Comparative sensitivity of harbour and grey seals to several environmental contaminants using in vitro exposure

In this study, we investigated the effects of cadmium chloride (CdCl₂), mercury chloride (HgCl₂), methylmercury chloride (CH₃HgCl), and PCBs on lymphocyte proliferation in phocids. PBMCs isolated from harbour and grey seals were exposed in vitro to varying concentrations of contaminants. A reduction of viability occurred when cells were exposed to 10⁻⁴ M HgCl₂ or CH₃HgCl or to 50 ppm of Aroclor 1254. In both grey and harbour seals, T-lymphocyte proliferation was suppressed when their cells were incubated with 5 × 10⁻⁵ M CdCl₂ or 10⁻⁴ M HgCl₂. An inhibition of proliferation occurred with CH₃HgCl from 10⁻⁶ M in grey seals and from 10⁻⁵ M in harbour seals. In grey seals, Aroclor 1254 reduced lymphocyte proliferation at 15 ppm. In both harbour and grey seals, CH₃HgCl was ten times more immunotoxic that HgCl₂. From IC₅₀, chemicals were ranked in terms of toxicity as followed: CH₃HgCl > CdCl₂ > HgCl₂ > Aroclor 1254.     

Occurrence of anthropogenic and naturally-produced organohalogenated compounds in tissues of Black Sea harbour porpoises

Harbour porpoises are one of the three cetacean species inhabiting the Black Sea. This is the first study to report on polybrominated diphenyl ethers (PBDEs) and naturally-produced compounds, methoxylated PBDEs (MeO-PBDEs) and polybrominated hexahydroxanthene derivatives (PBHDs), in tissues (kidney, brain, blubber, liver, muscle) of male harbour porpoises (11 adults, 9 juveniles) from the Black Sea. Lipid-normalized concentrations decreased from muscle > blubber > liver > kidney > brain for the sum of polychlorinated biphenyls (PCBs) and for the sum of PBDEs. Among the naturally-produced compounds, levels of PBHDs were higher than of MeO-PBDEs, with tri-BHD and 6-MeO-BDE 47 being the dominant compounds for both groups, respectively. Concentrations of naturally-produced compounds decreased from blubber to brain, similarly to the sum of DDT and metabolites (DDXs). Concentrations of DDXs were highest, followed by PCBs, HCB, PBHDs, PBDEs and MeO-PBDEs. Levels of PCBs and PBDEs in blubber were lower than concentrations reported for harbour porpoises from the North Sea, while concentrations of DDXs were higher.     

Endocrine effects of methoxylated brominated diphenyl ethers in three in vitro models

Methoxylated brominated diphenyl ethers (MeO-BDEs) in aquatic environments have been found to be primarily of natural origin in the marine environment and not from biotransformation of synthetic PBDEs. Two of the eight MeO-PBDEs (2′-MeO-BDE-68 and 6-MeO-BDE-47) that were detected in anchovy from the Yangtze River Delta, were natural products from marine organisms. So 2′-MeO-BDE-68 and 6-MeO-BDE-47 were chosen to study the potential to modulate androgen, estrogen, or thyroid hormone receptor- (AR, ER, ThR) mediated responses by use of reporter gene assays. 2′-MeO-BDE-68 was antiandrogenic at 50 μM, estrogenic at 10 μM and antiestrogenic at 10 and 50 μM (IC₅₀ = 4.88 μM). 2′-MeO-BDE-68 enhanced luciferase expression by 5 nM T3 at 50 μM. 6-MeO-BDE-47 exhibited potent antiandrogenicity at 1 μM and greater (IC₅₀ = 41.8 μM) and possessed estrogenic activity at 10 μM and antiestrogenic activity at 10 and 50 μM (IC₅₀ = 6.02 μM).     

In vitro effects of nonylphenol on functional responses of haemocytes of the colonial ascidian Botryllus schlosseri

The effects of nonylphenol (NP) on functional responses of haemocytes of the colonial ascidian Botryllus schlosseri were evaluated. Haemocytes were exposed to 0.1, 1 and 10 μM NP and the effects on haemocyte viability, adhesion, morphology, lysosomal membrane stability, phagocytic activity and early apoptosis were evaluated. Haemocyte viability and adhesion were not affected by NP. Phagocytic activity and the amoebocytic index decreased significantly at all the concentrations tested, while exposure of haemocytes to 1 and 10 μM NP caused a significant increase in the diffusion of Neutral Red into the cytosol. The percentage of cells positive to Annexin-V (indicative of early apoptosis) increased significantly at 1 and 10 μM NP. Results obtained suggested a relationship between NP and alterations in functional responses of haemocytes in B. schlosseri. Biomarkers measured resulted sensitive, rapid and reproducible, even if their responsiveness will be evaluated after in vivo exposure of animals to NP.     

