Heavy metals distribution and risk assessment in soils affected by tannery effluents

Effluents collected from tanneries in Sialkot showed considerably higher levels of heavy metals. Sodium (12 660.91 mg/L) among macronutrients and Cr (592.20 mg/L) among heavy metals were found in the highest concentrations. Effluent parameters, i.e. biological oxygen demand (BOD; 12.40), chemical oxygen demand (COD; 16.53), Cd (5.90), Cr (592.20) and Fe (18.59) were the respective times higher than Pakistan National Environmental Quality Standards and their continuous unchecked discharge into agricultural soils poses a potential risk. Mean concentrations (mg/L) of Cr (592.20), Ni (2.66), Mn (1.16), Fe (37.17), Zn (0.90), Cd (0.59) and Pb (1.18) in this study exceeded levels recorded to date from different tanning hubs in Pakistan. Factor analysis/principal components analysis (FA/PCA) for the effluent parameters resulted in six varimax factors, i.e. VF1 (salinity, electrical conductivity, total dissolved solids, chloride, phosphate, BOD and COD; including characteristic tannery effluent features), VF2 (pH, Cr and alkalinity; tanning operations), VF3 (Cd and Pb; dyeing processes), VF4 (Mn and Fe; finishing operations), VF5 (Ni; retaining processes) and VF6 (hardness, Ca and Cu; bating processes). Cluster analysis performed on metal data resulted in three clusters confirming metal–metal relations obtained either from FA/PCA or a correlation matrix. The results of this study are useful for heavy metal source apportionment, assessment of risk to peripheral soils and the future management of environments around tanneries.     

Temporal variation in leachate composition of a newly constructed landfill site in Lahore in context to environmental pollution and risks

Environmental Science and Pollution Research - This study investigated the seasonal and temporal variations in the extent and source of physiochemical and toxic trace elements in the Lakhodair...     

Spatio-temporal variations in water quality of Nullah Aik-tributary of the river Chenab, Pakistan

This study reports the spatio-temporal changes in water quality of Nullah Aik, tributary of the Chenab River, Pakistan. Stream water samples were collected at seven sampling sites on seasonal basis from September 2004 to April 2006 and were analyzed for 24 water quality parameters. Most significant parameters which contributed in spatio-temporal variations were assessed by statistical techniques such as Hierarchical Agglomerative Cluster Analysis (HACA), Factor Analysis/Principal Components Analysis (FA/PCA), and Discriminant Function Analysis (DFA). HACA identified three different classes of sites: Relatively Unimpaired, Impaired and Less Impaired Regions on the basis of similarity among different physicochemical characteristics and pollutant level between the sampling sites. DFA produced the best results for identification of main variables for temporal and spatial analysis and separated eight parameters (DO, hardness, sulphides, K, Fe, Pb, Cr and Zn) that accounted 89.7% of total variations of spatial analysis. Temporal analysis using DFA separated six parameters (E.C., TDS, salinity, hardness, chlorides and Pb) that showed more than 84.6% of total temporal variation. FA/PCA identified six significant factors (sources) which were responsible for major variations in water quality dataset of Nullah Aik. The results signify that parameters identified by statistical analyses were responsible for water quality change and suggest the possibility of industrial, municipal and agricultural runoff, parent rock material contamination. The results suggest dire need for proper management measures to restore the water quality of this tributary for a healthy and promising aquatic ecosystem and also highlights its importance for objective ecological policy and decision making process.     

Quantification of polychlorinated biphenyl contamination using human placenta as biomarker from Punjab Province,Pakistan

Environmental Science and Pollution Research - The present study biomonitored the placental polychlorinated biphenyl (PCB) concentrations in women from Punjab Province, Pakistan, that provides the...     

Source evaluation of physicochemically contaminated groundwater of Dera Ismail Khan area, Pakistan

Groundwater samples collected from Dera Ismail Khan, Pakistan, in 15 different stations were analyzed to determine the status of concentration of different physicochemical parameters. The samples were collected around a sugar mill in the study area. Sample location was selected on the basis of the flow of sugar mill effluents and groundwater. The samples were collected at random intervals in different villages. The physicochemical parameters such as pH, electrical conductivity (EC), total dissolved salts (TDS), TH, HCO₃, NO₃, SO₄, PO₄, Na, K, Ca, Mg, Fe, F, and Pb have been analyzed. The results showed that values of the tested parameters for EC, TDS, TH, HCO₃, SO₄, and Na near the sugar mill were very high, which indicate the descent of standard norms of quality and protection procedures for the groundwater around this area.     

