Accumulation and Effects of Nodularin from a Single and Repeated Oral Doses of Cyanobacterium <Emphasis Type="Italic">Nodularia spumigena</Emphasis> on Flounder (<Emphasis Type="Italic">Platichthys flesus</Emphasis> L.)

Nodularin (NODLN) is a cyclic pentapeptide hepatotoxin produced by the cyanobacterium Nodularia spumigena, which occurs regularly in the Baltic Sea during the summer season. In this study flounder (Platichthys flesus L.) was orally exposed to NODLN either as a single dose or as three repeated doses 3 days apart. Liver and bile samples of the fish were taken 4 days after the last dose. Liver glutathione-S-transferase (GST) activity was also measured and the histopathology of the liver was investigated. The liver of the exposed fish was analyzed by liquid chromatography-mass spectrometry for NODLN concentration. The content of NODLN-like compounds in the bile was analyzed by enzyme-linked immunosorbent assay. NODLN exposure caused slightly incoherent liver architecture and degenerative cell changes in both groups. The mean liver GST activity was significantly higher in the repeatedly dosed flounders than in the singly dosed flounders or in the control. In conclusion, the significantly lower NODLN concentration and the increased GST activity in the liver of the repeatedly dosed flounders compared to the singly dosed flounders suggest that NODLN is rapidly detoxificated. The absence of NODLN glutathione conjugates and the low concentrations of NODLN-like compounds in the bile indicate that detoxification products disintegrate or they are rapidly excreted.     

Effects of Nitrite and Toxic <Emphasis Type="Italic">Microcystis Aeruginosa</Emphasis> PCC7806 on the Growth of Freshwater Rotifer <Emphasis Type="Italic">Brachionus Calyciflorus</Emphasis>

Over the last two centuries, anthropogenic activities have increased the nitrogen amount in aquatic ecosystems, which has resulted in increased occurrences of blooms of cyanobacteria. This study investigated the effects of nitrite and the cyanobacterium Microcystis aeruginosa on population growth in the rotifer Brachionus calyciflorus. The rotifer was treated for 12 days with nitrite alone (medium containing 0, 3, 6, 10 mg NO₂ ⁻ –N L⁻¹), M. aeruginosa alone (medium containing 0 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at 0, 3, 6, 10 mg NO₂ ⁻–N L⁻¹), and nitrite in combination with M. aeruginosa (medium containing 3, 10 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at corresponding nitrite concentrations). We observed that a nitrite concentration of 10 mg NO₂ ⁻–N L⁻¹ markedly inhibited the growth of B. calyciflorus; however, rotifer growth declined slightly in the presence of M. aeruginosa precultured at 6 mg NO₂ ⁻–N L⁻¹. Furthermore, reduced population growth of B. calyciflorus was observed when it was treated with both nitrite and M. aeruginosa compared to nitrite alone or M. aeruginosa alone. These results suggested that a high tolerance of B. calyciflorus to nitrite levels may be attributed to the absence of specific respiratory structures and pigments; and that the increased toxicity of nitrite in combination with M. aeruginosa may have been due to increased production of microcystin. It is also possible that nitrite and microcystin could act in a synergistic way in causing toxicity.     

Effect of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis> on the rotifer <Emphasis Type="Italic">Brachionus calyciflorus</Emphasis> at different temperatures

Rotifers are one of the smallest metazoans. They serve as a model organism for ecotoxicological studies. More than 60% of the lakes in China are increasingly eutrophic and they are susceptible to blooms of Microcystis aeruginosa. We investigated the effects of M. aeruginosa on the survival and reproduction of Brachionus calyciflorus using the life table method at different temperatures. The findings showed that concentration of M. aeruginosa significantly affected the intrinsic rate of increase (r_m), net reproductive rate (R₀), average lifespan (L) and offspring number (p < 0.05). Temperature also significantly affected the generation time (T), average lifespan (L) and offspring number (p < 0.05). Moreover, the interaction between temperature and concentration had statistically significant effects on offspring number (p < 0.05). M. aeruginosa suppressed the survival and reproduction of B. calyciflorus, particularly at a concentration of 10⁶ cells/mL. The r_m values of the rotifers exposed at 10⁶ cells/mL decreased more than 200% compared with those of the control group. However, at a lower concentration, 10⁴ cells/mL, M. aeruginosa may supply appropriate nourishment to rotifers. In addition, at concentrations of 10⁵ and 10⁶ cells/mL, the inhibition of rotifers by M. aeruginosa heightened with increasing temperature.     

