Arsenic, a persistent and bio-accumulative poisonous element, has potential to pollute land, water, crops and the overall environment; ultimately affecting human and animal health. Arsenic has become a common contaminant in the environment and particularly ground water arsenic contamination has become a global issue. Higher concentrations of arsenic in the environment, due to its toxicity and induced carcinogenetic effect, is considered a serious problem for human health, especially in countries like Bangladesh, India, Vietnam, China, Canada, USA, Mexico and Chile. In Pakistan, a joint research conducted by PCRWR, UNICEF and National Water Quality Monitoring Program (2002-2006) revealed the presence of arsenic in Punjab and Sind provinces. According to PCRWR report (2005-2006), in Punjab out of 11559 ground water samples, 38% contained arsenic concentration more than permissible limit (>10 ppb), 17% contained >50 ppb and 4% contained >100 ppb. In Sindh out of 5991 samples, 11% contained arsenic concentration >10 ppb, 3% contained >50 ppb & 1.42% contained arsenic concentration > 100 ppb. Similarly, in another joint study conducted by Tokyo Institute of Technology and National Institute of Advanced Industrial Science and Technology (AIST), Pakistan, it was observed that the water samples in the Southern and other areas of Punjab had arsenic level up to five times higher than permissible limit (10 ppb) of the WHO standards. Significant research has been carried out to provide arsenic free drinking, municipal and industrial waste water using conventional techniques based on principles of precipitation-coagulation, oxidation, membrane separation, electro coagulation/flocculation and adsorption. The applicability of these procedures is limited on account of their high operational and capital costs, expensive reagents, high energy requirements, low selectivity and presence of interfering species from sludge and waste products. Among others, adsorption principle for arsenic remediation has been extensively exercised using a wide range of adsorbents. Adsorbents used may range from naturally occurring and synthetic minerals to agricultural products and wastes. Bio-sorbent like fungi, algae and bacteria are considered environment friendly and can be used as alternate sorbents. Bio-sorption is a passive immobilization of arsenic by biomass and cell surface sorption mechanisms are independent of cell metabolism. The process is based upon physicochemical interactions between arsenic and functional groups of the cell walls mainly composed of polysaccharides, lipids and proteins and other binding sites. The use of fungi for bioremediation of water contaminated with toxic compounds has gathered unusual attention as they are found everywhere in the natural environment and are mostly the dominant organisms, particularly over a wide range of pH. Cell walls of fungi contain sufficient quantities of polysaccharides and proteins, which contains a number of functional groups (such as hydroxyl, carboxyl, phosphate, sulphate, and amino groups) that help in binding of metal ions. Many fungal species such as Aspergillus fumigatus, Aspergillus niger, Penicillium sp., Rhizopus arrhizus, Mucor miehei, Phanerochaete chrysosporium, have been studied for As sorption. Keeping in view the potential threat of As(III) to environment and importance of fungi in bioremediation, this thesis research was designed. For this study, fungal isolates were obtained from contaminated soils collected from peri-urban areas of Multan and Gujranwala under untreated industrial and/municipal effluents irrigation. The fungal strains were also obtained from nonpolluted soil of Islamabad. Eighteen (18) prominent fungal isolates (5 from Multan, 6 from Gujranwala and 7 isolated from Islamabad) were tested for arsenic (III) tolerance by growing on Potato Dextrose Agar (PDA) medium amended with increasing As(III) concentrations (50 to 5600 mg kg-1). Fungal isolates tolerance was evaluated by measuring Tolerance Index (TI), Minimum Inhibitory Concentrations (MIC) and tolerance level. Out of 18 isolates, 12 were belonged to genus Aspergillus, 3 to Fusarium, 2 to Curvularea and one to Penicillium. Fusarium oxysporum and Aspergillus fumigatus appeared to be most tolerant. Fungal strains isolated from Gujranwala soil exhibited more As(III) tolerance than those from Multan and Islamabad. Maximum fungal growth was observed at temperature 30 to 35 oC, pH 6 to 7 over a period of 96-120 hrs. Most of the isolates (11 out of 18) showed exponential reduction in radial growth with increase in As concentration from 0 to 300 mgL-1. Afterwards, these isolates showed gradual reduction in growth and after 2000 mg L-1, no growth was observed in these strains. While four strains (two from Gujranwala - A. fumigatus and F. oxysporum; one from Multan - A. fumigatus and one from Islamabad - A. fumigatus) grew even up to As (III) concentration of 5600 mg L-1. The four isolates, G-2, G-5, M-4 and I-5, were observed most arsenic resistant and out of the four isolates, three,G-2, M-4 and I-5 were identified as Aspergillus fumigatus and one, G-5, was identified as Fusarium oxysporum. These four As tolerant isolates were selected for As removal capacity from aqueous solution and As sorption studies. Treated (with