POLLUTION IN THE KISHON ESTUARY AND FISHING HARBOUR

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22 févr. 2014 (il y a 3 années et 10 mois)

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POLLUTION IN THE
KISHON
ESTUARY AND FISHING HARBOUR
*)


Menakhem Ben
-
Yami

2 Dekel St., Kiryat Tiv’on 36056

Ph. +972
-
4
-
983
-
5928

benyami@actcom.net.il

,
www.benyami.org


Starting with th
e 1960s’ the lower Kishon River

has gradually become
a carrier of some 15,000
cu.m/day of poisonous and carcinogenous industrial, and municipal

effluents

that turned Kishon into
a dead river, lethal to all life, and corroding metals at a
fast rate.
. The river has become a polluted
sewer, and the fishing harbour to it sedimentation
-
pond

that both its water and bottom comprise
poisonous and carcinogenous matters in concentrations exceeding by tens and even hundreds times
the permited standar
ds. Among those pollutants
were

found also voluble materials known as
carcinogenous, which
also
caused heavy air pollution in the area.

At the ascent of the 20
th

century
,

the epidemics of cancer among marine commandos and Kishon based fishermen,
and

corros
ion
damage to boats anchoring in the Kishon harbour and to the harbour’s mooring installations
,

has
awakened public attention to

the extent of the pollution
. This led to the setting up of an investiga
tory

(Shamgar) commission

and various litigations.



O
ut

of many polluters, a few major plants
have been

responsible for about 90% of the
pollutants flowing in the Kishon
, above all


Haifa Chemicals, Haifa Refinery, Carmel Ulpinim,
Gadot, Gadiv,
and the
waste
-
water treatment

plant
(
WWTP
)
serving Haifa area. Cr
ude oil and

its derivat
ive
s is the main source of organic substances and nickel found in the fishing
harbour’s sediments.

WWTP

is supplying s
ome 100,000 cu.m/day of effluents comprising
organic substances

and also some 800
-
900 mt of fluorid.

Haifa Chemical
s
has been releasing
to Kishon 14 mt/day of dense acid liquid, rich in suspended heavy metals.

The annual
contribution of heavy metals by this plant to Kishon
has been
:

chrome
-

10 mt; copper


2.6 mt;
cadmium


2.3 mt; nickel 8.4 mt; zinc


54 mt, and sma
ller amounts of lead, arsenic, and
mercury.


All these figures are based on data

submitted by the polluting plants.
However, t
he managing
director of the Kishon River authority

told the Shamgar commision that plants
have been
omitting or understating extr
eme

flow
and pollutants concentrations
values
.


In spite of improvements initiated at the end of the last century, Kishon remains the most
polluted of Israel’s rivers. Its catchment area covers the Ezdrelon Valley, Mt.Carmel slopes,
Menasse, and the sout
he
rn parts of the Lower Galilee.

It flows through Israel’s largest industrial
area and receives on the way large amounts of pollutants. Its estuary, including the
commercial and fishing harbours, is approximately at sea level, and is affected by tides. Duri
ng
weak summer flow,
seawater

flows a few kilometres upstream.

Most of the time, the amount of
clean water entering Kishon is small in relation to that of the effluents. Thus, the liquid, which
flows in it is filthy and smelly. The slow current facilitate
s sedimentation of the pollutants in the
bottom sludge, so that only part of them reaches the sea.


The fishing harbour represent
s an artificial pond, dug out in

the right (north) riverside, just
upstream
from

the comm
ercial harbour, and its entrance tends

to silt up. Most studies of
Kishon and its pollution sidest
epp
ed the fishing harbour, hence less data than on the remaining
parts of the Kishon system.


Due to its topography and flow conditions, the fishing harbour traps more pollutants than any
other s
ection of the estuary. One reason for this is the Coriolis force
, a rightwise vector (in the
northern hemisphere),
which makes certain that the polluted water enters the fishing harbour.
The water flowing west to the sea tend to enter it more than the tide

driven seawater flowing
east
, but t
he fishing harbour is a sedimentation pond for both.


Winter floods
flush

part of the

river
-
bed sludge to the sea, but not that of

the fishing harbour.
For example, in the 1991 flood, not only that the fishing harbour wa
s not “cleaned”, but its
entrance was silted up.
According to measurements carried out between 1987 and 1991,
during the d
redging executed
in the entrance
every

2
nd

or 3
rd

year to a depth of 4 m, a 2
-
m
deep polluted sledge fo
und in 1991 accumulated during
2½ years.


The mechanism, which enables
the

sedimentation

of pollutants
to the fishing harbour’s bottom,
is as follows: the polluted water that enter the harbour are mostly acid (very low pH), which
does not support sedimentation of

heavy metals

However,
t
he not acid, heavy seawater that
enters the fishing harbour in flood tide doesn’t mix well with the Kishon water,
thus

creat
ing

stratification. In the interface, however, and whenever
revolving
boats’propellers
mix the two
layers, the acidity is reduced an
d conditions created for
deposit of
the heavy metals

on the
bottom. T
he

seawater
’s
thus conducts

the pollutants from the upper layer to the bottom sledge.
Notwithstanding, each time a boat activates its propeller, some pollutants are raised back into
the w
ater, where they remain for a while
, before they settle back
.


Public outrage, litigation and establishment of the Kishon River Authority,
have created
pressure towards reducing the pollution, but there’s still long way to go to return to Kish
o
n its
life a
nd health.


======================================================================================


*) Submitted to the 2006 Annual Conference of Israel Society for Aquatic Research and
Mariculture.