Bioaccumulation of arsenic in aquatic plants and animals near a municipal landfill

This study was conducted to assess the water quality and arsenic (As) concentrations in water, sediment, aquatic plants and animals near a municipal landfill. The As concentration in the samples was analysed using inductively coupled plasma optical emission spectrometry. Thirty-six aquatic plants of four species were collected. The highest As concentration was found in Limnocharis flava (0.78 ± 0.31 mg/kg). The aquatic animals included 31 fish of four species and 27 freshwater snails of three species. The highest As concentrations in the fish and freshwater snails were found in Oreochromis niloticus (0.16 ± 0.16 mg/kg) and Filopaludina sumatrensis (0.18 ± 0.06 mg/kg), respectively. The highest bioaccumulation factor of As in the aquatic plants, fish and freshwater snails were found in L. flava (131.30 ± 15.35), O. niloticus (228.21 ± 26.99) and F. sumatrensis (33.04 ± 10.58), respectively. Since the accumulation of As was higher in the sediment than in the water, aquatic plants and animals took up As directly from the environment, resulting in As accumulation in the aquatic food web.     

Microbial leaching of El-Sella mineralisation by Aspergillus clavatus- a fact of fungal–uranium interface

ABSTRACT

This study evaluates the bioleaching of uranium from El-Sella mineralisation by Aspergillus clavatus. A. clavatus was generally found to give the maximum bioleaching efficiency of uranium under two-step bioleaching process when a total concentration of 3% (w/v) El-Sella mineralisation was applied. Microscopic examination revealed that bioleaching negatively affected fungal vesicles, and resulted in the formation of a swollen pellet structure in the mycelium. Uranium precipitated as uranium calcium phosphate mineral (Autunite) crystals on the surface of hyphae. Finally, the purity of uranium assayed was 73.19% in sodium diuranate. In conclusion, the optimum conditions for bioleaching of uranium from El-Sella mineralisation using A. clavatus are 9 days of incubation, 30^°C and agitation speed of 175 rpm. A. clavatus represents an excellent candidate for uranium bioleaching from its ore.     

New insights concerning the occurrence of fungi in water sources and their potential pathogenicity

Fungi are known to occur ubiquitously in the environment. In the past years, the occurrence of filamentous fungi in the aquatic environment has been a subject of growing interest. This study describes the occurrence of various fungal genera in different drinking water sources being Penicillium and Trichoderma the most representative ones (30% and 17%, respectively). Also, 24 fungal species that have not been previously described in the aquatic environment are reported in this study, being once again the major species from the Penicillium genera. This study therefore contributes to the knowledge on the richness of fungi diversity in water. 68% of the described species were found to be able to grow at 30 °C but only Aspergillus fumigatus, Aspergillus viridinutans and Cunninghamella bertholletiae were able to grow at the higher temperature tested (42 °C). 66% of the species that were able to grow at 30 °C have spore sizes below 5 μm which enables them to cause breathing infections. These were therefore identified as potential pathogenic species.     

Human health risks of untreated groundwater third pipe supplies for non-potable domestic applications

A quantitative microbial risk assessment (QMRA) was undertaken to determine the potential human health risks associated with use of untreated groundwater from a superficial aquifer in a new residential urban development. In situ pathogen survival experiments determined the attenuation rates of selected pathogens. Cryptosporidium oocysts, Giardia cysts, E. coli, Campylobacter jejuni, and MS2 bacteriophage had 1 log₁₀ (90%) reduction times (T₉₀) ranging from 2 to 42 days. Adenovirus displayed distinctly non-linear broken stick decay rates with an initial T₉₀ of 5 days to day 14, after which the T₉₀ declined to ～100 days. The QMRA suggested that aquifer attachment was the dominant form of pathogen removal followed by natural attenuation. The QMRA results showed that under the exposure scenarios tested the mean human health risks were all acceptable with calculated Disability Adjusted Life Years (DALYs < 1 × 10^? 6/person/year).     

