Search

A long-term energy crisis has resulted in increased combustion of biomass fuel in industrial and household sectors in Pakistan. We report results of a study on the emission characteristics of rice husk, rice straw, corncobs and bagasse since they are frequently used as biomass fuel and differed remarkably in physico-chemical and combustion characteristics. Emission concentrations and emission factors were determined experimentally by burning the biomass fuel using a burning tower. Modified combustion efficiency (MCE) of rice husk, rice straw, corncobs and bagasse was >0.97 indicating that combustion was dominated by flaming mode. Emission factors of gaseous pollutants CO, CO2, NO2, NO, NO x and SO2 for rice straw were calculated to be 17.19 ± 0.28, 1090.07 ± 24.0, 0.89 ± 0.03, 1.48 ± 0.04, 3.16 ± 0.08 and 0.38 ± 0.03 g kg−1 respectively which were significantly (p < 0.05) higher compared to those from rice husk (14.05 ± 0.18, 880.48 ± 8.99, 0.19 ± 0.01, 1.38 ± 0.02, 2.31 ± 0.04 and 0.11 ± 0.03 g kg−1), corncobs (8.63 ± 0.12, 595.44 ± 10.38, 0.16 ± 0.01, 0.70 ± 0.01, 1.23 ± 0.02 and 0.02 ± 0.00 g kg−1) and bagasse (12.39 ± 0.08, 937.03 ± 9.07, 0.36 ± 0.03, 1.44 ± 0.02, 2.57 ± 0.04 and 0.18 ± 0.02 g kg−1). Total emissions of CO, CO2, NO2, NO, NO x and SO2 were estimated to be 3.68, 230.51, 0.05, 0.36, 0.60 and 0.03 Gg for rice husk, 33.75, 2140.35, 1.75, 2.91, 6.20 and 0.75 Gg for rice straw, 1.11, 76.28, 0.02, 0.02 and 0.03 Gg for corncobs and 42.12, 3185.53, 1.22, 4.90, 8.74 and 0.61 Gg for bagasse respectively. Rice straw, however, had significantly (p < 0.05) higher potential of gaseous pollutant emission factors. Bagasse had the highest values of total emissions followed by rice straw, rice husk and corncobs. Rice straw and bagasse, on cumulative basis, contributed more than 90% of total emissions of gaseous pollutants. Results reported in this study are important in formulating provincial and regional emission budgets of gaseous pollutants from burning of agricultural residues in Pakistan. [ABSTRACT FROM AUTHOR]

Spices are an essential part of our food preparations and are considered a potential source of health-protective components. However, spices may also contain some toxic substances primarily aflatoxins and heavy metals. This study aimed to quantify the level of total aflatoxins and three most toxic heavy metals i.e. lead (Pb), arsenic (As) and cadmium (Cd) in commercially available non-branded and branded spices. Furthermore, risk assessment through aflatoxins and heavy metals was performed by computing the values of Margin of Exposure (MOE) and Total Hazard Quotient (THQ), respectively. The concentration of aflatoxins was recorded higher in non-branded spices while heavy metals especially Pb was recorded higher in branded spices. MOE values for aflatoxins through spices consumption indicated that all age group of people were consuming aflatoxins above the threshold level. The THQ values for heavy metals toxicity assessment were found within the acceptable ranges. Females, especially above 24 years of age, were found at more risk as compared to male, due to their higher intake rate of spices. • Aflatoxins and heavy metals were quantified in branded and non-branded spices. • Branded spices were found less contaminated as compared to non-branded. • Margin of Exposure values indicated the chances of toxicity in all age groups. • Total Hazard Quotient values for heavy metals were found within safe ranges. [ABSTRACT FROM AUTHOR]

