,".'.d(P: - Higher Education Commission

fo. *dr qlrlity .xaoidrion is de @nsid.Ed &c'P!able' vat't q!2liiv bed o' a
st nddd of hs lhe on€ colifom ter loonl n *adstic'llv safe for hmd consuPdon
l\uro,19961.
AlSaI tosi6 @ 8*!allv caLgorized 6 lr@toxbs or hePatoloxins lhar d podlced
flom dinoflogellates, diarom. or cvmobad'rja (blue sten alsde) IRicbddon' 20031
Btm6 of cyeobscldia m gcn allv ioud h lalcs dd Esfloi6 6ed fo! potabl'
w1d supply. Cydotdcr€dal loxis cD atfect hul1r6 dtrough drinldng wter
1.2,.1 R.d iologic,l .ont Eimrr!
Radioacive subsances c @lv foud in dritling aaler' NaluEl occudence or
@!M (U) in grcundMrer n dsiar€d with saitic @ks 4d orhd oin'dl depdis
It is a kidney toxin [r!*.[ . l Nieu'€trhuile!, 2003t Radon (Rr) is a ddioedve gd
fom d. tsult of mhlal btcar.toh (dli@ctiv' &c6v) of BdiutrL rdich b ilself a
d{ay prcducl ofurdium. Radon is @inog'nic &d rh'rc is a @nvincing 'vid"e thal
ndon caues lug cscs The sociaton b€Neen ddon dd clildh@d dalisrdcies i3
ale Eponed in svdal sludid lKohli .l {' 20001
t3 Todc .tf.ci of D.ld3
Mecls e most litel, rhe old.sl roxins knM b hMes Toxi'ilv is det'mi"d bt do*
a! the celluld level as well as factos such 6 lalenc' state and ligmd binding' lor
ermplq rhe lival€nr +ei$ of chromiM e 'sctrtbl @e 'len€nl wh€r@ tn'
hdavaLnt cbrohiu h hiSl v toxic Ligdd birding is possiblv th€ mosr tuldmenbl
prce$ in Bd.l roxi.iiv md in celLule dcfense against nelals' The diol lismds of
deDllothio!.in avidlv biffl a nubd of !oxi' retals 6 p'rt of a d'fe6' svst'm k'd
anaches lo thiol ligsds on edlm€s iNolvcd in hem' sv hesi3' ufuiu to pho$hat'
groups on glncose tansponert md triwlsl @nic to lhe thiol goups of dlpha lipoic
eit! .ll lh* nclal lieand inl@tios udcdving loxic &riotr lKl.sc'' 201'll Mos
mebls af€ci nultiple olge svst ns al higho do*s but al the lowest dos' etch nelal
t nd. to .ILcr a sFcific orAe or risw otlv'