Abundance, composition, and distribution of microplastics in intertidal sediment and soft tissues of four species of Bivalvia from Southeast Brazilian urban beaches.

In coastal areas, microplastics (MPs) can deposit in sediment, allowing it to be ingested by benthic organisms, like mussels, thus creating a possible transfer to humans. The aim of this study is to evaluate MPs pollution in sediment as a function of shoreline elevation in two urbanized beaches and to evaluate the abundance/frequency of MPs in 4 different species of bivalves commonly used in the human diet, such as the oyster Crassostrea brasiliana, the mussels Mytella strigata and Perna perna and the clam Tivela mactroides, and identify the polymers via µ-FTIR technique. A total of 3337 MPs were found in this study, of which 1488 were found in the sediment at the five sites analyzed, and 1849 in the bivalve tissues at the two sampling sites. MPs contamination was observed in all sediment samples and species of the pool and in each of the 10 specimens of the four species. Thus, the frequency of contamination by MPs reached 100 % for the analyzed samples. The number of filaments is higher than fragments in sediment samples and in each bivalve species. Regarding types and colors, the blue were greater than fragment-type in sediments and samples. In an effort to classify the polymers via µ-FTIR, our study was able to identify polypropylene, polyethylene and polyethylene terephthalate, besides a great number of cellulose fibers.

Toxicological interactions of silver nanoparticles and organochlorine pesticides in mouse peritoneal macrophages.

Nanotechnology occupies a prominent space in economy and science due to the beneficial properties of nanomaterials. However, nanoparticles may pose risks to living organisms due to their adsorption and pro-oxidative properties. The aim of the current study was to investigate the effects of polymer-coated silver nanoparticles (AgNPs) and organochlorine pesticides (OCPs), as well as their combined effects on mouse peritoneal macrophages. Macrophages were isolated and exposed to three concentrations of AgNPs (groups: N1 = 30, N2 = 300 and N3 = 3000 ng.ml(-1)), two concentrations of OCPs (groups: P1 = 30 and P2 = 300 ng.ml(-1)) and the six possible combinations of these two contaminants for 24 h. AgNPs had irregular shape, Feret diameter of 8.7 ± 7.5 nm and zeta potential of -28.7 ± 3.9 mV in water and -10.7 ± 1.04 mV in culture medium. OCP mixtures and the lower concentrations of AgNPs had no detectable effects on cell parameters, but the highest AgNPs concentration showed high toxicity (trypan blue and MTT assays) resulting in morphological changes, increase of nitric oxide levels and phagocytic index. Foremost, the association of N3 and P2 led to distinct effects from those observed under single exposure.

Heavy metals in sediments and soft tissues of the Antarctic clam Laternula elliptica: more evidence as a possible biomonitor of coastal marine pollution at high latitudes?

Studies on metal contamination in 25 de Mayo Island, Antarctica, yielded controversial results. In this work, we analyzed Antarctic marine sediments and Antarctic clam (Laternula elliptica) tissues to investigate the possible use of this mollusk as a biomonitor of metals and to identify the sources of metal pollution. Different types of paint from several buildings from Carlini Station were examined to assess their contribution to the local and random metal pollution. Five sediment samples, 105 L. elliptica specimens (40.2-78.0mm length) and four types of paint were analyzed to quantify Cd, Cr, Cu, Fe, Mn, Pb and Zn using inductively coupled plasma-optical emission spectrometry. Metal concentrations in sediments were lower than the global averages of the earth's crust, with the exception of Cd and Cu. These results were related to the contribution of the local fresh-water runoff. The different varieties of paint showed low levels of Cu, Mn, Fe and Zn, whereas a broad range of values were found in the case of Cr and Pb (20-15,100 µg·g(-1) and 153-115,500 µg·g(-1) respectively). The remains of the paint would be responsible for the significant increases in Cr and Pb which are randomly detected by us and by other authors. High levels of Fe and Cd, in comparison to other Antarctic areas, appear to be related to the terrigenous materials transported by the local streams. Accumulation indexes suggested that kidney tissue from L. elliptica could be an adequate material for biomonitoring pollution with Cd, Zn and probably also Pb. In general, relationships between size and metal contents reported by other authors were not verified, suggesting that this issue should be revised.

