Toxicological responses in Laeonereis acuta (annelida, polychaeta) after arsenic exposure

Several environmental pollutants, including metals, can induce oxidative stress. So, the objective of this study was to evaluate the effects of arsenic (As(III), as As(2)O(3)) on the antioxidant responses in the polychaete Laeonereis acuta. Worms were exposed to two environmentally relevant concentrations of As, including the highest previously allowed by Brazilian legislation (50 microg As/l). A control group was kept in saline water (10 per thousand) without added metal. It was observed that: (1) a peak concentration of lipid peroxide was registered after 2 days of exposure to 50 microg As/l (61+/-3.2 nmol CHP/g wet weight) compared to the control group (43+/-4.5 nmol CHP/g wet weight), together with a lowering of the activity of the antioxidant enzyme catalase (-47 and -48%, at 50 or 500 microg As/l respectively) and a higher superoxide dismutase activity (+305% at 50 microg As/l with respect to the control group); (2) a lower conjugation capacity through glutathione-S-transferase activity was observed after 7 days of exposure to 50 microg As/l (-48% compared to the control group); (3) a significant increase in As concentration was verified after 1 week of exposure to both As concentrations (50 and 500 microg/l); (4) worms exposed to As showed a limited accumulation of related methylated As species and the levels of non-toxic As species like arsenobetaine (AsB) and arsenocholine (AsC) remained unchanged during the exposure period when compared with the controls. Overall, it can be concluded that As interfered in the antioxidant defense system of L. acuta, even at low concentrations (50 microg/l) that Brazilian legislation previously considered safe. The fact that worms exposed to As showed high levels of methylated As species indicates the methylation capability of L. acuta, although the high levels of inorganic As suggest that not all the administered As(III) (as As(2)O(3)) is completely removed or biotransformed after 7 days of exposure.     

Absorption and translocation of sulfometuron-methyl in sugarcane (Saccharum officinarum L.) at different growth stages

ABSTRACT

In Brazil, weed management in sugarcane fields is mainly done with the use of selective herbicide formulations. For many years, diuron+hexazinone was one of the main herbicide mixture formulations used in sugarcane. Later, sulfometuron-methyl was included in the same mixture, which was marketed as a new herbicide formulation for residual in-season weed control in sugarcane. The mixture diuron+hexazinone+sulfometuron-methyl has been widely used in commercial sugarcane fields in Brazil. However, recent field observations have shown that sugarcane plants at different growth stages varied in their phytotoxicity levels after treatment with diuron+hexazinone+sulfometuron-methyl. Greenhouse and laboratory studies were conducted to determine ¹⁴Csulfometuron-methyl absorption and translocation, as well as ¹⁴C distribution in sugarcane at two growth stages, 2 to 3 leaves and 5 to 6 leaves. ¹⁴Csulfometuron-methyl absorption by sugarcane did not differ between the two growth stages. Different patterns of ¹⁴C accumulation were observed, which may explain variations in sulfometuron-methyl phytotoxic responses observed in the field.     

On the importance of size of plastic fragments and pellets on the strandline: a snapshot of a Brazilian beach

Virgin plastic pellets and plastic fragments are reported as ubiquitous beach contaminants in the peer-reviewed literature. A surface density of 0.3 virgin plastic pellets and plastic fragments per square centimeter of the strandline area was registered on an urban beach of the northeast of Brazil. This beach is presently not affected by petrochemical facilities or pellet processing plants. The main source of fragments (96.7%) was attributed to the breaking down of larger plastic items deposited on the beach. In the case of virgin plastic pellets (3.3%), the main sources were the marine environment and possibly nearby port facilities. This category of plastic pollutant offers particular threats to the marine environment and to beach users.     

Norovirus GII.17 Associated with a Foodborne Acute Gastroenteritis Outbreak in Brazil, 2016

Foodborne transmission gastroenteritis (AGE) outbreak occurred during a celebration lunch in July, 2016, Brazil. All stool samples tested were positive for noroviruses (NoV) and phylogenetic analysis revealed that strains were genetically close to GII.17 Kawasaki_2014. These findings indicated circulation of NoV GII.17 Kawasaki_2014 in the Brazilian population, associated with AGE outbreak.     

