Degradation of pentachlorophenol by pure and mixed cultures in two different soils

GOAL, SCOPE AND BACKGROUND: Pentachlorophenol (PCP) is the second highest volume pesticide used in the United States. It is a mutagenic compound whose exposure poses significant health effects, One of the most desirable, environmentally friendly treatment methods is bioremediation. For soil-based contamination, the effectiveness of bioremediation will also be affected by the presence of an active indigenous population, sorption of the contaminant onto the soil, and environmental parameters. METHODS: Two pure strains and their mixed culture were used to evaluate PCP biodegradation in two different field soils, Columbia (CO) and New Mexico (NM). Biostimulation of the indigenous microbes was evaluated by adding nutrients. The efficiency of adding bacteria strains (bioaugmentation) for degrading PCP was determined with Arthrobacter sp., Flavobacterium sp. and a 50:50 mixture of the two bacteria strains. RESULTS: In CO soil, only 24%, 12% and 25% of the initial PCP concentration were degraded by Flavobacterium sp., Arthrobacter sp. and mixed culture, respectively. Arthrobacter sp. was used in NM soil with two initial concentrations and achieved degradation efficiencies of 57% and 61% for 361 and 95 mg kg- concentrations, respectively. Discussion. Analysis via statistical methods showed that the bacteria had different efficiencies on PCP degradation in each soil. 2 CONCLUSIONS: All bacteria catalyzed a higher PCP degradation when present in NM soil. Second, Flavobacterium sp. degraded more PCP than Arthrobacter sp. in CO soil. The mixed culture achieved the highest degradation efficiency regardless of the initial concentration or soil origin. RECOMMENDATIONS AND PERSPECTIVES: The effect of the soil properties, such as the soil organic matter (SOM) on PCP biodegradation should be investigated. Future work can also investigate the effect of aging time on biodegradation.     

Carbon footprint of canned mussels from a business-to-consumer approach. A starting point for mussel processors and policy makers

The increasing demand for environmental information on the global warming impact of products requires a solid methodological framework which guarantees comparability and communicability. The publicly available specification PAS 2050 combines approaches to a variety of greenhouse gas specific assessment issues to deliver a globally applicable product Carbon Footprinting (CF) method, which is expected to be widely accepted. Specifically, this paper aims to demonstrate the implementation of a CF scheme for a common canned mussel product according to PAS 2050 guidelines. A final value of 4.35 kg CO₂e per triple pack of round cans of mussels was calculated. Furthermore, this CF study led to identify primary packaging (can production) and mussel shell management as the main activities where efforts should focus for climate change mitigation. Throughout this case study, CF opportunities and drawbacks are discussed. The whole text tries to provide a starting point for both mussel processors and policy makers to benefit from the potential advantages of a responsible use of this increasingly popular tool.     

Revisiting the Life Cycle Assessment of mussels from a sectorial perspective

Mussels as a commercial product involve a range of activities which can be included within four different sub-sectors: culture, dispatch centres, canning factories and, finally, cooking plants. This paper deals with the environmental evaluation of the whole mussel sector from a Life Cycle Assessment approach. The use of exhaustive inventories led to the subsequent environmental characterization of the mussel sector in terms of the contribution observed for each of the sub-sectors. In this sense, the sub-sector associated with dispatch centres presented the largest contributions to the potential environmental impacts, clearly ahead of mussel farming. Furthermore, the sub-sectors of mussel cooking plants and canning factories showed a much lower contribution to the potential environmental impacts. Several improvement potentials were identified from the characterization results, stressing the minimization of the electric energy consumption in dispatch centres. A comparative LCA was performed in order to contrast the environmental performance of the three main commercial mussel products: fresh mussels, canned mussels and frozen mussels. The analysis showed that fresh mussels have the least favourable environmental profile.     

Vegetable and synthetic tannins induce hormesis/toxicity in sea urchin early development and in algal growth

Mimosa tannin and phenol-based synthetic tannin (syntan) were tested for toxicity to sea urchin (Paracentrotus lividus and Sphaerechinus granularis) early development and to marine algal growth (Dunaliella tertiolecta). Sea urchin embryogenesis was affected by vegetable tannin and syntan water extracts (VTWE and STWE) at levels >or=1mg/L. Developmental defects were significantly decreased at VTWE and STWE levels of 0.1 and 0.3mg/L when control cultures displayed suboptimal quality, i.e. <70% "viable" (normal or retarded) larvae. Fertilization success of sea urchin sperm was increased up to 0.3 mg/L STWE or VTWE, then was inhibited by increasing tannin levels (1-30 mg/L). Offspring abnormalities, following sperm exposure to VTWE or STWE, showed the same shift from hormesis to toxicity. Cell growth bioassays in D. tertiolecta exposed to VTWE or STWE (0.1-30 mg/L) showed non-linear concentration-related toxicity. Novel criteria are suggested in defining control quality that should reveal hormetic effects.     

