King (Royal Holloway, London, m.king@rhul.ac.uk)

An AICI (Air-Ice Chemical Interaction, www.igacproject.org/AICI) international workshop was held at Trinity Hall, Cambridge from 13 to 15 October 2014. AICI isasubdivisionoftheOcean–Atmosphere–SeaIce–Snowpack OASIS program of IGAC InternationalGlobal Atmospheric Chemistry . Previous AICIworkshops have produced in luential state‐of‐sciencereviews. For example, a Special Issue in AtmosphericChemistry and Physics www.atmos‐chem‐phys.net/special_issue275.html emerged fromanAICIworkshopheldatColumbiaUniversity,USAinJune2011 .

Therewereover70participantsfromover15countriesat the three‐day workshop, which followed on from asuccessful meeting in New York two years ago. Theaudience was mixed, with ield/lab and modellingexpertise fromatmospheric, sea iceand snowscientistsandbiologists.ThemeetingwasorganisedbytheBritishAntarctic survey with an international organisationcommittee including the author. The purpose of themeetingwas to review the current state of the scienceandproduceatwo‐pagereportonthestateofthescienceandhowtomove forward, for submission toScienceorNature.The irsttwodaysofthemeetingincludedreportsonthein luence of Arctic clouds mixed phase in the Arcticenergy budget, laboratory studies exploring theinteraction of ice with chemical constituents, the latestresults from central Antarctica and Greenland ieldcampaigns,andresultsfromseaicecampaignslookingathalogen compounds coming from sea ice. There werereports from the new sea ice facilities, and about thecomplexities of light and sea ice and the differentconsiderationsneededforphotochemistry,photobiology,andmodernclimatechange.TherewasevensomebriefdiscussionofMartianastrobiology.A substantial part of the workshop was spent indiscussionandtutorialsonnewopportunities,including

the creation of a new project in the Future EarthProgramme http://www.icsu.org/future‐earth , and avery useful session on how to get large EU projects offthe ground. In another session, station and ice breakerpersonnel reported on the capacities of their platformsand how to get on these platforms; this session wasparticularlyimportantforthoseattemptingtodoscienceon the platforms of another country. The closerintegration of modellers, laboratory scientist and ieldscientistswasanimportanttargetaswell.Trinity Hall was a fantastic location for the workshopthat includeda tasty formalmeal inCorpusChristiHall,followedbybeersintheinfamousEaglePub.

Icebergs in the glacier lagoon in Iceland Ekulsarlon. Credit: Sergemi/Shutterstock

A research vessel travels through sea ice in the Arctic. Credit: Kldy/Shutterstock

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 16

ECG committee member Ian Forber is the Deputy Technical Manager at ALcontrol Laboratories (Hawarden) and the ECG’s web pages co-ordinator. Here he tells us about his career as an environmental chemist.

What inspired you to become a scientist? I had an interest in and anaptitude for the sciencesandmathematics at school.When I inished full timeeducation I very nearlybecame a bank cashier.InsteadIchosetoworkinalaboratory attached to a

metalre inery.Aspartofthejob,Iwassenttocollegeonday release to study chemistry through the BTEC NC/HNC system and inally on to university. It was duringthis time that I realised that chemistry is a lot moreinterestingthanbanking.

How did you come to specialise in inorganic analytical chemistry? Inmy irstjob,wemostlyanalysedmetalsandmetalresidues.ThissuitedmewellasIhavealwaysbeenmoreinterestedinthe areas of chemistry involving formulae andcalculations with a precise result. My interest in theenvironmental aspects of chemistry developed fromdealing with the Environment Agency following theintroduction of Integrated Pollution Control IPC Regulations in the mid‐1990s. When the opportunitycameuptoworkasatechnicalspecialistatALcontrol,alaboratory specialising in environmental analysis, Ijumped at the chance towork somewheremore closelyinvolvedinenvironmentalconcerns.

Could you describe your current job? ALcontrol is a multinational contract laboratory withover 60 laboratories across Europe. The laboratory IworkforistheUK’scontaminatedlandandnon‐potablewatersdivision.Aspartof the technical team, Idevelopandvalidatenewanalyticalmethods,helptosupportandimprove current methods used in routine productionanalysis, and resolve customer queries. The technicalteamalsoundertakesnon‐routineprojectsforcustomers,

giving us a chance to think creatively. As DeputyTechnicalManager,IalsosupporttheTechnicalDirectorandcoverforhimwhenrequired.

