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Arsenic can enter the water through rockerosion, mining activity, etc.

When contaminated water is used to irrigatefelds, the element accumulates in soil and

crops, particularly rice.

In communities where residents cook that riceand drink water rom the contaminated well,

arsenic enter into human body.

Accumulation site o arsenic

Arsenic is a toxic metal-like element that is both naturally occurring in earths crust

and artifcially produced during agricultural and industrial processes. !ostly Arsenic

was used extensively in pesticides and herbicides until the late "#$%s which is nowbeen banned due to environmental and health issues.

In this report, we are going to review the accumulation site o arsenic in human.

Arsenic poisoning can be occurred by ingestion, inhalation and dermal absorption.

Arsenic III is well absorbed through the skin and is $% times more toxic than arsenic

&, which is well absorbed by the gut. 'he ma(or site o absorption is the small

intestine by an electrogenic process involving a proton )*+ gradient and the

optimal p* or absorption is .%.

'he two dierent orms may exert their eects in completely dierent ways. As)&

or arsenate. In the periodic table, arsenic is in the position (ust below phosphorus./hosphorus is used to build 01A and as the energy currency o the cell. 'hat means

that phosphate is crucial or lie. 2ince the arsenate looks a lot like the phosphate

molecule used in 01A and 31A synthesis, it can sometimes trick the transport

proteins or phosphate into importing arsenate rom outside the cell. 4nce inside,

arsenate may uncouple oxidative phosphorylation by competing with inorganic

phosphate and blocking A'/ synthesis )As+A0/ -5 unstable arsenate.

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As)III or arsenite works in a dierent way. 2ince it is missing the extra oxygen, it

doesn6t look much like phosphate to the cell, but because it is uncharged, it can

pass through the lipid membrane to the inside o the cell. 4nce inside, arsenite may

bind to sulhydryl groups )3-2*, thus reacts with a variety o proteins and inhibits

their activity )e.g7 pyruvate dehydrogenase, glutathione reductase and thioredoxin

reductase. Arsenite inhibits not only the ormation o Acetyl-8oA but also the

en9yme succinic dehydrogenase. 'hat may help to account or the wide range o

toxic eects o arsenic.

Ater acute poisoning o arsenic spectrometry studies show that the highest

concentration o arsenic is in the kidneys and liver. In chronic poisoning, arsenic

accumulates in the liver, kidneys, heart, and lungs and smaller amounts in the

muscles, nervous system, gastrointestinal tract, and spleen. 'he absorbed arsenic

undergoes hepatic biomethylation to orm monomethylarsonic acid)!!A and

dimethylarsinic acid)0!A that are less toxic. About %: o the ingested arsenic

may be eliminated in the urine in three to fve days. 0!A is the dominant urinarymetabolite )$%:;