Biochemical Response of the Copepod <Emphasis Type="Italic">Tigriopus japonicus</Emphasis> Mori Experimentally Exposed to Cadmium

The response of the copepod (Tigriopus japonicus Mori) to cadmium (Cd) additions was investigated under laboratory-controlled conditions in a 12-day exposure. Superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), acetylcholinesterase (AchE), reduced glutathione (GSH), the ratio of reduced to oxidized glutathione (GSH/GSSG), and metallothionein (MT) were analyzed for Cd treatments (0, 10, 20, 40, and 100 μg/L) after exposure for 1, 4, 7, and 12 days. Additionally, thiobarbituric reactive species assay was used to evaluate lipid peroxidation (LPO) of the copepod after the 12-day exposure. The results indicated that Cd treatments significantly influenced the biochemical indexes (SOD, GPx, GST, AchE, GSH, and GSH/GSSG) after certain exposure times. Exposure to Cd induced LPO in the treated copepods, hinting that the copepods had suffered from oxidative damage. During exposure, the Cd initiated an induced MT synthesis in the copepods by day 7, which peaked at day 12 and which was probably responsible for Cd detoxification. Thus, Cd exposure significantly affected the detoxification process and antioxidant system of this copepod, and T. japonicus could be used as a suitable bioindicator of exposure to Cd using SOD, GPx, GST, LPO, and GSH/GSSG as biomarkers.     

Mercury and Selenium Content in <Emphasis Type="Italic">Otolithes ruber</Emphasis> and <Emphasis Type="Italic">Psettodes erumei</Emphasis> from Khuzestan Shore,Iran

In this paper the level of selenium and mercury is analyzed in edible part and liver of Psettodes erumei and Otolithes ruber two commercial fish in Persian Gulf. The average concentration of Hg and Se in edible parts of P. erumei was 0.077 ± 0.062 and 0.044 ± 0.018 (μg g⁻¹ww), and in liver was 0.127 ± 0.122 and 0.132 ± 0.610 (μg g⁻¹ww) respectively. In O. ruber, the average concentration of Hg and Se in edible parts was 0.348–0.27 and 0.06 ± 0.021 (μg g⁻¹ww) and in liver was 0.176 ± 0.174 and 0.093 ± 0.022 (μg g⁻¹ww), respectively. P. erumei has higher mean molar ratio Se/Hg (1.98) compared to O. ruber (0.88).     

Selective Bactericidal Potential of Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L. var. <Emphasis Type="Italic">japonica</Emphasis>) Hull Extract on <Emphasis Type="Italic">Microcystis</Emphasis> Strains in Comparison with Green Algae and Zooplankton

We examined the selective inhibitory potential of rice hull extract on the toxic cyanobacterium Microcystis aeruginosa, in comparison with inhibitory effects on two green algae (Ankistrodesmus convolutus and Scenedesmus quadricauda) and a zooplankton (Daphnia magna) species. The inhibitory effect of rice hull extract, measured by algal growth or zooplankton survival using four different concentrations of extract (1, 10, 100 and 1000 μg L⁻¹), was highest on Microcystis strains (average: 98%, range: 95%–99%), followed by D. magna (average: 22%, range: 10%–47%), A. convolutus (average: 20%, range: 16%–24%), and S. quadricauda (average: 8%, range: 0%–15%). Rice hull extract had only a small effect on the growth of the green algae and Daphnia, particularly in the range 1–100 μg L⁻¹, and the inhibitory effect was somewhat diminished even at the 1,000 μg L⁻¹ level, at the end of the experimental period, especially for Daphnia. Our study indicates that rice hull extract has a strong specific algicide potential when used to combat M. aeruginosa.     

