{"id":3846,"date":"2017-10-01T04:30:12","date_gmt":"2017-10-01T04:30:12","guid":{"rendered":"https:\/\/himinnoghaf.is\/mengunsjavar\/?p=3846"},"modified":"2024-10-21T21:42:12","modified_gmt":"2024-10-21T21:42:12","slug":"5-5-astand-sjavar-vid-island","status":"publish","type":"post","link":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/2017\/10\/01\/5-5-astand-sjavar-vid-island\/","title":{"rendered":"5.5 Efnamengun \u00ed sj\u00f3num vi\u00f0 \u00cdsland"},"content":{"rendered":"

Sj\u00e1var\u00fatvegur er ein helsta uppspretta \u00fej\u00f3\u00f0arau\u00f0s okkar \u00cdslendinga. \u00dev\u00ed er afskaplega mikilv\u00e6gt fyrir okkur a\u00f0 vi\u00f0halda hreinleika sj\u00e1var \u00ed l\u00f6gs\u00f6gunni og fylgjast vel me\u00f0 \u00e1standi hafsins \u00ed kringum landi\u00f0 me\u00f0 tilliti til mengunarefna. G\u00f3\u00f0ar ni\u00f0urst\u00f6\u00f0ur geta enn fremur n\u00fdst \u00ed marka\u00f0ssetningu. \u00cd stefnum\u00f3tun<\/span><\/span>\u00a0\u00edslenskra stj\u00f3rnvalda sem l\u00fdtur a\u00f0 m\u00e1lefnum hafsins kemur \u00e6t\u00ed\u00f0 fram a\u00f0 \u00cdsland skuli vera \u00fe\u00e1tttakandi \u00ed al\u00fej\u00f3\u00f0legu samstarfi sem sn\u00fdr a\u00f0 verndun hafsins, vera lei\u00f0andi \u00e1 \u00feessu m\u00e1lefnasvi\u00f0i og \u00f6\u00f0rum \u00fej\u00f3\u00f0um fyrirmynd \u00ed umgengni vi\u00f0 hafi\u00f0.<\/p>\n

\u00cdsland er a\u00f0ili a\u00f0 OSPAR-samningnum (sj\u00e1 n\u00e1nar kafla 8.3.2<\/a>) og skal \u00ed samr\u00e6mi vi\u00f0 \u00e1kv\u00e6\u00f0i samningsins safna uppl\u00fdsingum um uppruna, dreifingu, styrk og \u00e1hrif efna sem geta veri\u00f0 ska\u00f0leg \u00ed umhverfi sj\u00e1var. Umhverfisstofnun<\/span> heldur utan um v\u00f6ktun \u00ed umhverfi sj\u00e1var og birtir ni\u00f0urst\u00f6\u00f0ur \u00e1 vefs\u00ed\u00f0u stofnunarinnar. G\u00f6gnunum er ennfremur skila\u00f0 \u00ed gagnagrunn Al\u00fej\u00f3\u00f0ahafranns\u00f3knar\u00e1\u00f0sins, ICES<\/span>.<\/span><\/p>\n

