Physical-chemical characterization and leaching studies involving drill cuttings generated in oil and gas pre-salt drilling activities.

This work describes characterization and leaching studies of pre-salt drill cuttings from offshore oil and gas exploration in ultradeep waters. The metals Fe, Al, and Ba were present in the highest concentrations in drill cuttings (30000 mg kg-1, 32600 mg kg-1, and 33000 mg kg-1 respectively). The most significant contents of Ba, Al, Fe, Cu, Pb, Mn, Si, and Zn were found in cuttings containing non-aqueous fluids (NADF), but the highest concentrations of Ni and Cr were found in samples containing aqueous fluids (WBDF). The content of total petroleum hydrocarbons (TPHs) in the samples with WBDF fluids ranged from < 5.58 to 15.76 mg Kg-1 while the TPH content of the samples with NADF ranged from 28.46 to 47.16 mg Kg-1. Data on the content of unresolved complex mixtures (UCMs) and sheen tests indicated probable contamination of some cutting samples with oil. Most samples showed some degree of contamination by polycyclic aromatic hydrocarbons (PAHs). The metals present in the highest concentrations in saline and aqueous leachates were Si and Ba. The metals Cd, Cu, Ni, and Zn were present in varied concentrations in the saline leachates, and the metals Si, Ba, Cu, and Zn were found in the aqueous leachates.

Effects of untreated and treated oilfield-produced water on seed germination, seedling development, and biomass production of sunflower (Helianthus annuus L.).

This study aims to evaluate possible toxic effects of oil and other contaminants from oilfield-produced water from oil exploration and production, on seed germination, and seedling development of sunflower (Helianthus annuus L.). In comparison, as treated by electroflocculation, oilfield-produced water, with lower oil and organic matter content, was also used. Electroflocculation treatment of oilfield-produced water achieved significant removals of chemical oxygen demand (COD) (94 %), oil and grease (O&G) (96 %), color (97 %), and turbidity (99 %). Different O&G, COD, and salt levels of untreated and treated oilfield-produced water did not influence germination process and seedling biomass production. Normal seedlings percentage and vigor tended to decrease more intensely in O&G and COD levels, higher than 337.5 mg L(-1) and 1321 mg O2 L(-1), respectively, using untreated oilfield-produced water. These results indicate that this industrial effluent must be treated, in order to not affect adversely seedling development. This way, electroflocculation treatment appears as an interesting alternative to removing oil and soluble organic matter in excess from oilfield-produced water improving sunflower's seedling development and providing a friendly environmental destination for this wastewater, reducing its potential to harm water resources, soil, and biota.

Enhanced diesel fuel fraction from waste high-density polyethylene and heavy gas oil pyrolysis using factorial design methodology.

Factorial Design Methodology (FDM) was developed to enhance diesel fuel fraction (C9-C23) from waste high-density polyethylene (HDPE) and Heavy Gas Oil (HGO) through co-pyrolysis. FDM was used for optimization of the following reaction parameters: temperature, catalyst and HDPE amounts. The HGO amount was constant (2.00 g) in all experiments. The model optimum conditions were determined to be temperature of 550 °C, HDPE = 0.20 g and no FCC catalyst. Under such conditions, 94% of pyrolytic oil was recovered, of which diesel fuel fraction was 93% (87% diesel fuel fraction yield), no residue was produced and 6% of noncondensable gaseous/volatile fraction was obtained. Seeking to reduce the cost due to high process temperatures, the impact of using higher catalyst content (25%) with a lower temperature (500 °C) was investigated. Under these conditions, 88% of pyrolytic oil was recovered (diesel fuel fraction yield was also 87%) as well as 12% of the noncondensable gaseous/volatile fraction. No waste was produced in these conditions, being an environmentally friendly approach for recycling the waste plastic. This paper demonstrated the usefulness of using FDM to predict and to optimize diesel fuel fraction yield with a great reduction in the number of experiments.

Selecting a sensitive battery of bioassays to detect toxic effects of metals in effluents.

The use of bioassay batteries is necessary to evaluate toxic effects at various biological levels. The selection of bioassays without prior testing and determination of the most sensitive/suitable groups for each impact may allow the discharge of effluents that pose a threat to the environment. The present study tested and selected a battery of sensitive ecotoxicological bioassays for detecting toxic effects of metals. The sensitivities of six organisms were evaluated (algae Pseudokirchneriella subcapitata and Chlorella vulgaris, Cladocera Daphnia similis and Ceriodaphnia dubia, and fish Poecilia reticulata and Danio rerio) after exposure to 10 individual metal species deemed toxic to the aquatic environment (Ag+, Cd2+, Cu+, Cu2+, Cr3+, Cr6+, Pb2+, Ni2+, Zn2+, and Hg2+) and to real (steel-mill) and laboratory simulated effluents. In the bioassays, fish were the least sensitive; D. rerio showed no sensitivity to any of the effluents tested. P. subcapitata was a good bioindicator of Cr3+ toxicity, and D. similis was the most sensitive organism to Hg2+; but the toxic effect of effluents with higher levels of Hg2+ was better detected by C. dubia. The most sensitive battery of bioassays to detect low concentrations of dissolved metals in effluents was the 72-h chronic test with C. vulgaris and the 48-h acute test with C. dubia.

Toxicological evaluation of Euterpe edulis: a potential superfruit to be considered.

Superfruits have a high nutritional value due to their richness in nutrients, antioxidants, proven or potential health benefits and taste appeal. However, there are no scientific criteria for defining which fruits are superfruits. In Brazil, several palms have an edible palm heart, the best known and most widely appreciated of which is called Acai (Euterpe oleracea). Euterpe edulis Mart., commonly called jussara, is an evergreen species that grows in the rainforest. Having initially been consumed in the form of juice and pulp, they have since been incorporated as an ingredient in many foods. A risk assessment to identify adverse health effects is a prerequisite for taking forward the development of new drugs, cosmetics and foods. To make a toxicological evaluation of E. edulis, in the present work this prerequisite was met by an interdisciplinary network that performed mass spectroscopy analyses, blood biochemistry, genotoxicity, bacterial reverse mutation and cytotoxicity assays. Positive mutagenicity results were detected for Salmonella typhimurium TA97 at low doses, and positive results were also obtained for the mammalian erythrocyte micronucleus assay, indicating that the pulp of E. edulis contains compounds with the capacity to induce mutagenicity and clastogenic/aneugenic effects.