Occurrence of N-nitrosamines in Alberta public drinking-water distribution systems

Since the 1974 discovery of trihalomethanes as disinfection by-products (DBPs) in drinking water, the regulatory and public health focus has been primarily directed at halogenated compounds, even though it is well established that chlorination and chloramination also produce non-halogenated DBPs. Specific halogenated DBPs that could reasonably explain the correlation of some adverse health outcomes with consumption of disinfected drinking water in a number of epidemiologic studies have yet to be identified. We therefore explored an emerging class of non-halogenated DBPs, N-nitrosamines, which warrant consideration given public health concerns regarding possible correlations of bladder cancer with exposure to chlorinated drinking water. We developed a dual media (Ambersorb® 572 and LiChrolut® EN), off-line, solid-phase extraction method that utilized a modified commercially-available extraction manifold combined with our previous GC–MS ammonia positive chemical ionization (PCI) quantitative method for analyzing N-nitrosamines in drinking water. We surveyed 20 Alberta municipal drinking-water distribution systems for the presence of N-nitrosodimethylamine (NDMA) and seven other N-nitrosamine species. Analytical results revealed the occurrence of NDMA (up to 100 ng/L) as well as two other N-nitrosamines (N-nitrosopyrrolidine and N-nitrosomorpholine) within select Alberta drinking water supplies.Key words: Alberta, chloramination, disinfection by-products, distribution system, drinking water, N-nitrosamines, NDMA, public health, survey

Biologia reprodutiva do peixe-donzela, Stegastes fuscus Cuvier, em arrecifes rochosos no nordeste do Brasil

A biologia reprodutiva do peixe-donzela, Stegastes fuscus Cuvier, 1830 (Perciforemes, Pomacentridae), foi estudada nos arrecifes rochosos da praia de Búzios, Nísia Floresta, Rio Grande do Norte, Brasil. Os peixes foram coletados mensalmente, medidos, pesados, dissecados, as gônadas foram removidas, pesadas e examinadas para identificação do sexo. Avaliação macroscópica dos estádios de maturação gonadal foi realizada. Um total de 549 exemplares foi capturado durante o período de outubro de 2004 a setembro de 2005. Foi registrada uma maior freqüência de fêmeas (78%), em relação aos machos (22%). Foi observado que 50% da população das fêmeas e dos machos iniciaram o processo de maturação gonadal com comprimento de 6,2 cm e 7,0 cm, respectivamente. Em relação à fecundidade absoluta, o número de ovócitos vitelogênicos variou entre 1790 a 14780, com média de 6832. A análise da relação gonadossomática para ambos os sexos indicou que o período de fevereiro a agosto de 2005 foi associado a um longo período de repouso gonadal. Os peixes foram considerados aptos à reprodução a partir de janeiro e em setembro-outubro com dois picos de desova registrados nesses meses, com desova do tipo parcelada. Cinco estádios de maturação gonadal foram identificados através de análises macroscópicas das gônadas: imaturo, em maturação, maduro, esgotado e repouso.<br>Reproductive biology of the damselfish, Stegastes fuscus Cuvier, 1830 (Perciformes: Pomacentridae), was studied in the coastal rocky reefs of Búzios Beach, Nísia Floresta, Rio Grande do Norte, Brazil. The fish were captured on a monthly basis, and were measured, weighed, dissected and the gonads were removed, weighed and examined in order to separate males and females. Macroscopic characterization of the stages of gonadal maturation was carried out. A total of 549 samples were captured from October 2004 to September 2005. A higher frequency of females (78%) was registered in relation to males (22%). It was observed that 50% of the population of females and males initiated gonadal maturation with a body size of 6.2 cm and 7.0 cm respectively. In relation to absolute fecundity, the number of vitelogenic oocytes ranged from 1790 to 14780, with mean of 6832. The analysis of gonadosomatic relation indicated that the period of February to August was associated to a long phase of gonadal resting in males and females. Two peaks of partial spawning were registered during January and September-October. Five stages of gonadal maturation were identified through macroscopic analysis: immature, in maturation, mature, spent and resting

Investigation of nomophobia and smartphone addiction predictors among adolescents in Turkey: Demographic variables and academic performance

Most individuals spend a great amount of time on their smartphones. The intense usage of smartphones leads to some physical symptoms, good and bad feelings, pathological addiction, depression, symptoms such as fear-anxiety, productivity and low academic achievement. For this reason, prevention activities must be prioritized when dealing with the intense and uncontrolled usage of smartphones. The aim of this study is to determine nomophobia levels and smartphone addiction among 12-18 age group secondary and high school students and to investigate the demographic and academic variables predicting these levels. Designed with a relational model, the population of this research consists of 612 students studying at all levels of secondary school and high school. Personal information form and two different scales were used in the research. Descriptive analyses and hierarchical linear multiple regression analysis were used in the analysis of the data obtained by means of data collection in the research. As a result of the research, there is a significant relationship between smartphone addiction and nomophobia. In this study, Model 4 has been identified to be the most important predictor of smartphone addiction and nomophobia. In Model 4, variables related to smartphone usage are included in the analysis. Recommendations have been made according to the results of the study. (C) 2018 Western Social Science Association. Published by Elsevier Inc. All rights reserved