Hydrocarbons in particulate samples from wildfire events in central Portugal in summer 2010

In summer 2010, twenty eight(14 PM_(2.5)samples plus 14 samples PM_(2.5–10)) smoke samples were collected during wildfires that occurred in central Portugal. A portable high-volume sampler was used to perform the sampling, on quartz fibre filters of coarse(PM_(2.5–10)) and fine(PM_(2.5)) smoke samples. The carbonaceous content(elemental and organic carbon) of particulate matter was analysed by a thermal–optical technique. Subsequently, the particulate samples were solvent extracted and fractionated by vacuum flash chromatography into three different classes of organic compounds(aliphatics, polycyclic aromatic hydrocarbons(PAHs) and carbonyl compounds). The organic speciation was performed by gas chromatography–mass spectrometry(GC–MS). Emissions were dominated by the fine particles, which represented around 92% of the PM_(10). A clear predominance of carbonaceous constituents was observed, with organic to elemental carbon(OC/EC)ratios ranging between 1.69 and 245 in both size fractions. The isoprenoid ketone6,10,14-trimethyl-2-pentadecanone, a tracer for secondary organic aerosol formation, was one of the dominant constituents in both fine and coarse particles. Retene was the most abundant compound in all samples. Good correlations were obtained between OC and both aliphatic and PAH compounds. Pyrogenic processes, thermal release of biogenic compounds and secondary processing accounted for 97% of the apportioned PM_(2.5)levels.     

Defining Nutrient and Biochemical Oxygen Demand Baselines for Tropical Rivers and Streams in São Paulo State (Brazil): A Comparison Between Reference and Impacted Sites

Determining reference concentrations in rivers and streams is an important tool for environmental management. Reference conditions for eutrophication-related water variables are unavailable for Brazilian freshwaters. We aimed to establish reference baselines for São Paulo State tropical rivers and streams for total phosphorus (TP) and nitrogen (TN), nitrogen-ammonia (NH₄ ⁺) and Biochemical Oxygen Demand (BOD) through the best professional judgment and the trisection methods. Data from 319 sites monitored by the São Paulo State Environmental Company (2005 to 2009) and from the 22 Water Resources Management Units in São Paulo State were assessed (N = 27,131). We verified that data from different management units dominated by similar land cover could be analyzed together (Analysis of Variance, P = 0.504). Cumulative frequency diagrams showed that industrialized management units were characterized by the worst water quality (e.g. average TP of 0.51 mg/L), followed by agricultural watersheds. TN and NH₄ ⁺ were associated with urban percentages and population density (Spearman Rank Correlation Test, P < 0.05). Best professional judgment and trisection (median of lower third of all sites) methods for determining reference concentrations showed agreement: 0.03 &; 0.04 mg/L (TP), 0.31 &; 0.34 mg/L (TN), 0.06 &; 0.10 mg-N/L (NH₄ ⁺) and 2 &; 2 mg/L (BOD), respectively. Our reference concentrations were similar to TP and TN reference values proposed for temperate water bodies. These baselines can help with water management in São Paulo State, as well as providing some of the first such information for tropical ecosystems.     

A systematic investigation of carbamate stability constants by 1H NMR

A systematic, experimental investigation into carbamate stability constants using ¹H NMR spectroscopy reveals that both steric hindrance and the acid dissociation constant of the parent amine have a significant effect on the stability of the resulting carbamates. Increasing steric hindrance was found to decrease carbamate stability, while increasing pK of the parent amine was found to increase carbamate stability. The carbamate stability constants of monoethanolamine, propylamine, isobutylamine, 2-amino-1-propanol, aminomethylpropanol and methyldiethanolamine were determined as were the carbamate protonation constants of the first four of these amines.     

