Gwajin Matsayin Farko na Rayuwa

Gwajin matakin farko (ELS) gwajin guba ne na yau da kullun ta amfani da matakan farko na rayuwa kamar embryos ko tsutsa don tsinkayar illar masu sa maye akan kwayoyin halitta.^[1] An haɓaka gwaje-gwajen ELS don zama mafi sauri kuma mafi inganci fiye da cikakkun gwaje-gwajen rayuwa, ɗaukar matsakaicin watanni 1-5 don kammalawa idan aka kwatanta da watanni 6-12 don gwajin sake zagayowar rayuwa. Ana amfani da su a cikin ilimin toxicology na ruwa, musamman tare da kifi. Ci gaba da rayuwa sune wuraren da aka auna na ƙarshe, waɗanda za a iya ƙididdige Maɗaukakin Maɗaukaki Mai Guba (MATC). Gwaje-gwajen ELS suna ba da damar gwada nau'in kifin waɗanda in ba haka ba ba za a iya yin nazari ba saboda tsawon rayuwa, buƙatun ƙirƙira, ko girma. Ana amfani da gwaje-gwajen ELS a matsayin wani ɓangare na kimanta haɗarin muhalli ta hanyar hukumomin da suka dace ciki har da Hukumar Kare Muhalli ta Amurka (EPA) da Muhalli Kanada, da kuma Ƙungiyar Haɗin Kan Tattalin Arziki da Ci Gaba (OECD).^[2]

Ci gaba

Gwaje-gwajen ELS an daidaita su daga cikakkun gwaje-gwaje masu guba na rayuwa, gwaje-gwaje na yau da kullun waɗanda ke fallasa kwayoyin halitta ga gurɓatacce don dukan tsarin rayuwarta. Ana ɗaukar waɗannan a matsayin mafi kyawun gwaje-gwaje don ƙididdige yawan "aminci" na dogon lokaci na masu sa maye a cikin halittun ruwa. Na farko cikakken gwajin sake zagayowar rayuwa akan kifin an haɓaka shi don fatshead minnow (Pimephales promelas),^[3] kuma daga baya don bluegill (Lepomis macrochirus), ruwan kifi (Salvelinus fontinalis), kifin (Jordanella floridae), da tumaki minnow (Cyprinodon variegatus). Yayinda yake da amfani, cikakkun gwaje-gwajen rayuwa suna buƙatar adadi mai yawa na kwayoyin gwaji da kuma tsawon lokacin bayyanarwa a cikin lab, musamman ga kashin baya. Yawanci, gwaje-gwajen zagayowar rayuwa suna ɗaukar watanni 6-12 don fatattakar fata da kuma watanni 30 don ƙwanƙwasa.

Bayan zartar da Dokar Kula da Abubuwan Guba (TSCA) a cikin Amurka a cikin 1976, an sami ƙarin buƙatu don saurin gwaje-gwaje masu guba na vertebrate. Yanzu ana buƙatar EPA don tantance tasirin muhalli na sabbin sinadarai kafin a iya samar da su ta kasuwanci. Ana buƙatar gwaje-gwaje marasa tsada kuma masu ɗaukar lokaci don kimanta ɗimbin sabbin sinadarai. Masu bincike sun fara haɓaka gwaje-gwaje masu guba waɗanda ke mayar da hankali kan matakan rayuwa na farko, tun da an nuna waɗannan sun fi dacewa da matsalolin muhalli fiye da matakan rayuwa na baya. Yawancin abubuwa masu mahimmanci suna faruwa a cikin ɗan gajeren lokaci a farkon matakan ci gaba.^[4] Idan mai damuwa ya rushe abubuwan ci gaba (ciki har da lokacinsu), zai iya haifar da mummunan tasiri wanda zai rage yiwuwar rayuwa. Meta-bincike ya gano cewa farkon lokacin rayuwa na cikakken gwajin zagayowar rayuwa yawanci ana kimanta MATC a cikin kashi 2 na cikakken kididdigar rayuwa a cikin ruwan gishiri da kifayen ruwa. A cikin 83% na gwaje-gwaje na 72, sashin ELS ya haifar da MATC guda ɗaya kamar cikakken ƙididdigar rayuwa, kuma sauran 17% sun kasance a cikin adadin 2.