Fylgst hefur veri\u00f0 me\u00f0 styrk \u00fer\u00e1virkra l\u00edfr\u00e6nna efna<\/strong> og \u00feungm\u00e1lma<\/strong> \u00ed \u00feorski \u00e1 \u00cdslandsmi\u00f0um fr\u00e1 \u00e1rinu 1990. M\u00e6ldur hefur veri\u00f0 styrkur PCB<\/span>, HCB<\/span> og DDE<\/span><\/span>\u00a0\u00ed \u00feorsklifur en eiturefnin safnast fyrir \u00ed lifur og \u00fev\u00ed m\u00e6list h\u00e6stur styrkur \u00feeirra oftast \u00fear. Uppruna \u00fer\u00e1virkra l\u00edfr\u00e6nna efna \u00e1 \u00edslenska hafsv\u00e6\u00f0inu m\u00e1 b\u00e6\u00f0i rekja til uppsprettna \u00e1 \u00cdslandi og til a\u00f0fluttrar mengunar me\u00f0 haf- og loftstraumum. Eins og sj\u00e1 m\u00e1 \u00e1 mynd 5.10 hefur styrkur \u00feessara \u00fer\u00e1virku l\u00edfr\u00e6nu efna \u00ed \u00feorsklifur dregist nokku\u00f0 saman s\u00ed\u00f0ustu \u00e1r og \u00e1ratugi \u00ed kj\u00f6lfar banns vi\u00f0 notkun \u00feeirra um allan heim. Dregi\u00f0 hefur talsvert \u00far losun PCB og HCB \u00ed andr\u00famsloft<\/span>\u00a0<\/span>h\u00e9rlendis s\u00ed\u00f0ustu \u00e1r. HCB var nota\u00f0 \u00ed litlum m\u00e6li sem sveppaeitur en framlei\u00f0sla og notkun efnisins \u00ed \u00feeim tilgangi hefur veri\u00f0 b\u00f6nnu\u00f0 s\u00ed\u00f0an \u00e1 \u00e1ttunda \u00e1ratug 20. aldar. HCB getur einnig myndast vi\u00f0 bruna, svo sem vi\u00f0 brennslu \u00fargangs og jar\u00f0eldsneytis. Helstu uppsprettur losunar HCB \u00ed andr\u00famsloft h\u00e9rlendis er brennsla \u00e1 \u00fargangi fr\u00e1 sj\u00fakrastofnunum, notkun flugelda, \u00e1lframlei\u00f0sla og brennsla ol\u00edu um bor\u00f0 \u00ed fiskiskipum. Losun HCB \u00ed andr\u00famsloft hefur sem fyrr segir dregist talsvert saman s\u00ed\u00f0ustu \u00e1r en eftirlit me\u00f0 magni \u00feess \u00ed flugeldum var hert verulega eftir a\u00f0 m\u00e6lingar s\u00fdndu fram \u00e1 mikinn styrk \u00ed flugeldum fr\u00e1 tilteknum framlei\u00f0endum. Helstu uppsprettur losunar PCB \u00ed andr\u00famsloft h\u00e9r \u00e1 landi eru brennsla \u00fargangs og brennsla ol\u00edu um bor\u00f0 \u00ed skipum. Mun meiri losun PCB-efna \u00e1 s\u00e9r sta\u00f0 \u00feegar svartol\u00edu er brennt um bor\u00f0 \u00ed skipum, en \u00feegar um gasol\u00edu er a\u00f0 r\u00e6\u00f0a. Miki\u00f0 hefur dregi\u00f0 \u00far losun PCB \u00ed andr\u00famsloft h\u00e9rlendis fr\u00e1 1990. Kemur \u00fear einkum tvennt til: lokun sementsverksmi\u00f0junnar \u00e1 Akranesi \u00e1ri\u00f0 2012 og b\u00e6tt me\u00f0h\u00f6ndlun \u00fargangs, en opin brennsla \u00fargangs dr\u00f3st saman h\u00e9rlendis \u00e1 \u00feessum \u00e1rum og lag\u00f0ist loks af \u00e1ri\u00f0 2004. Engar \u00feekktar uppsprettur \u00e1 DDE er a\u00f0 finna h\u00e9rlendis eftir a\u00f0 notkun DDT var h\u00e6tt. Efni\u00f0 finnst hins vegar enn \u00ed umhverfinu vegna \u00feess hve \u00fer\u00e1virkt \u00fea\u00f0 er.<\/p>\n

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Mat\u00eds m\u00e6ldi sex PCB-efni og d\u00edox\u00edn \u00ed holdi nokkurra fisktegunda (m.a. \u00ed \u00feorski, \u00fdsu, ufsa, s\u00edld og makr\u00edl) sem og \u00ed \u00feorsklifur h\u00e9r vi\u00f0 land \u00e1ri\u00f0 <\/span>2022<\/span>. Styrkur PCB reyndist <\/span>langt<\/span> undir vi\u00f0mi\u00f0unarm\u00f6rkum sem eru 75 \u00b5g\/kg af votvigt \u00ed fiskholdi en 200 \u00b5g\/kg af votvigt fyrir lifur. Ni\u00f0urst\u00f6\u00f0urnar voru mj\u00f6g svipa\u00f0ar fyrir d\u00edox\u00edn \u2013 flest gildi voru n\u00e1l\u00e6gt 0,3 ng\/kg<\/span>\u00a0<\/span>af votvigt \u00ed fiskholdi en leyfilegur h\u00e1marksstyrkur er 3,5 ng\/kg.<\/p>\n

