An alternative approach to reconstructing organic matter accumulation with contrasting watershed disturbance histories from lake sediments

A number of proxies, including carbon to nitrogen ratio (C:N) and stable isotopes (delta(13)C and delta(15)N), have been used to reconstruct organic matter (OM) profiles from lake sediments and these proxies individually or in combination cannot clearly discriminate different sources. Here we present an alternative approach to elucidate this problem from lake sediments as a function of watershed scale land use changes. Stable isotope signatures of defined OM sources from the study watersheds, Shawnigan Lake (SHL) and Elk Lake (ELL), were compared with sedimentary proxy records. Results from this study reveal that terrestrial inputs and catchment soil coinciding with the watershed disturbances histories probably contributed in recent trophic enrichment in SHL. In contrast, cultural eutrophication in ELL was partially a result of input from catchment soil (agricultural activities) with significant input from lake primary production as well. Results were consistent in both IsoSource (IsoSource version 1.2 is a Visual Basic program used for source separation, (http://www.epa.gov/wed/pages/models/isosource/isosource.htm) and discriminant analysis (statistical classification technique).     

Rooting response in stem cuttings from five species of mangrove trees: effect of auxins and enzyme activities

An experiment was conducted to optimise rooting in stem cuttings of the mangrove tree species Bruguiera parviflora, Cynometra iripa, Excoecaria agallocha, Heritiera fomes and Thespesia populnea. Cuttings were girdled or non-girdled and treated with the auxins indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and naphthalene-acetic acid (NAA) and amylase, IAA-oxidase, peroxidase and polyphenol oxidase activities were measured. The best rooting performance (in terms of root number) was in stem cuttings of E. agallocha followed by C. iripa and H. fomes when treated with IBA + NAA. IAA and IBA combinations were more effective in T. populnea and B. parvifolia. Variations in rooting response were markedly reflected in amylase, IAA-oxidase, peroxidase and polyphenol oxidase activities. Sharp increases in amylase and polyphenol-oxidase activities were associated with enhanced rooting in E. agallocha, C. iripa and H. fomes. On the contrary, lowered IAA-oxidase and peroxidase activities favoured rooting in T. populnea and B. parviflora. A higher number of roots occurred in pre-girdled cuttings in comparison to non-girdled cuttings. Received: 30 March 1999 / Accepted: 6 October 1999     

<Emphasis Type="Bold">Tracing lead contamination in foods in the city of Kolkata,India</Emphasis>

Lead isotopic ratios (LIR) of eight common food items, street dust, coal, diesel, sediments, lead ore and rainwater from India have been reported for the first time in this paper. This study characterized the source and extent of lead pollution in the different foodstuff consumed in Kolkata, a major metropolis of eastern India. The atmospheric lead input to the food items, sold openly in busy roadside markets of the city, has been quantified. The mean 207/206 and 208/206 LIRs of the eight food items ranged from 0.8847 to 0.8924 and 2.145 to 2.167, respectively. Diesel had the highest mean 207/206 and 208/206 values of 0.9015 and 2.1869, respectively, apart from the lead ore. The food items had a mean lead concentration between 3.78 and 43.35 mg kg^?1. The two ratio scatter plots of all the different environmental matrices were spread linearly between the uncontaminated Ichapur sediment and diesel. The 207/206 LIRs of the coal with a mean of 0.8777 did not fall in the linear trend, while the street dust and food samples overlapped strongly. The rainwater sample had a 207/206 LIR of 0.9007. Contaminated sediments in Dhapa, the repository of the city’s municipal garbage, had a mean 207/206 LIR of 0.8658. The corresponding value obtained from the sewage-fed vegetable grown there was 0.8058. The present study indicated that diesel was one of the main contributor to Pb pollution. The atmospheric lead contribution to the food items was in the range of 68.48–86.66 %.     

Characterization and cadmium-resistant gene expression of biofilm-forming marine bacterium Pseudomonas aeruginosa JP-11

Biofilm-forming marine bacterium Pseudomonas aeruginosa JP-11 was isolated from coastal marine sediment of Paradeep Port, Odisha, East Coast, India, which resisted up to 1,000 ppm of cadmium (Cd) as cadmium chloride in aerobic conditions with a minimal inhibitory concentration of 1,250 ppm. Biomass and extracellular polymeric substances (EPS) secreted by the cells effectively removed 58.760?±?10.62 and 29.544?±?8.02 % of Cd, respectively. The integrated density of the biofilm-EPS observed under fluorescence microscope changed significantly (P?≤?0.05) in the presence of 50, 250, 450, 650 and 850 ppm Cd. ATR-FTIR spectroscopy showed a peak at 2,365.09/cm in the presence of 50, 250, 450 and 650 ppm Cd which depicts the presence of sulphydryl group (–SH) within the EPS, whereas, a peak shift to 2,314.837/cm in the presence of 850 ppm Cd suggested the major role of this functional group in the binding with cadmium. On exposure to Cd at 100, 500 and 1,000 ppm, the expression profiles of cadmium resistance gene (czcABC) in the isolate showed an up-regulation of 3.52-, 17- and 24-fold, respectively. On the other hand, down-regulation was observed with variation in the optimum pH (6) and salinity (20 g l^?1) level. Thus, the cadmium resistance gene expression increases on Cd stress up to the tolerance level, but an optimum pH and salinity are the crucial factors for proper functioning of cadmium resistance gene.     