Complex metabolic interactions between benzo(a)pyrene and tributyltin in presence of dichlorodiphenyltrichloroethane in South American catfish Rhamdia quelen.

In an attempt to explore complex metabolic interactions between toxicants present in polluted freshwater, hepatic metabolism of benzo(a)pyrene (BaP) and tributyltin (TBT) in fish was investigated when these compounds were administrated alone, mixed together and along with dichlorodiphenyltrichloroethane (DDT). Ten Rhamdia quelen per group were treated with a single intra-peritoneal (IP) dose (5-day experiment) or three successive doses (15-day experiment) either containing BaP (0.3; 3 or 30mgkg(-1)) or TBT (0.03; 0.3 or 3mgkg(-1)) or a combination of BaP+TBT, BaP+DDT, TBT+DDT and BaP+TBT+DDT under their respective lower doses, with DDT dose kept at 0.03mgkg(-1). Tetrahydroxy-benzo(a)pyrene (BaP-tetrol-I), and dibutyltin (DBT) and monobutyltin (MBT) were analyzed to assess BaP and TBT hepatic metabolism, respectively. A significant difference in BaP-tetrol-I concentration was observed in liver and bile between the lowest and the highest doses of BaP in both 5 and 15-day experiments. In the 15-day experiment, the presence of TBT with BaP reduced the amount of BaP-tetrol-I in bile compared to the BaP alone. The time of exposure and the number of doses affected BaP-tetrol-I concentration in the bile of fish exposed to BaP 0.3mgkg(-1) and BaP+DDT. TBT and its metabolites concentrations showed a dose-dependent increase in the liver in both experiments and in the bile in the 5-day experiment. TBT at its lowest dose was completely metabolized into DBT and MBT in the liver in the 15-day experiment. No TBT metabolites were detected in the bile of fish exposed to the mixtures in the 5-day experiment, except for a small MBT amount found in BaP+TBT+DDT. This study strengthens the hypothesis of a metabolic interaction between BaP and TBT in fish and suggests DDT as an important third player when present in the mixture.

Presence and distribution of persistent toxic substances in sediments and marine organisms of Potter Cove, Antarctica.

Levels of butyltin compounds, polychlorinated biphenyls, and heavy metals were analyzed in marine sediments and organisms (Notothenia coriiceps, Laternula elliptica, and Nacella concinna), each of which has a different feeding strategy, in Potter Cove, Antarctica. PCBs were lower than detection limits in all samples. Only butyltin compounds were detected in a restricted area near the scientific station. Chromium, copper, magnesium, lead (Pb), and zinc had similar behavior in the cove, probably because they are regulated by similar process and conditions. However, Pb levels in some sites of the cove seem to be related to human activities in the area. Cadmium levels were relatively low, with the highest values found close to the shoreline, which is probably influenced by seasonal streams draining waters from Potter Peninsula. Results showed that despite the fact that Jubany Station has been operating for > 50 years, surface sediment and biota from Potter Cove do not exhibit levels of pollutants representing environmental concern.

Polycyclic aromatic hydrocarbons in soil and surface marine sediment near Jubany Station (Antarctica). Role of permafrost as a low-permeability barrier.

