Impact assessment of agricultural inputs into a Mediterranean coastal lagoon (Mar Menor, SE Spain) on transplanted clams (Ruditapes decussatus) by biochemical and physiological responses

Abstract

The Mar Menor is a coastal lagoon threatened by the development of intensive agriculture in the surrounding areas. Large amounts of pesticides from these areas are discharged into El Albujón, a permanent watercourse flowing into the lagoon. We have used a multi-biomarker approach to assess the biological effects of agricultural pollution on a bivalve species. Biomarkers indicative of neurotoxicity (acetylcholinesterase, AChE), oxidative stress (catalase, CAT; glutathione reductase, GR and lipid peroxidation, LPO), phase II biotransformation of xenobiotics (glutathione S-transferase, GST) and physiological stress (scope for growth, SFG) were measured in clams transplanted to four sites of the lagoon (two reference sites and two sites affected by the dispersion of the effluent of the El Albujón), for exposure periods of 7 and 22 days. The hazards of this effluent were also examined by simultaneously measuring up to 83 contaminants (pesticides, PCBs, PAHs and others) in samples of fresh water from the watercourse mouth and seawater from the deployed sites, as well as the bioaccumulation of organochlorinated compounds and PAHs in the transplanted animals. Biomarker responses showed marked differences between reference and affected sites after 7 and 22 days. However it was only after 22 days that principal component analysis (PCA) of the biomarker responses distinguished between clams deployed in sites affected by the dispersion of the effluent of the watercourse and those from the reference sites. The chemical analysis of water showed high concentrations of pesticides close to El Albujón watercourse mouth, with the greatest input flux corresponding to the organophosphate chlorpyrifos, followed by pendimethalin and naphthalene, and at lower levels acenaphthene, terbuthylazine-desethyl and chlorpyrifos-methyl. In this regard, PCA analysis showed that the biological effects of the mixture of pesticides in caged clams after 22 days were reduced levels of AchE and SFG and increased levels of GR and phase II GST activity. An integrated biomarker response index was calculated from the combination of these biomarkers, proving useful for the assessment of the impact of agricultural pollution in caged clams.

Temporal and spatial distribution of semicarbazide in western Laizhou Bay

“…The IBR approach has also been widely used to investigate both native and caged bivalves in many studies (Leinio and Lehtonen, 2005;Campillo et al, 2013;Marigomez et al, 2013aMarigomez et al, , 2013b. In this study, IBR/n showed a significant difference among the sampling sites, with XZ site having the highest IBR/n value of 3.58.…”

“…However, the CAT activity of oysters from XZ was significantly inhibited compared to other sites, which was likely related to higher levels of heavy metals at this site. Previous studies have recorded that mussels caged in the polluted sites showed lower CAT activity than that in the reference mussels (Viarengo et al, 2007;Campillo et al, 2013). On the other hand, the oxidative stress in organisms may also induce lipid peroxidation, resulting in increased MDA level (Kamel et al, 2014).…”

“…This is an increase in evidence revealing that exposure to contaminants could induce the production of ROS, resulting in toxic effects on antioxidant system as well as cellular damage, protein degradation and DNA damage (Livingstone et al, 1993). Antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPO) have been frequently used as effect biomarkers to assess the contaminated area by caged and native bivalves (Leinio and Lehtonen, 2005;Viarengo et al, 2007;Campillo et al, 2013;Turja et al, 2013). Glutathione S-transferases (GSTs) represent a main group of phase II detoxification enzymes involved in the detoxification of organic pollutants (Sheehan et al, 2001).…”

“…Presently, a wide range of biomarkers has been increasingly used as sensitive early warning tools for the assessment of environmental variables caused by chemical contaminants in coastal areas (Campillo et al, 2013;Marigomez et al, 2013a;Bellas et al, 2014). Oxidative stress is essentially an imbalance between cellular production of reactive oxygen species (ROS) and an organism's ability to detoxify the reactive intermediates.…”

Effect of nutritive status on Mytilus galloprovincialis pollution biomarkers: Implications for large-scale monitoring programs

“…All of them have been used to reveal the exposure to a wide range of pollutants, both metals and organic compounds (Campillo et al, 2013;Fernández et al, 2010Fernández et al, , 2012Regoli, 1998;Akosan et al, 1997). SOD is the enzyme responsible of the formation of hydrogen peroxide H 2 O 2 , after removal of the superoxide anion (O 2 − ) (Regoli and Giuliani, 2014), which makes necessary its coordination with other H 2 O 2 enzymes such as CAT, which is an extremely active catalyst for reduction of H 2 O 2 to H 2 O at high levels of H 2 O 2.…”