Transformation of erythromycin during secondary effluent soil aquifer recharging: Removal contribution and degradation path

Erythromycin (ERY), a widely used antibiotic, has recently been detected in municipal secondary effluents and poses serious threats to human health during wastewater reusing. In this study, the removal, fate, and degradation pathway of ERY in secondary effluent during soil aquifer treatment was evaluated via laboratory-scale SAT tests. Up to a 92.9% reduction of ERY in synthetic secondary effluent was observed in 1.0 m depth column system, which decreased to 64.7% when recharged with wastewater treatment plant secondary effluent. XRD-fractionation results demonstrated that the transphilic acid and hydrophobic acid fractions in secondary effluent compete for the adsorption sites of the packed soil and lead to a declined ERY removal. Moreover, aerobic biodegradation was the predominant role for ERY removal, contributing more than 60% reduction of ERY when recharged with synthetic secondary effluent. Destruction of 14-member macrocyclic lactone ring and breakdown of two cyclic sugars (l-cladinose and d-desosamine) were main removal pathways for ERY degradation, and produced six new intermediates.     

Clean Development Mechanism Potential and Challenges in Sub-Saharan Africa

Sub-Saharan Africa lags far behind other regions in terms of the implementation of Clean Development Mechanism (CDM) projects due to several reasons. One of the reasons is a general perception that, since the region contributes very little to global GHG emissions, it also offers few opportunities to reduce these emissions. Using a bottom-up approach, this study investigates the technical potential of reducing GHG emissions from the energy sector in Sub-Saharan Africa through the CDM. The study finds that sub-Saharan Africa could develop 3,227 CDM projects, including 361 programs of activities, which could reduce approximately 9.8 billion tons of GHG emissions during the CDM project cycles. The study also estimates that the realization of this CDM potential could significantly enhance sustainable development in the region as it would attract more than US200 billion in investment and could generate US200 billion in investment and could generate US98 billion of CDM revenue at a CER price of US$10/tCO2. Another notable finding of the study is that the realization of this CDM potential could supply clean electricity by doubling the current capacity and thereby providing access of electricity to millions of people in the region. However, realization of this CDM potential is severely constrained by a number of financial, technical, regulatory and institutional barriers.     

Environmental cross-compliance mitigates nitrogen and phosphorus pollution from Swiss agriculture

In 1993 the Swiss agricultural policy was revised with – amongst other goals – the objective of improving the environmental performance of agriculture. A voluntary agri-environmental scheme to promote integrated production (IP) was introduced. In 1999 the IP standards were integrated in cross compliance requirements and termed Proof of Ecological Performance (PEP). We evaluated the effectiveness of this policy in terms of reducing diffuse nitrogen (N) and phosphorus (P) pollution of ground and surface water. We combined monitoring schemes covering the reference period from before the introduction of IP/PEP (1990–1992) with the evaluation of cause/effect relationships in selected case-study areas. The evaluation showed an overall reduction of diffuse N and P pollution from agriculture even though some goals were not reached. Nitrate leaching declined, but only a 3–4 mg L⁻¹ reduction was observed rather than the intended decrease of 5 mg L⁻¹. The P pollution of surface waters from agriculture decreased by only 10–30% instead of 50%. The intended reduction of the nitrogen surplus of Swiss agriculture by 33% was not attained, but the P surplus of Swiss agriculture was more than halved. IP/PEP practices that improved N and P management included reduced N and P fertiliser inputs and pig and poultry feedstuffs with reduced N and P contents, both of which are a consequence of the requirement of equilibrated farm nutrient balances, as well as increased use of cover cropping and of conservation tillage systems.     

Biofidelity Corridors for Sternum Kinematics in Low-Speed Side Impacts

Objective: Field data show that side impact car crashes have become responsible for a greater proportion of the fatal crashes compared to frontal crashes, which suggests that the protection gained in frontal impact has not been matched in side impact. One of the reasons is the lack of understanding of the torso injury mechanisms in side impact. In particular, the deformation of the rib cage and how it affects the mechanical loading of the individual ribs have yet to be established. Therefore, the objective of this study was to characterize the ribcage deformation in side impacts by describing the kinematics of the sternum relative to the spine.