Toxicity of Chiral Pesticide <Emphasis Type="Italic">Rac-</Emphasis>Metalaxyl and <Emphasis Type="Italic">R-</Emphasis>Metalaxyl to <Emphasis Type="Italic">Daphnia magna</Emphasis>

Chirality in pesticides has become a challenge because of enantiomers’ different toxicities to non-target organisms. Acute and chronic toxicities of Rac-metalaxyl and R-metalaxyl to Daphnia magna were determined and compared. The 48-h LC50 for Rac- and R-metalaxyl to Daphnia magna were 51.5 and 41.9 mg/L. In a 14-day chronic test, the lowest-observed-effective concentration (LOEC) and no-observed-effective concentration (NOEC) of Rac-metalaxyl were 2 and 1 mg/L, respectively, whereas those of R-metalaxyl were 1 and 0.1 mg/L. Body length, days-to-first-brood and number of broods per female were significantly (p < 0.05) affected by R-metalaxyl at >1.0 mg/L, but affected by Rac-metalaxyl at ≥2.0 mg/L.     

Fertilizer Industry Effluent Induced Biochemical Changes in Fresh water Teleost, <Emphasis Type="Italic">Channa striatus</Emphasis> (<Emphasis Type="Italic">Bloch</Emphasis>)

The industrial activities pose threat to the life of aquatic organisms in many ways. This research communication presents an account of the impact of fertilizer industry effluent upon the levels of protein and the activity of lactate dehydrogenase (EC 1.1.1.28, LDH), a terminal key enzyme in glycolytic pathway, in different organs of a fresh water teleost fish, Channa striatus (Bloch). The fish exposed to different sublethal concentrations of fertilizer industry effluent (3.5, 4.7 and 7.0% v/v) equivalent to 1/20th, 1/15th and 1/10th of LC₅₀ value (70% v/v) for varying treatment periods (96 h and 15 days) exhibited decrease in the level of protein (8–76%) in different organs of the effluent treated fish. At highest effluent concentration (7% v/v) treatment for short (96 h) or long (15 days) duration, the liver of the fish registered significant (p < 0.001) decrease (62–76%) in protein content as compared to control, whereas other organs of the fish showed only 38–52% decrease in the level of protein. The industrial effluent also caused marked reduction in the activity of LDH in different fish tissues when compared to the control. The treatment of fish with 7% effluent concentration for 96 h caused 78% decrease (p < 0.001) in the LDH activity in fish muscle whereas after 15 days the effect was maximum in fish brain as it exhibited 86% decrease (p < 0.001) in LDH activity as compared to control. The effect of effluent on the activity of LDH and protein content in different body tissues of the fish was dependent on concentration and duration of exposure. The significant reductions in the activity of LDH and level of protein in fish tissues due to treatment with the fertilizer industry effluent indicated the possibility of impairments in energy metabolism and protein turnover, respectively, in C. striatus.     

Mixture Toxicity Assessment of Nickel and Chlorpyrifos in the Sea Bass <Emphasis Type="Italic">Dicentrarchus labrax</Emphasis>

The present research work was designed to study Dicentrarchus labrax biotransformation and detoxification responses to acute exposure to nickel (Ni) and chlorpyrifos (CHP). Sexually immature sea bass were treated by intraperitoneal injection of nickel chloride (500 μg kg⁻¹), chlorpyrifos (10 mg kg⁻¹), and their binary mixture for 1, 3, and 7 days. Ni and CHP accumulation was quantified in liver after the exposure periods. The following biological responses were measured: (1) NADPH cytochrome P450 reductase (NCR) activity, as phase I biotransformation parameter; (2) gluthathione S-transferase (GST) activity as a phase II conjugation enzyme, acetylcholinesterase activity, and metallothionein (MT) content. Ni bioaccumulation in the liver resulted in an increasing uptake up to 15.48 μg g⁻¹ wet weight (Ni-treated animals) and 16.73 μg g⁻¹ wet weight (mixture-treated animals) after 7 days of exposure. CHP accumulation showed a distinct pattern in animals exposed to the mixture of chemicals in comparison with CHP-treated animals. NCR activity exhibited a marked activation in CHP and mixture-treated animals. GST activity was significantly increased starting from 1 day exposure in CHP-treated animals and after 3 days in Ni-treated animals. MT accumulation increased in all conditions, with a marked synergetic effect after 7 days of exposure. These data should be carefully considered in view of the biological effects of mixture pollutants, particularly in fish farming conditions.     

