Rapp. Comm. int. Mer Médit., 36,2001
110
Introduction
Anionic surfactants, the main constituents of modern laundry and
industrial detergents, have been widely used throughout the world
since early 1960s. World consumption of these synthetic surfactants
significantly increases every year [1]. The most important sources of
anionic detergents in the marine environment are land-based sources.
The detergents are introduced into the sea directly from outfalls or
through coastal dispersion, and indirectly through rivers, canals or
other watercourses. Coastal water and estuaries are acknowledged not
only as the most productive but also very sensitive areas of biological
activity which could be seriously endangered if the self-depuration
capacity of the environment is not high enough to remove anthro-
pogenic pollutants [2]. Therefore, it is important to monitor the level
of these widespread contaminants in seawater especially considering
that urban coastal areas in Croatia are direct recipients of untreated
municipal and industrial waste waters.
Materials and Methods
Study areas and sampling.The Adriatic Sea represents a region in the
Mediterranean with significant gradients of physical, biological and
chemical oceanographic parameters [3]. Seawater samples used for
anionic surfactants analyses were collected at the stations located at
500-1800 m distance from main urban and industrial centers along the
Croatian coast, i.e. from Pula (Northern Adriatic) down to Dubrovnik
(Southern Adriatic). Sampling was performed seasonally during a one
year period from November 1998 until August 1999. All samples were
collected using 5 l Niskin bottles at the depths of 0 m and 5 m.
Analytical method. International Standard Method ISO 7875-1:1996
for determination of anionic surfactants by measurement of the methy-
lene blue index (MBAS) was used. Prior to MBAS determination, the
concentration and separation of surfactants by a stripping (solvent
sublation) procedure was performed.
Results and Discussion
The presence of anionic surfactants in marine environment indicates
mostly contamination with modern household detergents. Owing to
the relatively scarce data on the level of anionic surfactants in the
Adriatic Sea and the increased concentrations of these pollutants noted
in municipal waste water of coastal towns, there was an urgent need to
perform systematic monitoring of anionic surfactants levels in all
urban coastal areas that may be affected by untreated waste waters.
The concentrations of anionic surfactants in the surface layer (0 m)
of coastal seawater in the vicinity of main urban and industrial centers
are presented in Table 1. It is evident that surfactant concentrations
determined as MBAS index in most cases were below 10 µg/L and on
some occasions values were slightly higher (10,4-17,3 µg/L). The con-
centrations of anionic surfactants at 5 m depth were in general lower
or similar as those in the surface layer (0 m). Although these relative-
ly low concentrations of anionic surfactants in seawater do not indicate
significant pollution of coastal areas by detergents, it is important to
note that chronic and sublethal effects of linear alkylbenzensulfonates
(widely used anionic surfactants) in some marine organisms have been
reported even at concentrations as low as 5-10 µg/L [4]. Significantly
higher concentration levels were observed in seawater near the points
of discharge of untreated waste water.This was especially evident in
semi-enclosed Sibenik Harbour (240-620 µg/L MBAS) near the main
outlet, and in Kastela Bay (195-250 µg/L MBAS) which receives
untreated municipal and industrial waste waters from Split, the largest
town in the Middle Adriatic. The concentrations observed in the prox-
imity of untreated waste water outlets represent a risk for marine biota.
It was also found that anionic surfactants accumulate in sediments
close to waste water outlets, a finding which represent a potential dan-
ger to benthic communities [4].
References
1. Hrsak D. 1996. Cometabolic transformation of linear
alkylbenzensulphonates by methanotrophs. Wat. Res. 30: 3092-3098.
2.Terzic S., Hrsak D. and Ahel M. 1992. Enrichment and isolation of
linear alkylbenzenesulphonate (LAS) degrading bacteria from estuarine
and coastal waters. Mar. Pollut. Bull.24: 199-204.
3. Degobbis D., Precali R., Ivancic I., Smodlaka N. and Kveder S. 1997.
The importance and problems of nutrient ?ux measurements to study
eutrophication of the northern Adriatic. Period. Biol.99: 161-167.
4. WHO/UNEP 1995. Assessment of the state of pollution of the
Mediterranean Sea by anionic detergents. Final report from Athens,
Greece (April, 1995). WHO/EURO Project Office-Mediterranean Action
Plan, Athens.
LEVELS OF ANIONIC SURFACTANTS IN COASTAL WATERS OF THE EASTERN ADRIATIC
A. Begonja Kolar*, D. Hrsak, M. Korolija and K. Horvat
Centre for Marine and Environmental Research, Rudjer Boskovic Institute, Zagreb, Croatia
Abstract
The concentrations of anionic surfactants were determined in the vicinity of urban centers along the Croatian coast, areas which may be
affected by untreated municipal and industrial waste waters. The concentrations obtained, determined as methylene blue active substance
(MBAS index), were mostly lower than 10 mg/L. Significantly higher concentrations of anionic surfactants (195-620 mg/L MBAS) which
could represent a risk for marine organisms have been found in the proximity of untreated waste water outlets.
Keywords: anionic surfactants, MBAS index, Adriatic Sea
Station
Nov 98Feb 99May 99Aug 99
µg/LMBAS
PUE 02
8.5ND
8.7
9.1
PUE 03
8.4ND
6.8
8.1
PUE 05
9.0ND
8.311.9
RI 20a
4.7ND
10.6
8.5
RI 10a
ND
ND
13.810.4
RI 007
4.3ND
5.8
8.1
CR 001
4.7ND
6.012.8
ZD 102
ND
4.912.5
8.6
ZD 103
8.9ND
10.5
9.0
ZD 104
5.9ND
8.8
7.3
SI 103
15.215.8ND
13.3
SI 201
ND
3.7ND
9.4
SI 203
7.5
5.8ND
6.6
SI 204
6.8
4.3ND
ND
ST101
8.611.2ND
6.6
ST102
7.310.5ND
8.4
ST103
7.012.8ND
ND
ST201
8.2
7.6ND
11.0
ST202
7.0
8.7ND
12.8
ST203
6.6
5.1ND
11.9
ST204
8.3
6.8ND
8.5
PL101
3.7
8.2
6.0
8.1
PL102
3.8
8.111.3
8.4
DU 002
3.611.817.3
8.5
DU 001
8.5ND
17.1
8.0
Table 1. Concentrations of anionic surfactants in surface sea-
water along the Eastern Adriatic coast expressed as the methy-
lene blue substance (MBAS index).
Areas of urban centers: Pula (PUE); Rijeka (RI); Crikvenica
(CR); Zadar (ZD); Sibenik (SI); Split (ST); Ploce (PL) and
Dubrovnik (DU).
