Cytotoxic effect of sodium arsenite on Nile tilapia (Oreochromis niloticus) in vivo

This study showed the relevance of using chromosomal aberration (CA) as potential indicators of sodium arsenite (SA; NaAsO₂) cytotoxicity. The study investigated cytotoxic potential of SA in Oreochromis niloticus using CA assessment. The fish were exposed to four different concentrations of SA (5, 10, 20 and 40 mg/L) for 24 hours in comparison to a control group. The As concentrations in the samples were analysed by inductively coupled plasma atomic emission spectrometry. The differences in As concentrations in the water and O. niloticus samples between the control and experimental groups were significant (p<0.05), whereas the within experimental group differences were not significant. The cytotoxic assessment of SA in O. niloticus revealed five types of CAs, including single chromatid gaps (SCG), single chromatid break (SCB), centric gap (CG), fragmentation (F) and deletion (D). The most common CA in the O. niloticus samples was SCG. A total of 2.33, 10.67, 18.67, 18.00 and 23.67% of the cells in the control and experimental groups exhibited CAs. The numbers of CAs and cells with CAs from the control and experimental groups of fish were significantly different (p<0.05); additionally, the fish exposed to 5 and 40 mg/L showed significant within experimental group differences (p<0.05).     

Cytotoxic assessment of flying barb fish (Esomus metallicus) from a gold mine area with heavy metal contamination

This study aimed to investigate contamination by heavy metals including arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), and manganese (Mn) and to conduct a cytotoxic assessment of Esomus metallicus from a gold mine area compared with that from the non-affected area. The E. metallicus samples were collected downstream of a gold mine area. The heavy metal concentrations were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The average amounts of As, Cd, Cr, Pb and Mn in water and E. metallicus samples from the gold mine area were 0.368 ± 0.009, 0.008 ± 0.006, 0.009 ± 0.001, 0.006 ± 0.002, 1.438 ± 0.058 mg/L, 0.65 ± 0.25, 0.03 ± 0.03, 2.12 ± 0.05, 0.25 ± 0.07 and 18.28 ± 6.82 mg/kg, respectively. The difference of As, Cr and Mn concentrations in E. metallicus samples between gold mine and non-affected areas was statistically significant (p < 0.05) except for Cd and Pb. The diploid chromosome number of E. metallicus from both areas was 2n = 50. There are six types of chromosomal aberrations including centric fragmentation (CF), centric gap (CG), single chromatid gap (SCG), fragmentation (F), deletion (D) and polyploidy (P). The most common chromosomal aberration type in the samples from the gold mine area was CG, and the difference in chromosomal aberration and the number of cells with chromosomal aberrations in E. metallicus between the study areas was statistically significant (p < 0.05). The percentages of chromosomal aberrations in the E. metallicus samples from gold mine and non-affected areas were 14.66 and 3.00, respectively.     

Analysis of chromosome abnormalities in the Asian swamp eel (Monopterus albus) affected by arsenic contamination near a gold mine area

ABSTRACT

The paper reports a study of chromosome abnormalities (CA/s) in the Monopterus albus near a gold mine area compared to a non-affected area. The arsenic (As) concentrations were determined in the water, sediment and M. albus muscles. The average concentrations of As in the water and sediment samples near the gold mine were higher than allowable by Thailand’s water quality standards. The average concentrations of As in the M. albus samples were lower than the standards. The diploid chromosome number of M. albus in both areas was 2n = 24. The percentage of CA of M. albus in the gold mine area was higher than in the non-affected area. Seven types of CA were single chromatid gap (SCG), fragmentation (F), sister chromatid gap, single chromatid breaks, deletion, sister chromatid fragmentation and centric fusion. In the affected area, the most common CAs in the samples were SCG and F. The specific CA in M. albus samples was SCG on chromosome pair 1. It can be concluded that As contamination caused structural CA, but did not affect the diploid chromosome number in the Asian swamp eel from the gold mine area. The accumulation of As in M. albus has potential effects on human health in consumers of M. albus from this contaminated area.     