What advice would you give to anyone considering a career in environmental chemistry? Itcanbearewardingcareerifyouhaveagenuineinterestinthesubject.Beingtrulyinterestedwillhelpyougofurtherinany ieldandfeelmoreful illedinyourwork.EnvironmentalchemistrycoverssuchawidescopethatIwouldsuggestkeepingyouroptionsopenasyou start your studies until you ind an area that bothsuitsandinterestsyou.

What are some of the challenges facing the environmental chemistry community? Fromananalyticalpointof view therearealwaysmorecompounds of environmental interest coming throughthat will usually need novel analysismethods. There isalso constant pressure to lower limits of detection asregulations get tighter. For instance, the EU WaterFramework Directive WFD looks for lower limits ofdetectionforsomecompoundsanddifferentassessmentapproachesforothercompounds.

Traditionally, analysis has aimed to determine the totalamountsofcompoundsintheenvironment.Today,closerattention ispaid to the impact levelsof compoundsandto which forms of particular compounds are mostecologically toxic. This requires, for example, speciationtesting and measurement of bioaccessible levels in theenvironment. The resulting challenge for theenvironmental analytical community is to develop evermorecomplexanalyticaltechniques.

What is the most rewarding aspect of your career so far? There have been severalrewarding times inmy career. One that comes tomindwas a few years ago when I was asked to join theEnvironment Agency’s Standing Committee of AnalystsSCA todevelop their ‘BlueBook’ standardmethod fortheanalysisofcyanidesinsoils.

If you weren’t a scientist what would you do? Iwouldprobablyhavepursuedacareerinbankingoraccounting.Imighthaveabettersalary,butIamgladthat I chose a career that challenges me on an almostdailybasis.

ECG Interview

Ian Forber

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 17

Perceived to be in competition with hunters and to prey on livestock, predators in Europe and Africa are deliberately poisoned via carcass baits laced with agricultural pesticides. As communal scavengers, vulture populations in these areas have been especially hard hit by the presence of poison-laced carcasses. Species that migrate between Europe and Africa face poisoning risks in either region. Residues of veterinary agents in the carcasses available to vultures, especially in Europe, are also of concern.

Europe has a long history of poisoning wildlife. Inparticular,predatorsthatareindirectcompetitionwithhunters and may prey on livestock, are generallymaligned. As communal scavengers, vultures have beenhit particularly hard and have even been directlytargeted because of the belief that they prey on younganimals.Followingseveredeclinesofpopulationinbirdsofprey forexampletheImperialEagle,theRedKite,andCinereous and Egyptian Vultures , anti‐poaching andanti‐poisoning initiativeshavebeen implemented in theEU over the past decade, but these problemsnevertheless persist 1 . In Africa, deliberate poisoningofwildlife has been documented for hundreds of years2 .WhenAfrica’shumanpopulationbegantoexplodeinthe 1980s, the increasing need for agricultural andgrazing lands exacerbated con lict between people andwildlife, especially carnivores 3 . The commodi icationof Africa’s natural resources also began in earnestaround this time. All these factors led to an increase in

Article

Veterinary agents and poisons threaten avian scavengers in Africa and Europe Ngaio Richards (Working Dogs for Conservation, Three Forks, Montana, USA; ngaio@workingdogsforconservation.org) and Darcy Ogada (The Pere-gine Fund, Nairobi, Kenya; darcyogada@yahoo.com)

Vultures under threat. A Griffon vulture lands to join others at a feeding station. The vultures are under threat both from deliberate poisonings and because they are highly susceptible to veterinary agent diclofenac used in livestock. The image on page 18 shows Griffon vultures feeding on meat provided at the same station.

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 18

wildlife poisoning, particularly with agriculturalpesticides,apracticethatcontinuestoday 3 .Addedtothese deliberate poisonings, there is a new threat fromveterinaryagentsthatarehighlytoxictovultures.Thus,avian scavengersmigrating between Europe and Africafacetheprospectofpoisoningineitherregion.

