Pakaonekwa mazinga akakwira eiyo trace element molybdenum (mah-LIB-den-um) mumatsime emvura yekunwa kumaodzanyemba kwakadziva kumabvazuva kweWisconsin, nzvimbo zhinji dzekurasira marasha emarasha munzvimbo iyi dzakaita sedzinogona kukonzera kusvibiswa uku.

Asi rimwe basa rekuferefeta rakakwenenzverwa rinotungamirwa nevatsvagiri veDuke University neThe Ohio State University rakaburitsa kuti madziva, ayo ane masara emarasha akapiswa mumagetsi, handiwo anokonzera kusvibiswa.

Inobva mumanyuko echisikigo panzvimbo pezvo.

"Zvichienderana nemiedzo inoshandisa forensic isotopic 'fingerprinting' uye nzira dzekufambidzana, mhedzisiro yedu inopa humbowo hwakazvimiririra hwekuti marasha emarasha haakonzere kusvibiswa mumvura," akadaro Avner Vengosh, purofesa we geochemistry uye mhando yemvura paDuke's Nicholas School of. Environment.

"Dai mvura ine molybdenum iyi yakabva mukunyurutswa kwedota remarasha, ingadai iri diki, yakachairwazve muaquifer yemvura yepasi kubva mumadota emarasha makore makumi maviri kana makumi matatu apfuura," akadaro Vengosh. "Panzvimbo iyoyo, bvunzo dzedu dzinoratidza kuti dzinobva pakadzika pasi pevhu uye ine makore anopfuura mazana matatu."

Miedzo iyi yakaratidzawo kuti mvura yakasvibiswa isotopic zvigunwe - iyo chaiyo ratios ye boron uye strontium isotopes - haina kuenderana neisotopic zvigunwe zvekusara kwemarasha.

Izvi zvakawanikwa "de-link" iyo molybdenum kubva kunzvimbo dzekurasa marasha uye panzvimbo pezvo zvinoti ndiwo mhedzisiro yemaitiro echisikigo anoitika muaquifer's rock matrix, akadaro Jennifer S. Harkness, muongorori wepashure kuOhio State uyo akatungamira chidzidzo ichi sechikamu. nezve dissertation yake yehudoctor paDuke.

Vatsvagiri vakaburitsa bepa ravo rakatariswa nevezera mwedzi uno mujenari Environmental Science & Technology.

Zvishoma zve molybdenum zvakakosha kuhupenyu hwemhuka nezvirimwa, asi vanhu vanoinwa zvakanyanya vanoisa njodzi yezvinetso zvinosanganisira kupererwa neropa, kurwadziwa kwemajoini uye kudedera.

Mamwe ematsime akaedzwa kumaodzanyemba kwakadziva kumabvazuva kweWisconsin aisvika 149 micrograms emolybdenum parita, zvishoma kudarika zvakapetwa kaviri chiyero chekunwa chakachengeteka cheWorld Health Organisation, chinova 70 micrograms parita. Iyo US Environmental Protection Agency inoisa muganho kunyange wakaderera pamakumi mana micrograms parita.

Kuitisa chidzidzo chitsva ichi, Harkness nevamwe vake vakashandisa forensic tracers kuona mareshiyo eboron kune strontium isotopes mune imwe neimwe yemasampuli emvura. Vakayerawo sampuli yega yega tritium nehelium radioactive isotopes, idzo dzine mwero wekuora nguva dzose uye dzinogona kushandiswa kuongorora zera remuenzaniso, kana “nguva yekugara” mumvura yepasi. Nekubatanidza aya maviri seti ezvakawanikwa, masayendisiti akakwanisa kubatanidza ruzivo rwakadzama nezvenhoroondo yemvura yepasi, kusanganisira payakatanga kupinda muaquifer, uye kuti ndeapi marudzi ematombo aakange asangana nawo nekufamba kwenguva.

“Ongororo iyi yakaratidza kuti mvura yakakwira-molybdenum haina kubva mumadota emarasha pamusoro, asi kuti yakabva kumaminerari ane molybdenum ari muaquifer matrix uye mamiriro ezvakatipoteredza mumvura yakadzika yaibvumira kuburitswa kwemolybdenum iyi mumvura. mvura yepasi,” Harkness akatsanangura kudaro.

"Chii chakasiyana nezvechirongwa ichi chekutsvagisa ndechekuti inobatanidza nzira mbiri dzakasiyana-isotopic zvigunwe zvemunwe uye zera-kufambidzana-muchidzidzo chimwe," akadaro.

Kunyangwe chidzidzo ichi chakanangana nematsime emvura yekunwa muWisconsin, zvakawanikwa zvinogona kushanda kune mamwe matunhu ane geologies akafanana.

Thomas H. Darrah, mubatsiri wepurofesa wesayenzi yepasi paOhio State, ndiye Harkness's postdoctoral advisor kuOhio State uye akanga ari munyori pamwe chete wechidzidzo chitsva.