Abnormal chromosome assessment of snakehead fish (Channa striata) affected by heavy metals from a reservoir near an industrial factory

This study aimed to investigate nine heavy metal concentrations (As, Cd, Cr, Pb, Cu, Fe, Zn, Mn and Ni) in water, sediment and snakehead fish (Channa striata) and to identify abnormal chromosomes in C. striata from a reservoir near an industrial factory and a reference area. Heavy metal concentrations were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The metal concentrations in the water, sediment and C. striata samples did not exceed the standard limit of Thailand, except for Cr concentrations, which exceeded water quality standards. The concentrations of Cd, Fe, Mn and Ni in C. striata samples between the reservoir and the reference area were significantly different (p < 0.05). The diploid chromosome number of C. striata from both areas was (2n = 42). Eight types of abnormal chromosomes were identified and classified as a single-chromatid gap, a single-chromatid break, centric fragmentation, a centric gap (CG), fragmentation, deletion, single-chromatid decomposition and iso-arm fragmentation. The most frequent abnormal chromosome in the samples was CG. The percentages of abnormal chromosomes in the C. striata samples from the reservoir near the industrial factory and the reference area were significantly different (p < 0.05) at 8.44 and 1.20, respectively.     

Genotoxicity of recycling electronic waste in Idhna,Hebron District,Palestine

Most Electronic waste (e-waste) ends up in landfills while some is recycled. A major site for e-waste recycling in Palestine is the village of Idhna in the Hebron District and most of this waste originates from Israel. The objective of this study was to evaluate the effects of e-waste on human DNA damage and chromosome breaks. The test sample was 46 non-smoker individuals with direct exposure to e-waste, either employed in the workshops or resident in Idhna. Genotoxicity data were compared with a control sample of sixteen unexposed individuals from Bethlehem and Al-Aizariya (Bethany). DNA damage was evaluated using the Comet assay while chromosome aberrations were tested by using conventional cytogenetic techniques. We noted an average of 4.83 aberration/cell/subject in test samples while in controls the average was 0.75. Chromosome aberration frequency was statistically different between exposed and control samples for total aberrations, for chromatid and chromosome breaks, and for formation of rings but not for dicenterics and tetraploidy. The Comet assay likewise showed that there was significant difference between exposed and control samples for DNA damage (p < 0.05). We therefore recommend measures to mitigate the health impact of e-waste recycling.     

Mercury levels in Oryza sativa cultivated in Philippine small-scale mining villages

Soil physico-chemical parameters and total mercury concentrations were measured in soil and rice plant samples collected over a cropping period grown in areas near mine tailings ponds in two Philippine small-scale mining (SSM) communities. Step-wise regression analysis relating environmental parameters to Hg uptake showed that pH has a highly significant effect on Hg content in the samples (p < 0.001) while temperature, contrary to previous studies, had no significant effect. The mean total Hg concentrations appeared to be significantly lower in rice plant parts sampled in control sites than in the contaminated sites in both SSM communities: 0.020 and 2.832 mg/kg, respectively in Aroroy, Masbate and 0.004 and 0.016 mg/kg, respectively in Fidelisan, Sagada. Harvested rice grains from the Masbate sampling sites further revealed total Hg concentration at 0.1331 mg/kg, exceeding the maximum permissible limit of 0.02 mg/kg Hg contamination. The study shows that Hg use in SSM activities and the cumulative effects of prolonged exposure to the metal through regular consumption of the village-cultivated rice may put the local residents at risk of health problems related to mercury.     

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.     

Potential of citric acid to alter pH and metal uptake in reeds in acid mine drainage solutions

Phragmites australis (common reed) is often used to treat acid mine drainage (AMD) sites contaminated with high concentrations of heavy metals and low pH. This study investigated the effects of different levels (low 0.34 g/L, middle 17.86 g/L and high 33.62 g/L) of the biodegradable chelator citric acid (CA) on pH change, metal (i.e. Fe, Al and Mn) accumulation and translocation in reeds cultured in aqueous AMD contaminated media for 4 and 12 weeks. The results indicated that CA inhibited further deceases in AMD pH as well as increased Fe and Mn accumulation in both belowground and above ground tissues of reeds. As expected, increasing CA dosage and treatment time increased metal accumulation in plants. By 12 weeks, 0.18 ± 0.01 mg Mn/g, 56.78 ± 7.63 mg Fe/g and 0.60 ± 0.01 mg Al/g were accumulated in roots; while 0.06 ± 0.01 mg Mn/g; 6.38 ± 0.06 mg Fe/g; and 0.19 ± 0.01 mg Al/g were sequestered in stems of reeds treated with 33.62 g/L CA. Further research is needed to study the application of CA to enhance the phytoremediation efficiency of AMD contaminated field.     