Uppruna \u00feungm\u00e1lma \u00e1 \u00edslenska hafsv\u00e6\u00f0inu m\u00e1 b\u00e6\u00f0i rekja til uppsprettna \u00e1 \u00cdslandi en einnig til \u00a0mengunar sem berst hinga\u00f0 me\u00f0 haf- og loftstraumum. Styrkur \u00feungm\u00e1lma \u00ed fiski hefur veri\u00f0 m\u00e6ldur fr\u00e1 \u00e1rinu 1990 og \u00e1 mynd 5.10 m\u00e1 sj\u00e1 styrk kadm\u00edums (Cd) \u00ed \u00feorsklifur og kvikasilfurs (Hg) \u00ed \u00feorskholdi fr\u00e1 \u00feessum t\u00edma. M\u00e6lingar \u00e1 styrk \u00feungm\u00e1lma \u00ed \u00feorski h\u00e9r vi\u00f0 land benda til n\u00e1tt\u00farulegs uppruna og ekki er a\u00f0 sj\u00e1 sk\u00fdra leitni \u00ed m\u00e6lingunum. Styrkur \u00feungm\u00e1lma \u00ed l\u00edfr\u00edki h\u00e9r vi\u00f0 land er l\u00e6gri e\u00f0a svipa\u00f0ur og \u00e1 \u00f6\u00f0rum samb\u00e6rilegum hafsv\u00e6\u00f0um. Undantekning er \u00fe\u00f3 kadm\u00edum sem m\u00e6list \u00ed h\u00e6rri styrk \u00ed \u00feorsklifur h\u00e9r vi\u00f0 land en \u00e1 samb\u00e6rilegum hafsv\u00e6\u00f0um, t.d. vi\u00f0 Noreg. Uppspretta kadm\u00edums er talin vera af n\u00e1tt\u00farulegum toga (hugsanlega tengt sta\u00f0bundnu rofi n\u00e1l\u00e6gt Nor\u00f0ur-Atlantshafshryggnum e\u00f0a eldsumbrotum) \u00fear sem engin teljandi mannger\u00f0 uppspretta kadm\u00edum er \u00feekkt h\u00e9r vi\u00f0 land.<\/p>\n

Mat\u00eds m\u00e6ldi m.a. bl\u00fd (Pb), kadm\u00edum (Cd) og kvikasilfur (Hg) \u00ed holdi nokkurra matfisktegunda (m.a. \u00ed \u00feorski, \u00fdsu, ufsa, s\u00edld og makr\u00edl) sem og \u00ed \u00feorsklifur h\u00e9r vi\u00f0 land \u00e1ri\u00f0 <\/span>2022<\/span>. Styrkur m\u00e1lmanna reyndist langt undir h\u00e1marksstyrk mengunarefna \u00ed matv\u00e6lum.\u00a0<\/span><\/p>\n

\u00deungm\u00e1lmar og \u00fer\u00e1virk l\u00edfr\u00e6n efni hafa veri\u00f0 m\u00e6ld \u00ed kr\u00e6klingi \u00e1 nokkrum st\u00f6\u00f0um \u00ed kringum landi\u00f0 fr\u00e1 2003 ef fr\u00e1 eru skilin \u00e1rin 2013-2017. \u00c1rlega eru fimmt\u00edu kr\u00e6klingar teknir \u00e1 hverjum sta\u00f0 og \u00feeir sameina\u00f0ir \u00ed eitt s\u00fdni. \u00c1 mynd 5.11 m\u00e1 sj\u00e1 sta\u00f0setningu s\u00fdnat\u00f6kusta\u00f0a<\/span> <\/span>og me\u00f0alstyrk \u00feungm\u00e1lma (arsens, kadm\u00edum, kvikasilfurs) og \u00fer\u00e1virkra l\u00edfr\u00e6nna efna (DDE, HCB, HCH, PCB, trans-nonochlor) \u00ed kr\u00e6klingnum. \u00c1hugavert er a\u00f0 sko\u00f0a muninn \u00e1 styrk efnanna eftir landshlutum. Styrkur kadm\u00edum m\u00e6list nokku\u00f0 h\u00e1r vi\u00f0 Nor\u00f0ur- og Austurland. Talsver\u00f0 arsenmengun greindist vi\u00f0 \u00dalfs\u00e1 skammt fr\u00e1 \u00cdsafir\u00f0i en ekki hefur tekist a\u00f0 sk\u00fdra uppruna \u00feess. Ef mengunin hef\u00f0i tengst sorpbrennslu \u00ed Funa \u00e1 \u00cdsafir\u00f0i, \u00fe\u00e1 hef\u00f0u \u00f6nnur efni sem tengjast brennslu (t.d. HCB) a\u00f0 m\u00e6last l\u00edka h\u00e1, en \u00fea\u00f0 var ekki tilfelli\u00f0. Styrkur \u00fer\u00e1virkra l\u00edfr\u00e6nna efna \u00ed kr\u00e6klingi er h\u00e6stur \u00ed Hvalfir\u00f0i.<\/p>\n