Model parameterization for aerobic decomposition of plant resources drowned during man-made lakes formation

The formation of man-made reservoirs generates several impacts on water quality. In order to minimize some of these impacts mathematical models are currently used. This paper aims to discuss the issue associated with the degradation of plant resources (leaves, branches, barks and litter) that remain within the watershed of the new man-made lakes and parameterize a kinetic model related to decay of plant detritus. In these environments, the short-term variation of limnological parameters is mainly connected with biomass decay drowned during the filling operation. The kinetics of the degradation processes in reservoirs are discussed on the basis of information with related to detritus sources and the chemical properties of different types of compounds (i.e. labile and refractory fractions). Overall, the parameterization of the (first order) kinetic model showed that refractory fractions (ca. 86%) are predominant and the mineralization is a slow process, constituting the main route for decomposition and being affected by changes of environmental variables. The mineralization of labile and hydrosoluble compounds (ca. 14%) is responsible for the short-term water quality variation owing to decomposition; basically, the intensities of these changes depend on the labile/soluble compounds content of detritus and its chemical composition.     

Nitrate levels modulate denitrification activity in tropical mangrove sediments (Goa, India)

A study to examine the short-term effect of nitrate and organic carbon addition on denitrification activity was carried out on sediments from a mangrove ecosystem prone to anthropogenic activities (Divar, Goa, India). Laboratory microcosms were prepared using sediment sectioned at every 2-cm-depth interval from the surface to 10 cm. The incubations were subjected to varying nitrate amendments at concentrations ranging from 0, 5, 10, 20, 40 to 60 ??mol l^???1 (up to three times more than measured in field). Nitrous oxide production rates increased significantly (n?=?15; p?<?0.001) on addition of the nutrient at all depths investigated indicating that denitrification in mangrove sediments was NO $_{3}^{-}$ limited. Incubations amended with organic carbon were prepared using glucose as a substrate with concentrations ranging from 0%, 0.1%, 0.3%, 0.5%, 0.75% to 1%. No significant increase in N₂O production was observed on organic C addition. When both the substrates were in excess (1 mmol KNO₃ + 1 mmol glucose), potential denitrification rates decreased with depth and were up to 38 times higher than the in situ denitrification activity varying from 81.26 to 304.09 ??mol N₂O-N m^???2 h^???1. These results reveal that mangrove sediments could act as a sink for nitrate and microbially mediated denitrification could effectively reduce N load controlling any adverse environmental impact in the adjoining estuarine system.     

Adsorptive and photocatalytic activity of Fe3O4-functionalized multilayer graphene oxide in the treatment of industrial textile wastewater

Environmental Science and Pollution Research - Multilayer graphene oxide (mGO) was synthesized and functionalized via co-precipitation method to produce magnetic Fe3O4-functionalized multilayer...     

Four challenges when conducting bibliometric reviews and how to deal with them

Environmental Science and Pollution Research - The evidence base in environmental sciences is increasing steadily. Environmental researchers have been challenged to handle massive volumes of data...     

Fishers’ knowledge detects ecological decay in the Mediterranean Sea

The Northern Adriatic Sea (NAS) is one of the most overexploited marine ecosystems in Europe. Given the gaps in scientific knowledge regarding the NAS, this study sought Fishers’ Ecological Knowledge (FEK) to determine NAS’ historical baselines for conservation. By interviewing 53 fishers in three ports of northern Italy, estimates of the catch rates of four commercial demersal species were generated over a 60-year period, and perceptions of target and non-target species’ diversity and benthic diversity were analysed in three groups of fishers (i.e. novices, experienced and veterans). Results showed a significant decline in perceived abundance of sole (Solea solea), common cuttlefish (Sepia officinalis) and mantis shrimp (Squilla mantis), and evidence was found of a Shifting Baseline Syndrome (SBS) among novices. Given FEK’s ability to complement scientific knowledge, fishers’ participation in marine management policies and intergenerational communication should be enhanced, to improve the status of marine ecosystems and hinder SBS.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01452-3) contains supplementary material, which is available to authorized users.