Chronic Effects of <Emphasis Type="Italic">Pinus radiata</Emphasis> and <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> Kraft Mill Effluents and Phytosterols on <Emphasis Type="Italic">Daphnia magna</Emphasis>

Two kraft pulp mill effluents were compared in terms of their chronic toxicity to Daphnia magna. One resulted from pulping Pinus radiata and the other came from a parallel processing of Pinus radiata and Eucalyptus globulus (mixed kraft pulp mill effluent). The concentration of phytosterols found in the mixed kraft pulp mill effluent was higher than in the effluent from Pinus radiata, with values of 0.1082 and 0.02 μg/L, respectively. The phytosterols per se are responsible for 12.9% and 8.1% of the deviation from the natural shape, while the kraft pulp mill effluents account for 25.6%–27.8% of shape deviation. The role of β-sitosterol and stigmasterol is discussed in relation to endocrine disruption.     

Effects of Water Cadmium Concentrations on Bioaccumulation and Various Oxidative Stress Parameters in <Emphasis Type="Italic">Rhamdia quelen</Emphasis>

The effects of sublethal cadmium concentrations on oxidative stress parameters were evaluated in Rhamdia quelen. The fish were exposed to 0.44, 236, and 414 μg l⁻¹ cadmium for 7 and 14 days, followed by the same time periods for recovery. Enzymes, such as catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST), and indicators of oxidative stress, such as thiobarbituric acid-reactive species (TBARS) and protein carbonyl, were verified in fish tissues. In addition, the accumulation of cadmium was evaluated in these tissues. Our results indicate that CAT and GST levels decreased in gills after exposure periods associated with increased TBARS levels. In hepatic tissue, CAT, GST, TBARS, and protein carbonyl levels increased after 7 days of exposure, whereas SOD activity decreased after exposure for 14 days. In the kidney, TBARS levels decreased after exposure for 7 days and increased after exposure for 14 days. During the recovery periods, some variations persisted in gills, liver, and kidney. Cadmium accumulation was most significant in liver, followed by kidney and gills. These results indicate that cadmium concentrations studied invoke a stress response in silver catfish.     

The Effect of some Selected Pesticides on the Growth and Reproduction of Fresh Water <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>, <Emphasis Type="Italic">Chrysicthys nigrodigitatus</Emphasis> and <Emphasis Type="Italic">Clarias gariepinus</Emphasis>

Studies were carried out to determine the toxicity of some selected pesticides on fresh water fish in a tropical environment. The uptake of the pesticides lindane, pentachlorophenol (PCP), and propoxur, which are frequently used on farms, and in industries as well as by loggers and timber men on wood were studied in concrete ponds at the University of Cape Coast, in Ghana. The fish used for the study were Oreochromis niloticus, Clarias gariepinus, and Chrysicthys nigrodigitatus. They were obtained from cultured ponds in the Cape Coast and Mankessim districts in the Central Region and Weija Dam, in the Greater Accra region of Ghana. Single high lethal concentration (SD) or acute treatment and cumulative/chronic (or multiple minor) lethal concentration (CD) treatment were employed in administering the pesticides to the fish via water. Gas chromatograph electron capture detector analysis was done on the dead fish to see the extent of ingestion. The LC₅₀ values obtained for lindane on the three fish samples were as follows: Chrysicthys – 0.38 mg L⁻¹; Oreochromis – 0.42 mg L⁻¹, and Clarias – 1.2 mg L⁻¹. Mortalities occurred in fish within 3–5 days of application. For the PCP on Chrysicthys, Oreochromis, and Clarias species the LC₅₀ values were 0.42, 0.32 and 0.64 mg L⁻¹, respectively, for over a 2- to 3-day period. For a three-time influx period of propoxur the LC₅₀ for Chrysicthys, Oreochromis, and Clarias, were 22.0, 30.40, and 45.04 (all in mg L⁻¹), respectively. The results obtained indicated that the pesticides had adverse effects on the general growth and reproduction of fish as shown by gonadosomatic indices.     

