Haɗuwa

Imposex cuta ce da aka lura a wasu nau'ikan gastropod na ruwa mai laushi, inda mata ke haɓaka halaye na jima'i na namiji, kamar azzakari da vas deferens, saboda fallasawa ga takamaiman gurɓataccen muhalli. Wannan yanayin ya samo asali ne daga mahaɗan organotin, musamman tributyltin (TBT), waɗanda aka yi amfani da su sosai a cikin antifouling paints don jiragen ruwa don hana biofouling. Ba kamar yanayin Intersex wanda ya shafi gonadal ambiguity ba, imposex yana haifar da superimposition na namiji a kan aikin Haɗuwa na mace, sau da yawa yana haifar da rashin haihuwa da raguwar yawan jama'a a cikin nau'in da abin ya shafa.

An fara rubuta wannan sabon abu a cikin shekarun 1960 kuma tun daga lokacin an gano shi a cikin nau'ikan gastropod sama da 260 a duk duniya. Imposex yana aiki ne a matsayin mai nuna alamar rayuwa mai mahimmanci don saka idanu kan gurɓataccen organotin a cikin yanayin ruwa. Sau da yawa ana ƙididdige tsananin imposex ta amfani da Vas Deferens Sequence Index (VDSI), wanda ke kimanta ci gaban gabobin namiji a cikin mata.

Dangane da haɗarin muhalli da TBT ta kawo, an aiwatar da ƙa'idodin ƙasa da ƙasa don ƙuntata amfani da shi. Ƙungiyar Maritime ta Duniya (IMO) ta amince da haramtacciyar haramtacciya ta duniya kan allunan rigakafin TBT, wanda ya fara aiki a cikin 2008. Bincike na gaba ya nuna raguwar yaduwar jima'i a wasu yankuna, yana nuna raguwar farfadowar yawan gastropod da abin ya shafa. Koyaya, ci gaba da TBT a cikin ruwan teku yana ci gaba da haifar da ƙalubale don kawar da tasirin jima'i.

 Tarihi 
A cikin shekarun 1950, an gano mahadi na organotin suna da tasiri sosai wajen hana gina kwayoyin ruwa a kan jirgin ruwa, wanda ya haifar da yaduwar amfani da su a cikin fentin antifouling a cikin shekarun 1960.  Amfani da waɗannan fentin ya fadada cikin sauri a cikin wannan shekaru goma. A ƙarshen shekarun 1960, masu bincike sun fara lura da imposex a cikin dogwhelk na yau da kullun, Nucella lapillus .  An kuma lura da shi shekaru 10 bayan haka a cikin wani nau'in, Ilyanassa obsoleta,  amma har zuwa 1981 ne wannan abin da ya faru ya danganta kai tsaye da bayyanar organotin.  Da zarar an haɗa, matsin lamba ya hau don kawar da tributyltin (TBT) da kuma organotins masu alaƙa daga samfuran rigakafin ruwa saboda tasirin muhalli.

Kodayake yawancin bincike kan imposex a tarihi sun mayar da hankali kan nau'in ruwa, gurɓataccen organotin da imposex ba a ƙuntata su ga wuraren zama na ruwa kawai ba. An san yanayin da ya shafi nau'in estuarine kamar Heleobia australis,  da kuma nau'in ruwa mai laushi kamar ƙwayoyin apple (Pomacea spp.),  da kuma ƙwayoyin Apple (Marisa cornuarietis).

 Tasirin halittu 
Imposex a cikin gastropods na ruwa yana haifar da mahadi na organotin da ke tsoma baki tare da tsarin hormonal na ci gaban jima'i. Kodayake wannan haɗin ya kafu sosai, masana kimiyya har yanzu ba su yarda da ainihin hanyoyin halittu da ke ciki ba.Schøyen, Merete; Green, Norman W.; Hjermann, Dag Ø.; Tveiten, Lise; Beylich, Bjørnar; Øxnevad, Sigurd; Beyer, Jonny (2019). "Levels and trends of tributyltin (TBT) and imposex in dogwhelk (Nucella lapillus) along the Norwegian coastline from 1991 to 2017". Marine Environmental Research. 144: 1–8. Bibcode:2019MarER.144....1S. doi:10.1016/j.marenvres.2018.11.011. hdl:11250/2622076. PMID 30497665. Yawancin ra'ayoyin da ke fafatawa sun ba da shawarar cewa organotins suna rushe hanyoyi daban-daban na siginar hormonal, gami da tsarin neuroendocrine, Steroid-like, ko retinoid (vitamin A-related). Hakanan yana yiwuwa cewa hanyoyi da yawa suna ba da gudummawa ga yanayin, kodayake ba a tabbatar da wannan ba.

A cikin nau'o'in kamar dog whelk, ci gaban azzakari a cikin mata masu jima'i a hankali yana toshe Oviduct, kodayake samar da ovule yana ci gaba. kwai kare mai tsayi yana wucewa ta matakai da yawa na girma na azzakari kafin ya kasa kula da samar da ƙwai a kai a kai. Matakan baya na imposex yana haifar da rashin haihuwa da mutuwar mata masu shekaru na haihuwa, wanda zai iya shafar dukkan jama'a.

Duk da rashin tabbas game da ainihin hanyoyin, binciken da aka yi a shekara ta 2006 ya gano imposex a matsayin daya daga cikin 'yan kalilan da za a iya dogara da su don tantance haɗarin muhalli da saka idanu kan lafiyar muhalli. Wannan ya faru ne saboda babban hankali, takamaimansa ga bayyanar organotin, da kuma yanayin da aka fahimta sosai na tasirin kwayoyin halitta. Bugu da ƙari, ba a sauƙaƙa tasirin imposex ta hanyar rikice-rikice na muhalli ba, kuma yanayin da ke cikin ƙwayoyin ƙwayoyin cuta na iya haɗawa kai tsaye da tasiri mai yawa akan yawan jama'a da ƙarfin al'ummaSchøyen, Merete; Green, Norman W.; Hjermann, Dag Ø.; Tveiten, Lise; Beylich, Bjørnar; Øxnevad, Sigurd; Beyer, Jonny (2019). "Levels and trends of tributyltin (TBT) and imposex in dogwhelk (Nucella lapillus) along the Norwegian coastline from 1991 to 2017". Marine Environmental Research. 144: 1–8. Bibcode:2019MarER.144....1S. doi:10.1016/j.marenvres.2018.11.011. hdl:11250/2622076. PMID 30497665.

 Manazarta 
Rukuni:Shafuka masu fassarorin da ba'a duba ba