De Boeck, G.

Diricx, M.

Loaiza, I.

Open Marine Archive

INTRODUCTION	  	  Heavy	  metal	  pollution	  in	  aquatic	  environments	  is	  a	  concern	  due	  to	  increasing	  human	  activities	  over	  the	   last	   decades.	   Moreover,	   productive	   areas	   such	   as	   estuaries	   have	   been	   even	   more	   affected	  because	  their	  complex	  interaction	  between	  =luvial	  and	  marine	  processes.	  	  European	  sea	  bass	  Dicentrarchus	  labrax	  l.	  is	  a	  euryhaline	  species	  that	  withstands	  large	  variations	  in	  salinity	  and	  is	  considered	  as	  a	  bioindicador	  due	  to	  their	  economic	  and	  ecological	  importance.	  	  	  Copper	   as	   essential	   micronutrient	   has	   important	   roles	   in	   cellular,	   enzymatic	   and	   protein	  mechanisms	  but	  is	  potentially	  toxic	  when	  its	  concentration	  increases	  above	  a	  certain	  threshold,	  and	  cadmium	   is	   an	   ubiquitous	   and	   extremely	   toxic	   element,	   that	   does	   not	   have	   any	   functionality	   for	  living	  organisms;	  hence	  it	  is	  good	  indicator	  of	  pollution.	  	  	  The	  96h-­‐LC50	  test	  is	  used	  as	  an	  indicator	  of	  toxicity	  worldwide,	  and	  gives	  the	  lethal	  concentration	  where	  50%	  of	  the	  population	  dies	  within	  96	  hours	  of	  exposure.	  
MATERIALS	  AND	  METHODS	  
RESULTS	  AND	  DISCUSSION	  
	  	  	  	  	  	  	  	  	  
	  
OBJECTIVES	  
	  Determine	  the	  96h-­‐LC50	  values	  in	  acute	  exposure	  scenario’s	  for	  Cu	  and	  Cd	  over	  a	  broad	  salinity	  range	  in	  juvenile	  (±	  9cm)	  European	  sea	  bass	  D.	  labrax	  l.	  	  
THE	  EFFECT	  OF	  SALINITY	  ON	  THE	  ACUTE	  TOXICITY	  OF	  COPPER	  AND	  
CADMIUM	  IN	  EUROPEAN	  SEA	  BASS	  Dicentrarchus	  labrax	  L.	  
	  	   	  Loaiza	  Iván1,2,	  Diricx	  Marjan2,	  De	  Boeck	  Gudrun2	  	  1	  Marine	  and	  Lacustrine	  Science	  and	  Management	  (Oceans	  and	  Lakes),	  Faculty	  of	  Science	  and	  Bioengineering	  Science,	  Vrije	  Universiteit	  Brussel	  (VUB),	  Brussels,	  Belgium.	  	  2	  SPHERE	  –	  Systematic	  Physiological	  and	  Ecotoxicological	  Research,	  University	  of	  Antwerp,	  Antwerp,	  Belgium.	  	  	  	  	  E-­‐mail:	  ivan.loaiza.alamo@vub.ac.be;	  marjan.diricx@ua.ac.be;	  gudrun.deboeck@ua.ac.be	  	  
Cd 
Cu 
Cd 
Cu 
Cd 
Cu 
Cd 
Cu 
S‰=	  2.5	  S‰=	  1	   S‰=	  5	   S‰=	  10	   S‰=	  20	   S‰=	  28	   S‰=	  35	  
0	  
-­‐	  2
00
00
	  μ
gC
d	  
L-­‐
1 	  	  
[C
d]
	  
B B B B 
[C
u]
	  