A semi-automated tool for identifying agricultural roadway crashes in crash narratives

Objective: Crash reports contain precoded structured data fields and a crash narrative that can be a source of rich information not included in the structured data. The narrative can be useful for identifying vulnerable roadway users, such as agricultural workers. However, using the narratives often requires manual reviews that are time consuming and costly. The objective of this research was to develop a simple and relatively inexpensive, semi-automated tool for screening crash narratives and expediting the process of identifying crashes with specific characteristics, such as agricultural crashes.

Methods: Crash records for Louisiana from 2010 to 2015 were obtained from the Louisiana Department of Transportation (LaDOTD). Records with narratives were extracted and stratified by vehicle type. The majority of analyses focused on a vehicle type of farm equipment (Type T). Two keyword lists, an inclusion list and an exclusion list, were created based on the published literature, subject-matter experts, and findings from a pilot project. Next, a semi-automated tool was developed in Microsoft Excel to identify agricultural crashes. Lastly, the tool’s performance was assessed using a gold standard set of agricultural narratives identified through manual review.

Results: The tool reduced the search space (e.g., number of narratives that need manual review) for narratives requiring manual review from 6.7 to 59.4% depending on the research question. Sensitivity was high, with 96.1% of agricultural crash narratives being correctly classified. Of the gold standard agricultural narratives, 58.3% included an equipment keyword and 72.8% included a farm equipment brand.

Conclusion: This article provides information on how crash narratives can supplement structured crash data. It also provides an easy-to-implement method to facilitate incorporating narratives into safety research along with keyword lists for identifying agricultural crashes.     

Essential oils and their bioactive compounds as eco-friendly novel green pesticides for management of storage insect pests: prospects and retrospects

Environmental Science and Pollution Research - The control of storage insect pests is largely based on synthetic pesticides. However, due to fast growing resistance in the targeted insects,...     

Riverbank stabilization based on the modulation of the near bank turbulence scales

Environment, Development and Sustainability - Sundarban area of the lower Gangetic plain experiences embankment failure almost every year due to the formation of toe undercuts. Waves generated due...     

Assessment of Ergonomic and Occupational Health-Related Problems Among Female Prawn Seed Collectors of Sunderbans,West Bengal,India

Abstract

Sixty female prawn seed collectors and 60 female control subjects from Sajenakhali and Sandeshkhali blocks of Sunderbans, West Bengal, India, were randomly selected to evaluate and compare musculoskeletal disorders and physiological stress. The control group was engaged in domestic work involving minimum hand-intensive activities. The modified Nordic musculoskeletal questionnaire and rapid entire body assessment were used. Most subjects suffered from discomfort in different body parts, especially in the lower back (98%), knees (88%), shoulders (75%), ankles (70%) and feet (67%). This study reveals that female prawn seed collectors suffer from significant physiological load and extreme physiological stress due to prolonged working hours in a standing posture and excessive work pressure. Consequently, all these factors affect female prawn seed collectors ‘ health and work performance.     

Environmental variables and fisheries diversity of the Naaf River Estuary,Bangladesh

The Naaf River estuary is one of the large estuaries in the Bangladesh coastal region not to have been affected by extensive human disturbance. This research provides information about the fisheries diversity status by Estuarine Set Bag Net (ESBN) sampling relation to physicochemical variables in both spatio-temporal scales. About 25 km of the lower estuary was divided into six zones for sample collection by considering the accessibility and availability of the ESBN operation, fish landing centers and location of the fishing villages. In total 48 samples have been analyzed which were taken throughout March to October 2006. To quantify the species diversity, all fisheries data were analyzed by using EstimateS and EcoSim software which accounts the different diversity indices viz., species richness, Shannon–Wiener diversity Index, Dominance and Evenness index. The research results demonstrate that the Naaf River estuary is a habitat of 161 (species richness, Sobs = 161, Choa 1 = 162 ± 2.34, ACE = 161.73) different species which belong to 98 fin fishes, 23 shrimps and prawns, 13 crabs, 11 molluscs, 3 echinoderms, 4 other crustaceans; while 9 remain unidentified. Results on the aquatic environment, mainly salinity and turbidity were found to have a major influence on their occurrence and distribution. All the findings indicated that the Naaf River estuary is a highly productive system and provides a favourable environment for large variety of estuarine species assemblages.