Heavy metals in a typical city-river-reservoir system of East China: Multi-phase distribution, microbial response and ecological risk

The rapid construction of artificial reservoirs in metropolises has promoted the emergence of city-river-reservoir systems worldwide. This study investigated the environmental behaviors and risks of heavy metals in the aquatic environment of a typical system composed of main watersheds in Suzhou and Jinze Reservoir in Shanghai. Results shown that Mn, Zn and Cu were the dominant metals detected in multiple phases. Cd, Mn and Zn were mainly presented in exchangeable fraction and exhibited high bio...     

Multi-biomarker responses in green mussels exposed to PFCs: effects at molecular,cellular, and physiological levels

Perfluorinated chemicals (PFCs) are extremely persistent and have been found extensively in the environment and wildlife. Oceans are the final sink for many persistent organic pollutants (POPs) including PFCs. However, to date, there has been a lack of studies that investigated the environmental consequences of PFCs on marine organisms. To fill in this gap, environmental toxicity of two dominant PFCs, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), was examined in a sentinel species, green mussel Perna viridis, using a series of biomarkers corresponding to different biological levels (molecular, cellular, and physiological). Correlations among these biomarkers were also investigated. The results showed that the tested compounds can induce a series adverse effect at different biological levels, including oxidative stress, DNA damage, membrane instability, suppressed filtration rate, and reduced body weight. Correlation analysis revealed that excess production of reactive oxygen species could be the major toxic pathway. An indirect mode of toxic action was also explored where adverse impacts could be secondary effects of PFC exposure. The joint analysis of biomarkers from multiple biological levels resulted in a comprehensive understanding of how PFC exposure can influence the health of organisms. The correlations of these biomarkers also provided a new perspective of the ecological consequences of PFCs.     

Sustainability assessment of national rural water supply program in Tanzania

Sustainability of rural water supply programs in developing countries is still an elusive goal. It is widely accepted that, as a rule, they have failed to deliver benefits to society in the long run. Emphasis has frequently been placed on the short‐term activities. Fast production of new schemes is thus a common strategy, prioritizing the engineering component, while sidestepping social and participatory issues and community empowerment. In 2006, the Government of Tanzania launched a national program to meet water sector targets set out in the Millennium Development Goals by the year 2015. In this study we evaluate key features of the program on a sustained basis. There is evidence that the Government is promoting more sustained facilities, focusing on cost recovery and on ‘decentralization by devolution’. Nevertheless, there are several shortcomings which threaten the long‐term functionality of the infrastructure that has to be built. In light of the implementation of the program, and based on the outputs of its pilot phase, we review the factors that can determine its sustainability.     

Effect of temperature on the disappearance of four triazine herbicides in environmental waters

The influence of temperature on the disappearance of four s-triazine herbicides, terbuthylazine, simazine, atrazine and prometryn was studied in sea, river and groundwaters spiked with approx. 5 mg l(-1) of each during long-term laboratory incubation. Residues were analyzed by GC-NPD and confirmed by GC-MSD. No clean-up was necessary and a micro on-line method for the determination of herbicide residues was used. The results showed that temperature had little effect on the behaviour of the four herbicides in river and seawaters but strongly affected their behaviour in groundwater. Simazine was the most readily affected compound in sea, river and groundwaters, while terbuthylazine and atrazine were the most persistent in all cases, especially in riverwater. Half-lives ranged from 41 days (constant rate = 0.017 days(-1)) to 196 days (constant rate = 0.003 days(-1)) for simazine (40 degrees C) and terbuthylazine (20 degrees C), respectively, in riverwater. Only for terbuthylazine in riverwater was the remaining percentage at the end of the experiment higher than 50% (58%, 3.21 mg l(-1)). In the other cases, the remaining percentage varied from 4% (0.20 mg l(-1), 40 degrees C) to 43% (2.25 mg l(-1), 20 degrees C) for simazine and terbuthylazine, respectively, in groundwater.     

Monitoring trace metals in urban aerosols from Buenos Aires city. Determination by plasma-based techniques

A study was undertaken, within the framework of a 3 years national project, to assess the content of 13 elements in airborne particulate matter collected in representative zones of the metropolitan area of Buenos Aires. The sampling strategy followed consisted in collecting simultaneously 67 samples of PM10 particulate matter in 9 sampling sites covering an area of about 30 km2 during one week. The collection was performed on ash-free fibre-glass filters using high volume samplers. A combination of aqua regia and perchloric acid was used for leaching metals from filters. Key elements, namely Al, Ca, Cu, Fe, Mn, Mo, Ni, Pb, S, Sb, Sn, Zn and Zr, were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) at micro g g(-1) and ng g(-1) levels. Analyte concentration varied from 130 ng g(-1)(Mo) to over 30%(Ca). Multivariate statistical analysis was performed on the data set including the measured elemental compositions for the monitored period. The atmospheric concentration found for Pb confirms the decreasing levels of this element since the introduction of unleaded gasoline in 1995: 88 ng m(-3)(2001) < 220 ng m(-3)(1997) < 3900 ng m(-3)(1994). The average S concentration above 3 microg m(-3) is somehow unexpectedly high for Buenos Aires since the relatively low S content of liquid fuels and the massive usage of natural gas imply low emissions of this element from combustion activities. To the best of our knowledge, S concentrations are reported for the first time for this city.     