Threats to vultures in Europe In 2013, the nonsteroidal anti‐in lammatory drugNSAID diclofenac, which nearly drove three Gypsvulture species to extinction inAsia 4 ,was registeredfor veterinary use in Spain, Italy, and several other EUcountries 5, 6 . Given that Spain is themainEuropeanvulturestrongholdandthatpopulationsofsomespeciessuch as the Egyptian andBearded vultures inEurope arefaltering, the drug’s presence onthe veterinary market isperplexingandtroubling.Sharmaet al. 7 recently showed thatdiclofenac isalso toxic toSteppeEagles, raising additionalconcerns forAquila eagles suchas the ImperialEagle andotheravianscavengers.Other NSAIDs e.g. lunixin andketoprofen showntobetoxictovultures and other birds 8 arealsoregisteredforveterinaryuseinEurope 9 .Residuesof these and various other veterinary agents e.g.antibiotics and euthanasia drugs are therefore alsopotentially available to avian scavengers in livestockcarcasses,whetheratspeciallymanagedfeedingstations,in captive/rehabilitation facilities, or in remote ruralgrazingareaswhereanaffectedanimalcannotreadilyberetrieved after death. The potential repercussions oftheseotherNSAIDswarrantfurther investigation 8,9 ,buttherelativethreats orlackthereof intheEuropeanUnionhavenotyetbeenestablished 10 .Andwhilethecampaign against deliberate wildlife poisoning inSouthern Spain is providing affected populations withtemporary respite, this is still very far fromresolved.Atwo‐pronged response is still needed to addressdeliberate exposure to poisons and also non‐deliberateexposuretoveterinaryagents.

The situation in Africa In Africa, deliberate wildlife poisoning has beenimplicated in population‐level declines in largecarnivores, raptors, and vultures, particularly insouthern and East Africa 3 . Scavenging species e.g.lions,hyenas,jackals,vultures,andeagles havebeenthe

mostimpacted 3 ,withpoisoningbeingthemaindriverin 60%ofvulturedeclinesoverthepast30years 11 .During 2013, known vulture poisonings exceeded 2000individuals—thehighest iguretodateandlikelyagrossunderestimate, because most poisoning incidents areneverreported 3,11 .Therecentsurgeinelephantandrhino poaching using poisons and the associatedpoisoning of vultures likely represents one of themostimportant new threats to African vultures, one that islittlereportedevenamongconservationists.There is also increasing concern about the use ofveterinary diclofenac and other NSAIDs in livestock inAfricaandtheirpotentialtoharmAfricanvultures 12 ,particularly in South Africa, where vulture‘restaurants’ feeding stations are comparatively

abundantandstockedprimarilywith the carcasses of deadlivestock 13 .Elsewhereonthecontinent, the NSAID threat tovultures is probably lowbecause of believed minimaluseofNSAIDsinlivestock.Evenwhere NSAIDS are used, thelikelihoodofvulturesfeedingona treated carcass is smallbecause dead livestock tends tobe consumed by people D.Ogada personal observation .However, residues in domestic

animalskept for transportation e.g.horses,camelsanddonkeys thatmaynotbeeatenupondeathmuststillbeveri ied.

Exposure to veterinary agents versus deliberate poisoning Theterm“poisoning”isnowfrequently and,atleastforthepresenttime,misleadingly usedinconjunctionwiththeexposureofvulturesandotherspeciestodiclofenac.The drug is highly toxic to Old World vultures, whichsuccumb to visceral gout after ingesting residuesaccumulated in the tissues of animals administered thedrug during veterinary treatments. Other oftenmammalian scavengersappeartobefarlesssusceptibleto the drug. The key point is that any ensuing harm tovultures and other susceptible scavengers exposed todiclofenac‐containing carcasses is unintentional. Bycontrast, ina “true”poisoningcase,carcassesandotherdesirablefooditems dependingontheintendedwildlifetarget are intentionally laced with potent compoundssuch as strychnine, aldicarb, carbofuran, orchlorfenvinphos – anything that is readily available,highlyeffective,andinexpensive.Allofthesecompoundsareacutelytoxicandindiscriminatelykillanyanimalthat

