Lokacin da aka gano manyan matakan molybdenum (mah-LIB-den-um) a cikin rijiyoyin ruwan sha a kudu maso gabashin Wisconsin, wuraren zubar da tokar kwal da yawa a yankin da alama sun kasance tushen gurbatar yanayi.

Amma wasu kyawawan ayyukan bincike da masu bincike daga Jami’ar Duke da Jami’ar Jihar Ohio suka jagoranta sun bayyana cewa tafkunan da ke dauke da ragowar gawayi da aka kona a masana’antar samar da wutar lantarki ba su ne tushen gurbatar yanayi ba.

Ya samo asali ne daga tushen halitta maimakon.

Avner Vengosh, farfesa a fannin ilimin kimiyyar halittu da ingancin ruwa a Makarantar Duke's Nicholas ya ce "Bisa gwaje-gwajen da aka yi amfani da su ta hanyar amfani da fasahar 'hantsa' na zamani da dabarun zamani, sakamakonmu yana ba da shaida mai zaman kanta cewa tokar kwal ba ita ce tushen gurɓata ruwa ba." Muhalli.

"Idan da wannan ruwa mai arzikin molybdenum ya fito ne daga tokawar kwal, da zai kasance matashi ne, bayan an sake caje shi a cikin magudanar ruwa na yankin daga tokar kwal a saman shekaru 20 ko 30 kacal da suka wuce," in ji Vengosh. "Maimakon haka, gwaje-gwajenmu sun nuna cewa ya fito ne daga zurfin karkashin kasa kuma yana da shekaru sama da 300."

Gwaje-gwajen kuma sun nuna cewa gurɓataccen yatsa na isotopic na ruwa—daidaitaccen rabonsa na boron da strontium isotopes—bai dace da hotunan yatsun isotopic na ragowar konewar kwal ba.

Wadannan binciken "de-link" molybdenum daga wuraren zubar da toka na kwal kuma a maimakon haka suna nuna cewa sakamakon tsarin halitta ne da ke faruwa a cikin matrix na dutsen ruwa, in ji Jennifer S. Harkness, wani mai bincike na postdoctoral a Jihar Ohio wanda ya jagoranci binciken a matsayin wani ɓangare. na digirinta na digiri a Duke.

Masu binciken sun buga takarda da takwarorinsu suka yi nazari a wannan watan a cikin mujallar Muhalli da Fasaha.

Ƙananan molybdenum suna da mahimmanci ga rayuwar dabba da tsire-tsire, amma mutanen da suka ci shi da yawa suna fuskantar hadarin matsalolin da suka hada da anemia, ciwon haɗin gwiwa da rawar jiki.

Wasu daga cikin rijiyoyin da aka gwada a kudu maso gabashin Wisconsin sun kunshi har zuwa 149 microgram na molybdenum kowace lita, dan kadan fiye da sau biyu ma'aunin ingancin ruwan sha na Hukumar Lafiya ta Duniya, wanda shine microgram 70 a kowace lita. Hukumar Kare Muhalli ta Amurka ta kafa iyaka har ma da ƙasa da 40 micrograms kowace lita.

Don gudanar da sabon binciken, Harkness da abokan aikinta sun yi amfani da na'urorin bincike don tantance ma'auni na boron zuwa strontium isotopes a cikin kowane samfurin ruwa. Sun kuma auna kowane samfurin tritium da helium isotopes na rediyoaktif, waɗanda ke da adadin ruɓe akai-akai kuma ana iya amfani da su don kimanta shekarun samfurin, ko “lokacin zama” a cikin ruwan ƙasa. Ta hanyar haɗa waɗannan nau'ikan binciken guda biyu, masanan sun sami damar tattara cikakkun bayanai game da tarihin ruwa na ƙasa, ciki har da lokacin da ya fara kutsawa cikin ruwa, da kuma nau'ikan duwatsun da ya yi mu'amala da su tsawon lokaci.

"Wannan bincike ya nuna cewa ruwa mai girma-molybdenum bai samo asali daga tarin toka na kwal a saman ba, amma ya samo asali ne daga ma'adanai masu arzikin molybdenum a cikin matrix aquifer da yanayin muhalli a cikin ruwa mai zurfi wanda ya ba da damar sakin wannan molybdenum a cikin ruwan karkashin kasa,” Harkness ya bayyana.

"Abin da ke da mahimmanci game da wannan aikin bincike shi ne cewa yana haɗa hanyoyin biyu daban-daban - hotunan yatsa na isotopic da kwanan wata - a cikin binciken daya," in ji ta.

Kodayake binciken ya mayar da hankali kan rijiyoyin ruwan sha a Wisconsin, bincikensa na iya yin amfani da shi ga sauran yankuna masu irin wannan yanayin.

Thomas H. Darrah, mataimakin farfesa a kimiyyar duniya a jihar Ohio, shine mai ba da shawara na karatun digiri na Harkness a jihar Ohio kuma shi ne marubucin sabon binciken.