Occurrence and source characterization of perfluorochemicals in an urban watershed

Perfluorochemicals (PFCs) are used in numerous applications, mainly as surfactants, and occur ubiquitously in the environment as complex mixtures. This study was undertaken to characterize the occurrence and sources of commonly detected PFC compounds in surface waters of the Marina catchment, a watershed that drains an urbanized section of Singapore. Of the 19 target PFCs, 13 were detected with perfluorooctanoic acid (PFOA) (5-31 ng L⁻¹) and perfluorooctane sulfonate (PFOS) (1-156 ng L⁻¹) being the dominant components. Other compounds detected included perfluoroalkyl carboxylates (C7-C12) and perfluoroalkyl sulfonates (C6 and C8). Sulfonamide compounds detected 2-(N-ethylperfluorooctanesulfonamido) acetic acid (N-EtFOSAA), 2-(N-methylperfluorooctanesulfonamido) acetic acid (N-MeFOSAA), perfluorooctanesulfonamido acetic acid (FOSAA) and perfluorooctanesulfonamide (FOSA) were putative transformation products of N-EtFOSE and N-MeFOSE, the N-ethylated and N-methylated ethyl alcohol derivatives, respectively. Surface water concentrations were generally higher during dry weather than during storm water flow: the median concentrations of total PFCs in dry and wet weather were 57 and 138 ng L⁻¹ compared to 42 and 79 ng L⁻¹, respectively, at Stamford and Alexandra canal, suggesting the presence of a continuous source(s) which is subject to dilution during storm events. In rain water, median concentrations were 6.4 ng L⁻¹, suggesting rain contributed from 12-25% to the total PFC load for non-point source sites. The longitudinal concentration profile along one of the canals revealed a point source of sulfonated PFCs (PFOS), believed to originate from aqueous film-forming foam (AFFF). Sources were characterized using principal component analysis (PCA) and by plotting PFHxS/PFOA against PFOS/PFOA. Typical surface waters exhibit PFOS/PFOA and PFHxS/PFOA ratios below 0.9 and 0.5, respectively. PCA plots reveal waters impacted by “non-typical” PFC sources in Alexandra canal.     

Leaching of 2,4-D from a soil in the presence of beta-cyclodextrin: laboratory columns experiments

This study reports on the effect of the presence of beta-cyclodextrin (beta-CD) on the adsorption and mobility of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) through soil columns. The previous application of beta-CD to the soil produced a retarded leaching of 2,4-D through the soil column, due probably to herbicide adsorption on the soil through beta-CD adsorbed. However, the application of beta-CD solution to the soil column where 2,4-D had been previously adsorbed, led to the complete desorption of the herbicide, due to the formation of water-soluble 1:1 inclusion complexes between 2,4-D and beta-CD. Beta-CD can be viewed as a microscopic organic-phase extractant. It can be an advantage to remove from soil pesticides which are able to form inclusion complexes with cyclodextrins, making them possible candidates for use in in situ remediation efforts.     

Using the sustainable development goals towards a better understanding of sustainability challenges

The United Nations General Assembly agreed and approved in September 2015 the document ‘2030 Agenda for Sustainable Development’, which contains a set of measures aiming to balance economic progress and protection of the environment, whilst at the same time remain aware of the need to address the many disparities still seen between industrialised and developing countries. The Agenda document consists of 17 Sustainable Development Goals (SDGs), which among many other tasks, intend to eradicate poverty and create better health conditions in both developed and developing countries. But despite the need for and the relevance of the SDGs, it is unclear how they may help to address present and future sustainability challenges. Based on the need to shed some light on such a relationship, this paper describes each of the SDGs, and offers an analysis of the extent to which their implementation may offer support to ongoing attempts to handle some of the pressing problems seen in pursuing sustainable development. Three case studies are presented to show in practice how best the SDGs can be handled. The paper concludes that the process of implementing the SDGs offers unrivalled opportunities to advance equal opportunity and foster economic empowerment, helping countries to promote the cause of sustainable development in their territories, hence benefiting their populations.     

Occurrence of emerging organic contaminants in a tropical urban catchment in Singapore

The aim of this study was to test in a short term laboratory experiment the accumulation and physiological effects of As in the epiphytic lichen Xanthoria parietina. Arsenic content in treated samples increased progressively with increasing concentration in treatment solutions. Treatment of X. parietina thalli with 0.1, 1, 10 ppm As solutions caused significant decrease of viability, measured as intensity of respiratory activity, and damages to cell membranes, assessed by increase of electric conductivity of rinsing water and lipid peroxidation products. Soluble proteins content decreased and H₂O₂ content increased already at the lowest As concentration tested (0.01 ppm). Photosynthetic efficiency, measured in terms of F_V/F_M ratio, decreased significantly only at the highest As concentration (10 ppm). It was concluded that As exposure causes physiological stress both on the mycobiont and the photobiont and that cell membrane damage, expressed in terms of electric conductivity of rinsing water, is the parameter most affected by As treatment.