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<\/a>\n\u00davod<\/h2>\n
Star\u00e1 \u0159\u00ed\u010dn\u00ed ramena tvo\u0159\u00ed velmi v\u00fdznamn\u00e9 ekosyst\u00e9my. Nejen \u017ee mohou b\u00fdt domovem vz\u00e1cn\u00fdch a\u00a0chr\u00e1n\u011bn\u00fdch druh\u016f, ale zvy\u0161uj\u00ed reten\u010dn\u00ed potenci\u00e1l krajiny, tak\u017ee hraj\u00ed velmi d\u016fle\u017eitou roli v\u00a0protipovod\u0148ov\u00e9 ochran\u011b. Krom\u011b jejich ekologick\u00e9ho v\u00fdznamu p\u0159edstavuj\u00ed zdroj informac\u00ed o\u00a0historick\u00e9m zne\u010di\u0161t\u011bn\u00ed, kter\u00e9 se v\u00a0povod\u00ed Labe od 2. poloviny 20. stolet\u00ed s\u00a0rozvojem pr\u016fmyslu v\u00fdznamn\u011b zv\u00fd\u0161ilo. Od roku 1900 bylo Labe intenzivn\u011b regulov\u00e1no a\u00a0tak\u00e9 vystavov\u00e1no zhor\u0161uj\u00edc\u00ed se kvalit\u011b \u017eivotn\u00edho prost\u0159ed\u00ed kv\u016fli nadu\u017e\u00edv\u00e1n\u00ed hnojiv, nedostate\u010dn\u00e9mu \u010di\u0161t\u011bn\u00ed odpadn\u00edch vod apod. \u0158eka je dlouhodob\u011b vystavena zne\u010di\u0161\u0165ov\u00e1n\u00ed ze zem\u011bd\u011blstv\u00ed, jeliko\u017e prot\u00e9k\u00e1 intenzivn\u011b zem\u011bd\u011blsky vyu\u017e\u00edvanou oblast\u00ed s\u00a0p\u011bstov\u00e1n\u00edm obil\u00ed, zeleniny a\u00a0dal\u0161\u00edch plodin a\u00a0pr\u016fmyslovou v\u00fdrobou v\u010detn\u011b komun\u00e1ln\u00edho zne\u010di\u0161t\u011bn\u00ed z\u00a0v\u00fdroby a\u00a0s\u00eddel soust\u0159ed\u011bn\u00fdch v\u00a0tomto regionu (Pardubice, Kol\u00edn, Neratovice). I\u00a0p\u0159esto se ve star\u00fdch \u0159\u00ed\u010dn\u00edch ramenech zachovaly funguj\u00edc\u00ed nivn\u00ed ekosyst\u00e9my [1].<\/p>\n
V\u00a0posledn\u00edch letech se kvalitou vody a\u00a0sediment\u016f v\u00a0jezerech v\u00a0t\u00e9to oblasti zab\u00fdvali v\u011bde\u010dt\u00ed pracovn\u00edci Univerzity Karlovy [1\u20133], kte\u0159\u00ed se zam\u011b\u0159ili mimo jin\u00e9 i\u00a0na v\u00fdzkum kvality vody ve fluvi\u00e1ln\u00edm jeze\u0159e Vr\u0165. Zm\u00edn\u011bn\u00e9 studie zahrnovaly vybran\u00e9 oblasti labsk\u00e9 nivy a\u00a0mnoho fluvi\u00e1ln\u00edch jezer z\u016fstalo st\u00e1le nezmapov\u00e1no. Jedn\u00edm z\u00a0nich je Kozelsk\u00e1 t\u016f\u0148. Toto jezero bylo pro tuto studii vybr\u00e1no kv\u016fli poloze u\u00a0Spolany Neratovice, a. s., kter\u00e1 v\u00a0minulosti p\u0159edstavovala jeden z\u00a0nejv\u011bt\u0161\u00edch zdroj\u016f zne\u010di\u0161t\u011bn\u00ed Labe.<\/p>\n
Pr\u00e1ce se zam\u011b\u0159ila na pravideln\u00e9 ode\u010dty vodn\u00edch stav\u016f a\u00a0m\u011bs\u00ed\u010dn\u00ed anal\u00fdzy chemick\u00fdch a\u00a0fyzik\u00e1ln\u00edch parametr\u016f kvality vody. V\u00a0r\u00e1mci pr\u016fzkumn\u00fdch prac\u00ed se prov\u00e1d\u011bly zrnitostn\u00ed anal\u00fdzy a\u00a0stanoven\u00ed koncentrac\u00ed kov\u016f a\u00a0arsenu v\u00a0sedimentech.<\/p>\n
Studovan\u00e9 lokality<\/h2>\nKozelsk\u00e1 t\u016f\u0148<\/h3>\n
Kozelsk\u00e1 t\u016f\u0148 se nach\u00e1z\u00ed na prav\u00e9m b\u0159ehu \u0159eky Labe mezi 851,9 a\u00a0851,1 \u0159\u00ed\u010dn\u00edm\u00a0km bl\u00edzko obce Ml\u00e9kojedy, kter\u00e1 le\u017e\u00ed v\u00a0okrese Neratovice. Toto fluvi\u00e1ln\u00ed jezero je spojeno s\u00a0\u0159ekou \u00fazk\u00fdmi kan\u00e1ly na 851,9 a\u00a0850,1 \u0159\u00ed\u010dn\u00edm km. Podlo\u017e\u00ed lokality tvo\u0159\u00ed hlinito-p\u00eds\u010dit\u00e9 sedimenty.<\/p>\n
