Bioavailability and dissipation of fluridone under controlled conditions

Abstract

Bioavailability of fluridone, l‐methyl‐3‐phenyl‐5‐[3‐(trifluoromethyl) phenyl]‐4(1H)‐pyridinone, as affected by soil temperature, soil moisture regime, and duration of incubation was investigated in three soil types by grain sorghum (Sorghum bicolor [L.] Moench cv. Abu Sabien) chlorophyll bioassay. Initial loss of fluridone was rapid and dissipation followed first‐order kinetics under most of the incubation treatments investigated. Soil moisture, in general, had a greater impact than soil temperature on dissipation of fluridone. The herbicide dissipated faster at the fluctuating room temperature (18–24°C) than at the constant 10°C in Sonning sandy clay loam (O.M. = 1.2%) and Erl Wood sandy loam (O.M. = 2.5%) but not in Shropshire loamy peat (O.M. = 33%). In the two mineral soils, bioassay‐detectable residues from an initial rate of 1.00 μg/g were least (0.00 ‐ 0.10 μg/g) at 1/2 field capacity (FC) and greatest (0.16 ‐ 0.37 μg/g) at 1/4 FC, 400 days after treatment. At 10°C, the DT₅₀ values (days) at 1/4 FC and 1/2 FC were, respectively, 147 ± 16 and 69 ± 6 for Erl Wood soil, and 257 ± 28 and 51 ± 12 for Sonning soil. In Shropshire soil, concentrations of bioavailable fluridone were least at each bioassay date when soil moisture was maintained at FC, at both temperatures of incubation. At 10°C, herbicide concentrations in the organic soil from an initial rate of 10.00 μg/g were 0.95 and 4.69 μg/g, respectively, at FC and 1/4 FC.     

Evaluation of pollution load of Lahore Canal by quantification of various pollutants through physicochemical characterisation

The work describes the physicochemical analysis of the water samples collected from Lahore Canal to evaluate pollution load at different points of the canal. Different physical and chemical pollutants such as temperature, pH, electrical conductivity, total dissolved and suspended solids, turbidity, chlorides, sulphates, nitrates, oils and grease, dissolved oxygen, chemical oxygen demand and biological oxygen demand (BOD) were analysed. The data was analysed through analysis of variance, which showed that the p values for dissolved oxygen (DO), chemical oxygen demand (COD), BOD, electrical conductivity, total dissolved solid (TDS), total suspended solid (TSS), turbidity, oil and grease, sulphates, and nitrates are <0.05, while p value of temperature, pH, and chlorides are 1.000, 0.984, and 0.070, respectively, which are >0.05. Further regression analysis revealed that the simple line regression modal is fit for turbidity and TSS, electrical conductivity and TDS, COD and DO, BOD and DO, and BOD and COD. The studies reveal that Lahore Canal is receiving a considerable amount of physical and chemical pollutants at different points.     

House fly (Musca domestica): A review of control strategies for a challenging pest

Musca domestica L. (Diptera: Muscidae), commonly called the house fly, is a major domestic, medical and veterinary pest that causes irritation, spoils food and acts as a vector for many pathogenic organisms. In this paper, the social and health problems related to housefly are introduced with the associated need to control its population. Physical and chemical methods of house fly control are briefly discussed. The main focus of this review is on the biological control methods for house fly control, that comprise botanical, fungal, bacterial and parasitoid agents. Although several biocontrol agents are still in the nascent stage, some of them (especially fungal and parasitoid agents) have shown reliable field performance and seem to be suitable candidates for commercialization. However, the majority of these laboratory and field studies have been conducted in the temperate region. It remains to be seen whether the application of biocontrol agents would be feasible in tropical environments. The integrated pest management practices, which can provide more reliable field performance, have also been discussed. A multi-dimensional approach that exerts control on all the life stages of house fly, but simultaneously preserves the fly's natural enemies could be an ecologically sustainable way of maintaining the fly populations below maximally acceptable limits.     

Fluoride Concentration in Drinking Water of Karachi City (Pakistan)

The ground and municipal water supply samples of Karachi city were analyzed for their fluoride contents. The fluoride contents in water samples collected from the subsurface and river sources were found below the WHO recommended value for the general health of the people. However, in some industrial areas the groundwater sample showed higher level of fluoride concentration. Continuous monitoring of water resources and cautious fluoridation is suggested to maintain proper status of fluoride concentration in the drinking water.     