Assessment of heavy metals contamination and its effects on oyster (Saccostrea cucullata) biometry parameters in the Asaluyeh port coasts,Persian Gulf,Iran

The current study examines biometric parameters and concentration of some heavy metals in soft tissues of Saccostrea cucullata in the Asaluyeh coast, Persian Gulf, Iran. The metals concentration in the soft tissue of the Saccostrea cucullata ranged as: Zn: 765–3411 mg kg^?1, Cu: 120.3–580.6 mg kg^?1, Cd: 0.13–3.5 mg kg^?1, As: 0.39–3.3 mg kg^?1, Pb: 0.05–1.64 mg kg^?1, Ni: 0.02–0.44 mg kg^?1, V: 0.06–0.32 mg kg^?1, Cr: 0.02–0.16 mg kg^?1 and Hg: 0.002–0.068 mg kg^?1. The results showed that the concentration of total heavy metals in oysters of the control station (CA) is usually lower. The results also indicated lack of correlation between oyster biometric parameters and bioaccumulated heavy metals, except between Cu and longitudinal diameter (R = 0.77). The concentration of heavy metals is higher than limits recommended by the World Health Organization, except for Cd and Pb.     

Effect of cadmium, lead and arsenic on the oviposition, hatching and embryonic survival of Biomphalaria glabrata

Biomphalaria glabrata is a widespread freshwater gastropod mollusc. The easy aquaculture of these organisms allow its use as an accessible tool for contamination bioassays. B. glabrata showed marked metabolic responses when exposed to cadmium, lead and arsenic. Those responses could also affect the reproduction of the snails. Taking into account this hypothesis, B. glabrata were exposed for 96 h (acute laboratory bioassays) to different concentrations of cadmium (0.1, 0.05 and 0 mg/L), lead (0.5, 0.1, 0.05 and 0 mg/L) and arsenic (0.5, 0.1, 0.05 and 0 mg/L). Snails were removed from the aquaria while eggs were left in the same contaminant concentrations. The effect of the assayed toxicants on snail reproduction was registered as the alterations of the total number of laid eggs (TNLE), hatching time and embryonic survival.At 0.10 mg/L cadmium significantly decreased the TNLE (p < 0.05) and no embryos survived. The lowest assayed level (0.05 mg/L) of cadmium, delayed the hatching time twice when it was compared with the control group (p < 0.01).Lead decreased the TNLE at 0.5 mg/L level (p < 0.01). The other assayed doses (0.05 and 0.10 mg/L) also decreased embryonic survival significantly (p < 0.05 and p < 0.01 respectively) and extended twice the time to hatching (p < 0.01). The 0.50 mg/L level killed all embryos.Arsenic at all studied concentrations decreased the TNLE (p < 0.05) while the hatching time was increased by 50%. Embryo survival only decreased at the highest level (0.5 mg/L) of arsenic assayed.In summary, the acute exposure (96 h) to cadmium lead and arsenic, altered the reproduction of B. glabrata, modifying the TNLE, hatching time and embryonic survival.     

Genotoxic effects of Israeli industrial pollutants on residents of Bruqeen village (Salfit district,Palestine)

Many industrial byproducts are genotoxic agents that induce cytogenetic changes and DNA damage. Bruqeen, a Palestinian village in Salfit district in the northern West bank, is subject to industrial waste products coming from Barqan Israeli industrial settlement. We evaluated the extent of chromosomal breaks (Csb) and DNA damage induced to human cells using whole blood samples from both test and control sites. Csb were assessed by routine cytogenetic methods and DNA damage was assessed via the Comet assay which is also called single cell gel electrophoresis. Cytogenetic analysis for Bruqeen residents’ sample (n?=?30) showed 133 Premature centromere separation (PCS), 43 Csb, 40 chromatid breaks (Ctb) and 26 dicentrics. In total, the findings showed an average of 4.08% chromosomal aberrations (CA) and 3.81% cells with CA. The results of controls (from Bethlehem area n?=?8) showed 21 PCS, 2 Csb, 5 Ctb and 2 dicentric, and in total the average showed 1.97 CA and 1.91% cells with CA. Statistical analysis showed that there were no significant differences between exposed and control subjects for PCS, Ctb and Dicentric (p-value?>?0.05), but there was a statistically significant difference for CA frequency for cells that have CA and Csb (p-value?p-value?相似文献   

Arsenic uptake potential of water lettuce (Pistia Stratiotes L.)