0	  
-­‐	  5
10
0	  
μg
Cu
	  L
-­‐1
	  
 each 4 hrs. for 10 days 
Cd 
Cu 
B 
Cd 
Cu 
B 
Cd 
Cu 
B 
CONCLUSIONS	  	  Juvenile	  euryhaline	  European	  sea	  bass	  D.	  labrax	  	  are	  less	  sensitive	  to	  Cd	  than	  Cu.	  	  Salinity	  regulates	  toxicity	  differently	  for	  Cu	  and	  Cd,	  indicating	  that	  besides	  competition	  by	  cations	  and	  metal	  speciation,	  the	  changing	  physiology	  at	  different	  salinities	  plays	  an	  important	  role.	  	  Future	  analysis	  of	  tissue	  samples	  will	  indicate	  whether	  differences	  in	  sensitivities	  can	  be	  explained	  by	  metal	  accumulation	  rates.	  	  	  
•  D.	  labrax	  showed	  to	  be	  the	  least	  sensitive	  to	  Cd,	  the	  96h-­‐LC50	  ranged	  from	  1	  659	  to	  16	  256	  μg	  L-­‐1	  from	  1	  to	  20	  ppt	  and	  >20	  000	  μg	  L-­‐1	  at	  28	  and	  35	  ppt,	  while	  for	  Cu,	  it	  ranged	  from	  1	  163	  to	  6	  835	  μg	  L-­‐1.	  
•  Importance	  of	  salinity	  in	  the	  toxicity	  of	  Cu	  and	  Cd	  during	  acute	  exposure.	  Cu	  è	  mortality	  =irst	  decreased	  with	  increasing	  salinity	  but	  increased	  again	  at	  higher	  salinities	  (28	  and	  35ppt)	  (Fig	  1).	  
•  Individuals	  were	  affected	  in	  different	  ways,	  for	  instance	  Cu	  exposed	  =ish	  at	  low	  salinity	  showed	  open	  gills	  at	  die-­‐off.	   
Cd	  è	  mortality	  decreased	  continuously	  with	  increasing	  salinity,	  to	  a	  point	  where	  no	  reliable	  LC50	  could	  be	  determined	  at	  the	  2	  highest	  salinities	  (28	  and	  35ppt)	  (Fig	  2).	  
ACKNOWLEDGES	  
	  This	  research	  was	  supported	  by	  SPHERE	  -­‐	  Systematic	  Physiological	  and	  Ecotoxicological	  Research	  group	  and	  Oceans	  &	  Lakes	  program.	  Fig 1. Acute Cu toxicity to european sea bass  D. labrax as 96h-LC50 at different salinities  
Fig 2. Acute Cd toxicity to european sea bass  
D. labrax as 96h-LC50 at different salinities  
0	  
1000	  
2000	  
3000	  
4000	  
5000	  
6000	  
7000	  
0	   5	   10	   15	   20	   25	   30	   35	  
LC
50
	  (μ
g	  
L-­‐1
)	  
Salinity	  (‰)	  
Cu 
0	  
2000	  
4000	  
6000	  
8000	  
10000	  
12000	  
14000	  
16000	  
18000	  
0	   5	   10	   15	   20	  
LC
50
	  (μ
g	  
L-­‐1
)	  
Salinity	  (‰)	  
Cd 
	  The	  96h-­‐LC50	  values	  were	  calculated	  by	  the	  bioassay	  analysis	  of	  dose-­‐response	  curve	  (drc)	  using	  R.	  	  


The effect of salinity on the acute toxicity of copper and cadmium in European sea bass <i>Dicentrarchus labrax</i> L.

 - 63 -  
The effect of salinity on the acute toxicity of copper and cadmium in 
European sea bass Dicentrarchus labrax L. 
Loaiza Iván
1,2
, Marjan Diricx
2
 and Gudrun De Boeck
2
 
1 
Marine and Lacustrine Science and Management (Oceans and Lakes), Faculty of Science and 
Bioengineering Science, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium  
E-mail: ivan.loaiza.alamo@vub.ac.be   
2 
Systematic Physiological and Ecotoxicological Research (SPHERE), University of Antwerp, 
Groenenborgerlaan 171, 2020 Antwerp, Belgium 
E-mail: marjan.diricx@ua.ac.be; gudrun.deboeck@ua.ac.be  
 