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 19

feedsonthebait.The availability of potentially toxic veterinary drugresidues in livestock carcasses and that of toxiccompounds deliberately added to carcasses and otheredible luresare, fornow, twodistinct threats, requiringdifferent investigatory and remedial approaches.However, if would‐be poisoners in European countrieswherediclofenachasbeenregisteredrealizeitspotencytovultures,theymayadoptit,orotheravailableNSAIDs,as a poison. If this happens, the line betweenunintentional intoxication and deliberate poisoningwillbeblurred,andwildlifeforensicinvestigationswillhaveto be adapted accordingly. This concern should also beproactively extended to other veterinary agents thathave been shown to harm scavengers feeding onpreviouslytreatedlivestockcarcasses 15 .In both Europe and Africa, the deliberate poisoningmenace to predatory and scavenging wildlife isparticularly pressing, as several populations are beingdriven towards extinction. Local wildlife poisoningsundermine national and international conservationefforts.Thecurrentsurgeintheuseofpoisonstopoachelephants and rhinos is extremely worrying. Theslightest additional threat, in this case in the form ofavailabletoxicresiduesofveterinaryagents,canplaceanunsustainable strain on an already plummetingpopulation. Concerted and sustained vigilance andmonitoring of all veterinary agents known to be in useand potentially harmful is of utmost importance.Understanding the relative magnitude of, and inherentcomplexitiespresentedby,eachlikelythreatisessentialto enacting stringent legal procedures and determiningpenalties in the ongoing battle to safeguard scavengingwildlife and the critical ecosystem balance they helpmaintain.

Acknowledgements WethankJoseRafaelGarrido,AlvaroCamiña,andRafaelMateo for their feedback regarding the situation inEurope. We thank Iñigo Fajardo for providing thephotographs of Griffon vultures at El Picacho Vulturefeeding station, Cadiz Province, Andalucia, Spain. Thefeedingstationisrunforconservationpurposes.

References

1.Fajardo Ruiz et al., in Carbofuran and WildlifePoisoning: Global Perspectives and ForensicApproaches, N. L. Richards, Ed. Wiley, Chichester,UK,2011 ,Chapter5,pp147‐155.2.H.Stadler,inPreventionistheCure.Proceedingsofa workshop on holistic management of human‐wildlife con lict in the agricultural sector of South

Africa,B.Dalyetal.,Eds. EndangeredWildlifeTrust,Johannesburg,SouthAfrica,2006 ,pp11‐16.3.D.L.Ogada,Powerofpoison:pesticidepoisoningofAfrica’swildlife,AnnalsoftheNewYorkAcademyofSciences10.1111/nyas.12405 2014 .4.J.L.Oaksetal.,Diclofenacresiduesas thecauseofvulture population decline in Pakistan, Nature, 427,630 2004 .5.A. Camiña, J. R. Garrido, J. Martin, C. H. Lopez‐Hernández, R. Alfaro, A new threat to Europeanvultures,Science,344,150 2014 .6.A. Margalida, J. A. Sanchez‐Zapata, G. Blanco, F.Hiraldo,J.A.Donazar,DiclofenacapprovalasathreattoSpanishvultures,Cons.Biol.,28,631 2014 .7.A.K.Sharmaetal..DiclofenacistoxictotheSteppeEagle Aquila nipalensis: widening the diversity ofraptors threatened by NSAID misuse in South Asia.BirdConservationInternational,24,282 2014 .8.R.Cuthbert, J. Parry‐Jones,R.E. Green,D. J.Pain,NSAIDs and scavenging birds: potential impactsbeyond Asia’s critically endangered vultures.BiologicalLetters,3,91 2007 .9.Commission Regulation EU No 37/2010 of 22December 2009 on pharmacologically activesubstances and their classi ication regardingmaximum residue limits in foodstuffs of animalorigin, Of icial Journal of the European Union L15,pp1‐72 2010 .10.R. J. Cuthbert et al., Assessing the ongoing threatfrom veterinary non‐steroidal anti‐in lammatorydrugstocriticallyendangeredGypsvulturesinIndia,Oryx,45,420 2011 .11.N. L. Richards et al., Merging wildlife andenvironmentalmonitoring approacheswith forensicprinciples: application of unconventional and non‐invasive sampling in eco‐pharmacovigilance, Journalof Forensic Research, 10.4172/2157‐7145.10002282014 .12.D. L. Ogada et al., Another continental vulturecrisis:Africa’s vultures collapsing towardextinction,inpreparation.13.V. Naidoo, K. Wolter, R. Cuthbert, N. Duncan, N.2009. Veterinary diclofenac threatens Africa’sendangered vulture species, Regulatory ToxicologyandPharmacology,53,205 2009 .14.M. D. Anderson, S. E. Piper, G. E. Swan, Non‐steroidalanti‐in lammatorydruguse inSouthAfricaand possible effects on vultures, South AfricanJournalofScience,101,112 2005 .15.K. O’Rourke, Euthanatized animals can poisonwildlife: Veterinarians receive ines, Journal of theAmerican Veterinary Medical Association, 220, 1462002 .

