Bio-availability and Bio-accessibility of Lead and Zinc in Contaminated Soil from Cwymystwyth Lead Mine Site

Cwmystwyth Lead Mine was an abundant mine site with pugh’s and kingside water drainages shows contaminated water in the research area with no much scientific evidence to ascertain the level of the pollution. Hence this research was designed to study level of lead and zinc in contaminated soil in which the bio-availability and bio-accessibility were measured. Sixteen (16) soil samples were taken at random using soil auger and a hand trowel. The samples were dried using an oven set at a constant temperature of 400oC for 72 hours. Wire mesh (250 microns) was used to sift the samples. The Unified (BARGE) method was used. The mimics mixtures of saliva, gastric, duodenal, and bile fluids. Three-stage mimic processes were performed, in the mouth, the stomach and intestinal cavities. All mimic digestive fluids were placed in the rotator water bath for 1hr at 37oC. The bioaccessibility of the soil Samples were analyzed by inductively coupled plasma-optical emission spectrophotometer (ICP-OES) method. The results were obtained using XRF and ICP methods. The percentage concentration of lead in the topsoil was 0.64% and in the bottom soil was 1.47%, with a total mean concentration of 1.06% in combined top and bottom soil. Zinc concentrations in the top and bottom soils were 0.22 and 0.45%, respectively, with a computed total mean of 0.34%. The findings revealed a highly significant difference between lead and zinc in both the top and bottom soil samples (LSD = P0.05). The average concentrations of lead and zinc extracted in both the stomach and intestinal stages were 15.98% and 1.23%, respectively

Microalgae and Biochar Agro-Fertilization of the Palestinian Rehan Barley Cultivar under Salinity Stress

The efficient transfer of nutrients to plants in the form of biofertilizers on poor substrate was investigated. Biochar and dried algae biomass as well as mineral fertilizer were used to test the growth of the Palestinian ‘Rehan’ barley cultivar under salinity stress (4, 8, and 16 mS/cm EC). Rehan cultivar showed resilience to moderate levels of salinity and could still grow under high salinity stress (16 mS/cm EC). Rehan barley possessed better growth at early growth stage under the applied biofertilizers such as dried freshwater algal biomass (Chlorella vulgaris) and nutrient-laden biochar. It showed better growth than wheat (ssp. scirocco) under the same conditions. Its growth was highly improved by biochar treatment in low and moderate salinity conditions. Moreover, the combined effect between biochar and dried algae biomass could improve Rehan barley growth, but less than the effect of each biofertilizer separately. The biofertilizers affected most plant growth parameters under the salinity level of 4 and 8 mS/cm EC positively, while the growth declined again at 16 mS/cm EC. Overall, the biochar treatment showed the same effect as the mineral fertilizer on most of the parameters. The dried algae biomass and biochar also affected soil conditions. The highest soil water content (15.09%) was found in algae biomass treatments with 16 mS/cm EC. Biochar with 8 and 16 mS/cm EC had the highest pH value (8.63) near the rhizospheres. The nitrogen level was highest in the bottom soil sample (0.28 g N/kg soil) for biochar with 0 and 4 mS/cm EC. Meanwhile, the phosphate concentration was the highest (3.3 mg PO3−2/kg soil) in algae fertilizer treatments with 0 mS/cm EC in the bottom soil sample and lowest (4.14 mg PO3−2/kg soil) for the biochar with 8 mS/cm EC. The dried algae biomass and the biochar treatments can subsequently be viewed as conditioner substrates for improving the quality and fertility of the soil. Where possible, they should be considered as complement or replacement of mineral and manure fertilization to improve the impact on soil and environment.

Variation in Bottom Soil Quality with Increasing Pond Age in Freshwater Aquaculture

Pond bottom soil quality is an interesting area to assess environmental impact of aquaculture. Aim of the present study was, therefore, to investigate effects of fish culture on quality of pond bottom soil. Ten excavated earthen ponds located in Lahore, Pakistan were divided into two groups; Group1: 23-32 years old and Group 2: 8-20 years old ponds. Mechanical and chemical methods were used to study particle size distribution and physico-chemical attributes of soil respectively. Surface sediment of ponds contained higher sand and lower clay content than that of deeper soil layers in both groups. pH of the soil was higher than 7.0 that ruled out the necessity to lime soil for neutralizing acidity. Salinity of surface soil was found to be significantly high (P<.05) compared to that of deeper layers. Organic carbon in surface soil of Group 1 ponds (3.35%) was significantly higher (P<.05) than that of Group 2 ponds (2.60%). Available phosphorous represented only 1-10% of total soil phosphorous. An interactive effect of pond age and soil depth was found on soil clay and electrical conductivity through factorial analysis. Results led to the conclusion that regular removal of sediment can maintain original quality of bottom soil.