Acute Effects of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis> from the Patos Lagoon Estuary,Southern Brazil,on the Microcrustacean <Emphasis Type="Italic">Kalliapseudes schubartii</Emphasis> (Crustacea: Tanaidacea)

Toxic blooms of the cyanobacterium Microcystis aeruginosa, a microcystin producer, have been observed in the past two decades in the Patos Lagoon estuary (southern Brazil). This cyanobacterium reaches the estuary from northern waters and accumulates as toxic blooms in the shallow margins of the environment. Microcystins are phosphatase (PP1 and PP2A) inhibitors and cause animal death via alteration of the liver cell cytoskeletons and intrahepatic hemorrhage. The massive accumulation of toxic material affects the survival of several benthonic estuarine local organisms. The tanaidacea Kalliapseudes schubartii is a benthonic estuarine species which occurs at high densities throughout the year in mixohaline areas of the Patos Lagoon. This microcrustacean is of high ecological relevance and plays an important role in the estuarine food web, as it is consumed on a large scale by estuarine fish. This work verifies the acute toxicity of aqueous extracts of M. aeruginosa RST9501 and of sediments spiked with lyophilized material of the same strain on K. schubartii; it also evaluates the sublethal effects on tanaidacean oxygen consumption rates and glycogen levels under acute exposure to M. aeruginosa aqueous extracts. The strain M. aeruginosa RST9501 was cultured in BGN/2 medium. The aqueous extracts were prepared using the lyophilized material from the strain cultures. Acute tests were performed over 96 h at a salinity of 15, at six toxic concentrations, and resulted in an average 96-h LC50 of 1.44 mg ml^–1. The spiked sediment tests were performed with a 10-day duration, using the lyophilized material in three proportions of powder/sediment and showed an average LC50 of 1.79 mg ml^–1. Oxygen consumption was determined after 24 and 48 h of incubation in adult organisms exposed to sublethal aqueous extract concentrations and showed a significant increase at the highest concentrations. This suggests alterations in the organisms metabolism by exposure to the cyanobacterium extract. The glycogen levels were determined with a commercial kit (Glicox 500; DOLES Ltd.); after 24 and 48 h the dosages were administered in the same organisms utilized in the oxygen consumption test and did not demonstrate significant differences. The results demonstrate the possible risks of intoxication to which the natural populations of K. schubartii were exposed in the environment and emphasize the importance of studies involving sublethal concentrations of M. aeruginosa to other organisms of the trophic web in this aquatic system.     

Sediment-Quality Assessment Using the Polychaete <Emphasis Type="Italic">Arenicola marina</Emphasis>: Contamination,Bioavailability, and Toxicity

The sediment quality of Cádiz Bay, Las Palmas de Gran Canaria (LPGC) Port, Santander Bay, Algeciras Bay, and Huelva Estuary (Spain) was evaluated by analysing a battery of biochemical biomarkers―activities of biotranformation enzymes ethoxyresorufin O-deethylase [EROD], dibenzylflourescein dealkylase [DBF], and glutathione S-transferase [GST]; activity of antioxidant enzyme glutathione reductase [GR]; and lipid peroxidation [LPO]―in the polychaete Arenicola marina after laboratory sediment exposure. Huelva Estuary polychaetes showed significantly (p < 0.05) enhanced LPO, GST, and EROD activities compared with control lugworms related to metals and presumably polychlorinated biphenyls. EROD activity significant (p < 0.05) induction was associated polycyclic aromatic hydrocarbons after Santander Bay sediment exposure. Nickel appeared to significantly (p < 0.05) induce GR activity and LPO in LPGC Port sediment–exposed organisms. DBF activity significantly (p < 0.05) increased in polychaetes exposed to sediments from sewage-contaminated areas. A. marina was sensitive at the biochemical level. Integration of sediment characterization and biomarker results allowed the identification of polluted sites as well as the cause of possible sediment toxicity.     