Ve druh\u00e9 polovin\u011b 20. stolet\u00ed bylo zamrzl\u00e9 jezero v\u00e1pn\u011bno a\u00a0tak\u00e9 prob\u011bhlo vybagrov\u00e1n\u00ed sediment\u016f ze dna jezera. Severov\u00fdchod jezera je obklopen ornou p\u016fdou a\u00a0pastvami. V\u00a0jihov\u00fdchodn\u00ed \u010d\u00e1sti se nach\u00e1z\u00ed les, na severu od jezera se nach\u00e1z\u00ed chatov\u00e1 kolonie, kter\u00e1 m\u016f\u017ee p\u0159edstavovat lok\u00e1ln\u00ed zdroj zne\u010di\u0161t\u011bn\u00ed z\u00a0jejich dom\u00e1cnost\u00ed, p\u011bstov\u00e1n\u00ed plodin a\u00a0vypou\u0161t\u011bn\u00ed vody z\u00a0baz\u00e9n\u016f.<\/p>\n
Obr\u00e1zek 1<\/em> zn\u00e1zor\u0148uje v\u00fdvoj jezera. Jak je vid\u011bt na map\u011b z\u00a0III. vojensk\u00e9ho mapov\u00e1n\u00ed, v\u00a0roce 1852 byl meandr je\u0161t\u011b st\u00e1le sou\u010d\u00e1st\u00ed \u0159eky. Meandr byl pravd\u011bpodobn\u011b odstaven na za\u010d\u00e1tku 20. stolet\u00ed. Prav\u00e1 \u010d\u00e1st obr. 1<\/em> zobrazuje sou\u010dasn\u00fd stav jezera, kdy je z\u0159ejm\u00e9, \u017ee tok byl nap\u0159\u00edmen a\u00a0meandr je s\u00a0\u0159ekou spojen pouze \u00fazk\u00fdmi kan\u00e1ly.<\/p>\n Jezero Vr\u0165 se nach\u00e1z\u00ed na lev\u00e9m b\u0159ehu \u0159eky Labe mezi 881,7 a\u00a0881,2 \u0159\u00ed\u010dn\u00edm km v\u00a0obci Semice, kter\u00e1 je situov\u00e1na v\u00a0okrese Nymburk. Jezero je spojeno s\u00a0Labem jen \u00fazk\u00fdm kan\u00e1lem na 881,2 \u0159\u00ed\u010dn\u00edm km pod jezerem ve sm\u011bru toku Labe. Podlo\u017e\u00ed lokality tvo\u0159\u00ed pleistocenn\u00ed fluvi\u00e1ln\u00ed sedimenty a\u00a0p\u00eds\u010dit\u00fdmi \u0161t\u011brky [6]. Ve druh\u00e9 polovin\u011b 20. stolet\u00ed bylo jezero v\u00e1pn\u011bno [3]. Obr\u00e1zek 2<\/em> zobrazuje propojen\u00ed meandru s\u00a0\u0159ekou v\u00a0roce 1852. Jezero bylo odstaveno od Labe pravd\u011bpodobn\u011b ve 40. letech 20. stolet\u00ed. V\u00a050. letech bylo kompletn\u011b odstaveno bez povrchov\u00e9 komunikace s\u00a0\u0159ekou. K\u00a0op\u011btovn\u00e9mu spojen\u00ed do\u0161lo a\u017e v\u00a090. letech 20.\u00a0stolet\u00ed. Aktu\u00e1ln\u00ed stav je zobrazen v\u00a0prav\u00e9 \u010d\u00e1sti obr. 2<\/em>, kdy je jezero s\u00a0\u0159ekou propojeno kan\u00e1lem.<\/p>\n M\u011b\u0159en\u00ed fyzik\u00e1ln\u011b-chemick\u00fdch parametr\u016f povrchov\u00e9 vody v\u00a0Kozelsk\u00e9 t\u016fni prob\u011bhlo ve dvou r\u016fzn\u00fdch \u010d\u00e1stech jezera (obr. 3<\/em>). V\u00fdsledn\u00e1 hodnota jednotliv\u00fdch m\u011bs\u00ed\u010dn\u00edch koncentrac\u00ed byla spo\u010d\u00edt\u00e1na jako pr\u016fm\u011br z\u00a0t\u011bchto dvou hodnot. V\u00a0jeze\u0159e Vr\u0165 prob\u00edhalo vzorkov\u00e1n\u00ed povrchov\u00e9 vody z\u00a0jednoho odb\u011brov\u00e9ho m\u00edsta. M\u011b\u0159en\u00ed prob\u011bhlo 9\u00d7 za rok. V\u00a0ter\u00e9nu byla multiparametrickou sondou HQ40D Hach-Lange m\u011b\u0159ena teplota vody, rozpu\u0161t\u011bn\u00fd kysl\u00edk ve vod\u011b, pH a\u00a0vodivost. P\u0159esnost sondy p\u0159i m\u011b\u0159en\u00ed koncentrace rozpu\u0161t\u011bn\u00e9ho kysl\u00edku ve vod\u011b je \u00b11\u00a0%, u\u00a0m\u011b\u0159en\u00ed konduktivity 0,5\u00a0% a\u00a0u\u00a0teploty 0,3\u00a0%.<\/p>\n Povrchov\u00e1 voda byla odebr\u00e1na z\u00a0hloubky 10\u2008cm pod hladinou, ze vzd\u00e1lenosti cca 1\u2008m od b\u0159ehu. Dal\u0161\u00ed stanovovan\u00e9 parametry jako chemick\u00e1 spot\u0159eba kysl\u00edku (CHSKMn<\/sub>), biochemick\u00e1 spot\u0159eba kysl\u00edku (BSK5<\/sub>), N-NH4<\/sub>, N-NO2<\/sub>, N-NO3<\/sub>, P-PO4<\/sub>, Cl, alkalita, Ca, Fe, Mn a\u00a0tvrdost vody byly m\u011b\u0159eny v\u00a0laborato\u0159i \u00dastavu pro \u017eivotn\u00ed prost\u0159ed\u00ed na Univerzit\u011b Karlov\u011b. Vzorky povrchov\u00e9 vody byly odebr\u00e1ny mezi 10 h a\u00a014 h a\u00a0dopraveny v\u00a0chladic\u00edm boxu do laborato\u0159e do 16 h stejn\u00e9ho dne. Tabulka 1<\/em> zn\u00e1zor\u0148uje seznam pou\u017eit\u00fdch laboratorn\u00edch metod.