XAFS studies of cobalt(II) binding by solid peat and soil-derived humic acids and plant-derived humic acid-like substances

This work has examined cobalt(II) binding by a variety of solid humic acids (HAs) isolated from peat, plant and soil sources at temperatures down to 60K. The results confirm that X-ray absorption near-edge spectroscopy (XANES) measurements cannot distinguish between aquo and carboxylato ligands in the inner coordination sphere of Co(II). However, between 1 and 2 inner-sphere carboxylato ligands can be detected in all the peat, plant and soil-derived HA samples by extended X-ray absorption fine structure (EXAFS) measurements, indicating inner-sphere coordination of HA-bound Co(II). The precision of C(carboxylate) detection is limited by the extent and quality of the data and the contribution from inner-sphere O to the Fourier transformed peaks used to detect carbon. Putative chelate ring formation is consistent with a relatively negative entropy change in step A, the stronger Co(II) binding step by HA functional groups, and could relate to 'non-exchangeable' metal binding by HSs.     

A system-based approach to the genetic etiologies of non-immune hydrops fetalis

A wide spectrum of genetic causes may lead to nonimmune hydrops fetalis (NIHF), and a thorough phenotypic and genetic evaluation are essential to determine the underlying etiology, optimally manage these pregnancies, and inform discussions about anticipated prognosis. In this review, we outline the known genetic etiologies of NIHF by fetal organ system affected, and provide a systematic approach to the evaluation of NIHF. Some of the underlying genetic disorders are associated with characteristic phenotypic features that may be seen on prenatal ultrasound, such as hepatomegaly with lysosomal storage disorders, hyperechoic kidneys with congenital nephrosis, or pulmonary valve stenosis with RASopathies. However, this is not always the case, and the approach to evaluation must include prenatal ultrasound findings as well as genetic testing and many other factors. Genetic testing that has been utilized for NIHF ranges from standard chromosomal microarray or karyotype to gene panels and broad approaches such as whole exome sequencing. Family and obstetric history, as well as pathology examination, can yield additional clues that are helpful in establishing a diagnosis. A systematic approach to evaluation can guide a more targeted approach to genetic evaluation, diagnosis, and management of NIHF.     

Passive sampling: partition coefficients for a silicone rubber reference phase

Silicone rubber sheeting can be used as a passive sampling device for hydrophobic organic contaminants in the environment to determine the available concentrations in water and sediments. Reliable sampler-water partition coefficients are required to determine the sampling rates and the dissolved contaminant concentrations in water and in sediment pore water. Log partition coefficients (logK(sr,w)) for silicone rubber-water have been estimated for 32 polycyclic aromatic hydrocarbons (PAHs), 2 deuterated PAH analogues and 32 chlorobiphenyls (CBs) using the cosolvent method, with methanol as cosolvent. Strong linear relationships were found with literature values for the corresponding log octanol-water partition coefficients (logK(ow)) for both CBs and PAHs, confirming that partitioning into the silicone rubber is strongly determined by the hydrophobicity of the compounds, which suggests logK(ow) is a good predictor of logK(sr,w) and that absorption is the main mechanism for accumulation of analytes into the silicone rubber polymer.     

Effect of fly ash addition on the removal of hydrogen sulfide from biogas and air on sewage sludge-based composite adsorbents

Desulfurization adsorbents were prepared from the mixtures of various compositions of New York City sewage sludge and fly ashes from SASOL, South Africa, by pyrolysis at 950 degrees C. The resulting materials were used as adsorbents of hydrogen sulfide from simulated dry digester gas mixture or moist air. The adsorbents before and after H(2)S removal were characterized using adsorption of nitrogen, elemental analysis, pH measurements, XRF, XRD, and thermal analysis. It was found that the addition of fly ash decreases the desulfurization capacity in comparison with the sewage sludge-based materials. The extent of this decrease depends on the type of ash, its content and the composition of challenging gas. Although the presence of CO(2) deactivates some adsorption sites to various degrees depending on the sample composition, the addition of ashes has a more detrimental effect when the adsorbents are used to remove hydrogen sulfide from air. This is likely the result of hydrophobicity of ashes since the H(2)S removal capacity was found to be strongly dependent on the reactivity towards water/water adsorption. On the other hand, the addition of ashes strongly decreases the porosity of materials where sulfur, as a product of hydrogen sulfide oxidation, can be stored.