Disappearance of aromatic hydrocarbons and organic sulfur compounds from fish flesh reared in crude oil suspension

Eels (Anguilla Japonica Temminck et Schlegel) were reared in sea water containing a crude oil suspension (50 ppm for 10 days for aromatic hydrocarbons, 2500 ppm for 3 days for organic sulfur compounds), then transferred to clean sea water. The disappearance of aromatic hydrocarbons and organic sulfur compounds from eel flesh was examined. The concentration ratio (concentration of eel flesh/concentration of water) of benzene, toluene, m- or p-xylene and o-xylene at 10 days was 3.5, 13.2, 23.6 and 21.4 respectively.Benzene, toluene, m- or p-xylene and o-xylene disappeared after the transfer to clean sea water, and the half-life period was 0.5, 1.4, 2.6 and 2.0 days respectively in the first phase which lasted 0–5 days.Organic sulfur compounds in cel flesh decreased as the time spent in clean sea water increased, but were still present after 30 days.The results suggest that aromatic hydrocarbons and organic sulfur compounds could serve as markers of oil pollution in fish.     

Emission of pollutants from wood waste incineration at sawmills in Abeokuta metropolis,Nigeria

This paper reports an assessment of the effects of wood waste burning on air quality and the perceived human health in an urban setting. The concentrations of particulates and selected gases were monitored within the vicinity of sawmills in Abeokuta metropolis. The levels of CO, CO₂, SO₂, NO_x, NO₂, H₂S, CH₄ and particulates at distances from sawmill dumps were measured using portable samplers. Additionally, information on sawmill operations and health problems encountered by the exposed population were collected from a community survey. From the data analyses, between 60 and 100% of wood waste generated by sawmills were burned openly, leading to pollutants emission. The mean concentrations of PM_0.3–0.5 (32 523–40 284 μg/m³), NO₂ (1.0 ppm), SO₂ (3.3 ppm), CO (759 ppm) and CO₂ (4.9%) were higher than the permissible limits at 0–15 m from the dump sites. Almost all sampled parameters showed positive association (R = 0.90–0.98; p < 0.05) at sample sites. Moreover, distance of sites to the dumps explained 51–93% of the variation in parameters levels. Both respiratory and dermal diseases were frequently experienced by the exposed population. Strict land-use zoning, pollution abatement measures, environmental quality monitoring and waste-to-energy interventions are urgently required in the study area.     

Biodegradation of 2-methylisoborneol by single bacterium in culture media and river water environment

2-Methylisoborneol (2-MIB) is a typical odorant in water sources. It is difficult for conventional water treatment to remove it. In this study, three strains capable of removing 2-MIB were isolated from activated carbon of sand filter. They were identified to be Shinella zoogloeoides, Bacillus idriensis and Chitinophagaceae bacterium based on 16S rRNA gene sequence analysis. The biodegradation of 2-MIB was improved with the presence of external carbon (glycerol, glucose, etc.). In the period of 20 days, Bacillus idriensis can remove 2 mg L^?1 2-MIB to 368.2 and 315.4 μg L^?1 in mineral salts medium without and with glycerol. Chitinophagaceae bacterium can remove it to 265.6 and 185.4 μg L^?1 without and with glucose. The enzymatic activity of B. Idriensis was lower when external carbon coexisted with 2-MIB. This indicated that a carbon source can inhibit the use of 2-MIB, but it can provide rich nutrients for the growth of bacteria.     

Response of Aspergillus flavus,Aspergillus niger and Penicillium citrinum to oxidative stress induced by Fenton’s reagent

The presence of fungi in water systems represents a threat to human health. Hydrogen peroxide is known for its disinfecting properties and easy decomposition to water and oxygen. Its activity can be enhanced by the addition of iron as a catalyst, a reagent known as Fenton?s reagent. In the present study, different Fenton concentrations were investigated on the spores of Aspergillus flavus, Aspergillus niger and Penicillium citrinum at different time intervals. The results indicate that complete inactivation of spores was noticed after 60 min of exposure to both 2 and 3% H₂O₂ catalyzed by 0.025 g Fe²⁺/100 ml for A. niger, and 3% H₂O₂ catalysed by 0.075 g Fe²⁺/100 ml for P. citrinum. The activity of two antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), was determined in mycelial mat harvested after 7 days. Their activities were either highly increased or reached their minimum values prior to inactivation of spores.     