<\/p>\n J\u00e1dra dnov\u00fdch sediment\u016f byla odebr\u00e1na p\u00edstov\u00fdm odb\u011br\u00e1kem Eijkelkamp ze \u010dlunu z\u00a0m\u00edsta cca 3\u2008m od b\u0159ehu a\u00a0byla rozd\u011blena do vrstev po 10\u2008cm, kter\u00e9 pak byly analyzov\u00e1ny odd\u011blen\u011b. Jednotliv\u00e9 vzorky byly uchov\u00e1ny ve vzduchot\u011bsn\u00fdch s\u00e1\u010dc\u00edch v\u00a0chladic\u00edm boxu. D\u00e9lka odebran\u00fdch jader sediment\u016f \u010dinila 59\u2008cm. V\u00a0ka\u017ed\u00e9m jeze\u0159e byl proveden jeden odb\u011br (obr. 4<\/em>). Z\u00a0Kozelsk\u00e9 t\u016fn\u011b byl sediment odebr\u00e1n t\u00e9m\u011b\u0159 u\u00a0konce v\u00fdchodn\u00ed \u010d\u00e1sti ramene, jeliko\u017e v\u00a0ostatn\u00edch\u00a0m\u00edstech jezera nebyly pro odb\u011br vhodn\u00e9 zrnitostn\u00ed podm\u00ednky (p\u0159\u00edli\u0161 hrub\u00fd materi\u00e1l). Z\u00a0jezera Vr\u0165 byl odb\u011br sediment\u016f \u00fasp\u011b\u0161n\u011b proveden zhruba uprost\u0159ed d\u00e9lky jezera.<\/p>\n V\u00a0sedimentech byly stanoveny koncentrace Ag, Al, As, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Zn a\u00a0Ti v\u017edy z\u00a0reprezentativn\u00edho vzorku ze zhomogenizovan\u00e9 10\u2008cm siln\u00e9 vrstvy. Homogenizace byla provedena v\u00a0t\u0159ec\u00ed misce za mokra, po rozdru\u017een\u00ed byla odebr\u00e1na \u010d\u00e1st vzorku na odd\u011blen\u00ed frakce 20 \u00b5m. Tato zrnitostn\u00ed frakce byla zvolena z\u00a0d\u016fvodu srovnatelnosti s\u00a0dal\u0161\u00edmi v\u00fdzkumy labsk\u00fdch sediment\u016f. Produkt s\u00edtov\u00e1n\u00ed byl n\u00e1sledn\u011b usu\u0161en p\u0159i laboratorn\u00ed teplot\u011b na vzduchu na Petriho misk\u00e1ch. Pro chemickou anal\u00fdzu bylo takto z\u00edsk\u00e1no cca 5 gram\u016f vzorku.<\/p>\n Koncentrace kov\u016f a\u00a0arsenu v\u00a0sedimentech byly stanoveny ve v\u00fdluhu lu\u010davkou kr\u00e1lovskou. Nav\u00e1\u017eka vzorku 0,5\u2008g byla zalita 10\u2008ml lu\u010davky kr\u00e1lovsk\u00e9 (2,5\u2008ml HNO3<\/sub> + 7,5\u2008ml HCl) do tlakov\u00fdch n\u00e1dobek Savilex, kter\u00e9 p\u0159es noc st\u00e1ly uzav\u0159en\u00e9 p\u0159i laboratorn\u00ed teplot\u011b. Pot\u00e9 byly zah\u0159\u00edv\u00e1ny 6\u00a0hodin p\u0159i teplot\u011b 105\u2008\u00b0C, po vychladnut\u00ed byl roztok p\u0159eveden do objemu 50\u2008ml. K\u00a0m\u011b\u0159en\u00ed pomoc\u00ed emisn\u00ed spektrometrie s\u00a0induk\u010dn\u011b v\u00e1zan\u00fdm plazmatem (ICP OES) bylo pou\u017eito \u0159ed\u011bn\u00ed 10\u00d7 a\u00a0100\u00d7.<\/p>\n Obsah rtuti byl stanoven atomov\u00fdm absorp\u010dn\u00edm spektrometrem AMA-254 z\u00a0pevn\u00fdch vzork\u016f. V\u00fdsledky hodnocen\u00ed m\u00edry kontaminace sediment\u016f jsou pops\u00e1ny v\u00a0kapitole 4.2.<\/p>\n Hodnoty pH povrchov\u00e9 vody v\u00a0jeze\u0159e Vr\u0165 i\u00a0Kozelsk\u00e9 t\u016fni p\u0159edstavovaly neutr\u00e1ln\u00ed nebo slab\u011b alkalick\u00e9 prost\u0159ed\u00ed (tabulka 2<\/em>). M\u00edrn\u00e9 zv\u00fd\u0161en\u00ed pH bylo zji\u0161t\u011bno na konci zimy a\u00a0na za\u010d\u00e1tku jara, co\u017e bylo pravd\u011bpodobn\u011b zp\u016fsobeno zv\u00fd\u0161enou \u010dinnost\u00ed fytoplanktonu, p\u0159i kter\u00e9 byl z\u00a0vody od\u010derp\u00e1v\u00e1n CO2<\/sub>.