Tr\u01b0\u1edbc h\u1ebft ch\u00fang ta xem c\u1ea3nh t\u01b0\u1ee3ng sau: chim b\u1ecb ch\u1ebft h\u00e0ng lo\u1ea1t, s\u1ed1 \u00edt c\u00f2n s\u1ed1ng s\u00f3t \u0111ang ph\u1ea3i n\u1eb1m trong t\u1ed5, nh\u01b0ng tr\u1ee9ng ch\u00fang \u0111\u1ebb ra kh\u00f4ng th\u1ec3 n\u1edf th\u00e0nh con. M\u00f9a xu\u00e2n \u0111\u1ebfn hoa n\u1edf r\u1ed9 kh\u1eafp n\u01a1i nh\u01b0ng kh\u00f4ng c\u00f3 ong \u0111\u1ebfn l\u1ea5y m\u1eadt, kh\u00f4ng c\u00f3 ong truy\u1ec1n nh\u1ecb ph\u1ea5n. C\u00e2y ra qu\u1ea3 x\u1ea5u x\u00ed. Trong l\u00fac \u0111\u00f3 lo\u00e0i s\u00e2u b\u1ec7nh l\u1ea1i ph\u00e1t tri\u1ec3n r\u1ea5t nhi\u1ec1u. Hoa m\u00e0u v\u00e0 c\u00e2y \u0103n qu\u1ea3 \u0111\u1ec1u b\u1ecb ph\u00e1 ho\u1ea1i nghi\u00eam tr\u1ecdng. Con ng\u01b0\u1eddi r\u01a1i v\u00e0o t\u00ecnh tr\u1ea1ng \u0111\u00f3i kh\u1ed5 v\u00e0 b\u1ec7nh t\u1eadt. \u0110\u00f3 l\u00e0 \u00e1c m\u1ed9ng ch\u0103ng? Kh\u00f4ng ph\u1ea3i, qu\u1ea3 th\u1ef1c tr\u00ean Tr\u00e1i \u0110\u1ea5t m\u00e0 ch\u00fang ta sinh s\u1ed1ng \u0111ang x\u1ea3y ra \u0111i\u1ec1u \u0111\u00f3. \u0110\u00f3 l\u00e0 v\u00ec nh\u1eefng tai h\u1ecda to l\u1edbn do thu\u1ed1c tr\u1eeb s\u00e2u DDT v\u00e0 thu\u1ed1c 666 mang l\u1ea1i cho con ng\u01b0\u1eddi.<\/p>\n\n\n\n
DDT l\u00e0 ch\u1eef vi\u1ebft t\u1eaft ti\u1ebfng Anh c\u1ee7a h\u00f3a ch\u1ea5t Dichlo-Dibenzen-Trichlo ethan, do nh\u00e0 khoa h\u1ecdc \u00d4sth\u01a1man Xith\u01a1l\u01a1 ng\u01b0\u1eddi \u00e1o n\u0103m 1872 s\u1ea3n xu\u1ea5t ra. N\u0103m 1939 nh\u00e0 h\u00f3a h\u1ecdc Pao\u01a1 Niul\u01a1 ng\u01b0\u1eddi Th\u1ee5y S\u0129 ph\u00e1t hi\u1ec7n DDT c\u00f3 t\u00ednh n\u0103ng tr\u1eeb s\u00e2u r\u1ea5t t\u1ed1t, d\u00f9ng \u0111\u1ec3 di\u1ec7t c\u00e1c lo\u00e0i s\u00e2u ph\u00e1 ho\u1ea1i l\u01b0\u01a1ng th\u1ef1c, c\u00e2y \u0103n qu\u1ea3, rau xanh v\u00e0 c\u00e1c lo\u00e0i c\u00f4n tr\u00f9ng g\u00e2y b\u1ec7nh r\u1ea5t c\u00f3 hi\u1ec7u qu\u1ea3. Do \u0111\u00f3 DDT r\u1ea5t nhanh \u0111\u00e3 \u0111\u01b0\u1ee3c d\u00f9ng l\u00e0m thu\u1ed1c tr\u1eeb s\u00e2u tr\u00ean ph\u1ea1m vi r\u1ea5t r\u1ed9ng. V\u00ec t\u00ednh ch\u1ea5t c\u1ee7a DDT kh\u00e1 \u1ed5n \u0111\u1ecbnh, hi\u1ec7u qu\u1ea3 c\u1ee7a n\u00f3 l\u00e2u d\u00e0i, c\u1ed9ng th\u00eam n\u00f3 kh\u00f4ng d\u1ec5 h\u00f2a tan trong n\u01b0\u1edbc, sau khi phun thu\u1ed1c kh\u00f4ng b\u1ecb n\u01b0\u1edbc m\u01b0a r\u1eeda s\u1ea1ch, cho n\u00ean s\u1eed d\u1ee5ng n\u00f3 so v\u1edbi c\u00e1c lo\u1ea1i thu\u1ed1c tr\u1eeb s\u00e2u kh\u00e1c hi\u1ec7u qu\u1ea3 r\u1ea5t nhanh, kinh t\u1ebf h\u01a1n r\u1ea5t nhi\u1ec1u. Ngo\u00e0i ra DDT d\u1ec5 t\u1ed5ng h\u1ee3p, c\u00f3 th\u1ec3 s\u1ea3n xu\u1ea5t m\u1ed9t l\u01b0\u1ee3ng l\u1edbn v\u1edbi gi\u00e1 r\u1ebb. V\u00ec v\u1eady b\u1eaft \u0111\u1ea7u t\u1eeb n\u0103m 1943 thu\u1ed1c tr\u1eeb s\u00e2u DDT \u0111\u01b0\u1ee3c d\u00f9ng r\u1ed9ng r\u00e3i v\u1edbi m\u1ed9t l\u01b0\u1ee3ng l\u1edbn tr\u00ean to\u00e0n th\u1ebf gi\u1edbi.<\/p>\n\n\n\n