NaOH and FeCl3) and untreated arsenic tolerant fungal bio-mass of each strain was equilibrated with synthetic aqueous solutions of varying As(III) concentrations ranging from 0 to 1000 mg L-1 for a period of 240 minutes on a rotary shaker at 150 rpm at temperature of 28 + 2 oC. As(III) removal capacities were calculated using mass balance equation. FeCl3-treated G-2 (Aspergillus fumigatus) fungal biomass removed 3.2 mg As g-1 fungal biomass wheraeas NaOH-treated biomass removed 2.83 mg g-1 and untreated biomass removed 2.66 mg As g-1 fungal biomass. Maximum increase in As (III) removal due to FeCl3 treatment was 33.65 % over untreated whereas alkali (NaOH) treatment enhanced 22.27 % As(III) removal over untreated. As(III) removals by untreated, NaOH- and FeCl3-treated Fusarium oxysporum (G-5) biomass were up to 2.56 mg g-1, 3.02 mg g-1 and 3.39 mg g-1, respectively. FeCl3-treatment increased As(III) removal up to 28.16% over untreated, whereas increase due to alkali-treatment was low (up to 19.26%). As(III) removal capacity of untreated and treated wet biomass of M-4 (Aspergillus fumigatus), isolated from Multan also showed that FeCl3-treated biomass removed more As(III) than NaOH-treated and untreated biomass. The maximum As (III) removal with FeCl3- treated fungal (M-4) biomass was 3.27 mg g-1, followed by removal with NaOHtreated biomass (2.93 mg g-1) and untreated biomass (2.72 mg g-1). There was an increase in As(III) removal due to FeCl3-treatment up to 63.37% than untreated biomass. The increase in As(III) removal due to NaOH treatment was relatively less, i.e., 22.48 %. Arsenic (III) removal capacities of I-5 (Aspergillus fumigatus),obtained from non-contaminated soil of Islamabad, was also studied as a function of the initial As(III) solution concentration and like earlier isolates As(III) removal by biomass treated with NaOH and FeCl3 was higher than untreated biomass at higher concentrations (>300 mg L-1). The maximum As(III) removal was with FeCl3-treated biomass (3.20 mg g-1), while NaOH-treated removed 2.85 mg g-1 and untreated biomass removed 2.63 mg g-1. FeCl3-treatment increased up to 31.95% As(III) removal whereas alkali-treatment enhanced 27.91%. In general, a linear increase in As(III) removal up to the concentration of 300 mg L-1 was observed and then was gradual increase from 300 to 700 mg L-1 As(III) concentration and afterwards there was almost no increase. The results indicated that treated and untreated biomass of all the four selected fungal isolates removed significant amounts of As(III) from synthetic arsenic aqueous solutions. The treatment of biomass with NaOH and FeCl3 further enhanced the As(III) removal. The FeCl3-treated biomass removed more As from aqueous solution than that treated with NaOH. The results also indicate that fungal strains belonged to Aspergillus fumigatus,either isolated from heavy metals contaminated soils or non-polluted soil were capable to grow and remove As(III) at higher concentrations showing that the fungus specie is more important than site of isolation. Arsenic sorption parameters i.e. maximum sorption capacity and binding strength of the treated and untreated fungal biomasses were calculated using classical sorption models, Langmuir and Freundlich. High values of Langmuir regression coefficient (r2) (≥0.97) indicated its better fitness to adsorption data of than that of Freundlich model having regression coefficient values ≤0.90. The treatment of fungal biomass, either with NaOH or FeCl3, increased the maximum adsorption capacity of As (III) significantly over untreated fungal biomass; while the FeCl3 treatment increased As (III) sorption more than that of NaOH treatment. The maximum As (III) sorption capacity obtained by FeCl3-treated fungal biomass was 3.65 mg As (III) g-1 of wet fungal biomass followed by 3.55 mg As (III) g-1 by fungal biomass treated with NaOH and 3.37 mg As (III) g-1 of untreated fungal biomass. The Langmuir maximum sorption capacity of Fusarium oxysporum (G-5) was 3.85 mg g-1 biomass treated with FeCl3 and was 3.32 and 2.76 mg g-1 for NaOH treated and untreated biomasses, respectively. Relatively high maximum Langmuir sorption capacities were observed in case of Aspergillus fumigatus (M-4), i.e., 3.846 mg g -1 , 4.00 mg g-1, 3.953 mg g-1 for untreated, NaOH- and FeCl3-treated wet biomasses, respectively. The fungal strain isolated from non-contaminated soil, Aspergillus fumigatus (I-5), also showed equally good sorption capacity when treated with FeCl3 (4.149 mg g-1) and slightly less sorption was observed when treated with NaOH (3.521 mg g-1) but was better than untreated (3.125 mg g-1). The FeCl3 treatment of fungal biomass proved better and enhanced more As sorption than that of NaOH treatment. Results indicate that the tested arsenic tolerant fungal strains could remove significant amounts of arsenic from arsenic ammended media under laboratory conditions and the fungal strains may be used as an effective sorbent in arsenic removal technology from arsenic contaminated waters and soils." xml:lang="en_US
