Rapid ecotoxicological tests using bioassay systems: a review

The rise in pollution cases globally is expected to increase in line with industrialization. Monitoring activities for pollutants have been hampered by the astronomical costs of instrumental-based approach. This has resulted in the intense research on low cost biomonitoring systems using enzymes, organisms including microorganisms. Only positive samples are sent for instrumental analysis; dramatically cutting the cost of instrumental analysis. This review attempts to outline and give due recognition to several selected bioassay systems that have been tested for their applicability using polluted water samples as a routine first line-of-defense. This includes small aquatic organisms-based assays, enzymes especially proteases and bacterial-based systems using respiratory dye or luminescence systems as a method for toxicant detection

Chemistry, biochemistry, toxicity and pollution of molybdenum: a mini review

Molybdenum is used in various industries. Its pollution has been recorded globally and is an emerging pollutant. Molybdenum is poorly represented in the literature as compared to heavy metals such as mercury, chromium, arsenic, lead and cadmium for instance, due to the metal’s low toxicity to humans. It has now been reported that molybdenum is very toxic to embryo and spermatogenesis of fish and mice and this worrying trend would place molybdenum at the forefront of toxicology and bioremediation studies in the future. This mini review attempts to summarize what we know on its chemistry, biochemistry, toxicity and pollution with the hope that this knowledge would be useful for future studies on molybdenum’s removal from the environment

Assessment of heavy metal toxicity using a luminescent bacterial test based on Photobacterium sp. strain MIE

Toxicity evaluation of wastewater, polluted sediment and water streams is a very crucial aspect of environmental pollution monitoring. In this work, a newly developed luminescent bacterial test using a tropical luminescent bacterium, Photobacterium sp. strain MIE was used to assess the toxicity of several heavy metals using a 15-min assay format. The assessment was carried out by exposing strain MIE to different concentrations of heavy metals ranging from 0.001 to 200 mg/L in a DTX microplate 96 wells. The toxicity result based on the inhibitory concentration (IC50) was Hg (0.053 mg/L) > Ag (0.12 mg/L) > Cu (0.85 mg/L) > Ni (12.32 mg/L) > Zn (18.72 mg/L) > Cr (26.02 mg/L). Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC) analyses showed the sensitivity (IC50) of strain MIE to several toxic heavy metals are comparable to the commercial luminescent assay, Microtox™ as both clusters together making it a good choice for an alternative near-real-time monitoring of heavy metals. The sensitivity of strain MIE towards heavy metals was proven through field trial works on several heavy metal-polluted sites in Malaysia. Thus, it is a good candidate as an early detection system for heavy metals in aquatic bodies in tropical countries

Kinetic studies on the biosorption of the brominated flame retardant 4-dibromodiphenyl ether (BDE-3) using coconut palm leaf powders

Methods such as membrane isolation, ion replacements, precipitation, transformation and biosorption are proven approaches to contaminant control. Biosorption has all of these technological features including low operating costs, very efficient detoxifying of toxicities at low volumes, minimal amounts of removal components and nutrient requirement, as well as bacterial remediation, which are limited to the presence of heavy metals and other toxicants. The biosorption of BDE-3 on coconut leaves powder on the biosorption of BDE-3 from coconut leaves powder were analyzed using three models—pseudo-1st, pseudo-2nd and Elovich, and fitted using non-linear regression. Statistical analysis based on root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC) and Hannan–Quinn information criterion (HQC) showed that the Pseudo-2nd order model is the best model. Kinetic analysis using the Pseudo-2nd order model gave a value of equilibrium sorption capacity qe for 0.01 g per L adsorbent of 488.16 mg g-1 (95% confidence interval from 463.68 to 512.64) and a value of the Pseudo-2nd-order rate constant, k2 of 0.00019 (95% confidence interval from 0.00010 to 0.00027) while the equilibrium sorption capacity qe for 0.002 g per L adsorbent of 2403.61 mg g-1 (95% confidence interval from 2313.99 to 2493.22) and a value of the Pseudo-2nd-order rate constant, k2 of 0.000043 (95% confidence interval from 0.000027 to 0.000059). These calculated values will be very useful in designing effective sorption experiment and understanding the limitations of the system developed

Characterization of empty fruit bunch biochar pyrolyzed at different temperatures with respect to activated carbon and their sorption capacities for pentachlorophenol

Pentachlorophenol (PCP) has been used extensively in the wood preservation industry. It is highly persistent in the environment and toxic to living organisms. The present study investigated the effectiveness of an oil palm empty fruit bunch biochar (EFBB) pyrolyzed at 350, 550 and 650°C in adsorbing PCP as compared to a commercial activated carbon (AC). The ash content, surface area and aromaticity increased while the pore volume, cation exchange capacity, O/C and (O+N)/C molar ratios decreased as the pyrolysis temperature increased. Only the EFBB pyrolyzed at 350°C and the AC adsorbed the PCP while no PCP adsorption was observed on the EFBBs pyrolyzed at 550°C and 650°C. The Langmuir maximum adsorption capacity (Qmax) values was 6.035 mg g−1, and 126.582 mg g−1 for the 350°C EFBB and the AC, respectively. The higher porosity and more oxygenated functional groups of the EFBB pyrolyzed at 350°C EFBB could be the reason for its ability to adsorb the PCP compared to the other EFBBs. The high PCP sorption by the AC on the other hand, could be attributed to its high surface area and microporous structure

