Lignin and its effects on litter decomposition in forest ecosystems

Lignin is a major component of plant litter. In this review, we found lignin comprises a complex class of organic compounds whose concentration differs greatly both between and within plant species. There are many analytical methods for detecting the composition and structure of lignins. As lignins are enormously complex compounds, chemical assay is difficult and different methods vary with the results. Lignin plays a significant role in the carbon cycle, sequestering atmospheric carbon into the living tissues of woody perennial vegetation. It has also great effects on nitrogen dynamics of forest ecosystems as well as other ecological processes. Lignin is one of the most slowly decomposing components of dead vegetation, contributing a major fraction of the material that becomes humus as it decomposes. Lignin is highly correlated with decomposition of litter. Thus, there is evidence that the lignin concentration is a more influential factor than the other chemical concentrations, in determining the rate of leaf litter decomposition of different forest ecosystems. Although a great number of researchers have addressed lignin's role in litter decomposition, still there are many aspects of lignin biogeochemistry that are not known. This lack of information hinders complete amalgam of lignin effects on litter decomposition processes and dynamics of nutrient cycling.     

Environmental change and vulnerability in the Usangu plain,southwestern Tanzania: Implications for sustainable development

Natural resources are important assets for sustainability of rural livelihoods and economic development. The objectives of the study were to assess linkage of environmental change to emerging water scarcity, livelihoods insecurity and decline in wildlife biodiversity and hydropower generation in the Great Ruaha ecosystem, and to discuss policy lessons for sustainable development. Literature survey, participatory assessments, collection of records from stakeholders, participatory observations and a questionnaire survey were used. Participatory assessment found that increasing water scarcity is associated with degradation of land, vegetation cover and change in rainfall intensity and duration. Rainfall change is supported by 83% of respondents and rainfall trends analysis. About 42% of variation in cereal production is described by the rainfall amount variability. Analysis of trends for per capita cereals production from district records showed a significant (p < 0.05) decline over the years. Changes in water flows in the Great Ruaha River have been evident since 1993, and have affected wildlife diversity in the Ruaha National Park and power generation from the Kidatu hydroelectric plant downstream. Human livelihood activities, exclusiveness, weak coordination and collaboration between sectors and institutions in policy formulation and implementation have played a role. The pro-poor policy formulation through integrated planning, strong coordination and collaboration is recommended for sustainable development.     

Toxic impact of nanomaterials on microbes,plants and animals

Nanotechnology has many potential applications in medical, agriculture, electronic and sports industries. Nonetheless, there is actually little knowledge on toxic effects of nanomaterial. Here we review nanotoxicity, action mechanisms and fate of nanomaterials. We discuss the impact of nanotoxicity on microbes, plant, animal and human health, and factors like size, shape, surface charge, composition, ionic concentration and physiological. We explain the detection of nanotoxicity at cell and genome levels. Toxicities of commercial nanomaterials, risk management, rules and regulations regarding marketed nanoproducts are also summarized.     

Modeling of road traffic noise and estimated human exposure in Fulton County, Georgia, USA

Environmental noise is a major source of public complaints. Noise in the community causes physical and socio-economic effects and has been shown to be related to adverse health impacts. Noise, however, has not been actively researched in the United States compared with the European Union countries in recent years. In this research, we aimed at modeling road traffic noise and analyzing human exposure in Fulton County, Georgia, United States. We modeled road traffic noise levels using the United States Department of Transportation Federal Highway Administration Traffic Noise Model implemented in SoundPLAN?. After analyzing noise levels with raster, vector and fa?ade maps, we estimated human exposure to high noise levels. Accurate digital elevation models and building heights were derived from Light Detection And Ranging survey datasets and building footprint boundaries. Traffic datasets were collected from the Georgia Department of Transportation and the Atlanta Regional Commission. Noise level simulation was performed with 62 computers in a distributed computing environment. Finally, the noise-exposed population was calculated using geographic information system techniques. Results show that 48% of the total county population [N=870,166 residents] is potentially exposed to 55 dB(A) or higher noise levels during daytime. About 9% of the population is potentially exposed to 67 dB(A) or higher noises. At nighttime, 32% of the population is expected to be exposed to noise levels higher than 50 dB(A). This research shows that large-scale traffic noise estimation is possible with the help of various organizations. We believe that this research is a significant stepping stone for analyzing community health associated with noise exposures in the United States.     

