The effects of burial by sand on survival and growth of Pitcher’s thistle (Cirsium pitcheri) along lake huron

Greenhouse experiments were conducted to determine the effects of sand burial on survival and growth of seedlings ofCirsium pitcheri. In 1992–1993, seedlings were buried to depths of 0, 25, 50, 75, and 100% of their height while in 1993–1994, the seedlings were buried to depths of 0, 4 cm (single burial), 4 cm (repeated burial of 1 cm every 8 days), 8 cm (single burial) and 8 cm (repeated burial of 2 cm every 8 days). Several physiological traits, net photosynthetic rate, chlorophyll a∶b ratio, leaf area, number and length of leaves, number of internodes, amount of tillering, and biomass, were measured. The results showed that all seedlings died in the complete (100%) burial, 20% died in the 75% burial and none died in the 0, 25 and 50% burial treatments. Burial of seedlings to a depth of 25% stimulated their growth but 75% burial significantly decreased the total dry weight. Repeated burial treatments exhibited significantly greater stimulation of growth than single burial. Surviving seedlings grew through the sand deposit by elongating the stem and leaf petioles, increasing the number of nodes and the length of internodes. This elongation occurred at the expense of development of the root system indicating that available energy was re-allocated to above-ground parts.     

Insight into fluorescence properties of 14 selected toxic single-ring aromatic compounds in water: Experimental and DFT study

• The fluorescence peak location of 14 compounds interpreted at protein-like region. • The p-electron system inside aromatic ring contributes to the fluorophore region. • Functional group variation effects the emission spectra. • Decrease in quantum yield and increase in DE is due to atomic weight F>Cl>Br>I. • Theoretically results are in line with experimental ones. Various single-ring aromatic compounds in water sources are of great concern due to its hazardous impact on the environment and human health. The fluorescence excitation-emission matrix (EEMs) spectrophotometry is a useful method to identify organic pollutants in water. This study provides a detailed insight into the fluorescence properties of the 14 selected toxic single-ring aromatic compounds by experimental and theoretical analysis. The theoretical analysis were done with Time-Dependent Density Functional Theory (TD-DFT) and B3LYP/6-31G (d,p) basis set, whereas, Polarizable Continuum Model (PCM) was used to consider water as solvent. The selected compounds displayed their own specific excitation-emission (Ex/Em) wavelengths region, at Ex<280 nm and Em<340 nm, respectively. Whereas the theoretical Ex/Em was observed as, Ex at 240 nm–260 nm and Em at 255 nm–300 nm. Aniline as a strong aromatic base has longer Em (340 nm) than alkyl, carbonyl, and halogens substituted benzenes. The lone pair of electrons at amide substituent serves as a p-electron contributor into the aromatic ring, hence increasing the stability and transition energy, which results in longer emission and low quantum yield for the aniline. The fluorescence of halogenated benzenes illustrates an increase in the HOMO-LUMO energy gap and a decrease in quantum yield associated with atomic size (F>Cl>Br>I). In this study the theoretical results are in line with experimental ones. The understanding of fluorescence and photophysical properties are of great importance in the identification of these compounds in the water.     

Chemical fractionation and risk assessment of trace elements in sewage sludge generated from various states of Pakistan

Environmental Science and Pollution Research - In the developing world, rapid urbanization and industrialization produces an enormous volume of wastes daily. This study was aimed to explore the...     

Industrialization,Freight Transport and Environmental Quality: Evidence from Belt and Road Initiative Economies

Environmental Science and Pollution Research - Belt and Road initiative has been proposed by China to initiate the cooperation among relevant countries in sector of energy and Trade. The...     

Attribute-based analysis of hunters’ lease preferences

Understanding of hunter preferences for hunting lease attributes is important to landowners because such knowledge provides key information for managing and marketing fee-hunting in order to maximize revenues. Premised on this insight, we used attribute based modeling to investigate how hunter preferences for potential leases were influenced by lease and hunter-specific attributes. A mail survey of Mississippi licensed hunters provided the necessary data. Estimation results based on McFadden conditional logit regression suggested that lease attributes including game diversity, lease location relative to hunter residence, lease size, lease duration and lease rate influenced willingness to pay for additional units of lease attributes. Depending on the specific levels of these attributes, WTP could vary as much as $5.70 per acre. Of the hunter-specific attributes, age and income significantly influenced hunter decision to buy a lease or opt for status quo. Results of this study should assist landowners in increasing financial returns from fee-hunting endeavors through appropriate changes to their hunting access policies and wildlife management activities in response to hunter preferences regarding lease attributes.     

The role of infrastructure,socio-economic development,and food security to mitigate the loss of natural disasters

Environmental Science and Pollution Research - This study shows the impact of risk (hazard, exposure, and vulnerability) and resilience (infrastructure, information and communication technology,...     

The influence of FDI on GHG emissions in BRI countries using spatial econometric analysis strategy: the significance of biomass energy consumption

Environmental Science and Pollution Research - Indeed, the Belt and Road Initiative (BRI) plays an increasingly important role in global economic and climate change mitigation. However, scientists...     

Occurrence, finger printing and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the Chenab River, Pakistan

Seventeen polycyclic aromatic hydrocarbons (PAHs) were studied in surface waters (including particulate phase) from the Chenab River, Pakistan and ranged from 289-994 and 437-1290 ng l(-1) in summer and winter (2007-09), respectively. Concentrations for different ring-number PAHs followed the trend: 3-rings > 2-rings > 4-rings > 5-rings > 6-rings. The possible sources of PAHs are identified by calculating the indicative ratios; appropriating petrogenic sources of PAHs in urban and sub-urban regions with pyrogenic sources in agricultural region. Factor analysis based on principal component analysis identified the origins of PAHs from industrial activities, coal and trash burning in agricultural areas and municipal waste disposal from surrounding urban and sub-urban areas via open drains into the riverine ecosystem. Water quality guidelines and toxic equivalent factors highlighted the potential risk of low molecular weight PAHs to the aquatic life of the Chenab River. The flux estimated for PAHs contaminants from the Chenab River to the Indus River was >50 tons/year.