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While production of engineered carbon nanotubes (CNTs) has escalated in recent years, knowledge of risk associated with exposure to these materials remains unclear. We report on the cytotoxicity of four CNT variants in human lung epithelial cells (A549) and murine macrophages (J774). Morphology, metal content, aggregation/agglomeration state, pore volume, surface area and modifications were determined for the pristine and oxidized single-walled (SW) and multi-walled (MW) CNTs. Cytotoxicity was evaluated by cellular ATP content, BrdU incorporation, lactate dehydrogenase (LDH) release, and CellTiter-Blue (CTB) reduction assays. All CNTs were more cytotoxic than respirable TiO2 and SiO2 reference particles. Oxidation of CNTs removed most metallic impurities but introduced surface polar functionalities. Although slopes of fold changes for cytotoxicity endpoints were steeper with J774 compared to A549 cells, CNT cytotoxicity ranking in both cell types was assay-dependent. Based on CTB reduction and BrdU incorporation, the cytotoxicity of the polar oxidized CNTs was higher compared to the pristine CNTs. In contrast, pristine CNTs were more cytotoxic than oxidized CNTs when assessed for cellular ATP and LDH. Correlation analyses between CNTs' physico-chemical properties and average relative potency revealed the impact of metal content and surface area on the potency values estimated using ATP and LDH assays, while surface polarity affected the potency values estimated from CTB and BrdU assays. We show that in order to reliably estimate the risk posed by these materials, in vitro toxicity assessment of CNTs should be conducted with well characterized materials, in multiple cellular models using several cytotoxicity assays that report on distinct cellular processes.

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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Perception of colour stimuli is found to trigger corresponding emotional and behavioural responses within human beings. Literature establishes that red is stimulating while blue is pacifying. There seems to be divided theories on how these associations are being generated. It is argued widely that colour associated emotional responses are learnt and subjective while another theory is that it is a general innate response. A third theory discusses about a combination of both learnt and innate responses. The present paper reviews literature on the above three suppositions and enlightens on a study done seeking innate, general emotional reactions triggered by colour stimuli. A questionnaire survey was conducted using guided imagination technique with a group of volunteer undergraduate students (n=86). The participants were guided to imagine five emotional/behavioural states spontaneously and recognize the corresponding colour/colours. The findings to a greater extent support the general emotional responses triggered by colour stimuli. Red and orange (79%) was dominating in their imaginations as appetizing and blue as least appetizing (60%). None (0%) imagined red as a calming colour and blue (2%) as a violent colour. The study also revealed certain learnt emotional responses. For instance, white (51%) was found to be calming, suspect to be a religiously and socially learnt emotion.

Background. Environmental surveys have characterized trace elements such as lead (Pb), cadmium (Cd) and arsenic (As) as potential risk factors for non-communicable diseases. There have been few studies conducted in the Caribbean region to explore, define or clarify such findings locally. Furthermore, local pollution control efforts are often juxtaposed against more seemingly immediate economic concerns in poor communities. Objectives. The present commentary is a call to action for the evaluation of potentially hazardous elements as potential risk indicators and/or factors of common noncommunicable diseases in the Caribbean. Discussion. Findings from Jamaican studies have identified exposure to potentially hazardous elements (PHE) via water, food, and other anthropogenic activities to the detriment of the resident population. Several attempts have been made to abate toxic metal exposure in children with relative success. However, high levels of PHE have been noted in vulnerable populations such as patients with hypertension, diabetes mellitus and chronic kidney disease. Currently, there is low priority towards infrastructure building within the Caribbean region that would promote and sustain long term monitoring and better inform environmental polices impacting chronic diseases. Conclusions. Further investigations are needed to clarify the role that PHE play in increasing the risk or progression of non-communicable diseases, especially in vulnerable groups. Competing Interests. The authors declare no competing financial interests.

Background Most pregnant or lactating women in Canada will not meet iodine requirements without iodine supplementation. Objective To assess iodine status of 132 mother-infant pairs based on secondary analyses of a vitamin D supplementation trial in breastfed infants from Montréal, Canada. Methods Maternal iodine status was assessed using breastmilk iodine concentration (BMIC). Singleton, term-born infants were studied from 1−36 mo of age. Usual (adjusted for within-person variation) iodine intakes were estimated from urinary iodine and creatinine concentrations. Iodine status was assessed using median urinary iodine concentrations (UIC) and by estimating inadequate intakes by the cut-point method using a proposed Estimated Average Requirement for infants 0−6 mo of age (72 µg/d). Results At 1, 3 and 6 mo of age, 70%, 63% and 3% of infants were exclusively breastfed, respectively. From 1−36 mo of age (n = 82−129), median UIC were ≥100 µg/L (range: 246−403 µg/L), the cutoff for adequate intakes set by the WHO for children <2 y. Almost all (98−99%) infants 1 and 2 mo, 2 and 3 mo and 3 and 6 mo of age had usual creatinine-adjusted iodine intakes ≥72 µg/d. Median BMIC was higher (p<0.001) at 1 mo compared to 6 mo of lactation: 1 mo, 198 µg/kg (IQR: 124, 274; n = 105) and 6 mo, 109 µg/kg (IQR: 67, 168; n = 78). At 1 mo 96% and at 6 mo 79% of mothers had a BMIC ≥60 µg/kg, the lower limit of a normal reference range. Percentage of mothers that used a multivitamin-mineral (MVM) supplement containing iodine was 90% in pregnancy and 79% at 1 mo and 59% at 6 mo of lactation. Conclusions Iodine status of infants was adequate throughout infancy. These results support a recommendation that all women, who could become pregnant, or women who are pregnant or breastfeeding take a daily MVM supplement containing iodine. clinicalTrials.gov identifier: NCT00381914.