DDT in endangered Galapagos sea lions (Zalophus wollebaeki)

We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). ∑DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070 μg/kg lipid. Concentrations of ∑DDT in pups in 2008 averaged 525 μg/kg lipid and were 1.9 times higher than that (281 μg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p′-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed.     

Bioaccumulation and trophic transfer of polybrominated diphenyl ethers (PBDEs) in a marine food web from Liaodong Bay,North China

The concentrations of 21 polybrominated diphenyl ethers (PBDEs) congeners were analyzed in organisms within a marine food web collected from the Liaodong Bay, North China. The total concentrations of PBDEs in all samples ranged from 0.87 to 91.4 ng g⁻¹ lipid weight (lw). BDE-47 was the predominant congener and had a concentration ranging from 0.30 to 36.1 ng g⁻¹ lw. The trophic magnification factors (TMF) of the PBDEs were calculated using the trophic levels obtained from the stable nitrogen isotope ratios. The TMF value of ∑PBDEs was 3.50 for the entire food web and 2.21 for the food web excluding seabirds. Four concentration ratios, BDE-99/BDE-100, BDE-99/BDE-47, BDE-153/BDE-154 and BDE-183/BDE-154, decreased linearly with the increase of the trophic levels in the invertebrates and the fishes (p < 0.01). The results suggested that the PBDEs were steadily metabolized in the trophic transfer process along the food chain.     

The relationships between particulate and soluble alkaline phosphatase activities and the concentration of phosphorus dissolved in the seawater of Toulon Bay (NW Mediterranean)

The activities of particulate and soluble phosphatase were analyzed monthly for 1 year in the coastal ecosystems of the NW Mediterranean Sea. The mean contribution of the particulate activity increased from 56% at an MUF-P concentration of 30 μM to 77% at 0.04 μM. This particulate activity was negatively correlated with the DIP, DOP and TDP concentrations when the activities were related to the seawater volume, chlorophyll a or the protein concentration. The TDP correlations were highly significant (p: 0.001). The DOP correlations were significant (p: 0.04) and became highly significant (p: 0.009) at low DIP concentrations (<0.13 μM). The DIP correlations were significant (p: 0.04) only at low DOP concentrations (<0.18 μM). Thus, the effects of seawater DIP and DOP were found to be linked. The soluble activity exhibited distinct phosphatase fractions with high (0.5–29.5 μM) and low (0.02–2 μM) Km values, but none exhibited significant correlations with phosphorus compounds.     

Effects of lanthanum(III) and EDTA on the growth and competition of Microcystis aeruginosa and Scenedesmus quadricauda

Rare earth elements (REEs) are widely used to increase crop production in China. However, little attention has been paid to their impacts on aquatic ecology. Batch cultivation was used here to study the effects of lanthanum (La) and EDTA on the growth and competition of the cyanobacterium Microcystis aeruginosa and the green alga Scenedesmus quadricauda. When EDTA was present at a very low concentration (0.269 μmol L⁻¹), low lanthanum concentrations (?7.2 μmol L⁻¹) had little stimulative effect on the growth of M. aeruginosa and S. quadricauda, whereas a high lanthanum concentration (72 μmol L⁻¹) had significant inhibitory effect on both of them. The results of cultivation experiments suggested that the inhibitory effect on M. aeruginosa was higher than that on S. quadricauda and S. quadricauda could become dominant in mixed cultures. When lanthanum was not added to the culture medium, high EDTA concentrations (>13.4 μmol L⁻¹) had a great inhibitory effect on the growth of M. aeruginosa but little effect on the growth of S. quadricauda, which could become dominant in the mixed cultures.Lanthanum and EDTA had complex effects on the growth and competition of M. aeruginosa and S. quadricauda. EDTA did not change the stimulation of low lanthanum concentrations on both, but at intermediated concentrations (2.69-13.4 μmol L⁻¹) it could greatly alleviate lanthanum inhibition on M. aeruginosa; thus, M. aeruginosa would dominate S. quadricauda in these mixed cultures. Lanthanum at low concentration (7.2 μmol L⁻¹) could also alleviate the inhibition of high EDTA on M. aeruginosa, but did not alter the outcome of the competition.     

