Coffee,its roasted form,and their residues cause birth failure and shorten lifespan in dengue vectors

Environmental Science and Pollution Research - In dengue mosquitoes, successful embryonic development and long lifespan are key determinants for the persistence of both virus and vector. Therefore,...     

Composition and distribution of surfactants around Lake Chini,Malaysia

This study aims to determine the composition of surfactants in the lake surface microlayer, rainwater, and atmospheric aerosols in the area surrounding Lake Chini, Pahang. Surfactants in the lake surface microlayer were taken from seven different stations around the lake, while samples of rainwater were taken from five different sampling stations. The samples of atmospheric aerosols were collected from the Lake Chini Research Centre which is in close proximity to the lake. The colorimetric analysis method was used to determine the composition and concentration of anionic surfactants as methylene blue active substances (MBAS) and cationic surfactants as disulphine blue active substances (DBAS). The concentration of anionic surfactants, as MBAS, in the surface microlayer ranged between 0.08 to 0.23 μmol L^− 1, while the range of concentration of cationic surfactants as DBAS ranged from 0.09 to 0.11 μmol L^− 1. The concentration of MBAS was higher in rainwater when compared to surfactants in the lake surface microlayer. The high concentration of surfactants in the fine mode of atmospheric aerosols suggests that natural and anthropogenic sources of surfactants contribute to the atmospheric surfactants.     

Heavy metal concentrations in water and sediments in Tasik Chini, a freshwater lake, Malaysia

The purpose of this paper are to determine the concentration of heavy metals namely cadmium (Cd), copper (Cu) and lead (Pb) in water and sediment; and to investigate the effect of sediment pH and sediment organic matter on concentration of cadmium, copper and lead in sediment at oxidation fraction. For this purpose the concentration of heavy metals were measured in water and sediments at 15 sites from Tasik Chini, Peninsular Malaysia. The sequential extraction procedure used in this study was based on defined fractions: exchangeable, acid reduction, oxidation, and residual. The concentration of heavy metals in residual fraction was higher than the other fractions. Among the non-residual fractions, the concentration of heavy metals in organic matter fraction was much higher than other fractions collected from all sampling sites. The pH of the sediment in all sites was acidic. The mean pH ranges from 4.8 to 5.5 with the higher value observed at site 15. Results of organic matter analysis showed that the percentage of organic matter present in sediment samples varies throughout the lake and all sites of sediments were relatively rich in organic matter ranging from 13.0% to 34.2%. The highest mean percentage of organic matter was measured at sampling site 15, with value of 31.78%.     

Psychosocial safety climate: Conceptual distinctiveness and effect on job demands and worker psychological health

Psychosocial safety climate is an emerging construct that refers to shared perceptions regarding policies, practices, and procedures for the protection of worker psychological health and safety. The purpose of the research was to: (1) demonstrate that psychosocial safety climate is a construct distinct from related climate measures (i.e., physical safety climate, team psychological safety, and perceived organizational support); and (2) test the proposition that organizational psychosocial safety climate determines work conditions (i.e., job demands) and subsequently worker psychological health. We used samples from two different cultures; an Australian sample (N = 126 workers in 16 teams within a primary health care organization) and a Malaysian sample (N = 180 workers in 31 teams from different organizations and diverse industries). In both samples confirmatory factor analysis verified that psychosocial safety climate is a construct distinct from related climate measures. Using hierarchical linear modeling, psychosocial safety climate was superior to other team level climate measures in its negative relationship to both job demands and psychological health problems. Results supported a mediation process, psychosocial safety climate → job demands → psychological health problems, corroborating psychosocial safety climate as a preeminent stress risk factor, and an efficient target for intervention. We found both physical and psychosocial safety climates were stronger in the Australian, compared with the Malaysian work context. Levels of psychosocial safety climate were significantly lower than those of physical safety climate in both countries indicating a ‘universal’ lack of attention to workplace psychological health.     

Assessment of trace metals using lichen transplant from automobile mechanic workshop in Ile-Ife metropolis,Nigeria

The level of air pollution around the automobile mechanic workshops has been generally overlooked. This study, examined the level of trace metals in automobile mechanic workshops and the suitability of using transplanted lichen thalli of Lepraria incana for measuring air pollution in such areas. Samples of the lichen thalli were transplanted into seven different sites and were attached to the bark of trees at each site. The samples were harvested from the sites after 3-month exposure. Concentrations of Pb, Cu, Cd, Fe, Zn, and S content were determined using an atomic absorption spectrophotometer. Results showed that there was a significant difference in the trace metals concentrations across the sites (p?<?0.05). The analyzed lichen samples showed a range of 91.26–119.35 ppm for Fe, 30.23–61.32 ppm for Zn, 1.25–2.45 ppm for Cu, 0.017–0.043 ppm for Cd, 0.018–0.051 ppm, and 0.37–0.42 ppm for S. From the study, sites 6 and 7 presented higher concentrations of Cd, Pb, and Zn than other sites. The enrichment factor calculated showed that Zn, Cd, and Pb were greatly enriched from the workshops. The trend in the concentration of these heavy metals suggests that activities in these workshops might become a major source of certain heavy metals in the environment and if the pollution activities persist, it might become worrisome over time.     

Intertidal macroinvertebrate community structure in a subtropical channel is driven by sediment properties across different land-use types

Environmental Science and Pollution Research - Macroinvertebrate community in the intertidal setup plays an important role in coastal ecosystem functions and biogeochemical cycle. However,...     

Incorporation of sewage sludge in clay brick and its characterization.

This study reports the use of sewage sludge generated from sewage treatment plant (STP) as raw material in a clay brick-making process. The physico-chemical and mineralogical characterization of the sewage sludge and clay were carried out in order to identify the major technological constraints and to define the sludge pretreatment requirements if necessary. Moreover, the effects on processing conditions and/or on changes of typical final characteristics are also evaluated. Bricks were produced with sewage sludge additions ranging from 10 to 40% by dry weight. The texture and finishing of the surface of sludge-amended clay bricks were rather poor. As for the physical and chemical properties, bricks with a sludge content of up to 40 wt.% were capable of meeting the relevant technical standards. However, bricks with more than 30 wt.% sludge addition are not recommended for use since they are brittle and easily broken even when handled gently. A tendency for a general degradation of brick properties with sludge additions was observed due to its refractory nature. Therefore, sludge bricks of this nature are only suitable for use as common bricks, which are normally not exposed to view, because of poor surface finishing.     

Delonix regia and Casuarina equisetifolia as passive biomonitors and as bioaccumulators of atmospheric trace metals

The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace metals(Cd,Pb,Zn and Cu) has been evaluated.Bark and leaf samples from these plant species were collected in June and July 2006 at five locations in Benin City.Four of the sampling sites were in areas of high traffic density and commercial activities,the fifth site is a remote site,selected to act as a control and also to provide background information for the metals.The plant samples were collected and processed using standard procedures and trace metals were determined using atomic absorption spectrometer.The bark of the plants was able to bioaccumulate the trace metals,especially Pb which originates from anthropogenic contributions in the city.The Pb range of 20.00-70.00 μg/g measured for the bark samples of D.regia,exceeded the normal plant Pb concentration of 0.2-20.0 μg/g and most Pb data available in literature.The bark of the plants was observed to accumulate more metals compared to the leave,while D.regia was found to be slightly better than C.equisetifolia in trace metal uptake efficiency.Spatial variations in the distributions of Pb and Zn were significant(p 0.05),and the continuous use of leaded fuel in Nigeria was identified as the predominant source of Pb in the atmosphere.