Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting

Gaseous emission (N₂O, CH₄ and NH₃) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of CO₂ and 0.8% to 7.5% of TOC emitted as CH₄. Most of the nitrogen was lost in the form of NH₃, which account for 9.6% to 32.4% of initial nitrogen. N₂O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could affect the NH₃ (p = 0.0189), CH₄ (p = 0.0113) and N₂O (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH₄ emission but increase the NH₃ and N₂O losses. C/N ratio could affect the NH₃ (p = 0.0442) and CH₄ (p = 0.0246) emissions significantly, but not the N₂O. Lower C/N ratio caused higher NH₃ and CH₄ emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.     

Accumulation of potentially toxic elements by plants of North Caucasian Alyssum species and their molecular phylogenetic analysis

Environmental Geochemistry and Health - Accumulations of potentially toxic metals were investigated in soils and five North Caucasian Alyssum species from metalliferous areas and non-metalliferous...     

Seasonal evolution of beach waste and litter during the bathing season on the Catalan coast

Beach waste and litter composition and evolution on popular urban (located in the main nucleus of the municipality) and urbanized (located in residential areas outside the main nucleus) beaches of the Costa Brava (Catalan coast) were assessed during the bathing season. Waste and litter production (amount and composition) were affected by urbanization and varied during the summer. Urban beaches had higher densities of waste deposition and lower percentages of organic, domestic and other miscellaneous waste than urbanized beaches. Litter characteristics were also influenced by type of beach, and varied during the season as a consequence of beach use and cleaning practices, but not environmental factors. Urbanized beaches obtained higher scores for aesthetic quality of sand than urban beaches, and small-sized litter tended to accumulate during the season in the beach of Lloret Centre. The most important problems are management of recyclable materials, litter left by users on the sand, and separation of sand from litter. In addition, current efficiency of mechanical cleaning is low, especially in the withdrawal of cigarette butts. These analyses highlight problems that should be addressed in future management of area beaches.     

Stage-based approach to the management of fetal growth restriction

Fetal growth restriction (FGR) is among the obstetrical entities with the greatest variation in clinical practice. The first clinically relevant step in the management of FGR is the distinction of ‘true’ FGR, associated with signs of abnormal feto-placental function and poorer perinatal outcome, from small for gestational age fetuses, which do not present abnormal Doppler and have near normal perinatal outcome. Such distinction should not be only relied on umbilical artery Doppler, as this parameter identifies only severe, early-onset, forms of placental insufficiency. Instead, FGR should be diagnosed in the presence of any of the factors associated with a poorer perinatal outcome, including Doppler cerebroplacental ratio and uterine artery Doppler, a growth centile below the third centile. Upon diagnosis, differentiating into early-onset and late-onset FGR is useful to distinguish two clear phenotypes, with differences in severity, association with preeclampsia, and sequence of fetal deterioration. Finally, management of FGR aims at an optimal balance between minimizing fetal injury or death versus the risks of iatrogenic preterm delivery. We propose a protocol that integrates current evidence to classify stages of fetal deterioration, and establishes follow-up intervals and optimal delivery timings, which may facilitate decision-making and minimize variability in the clinical management. © 2014 John Wiley & Sons, Ltd.