<\/p>\n Zejm\u00e9na v\u00a0jeze\u0159e Vr\u0165 byly nam\u011b\u0159eny vysok\u00e9 hodnoty konduktivity b\u011bhem zimn\u00edch a\u00a0jarn\u00edch m\u011bs\u00edc\u016f, co\u017e mohlo korespondovat s\u00a0vy\u0161\u0161\u00edmi koncentracemi Ca, Cl (obr. 6<\/em>) a\u00a0N-NO3<\/sub>. Ke zv\u00fd\u0161en\u00ed konduktivity mohly p\u0159isp\u011bt splachy l\u00e1tek z\u00a0pol\u00ed a\u00a0posypu silnic b\u011bhem t\u00e1n\u00ed sn\u011bhu nebo v\u00e1pn\u011bn\u00ed jezer. Vy\u0161\u0161\u00ed koncentrace chlorid\u016f a\u00a0fosfore\u010dnanov\u00e9ho fosforu m\u016f\u017eou tak\u00e9 indikovat zne\u010di\u0161t\u011bn\u00ed odpadn\u00edmi vodami [7]. Hodnoty konduktivity v\u00a0Kozelsk\u00e9 t\u016fni byly nejpodobn\u011bj\u0161\u00ed hodnot\u00e1m nam\u011b\u0159en\u00fdm v\u00a0jeze\u0159e Ob\u0159\u00edstv\u00ed (tabulka 3<\/em>).<\/p>\n V\u00a0Kozelsk\u00e9 t\u016fni byl v\u00a0l\u00e9t\u011b pozorov\u00e1n vy\u0161\u0161\u00ed obsah rozpu\u0161t\u011bn\u00e9ho kysl\u00edku ve vod\u011b (obr. 5<\/em>), co\u017e mohlo b\u00fdt v\u00fdsledkem vysok\u00e9 populace fytoplanktonu v\u00a0jeze\u0159e. V\u00a0jeze\u0159e Vr\u0165 byl zaznamen\u00e1n ni\u017e\u0161\u00ed obsah kysl\u00edku od dubna do z\u00e1\u0159\u00ed 2017, co\u017e pravd\u011bpodobn\u011b korespondovalo s\u00a0vy\u0161\u0161\u00edmi teplotami vody, kdy je rozpustnost kysl\u00edku ni\u017e\u0161\u00ed a\u00a0zvy\u0161uje se intenzita rozkladn\u00fdch proces\u016f, kdy je kysl\u00edk spot\u0159ebov\u00e1v\u00e1n. Ni\u017e\u0161\u00ed koncentrace kysl\u00edku byly tak\u00e9 zaznamen\u00e1ny\u00a0v\u00a0obdob\u00ed \u201eclear water\u201c po \u00fapadku fytoplanktonu, kter\u00fd byl doprov\u00e1zen vysok\u00fdmi koncentracemi fosfore\u010dnanov\u00e9ho fosforu ve vod\u011b [6]. Podobn\u00fd trend koncentrac\u00ed kysl\u00edku nam\u011b\u0159en\u00fdch v\u00a0jezeru Vr\u0165 byl pozorov\u00e1n tak\u00e9 v\u00a0jezeru N\u011bm\u010dice (tabulka 3<\/em>).<\/p>\n Kozelsk\u00e1 t\u016f\u0148 i\u00a0jezero Vr\u0165 vykazovaly vysok\u00e9 koncentrace N-NH4<\/sub>. V\u00a0obou jezerech byl v\u00a0b\u0159eznu, dubnu a\u00a0srpnu vy\u010derp\u00e1n P-PO4<\/sub> (obr. 6<\/em>) kv\u016fli vysok\u00e9 produktivit\u011b fytoplanktonu. Naopak vysok\u00e9 koncentrace P-PO4<\/sub> byly zaznamen\u00e1ny b\u011bhem obdob\u00ed \u201eclear water\u201c, kdy n\u00edzk\u00fd obsah rozpu\u0161t\u011bn\u00e9ho kysl\u00edku ve vod\u011b umo\u017enil uvoln\u011bn\u00ed P ze sediment\u016f po redukci \u017eeleza v\u00a0molekule FePO4<\/sub> [8]. Vy\u0161\u0161\u00ed obsah P byl tak\u00e9 nam\u011b\u0159en v\u00a0zim\u011b a\u00a0na konci vegeta\u010dn\u00edho obdob\u00ed, k\u00a0\u010demu\u017e mohlo p\u0159isp\u011bt sm\u00fdv\u00e1n\u00ed hnojiv z\u00a0p\u0159ilehl\u00fdch pol\u00ed nebo jin\u00e9 antropogenn\u00ed zne\u010di\u0161t\u011bn\u00ed \u010di dotace z\u00a0obohacen\u00e9 podzemn\u00ed vody.<\/p>\n V\u00a0obou jezerech byly nam\u011b\u0159eny vysok\u00e9 hodnoty CHSKMn<\/sub> b\u011bhem vegeta\u010dn\u00edho obdob\u00ed p\u0159i zv\u00fd\u0161en\u00ed biochemick\u00fdch a\u00a0rozkladn\u00fdch proces\u016f za vy\u0161\u0161\u00ed teploty.<\/p>\n V\u00a0r\u00e1mci klasifikace \u010cSN 757\u00a0221 [9] byla povrchov\u00e1 voda za\u0159azena do kategorie \u201esiln\u011b zne\u010di\u0161t\u011bn\u00e1\u201c (IV. t\u0159\u00edda) v\u00a0p\u0159\u00edpad\u011b parametru BSK5 <\/sub>v\u00a0Kozelsk\u00e9 t\u016fni (tabulka<\/em>\u00a01<\/em>). Do kategorie \u201ezne\u010di\u0161t\u011bn\u00e9 vody\u201c (III. t\u0159\u00edda) byla kvalita povrchov\u00e9 vody za\u0159azena v\u00a0p\u0159\u00edpad\u011b parametr\u016f BSK5<\/sub> v\u00a0jeze\u0159e Vr\u0165, CHSKMn<\/sub> v\u00a0obou jezerech a\u00a0u\u00a0N-NH4<\/sub> v\u00a0jeze\u0159e Vr\u0165 (tabulka 2<\/em>).