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 20

Forthcoming meeting

Emerging contaminants in waters and soils, practical considerations: sampling, analysis and consequences

The RSC’s Environmental Chemistry Group, Water Science Forum and International Network of Environmental Forensics Group will hold this joint meeting on 4 March 2015 at The Source Skills Academy, Sheffield, S9 1EA

Programme 09:50 RegistrationandRefreshments10:20 WelcomeandIntroduction,KevinPrior,Chair,WaterScienceForum10:30 RakeshKanda,BrunelUniversity11:00 GrahamMills andAnthonyGravell ,PortsmouthUniversityandWelshEA11:30 MariaRomero‐Gonzalezetal.,UniversityofShef ield12:00 Lunchandposterviewing13:00 MarianneStuart,BritishGeologicalSurvey13:30 BarbaraKasprzyk‐Hordern,UniversityofBath 14:00 ZulinZhang,JamesHuttonInstitute14:30 Refreshmentbreakandposterviewing15:00 ChristineSwitzer,UniversityofStrathclyde15:30 SimonParsons–WinneroftheRSCSustainableWaterAwardfor201416:00 Discussion16:30 MeetingclosesTheorganisersgratefullyacknowledge thesupportof theRoyalSocietyofChemistry’sEnvironment,SustainabilityandEnergyDivisionCouncilforsponsorshipoftheawardtoProfessorSimonParsons.

Booking http://www.rsc.org/events/detail/16644/emerging‐contaminants‐in‐waters‐and‐soils‐practical‐considerations‐sampling‐analysis‐and‐consequenceshttps://www.eventbrite.co.uk/e/emerging‐contaminants‐in‐waters‐and‐soils‐practical‐considerations‐sampling‐analysis‐and‐tickets‐13548480871

Organizing committeeKevinPrior RSCWaterScienceForum

JamesLymer RSCEnvironmentalChemistryGroupandWardellArmstrongShef ield

CliveThompson RSCWaterScienceForumandAlcontrol

RichardAllan RSCWaterScienceForumandCobaltSolutions

StephenMudge InternationalNetworkofEnvironmentalForensicsandExponent

Contact for further details KevinPrior kevin@thackie.co.uk

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 21

The atmospheric concentration of a trace gas is determined by the balance between its sources and sinks. However, the sink processes alone determine the lifetime (residence time) of the gas in the atmosphere. This Environmental Brief outlines how lifetimes are calculated and presents some caveats about their interpretation. Many trace gases are emitted directly into theatmosphere Figure 1 . Examples for these primaryemissions include nitrogen oxides NOx NO NO2 from fossil fuel combustion and vehicle exhausts, andhydrocarbons of both biogenic and man‐made origin.Primaryemissionsgenerallyenter theatmosphere fromsources locatedon theEarth’s surface, and so thisBriefconcentratesontroposphericchemistry.Asecondsubsetof trace gases is generated in situ by chemical andphotochemical processes within the atmosphere: forexample, tropospheric ozone is a secondary pollutant.Trace gases are removed by various sink processes.Reactivespecies suchasozone orsolublespecies suchasnitricacid aredepositedbycontactwiththeground;carbon dioxide is taken up by plants. A few chemicallyimportant molecules notably ozone and NO2 undergophotolysis in the troposphere 1 . However, the mainsinkformosttracegasesisreactionwithatroposphericoxidant such as OH or NO3 radicals 1, 2 . Only thosecompoundsthatdonotphotolyseanddonotreactwithtroposphericoxidants ordosoonlyslowly persistlongenough to be transported into the stratosphere,

chloro luorocarbonsbeingpertinentexamples.

Lifetimes Tounderstandtheconceptofalifetime,consideratracegasthatisremovedfromtheatmosphereviaasinglesinkprocess characterised by a irst‐order rate coef icient kwithunits1/time .Supposealsothatthesinkbalances