Sphagnum mosses on the mires of the Altai-Sayan Mountains region

Abstract

Sphagnum mosses are a characteristic component of plant communities in the mountain mires of the Altai-Sayan region. The genus Sphagnum L. ranks first in the species diversity and includes 32 species, accounting for 57.1% of the species diversity of sphagnum mosses of Russia and 62.8% of the species diversity of sphagnum mosses of the Asian part of Russia. Twenty-five species of sphagnum moss are revealed in the mires of the Western Sayan and Altai, listed in this paper; 28 species occur on the Kuznetsky Alatau mires. Rare species are Sphagnum aongstroemii, S. auriculatum, S. contortum, S. platyphyllum, S. pulchrum, S. subfulvum, S. tenellum.     

Spatial variation of boron in groundwater in South Iraq

The research investigated boron variability in space and time, using 450 groundwater samples from 75 representative wells in the Safwan–Zubair area of Basra district, South Iraq, collected monthly from January to June 2000, with also 75 soil samples from selected farms in the same area. Minimum and maximum values of boron concentrations range from 1.49 to 9.49 ppm respectively. Boron concentration in groundwater spatially occurs in 90% in frequency between 2 and 4 ppm, while 5% below 2 ppm and 5% is more than 4.0 ppm to more than 9.0 ppm, where the soluble boron concentrations of soil samples range from 0.60 to 7.02 ppm. Soil boron concentration spatially occurs 95% below 6.0 ppm and 5% more than 6.0 ppm. The results show that the variability of boron concentration in groundwater and in soil mostly depends upon irrigation water, cyclic differences of the sediment facies horizontally and vertically, and also the period of precipitation (rainfall); i.e. wetting and drying processes. The results indicate that there will always be available boron in the soil at the end of the irrigation period (May–June) ready to be leached again by the first percolated rainfall (effective rainfall) to join the groundwater at higher concentration. The results show that the variability of boron concentration in groundwater and in soil mostly depends upon irrigation water, cyclic differences of the sediment facies horizontally and vertically, and also the period of precipitation (rainfall); i.e. wetting and drying processes. The results indicate that there will always be available boron in the soil at the end of the irrigation period (May–June) ready to be leached again by the first percolated rainfall (effective rainfall) to join the groundwater at higher concentration.     

Effect of heating the catalytic converter on emission characteristic of gasoline automotive vehicles

Gasoline engines have been widely used as engineering machinery, automobile and shipping power equipment due to their excellent drivability and economy. At the same time, gasoline engines are major contributors to various types of air pollutants such as carbon monoxide (CO), oxides of nitrogen (NO_x), and other harmful compounds. With the increasing concern of environment and more stringent government regulation on exhaust emissions, the reduction in engine emissions such as particulate matter and NO_x is a major research objective in engine development. In this article the effect of heating the catalytic converter on emission characteristic of automotive vehicles in its starting phase of combustion has been studied. In this work, the emission characteristic of hydrocarbons has been improved from 800 to 15 ppm, CO from 4 to 0.07 (V/V%) and NO_x from 1200 to 115 ppm.     

Study of bio-aerosols in a prominent temple in Mumbai City,India

Numerous health complaints occur with respect to indoor air quality and scanty information is available on the air flora, particularly with respect to bio-aerosols in India. This paper reports a study which examined air quality in a prominent temple in the city of Mumbai. It was found that the indoor microbial load was significantly higher probably because appropriate ventilation systems were lacking. In the festive month of September, the highest bacterial counts (13.98 × 10⁴ CFU/m³) and fungal counts (9.22 × 10⁴ CFU/m³) were observed. Pseudomonas spp. and Aspergillus spp. were found to be predominant in the air microflora sampled. Correlation analysis with meteorological factors such as temperature, relative humidity and wind speed showed that these were non-significant. The study indicated that poor ventilation, number of occupants and their activities in a given area are largely responsible for the variation in microbial loads observed. The data generated underline the question of monitoring crowded areas including places of religious importance. Some remedial measures are suggested.     