\"\"<\/a>

Mynd 5.11. Styrkur \u00fer\u00e1virkra l\u00edfr\u00e6nna efna og \u00feungm\u00e1lma \u00ed kr\u00e6klingi \u00e1 s\u00fdnat\u00f6kust\u00f6\u00f0um um landi\u00f0.<\/p><\/div>\n

A\u00f0gengileg n\u00e6ringarefni<\/strong> berast \u00e1 \u00edslenska hafsv\u00e6\u00f0i\u00f0 og leggja grunninn a\u00f0 frj\u00f3semi \u00feess, sem stendur m.a. undir fiskvei\u00f0um \u00fej\u00f3\u00f0arinnar. Sem fyrr segir getur ofgn\u00f3tt n\u00e6ringarefna valdi\u00f0 ofau\u00f0gun \u00fear sem vatnsskipti eru \u00f3n\u00f3g (sj\u00e1 kafla 5.2). Styrkur n\u00e6ringarefna (n\u00edtrats og fosfats) hefur veri\u00f0 vakta\u00f0ur \u00ed Faxafl\u00f3a fr\u00e1 \u00e1rinu 2005 \u00e1 n\u00edu st\u00f6\u00f0vum sem n\u00e1 fr\u00e1 Akranesi og \u00fat yfir landgrunnsbr\u00fan. Styrkur n\u00e6ringarefna \u00ed sj\u00f3 er breytilegur eftir \u00e1rst\u00edma og \u00fev\u00ed fer v\u00f6ktun fram um h\u00e1vetur \u00feegar styrkurinn er \u00ed \u00e1rlegu h\u00e1marki og \u00e1hrif l\u00edfr\u00edkisins hva\u00f0 minnst. Ni\u00f0urst\u00f6\u00f0ur m\u00e6linganna benda ekki til mengunar af v\u00f6ldum n\u00e6ringarefna. Vatnsskipti vi\u00f0 strendur landsins eru yfirleitt hr\u00f6\u00f0 og losun n\u00e6ringarefna \u00fev\u00ed ekki l\u00edkleg til a\u00f0 valda h\u00e6ttu \u00e1 ofau\u00f0gun. H\u00e9r vi\u00f0 land eru f\u00e1ar st\u00f3rar uppsprettur n\u00e6ringarefna og sj\u00e1varstraumar oftast sterkir. Ekki eru \u00feekkt d\u00e6mi um n\u00e6ringarefnaofau\u00f0gun \u00ed sj\u00f3num h\u00e9r vi\u00f0 land. \u00de\u00f3 \u00fearf a\u00f0 fylgjast vel me\u00f0 sta\u00f0bundnum \u00e1hrifum \u00fear sem miki\u00f0 magn n\u00e6ringarefna er losa\u00f0 \u00fat \u00ed umhverfi\u00f0 (t.d. \u00ed n\u00e1grenni sl\u00e1turh\u00fasa og fiskeldis) \u00fear sem vatnsskipti eru hugsanlega \u00f3n\u00f3g.<\/p>\n