Arsenate uptake by aquatic plant water lettuce (Pistia stratiotes L.) was studied in the laboratory condition to investigate a low cost natural aquatic treatment system for pollutant removal. The plants were harvested from a local pollution‐free pond in young condition and hydroponically cultured in the laboratory. Bio‐accumulation was noticed to be both concentration and duration dependent. The results show that the plant could effectively absorb arsenic between a range of 0.25 to 5.0 mg/l to the extent of 82.0 to 22.8% for a biomass of 20 g/l at pH 7.0 after 144 h. The results were also plotted in Langmuir and Freundlich isotherms and the data were well fitted. The sorption capacity was evaluated as 1.43 mg/g for the Langmuir isotherm and 1.01 mg/g for the Freundlich isotherm. The removal efficiency was, however, noted to be maximum (87.5%) at pH 6.5. The effect of biomass quantity has also been investigated along with some metabolic parameters.     

Conference reports

The aim of the study was to observe the effect of Cd on the activity of chymotrypsin (ACHT) and trypsin (AT) in droppings of Japanese quails. The birds (24) were divided into four groups of six subjects each. The animals in group 1 received 0.12 mg Cd/d in drinking water, whereas those in group 2 were given 4 mg Zn/d. The quails in group 3 were supplied a combination of 0.12 mg Cd/day and 4 mg Zn/d. The quails in group 4 were not given any supplements, acting as controls. ACHT and AT were determined after 35 and 58d of supplementation. The addition of Cd in drinking water resulted in inhibition of ACHT and AT (p < 0.001) in group G1 in comparison to the control. Zinc showed a positive effect (p < 0.001) on the increase of ACHT and AT in groups 2 and 3. The significantly higher (p < 0.001) ACHT and AT were observed in group G3 with addition of Cd and Zn than in group G1 with addition of Cd. Our results indicated that long‐term supplementation of Zn can have a positive effect on ACHT and AT in droppings of Japanese quails.     

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.     

Monitoring and modelling of manually-controlled Venetian blinds in private offices: a pilot study

This study presents results from a window blind usage survey and field study that was conducted in California, USA during a period spanning from the vernal equinox to the winter solstice. A total of 113 office building occupants participated in the survey. Twenty-five occupants participated in the field study. In this study, 83 measurements of physical environmental conditions were cross-linked with participants' window blind controlling preferences. A total of 13 predictive window blind control bivariate and multivariate logistic models were derived. As hypothesised, the probability of a window blind closing event increased as the magnitude of physical environmental and confounding factors increased (p < 0.01). The main predictors were window/background luminance level and vertical solar radiation at the window. The confounding factors included MRT, direct solar penetration and participants' self-reported sensitivity to brightness. The results showed that the models correctly predict between 72–89% of the observed window blind control behaviour. This research extends the knowledge of how and why building occupants manually control window blinds in private offices, and provides results that can be directly implemented in energy simulation programs.     

Conductive heating and microwave hydrolysis under identical heating profiles for advanced anaerobic digestion of municipal sludge