Toxicity of Sediment-Associated Pesticides to <Emphasis Type="Italic">Chironomus dilutus</Emphasis> and <Emphasis Type="Italic">Hyalella azteca</Emphasis>

Two hundred sediment samples were collected and their toxicity evaluated to aquatic species in a previous study in the agriculturally dominated Central Valley of California, United States. Pyrethroid insecticides were the main contributors to the observed toxicity. However, mortality in approximately one third of the toxic samples could not be explained solely by the presence of pyrethroids in the matrices. Hundreds of pesticides are currently used in the Central Valley of California, but only a few dozen are analyzed in standard environmental monitoring. A significant amount of unexplained sediment toxicity may be due to pesticides that are in widespread use that but have not been routinely monitored in the environment, and even if some of them were, the concentrations harmful to aquatic organisms are unknown. In this study, toxicity thresholds for nine sediment-associated pesticides including abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin were established for two aquatic species, the midge Chironomus dilutus and the amphipod Hyalella azteca. For midges, the median lethal concentration (LC₅₀) of the pesticides ranged from 0.18 to 964 μg/g organic carbon (OC), with abamectin being the most toxic and propargite being the least toxic pesticide. A sublethal growth endpoint using average individual ash-free dry mass was also measured for the midges. The no–observable effect concentration values for growth ranged from 0.10 to 633 μg/g OC for the nine pesticides. For the amphipods, fenpropathrin was the most toxic, with an LC₅₀ of 1–2 μg/g OC. Abamectin, diazinon, and methyl parathion were all moderately toxic (LC₅₀s 2.8–26 μg/g OC). Dicofol, indoxacarb, oxyfluorfen, propargite, and pyraclostrobin were all relatively nontoxic, with LC₅₀s greater than the highest concentrations tested. The toxicity information collected in the present study will be helpful in decreasing the frequency of unexplained sediment toxicity in agricultural waterways.     

Trophic Transfer of Lead Through a Model Marine Four-Level Food Chain: <Emphasis Type="Italic">Tetraselmis suecica</Emphasis>, <Emphasis Type="Italic">Artemia franciscana,Litopenaeus vannamei</Emphasis>, and <Emphasis Type="Italic">Haemulon scudderi</Emphasis>

The objective of this investigation was to assess the transfer of lead (Pb) along an experimental, four-level food chain: Tetraselmis suecica (phytoplankton) → Artemia franciscana (crustacean, brine shrimp) → Litopenaeus vannamei (crustacean, white shrimp) → Haemulon scudderi (fish, grunt). T. suecica was exposed to a sublethal dose of Pb in solution and then used as the base of a marine food chain. Significant differences in Pb concentrations were found between exposed organisms of the different trophic levels and the control. Particularly, Pb concentrations in fish of the simulated trophic chain were two-to three times higher in the exposed specimens than in the control. Levels of Pb in phytoplankton showed a substantial increase with respect to the solution (level I), with bioconcentration factors averaging from 930 to 3630. In contrast, a strong decrease in Pb concentration from phytoplankton to zooplankton (level II) and from zooplankton to shrimp tissues (level III) was evidenced by bioaccumulation factors <1. Despite the decrease in the assimilation efficiency of metal transfer observed in these two predators, Pb concentration in the grunt fish (level IV) was higher than in the shrimp (level III) (bioaccumulation factor >1.0). Some of the added Pb is transferred from the phytoplankton along the food chain, thus producing a net accumulation of Pb mainly in fish and, to a lesser extent, in shrimp tissues. Because Pb is one of the most pervasive contaminants in coastal ecosystems, its transference by way of diet and potential net accumulation in higher predators is of ecologic importance for marine life. In addition, because shrimp and adult Haemulon scudderi are commercially important resources, this issue is of particular relevance to the safety of marine products.     

Copper Accumulation and Tolerance in <Emphasis Type="Italic">Chrysanthemum coronarium</Emphasis> L. and <Emphasis Type="Italic">Sorghum</Emphasis><Emphasis Type="Italic">sudanense</Emphasis> L.

In the present study, the growth of Chrysanthemum coronarium L. and Sorghum sudanense L. and their copper accumulation were studied using hydroponic experiments. Results showed that the root elongation, dry biomass yield, and chlorophyll content in both plant species decreased significantly with the increasing level of Cu in solution. The concentrations of Cu in the two plants increased greatly with the increasing Cu level in the treatments. However, most of the Cu was accumulated in roots, and only a small portion was translocated into shoots. Compared with S. sudanense, the shoots of C. coronarium had a significantly higher concentration of Cu. The total amount and percentage of water-soluble Cu, and the nonprotein thiol were also higher in the shoots of C. coronarium. In the roots, however, S. sudanense accumulated more Cu than C. coronarium. The treatments with 5 to 50 μmol L⁻¹ Cu significantly increased the uronic acid content in the roots of S. sudanens, but did not have any significant effect for C. coronarium. Higher concentrations of Cu bound to the cell wall and uronic acid in the roots of S. sudanense were speculated to be the main reason to restrain Cu translocation from roots to shoots.     