thesourcesofthistracegas,soitsconcentrationisstableFigure 2 . Next, suppose that an instantaneous, extrapulse of the trace gas P0 enters the atmosphere: thisoccursatYear2inFigure2.Theamountofextragasissosmall that it does not perturb other atmosphericprocesses. After the pulse, the excess concentration Pdecays exponentially with time as the concentration ofthetracegasre‐establishessteady‐state: P P0exp kt eq.1 Recastingeq.1intermsofadecaytimeconstanttgives P P0exp t/τ eq.2 Thustheatmosphericlifetimeofthegasistheinverseofthe irst‐orderratecoef icientforitssinkprocess: τ 1/k eq.3 Figure2illustratesanotherimportantresult.Theamountofextragasemittedisthesameinthetwocasesshown,butwhereastheshort‐livedgasessentiallyre‐establishesits steady‐state concentration within ive years of theemission event, the effects of the long‐lived gas persistfor decades. It is no coincidence that the majorgreenhouse gases CO2, CH4 and N2O implicated inanthropogenicclimatechangearelong‐lived.The same concept can be applied to a trace gas withmultiplesinks,exceptnowtheratecoef icientisthesumof the irstorderratecoef icientscharacterisingeachofthevarioussinkprocesses,asgiven ineq.4.Byanalogywith eq. 3, the overall atmospheric lifetime is given bythe reciprocal of the sum of the reciprocal lifetimes foreachsinkprocess eq.5 .Notethattheoveralllifetimeisnecessarily shorter than even the shortest lifetime

ECG Environmental Briefs (ECGEB No 7)

Atmospheric lifetimes of trace gases Stephen Ball (Department of Chemistry, University of Leicester,

sb263@leicester.ac.uk)

Figure 1: A summary of atmospheric sources and sinks. Note that this particular model neglects physical transport of trace gases into and out of the central box.

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 22

characterisingthefastestsinkprocess. Ktotal k1 k2 k3 … eq.4 1/τtotal 1/τ1 1/τ2 1/τ3 … eq.5 Forexample,methyl chloroform CH3CCl3 has lifetimesof6.0yearsforlossbyreactionwithOH,38yearsforlossintothestratosphereand94years fordepositiontotheocean 3 .1/τtotal 1/6.0 1/38 1/94 0.204year 1andsotheoveralllifetimeisτtotal 1/0.204 4.9years.

Chemical loss Therate‐limitingstepintheatmosphericdegradationofverymanytracegasesistheirreactionwithOHradicalsduringtheday.ThelifetimeofatracegasAwithrespecttoreactionwithOHis τOH 1/ kOH OH eq.6 where kOH is the rate coef icient for the second‐orderreactionA OHproductsand OH istheatmosphericconcentration of OH radicals. An analogous expressionprovides the lifetime for oxidation by NO3 radicals atnight.Reactionwith ozone and chlorine atoms can alsosometimesinitiateoxidationoftracegases.For example, OH reacts with isoprene emitted byplants with a rate coef icient kOH 1.0 x 10 10molecule 1 cm3 s–1 at 298 K 4 . Assuming an averageOH of 2 x 106 molecules cm–3 during daylight 12hours ,eq.6yieldsτOH 1.4hours.NotehereτOHistheday‐timelifetimeofisoprene’slossviaOH:atnight, OH is zero and τOH is thus inde inite. Isoprene also reactswithNO3 kNO3 7.0x10 13molecule 1cm3s–1at298K4 .Eq.6givesτNO3 0.8hoursassuming NO3 5.0x108moleculescm–3atnight 12hours .Since NO3 iszeroindaylight 2 ,τNO3isinde initeduringtheday.Themeanlifetimeofisopreneoverthe24‐hourdiurnalcycleis 1.1hours.

CaveatsThe simpleanalysisoutlinedabovehas someproblems.Inparticular,eq.6predictsthelifetimeofmethanetobe5.0yearsusingkOH 6.4x10 15molecules 1cm3s–1at298K 4 andarepresentative24‐houraverageof OH 1x106moleculescm–3. Methanedoesnotreactwith

NO3 . However, methane’s lifetime for OH oxidation iswidely accepted to be a factor of two longer: e.g. 9.7years 5 . The discrepancy arises in part from havingusedthe298Kratecoef icient ineq.6.ReactionsofOHor NO3 with hydrocarbons have an activation energybarrier, and hence the rate coef icients decrease withdecreasing temperature 4 . Outside of equatorialregions and summertime temperate regions,temperaturesarebelow298Kandmethane’slifetimeis