Iyakance

Akwai sauran iyakoki tare da gwajin cutarwa na farkon rayuwa. Kodayake gwaje-gwajen ELS sun fi sauri da inganci fiye da cikakkun gwaje-gwajen sake zagayowar rayuwa, sun kasance masu amfani da lokaci. Gwajin farkon kifin (FELS) yana buƙatar ɗaruruwan kifi da watanni 1 zuwa 5 don kammalawa.[8] Sauran batutuwan sun haɗa da rashin bayanan injiniyoyi, bambancin ra'ayi tsakanin nau'in halitta, da rashin jin daɗin bayyanar iyaye. Gwaje-gwajen ELS ba su ba da bayani kan tsarin aikin mai guba ba. Hankali ga takamaiman abubuwan maye ya bambanta da nau'in nau'in, don haka ya kamata a gwada mafi mahimmanci ko mafi mahimmanci a kowane yanayi. Gwaje-gwajen ELS da alama ba su da hankali ga bayyanar iyaye, kuma MATCs gabaɗaya iri ɗaya ne ga embryo na duka fallasa da iyayen da ba a fallasa. Wannan na iya zama saboda yanayin aikin mai guba ko kuma sauye-sauye da rashin hankali na ƙirar gwajin ELS. Bugu da ƙari, an gano amsawar ci gaba a matsayin ƙarshen rashin jin daɗi a cikin gwaje-gwajen ELS tare da kifin, ba su da ɗan tasiri kan ƙima na MATC.^[5]

Manazarta

↑ McKim JM. 1985. Early life stage toxicity tests. In Rand GM (1995). Fundamentals of Aquatic Toxicology: Effects, Environmental Fate, and Risk Assessment (2nd ed.). Boca Raton: CRC Press. pp 974–1010. ISBN 1-56032-091-5.
↑ Organisation for Economic Co-operation and Development. 1992. Guideline 210: Fish early-life stage toxicity test. OECD Guidelines for the Testing of Chemicals. Paris, France.
↑ Mount DI, Stephan CE. 1967. A method for establishing acceptable limits for fish-Malathion and the butoxyethanol ester of 2,4-D. Trans Am Fish Soc 96:185-193.
↑ McKim JM. 1977. Evaluation of tests with early life stages of fish for predicting long-term toxicity. J Fish Res Board Can 34:1148–1154
↑ Hansen DJ, Parrish PR, Schimmel SC, Goodman LR. 1978. Life-cycle toxicity test using sheepshead minnows (Cyprinodon variegatus). Bioassay Procedures for the Ocean Disposal Permit Program, EPA-600/9-78-010.

[1] McKim JM. 1985. Early life stage toxicity tests. In Rand GM (1995). Fundamentals of Aquatic Toxicology: Effects, Environmental Fate, and Risk Assessment (2nd ed.). Boca Raton: CRC Press. pp 974–1010. ISBN 1-56032-091-5.

[2] Organisation for Economic Co-operation and Development. 1992. Guideline 210: Fish early-life stage toxicity test. OECD Guidelines for the Testing of Chemicals. Paris, France.

[3] Mount DI, Stephan CE. 1967. A method for establishing acceptable limits for fish-Malathion and the butoxyethanol ester of 2,4-D. Trans Am Fish Soc 96:185-193.

[4] McKim JM. 1977. Evaluation of tests with early life stages of fish for predicting long-term toxicity. J Fish Res Board Can 34:1148–1154

[5] Hansen DJ, Parrish PR, Schimmel SC, Goodman LR. 1978. Life-cycle toxicity test using sheepshead minnows (Cyprinodon variegatus). Bioassay Procedures for the Ocean Disposal Permit Program, EPA-600/9-78-010.

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