Selenium and mercury concentrations in harbor seals (Phoca vitulina) from central California: Health implications in an urbanized estuary

We measured total selenium and total mercury concentrations ([TSe] and [THg]) in hair (n = 138) and blood (n = 73) of harbor seals (Phoca vitulina) from California to assess variation by geography and sex, and inferred feeding relationships based on carbon, nitrogen, and sulfur stable isotopes. Harbor seals from Hg-contaminated sites had significantly greater [THg], and lesser [TSe] and TSe:THg molar ratios than seals from a relatively uncontaminated site. Males had significantly greater [THg] than females at all locations. Sulfur stable isotope values explained approximately 25% of the variability in [THg], indicating increased Hg exposure for seals with a greater use of estuarine prey species. Decreased [TSe] in harbor seals from Hg-contaminated regions may indicate a relative Se deficiency to mitigate the toxic effects of Hg. Further investigation into the Se status and the potential negative impact of Hg on harbor seals from Hg-contaminated sites is warranted.     

Occurrence and levels of polybrominated diphenyl ethers (PBDEs) in recent sediments and marine organisms from Xiamen offshore areas, China

Surface sediments and porewater from 12 sites within Xiamen offshore areas and organisms from a heavily contaminated site Yuandang Lagoon were sampled and analyzed for eight polybrominated diphenyl ethers (PBDEs) congeners (-28, -47, -99, -100, -153, -154, -183 and -209). The total concentrations of eight PBDEs (∑₈PBDEs) and BDE-209 in sediments ranged from 0.27 to 76.54 ng/g with an average of 16.31 ng/g and from 0.10 to 70.11 ng/g with an average of 14.94 ng/g, respectively. Concentrations of ∑₈PBDEs in porewater ranged from 2.5 to 34.1 ng/L, with a mean value of 15.3 ng/L. In this study, the partition coefficients (log ) of PBDE congeners (without -209) were significantly correlated with their octanol-water partition coefficients (log K_OW) (r² = 0.74, P < 0.01). ∑₈PBDE concentrations ranged from 0.33 to 1.26 ng/g (lipid weight) in marine organisms, and PBDE congener patterns were significantly different between fish and clam, crab.     

PBDEs, methoxylated PBDEs and HBCDs in Japanese common squid (Todarodes pacificus) from Korean offshore waters

Little information is available on the levels of brominated compounds found in biota from the Korean Peninsula. In this study, Japanese common squids (Todarodes pacificus) were analyzed for 38 polybrominated diphenyl ethers, two methoxylated polybrominated diphenyl ethers and three stereoisomers of hexabromocyclododecane (α, β, and γ-HBCD) from the east and western coasts of the Korean Peninsula. Among 38 PBDEs, 10 PBDEs were detected and their total concentrations ranged from 21 to 292 ng/g lipid wt with a mean concentration of 108 ng/g lipid wt, while two MeO-BDEs and three isomers of HBCDs were detected in all samples. BDE47 showed the highest residual level, followed by BDE99, 154, 153, 28/33. Concentrations of PBDEs and MeO-BDEs were not significantly different between the both sides of the Korean Peninsula; however, HBCD concentrations were higher levels in the East/Japan Sea than the Yellow Sea, indicating that HBCD sources possibly exist in Japan.     

Biological,physical and chemical properties at the Subtropical Shelf Front Zone in the SW Atlantic Continental Shelf

The physical aspects of the Subtropical Shelf Front (STSF) for the Southwest Atlantic Continental Shelf were previously described. However, only scarce data on the biology of the front is available in the literature. The main goal of this paper is to describe the physical, chemical and biological properties of the STSF found in winter 2003 and summer 2004. A cross-section was established at the historically determined location of the STSF. Nine stations were sampled in winter and seven in summer. Each section included a series of conductivity-temperature-depth (CTD) stations where water samples from selected depths were filtered for nutrient determination. Surface samples were taken for chlorophyll a (Chl-a) determination and plankton net tows carried out above and below the pycnocline. Results revealed that winter was marked by an inner-shelf salinity front and that the STSF was located on the mid-shelf. The low salinity waters in the inner-shelf indicated a strong influence of freshwater, with high silicate (72 μM), suspended matter (45 mg l⁻¹), phosphate (2.70 μM) and low nitrate (1.0 μM) levels. Total dissolved nitrogen was relatively high (22.98 μM), probably due to the elevated levels of organic compound contribution close to the continental margin. Surface Chl-a concentration decreased from coastal well-mixed waters, where values up to 8.0 mg m⁻³ were registered, to offshore waters. Towards the open ocean, high subsurface nutrients values were observed, probably associated to South Atlantic Central Waters (SACW). Zooplankton and ichthyoplankton abundance followed the same trend; three different groups associated to the inner-, mid- and outer-shelf region were identified. During summer, diluted waters extended over the shelf to join the STSF in the upper layer; the concentration of inorganic nutrients decreased in shallow waters; however, high values were observed between 40 and 60 m and in deep offshore waters. Surface Chl-a ranged 0.07–1.5 mg m⁻³; winter levels were higher. Three groups of zoo and ichthyoplankton, separated by the STSF, were also identified. Results of the study performed suggest that the influence of freshwater was stronger during winter and that abundance distribution of Chl-a, copepods and ichthyoplankton was related to the Plata Plume Waters (PPW), rather than to the presence of the STSF. During summer, when the presence of freshwater decreases, plankton interactions seem to take place in the STSF.     