Microwave (2.45 GHz, 1200 W) and conventional heating (custom pressure vessel) pretreatments were applied to dewatered municipal waste sludge (18% total solids) using identical heating profiles that span a wide range of temperatures (80–160 °C). Fourteen lab-scale semi-continuous digesters were set up to optimize the energy (methane) output and sludge retention time (SRT) requirements of untreated (control) and thermally pretreated anaerobic digesters operated under mesophilic and thermophilic temperatures. Both pretreatment methods indicated that in the pretreatment range of 80–160 °C, temperature was a statistically significant factor (p-value < 0.05) for increasing solubilization of chemical oxygen demand and biopolymers (proteins, sugars, humic acids) of the waste sludge. However, the type of pretreatment method, i.e. microwave versus conventional heating, had no statistically significant effect (p-value >0.05) on sludge solubilization. With the exception of the control digesters at a 5-d SRT, all control and pretreated digesters achieved steady state at all three SRTs, corresponding to volumetric organic loading rates of 1.74–6.96 g chemical oxygen demand/L/d. At an SRT of 5 d, both mesophilic and thermophilic controls stopped producing biogas after 20 d of operation with total volatile fatty acids concentrations exceeding 1818 mg/L at pH <5.64 for mesophilic and 2853 mg/L at pH <7.02 for thermophilic controls, while the pretreated digesters continued producing biogas. Furthermore, relative (to control) organic removal efficiencies dramatically increased as SRT was shortened from 20 to 10 and then 5 d, indicating that the control digesters were challenged as the organic loading rate was increased. Energy analysis showed that, at an elevated temperature of 160 °C, the amount of methane recovered was not enough to compensate for the energy input. Among the digesters with positive net energy productions, control and pretreated digesters at 80 °C were more favorable at an SRT of 10 d.     

Dégradation des eaux de rejets issues d’une raffinerie d’huile de coton par plasma d’arc électrique rampant à pression atmosphérique

Wastewater samples from liquid effluents of cotton oil refinery in Far-Northern Cameroon were exposed to a gliding arc discharge for various exposure times in a cold plasma reactor. The analysed results showed high levels of organic pollution parameters (TOC = 4635 mg/L, COD = 6943, 98 mg/L) before treatment. More than 56% TOC and 75% COD abatement were obtained after 30 min treatment in batch conditions with a laboratory reactor. The resultant pollution abatement is attributed both to strong oxidizing effects of °OH and NO° radicals formed in the plasma and their derivatives (H₂O₂, ONO₂H and NO₃H). The conductivity and TDS increase linearly and the pH, TOC and COD decrease with increasing exposure time to the discharge. The oxidation obeys a pseudo first-order kinetics law (kinetic rate: k_1DCO = 0, 0381 min^?1 and k_1COT = 0, 0245 min^?1).     

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.     

Acute toxicity test using cyanide on Daphnia magna by flow-through system

This study describes the acute toxicity of sodium cyanide on the crustacean Daphnia magna (Cladocera). A new flow-through system was innovated in which the microorganism continuously exposure to the toxicity of sodium cyanide during the test. We used twelve different concentration of sodium cyanide from low values (0 mg CN/L) to high values (1 mg CN/L) on bioassay test. D. magna were exposed to the concentrations for 24, 48, 72 and 96 h at 20–25°C. We controlled the three important parameters such as temperature, pH and DO to meet the standard requirements. The LC₅₀ values for 24, 48, 72 and 96 h (95% confidence limits in parentheses) were estimated statistically by the probit methods and were 0.171 (0.163–0.179), 0.12 (0.112–0.128), 0.07 (0.062–0.078) and 0.019 (0.011–0.027) mg/L respectively. Finally, we proposed two new values for SAR (safe application rate) and SAFE Coefficients.     

Effects of lead toxicity on the total chlorophyll content and growth changes of the aquatic plant Ceratophyllum demersum L.

This paper reports results of a laboratory-scale experiment conducted to determine the effects of different initial concentrations of a toxic heavy trace metal (lead) on the total chlorophyll (a + b) content of aquatic plant tissues Ceratophyllum demersum L., and also to monitor the visible growth changes during the experiment under different lead concentrations (2, 4 and 6 mg/L), as well as in control plants (without any addition of lead nitrate solution). Lead concentrations in water and plant samples were determined using AAS, where the total chlorophyll content in plant leaf tissues was measured every 15 days during the experimental period using a UV/VIS Spectrophotometer, Model 160A, Shimadzu, with wavelengths of 665 and 649 nm. The results showed that the content of total chlorophyll decreased noticeably, with increasing initial concentrations of lead throughout the exposure time. Decreases in total chlorophyll content in the tissues of C. demersum over the period of the experiment were accompanied by different morphological changes in the plants, depending on the initial lead concentration and exposure duration. These changes in morphology and growth affected the number and length of branches, the number of leaves and the number of leaflets.