Eco-material selection using fuzzy TOPSIS method

In the classical multiple attribute decision-making or MADM methods, the ratings and the weights of the criteria are known precisely. However, in eco-material selection exercises, the available data are typically inadequate because of the selection dual quantitative and qualitative natures. Some of the qualitative selection criteria can be rated in several classes rather being expressed by exact numerical values; hence the application of fuzzy concepts in decision-making seems attractive to deal with such kind of ratings. Thusly, the presented study attempts to propose an eco-material selection approach specific to the automobile body panels using a fuzzy technique for order preference by similarity to ideal solution (TOPSIS), to incorporate both numerical and rating-based criteria into one holistic sustainability model. TOPSIS and fuzzy logic can aid the material selection process in translating the design goals and parameters into usable numbers that in turn can be used to rank candidate materials in their closeness to the ideal solution. An additional uniqueness of this study stems from using the fuzzy-TOPSIS as a scoring tool without any assigned weights for the different selection attributes, in order to avoid the bias that is typically associated with other classical MADM, such as quality function deployment, analytical hierarchy process and digital logic.     

Polycyclic aromatic hydrocarbons in crude oil-contaminated soil: A two-step method for the isolation and characterization of PAHs

A two-step analytical method is developed for the isolation and characterization of polycyclic aromatic hydrocarbons (PAHs) in crude oil contaminated soil. In the first step, those crude oil components were isolated which are easily mobilized with water from the contaminated soil (determination of groundwater pollution potential). In the second step, the fraction containing the remaining crude oil compounds was extracted using toluene. After the cleanup of the fractions, both fractions were analyzed using high-performance liquid chromatography (HPLC). The HPLC of the toluene extracted fraction shows that along with the sixteen priority pollutants from the US-EPA list, many other polycyclic aromatic hydrocarbons (PAHs) are present as well. It is evident from the chromatograms that a significant amount of PAHs are present as is also the case in the fractions eluted by water. The described method allows the determination of total organic pollutants from crude oil, some of them being potential groundwater contaminants. The major part of the total pollutants could not be mobilized by water and therefore remains in the soil, which was extracted in the second step.     

Seasonal variations in cholinesterase activity, nerve conduction velocity and lung function among sprayers exposed to mixture of pesticides

Pesticide spraying operation is associated with the increased risk of adverse health effects among sprayers who do not follow safe farm work practices. A study was conducted among pesticide sprayers in North India to evaluate the clinical and subclinical variations in their vital health parameters before and after the pesticide spraying season. Blood cholinesterase levels, pulmonary function test, nerve conduction velocity and self-reported symptoms were studied among 18 eligible and consenting male sprayers. Mean acetylcholinesterase activity was reduced by 55 % in the post-exposure assessment (P?<?0.001) as compared to pre-exposure levels. Mean forced expiratory volume in 1 s was 20 % lower in the post-exposure assessment as compared to the pre-exposure level (P?<?0.05). No significant change was observed in the motor and sensory nerve conduction velocity in the median nerve of sprayers before and after the spraying activity. Also, no significant variation was observed with respect to self-reported symptoms except weakness in arms and legs (P?<?0.05). The significant decline in lung function and acetylcholinesterase level after pesticide exposure reflects the strongly negative effect of exposure to pesticides during spraying activity. More longitudinal studies among pesticide sprayers must be undertaken to further substantiate the cause–effect relationship between pesticide exposure and its subclinical effects. There is a strong necessity to minimise the exposure through the use of personal protective equipment in pesticide sprayers.     

Sleepy driving and risk of obstructive sleep apnea among truck drivers in Saudi Arabia

Objective: Truck drivers represent a group at a particularly higher risk of motor vehicle accidents (MVAs). Sleepy driving and obstructive sleep apnea (OSA) among truck drivers are major risk factors for MVAs. No study has assessed the prevalence of sleepy driving and risk of OSA among truck drivers in Saudi Arabia. Therefore, this study aimed to assess sleepy driving and risk of OSA among these truck drivers.