<\/p>\n Ni\u017e\u0161\u00ed koncentrace t\u00e9m\u011b\u0159 v\u0161ech m\u011b\u0159en\u00fdch prvk\u016f byly zaznamen\u00e1ny ve vzorc\u00edch z\u00a0jezera Vr\u0165, kter\u00e1 byla od 50. do 90. let odd\u011blena od Labe, a\u00a0proto zde nedoch\u00e1zelo v\u00a0takov\u00e9 m\u00ed\u0159e k\u00a0sedimentaci kontaminovan\u00e9ho materi\u00e1lu. V\u00a0tomto \u00faseku Labe se rovn\u011b\u017e nenach\u00e1z\u00ed v\u00fdznamn\u00fd zdroj zne\u010di\u0161t\u011bn\u00ed, jako je tomu nap\u0159. v\u00a0oblasti Neratovic nebo Pardubic (Synthesia, a. s.). Vy\u0161\u0161\u00ed obsahy stanovovan\u00fdch l\u00e1tek v\u00a0Kozelsk\u00e9 t\u016fni pravd\u011bpodobn\u011b souvisely s\u00a0jej\u00ed polohou v\u00a0bl\u00edzkosti Spolany\u00a0Neratovice, a.\u00a0s., a\u00a0jej\u00edmu celkov\u00e9mu um\u00edst\u011bn\u00ed v\u00a0niv\u011b a\u00a0spojen\u00ed s\u00a0Labem, kdy za povodn\u00ed doch\u00e1z\u00ed k\u00a0zalit\u00ed cel\u00e9 oblasti. V\u00a0roce 2002 bylo rovn\u011b\u017e zaznamen\u00e1no vzdut\u00ed proti proudu Labe z\u00a0rozvodn\u011bn\u00e9 Vltavy, jej\u00ed\u017e soutok nele\u017e\u00ed daleko\u00a0[13]. P\u0159i takov\u00fdch hydrologick\u00fdch situac\u00edch doch\u00e1z\u00ed k\u00a0resuspendaci jemn\u00e9 frakce sediment\u016f, kter\u00e1 m\u016f\u017ee obsahovat zna\u010dn\u00e9 mno\u017estv\u00ed \u0161kodlivin, a\u00a0tak se mohla kontaminace roz\u0161\u00ed\u0159it do \u0161ir\u0161\u00ed oblasti nivy.<\/p>\n Tabulka 4<\/em> zn\u00e1zor\u0148uje pr\u016fm\u011brn\u00e9 koncentrace m\u011b\u0159en\u00fdch prvk\u016f v\u00a0j\u00e1drech sediment\u016f zkouman\u00fdch jezer ve srovn\u00e1n\u00ed s\u00a0v\u00fdsledky star\u0161\u00edch v\u00fdzkum\u016f proveden\u00fdch v\u00a0dal\u0161\u00edch ramenech ve St\u0159edn\u00edm Polab\u00ed. Barevn\u00e9 rozli\u0161en\u00ed odpov\u00edd\u00e1 za\u0159azen\u00ed do kategorie m\u00edry zne\u010di\u0161t\u011bn\u00ed sediment\u016f pomoc\u00ed Geoakumula\u010dn\u00edho indexu, jak definuje [14] za pou\u017eit\u00ed poza\u010fov\u00fdch koncentrac\u00ed stanoven\u00fdch [15].<\/p>\n Cn<\/sub> = koncentrace nam\u011b\u0159en\u00e1 ve vzorku<\/p>\n Bn<\/sub> = poza\u010fov\u00e1 koncentrace m\u011b\u0159en\u00e9ho prvku<\/p>\n T\u0159\u00eddy kontaminace v\u010detn\u011b limitn\u00edch hodnot Geoakumula\u010dn\u00edho indexu uv\u00e1d\u00ed tabulka 5<\/em>.<\/p>\n Lze konstatovat, \u017ee podle pou\u017eit\u00e9 klasifikace vykazovaly sedimenty ve srovn\u00e1van\u00fdch labsk\u00fdch star\u00fdch ramenech vysokou z\u00e1t\u011b\u017e st\u0159\u00edbrem a\u00a0kadmiem. Vy\u0161\u0161\u00ed kontaminace sediment\u016f byla zji\u0161t\u011bna p\u0159edev\u0161\u00edm v\u00a0lokalit\u00e1ch u\u00a0v\u00fdznamn\u00fdch pr\u016fmyslov\u00fdch zdroj\u016f zne\u010di\u0161t\u011bn\u00ed a\u00a0s\u00a0intenzivn\u011bj\u0161\u00ed komunikac\u00ed s\u00a0\u0159ekou, co\u017e by odpov\u00eddalo vy\u0161\u0161\u00edm obsah\u016fm kov\u016f v\u00a0Kozelsk\u00e9 t\u016fni, kter\u00e1 se nach\u00e1z\u00ed bl\u00edzko Spolany Neratovice, a. s., a je spojena kan\u00e1ly s\u00a0Labem a\u00a0p\u0159i povodn\u00edch zde doch\u00e1z\u00ed k\u00a0zalit\u00ed \u0161ir\u0161\u00ed nivy v\u010detn\u011b zkouman\u00e9 lokality.