Pre‐contamination of new gypsum wallboard with potentially harmful fungal species

Gypsum wallboard is a popular building material, but is also very frequently overgrown by Stachybotrys chartarum after severe and/or undetected water damage. The purpose of this study was to determine whether Stachybotrys and other fungi frequently isolated from wet gypsum wallboard are already present in the panels directly from the factory. Surface‐disinfected gypsum disks were wetted with sterile water, sealed, and incubated for 70 days. The results showed that Neosartorya hiratsukae (≡ Aspergillus hiratsukae) was the most dominant fungus on the gypsum wallboard followed by Chaetomium globosum and Stachybotrys chartarum. Our results suggest that these three fungal species are already embedded in the materials, presumably in the paper/carton layer surrounding the gypsum core, before the panels reach the retailers/building site.     

Fungal and bacterial growth in floor dust at elevated relative humidity levels

Under sustained, elevated building moisture conditions, bacterial and fungal growth occurs. The goal of this study was to characterize microbial growth in floor dust at variable equilibrium relative humidity (ERH) levels. Floor dust from one home was embedded in coupons cut from a worn medium‐pile nylon carpet and incubated at 50%, 80%, 85%, 90%, 95%, and 100% ERH levels. Quantitative PCR and DNA sequencing of ribosomal DNA for bacteria and fungi were used to quantify growth and community shifts. Over a 1‐wk period, fungal growth occurred above 80% ERH. Growth rates at 85% and 100% ERH were 1.1 × 10⁴ and 1.5 × 10⁵ spore equivalents d^?1 mg dust^?1, respectively. Bacterial growth occurred only at 100% ERH after 1 wk (9.0 × 10⁴ genomes d^?1 mg dust^?1). Growth resulted in significant changes in fungal (P<.00001) and bacterial community structure (P<.00001) at varying ERH levels. Comparisons between fungal taxa incubated at different ERH levels revealed more than 100 fungal and bacterial species that were attributable to elevated ERH. Resuspension modeling indicated that more than 50% of airborne microbes could originate from the resuspension of fungi grown at ERH levels of 85% and above.     

Adapting household water use in rural Zimbabwe

The study investigated how rural communities in semi-arid areas (1) adapt household water management to effects of climate variability and (2) how such adaptation influences household water usage and its quality. A semi-structured questionnaire was administered to 180 households between July and December 2014 to obtain demographic data on water supply and use. Microbiological quality of source and stored drinking water was determined using a Potatest field kit. In times of water scarcity, households exploited distant (>1 km) sources and stored large quantities (>60 L) of water up to >4 days. Water was re-contaminated by faecal coliforms during storage. Distance to a water source, sharing a source, type of lifting device, type of source and collector of water significantly influenced water supply across villages (p < 0.05). Villagers were more likely to draw less water at greater distances. Point-of-use water treatment and improved hygiene behaviour are recommended.     

Swell–compression characteristics of a fiber–reinforced expansive soil

This study presents results of an experimental program with respect to fiber's capacity of mitigating the swelling behavior of an expansive soil. Two types of tape–shaped fibers, i.e. fiber A (width f_w = 2.5 mm) and fiber B (f_w = 7 mm), were used as the reinforcements. The fibers were included at three contents, i.e. f_c = 0.5%, 1% and 1.5%, each having two lengths or aspect ratios (f_AR = 15/2.5 and 30/2.5 for fiber A, and f_AR = 15/7 and 30/7 for fiber B). For a given fiber type (constant f_w), improvement in swelling potential/pressure was observed to be a direct function of f_c and f_l (fiber length) or f_AR, with the former taking on a more pronounced role. In addition, for a given f_c and f_l, the wider fiber (lower f_AR) was more efficient in restricting swelling. The compression characteristics were cross–checked with the swelling properties to arrive the optimum stabilization scenarios. For both fiber types, f_c = 0.5% suggested an optimal case. However, where compressional deformations are not a primary concern, higher inclusions up to 1% could also be an acceptable choice.     

