Causes of salinity and plant manifestations to salt stress: a review

Salinity in agricultutal terms is the excess of salts above the level plant require. Most often it poses constrains in the growth hence productivity of the category of plants called glycophytes, wherein falls major crops, therefore is a serious concern. It is often recognized as excess of sodium ions (sodicity) that imparts life threatening consequences in plant due to mal-textured soil hindered porosity and aeration leads to physiological water deficit. Mingling with other edaphic/environmental factors viz. precipitation, temperature, flooding, soil profile, water table exaggerates the catastrophe synergistically. Improper irrigations system, leaching fraction added with land clearing and deforestation have been marked as the major cause. The present review underlines the different sources of salinity stress and their physiological manifestations, toxicity responses alongwith tolerance in plants and management strategies in affected landscapes.     

Understanding of groundwater salinity using statistical modeling in a small tropical island,East Malaysia

This paper presents an understanding of groundwater salinity by identification of effective factors using chemometric methods (cluster analysis and multiple linear regressions) in Manukan Island, Sabah. Local groundwater and environmental properties were used to explore the effective factors of groundwater salinity. Cluster analysis showed salinity and chloride illustrated the highest similarities. Electrical conductivity and total dissolved solids were also grouped in the same cluster. Seawater is the only chloride source in groundwater of Manukan Island demonstrated an indication of seawater mixing in freshwater. It is an effect of upward movement of the seawater by pumping activities. Precipitation and evapotranspiration (environmental condition) with hydraulic heads were clustered together to show that they also influence salinity concentration in groundwater. Multiple linear regressions showed descending order of the factors from chloride (the largest contribution) to evapotranspiration (the smallest contribution) and illustrated the contribution to groundwater salinity in Manukan Island. The integrated results using chemometric methods have provided a way to identify the effective factors on groundwater salinity. This similar approach and resulting equation can be applied in other small tropical islands with alike hydrogeological condition and limited information available for a better understanding of its groundwater salinity.     

The impact of urban growth on regional air quality surrounding the Langat River Basin, Malaysia

Studies of air quality were carried out in the towns of Kajang, Nilai and Banting in the Langat River Basin, southern region of Kuala Lumpur to determine the status and trend of air quality. The determination of air quality was based on several parameters such as suspended solids with diameters less than 10???m (PM₁₀) and gaseous pollutants of sulphur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), and carbon monoxide (CO). Primary concentration data of air pollutants were compiled through fieldwork studies and combined with secondary data obtained from the regular monitoring data as collected by Alam Sekitar Malaysia Sdn. Bhd. (ASMA) on behalf of Malaysian Department of Environment (DOE) at their stations in Kajang and Nilai. Results showed that the average concentrations of PM₁₀, SO₂, NO₂, O_3, and CO at all sampling stations were still below the permissible values recommended by the Malaysian DOE. The level of gaseous pollutants of NO₂, O_3, and CO was recorded at statistically higher levels (p?<?0.05) than values recorded at the control station at Pangsun Recreational Area. These pollutants were suspected to have originated mainly from exhaust systems of motor vehicles. Data for the years 1996 to 2006 as obtained from ASMA showed long-term air quality trends of increasing O₃ and NO₂ concentrations in Kajang whilst concentrations of PM₁₀ recorded at both Kajang and Nilai stations were mostly expected coming from transboundary sources especially biomass burning and the development activities around the study areas.     

A comparative study of biopolymers and alum in the separation and recovery of pulp fibres from paper mill effluent by flocculation

Recovery of cellulose fibres from paper mill effluent has been studied using common polysacchatides or biopolymers such as Guar gum, Xanthan gum and Locust bean gum as flocculent. Guar gum is commonly used in sizing paper and routinely used in paper making. The results have been compared with the performance of alum, which is a common coagulant and a key ingredient of the paper industry. Guar gum recovered about 3.86 mg/L of fibre and was most effective among the biopolyrners. Settling velocity distribution curves demonstrated that Guar gum was able to settle the fibres faster than the other biopolymers; however, alum displayed the highest particle removal rate than all the biopolymers at any of the settling velocities. Alum, Guar gum, Xanthan gum and Locust bean gum removed 97.46%, 94.68%, 92.39% and 92.46% turbidity of raw effluent at a settling velocity of 0.5 cm/min, respectively. The conditions for obtaining the lowest sludge volume index such as pH, dose and mixing speed were optimised for guar gum which was the most effective among the biopolymers. Response surface methodology was used to design all experiments, and an optimum operational setting was proposed. The test results indicate similar performance of alum and Guar gum in terms of fioc settling velocities and sludge volume index. Since Guar gum is a plant derived natural substance, it is environmentally benign and offers a green treatment option to the paper mills for pulp recycling.     

The role of disinfectants and sanitizers during COVID-19 pandemic: advantages and deleterious effects on humans and the environment

Environmental Science and Pollution Research - Disinfectants and sanitizers are essential preventive agents against the coronavirus disease 2019 (COVID-19) pandemic; however, the pandemic crisis...     

Assessing the life cycle study of alternative earth-retaining walls from an environmental and economic viewpoint

Environmental Science and Pollution Research - This research aims to assess the sustainability of the most common earth-retaining walls (Gravity Walls and Cantilever Walls) in terms of...     

A research on conventional and modern algorithms for maximum power extraction from wind energy conversion system: a review

Environmental Science and Pollution Research - In the last few decades, wind energy has become a significant source of the renewable energy system, and it is essential to use wind energy for...     

Assessment of pesticide toxicity on earthworms using multiple biomarkers: a review

Environmental Chemistry Letters - Two million tonnes&nbsp;of pesticides are currently used globally to improve crop production, yet these pesticides induce adverse effects on soil quality and...     

Green synthesis of ZrO2 nanoparticles and nanocomposites for biomedical and environmental applications: a review

Environmental Chemistry Letters - Pollution and diseases such as the coronavirus pandemic (COVID-19) are major issues that may be solved partly by nanotechnology. Here we review the synthesis of...     

People’s attitude towards willingness-to-pay for environmental protection in Pakistan

Environmental Science and Pollution Research - Recent environmental research has found that people with higher incomes and in more developed countries are more willing to pay (WTP) to protect their...