<\/p>\n Kontaminace z\u00a0bodov\u00e9ho zne\u010di\u0161t\u011bn\u00ed se od roku 1990 v\u00fdznamn\u011b sn\u00ed\u017eila, ale plo\u0161n\u00e9 zdroje zne\u010di\u0161t\u011bn\u00ed, nap\u0159. z\u00a0orn\u00e9 p\u016fdy, p\u0159edstavuj\u00ed st\u00e1le probl\u00e9m [16]. D\u00edky tomu vykazuj\u00ed star\u00e1 ramena \u010dasto vy\u0161\u0161\u00ed koncentrace N-NO3<\/sub>. V\u00a0Kozelsk\u00e9 t\u016fni i\u00a0v\u00a0jeze\u0159e Vr\u0165 byly ve vod\u011b nam\u011b\u0159eny rovn\u011b\u017e nejvy\u0161\u0161\u00ed koncentrace N-NH4 <\/sub>ve srovn\u00e1n\u00ed s\u00a0n\u011bkter\u00fdmi porovn\u00e1van\u00fdmi star\u00fdmi rameny St\u0159edn\u00edho Polab\u00ed.<\/p>\n Z\u00a0hlediska zat\u00ed\u017een\u00ed sediment\u016f lze konstatovat, \u017ee v\u011bt\u0161ina star\u00fdch labsk\u00fdch ramen vykazovala vy\u0161\u0161\u00ed zat\u00ed\u017een\u00ed sediment\u016f st\u0159\u00edbrem a\u00a0kadmiem. V\u00a0n\u011bkter\u00fdch jezerech, nap\u0159. v\u00a0Kozelsk\u00e9 t\u016fni, byl tak\u00e9 nam\u011b\u0159en vysok\u00fd obsah rtuti a\u00a0olova. V\u00a0Kozelsk\u00e9 t\u016fni byly krom\u011b t\u011bchto prvk\u016f nam\u011b\u0159eny vy\u0161\u0161\u00ed koncentrace i\u00a0arsenu a\u00a0zinku. Podobn\u00e1 m\u00edra kontaminace byla zaznamen\u00e1na i\u00a0v\u00a0dal\u0161\u00edch lokalit\u00e1ch s\u00a0v\u00fdjimkou star\u00fdch ramen N\u011bm\u010dice \u010di Doleh\u00e1j, co\u017e by bylo mo\u017en\u00e9 vysv\u011btlit\u00a0jejich v\u00fdrazn\u011b omezenou komunikac\u00ed s\u00a0\u0159ekou, kter\u00e1 zamezila ukl\u00e1d\u00e1n\u00ed kontaminovan\u00e9 suspenze, nebo se jezera nach\u00e1zela nad pr\u016fmyslov\u00fdmi zdroji zne\u010di\u0161t\u011bn\u00ed, jako tomu bylo v\u00a0p\u0159\u00edpad\u011b star\u00e9ho ramene N\u011bm\u010dice [1].<\/p>\n Zne\u010di\u0161t\u011bn\u00ed v\u00a0Kozelsk\u00e9 t\u016fni mohlo b\u00fdt zp\u016fsobeno transportem kontaminovan\u00e9ho materi\u00e1lu p\u0159i povodn\u00edch z\u00a0oblasti u\u00a0Spolany Neratovice, a. s., i\u00a0p\u0159es to, \u017ee jezero le\u017e\u00ed cca 2\u2008km proti proudu od t\u00e9to chemick\u00e9 tov\u00e1rny. Tato hypot\u00e9za je zalo\u017eena na faktech z\u00a0povodn\u00ed, kdy byla cel\u00e1 oblast zaplaven\u00e1. \u201eV\u00a0pr\u016fb\u011bhu druh\u00e9 f\u00e1ze srpnov\u00e9 povodn\u011b Vltava zp\u016fsobila ve zna\u010dn\u00e9 d\u00e9lce zp\u011btn\u00e9 vzdut\u00ed hladiny a\u00a0po ur\u010ditou dobu dokonce zp\u011btn\u00e9 proud\u011bn\u00ed v\u00a0trati Labe sm\u011brem k\u00a0Brand\u00fdsu nad Labem. Chemick\u00fd podnik Spolana Neratovice na b\u0159ehu Labe byl zaplaven pr\u00e1v\u011b zp\u011btn\u00fdm vzdut\u00edm Vltavy\u201c [13].<\/p>\n Dal\u0161\u00edm v\u00fdznamn\u00fdm faktorem byla v\u00fdznamnost a\u00a0vzd\u00e1lenost od pr\u016fmyslov\u00e9ho zdroje zne\u010di\u0161t\u011bn\u00ed. Takto lze vysv\u011btlit nap\u0159. ni\u017e\u0161\u00ed m\u00edru kontaminace v\u00a0jeze\u0159e u\u00a0Pod\u011bbrad, nebo\u0165 a\u010dkoliv toto star\u00e9 rameno komunikuje intenzivn\u011b s\u00a0\u0159ekou, kol\u00ednsk\u00fd pr\u016fmysl pravd\u011bpodobn\u011b nedosahoval takov\u00e9ho v\u00fdznamu, jak tomu bylo nap\u0159. v\u00a0p\u0159\u00edpad\u011b Synthesie, a. s., v\u00a0Pardubic\u00edch, nebo Spolany, a. s., v\u00a0Neratovic\u00edch. Kontaminace sediment\u016f star\u00fdch ramen poch\u00e1z\u00ed ze star\u00e9ho antropogenn\u00edho zne\u010di\u0161t\u011bn\u00ed, kter\u00e9 m\u016f\u017ee b\u00fdt remobilizov\u00e1no b\u011bhem povodn\u00ed. Za takov\u00fdch situac\u00ed mohou tyto star\u00e9 z\u00e1t\u011b\u017ee p\u0159edstavovat i\u00a0sekund\u00e1rn\u00ed zdroj zne\u010di\u0161t\u011bn\u00ed. Za ur\u010dit\u00fdch hydrologick\u00fdch podm\u00ednek nebo p\u0159i pr\u016fmyslov\u00fdch hav\u00e1ri\u00edch se m\u016f\u017ee zm\u011bnit pH