Integrating local knowledge with science and technology in management of soil,water and nutrients: implications for management of natural capital for sustainable rural livelihoods

Harnessing local knowledge and practices for sustainable management of soil, water and nutrients is important for sustainable development. This work aims to understand soil productivity in traditional open-ridging practices and integrate scientific ideas and technologies into traditional practices for enhancing management of soil productivity. Participatory assessments, household surveys, field experiments, observations and analyses of outcomes were used. Participatory assessments revealed declining natural soil fertility and maize productivity over time, a concern reiterated by 82.5% of respondents. Evaluation of ridge tillage practices showed that bean yields were significantly (p?<?0.05) higher by 19–35% in traditional open ridges and increased by 23–38% when ties were integrated. Integration of fertilizers resulted in significantly (p?<?0.05) higher subsequent maize yields in tied ridges than in traditional open ridge and flat cultivation practices. Improved integrated tillage practices resulted in increased soil and water conservation, soil fertility and crop tolerance to prolonged no-rainfall spells. National development policies should create enabling environments for smallholder farmers to integrate modern knowledge and technologies with their traditional knowledge and practices in land management for high and sustained quality of natural capital for secure and sustainable livelihoods.     

Metals and emerging contaminants in groundwater and human health risk assessment

Environmental Science and Pollution Research - Groundwaters are normally consumed without previous treatment and therefore the monitoring of contaminants in order to guarantee its safety is...     

Contamination by chlorinated pesticides, PCBs and PBDEs in Atlantic spotted dolphin (Stenella frontalis) in western South Atlantic

Chlorinated pesticides, PCBs and PBDEs were analysed in nine blubber samples of Atlantic spotted dolphins, Stenella frontalis, incidentally captured during fishing operations in southern and southeastern Brazil between 2005 and 2007. The majority of compounds analysed were detected, suggesting widespread contamination over the region. Although the samples came from a location far from main coastal industrial areas, the results revealed an influence from such sources. Therefore, levels of PCBs (774-23 659 ng g⁻¹ lipid wt.) and PBDEs (23-1326 ng g⁻¹ lipid wt.) detected seem to be related to the movement of individuals throughout near-shore and offshore waters. The sample from a lactating female exhibited a lower level of contamination and a distinct pattern, indicating selective transfer favouring less lipophilic compounds.     

Addition of Saturated Fatty Acids to Biodegradable Films: Effect on the Crystallinity and Viscoelastic Characteristics

Biodegradable films were produced by extrusion from blends of starch, glycerol and poly(butylene adipate co-terephthalate), a biodegradable polyester, with the addition of 1.5 % (wt/wt) saturated fatty acids (caproic, lauric or stearic). Films containing fatty acids had higher crystallinity than control films and the longer the carbon chain of the acid was, the more crystalline the film. Fatty acids with up to 12 carbon atoms did not alter the viscoelastic characteristic of the films. Further, the incorporation of fatty acids did not decrease the hydrophilicity of the films in comparison with the control film without a fatty acid.     

Marine debris contamination along undeveloped tropical beaches from northeast Brazil

We hypothesize that floating debris leaving polluted coastal bays accumulate on nearby pristine beaches. We examined composition, quantities and distribution of marine debris along approximately 150 km of relatively undeveloped, tropical beaches in Costa do Dendê (Bahia, Brazil). The study site is located south of Salvador City, the largest urban settlement from NE Brazil. Strong spatial variations were observed. Plastics accounted for 76% of the sampled items, followed by styrofoam (14%). Small plastic fragments resultant from the breakdown of larger items are ubiquitous all over the area. Because the dominant littoral drift in Bahia is southward, average beach debris densities (9.1 items/m) along Costa do Dendê were threefold higher than densities previously observed north of Salvador City. River-dominated and stable beaches had higher debris quantities than unstable, erosional beaches. Areas immediately south of the major regional embayments (Camamu and Todos os Santos) were the preferential accumulation sites, indicating that rivers draining populous areas are the major source of debris to the study site. Our results provide baseline information for future assessments. Management actions should focus on input prevention at the hydrographic basin level rather than on cleaning services on beaches.