The COVID-19 outbreak has had a serious impact on almost all countries in the world, including Indonesia. In response to this case, various policies began to emerge. Starting from the implementation of work from home, social distancing and physical distancing, until the implementation of large-scale social restrictions (PSBB). Overseas investors are busy focusing their finances on the needs of their respective countries to fight the virus. Domestic investment (PMDN) is also predicted to experience a slowdown. The social distancing policy resulted in the community not being able to run the economic system well, especially in the Indonesian investment sector so that the perokoniman namely investment in Indonesia decreased and there were some delays in investment by other countries in Indonesia.
Expansive soils are rated as problematic soils because of their inherent potential to undergo large volume changes corresponding to changes in the moisture regime. They are considered potential natural hazard, which can cause extensive damage to structures if not adequately treated. When such soils absorb water they tend to expand and on the other hand, on drying they shrink and exhibit cracks. When such soils expand, they can exert enough uplift pressure on overlying structures, especially to lightly loaded structures such as single to double storeyed houses, pavements, floors and canal linings etc., causing severe damages in the form of uplifting and cracking of these structures. Reports on geotechnical investigations of various areas in Pakistan have revealed that considerable area of the country is covered with such soils and have caused severe damages to various types of structures. Identification of such soils at the investigation stage may help mitigating the detrimental effects of such soils. For preliminary identification of expansive soils by using empirical correlations between swelling parameters and index properties of the soils are very useful. Thus considering the problems associated with local expansive soils, there was a dire need to collect enough data of local soils and to determine swelling characteristics of such soils for the rating of their swell potential in order to develop specific mathematical models (based on index properties). Also, there is a common trend to develop zonation maps for the identification of such soils in different countries to enable better planning of infrastructure. Likewise, zonation maps for the local expansive soils were essentially required to facilitate the geotechnical engineers dealing with such soils. This research is mainly focused on the identification of local expansive soils and their characterization with respect to their swelling characteristics and mapping of such soils in different parts of the Punjab province of Pakistan. After collecting the data of basic classification tests from different agencies/organizations involved in geotechnical exploration in Pakistan, it has been established that the problem of swelling is mainly present in five districts of Punjab namely Dera Ghazi Khan, viii Chakwal, Sialkot, Gujranwala and Narowal. For detailed investigation, undisturbed and disturbed soil samples were retrieved from twenty eight different sites present in the potential swelling districts of Punjab. For geotechnical characterization of these soils, basic classification tests, X-ray diffraction analysis, expansion index tests, swell tests and compaction tests were performed.Expansion index (EI) test is considered to be an imperative classification test for the identification of the expansive soils. However, this test is quite time consuming and requires an elaborate testing arrangement. In this research, apparatus for performing the EI test was developed and based on extensive testing, an effort was made to correlate the EI parameter with plasticity index of the soil which can be determined through a simple Atterberg limit test. Through a series of EI tests on all samples including bentonite mixed samples (to have large variation in PI values), a linear relationship has been developed between plasticity index and expansion index parameter as given below. EI = 3.52 x PI----------------------------------------------------------------A-1 In order to explore the effects of various factors, which may affect the swelling properties of expansive soils such as initial moisture content, initial dry unit weight, plasticity index, surcharge pressure and mixing with non-swelling soil, a comprehensive laboratory testing programme was undertaken. Following are the salient findings of the laboratory investigations.· A series of swell tests were performed by varying remoulding initial moisture content and dry unit weight of the samples. It was revealed that both the swell potential (percent swell) and swell pressure are affected by changing initial moisture content of the samples remoulded on a specific initial dry unit weight. Swell potential decreased from 8.4% to 0.07% and swell pressure from 167 kPa to 5 kPa, when initial moisture content was increased from 0% to 20%. It implies that swelling problems can be mitigated by increasing moisture content. Moreover, swell potential increased from 0.07% to 8.4% and swell pressure from 5 kPa to 167 kPa when initial dry unit weight was increased from 14 kN/m3 to 18 kN/m3 ix showing that both swell potential and swell pressure values are more for the denser samples and less for the samples having low density.