Lo\u00e0i ng\u01b0\u1eddi nh\u1eefng t\u01b0\u1edfng r\u1eb1ng v\u1ea5n \u0111\u1ec1 tr\u1eeb s\u00e2u h\u1ea1i \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft tri\u1ec7t \u0111\u1ec3 t\u1eeb \u0111\u00e2y. Song kh\u00f4ng may l\u00e0 sau khi s\u00e2u b\u1ec7nh l\u1eafng xu\u1ed1ng m\u1ed9t th\u1eddi gian th\u00ec ch\u00fang \u0111\u00e3 nh\u1eddn thu\u1ed1c DDT v\u00e0 bi\u1ebfn th\u00e0nh lo\u00e0i s\u00e2u c\u00f3 t\u00ednh nguy h\u1ea1i l\u1edbn h\u01a1n \u0111\u1ed1i v\u1edbi c\u00e2y l\u01b0\u01a1ng th\u1ef1c. L\u00fac \u0111\u00f3 thi\u00ean \u0111\u1ecbch c\u1ee7a s\u00e2u b\u1ec7nh \u0111\u00e3 b\u1ecb ti\u00eau di\u1ec7t ph\u1ea7n l\u1edbn. Nh\u1eefng lo\u1ea1i thu\u1ed1c tr\u1eeb s\u00e2u n\u00e0y \u0111\u1ed3ng th\u1eddi v\u1edbi hi\u1ec7u qu\u1ea3 ng\u00e0y c\u00e0ng gi\u1ea3m l\u1ea1i g\u00e2y \u00f4 nhi\u1ec5m r\u1ea5t nghi\u00eam tr\u1ecdng \u0111\u1ed1i v\u1edbi m\u00f4i tr\u01b0\u1eddng. V\u00ec t\u00ednh ch\u1ea5t c\u1ee7a ch\u00fang kh\u00e1 \u1ed5n \u0111\u1ecbnh, t\u1ed1c \u0111\u1ed9 ph\u00e2n gi\u1ea3i r\u1ea5t ch\u1eadm, n\u1ebfu mu\u1ed1n ti\u00eau gi\u1ea3m 95% DDT trong \u0111\u1ea5t ph\u1ea3i c\u1ea7n \u0111\u1ebfn 30 n\u0103m, v\u00ec v\u1eady ch\u00fang t\u1ed3n t\u1ea1i l\u00e2u d\u00e0i trong m\u00f4i tr\u01b0\u1eddng. Ph\u1ea1m vi khu\u1ebfch t\u00e1n c\u1ee7a DDT c\u0169ng r\u1ea5t r\u1ed9ng, n\u00f3 c\u00f3 th\u1ec3 tr\u00f4i theo n\u01b0\u1edbc v\u00e0 c\u00e1c d\u00f2ng s\u00f4ng, bay theo kh\u00f4ng kh\u00ed \u0111\u1ebfn kh\u1eafp m\u1ecdi n\u01a1i tr\u00ean th\u1ebf gi\u1edbi, sau \u0111\u00f3 l\u1ea1i r\u01a1i xu\u1ed1ng m\u1eb7t \u0111\u1ea5t c\u00f9ng v\u1edbi n\u01b0\u1edbc m\u01b0a. \u1ede Ch\u00e2u Nam C\u1ef1c v\u00e0 c\u00e1c \u0111\u1ea3o \u1edf B\u1eafc C\u1ef1c ng\u01b0\u1eddi ta \u0111\u00e3 ph\u00e1t hi\u1ec7n th\u1ea5y lo\u1ea1i thu\u1ed1c tr\u1eeb s\u00e2u n\u00e0y. C\u00f3 th\u1ec3 th\u1ea5y r\u00f5 ph\u1ea1m vi \u1ea3nh h\u01b0\u1edfng c\u1ee7a ch\u00fang l\u00e0 r\u1ea5t l\u1edbn. Ngo\u00e0i ra thu\u1ed1c tr\u1eeb s\u00e2u DDT trong m\u00f4i tr\u01b0\u1eddng th\u00f4ng qua sinh v\u1eadt t\u00edch l\u0169y v\u00e0 th\u00f4ng qua c\u00e1c chu\u1ed7i th\u1ee9c \u0103n c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00f3ng \u0111\u1ea1i v\u00e0 