nebo redoxn\u00ed potenci\u00e1l, kdy se stabiln\u00ed formy toxick\u00fdch prvk\u016f mohou st\u00e1t op\u011bt rozpustn\u00fdmi a\u00a0kontaminovat tak vodn\u00ed prost\u0159ed\u00ed. Tyto formy jsou snadn\u011bji vyu\u017e\u00edv\u00e1ny \u017eiv\u00fdmi organismy a\u00a0mohou se tak dostat do potravn\u00edho \u0159et\u011bzce. P\u0159i povodni mohou tyto toxick\u00e9 l\u00e1tky kontaminovat i\u00a0p\u0159ilehl\u00e9 zem\u011bd\u011blsk\u00e9 oblasti. Jak je tedy evidentn\u00ed, rizikovost kontaminovan\u00fdch sediment\u016f je velmi zna\u010dn\u00e1, a\u00a0proto je t\u0159eba se t\u00edmto v\u00fdzkumem p\u0159edev\u0161\u00edm v\u00a0hust\u011b obydlen\u00e9 a\u00a0zem\u011bd\u011blsky vyu\u017e\u00edvan\u00e9 oblasti labsk\u00e9 nivy detailn\u011b zab\u00fdvat.<\/p>\n \u00a0<\/em><\/p>\n P\u016fvodn\u00ed p\u0159\u00edsp\u011bvek byl publikov\u00e1n ve sborn\u00edku Rybn\u00edky 2018, ISBN 978-80-01-06452-8.<\/p>\n","protected":false},"excerpt":{"rendered":" Tato pr\u00e1ce je zam\u011b\u0159ena na zhodnocen\u00ed kvality vody a antropogenn\u00edho zne\u010di\u0161t\u011bn\u00ed sediment\u016f ve star\u00fdch ramenech Kozelsk\u00e1 t\u016f\u0148 a Vr\u0165 st\u0159edn\u00edho toku Labe. Star\u00e1 \u0159\u00ed\u010dn\u00ed ramena jsou v\u00fdznamn\u00fdmi ekosyst\u00e9my, ve kter\u00fdch se m\u016f\u017ee ukl\u00e1dat velk\u00e9 mno\u017estv\u00ed zne\u010di\u0161t\u011bn\u00e9ho materi\u00e1lu. Tato kontaminace m\u016f\u017ee poch\u00e1zet z pr\u016fmyslov\u00fdch zdroj\u016f zne\u010di\u0161t\u011bn\u00ed p\u0159edev\u0161\u00edm z 2. pol. 20. stolet\u00ed. <\/p>\n","protected":false},"author":8,"featured_media":5876,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[86,87],"tags":[1507,261,1509,1506,1505,1508],"coauthors":[1497,1498],"class_list":["post-5926","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hydraulics-hydrology-and-hydrogeology","category-hydrochemistry-radioecology-microbiology","tag-fluvialni-jezera","tag-kvalita-vody","tag-prumyslova-kontaminace","tag-reka-labe","tag-subaquaticke-sedimenty","tag-tezke-kovy"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/5926","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=5926"}],"version-history":[{"count":4,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/5926\/revisions"}],"predecessor-version":[{"id":30495,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/5926\/revisions\/30495"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/5876"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=5926"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=5926"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=5926"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=5926"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a>\nObr. 1. III. vojensk\u00e9 mapov\u00e1n\u00ed (vlevo [4]) a\u00a0sou\u010dasn\u00e9 ortofoto Kozelsk\u00e9 t\u016fn\u011b (vpravo [5]) 1 : 25 000
\nFig. 1. The III. Military survey (left [4]) and current aerial photograph (right [5]) of lake Kozelsk\u00e1, 1 : 25 000<\/h6>\nVr\u0165<\/h3>\n
<\/a>\nObr. 2. III. vojensk\u00e9 mapov\u00e1n\u00ed (vlevo [4] 1 : 25\u00a0000) a\u00a0aktu\u00e1ln\u00ed ortofoto jezera Vr\u0165 (vpravo\u00a0[5] 1 : 10\u00a0000)
\nFig. 2. The III. Military survey (left [4] 1 : 25\u00a0000) and current aerial photograph (right [5] 1\u00a0:\u00a010\u00a0000) of Vr\u0165 lake<\/h6>\nMetody<\/h2>\n
Fyzik\u00e1ln\u011b-chemick\u00e9 parametry povrchov\u00e9 vody<\/h3>\n
<\/a>\nObr. 3. Odb\u011brov\u00e1 m\u00edsta povrchov\u00e9 vody z\u00a0Kozelsk\u00e9 t\u016fn\u011b (vlevo) a\u00a0z\u00a0jezera Vr\u0165 (vpravo) [5]