Methods: The 3D kinematics of the 1st and of the 5th or 6th thoracic vertebrae and of the sternum were obtained for three Post Mortem Human Subjects (PMHS) impacted laterally by a rigid wall traveling at 15 km/h. The experimental data were processed to express the kinematics of the sternum relative to the spine throughout the impact event. Methods were developed to interpolate the kinematics of the vertebrae for which experimental data were not available.

Results: The kinematics of the sternocostal junction for ribs 1 to 6 as well as the orientation of the sternum were expressed in the vertebra coordinate systems defined for each upper thoracic vertebra (T1 to T6). Corridors were designed for the motion of the sternum relative to each vertebra. In the experiments, the sternum moved upward for all rib levels (1 to 6), and away from the spine with an amplitude that increased with the decreasing rib level (from rib 1 to rib 6). None of the differences observed in the kinematics could be correlated to the occurrence of rib fractures.

Conclusions: This study provides both qualitative and quantitative information for the ribcage skeletal kinematics in side impact. This data set provides the information required to better evaluate computational models of the thorax for side impact simulations. The corridors developed in this study provide new biofidelity targets for the impact response of the ribcage. This study contributes to augmenting the state of knowledge of the human chest deformation in side impact to better characterize the rib fracture mechanisms.     

The toxicity of cadmium-copper mixtures on daphnids and microalgae analyzed using the Biotic Ligand Model

For the prediction of metal mixture ecotoxicity, the BLM approach is promising since it evaluates the amount of metals accumulated on the biotic ligand on the basis of water chemistry, i.e., species (major cations) competing with metals, and related toxicity. Based on previous work by Farley et al. (2015) (MMME research project), this study aimed at modeling toxicity of Cd:Cu mixtures (0:1 - 1:1 - 1:0 - 1:2 - 1:3 - 2:1 - 3:1 - 4:1 - 5:1 - 6:1) to the crustacean Daphnia magna(48-h immobilization tests) and the microalga Pseudokirchneriella subcapitata (72-h growth inhibition tests). The 2012 version of the USGS model was chosen, assuming additivity of effects and accumulation of metals on a single site. The assumption that EDTA could contribute to toxicity through metals complexing was also tested, and potential effects due to reduction of ions Ca²⁺ absorption by metals were considered. Modeling started with parameter values of Farley et al. (2015) and some of these parameters were adjusted to fit modeled data on observed data. The results show that toxicity can be correctly predicted for the microalgae and that the hypothesis of additivity is verified. For daphnids, the prediction was roughly correct, but taking into account CuEDTA led to more realistic parameter values close to that reported by Farley et al. (2015). However, It seems that, for daphnids responses, metals interact either antagonistically or synergistically depending on the Cu:Cd ratio. Furthermore, synergy could not be explained by additional effects linked to a reduction of Ca absorption since this reduction, mainly due to Cd, increased inversely to synergy. Finally, the USGS model applied to our data was able to predict Cu:Cd mixture toxicity to microalgae and daphnids, giving rise to estimated EC50s roughly reflecting EC50s calculated from observed toxicity.

     

PBAT-based Microfiltration Membranes Using Porogen Saturated Solutions: Architecture,Morphology, and Environmental Profile

Journal of Polymers and the Environment - There is a scientific consensus that the use of membranes for water filtration presents itself as a promising research area for removing a wide range of...     

Fish community diversity in a coastal zone at southeastern Gulf of California,Mexico

Although the southeast region of the Gulf of California has a high fish diversity, due to the high biological productivity, the coastal area of Nayarit has few studies in this regard. The main objective of this work is to describe the variability of the structure of the ichthyofauna in the coastal zone of Nayarit during an annual cycle. Biological samples were collected at 10 stations during February, May, July, and December 2014. The temperature, depth, salinity, and organic material and carbonates in sediments were also recorded. The analysis of diversity includes three facets: ecological, taxonomic, and functional. A total of 82 species belonging to 56 genera, 31 families, 11 orders, and two classes were identified. The most abundant species included Selene peruviana, Stellifer wintersteenorum, Cathorops sp., and Larimus argenteus. Of the total of identified species, 62% were considered as rare according to their abundance and frequency. Although the environmental variables analyzed were variable, all diversity indices did not reveal an evident spatio-seasonal pattern. Likewise, most values of average taxonomic distinctness presented the expected values. However, some values showed a low taxonomic diversity. The indices of functional diversity showed a stable functional richness and redundancy in the attributes of the species.