Characterization of Emissions from Liquid Fuel and Propane Open Burns

The effect of accidental fires are simulated to understand the response of items such as vehicles, fuel tanks, and military ordnance and to remediate the effects through re-design of the items or changes in operational procedures. The comparative combustion emissions of using jet propellant (JP-5) liquid fuel pools or a propane manifold grid to simulate the effects of accidental fires was investigated. A helium-filled tethered aerostat was used to maneuver an instrument package into the open fire plumes to measure CO, CO₂, fine particulate matter (PM_2.5), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and elemental/organic/total carbon (EC/OC/TC). The results showed that all emissions except CO₂ were significantly higher from JP-5 burns than from propane. The major portion of the PM mass from fires of both fuels was less than 1 µm in diameter and differed in carbon content. The PM_2.5 emission factor from JP-5 burns (129 ± 23 g/kg Fuel_c) was approximately 150 times higher than the PM_2.5 emission factor from propane burns (0.89 ± 0.21 g/kg Fuel_c). The PAH emissions as well as some VOCs were more than one hundred times higher for the JP-5 burns than the propane burns. Using the propane test method to study flammability responses, the environmental impact of PM_2.5, PAHs, and VOCs would be reduced by 2300, 700, and 100 times per test, respectively.     

Biological activities of endozoic fungi isolated from Biomphalaria alexandrina snails maintained in different environmental conditions

This work aims at studying Biomphalaria alexandrina snails as a source of bioactive compounds. Adult snails were maintained in plastic, mud and cement matrices. Three groups were prepared; under normal laboratory conditions, in slightly low pH conditions, and in high temperature (30°C) conditions. Nine fungal species were isolated from soft tissues of snails. Ethyl acetate and acetone extracts were prepared from each fungal species, and their biological activities were investigated. Paecilomyces variotii extracts were the most effective as antimicrobial agents, while acetone extract of Trichoderma harzianum showed high antioxidant activity. Acetone extracts of Penicillium islandicum and Aspergillus niger were highly active against hepatocellular carcinoma (HepG2) cell lines. Gas chromatography/mass spectrometry analysis of the five effective extracts showed the presence of various compounds. B. alexandrina snails may be regarded as a newly discovered source of beneficial compounds through the metabolites produced by their endozoic fungal strains.     

Assessment of phosphogypsum use in a nursery for plant propagation

Phosphogypsum (PG) was used as substrate for the multiplication of eight ornamental species; six by cuttings and two by sowing. The results obtained showed a high rooting or percent germination for the six plants: Ficus benjamina, Pelargonium × Hortorum, Washingtonia filifera, Eucalyptus camaldulensis, Hibiscus rosa sinensis and Acalypha wilkesiana. For a percentage of 50% PG, only F. benjamina, H. rosa sinensis and W. filifera showed high percentage rooting. Plant vigour (height and biomass) depends on both species and treatment. Two species showed high sensitivity to PG during the propagation by cuttings, Nerium oleander and Myoporum laetum. We observed high variation in substrate characteristics; with 50% PG, pH was increased from 2.84 to 6.22, and electrical conductivity (EC) and gypsum concentration were reduced from 15.56 to 4.23 mS/cm from 36.23 to 11.82%, respectively. The results showed the possibility of using PG in nurseries for the multiplication and fertilization of several forest and ornamental plant species by cuttings and sowing.     

Isolation,characterisation and efficacy of the bacterial strain Lysinibacillus sphaericus YMM in biodegradation of malathion insecticide in liquid media

A new isolate of bacterium Lysinibacillus sphaericus YMM capable of degrading malathion insecticide in liquid media was isolated and characterised. Biodegradation factors were investigated using Plackett–Burman factorial design, and the rest of the insecticide was monitored by high-performance liquid chromatography analysis. The near optimum conditions for degradation of 200 mg malathion/L were 30 mL medium, 2% of L. sphaericus suspension (0.70 OD_600nm), pH 5,10 g/L glucose, 1.0 g/L NaCl, 0.3 g/L MgSO₄, 1.0 g/L NH₄Cl and incubation for 24 h without yeast extract and peptone or beef extract. In addition, the significant variables including the medium volume, inoculum and incubation time were further optimised using Box–Behnken response surface design. These conditions were found to be 30.10% medium and inoculum of 0.706 (OD_600nm) for 23.636 h of incubation to achieve 98.974% degradation. Therefore, L. sphaericus YMM showed a potential degradation of malathion. Further studies should be conducted to understand the mechanism of biodegradation in liquid media.