Fiskeldi h\u00e9rlendis hefur vaxi\u00f0 hratt s\u00ed\u00f0ustu \u00e1r. \u00c1ri\u00f0 2023 voru framleidd r\u00famlega 40.000 tonn \u00a0\u00ed sj\u00f3kv\u00edum og hefur framlei\u00f0sla vaxi\u00f0 verulega fr\u00e1 \u00e1rinu 2015 \u00feegar h\u00fan var 3.500 tonn. Langmest er framleitt af laxi. \u00cd laxeldi \u00ed sj\u00f3 eru notu\u00f0 um 1,0-1,5 kg af f\u00f3\u00f0ri \u00e1 hvert kg af laxi. Nokkur hluti f\u00f3\u00f0ursins fer til spillis og fl\u00fdtur anna\u00f0 hvort burt me\u00f0 straumum e\u00f0a sekkur til botns. Eitthva\u00f0 af \u00fev\u00ed n\u00fdtist hugsanlega \u00f6\u00f0rum d\u00fdrum en st\u00e6rstur hluti fellur til botns og rotnar, \u00e1samt \u00fargangi fr\u00e1 l\u00f6xunum sj\u00e1lfum. \u00cd rotnunarferlinu myndast kold\u00edox\u00ed\u00f0 og\/e\u00f0a metan, eftir \u00fev\u00ed a\u00f0 hve miklu leyti s\u00farefni kemst a\u00f0 efninu, en \u00fea\u00f0 r\u00e6\u00f0st v\u00e6ntanlega b\u00e6\u00f0i af d\u00fdpi og straumum sem og af magni l\u00edfr\u00e6nna \u00fargangsefna og s\u00far\"\"<\/a>efnisa\u00f0st\u00e6\u00f0um vi\u00f0 botninn. Ef a\u00f0st\u00e6\u00f0ur ver\u00f0a loftfirr\u00f0ar myndast \u00ed einhverjum m\u00e6li brennisteinsvetni (H2<\/sub>S) og ammon\u00edaki (NH3<\/sub>). \u00deessi efni eru eitru\u00f0 fyrir laxa og \u00fev\u00ed myndi uppstreymi \u00feeirra undir sj\u00f3kv\u00edum lei\u00f0a til verulegra vanhalda \u00ed kv\u00edunum. Af \u00feessum s\u00f6kum eru kv\u00edarnar stundum fluttar til. Nokku\u00f0 er nota\u00f0 af eiturefnum \u00ed laxeldi. Stundum eru efni sem innihalda kopar notu\u00f0 til a\u00f0 varna \u00feess a\u00f0 gr\u00f3\u00f0ur taki s\u00e9r b\u00f3lfestu \u00e1 kv\u00edunum og netpokunum. S\u00ed\u00f0ustu \u00e1r hafa l\u00fasafaraldrar komi\u00f0 upp \u00ed laxeldi vi\u00f0 \u00cdslands strendur. Fram a\u00f0 \u00feeim t\u00edma haf\u00f0i veri\u00f0 tali\u00f0 a\u00f0 laxal\u00fasin g\u00e6ti ekki lifa\u00f0 \u00ed svo k\u00f6ldum sj\u00f3. Til a\u00f0 breg\u00f0ast vi\u00f0 l\u00fasinni hefur notkun eiturefna veri\u00f0 leyf\u00f0. Eiturefnin geta dreifst um fir\u00f0ina og valdi\u00f0 \u00f6\u00f0ru l\u00edfr\u00edki ska\u00f0a.<\/div>\n

<\/p>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Sj\u00e1var\u00fatvegur er ein helsta uppspretta \u00fej\u00f3\u00f0arau\u00f0s okkar \u00cdslendinga. \u00dev\u00ed er afskaplega mikilv\u00e6gt fyrir okkur a\u00f0 vi\u00f0halda hreinleika sj\u00e1var \u00ed l\u00f6gs\u00f6gunni og fylgjast vel me\u00f0 \u00e1standi hafsins \u00ed kringum landi\u00f0 me\u00f0 tilliti til mengunarefna. G\u00f3\u00f0ar ni\u00f0urst\u00f6\u00f0ur geta enn fremur n\u00fdst \u00ed Lesa meira…<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[25],"tags":[],"class_list":["post-3846","post","type-post","status-publish","format-standard","hentry","category-5-efnamengun"],"_links":{"self":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/3846","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/comments?post=3846"}],"version-history":[{"count":29,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/3846\/revisions"}],"predecessor-version":[{"id":4037,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/3846\/revisions\/4037"}],"wp:attachment":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/media?parent=3846"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/categories?post=3846"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/tags?post=3846"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}