•
w
..
This paper not to be cited without prior reference tothe author
c.m. 1972/E:4
Improvement Committee
Tho
Tensides in Seawater
by
H. mann*)
In previous investigations the effect of anionactive tensides (Bock
and Mann 1968, mann
cm
1968/E:2) it was foundthat the toxicity of the
anionactive tensides increasedwith increasing salinity though the
quantity of the .dissolved tensides was not changed. In further investigations we observed that the surface tension decreased with equal content
of tensiden but inereasing salinity. Thus, e.g., the surfaee tension of
fresh water amounted to about 50 dyn/ern at a eontent of 10 ppm TPS (tetra
propylene benzol sulphonate), whereas it deereased to 40 dyn/cm at the
same content of tensides but with a salinity of 26
%0.
From investigations
which Bock (1966) earried out we know that damages to the gills of fish
oecur if the su~face tension of water decreases to under.50 d~n/em. This
explains why a cuncentration of 10 mg/lof anionactive tensides in fresh
water does not yet have a toxic effeet, but causes damages already at
a salinity of about 30%0. These findings are applieable to anionactive
substanees.
For yearn non-ionogen tensides have been used for eertain purposes besides
anionactive tensides. According to information from the industry their
~
sharo in the total eonsumption oftensides in the Federal Republie of
Germany amounts to about 20%. This figure has not ehanged for several
years.
With hausehold and industrial sewages these substanees enter inland and
also eoastal waters.
~e,
therefore, investigated the effect of non-ionogen
tensides in water of different salinity, and used for this purpose a
lauryl aleohol (ffiarlipal) with 7 AEO and a phosphorie acid ester-ethyl
adduct (Bill 7151).
In order to invostigate whether the non-ionogen tensides aet in a similar
mannor as the anionactive tensides, ws determined ths surface tension of
*) Dr.H.Mann, Institut für Küsten-und Binnenfischerei,
2 Hamburg 50, Palmaille 9, Germany
2/-
- 2 -
fresh, brackish and seawater with different content of non-ionogen
tensides. It has been found that the surface tension is rsduced corresponding
to tho content of tensides and that salinity does not exert any influence.
As an example the figures of the surface tension, which were obtained by
the addition of increasing quantities of non-ionogen tensides, are given
in the appended table. No difference has been found between fresh water
and seawater; the small fluctuations are duo to the measuring method (see
appended table).
Under these circumstances also the toxicity values for fish should not
show any difference when they are tested in fresh water and seawoter
with equal content of tensides. W8 found that concerning 8el the LD
SO
amounted after 24 hrs. to 5 mg/l of lauryl alcohol 7 AEO and 7,5 mg/l of ...
phosphoric acid ester-ethyl oxide adduct 12 - 14 C atoms. These values
applied to sea-, brackish and fresh water. No differences due to the
salinity did, therefore, oceur. It is of importanee that such contents
of non-ionogen tensides have not been found in the waters of the Federal
Republie of Germany. Aeeording to investigations earried out by Bock and
Wickbald (oral information) eontents of only 0,01 - 0,U3 mg/l ~f nonionogen tensides have been identified in inland and eoastal waters.
,
,
- 3 -
f
Table
Reduction of the surfece tension by a non-ionogen tenside (phosphoric
ester-ethyl oxide adduct with 12 - 14 C atoms (Bill 7151»
brackish water
seawater
30,5,,;;0
Content of
tensides
fresh
water
U,5 ppm
67
66,5
62
1
11
63,5
62,U
58,0
5
"
49,5
51
50,0
10
11
43,5
46,0
43,5
50
11
37,0
37,5
37,0
15, 6/~o
REFERENCES
K~J.;
1966
Über die Wirkung von Waschrohstoffen
auf Fische
Arch.Fisch.Wiss.17, G8-77
(1)
Bock,
(2)
Bock,K.J., u.H.mann;
196fJ
Die Bedeutung des Salzgehaltes für die
Wirkung von Tensiden
Ber. Dtsch.Wiss.Komm.Meeresforsch.
20 (3/4): 278-201
(3)
mann,H.: 1968
The Effect of Salinity on the Toxicity
of Syndets
C.n1. 1968/E:2
(4)
mann, H.:1972
Beiträge zur Wirkung nichtionogener
lliaschrohstoffe auf Fische und Fischnährtiere des BraCKwassers
(Im Druck)