Bacteriological study of bottom soil of three extensive fish farm ponds

The study was conducted for bacteriological assessment of pond bottom soil (sediment) from three selected fish ponds of Bangladesh Agricultural University. Samples were collected both in winter and summer seasons to see the seasonal variations of some bacterial genera. Physicochemical parameters of the pond water and sediment were also estimated monthly. Sediment samples were collected from the shore and middle zone of the ponds. All sediment samples were acidic. The total viable count of bacteria in pond sediment ranged from (8.5×106) to (4.9×109) cfu/g and bacterial count were higher in summer than in winter. A total of 16 bacterial genera were identified from the sediments. The predominant microflora consisted of Aeromonas, Flavobacterium, Cytophaga, Escherichia, Bacillus, Micrococcus, Staphylococcus, Aerococcus, Acinetobacter, Pseudomonas and Moraxella while the first five listed the greatest abundance. Aeromonas was the most dominant organism. Bacterial diversification was found higher in summer than in winter.

Development of multistage plowing method that involves subsurface loosening

The paper proposes a new method for multistage plowing that implies loosening bottom soil and subsoil horizon simultaneously, followed by overturning the bottom soil without cutting, which improves the quality of soil cultivation, softens a plow sole and reduces energy costs. Experimental studies confirmed the theoretical relationship for determining the plowing resistance, both of certain working bodies of a section, and of a whole plow. The method proposed for multistage plowing that implies loosening the subsoil provides a decrease in plowing resistance by 8.3-9.8% compared to the existing double-depth plowing followed by loosening the subsoil.

GEOELECTRICAL SECTION OF THE BARGUZIN BAY OF LAKE BAIKAL ACCORDING TO GEORADAR AND RADIO IMPEDANCE SOUNDING DATA

Electrical resistivity (electrical conductivity) of water and bottom soil of the Barguzin Bay was studied by radio impedance soundings in VLF/LF bands, and the measurements were analysed. The georadar sounding method was used to investigate dielectric permittivity of freshwater ice (dielectric constant is ε=3.4). We developed the technique of radio impedance sounding from the ice surface of Lake Baikal for measuring the electrical resistance of bottom soil in the water area, and applied this technique to a layered model of a medium with a base showing poor/good conductivity. Geoelectric models were constructed for the Barguzin Bay coast and the southern Lake Baikal. The geoelectrical section (GES) of the water area can be useful for earthquake forecasting from electromagnetic data, as well as for analysing the physical and chemical causes of the occurrence of ring structures on the ice surface of Lake Baikal.

EFFECTS OF UNDERWATER LOW-FREQUENCY SOUND PROPAGATION THROUGH CONTINENTAL BARRIER

Обнаружены и исследованы подводный и донный низкочастотные акустические сигналы (400 Гц) от подводного источника излучения, расположенного относительно приемной системы по другую сторону перешейка мыса Шульца. Приемная система состояла из трехкомпонентного донного геофона и приемной акустической комбинированной системы, расположенной в толще волновода на глубине 9 м. Кратчайшее расстояние между источником и приемником через материковый барьер составляет ~ 1000 м. Азимутальный угол прихода сигнала продольных волн совпадает с геометрической линией, соединяющей источник и приемник. Прием поперечной и продольной волн осуществляется по различным ортогональным осям координат геофона. Направление прихода продольной волны в точку измерения близко к горизонтальному. Наличие поперечной волны в донном грунте позволяет предположить, что дно волновода представляет собой твердую жесткую поверхность. The present work studies the underwater and sea bottom low-frequency signals (400 Hz) emitted by the underwater transducer and detected by the receiver system located on the other side of the Schultz cape neck relative to the transducer. The receiver system consisted of a three-component bottom geophone and composite acoustical system immersed 9 m down the water column of the waveguide. The shortest distance between transducer and receiver through the continental barrier was ~1000 m. The azimuth angle of signal arrival corresponds to a geometrical line connecting a pair transducer/receiver. The reception of longitudinal and transverse waves was performed alongside different orthogonal axes of geophone coordinates. The direction of the longitudinal wave arrival at the reception point was close to horizontal. The presence of the transverse wave in the bottom soil suggests that the bottom of the waveguide represents a solid rigid surface.