Methods: This study included 338 male truck drivers working in Saudi Arabia. A validated questionnaire regarding sleepy driving and OSA was used. The questionnaire included sociodemographic assessment, the Epworth Sleepiness Scale (ESS), the Berlin Questionnaire (BQ), and driving-related items.

Results: The drivers had a mean age of 42.9?±?9.7 years. The majority (94.7%) drove more than 5?h a day. A history of MVAs during the last 6 months was reported by 6.5%. Approximately 95% of the participants reported that they had accidentally fallen asleep at least once while driving over the past 6 months, and 49.7% stated that this had happened more than 5 times during the last 6 months. Based on the BQ score, a high risk of OSA was detected in 29% of the drivers. “Not getting good-quality sleep” (odds ratio [OR]?=?2.89; 95% confidence interval [CI], 1.08–7.75; P = .014) and driving experience from 6 to 10 years (OR = 3.37; 95% CI, 1.28–8.91; P = .034) were the only independent predictors of MVAs in the past 6 months.

Conclusions: Sleepy driving and a high risk of OSA was prevalent among the study population of male truck drivers in Saudi Arabia. Not getting good-quality sleep and driving experience from 6 to 10 years contributes to the accident risk among these truck drivers.     

Identification of rainfall homogenous regions in Saudi Arabia for experimenting and improving trend detection techniques

Environmental Science and Pollution Research - In Saudi Arabia, identifying homogenous zones based on rainfall patterns is critical for ensuring a predictable and stable water resource and...     

Pharmacological and ameliorative effects of Withania somnifera against cadmium chloride–induced oxidative stress and immune suppression in Nile tilapia,Oreochromis niloticus

This study was carried out to evaluate the effects of dietary supplementation of aqueous extract of Withania somnifera (W. somnifera) against cadmium chloride–induced toxicity in the Nile tilapia, Oreochromis niloticus. Five experimental groups were designed: group (I) was free from cadmium chloride and W. somnifera and served as a control, group (II) was exposed to 1.775 mg L^?1 of cadmium chloride only (which is equivalent to 1/4 96-h LC50), while groups (III), (IV), and (V) were exposed to 1.775 mg cadmium chloride L^?1 with co-supplementation of dietary W. somnifera in doses of 1.0, 2.0, and 3.0 mL kg^?1 body weight (bwt), respectively. The experiment lasted for 4 weeks. In the second and fourth weeks of the experiment, the following indicators were evaluated: hematological (hemogram and blood protein profile), biochemical (activities of serum liver enzymes, namely alanine transaminase (ALT) and aspartate transaminase (AST)), immunological (immunoglobulin M (IgM), serum lysozyme), and tissue antioxidant changes (malondialdehyde (MDA) levels and activities of catalase (CAT) and superoxide dismutase (SOD)). Additionally, gene expressions of glutathione-S-transferase (GST) in the liver were assessed. At the end of the experiment, all fish in all groups were experimentally challenged with Aeromonas hydrophila and the relative protection survival (RPS) was demonstrated. The results revealed that groups exposed to cadmium chloride toxicity and co-supplemented with dietary aqueous extract of W. somnifera at high doses showed significant ameliorative effects in hemogram parameters, total protein, globulin, IgM, and lysozyme against cadmium chloride–induced toxicity compared to the control group and the group exposed to a sublethal dose of cadmium chloride without co-suplemntation of W. somnifera. The results showed also that groups supplemented orally with W. somnifera at high doses have higher antioxidant activities of CAT and SOD and reduction of MDA formation. Levels of gene expressions of GST in the liver were higher in W. somnifera extract-supplemented groups more than those in the group exposed to cadmium chloride–induced toxicity without W. somnifera supplementation. In addition, the results revealed improved RPS with the dietary supply of W. somnifera extract in high doses. In conclusion, this study showed that the dietary supplementation of W. somnifera extract to diets of O. niloticus could be suggested as an effective way to overcome cadmium chloride–induced toxicity because it improves blood parameters and antioxidants, and it can be used as an immunostimulant against the invading bacterial pathogens.