Environmental monitoring by gene expression biomarkers in Barbus graellsii: laboratory and field studies

Barbel (Barbus graellsii) is a freshwater fish used as a sentinel species in environmental monitoring programmes and ecotoxicological studies in northern Spain, particularly in the Ebro River basin, the largest freshwater resource in Spain. We developed specific primers for the quantification of CYP1A and metallothionein (MT)-1 and -2 gene expression by QRT-PCR in barbel in order to assess their suitability in biological effect monitoring of dioxin-like compounds and metals. All three genes responded as expected in laboratory tests, using model inducers. Hepatic CYP1A mRNA levels showed a twofold induction in fish injected intraperitoneally with beta-naphthoflavone, whereas MT-1 and MT-2 gene expression was strongly induced by cadmium (15- and 13-fold, respectively) and mercury (five- and eightfold). Barbel populations from different sites on the Ebro River basin showed a good correlation between the historical records of organochlorine pollution, CYP1A expression levels and EROD activity. Nevertheless, although metallothionein protein levels in the liver of wild fish correlated with hepatic levels of mercury, MT-1 and MT-2 gene expression did not correlate with the mercury content or with the concentration of metals in sediments from the sites inhabited by the fish. These results demonstrate the utility of barbel CYP1A-mRNA expression, but not that of MT-1 or MT-2, as a biomarker in field studies. The tools and protocols developed here are likely to apply to other species of the genus Barbus, with some 700 species distributed throughout most of the Old World.     

Anionic surfactant linear alkylbenzene sulfonates (LAS) in sediments from the Gulf of Gdańsk (southern Baltic Sea, Poland) and its environmental implications

Linear alkylbenzene sulfonate (LAS) is a group of anionic surfactants employed in the formulation of laundry and cleaning products, with a global production rate of 4 million metric tons. Sediments from the Polish coast of the southern Baltic Sea were collected at ten stations. Total LAS concentrations, measured by high-performance liquid chromatography, were between 0.04 and 0.72 mg LAS·kg(-1) dry weight. Highest LAS concentrations were found in suspended matter collected from the Vistula River, sediment collected close to the Vistula River mouth and from the Gdańsk Deep, known as the depositional area. With the obtained environmental LAS concentrations, a risk assessment for this surfactant has been carried out, based on publicly available acute and chronic toxicity data in target organisms. The results indicated that LAS could pose a low risk for the existing benthic community applying worst case scenario assessment. This is the first time that levels of LAS have been measured in environmental samples of the southern Baltic Sea.     

Occurrence of perfluorinated compounds in water and sediment of L’Albufera Natural Park (València,Spain)

Purpose  

Perfluorinated compounds (PFCs) are widely distributed from industrialized to remote locations throughout the world. This study demonstrates the spatial distributions of PFCs in water and sediments from the L’Albufera Natural Park (Valencia, Spain).     

Spatial distribution of illicit drugs in surface waters of the natural park of Pego-Oliva Marsh (Valencia,Spain)

Background, aim and scope  

The Pego-Oliva Marsh is the second most important wetland in the Valencian Community (Spain). It is included in the RAMSAR agreement and represents one key point for migratory birds. Emerging contaminants from the human pressure, such as pharmaceuticals, illicit drugs and personal care product, are not included in the list of priority contaminants of the Water Framework Directive yet, and are neither monitored nor controlled. However, pollution of emerging contaminants can threaten the environment and even human health. In order to understand the status of the emerging contamination and recommend future rationalization of countermeasures, the occurrence of illicit drugs was investigated.     

Heavy metal bioavailability and effects: II. Histopathology-bioaccumulation relationships caused by mining activities in the Gulf of Cádiz (SW, Spain)

The relationship between bioaccumulation of heavy metals (Zn, Cd, Pb and Cu) and histological lesions in different tissues of organisms is assessed in three different areas located in the southwest of Spain in the Gulf of Cádiz (Ría of Huelva, Guadalquivir estuary and Bay of Cádiz) affected and non-affected by mining activities. Data included in these relationships were obtained along the years 2000 and 2001 to address the impact of the Aznalcóllar mining spill on the Guadalquivir estuary. The bioaccumulation and the histological lesions measured in this seasonal study in the Gudalquivir estuary were linked to derive tissue quality guidelines (TQGs) by means of a multivariate analysis approach (MAA). Sediments collected in the same areas of study were used to expose organisms during the survey carried out in autumn 2001 and to address the relationship between bioaccumulation and histological lesions under laboratory conditions and related to chemicals bound to sediments. Lesions show that the organisms collected in the ría of Huelva and exposed to their sediments were severe, intermediate in the Guadalquivir estuary and absent in the Bay of Cádiz. Results show that the Guadalquivir estuary trends to recover its initial status quo previous to the mining spill. The link between chemical concentration and the lesions measured in the same tissues using MAA permits to derive tissue quality guidelines for two organisms, oysters (Crassostrea angulata) and clams (Scrobicularia plana) collected in the Guadalquivir estuary and associated with the heavy metals from the mining spill (Zn and Cd). The TQG values expressed as concentrations (mgkg-1--dry weight) not associated with biological effects are for oysters, Zn, 8603, Cd, 3.42; and for clams Zn, 800, Cd, 2.6.     

Acid and alkaline phosphatase activities in the clam Ruditapes philippinarum

Acid and alkaline phosphatase activities have been partially characterized in Ruditapes philippinarum (Adams and Reeve, 1850). Two activity peaks at pH=4.5 and pH 10.5 were detected in the gill, digestive gland, mantle, siphon and foot. Acid phosphatase activity was higher than that of alkaline phosphatase. The highest activity for both enzymes was observed in the digestive gland and, in decreasing order, the gill, foot, siphon and mantle. Alkaline phosphatase activity was similar in the mantle, siphon and foot. K _m values were determined for both enzymes in the gill and digestive gland. Hill coefficients were near 1, indicating no allosteric behaviour for either enzyme in the two organs. The optimum temperature was the same for acid phosphatase in both gill and digestive gland (50 °C), while for alkaline phosphatase it differed for these two organs (gill, 40 °C; digestive gland, 35 °C). The apparent activation energy was obtained from Arrhenius plots, and ranged from 8.61 kcal/mol for alkaline phosphatase in the gill, to 10.84 kcal/mol for acid phosphatase in the digestive gland. The effects of metals (1 mM conc) on both enzyme activities were assayed in vitro. Hg strongly inhibited the enzyme activities in the gill and digestive gland, probably because of its affinity for the sulphydryl group. Histochemically, acid phosphatase in the gill was located in a granular form throughout the gill cells, but was undetectable in the ciliate epithelium of the gill filaments. Alkaline phosphatase was located in the gill skeleton. Clam size and phosphatase activities were inversely related, probably reflecting a decrease in shell deposition with inereasing size. As a function of season, both enzymes were present in lowest amounts in winter, when undifferentiated sex cells were predominant in the germinative epithelium, and highest in summer, when ripe individuals of both sexes were more frequent.