Polybrominated diphenyl ethers do not affect metamorphosis but alter the proteome of the invasive slipper limpet Crepidula onyx

Man-made polybrominated diphenyl ethers (PBDEs) used as flame retardants in various consumer products may be harmful to marine organisms. Larvae of some marine invertebrates, especially invasive species, can develop resistance to PBDEs through altered protein expression patterns or proteome plasticity. This is the first report of a proteomics approach to study BDE-47 induced molecular changes in the invasive limpet Crepidula onyx. Larvae of C. onyx were cultured for 5 days (hatching to metamorphosis) in the presence of BDE-47 (1 μg L⁻¹). Using a 2-DE proteomics approach with triple quadrupole and high-resolution TOF-MS, we showed that BDE-47 altered the proteome structure but not the growth or metamorphosis of C. onyx larvae. We found eight significant differentially expressed proteins in response to BDE-47, deemed the protein expression signature, consisting of cytoskeletal, stress tolerance, metabolism and energy production related proteins. Our data suggest C. onyx larvae have adequate proteome plasticity to tolerate BDE-47 toxicity.     

Organohalogen contaminants in striped dolphins (Stenella coeruleoalba) from Japan: Present contamination status, body distribution and temporal trends (1978-2003)

Organohalogen contaminants including PCBs, DDTs, CHLs, HCHs, HCB, PBDEs and HBCDs were determined in striped dolphins (Stenella coeruleoalba) found stranded at Gogo-shima (n = 6, 2003) and collected from Taiji (n = 15, 1978-1992) in Japan. All target compounds were significantly detected in all the specimens, indicating ubiquitous contamination of oceanic cetaceans in northwest Pacific Ocean. Examination of body distribution of organohalogens in the six specimens from Gogo-shima showed no significant difference in concentrations among the analyzed tissues, except for brain, which had lower levels possibly due to the existence of blood-brain barrier. For evaluating temporal trends, archived blubber samples of adult male stripped dolphins collected in 1978, 1979, 1986 and 1992 were analyzed. Concentrations of PCBs, DDTs and HCHs did not change significantly during 1978-2003. In contrast, remarkable increasing trends of PBDEs and HBCDs were observed, suggesting growing consumption in Japan and surrounding countries in recent years.     

Brominated flame retardants and organochlorine contaminants in winter flounder, harp and hooded seals, and North Atlantic right whales from the Northwest Atlantic Ocean

Various brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and current-use, non-PBDE BFRs, as well as organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs), were measured in winter flounder, harp and hooded seals, and North Atlantic right whales from the Eastern United States and Canada. The concentrations of PBDEs in winter flounder and right whales were similar in magnitude to the levels of PCBs, which was unlike the pattern observed in seals. In these marine mammals, the levels of PBDEs were orders of magnitude lower than the levels of OCs and PCBs detected. Evidence existed for the accumulation of methoxylated (MeO)-PBDEs of natural origin in seals and right whales. Current-use, non-PBDE BFRs (including hexabromocyclododecane, pentabromoethylbenzene, hexabromobenzene, and pentabromotoluene) were detected in winter flounder and marine mammals. Future research should focus on monitoring PBDEs, current-use, non-PBDE BFRs, and MeO-BDEs of natural origin in marine organisms from Massachusetts and Cape Cod Bays.     