Contamination by heavy metals in aquatic environments is a serious concern due to increasing 
human activities over the last decades. Moreover, productive areas such as estuaries have even 
been more affected because of the complex interaction between fluvial and marine processes, 
creating a stressful environment with gradients of salinity and other important parameters which 
can intensify negative effects of pollutants on biota such as euryhaline fish (Mieiro et al., 2012; 
Oliva et al., 2012). European sea bass (Dicentrarchus labrax L.) is an euryhaline species able to 
withstand a large variation in salinity and is considered as a bioindicator due to both economic and 
ecological importance (Loizeau, 2001; Schnitzler et al., 2011). Copper as essential micronutrient 
has important roles in cellular, enzymatical and protein mechanisms but is potentially toxic when 
its concentration increases above a certain threshold (Blanchard and Grosell, 2005; Grosell et al., 
2007), and can even be more toxic than cadmium, a non-essential metal (Roméo et al., 2000) which 
is ubiquitous in environment and one of the most deleterious heavy metal pollutants (Nath et al., 
1984 cited by Loaiza, 2011). Therefore, the effect of salinity on the acute toxicity of copper and 
cadmium in European sea bass D. labrax L. was examined to determine 96h-LC50 values (the lethal 
concentration where 50% of the population dies) at different exposure concentration of both metals 
(at 0 to 5100μgCu.l-1 and at 0 to 20000μgCd.l-1) over a broad salinity range (1, 2.5, 5, 10, 20, 28, 
35‰) in juvenile sea bass during a period of 10 days. The results showed an important influence of 
the salinity in the toxicity in both elements, where for Cu mortality first decreased with increasing 
salinity but increased again at higher salinities and for Cd, mortality decreased continuously with 
increasing salinity, to a point where no reliable LC50 could be determined at the 2 highest salinities. 
In addition, it was observed that the individuals were affected in different ways. For instance Cu 
exposed fish at low salinity showed opened gills at die-off. Copper is readily taken up by the gill, 
where it inhibits the action of Na+/K+ adenosine triphosphatase, resulting in an osmoregulatory 
disturbance as Na+ is lost to the dilute external environment (Blanchard and Grosell, 2006). In 
conclusion, the salinity influences the toxicity differently for Cu and Cd. This not only occurs due to 
the fact that salinity plays an important role in the speciation of pollutants and competition by 
cations in uptake processes, but as can be clearly seen in the case of Cu, also by the physiology of 
the fish that responds to the changes in the environment. Further research on the relationship 
between bio-accumulation of the metals and the mortality at different salinities is planned. 
 
 
Keywords: Dicentrarchus labrax L.; salinity; acute exposure. 
 
 
References 
Blanchard J. and M. Grosell. 2005. Effects of salinity on copper accumulation in the common killifish 
(Fundulus heteroclitus). Environmental toxicology and chemistry 24(6):1403–1413. 
Blanchard J. and M. Grosell. 2006. Copper toxicity across salinities from freshwater to seawater in 
the euryhaline fish Fundulus heteroclitus: Is copper   an ionoregulatory toxicant in high 
salinities? Aquatic Toxicology 80:131–139. 
Grosell M., J. Blanchard, K.V. Brix and R. Gerdes. 2007. Physiology is pivotal for interactions 
between salinity and acute copper toxicity to fish and invertebrates. Aquatic Toxicology 
84:162–172. 
Loizeau V. 2001. A steady-state model of PCB bioaccumulation in the sea bass (Dicentrarchus 
labrax) food web from the Seine Estuary, France. Estuaries 24:1074–87. 
 - 64 -  
Loaiza I. 2011. Bioacumulación de cadmio y plomo en concha de abanico Argopecten purpuratus 
(Lamarck, 1819) en cultivo de fondo, en Parachique - Bahía de Sechura. Tesis. Facultad de 
Pesquería. UNALM 
Mieiro C.L., J.P. Coelho, M. Pacheco, A.C. Duarte and M.E. Pereira. 2012. Trace elements in two 
marine fish species during estuarine residency: Non-essential versus essential  . Marine 
Pollution Bulletin (in press). 
Oliva M., J.J. Vicente, C. Gravato, L. Guilhermino and M.D. Galindo-Riaño. 2012. Oxidative stress 
biomarkers in Senegal sole, Solea senegalensis, to assess the impact of heavy metal pollution in 
a Huelva estuary (SW Spain) seasonal and spatial variation. Ecotoxicol. Environ. Saf. 75:151–
162. 
Roméo M., N. Bennani, M. Gnassia-Barelli, M. Lafaurie and J.P. Girard. 2000. Cadmium and copper 
display different responses towards oxidative stress in the kidney of the sea bass 
Dicentrarchus labrax. Aquatic Toxicology 48:185–194. 
Schnitzler J.G., J.P. Thomé, M. Lepage and K. Das. 2011. Organochlorine pesticides, polychlorinated 
biphenyls and trace elements in wild European sea bass (Dicentrarchus labrax) off European 
estuaries. Science of the Total Environment 409:3680–3686. 


The effect of salinity on the acute toxicity of copper and cadmium in European sea bass <i>Dicentrarchus labrax</i> L.

Abstract

Similar works

Full text

Available Versions

Open Marine Archive

Open Marine Archive