correspondingly longer. Vertical mixing of methane tohigher and hence cooler altitudes also considerablyprolongsitslifetime 5 .AnothermajorissueconcernswhatOHconcentrationtouseineq.6.OHconcentrationspeakaroundmiddayandtailofftozeroatsunriseandsunset;theassumptionofaconstantmeanOHconcentrationisagrosssimpli ication.OHconcentrationsalsovarywiththeseasonsduetothedifferences in solar zenith angles and the number ofhours of daylight. In practice, methane’s atmosphericlifetime isnegligibly in luencedbydiurnal and seasonalvariations in OH because methane is suf iciently long‐lived for these effects to average out 5 , but such OHvariations are important for shorter‐lived species.Methane’s lifetime instead depends on latitudinalvariationsinOH,andequatorialregionshavethehighestOH concentrations. These factors, allied to thetemperaturedependenceof theOH CH4reactionrate,resultin60%ofglobalmethanebeingoxidisedbetween30°Sand30°Nataltitudesbetweenthegroundand5km5 . The global atmospheric lifetime ofmethane is bestestimatedfromaweightedaverageofmethanelifetimescalculatedoverdifferentlatitudesandaltitudes.

References

1.M.King,Calculatingphotolysisratesandestimatingphotolysislifetimes,EnvironmentalBrief#1,EGCBulletin,July2013,p.21.2.S.Ball,Atmosphericchemistryatnight,EnvironmentalBriefNo3,EGCBulletin,January2014,p.18.3.R.G.Prinnetal.,Geophys.Res.Lett.32,L078092005 .4.R.AtkinsonandJ.Arey,Chem.Rev.103,46052003 .Seealsohttp://iupac.pole‐ether.fr/.5.M.G.Lawrenceetal.,Atmos.Chem.Phys.1,372001 .

Figure 2: Concentration-time profiles for gases with lifetimes of 1 and 10 years.

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 23

As part of the UK Air Quality Strategy, Local Authorities are legally obliged to assess atmospheric NO2 concentrations (and those of other specified air pollutants). The best method for measuring ambient NO2 concentrations is the chemiluminescence analyser, providing real-time data at high precision. However, the analysers are expensive and need power and security at the operating site. Local Authorities therefore continue to take advantage of the simplicity and low cost of passive diffusion tubes (PDTs) to assess NO2 concentrations across a spatial network. This Brief explains how PDTs work and describes some of their limitations. Principles of PDT methodology The passive samplers used inthe UK are of the tube designirst introducedbyPalmesetal.in 1976 1 Figure 1 . Theyconsist of 7.1 cm‐long acrylicplastic tubes, with an internalcross‐section of 0.92 cm2, withthe NO2 absorbenttriethanolamine N CH2CH2OH3, TEA coated onto twostainless steel grids in theinternalend.TEAisassumedtobe 100% ef icient at facilitatingthe 1:1 conversion of NO2molecules into nitrite NO2

anions.Samplers are typically exposed just above adultbreathing height, with the open end of the tube facingdownward to avoid rain ingress for a period of 1‐4weeks. At the end of the exposure the tubes arerecapped. The nitrite in the TEA is subsequentlyextractedinthelaboratoryintoaknownvolumeofwaterandquanti iedeitherdirectlybyionchromatographyorby a colorimetric procedure. The latter involves addingsolutions of sulphanilamide and N‐ 1‐naphthylethylenediamine NEDA to form a pink dye; theabsorbance intensity of this dye measured at awavelength of 540 nm is proportional to the nitriteconcentrationintheextractedsolutionandhencetotheamountofNO2capturedbythesamplerduringexposure.ThePDToperatesthroughthediffusionofNO2moleculesdown the concentration gradient set up between theconcentrationintheambientairatthemouthofthetubeand the TEA absorbent. Assuming zero NO2concentration in the air just above the absorbent, theconcentrationgradientis NO2 av/L,where NO2 avistheaverage concentration at themouth of the tube duringexposureandListhelengthofthetube.Foranexposuredurationt,thetotalamount,Q,ofNO2collected asNO2‐

ECG Environmental Briefs (ECGEB No 8)

How do passive diffusion tubes measure NO2 concentrations? Mathew R. Heal (School of Chemistry, University of Edinburgh, m.heal@ed.ac.uk)

Figure 1: Schematic of a Palmes-type passive diffusion tube, and an example deployment (photo from Gradko International Ltd.).