Near real-time biomonitoring of copper from an industrial complex effluent discharge site using a plant protease inhibitive assay

In this work, a temporal monitoring work for heavy metals from an effluent discharge point in the Juru Industrial Estate was carried out using the protease extracted from garlic (Allium sativum) as the principal bioassay system. Casein-Coomassie-dye binding assay method has utilized this purpose. The periodic sampling results for one day of a location in the Juru Industrial Estate showed temporal variation of copper concentration coinciding with garlic protease inhibition with the highest concentrations of copper occurring between 12.00 and 16.00 hours of between 3 and 3.5 mg/L copper. The crude proteases extracted from Allium sativum successfully detect temporal variation of copper form this location. In conclusion, this assay method has the potential to be a rapid, sensitive, and economic inhibitive assay for the large-scale biomonitoring works for the heavy metal copper from this area

Isolation and culture medium optimisation using one-factor-at-time and response surface methodology on the biodegradation of the azo-dye amaranth

Isolate JR1 was isolated from the polluted textile industry activities site in the Juru Penang area. This bacterium was characterized as a gram-positive Bacillus bacterium and also gave a positive biochemical test for catalase test and oxidase test. The isolate JR1 gave a maximum decolourization of Amaranth dye under static conditions with the rate of decolorization of 98.82%. Seven variables which are pH, temperature (°C), ammonium acetate (g/L), glucose (g/L), sodium chloride (g/L), yeast (g/L) and dye concentration (ppm) was run by using Plackett-Burman design for the effective parameter of the decolourization of Amaranth. From the seven variables, three effective variables which were ammonium acetate, glucose, and dye concentration were further optimized by using a central composite design. The optimum value of ammonium acetate concentration at 0.74 g/L, glucose concentration at 3.0 g/L and a dye concentration at 58.1 ppm gave the highest percentage of decolourization. Thus, this isolate could provide an alternate solution in removing toxic dyes from environments

Mineral contents of selected marine fish and shellfish from the west coast of Peninsular Malaysia

The study was conducted to determine the mineral contents of 20 species of marine fish and 4 species of shellfish from the west coast of Peninsular Malaysia.Overall, the contents of micro minerals in all samples were below the permissible limits; except for oyster; with copper slightly higher than the limit set by FAO/WHO (1984), but below the limit set by Malaysian Food Regulations (1985); and zinc content higher than the limit set by Malaysian Food Regulations (1985), but below the limit set by FAO/WHO (1984). Meanwhile for macro minerals, most samples contained comparable sodium contents, significantly lower of potassium contents, higher calcium contents, and extremely higher of magnesium contents compared to the common ranges reported in the literatures. All samples were good sources of micro and macro minerals and could provide multi-health benefits if consumed in recommended amounts

The modified Gompertz model demonstrates a variable growth rate between two Centella asiatica phenotypes

Centella asiatica, a weakly aromatic plant that flourishes in wet tropical and sub-tropical areas as a medicinal species since ancient times. It contained important terpenoids that impart important medicinal values. Currently, studies on the terpenoid content of various Centella asiatica phenotypes have shown not only variable content but variable growth rates of different phenotypes that can affect future selection of phenotypes. The use of mathematical growth modelling can reveal important growth constants and discriminate between faster and slower growth phenotypes. Two Centella asiatica phenotypes from South Africa is modelled using the modified Gompertz model and the results showed that the C. asiatica Type-1 exhibited a faster growth rates and a shorter lag period at 0.152 day-1 and 2.313 day than another phenotype; C. asiatica Type 2 with a growth rate and a lag period of 0.067 day-1 and 3.363 day, respectively. The data indicates that different phenotypes of C. asiatica can have different growth rates and lag period and this can be important for selection of phenotypes to be used as the best bioactive peptides producer

Modelling the growth kinetics of callus cultures from the seedling of Jatropha curcas L. according to the modified Gompertz model

One of the most important preliminary investigation of callus attributes is the growth characteristics. Most often than not, callus growth curve is sigmoidal in characteristics. In this work, we model callus growth from the seedling of Jatropha curcas L. according to the modified Gompertz model from published literature to acquire essential growth constants. These growth constants can be obtained with better precision using model such as the modified Gompertz. Parameters obtained from the fitting exercise were maximum callus growth rate (μm), lag time (l) and maximal callus production (Ymax) of 0.193 d-1, 2.91 days and 0.38 g callus/25 mL culture, respectively. Growth parameter constants extracted from the modeling exercise will be helpful for additional secondary modelling implicating the consequence of media conditions as well as other factors on the growth of callus from this plant