Search results for "POLLUTANTs"

Allelopathic effects of microcystin-LR on the germination, growth and metabolism of five charophyte species and a submerged angiosperm

2013

Abstract Microcystins (MCs) are produced by cyanobacteria in aquatic environments and adversely affect macrophytes at very high concentrations. However, the effects of MC on macrophytes at concentrations of environmental relevance are largely unknown. The main objective of this study was to analyze the allelopathic effects of MC-LR at natural concentrations (1, 8 and 16 μgMC-LR/L) on five charophyte species ( Chara aspera , C. baltica , C. hispida , C. vulgaris and Nitella hyalina ) and the angiosperm Myriophyllum spicatum . Macrophyte specimens were obtained from a restored area located in Albufera de Valencia Natural Park, a protected coastal Mediterranean wetland. Two different experimen…

Special issue “chemical speciation of organic and inorganic components of environmental and biological interest in natural fluids: Behaviour, interac…

2020

Several different definitions were in the past proposed to describe the term chemical speciation, and some of them were accepted from the scientific community [...]

Theoretical Investigations of the Wet Deposition of Atmospheric Pollutants

2007

Use of semipermeable membrane devices for assessment of air quality in Tangier (Morocco)

2009

Semipermeable membrane devices (SPMDs) have been used for the evaluation of the contamination of air in both the urban and the industrial area in Tangier (Morocco). Benzene, toluene, ethylbenzene a...

Molecular Characterization and Source Identification of Atmospheric Particulate Organosulfates Using Ultrahigh Resolution Mass Spectrometry.

2019

Organosulfates (OSs) have been observed as substantial constituents of atmospheric organic aerosol (OA) in a wide range of environments; however, the chemical composition, sources, and formation mechanism of OSs are still not well understood. In this study, we first created an "OS precursor map" based on the elemental composition of previous OS chamber experiments. Then, according to this "OS precursor map", we estimated the possible sources and molecular structures of OSs in atmospheric PM2.5 (particles with aerodynamic diameter ≤ 2.5 μm) samples, which were collected in urban areas of Beijing (China) and Mainz (Germany) and analyzed by ultrahigh-performance liquid chromatography (UHPLC) c…

Radical Formation by Fine Particulate Matter Associated with Highly Oxygenated Molecules

2019

Highly oxygenated molecules (HOMs) play an important role in the formation and evolution of secondary organic aerosols (SOA). However, the abundance of HOMs in different environments and their relation to the oxidative potential of fine particulate matter (PM) are largely unknown. Here, we investigated the relative HOM abundance and radical yield of laboratory-generated SOA and fine PM in ambient air ranging from remote forest areas to highly polluted megacities. By electron paramagnetic resonance and mass spectrometric investigations, we found that the relative abundance of HOMs, especially the dimeric and low-volatility types, in ambient fine PM was positively correlated with the formatio…

HCHs and DDTs in sediment-dwelling animals from the Yangtze Estuary, China

2005

HCHs and DDTs in sediment-dwelling animals including mollusks and crabs from the Yangtze Estuary were deter- mined by GC-ECD. Levels of t-HCH were in the range of 1.2-5.5 ng g � 1 and averaged 3.5 ng g � 1 in mollusks, while t-DDT concentrations ranged from 26.0 to 68.8 ng g � 1 , with a mean of 34.5 ng g � 1 . In crabs t-HCH concentrations var- ied from 2.0 to 25.7 ng g � 1 and averaged 13.8 ng g � 1 , whereas the concentrations of t-DDT were in the range of 1.5- 24.8 ng g � 1 with a mean value of 5.9 ng g � 1 . The HCHs and DDTs levels depend on geographical position and sources, showing the high levels at fresh water area in the estuary, such as XP, CM and LHK sites, and lower at brackis…

Tracing anthropogenic thallium in soil using stable isotope compositions.

2014

Thallium stable isotope data are used in this study, for the first time, to apportion Tl contamination in soils. In the late 1970s, a cement plant near Lengerich, Germany, emitted cement kiln dust (CKD) with high Tl contents, due to cocombustion of Tl-enriched pyrite roasting waste. Locally contaminated soil profiles were obtained down to 1 m depth and the samples are in accord with a binary mixing relationship in a diagram of Tl isotope compositions (expressed as e(205)Tl, the deviation of the (205)Tl/(203)Tl ratio of a sample from the NIST SRM 997 Tl isotope standard in parts per 10(4)) versus 1/[Tl]. The inferred mixing endmembers are the geogenic background, as defined by isotopically l…

Toxicity of fullerene (C60) to sediment-dwelling invertebrate Chironomus riparius larvae

2011

An environmentally realistic method to test fullerene (C(60) ) toxicity to the benthic organism Chironomus riparius was created by allowing suspended fullerenes to settle down, making a layer on top of the sediment. To test the hypothesis that higher food concentrations will reduce toxic responses, two food concentrations were tested (0.5 and 0.8% Urtica sp.) in sediment containing fullerene masses of 0.36 to 0.55 mg/cm(2) using a 10-d chronic test. In the 0.5% food level treatments, there were significant differences in all growth-related endpoints compared with controls. Fewer effects were observed for the higher food treatment. Fullerene agglomerates were observed by electron microscopy …

An in-tube SPME device for the selective determination of chlorophyll a in aquatic systems.

2010

We report a new device for the estimation of the content of chlorophyll a pigment in water samples as an indicator of water quality. The extraction of the pigment from water was also optimized. 10 mL of water was filtered through a nylon filter (45m pore size and 13 mm of diameter), after the chlorophylls were dissolved by immersing the filter in 1 mL of a low non-hazardous solvent as ethanol. An in-valve in-tube SPME device coupled to capillary liquid chromatography with diode array detection was designed. A capillary column of 70 cm in length (0.32 mm i.d. coated with 5% diphenyl–95% polydimethylsiloxane, 3m coating thickness) was used as the loop of the injection valve for preconcentrati…