khu\u1ebfch t\u00e1n, c\u00f3 t\u00ednh nguy h\u1ea1i r\u1ea5t l\u1edbn \u0111\u1ed1i v\u1edbi con ng\u01b0\u1eddi v\u00e0 c\u00e1c lo\u00e0i sinh v\u1eadt kh\u00e1c. V\u00ed d\u1ee5 DDT ph\u00e1 ho\u1ea1i s\u1ef1 h\u1ea5p thu v\u00e0 \u0111\u00e0o th\u1ea3i b\u00ecnh th\u01b0\u1eddng \u0111\u1ed1i v\u1edbi canxi, khi\u1ebfn cho v\u1ecf tr\u1ee9ng m\u1ecfng h\u01a1n v\u00e0 d\u1ec5 v\u1ee1, khi\u1ebfn cho tr\u1ee9ng c\u1ee7a c\u00e1c lo\u00e0i chim kh\u00f4ng n\u1edf th\u00e0nh con. DDT c\u00f2n t\u00edch t\u1ee5 trong l\u1edbp m\u1ee1 c\u1ee7a c\u01a1 th\u1ec3 ng\u01b0\u1eddi, d\u1eabn \u0111\u1ebfn t\u00e1c h\u1ea1i cho gan, th\u1eadn v\u00e0 h\u1ec7 th\u1ed1ng th\u1ea7n kinh, g\u00e2y n\u00ean ng\u1ed9 \u0111\u1ed9c m\u00e3n t\u00ednh.<\/p>\n\n\n\n
Tuy thu\u1ed1c tr\u1eeb s\u00e2u DDT ch\u1ec9 s\u1eed d\u1ee5ng v\u1edbi s\u1ed1 l\u01b0\u1ee3ng l\u1edbn trong v\u00f2ng 20 n\u0103m, nh\u01b0ng t\u00e1c d\u1ee5ng ph\u00e1 ho\u1ea1i m\u00f4i tr\u01b0\u1eddng v\u00e0 sinh th\u00e1i c\u1ee7a ch\u00fang v\u00f4 c\u00f9ng to l\u1edbn, m\u1ea5y chu k\u00ec 20 n\u0103m n\u1eefa c\u0169ng ch\u01b0a th\u1ec3 b\u00f9 \u0111\u1eafp l\u1ea1i \u0111\u01b0\u1ee3c. B\u1eaft \u0111\u1ea7u t\u1eeb nh\u1eefng n\u0103m 60 c\u1ee7a th\u1ebf k\u1ec9 XX, r\u1ea5t nhi\u1ec1u n\u01b0\u1edbc k\u1ec3 c\u1ea3 Trung Qu\u1ed1c \u0111\u00e3 c\u1ea5m d\u00f9ng ho\u1eb7c h\u1ea1n ch\u1ebf s\u1eed d\u1ee5ng thu\u1ed1c tr\u1eeb s\u00e2u DDT.<\/p>\n\n\n\n
T\u1eeb kho\u00e1: DDT.<\/p>\n","protected":false},"excerpt":{"rendered":"
Tr\u01b0\u1edbc h\u1ebft ch\u00fang ta xem c\u1ea3nh t\u01b0\u1ee3ng sau: chim b\u1ecb ch\u1ebft h\u00e0ng lo\u1ea1t, s\u1ed1 \u00edt c\u00f2n s\u1ed1ng s\u00f3t \u0111ang ph\u1ea3i n\u1eb1m trong t\u1ed5, nh\u01b0ng tr\u1ee9ng ch\u00fang \u0111\u1ebb ra kh\u00f4ng th\u1ec3 n\u1edf th\u00e0nh con. M\u00f9a xu\u00e2n \u0111\u1ebfn hoa n\u1edf r\u1ed9 kh\u1eafp n\u01a1i nh\u01b0ng kh\u00f4ng c\u00f3 ong \u0111\u1ebfn l\u1ea5y m\u1eadt, kh\u00f4ng c\u00f3 ong truy\u1ec1n nh\u1ecb ph\u1ea5n. C\u00e2y […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[15,17],"tags":[],"class_list":["post-9310","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-moi-truong"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/9310","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=9310"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/9310\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=9310"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=9310"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=9310"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}