Microplastics in water,sediments, and fish at Alpine River,originating from the Hindu Kush Mountain,Pakistan: implications for conservation

Environmental Science and Pollution Research - Microplastics (MP) pollution is an emerging threat to life and the environment. These particles are not restricted to human-inhabited lands but also...     

Sonochemically induced decomposition of energetic materials in aqueous media

This study demonstrates that ultrasound rapidly degrades the energetic compounds RDX (cyclo-1,3,5-trinitramine-2,4,6-trimethylene) and ADN (ammonium dinitramide) in aqueous microheterogeneous media. The conditions for effective degradation of these nitramines, as monitored by UV absorption spectroscopy, were determined by varying sonication time, the heterogeneous phase and its suspension density, and the concentration of NaOH. In the presence of 5 mg/ml of aluminum powder and at pH approximately 12 (10 mM NaOH), 74% of the RDX and 86% of the ammonium dinitramide (ADN) in near-saturated solutions decompose within the first 20 min of sonication (20 kHz; 50 W; < or =5 degrees C). Sonication without Al powder and base yields minimal degradation of either RDX and ADN (approximately 5-10%) or the nitrite/nitrate ions that are expected byproducts during RDX and ADN degradation. Sonication at high pH in the presence of dispersed aluminosilicate zeolite, alumina, or titanium dioxide also yields minimal degradation. Preliminary electrochemical studies and product analyses indicate that in situ ultrasonic generation of metallic aluminum and/or aluminum hydride drives reductive denitration of the nitramines. Sonochemical treatment in the presence of a reductant offers an effective and rapid waste remediation option for energetic waste compounds.     

Salt-induced land and water degradation in the Aral Sea basin: A challenge to sustainable agriculture in Central Asia

Expansion of irrigated agriculture in the Aral Sea Basin in the second half of the twentieth century led to the conversion of vast tracks of virgin land into productive agricultural systems resulting in significant increases in employment opportunities and income generation. The positive effects of the development of irrigated agriculture were replete with serious environmental implications. Excessive use of irrigation water coupled with inadequate drainage systems has caused large‐scale land degradation and water quality deterioration in downstream parts of the basin, which is fed by two main rivers, the Amu‐Darya and Syr‐Darya. Recent estimates suggest that more than 50% of irrigated soils are salt‐affected and/or waterlogged in Central Asia. Considering the availability of natural and human resources in the Aral Sea Basin as well as the recent research addressing soil and water management, there is cause for cautious optimism. Research‐based interventions that have shown significant promise in addressing this impasse include: (1) rehabilitation of abandoned salt‐affected lands through halophytic plant species; (2) introduction of 35‐day‐old early maturing rice varieties to withstand ambient soil and irrigation water salinity; (3) productivity enhancement of high‐magnesium soils and water resources through calcium‐based soil amendments; (4) use of certain tree species as biological pumps to lower elevated groundwater levels in waterlogged areas; (5) optimal use of fertilizers, particularly those supplying nitrogen, to mitigate the adverse effects of soil and irrigation water salinity; (6) mulching of furrows under saline conditions to reduce evaporation and salinity buildup in the root zone; and (7) establishment of multipurpose tree and shrub species for biomass and renewable energy production. Because of water withdrawals for agriculture from two main transboundary rivers in the Aral Sea Basin, there would be a need for policy level interventions conducive for enhancing interstate cooperation to transform salt‐affected soil and saline water resources from an environmental and productivity constraint into an economic asset.     

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...     

Economics of salt‐induced land degradation and restoration

Food security concerns and the scarcity of new productive land have put productivity enhancement of degraded lands back on the political agenda. In such a context, salt‐affected lands are a valuable resource that cannot be neglected nor easily abandoned even with their lower crop yields, especially in areas where significant investments have already been made in irrigation and drainage infrastructure. A review of previous studies shows a very limited number of highly variable estimates of the costs of salt‐induced land degradation combined with methodological and contextual differences. Simple extrapolation suggests that the global annual cost of salt‐induced land degradation in irrigated areas could be US$ 27.3 billion because of lost crop production. We present selected case studies that highlight the potential for economic and environmental benefits of taking action to remediate salt‐affected lands. The findings indicate that it can be cost‐effective to invest in sustainable land management in countries confronting salt‐induced land degradation. Such investments in effective remediation of salt‐affected lands should form part of a broader strategy for food security and be defined in national action plans. This broader strategy is required to ensure the identification and effective removal of barriers to the adoption of sustainable land management, such as perverse subsidies. Whereas reversing salt‐induced land degradation would require several years, interim salinity management strategies could provide a pathway for effective remediation and further showcase the importance of reversing land degradation and the rewards of investing in sustainable land management.