Chromium (Cr) is among the most widespread toxic trace elements found in agricultural soils resulting from various anthropogenic activities. However, the role of micronutrient-amino acid chelates in reducing Cr toxicity in crop plants has recently been suggested. The present study was conducted to explore the effect of iron (Fe) chelated with lysine (lys) on plant growth, biomass, gaseous exchange attributes, oxidative stress indicators, antioxidant response, and Cr uptake in rapeseed (Brassica napus L.) plants irrigated with different levels of tannery wastewater in soil collected from District Kasur of Pakistan. B. napus seedlings (thirty-day-old) were shifted to pots irrigated with different levels of tannery wastewater. After two weeks, foliar application of Fe–lys (5 mM) was carried out for four successive weeks, and plants were harvested carefully post ten weeks of cultivation in tannery wastewater, under controlled conditions. Toxic levels of Cr in the soil significantly decreased plant height, fresh biomass of roots and leaves, dry biomass of roots and leaves, root length, number of leaves, leaf area, total chlorophyll contents, carotenoid contents, transpiration rate (E), stomatal conductance (g s), net photosynthesis (P N), and water use efficiency (WUE). Toxic Cr levels in the soil also increased oxidative stress in the roots and leaves of B. napus plants, which were overcome by the activities of various antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Moreover, increasing levels of Cr in the soil caused a significant increase in the Cr content of the roots and shoots of B. napus plants. The negative effects of Cr toxicity could be overturned by Fe–lys application, significantly increasing plant growth, biomass, chlorophyll content, and gaseous exchange attributes by reducing oxidative stress (H 2 O 2 , MDA, EL) and enhancing antioxidant enzyme activities. Furthermore, foliar application of Fe–lys reduced the Cr concentration and increased essential micronutrients (Fe contents) in the roots and shoots of B. napus plants. These results shed light on the effectiveness of Fe–lys in improving the growth and up-regulation of antioxidant enzyme activities of B. napus in response to Cr stress. However, further studies at field levels are required to explore the mechanisms of Fe–lys-mediated reduction of the toxicity of not only Cr, but possibly also other heavy metals in plants. Image 1 • Cr toxicity reduced morpho-physiological traits of B. napus plant when cultivated in tannery wastewater. • Cr toxicity also induced oxidative stress in the plant. • Application of Fe-lys alleviates Cr toxicity. • Application of Fe-lys also increased Fe contents while decreased Cr contents. [ABSTRACT FROM AUTHOR]

The scientific progress in space research indicates earthquake-related processes of surface temperature growth, gas/aerosol exhalation and electromagnetic disturbances in the ionosphere prior to seismic activity. Among them surface temperature growth calculated using the satellite thermal infrared images carries valuable earthquake precursory information for near/distant earthquakes. Previous studies have concluded that such information can appear few days before the occurrence of an earthquake. The objective of this study is to use MODIS thermal imagery data for precursory analysis of Kashmir (Oct 8, 2005; M w 7.6; 26 km), Ziarat (Oct 28, 2008; M w 6.4; 13 km) and Dalbandin (Jan 18, 2011; M w 7.2; 69 km) earthquakes. Our results suggest that there exists an evident correlation of Land Surface Temperature (thermal; LST) anomalies with seismic activity. In particular, a rise of 3–10 °C in LST is observed 6, 4 and 14 days prior to Kashmir, Ziarat and Dalbandin earthquakes. In order to further elaborate our findings, we have presented a comparative and percentile analysis of daily and five years averaged LST for a selected time window with respect to the month of earthquake occurrence. Our comparative analyses of daily and five years averaged LST show a significant change of 6.5–7.9 °C for Kashmir, 8.0–8.1 °C for Ziarat and 2.7–5.4 °C for Dalbandin earthquakes. This significant change has high percentile values for the selected events i.e. 70–100% for Kashmir, 87–100% for Ziarat and 84–100% for Dalbandin earthquakes. We expect that such consistent results may help in devising an optimal earthquake forecasting strategy and to mitigate the effect of associated seismic hazards. [ABSTRACT FROM AUTHOR]

• Biochars had higher total CNPK contents than their feedstocks. • FYM and FYM-B resulted in the highest grain yield and KUE. • Biochars were more effective to enhance maize productivity and SOC content. • Increase in soil K and SOC contents showed positive effects on maize productivity. The contemporary exhaustive agriculture has led to drastic reductions in soil potassium (K) status because of constant soil K mining by crops without sufficient recharge through external K inputs. Therefore, substituting and/or supplementing K through alternative sources has great prospects in developing countries like Pakistan, where imported K fertilizers are comparatively expensive. This two-year field study reports the effects of alternative sources of K as farmyard manure (FYM), sugarcane bagasse and woodchip, and their biochars (B) i.e. FYM-B, bagasse-B and woodchip-B on soil fertility, K availability, K use efficiency (KUE), soil organic carbon (SOC) and maize productivity in calcareous soil of the semiarid northern region of Pakistan. Alternative sources of K and their biochars were applied along mineral K fertilizer as muriate of potash (KCl) at 60 kg ha−1 rate in a randomized complete block design. Results showed that FYM–B significantly increased plant height, grains per cob and 1000-grain weight. The FYM–B increased grain yield by 6.5, 37.2, and 87.0% when compared with woodchip–B, chemical fertilizer and control treatments, respectively. Similarly, FYM–B and woodchip–B significantly increased SOC and soil available K contents as compared with the rest of the treatments. Grain K contents and KUE were generally higher in biochar than their feedstock treatments during both years. However, FYM–B resulted in significantly higher KUE compared to the other K sources and their biochars during both years. The biological and grain yields showed significant positive correlations with soil K and SOC contents. Our study concluded that FYM and FYM-B can be applied as alternative and/or supplementary K sources along woodchip-B and bagasse-B to improve maize productivity, KUE and SOC contents in nutrient poor soil. However, economic feasibility of such practices is required to be priorly investigated on long-term basis. [ABSTRACT FROM AUTHOR]