· Bentonite was added into the soils in increments from 0% to 100% (to have large variation in PI values) to investigate the effect of plasticity index. It has been observed that swell potential increased from 2.5% to 42.4% and swell pressure increased from 65.5 kPa to 850.6 kPa with the increase in plasticity index from 10% to 303%. · Swell tests on soil samples remoulded with different compaction energies revealed that when compaction energy was increased from 202 kJ/m3 to 2556 kJ/m3, swell potential increased from 0.4% to 8.8% and swell pressure increased from 10 kPa to 278 kPa. Moreover it has been observed that at a specific compaction energy level, for compaction moisture content dry of optimum, the swell potential tended to be significant and as the compaction moisture was more than OMC, the swell potential decreased. This finding implies that if the field compaction is performed slightly on wet of optimum, the swelling potential of the compacted soil can be effectively mitigated in field practice. · Series of swell tests with varying surcharge pressure on soil samples during saturation showed that when surcharge pressure was increased from 6.9 kPa to 27.6 kPa, both swell potential and swell pressure decreased from 9.4% to 0.2% and from 162 kPa to 8 kPa, respectively. This finding is very useful in controlling swelling of soils in the field. By increasing the vertical surcharge pressure on such soils in the form of foundation bearing pressure (within allowable bearing capacity of the soil), problems associated with swelling can be mitigated. · In order to investigate the effect of blending with non-swelling soil in swelling clays, a series of swell tests was performed by mixing locally available sand into the expansive soil samples. It was revealed that swell potential decreased from 9.4% to 0.4% and swell pressure decreased from 162 kPa to 7 kPa when the sand was added from 0% to 25%. Addition of about 20% locally available sand transformed high swelling soil into low x swelling soil. This finding may also be very useful in controlling the problems associated with swelling of expansive soils by mixing locally available sandy soil in proportion of 20~25%. By using the results of all swell tests performed on the samples collected from potential swelling districts of Punjab including bentonite mixed samples, a linear relationship between swell pressure and swell potential has been developed as given below. Swell Pressure (kPa) = 20.4 x Swell Potential ------------------------ A-2 Through a comprehensive data analysis of the swell tests investigating the various factors, it was revealed that the swelling parameters (swell potential and swell pressure) of the expansive soils are mainly affected by varying the plasticity index, field moisture content and field dry unit weight of the soils. In this connection, multiple linear regression analysis was performed on the investigated swell data and correlations between swelling parameters and the three affecting parameters, plasticity index, initial moisture content and initial dry unit weight, have been developed as given below. Sp =0.111 PI + 1.12 γd –0.208 w – 14.5 -------------------------------A-3 Ps = 2.22 PI + 28.2 γd – 1.87 w – 417 -------------------------------- A-4 whereSp = Swell potential (%), Ps = Swelling pressure (kPa), PI = Plasticity index (%) γd =Initial dry unit weight (kN/m3) and w =Initial moisture content (%) The above mentioned correlations given by equations A-3 and A-4 were duly validated by using the data of swell tests performed on all soil samples collected from various sites. It is to mention here that this data was not included in the development of the correlations. Comparisons of experimentally measured and predicted swelling parameters by equations A-3 and A-4 show that the proposed correlations can predict the swelling parameters of the soils within an accuracy of +10% which may be considered a reasonable prediction for preliminary purposes. Finally, zonation maps have been developed for the identification of expansive soils in Punjab province area based on plasticity index, liquid limit and depth of expansive soil using GIS (Geographic Information System) software with the help global coordinates of the sites investigated. Moreover, using the proposed models by equations A-3 and A-4, zonation maps for predicting swell potential and swell pressure have also been developed using the modified Proctor compaction test parameters (γdmax & OMC) and the plasticity index data of the investigated areas. As an outcome of this research, it can be said that the proposed mathematical models between swelling parameters and the basic properties of the soils will be a source of quick prediction of swelling characteristics of the expansive soils present in the Punjab province of Pakistan. Moreover zonation maps developed using GIS software based on Atterberg limits data and the proposed mathematical models (using the PI values and the field compaction parameters) can be used effectively to predict the swell potential and swell pressure at various locations. The findings of this research may provide a tool for quick identification and prediction of swelling parameters of expansive soils present in the Punjab region which will be quite useful during preliminary design stages of any civil engineering project." xml:lang="en_US