Bioconcentration and biomagnification of polybrominated diphenyl ethers (PBDEs) through lower-trophic-level coastal marine food web

Bivalves, crabs, fishes, seawater, and sediment collected from the inner part of Tokyo Bay, Japan, were measured for 20 polybrominated diphenyl ether (PBDE) and 5 polychlorinated biphenyl (PCB) congeners. To determine the trophic levels of the organisms, carbon and nitrogen stable isotope ratios (δ¹³C and δ¹⁵N) were also measured. Bioconcentration factors of PBDE and PCB congeners increased as the octanol-water partition coefficient (K_ow) rose to log K_ow = 7, above which they decreased again. Biomagnification of PCBs and several PBDE congeners (BDE47, 99, 100, 153 and 154) up the trophic ladder was confirmed by a positive correlation between their concentrations and δ¹⁵N. Other PBDE congeners showed a negative or no correlation, suggesting their biotransformation through metabolism. The more hydrophobic congeners of both PBDEs (Br = 2-6) and PCBs (Cl = 6-9) were biomagnified more. It thus appears that PBDEs are less biomagnified than PCBs.     

Effects of alumina refinery wastewater and signature metal constituents at the upper thermal tolerance of: 2. The early life stages of the coral Acropora tenuis

The success of early life history transitions of the coral Acropora tenuis were used as endpoints to evaluate thermal stress and the effects of wastewater discharged to a tropical marine environment. The studies assessed the effects of: (i) temperature; (ii) three signature metals of the wastewater, aluminium (Al), vanadium (V) and gallium (Ga); and (iii) the wastewater (at 27 °C and 32 °C) on fertilisation and larval metamorphosis. The median inhibition temperatures for fertilisation and metamorphosis were 32.8 °C and 33.0 °C, respectively. Fertilisation IC₅₀s for Al, V and Ga were 2997, 2884 and 3430 μg L⁻¹, respectively. Metamorphosis IC₅₀s for Al, V and Ga were 1945, 675 and 3566 μg L⁻¹, respectively. The wastewater only affected fertilisation and metamorphosis at moderate concentrations (IC₅₀s = 63% and 67%, v/v, respectively, at 27 °C), posing a low risk to this species in the field. The effects of wastewater and temperature on fertilisation and metamorphosis were additive.     

Eutrophication and hypoxia in four streams discharging in Guanabara Bay, RJ, Brazil, a case study

Four streams in the city of São Gonçalo, were sampled to evaluate their potential as sources of nutrients to Guanabara Bay aiming to contribute with the government program to decrease the levels of pollution in this area. Imbuaçu, Guaxindiba, Marimbondo and Brandoas streams were sampled in 2007, 2008 and 2009. The streams revealed to be hipereutrophic with severe limitation of primary production by nitrogen, as shown by the N/P molar ratio. Phosphate levels were abnormally high varying between 4.35 and 130.82 μM, whereas nitrate and nitrite ranged from 0.06 to 54.05 μM and from 0.28 to 19.23 μM, respectively. The streams also presented severe hypoxia and anoxia, with oxygen values varying from non-detected to 3.72 ml l⁻¹. Heavy loads of particulate suspended material were recorded in the studied streams, ranging between 6.00 and 400.00 mg l⁻¹. The streams were considered inexorable sources of nutrients, enhancing the severe eutrophication process in Guanabara Bay.     

Bacterioplankton dynamics along the gradient from highly eutrophic Pearl River Estuary to oligotrophic northern South China Sea in wet season: implication for anthropogenic inputs

Bacterioplankton abundance (BA) and biomass (BB) from the eutrophic Pearl River Estuary (PRE) to the oligotrophic northern South China Sea (NSCS) were studied in the wet season. BA was significantly higher (p < 0.05) in PRE (12.51 ± 3.52 × 10⁸ cells L⁻¹), than in the continental shelf neritic province (CSNP, 4.95 ± 2.21 × 10⁸ cells L⁻¹) and in the deep oceanic province (OP, 3.16 ± 1.56 × 10⁸ cells L⁻¹). Nutrient-replete PRE waters (DIN > 100 μM and PO₄ > 1 μM) resulted in high chl a and BB, whereas nutrient-depleted offshore waters (DIN <5 μM and PO₄ < 0.5 μM) had low biomass. Temperature (>26 °C) was not the controlling factor of BA. BB was significantly correlated with chl a biomass both in PRE and NSCS. The bacteria to phytoplankton biomass (BB/PB) ratio increased clearly along the gradient from near-shore PRE (0.15) to offshore CSNP (0.93) and deep OP (2.75), indicating the important role of small cells in the open ocean compared to estuarine and coastal zones.