Although Antarctica is still considered as one of the most pristine areas of the world, the growing tourist and fisheries activities as well as scientific operations and their related logistic support are responsible for an increasing level of pollutants in this fragile environment. Soils and coastal sediments are significantly affected near scientific stations particularly by polycyclic aromatic hydrocarbons (PAHs). In this work sediment and soil were sampled in two consecutive summer Antarctic expeditions at Potter Cove and peninsula, in the vicinity of Jubany Station (South Shetland Islands). Two- and 3-ring PAHs (methylnaphthalene, fluorene, phenanthrene and anthracene) were the main compounds found in most sites, although total PAH concentrations showed relatively low levels compared with other human-impacted areas in Antarctica. Pattern distribution of PAHs observed in samples suggested that low-temperature combustion processes such as diesel motor combustion and open-field garbage burning are the main sources of these compounds. An increase in PAH concentrations was observed from surface to depth into the active soil layer except for a unique sampling site where a fuel spill had been recently reported and where an inverted PAH concentration gradient was observed. The highest level was detected in the upper layer of permafrost followed by a sharp decrease in depth, showing this layer is acting as a barrier for downward PAH migration. When PAH levels in soil from both sampling programs were compared a significant decrease (p<0.01) was observed in summer 2005 (range at 75-cm depth: 12+/-1-153+/-22 ng/g) compared to summer 2004 (range at 75-cm depth: 162+/-15-1182+/-113 ng/g) whereas concentrations in surface sediment collected nearby the station PAHs increased drastically in 2005 (range: 36+/-3-1908+/-114 ng/g) compared to 2004 (range: 28+/-3-312+/-24 ng/g). Precipitation regime and water run off suggest that an important wash out of soil-PAHs occurred during the interval time between samplings. Results showed that the present PAH contamination level of Jubany Station is relatively low compared to other reported cases in Antarctica but also suggests that an increase in rain and in thawing processes caused by the global warming could result in an important soil-associated PAH mobilization with unpredictable consequences for the biota of Potter Cove.

Enzymatic inhibition and morphological changes in Hoplias malabaricus from dietary exposure to lead(II) or methylmercury.

Neotropical fish traíra (Hoplias malabaricus) were used to investigate the effects of dietary doses of metals through individual exposures to either inorganic lead(II) or methylmercury, respectively, 21 microg Pb2+g(-1) w.w. and 75 ng H(3)C-Hg+g(-1) w.w., every 5 days, for 70 days (14 doses). The erythrocyte delta-aminolevulinic acid dehydratase (ALAd) activity was inhibited after 14 doses of Pb2+ and H(3)C-Hg+. The muscle cholinesterase (ChE) activity was inhibited after 14 doses of H(3)C-Hg+. Damage in cytoskeleton and nuclei were observed after exposure to inorganic lead. Individuals exposed to H(3)C-Hg+ showed the presence of atypical granules and vesicles, cytoplasm disorganization, and mitochondria damages in hepatocytes also after 14 doses. The present results demonstrate that erythrocyte ALAd and muscle ChE activities can be used as long-term biomarkers of sublethal, subchronic, and trophic exposures to Pb2+, and H(3)C-Hg+ in fish. Also the morphological aspects described in the present work confirm the toxicity of both studied metals.

Genetic damage induced by trophic doses of lead in the neotropical fish Hoplias malabaricus (Characiformes, Erythrinidae) as revealed by the comet assay and chromosomal aberrations

The effects of clastogenic or mutagenic agents have rarely been studied in neotropical fish species exposed to contaminated water. In this study, the genetic damage caused by lead in the widely distributed South American fish, Hoplias malabaricus, was assessed using the comet (SCGE) assay and by testing for chromosomal aberrations. Eighteen specimens were acclimatized to laboratory conditions and then chronically exposed to contaminated food by feeding prey (Cyprinus sp.) injected intraperitoneally with doses of inorganic lead adjusted to give a contamination level of 21 mg of Pb2+.g-1 net weight of H. malabaricus. Three fish were sampled for chromosomal analysis after four doses (18 days) and another three after eight doses (41 days) of lead and the results then compared with three untreated controls kept under lead-free conditions. An additional six treated fish and three controls were sampled for the comet assay after 13 doses (64 days). Exposure to lead significantly increased the frequency of chromosomal aberrations and the frequency of tailed cell nuclei, the latter indicating DNA damage. These results show that H. malabaricus is a useful biological model for screening the clastogenic effects of lead and possibly other xenobiotics. The genetic damage seen here illustrates the need to investigate the potential effects of heavy metals on fish species in South America.