Chemistry Reference
In-Depth Information
OH
Cl
Cl
Cl
Cl
Cl
HO
DDT
17
b
-Oestradiol
Cl
Cl
O
O
HO
Cl
Cl
A nonylphenol
2,3,7,
8
-Tetrachlorodibenzodioxin
Cl
Cl
Cl
HO
Cl
A PCB congener
Scheme 3.4
number of alkyl groups and chromium(III) and
chromium(VI) are significantly different in toxicity,
the latter being toxic and a known carcinogen.
tives and pesticides. Many percolate into the soil and
accumulate in aquifers and surface waters, some-
times reaching drinking water supplies. A recent
survey [20], for example, showed that over 20% of
private water supplies in Wales are contaminated
with sheep dip chemicals.
Some of the most widely used solvents in the UK
are the chlorocarbons CH
2
Cl
2
, CHCl
3
, CCl
3
CH
3
, CCl
4
,
Synthetic organic chemicals
.
A wide range of
organic compounds are synthesized for industrial
and agricultural use, including drugs, solvents,
cleaners, degreasers, petroleum products, preserva-