\nFig. 3. Sampling sites of surface water in Vr\u0165 lake (V) and Kozelsk\u00e1 lake (K1, K2) [5]<\/h6>\nAnal\u00fdza sediment\u016f<\/h3>\n
<\/a>\nObr. 4. Odb\u011brov\u00e1 m\u00edsta sediment\u016f v\u00a0Kozelsk\u00e9 t\u016fni (vlevo) a\u00a0v\u00a0jeze\u0159e Vr\u0165 (vpravo) [5]
\nFig. 4. Sampling sites of sediments in Vr\u0165 lake (V) and Kozelsk\u00e1 lake (K) [5]<\/h6>\nTabulka 1. Pou\u017eit\u00e9 laboratorn\u00ed metody p\u0159i anal\u00fdze povrchov\u00e9 vody
\nTable 1. Laboratory methods of water quality determination<\/h5>\n<\/a>\nV\u00fdsledky a\u00a0diskuse<\/h2>\n
Kvalita povrchov\u00e9 vody<\/h3>\n
Tabulka 2. Nam\u011b\u0159en\u00e9 hodnoty parametr\u016f povrchov\u00e9 vody (ur\u010den\u00ed charakteristick\u00e9 hodnoty, k\u00a0jej\u00edmu\u017e nep\u0159ekro\u010den\u00ed dojde s\u00a090% pravd\u011bpodobnost\u00ed a\u00a0n\u00e1sledn\u00e9 za\u0159azen\u00ed do t\u0159\u00edd kvality vody bylo provedeno podle \u010cSN 75 7221 \u2013 Jakost vod)
\nTable 2. Concentrations of measured parameters in water (characteristic value was calculated with 90% probability; clasiffication to quality classes was made according to the Czech National Standard \u2013 Classification of Surface Water Quality (757\u00a0221))<\/h5>\n<\/a>\n<\/a>\nObr. 5. Koncentrace rozpu\u0161t\u011bn\u00e9ho O2<\/sub> ve vod\u011b v\u00a0jeze\u0159e Vr\u0165 (naho\u0159e) a\u00a0v\u00a0Kozelsk\u00e9 t\u016fni (dole)
\nFig. 5. Concentrations of O2<\/sub> dissolved in water in Vr\u0165 lake (above) and Kozelsk\u00e1 lake (down)<\/h6>\nTabulka 3. Srovn\u00e1n\u00ed fyzik\u00e1ln\u011b-chemick\u00fdch parametr\u016f povrchov\u00e9 vody s\u00a0dal\u0161\u00edmi fluvi\u00e1ln\u00edmi jezery St\u0159edn\u00edho Polab\u00ed [1, 3, 10\u201312] (v\u00a0mg\/l, v\u00a0p\u0159\u00edpad\u011b konduktivity v\u00a0ms\/m; uveden\u00fd rok odpov\u00edd\u00e1 dob\u011b, kdy prob\u00edhalo m\u011b\u0159en\u00ed v\u00a0dan\u00e9 lokalit\u011b)
\nTable 3. Comparison of chemical and physical parameters of surface water with the other oxbow lakes of the middle course of the Elbe River [1, 3, 10\u201312] (in mg\/l, in the case of conductivity in ms\/m; year corresponds to the time of measurement in each locality)<\/h5>\n<\/a>\nKvalita sediment\u016f<\/h3>\n
Tabulka 4. Pr\u016fm\u011brn\u00e9 koncentrace m\u011b\u0159en\u00fdch prvk\u016f v\u00a0sediment\u00e1rn\u00edch j\u00e1drech z\u00a0vybran\u00fdch star\u00fdch ramen St\u0159edn\u00edho Polab\u00ed [1, 10, 11] s\u00a0barevn\u00fdm rozli\u0161en\u00edm m\u00edry kontaminace podle indexu geoakumulace na z\u00e1klad\u011b poza\u010fov\u00fdch hodnot Turekiana a\u00a0Wedepohla (1961) (uveden\u00fd rok odpov\u00edd\u00e1 dob\u011b, kdy byl proveden odb\u011br sedimentu a\u00a0jeho anal\u00fdza)
\nTable 4. Mean concentrations of measured elements in sediment cores of selected oxbow lakes of the middle course of the Elbe River [1, 10, 11]; colors correspond to the rate of contamination according to Geoacumulation Index calculated from background values of Turekian and Wedepohl (1961); year corresponds to the time of sampling and its analyses<\/h5>\n<\/a>\n<\/a>\nZ\u00e1v\u011br<\/h2>\n
<\/a>\nObr. 6. Koncentrace Cl (naho\u0159e) a\u00a0P-PO4 <\/sub>(dole) v\u00a0jeze\u0159e Vr\u0165 a\u00a0Kozelsk\u00e9 t\u016fni
\nFig. 6. Concentrations of Cl (above) and P-PO4<\/sub> (down) in Vr\u0165 lake and Kozelsk\u00e1 lake<\/h6>\nTabulka 5. T\u0159\u00eddy kontaminace sediment\u016f podle Igeo [14]
\nTable 5. Igeo classes of sediment pollution [14]<\/h5>\n<\/a>\n