Royal Society of Chemistry—Environmental Chemistry Group—Bulletin—January 2015 24

isgivenby: Q NO2 avADt/L eq.1 whereA is the internal cross‐sectional area of the tubeand D is the diffusion coef icient for NO2 in air. Re‐arranging gives the expression for the average NO2concentrationduringexposureas: NO2 av QL/ADt eq.2 ThevalueofDrecommendedby theUKworkinggroupconvenedonbehalfofDefratoreportonharmonisationof NO2 passive diffusion tube PDT procedures is0.151cm2s‐1 2 .

Limitations of PDT performance TheinherentsimplicityofthePDTmethodmeansthatitsprecision and accuracy cannot in general comparewiththat of a chemiluminescence analyser. A number offactorsmayin luencebothprecisionandaccuracyofNO2concentrations derived from PDT data 2, 3 . Factorsthat may in luence NO2 PDT performance include thefollowing,atdifferentstagesofaPDTmeasurement:1.In PDT preparation: the mass of TEA applied to thegrid; the choice of solvent water or acetone used toapplyTEAabsorbenttothegrids;andwhethertheTEAisapplied by dipping grids in the TEA:solvent solution orbypipettingthesolutiondirectlyontothegrids.2.In PDT exposure: humidity and temperature of theambientenvironment;airturbulenceatthemouthofthetube during exposure which can shorten the effectivediffusionpathlength, leadingtosystematicpositivebiasin theNO2concentration ;productionofadditionalNO2in the tube by reaction of co‐diffusing NO and O3 aconsequenceoftheopacityofthestandardacrylictubesto NO2 photolysis wavelengths , again leading tosystematic positive bias 4 ; and degradation of thenitrite‐TEA complex during exposure, leading tosystematicnegativebias.3.In PDT analysis: the concentrationof the colorimetricreagents; and degradation of the dye between itsformationandthemeasurementofitsabsorption.

The NO2 PDT harmonisation working grouprecommended speci ic protocols regardingmany of theabove issues 2 . For example, absorbent preparationshould be done either by dipping grids in 50:50TEA:acetone solution or by pipetting 50 L of 20:80TEA:watersolutionontothegrids.Some effects of temperature and relative humidity onPDTperformancehavebeennotedbut thesehavebeenvariable and within the general uncertainties in PDTmeasurements.

The twomajor lingeringbiasconcerns forPDTsare thepositivebiases fromwithin‐tubechemicalproductionofadditionalNO2andtheeffectofairmovementacrossthemouthof the tube causing a shortening of thediffusionpathcomparedwiththephysicallengthofthetube.The magnitude of the former bias depends on therelative amounts of NO,NO2, andO3 in the ambient airandwillbegreatestwhenNOandO3concentrationsarebothcomparabletoNO2concentrations.Thismeansthatthe effect is likely to be most signi icant in urbanbackground areas, and not at road sides, where O3concentrationstendtobelow,norinruralareas,wheremostNOxisalreadyintheformofNO2.Averagepositivebiasesof theorderof10 to20%havebeen reported for PDT exposures in urban backgroundair. The wind‐induced bias will clearly be highlydependent on the nature of the deployment site and ofthe windiness during a given exposure. The use ofsheltersoverthePDToracoarsemeshacrossthe“open”endofthetubeduringexposuremaybeabletomitigateagainst this positive bias, although further research onthisparticularissueisnecessary.The EU Directive on air quality 5 recognises theuncertainties in NO2 passive samplers and designatesthem as indicative measures of NO2 with a potentialuncertainty of 30%. Overall, however, with carefulpreparation and analysis, coupledwith an appreciationofissuesofpotentiallimitation,NO2PDTsremainaveryusefulmethodforunderstandingspatialandlonger‐termtrendsinambientNO2concentrations.

References

1.E.D.Palmes,A.F.Gunnison,J.DiMattio,C.Tomczyk,AmericanIndustrialHygieneAssociationJournal ,37,570 1976 .2.Defra2008,DiffusiontubesforambientNO2monitoring:practicalguidanceforlaboratoriesandusers.AreportbytheDefraWorkingGrouponHarmonisationofDiffusionTubeMethods,availableatwww.airquality.co.uk/archive/reports/cat05/0802141004_NO2_WG_PracticalGuidance_Issue1a.pdf.3.J.N.Cape,CriticalReviewsinAnalyticalChemistry,39,289 2009 .4.M. R. Heal, M. A. O’Donoghue, J. N. Cape,AtmosphericEnvironment,33,513 1999 .5.EU Directive on Air Quality, see http://ec.europa.eu/environment/air/quality/legislation/directive.htm.