Characterization and optimization of conditions for biodegradation of sella-rice mill effluent

The sella-rice mill effluent is a major environmental pollutant requiring proper treatment before disposal. The present study has been conducted to isolate and characterize micro-organisms capable of growing on sella-rice effluent and to optimize conditions for its rapid bioremediation. Using three different types of media (LB, YEPDA and PDA), a total of 139 isolates were isolated from effluent samples collected from three different locations. Out of these, 45 isolates were found to utilize starch on starch medium, eight isolates showing high efficiency. For the optimization of conditions for maximum utilization of starch by selected isolates, parameters such as effect of addition of carbon and nitrogen sources, effect of growth factors, temperature and pH were studied. Maximum growth (absorbance of 2.10) and starch-utilization (varying in the range of 2.33 to 3.62) was observed on starch medium supplemented with peptone and yeast extract at 30 degrees C with a pH of 6.0. These bacterial isolates also reduced the amount of starch (80.10%), BOD (64.24%) and COD (75.0%) of sella-rice mill effluent after 15 days of incubation. On the basis of morphological and biochemical characteristics, the selected isolates were found to belong to the genera Lactobacillus and Micrococcus.     

Influence of lead on growth and nutrient accumulation in canola (Brassica napus L.) cultivars

Canola (Brassica napus L.) is commonly used as a hyper-accumulator for phytoextraction of heavy metals from soil and water. Like many other heavy metals, lead (Pb) contaminates soil, water and air and thus it is a great problem. This study was conducted to investigate toxic effects of Pb on growth and nutrient uptake in four canola cultivars. Each of four cultivars of canola (Con-II, Con-III, Legend and Shiralee) was subjected to four levels of Pb (0, 30, 60 and 90 mg Pb kg(-1) of soil) from lead chloride [PbCl2]. Due to Pb toxicity, plant growth was adversely affected and relatively a severe reduction in root biomass (45.7%) was recorded. The Pb accumulation increased both in shoot and root, the highest being in root. The uptake of different nutrients, i.e., N, P, K, Ca, Mg, Zn, Cu and Mn was reduced (38.4, 32.8, 33.1, 49.6, 7.78, 52.0, 42.6 and 45.9%, respectively) in the shoots and that of N, Fe, Zn, and Cu in the roots (48.5, 33.2, 24.3 and 44.8%, respectively) of all canola cultivars. The root K, P, Zn and Mn and shoot P, Mg and Fe contents were less affected, the concentration of Pb, Ca and Mg in roots of all cultivars. Among canola cultivars Con-II and Con-III performed better than Legend and Shiralee in terms of growth (26.03%) and nutrient accumulation. Overall, plant growth and nutrient accumulation in the canola cultivars was hampered due to the presence of Pb.     

Estimation of bacteriological levels in surface water samples to evaluate their contamination profile

The present work deals with the assessment of bacteriological contamination along with some physico-chemical parameters of water samples from Lahore canal. ANOVA showed that the observed p values of log-transformed viable plate counts, total suspended solids, turbidity, and biological oxygen demand are 0.000, 0.000, 0.000, and 0.000, respectively, which are <0.05, while the p value of total coliforms, total fecal coliforms, and Escherichia coli are 0.728, 0.827, and 0.081, respectively which are >0.05. Significant correlation was observed between log-transformed viable plate counts (CFU), biological oxygen demand, total suspended solids, and turbidity. Further regression analysis revealed that simple line regression model is fit for log-transformed viable plate counts and total suspended solids, log-transformed viable plate counts and turbidity, turbidity and total suspended solids, biological oxygen demand and total suspended solids, biological oxygen demand and log-transformed viable plate counts, and biological oxygen demand and turbidity.     

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.     

Environmental exposure to urinary Bisphenol-A in North Indian children aged between 6 and 16 years and its association with body mass index

Environmental Science and Pollution Research - This study investigates the effect of environmental risk factors among North Indian children aged between 6 and 16 years associated with body mass...