Cadmium Accumulation and Antioxidant Responses in <Emphasis Type="Italic">Sparus aurata</Emphasis> Exposed to Waterborne Cadmium

Cadmium (Cd), a nonessential trace element, is rapidly accumulated by most living organisms and subsequently exerts its toxicity at different molecular levels. This study exposed gilthead sea bream (Sparus aurata) to waterborne 0.1 mg/l Cd for 11 days and investigated the Cd accumulation pattern, lipid oxidation, and response of antioxidant defences. At the end of the experiment, mean Cd concentrations in gills and liver, the organs most prone to metal accumulation, were 209.4 and 371.7 ng/g ww, respectively. Muscle did not show any Cd retention during the 11 days of exposure. In liver, the cytosolic fraction of the metal was chelated into the nontoxic form by metallothionein (MT), a specific Cd-inducible protein. Zn and Cu concentrations were not influenced by Cd exposure. Glutathione (GSH) concentrations and the antioxidant enzyme activities of GSH reductase and GSH peroxidase showed an overall decreasing trend. In addition, lipid and aqueous hydroperoxide levels did not show any significant variation. Oxidative stress indirectly generated by Cd seems to be compensated for by the different biochemical systems tailored to decrease cellular damage. In particular, the negative effects of Cd accumulation in tissues were probably counteracted by the induction of MT.     

Monitoring of Traffic-Related Pollution in a Province of Central Italy with Transplanted Lichen <Emphasis Type="Italic">Pseudovernia</Emphasis><Emphasis Type="Italic">furfuracea</Emphasis>

The ability of transplanted lichen Pseudevernia furfuracea to biomonitor specific airborne pollutants (heavy metals and polycyclic aromatic hydrocarbons—PAHs) was investigated at five stations with different traffic densities in Viterbo, Italy. Exposed lichen showed high levels of all analysed pollutants; greatest values were for Zn (147–252 μg/g dw), Pb (24.9–34.6 μg/g dw), fluoranthene (37–107 ng/g dw), pyrene (23–124 ng/g dw). Comparison between contaminants concentration in lichens before and after exposure showed “accumulation” or “severe accumulation” rates in more than 90% of each substance. Besides, Pseudevernia furfuracea accumulated airborne PAHs in a manner that was proportional to traffic density.     

Oxidative Stress Response in Gill and Liver of <Emphasis Type="Italic">Liza saliens</Emphasis>, from the Esmoriz-Paramos Coastal Lagoon,Portugal

Tissue-specific responses against oxidative stress and lipid peroxidation were analyzed in wild adult mullet (Liza saliens) caught in the Portuguese coastal lagoon Esmoriz-Paramos. Parameters measured were catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST) activities in liver and gill tissues and lipid peroxidation. The enzyme activities were related to gill histopathological alterations, as well as to heavy metals (Cu and Zn) concentrations in these tissues. Gill epithelium of L. saliens showed histological alterations, such as epithelial hyperplasia resulting in lamellar fusion, epithelial lifting, vasodilatation, and lamellar aneurisms, with a prevalence ranging from 62% to 92%. The highest Cu content was found in liver (379 mg·kg⁻¹), while the highest Zn content was observed in gill (119 mg·kg⁻¹). SOD and CAT activities showed differences between gill and liver. The highest activities found were SOD in gill (10.1 U/mg protein) and CAT in liver (39.2 mmol/min/mg protein). In gill, CAT activity was negatively related to both Cu levels and gill lifting, while a positive relationship was found between SOD activity and fish age. The positive relationship between Cu and CAT activity in liver suggests that an increase in metabolic level is related to Cu-induced oxidative stress. The decrease in gill CAT activity can be due to osmotic stress caused by damaged gill epithelium. CAT activity in liver is an appropriate biomarker of oxidative stress in the Esmoriz-Paramos lagoon.