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Screening cytotoxic potential of henna based hair dyes using human red blood cells.
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Nawalage, N.M.S.K.; Pathiratne, A.
Intensive usage of commercial hair dyes all over the world may lead to wide variety of health and environmental problems. Direct contact of hair dyes with the human skin may initiate toxic effects on human cells. Commercially available ‘henna based hair dyes’ are considered as less toxic but scientifically based studies on assessing toxicity of these dyes are limited. The present study was conducted to screen potential cytotoxicity of three selected henna based hair dyes on human red blood cells (RBC) in vitro using hemolysis assay. Mostly used henna based commercial hair dyes were purchased from the market. The hemolysis assay was performed by separating serum of the centrifuged blood samples and diluting the RBCs to 20% by adding phosphate buffered saline solution (pH 7.4). The diluted red blood cell suspensions were mixed with commercial hair dye solutions (final dye concentrations 0, 0.05, 0.1, 0.2, 0.4, 1.0 mg/mL) and the mixtures were incubated at 37OC. The incubated RBC samples were centrifuged and the absorbance of supernatants were measured at 540 nm to determine percentage hemolysis. The potential associations between dye concentration and hemolysis potential were analyzed using Pearson’s correlation test (P < 0.05). Triton X -100 (0.1%) and phosphate buffer solution (pH 7.4) were used as the positive control and the negative control respectively. Results showed significant positive correlations (P < 0.05) between hemolysis (%) and the hair dye concentration in all three hair dyes indicating concentration dependent cytotoxic response on red blood cells. The results may indicate potential health impacts associated with these henna based commercial hair dyes during direct applications at high doses. Further toxicity assessments especially in relation to cytogenetic effects are warranted considering human health.
Cytogenotoxicity screening of source water, wastewater and treated water of drinking water treatment plants using two in vivo test systems: Allium cepa root based and Nile tilapia erythrocyte based tests
(Pergamon., 2017) Hemachandra, C.K.; Pathiratne, A.
Biological effect directed in vivo tests with model organisms are useful in assessing potential health risks associated with chemical contaminations in surface waters. This study examined the applicability of two in vivo test systems viz. plant, Allium cepa root based tests and fish, Oreochromis niloticus erythrocyte based tests for screening cytogenotoxic potential of raw source water, water treatment waste (effluents) and treated water of drinking water treatment plants (DWTPs) using two DWTPs associated with a major river in Sri Lanka. Measured physico-chemical parameters of the raw water, effluents and treated water samples complied with the respective Sri Lankan standards. In the in vivo tests, raw water induced statistically significant root growth retardation, mitodepression and chromosomal abnormalities in the root meristem of the plant and micronuclei/nuclear buds evolution and genetic damage (as reflected by comet scores) in the erythrocytes of the fish compared to the aged tap water controls signifying greater genotoxicity of the source water especially in the dry period. The effluents provoked relatively high cytogenotoxic effects on both test systems but the toxicity in most cases was considerably reduced to the raw water level with the effluent dilution (1:8). In vivo tests indicated reduction of cytogenotoxic potential in the tested drinking water samples. The results support the potential applications of practically feasible in vivo biological test systems such as A. cepa root based tests and the fish erythrocyte based tests as complementary tools for screening cytogenotoxicity potential of the source water and water treatment waste reaching downstream of aquatic ecosystems and for evaluating cytogenotoxicity eliminating efficacy of the DWTPs in different seasons in view of human and ecological safety.
Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of industrial effluents originated from different industrial activities
(Springer International Publishing., 2015) Pathiratne, A.; Hemachandra, C.K.; De Silva, N.
Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of treated effluents originated from four types of industrial activities (two textile industries, three rubber based industries, two common treatment plants of industrial zones, and two water treatment plants) was assessed. Physico-chemical parameters including the heavy metal/metalloid levels of the effluents varied depending on the industry profile, but most of the measured parameters in the effluents were within the specified tolerance limits of Sri Lankan environmental regulations for discharge of industrial effluents into inland surface waters. In the A. cepa test system, the undiluted effluents induced statistically significant root growth retardation, mitosis depression, and chromosomal aberrations in root meristematic cells in most cases in comparison to the dilution water and upstream water signifying effluent induced cytotoxicity and genotoxicity. Ethyl methane sulphonate (a mutagen, positive control) and all the effluents under 1:8 dilution significantly induced total chromosomal aberrations in root meristematic cells in comparison to the dilution water and upstream water indicating inadequacy of expected 1:8 dilutions in the receiving waters for curtailing genotoxic impacts. The results support the use of a practically feasible A. cepa test system for rapid screening of cytotoxicity and genotoxicity of diverse industrial effluents discharging into inland surface waters.

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