An assessment of the fate, behaviour and environmental risk associated with sunscreen TiO₂ nanoparticles in UK field scenarios

The fate of Ti was examined in an activated sludge plant serving over 200,000 people. These studies revealed a decrease of 30 to 3.2 μg/L of Ti < 0.45 μm from influent to effluent and a calculated Ti presence of 305 mg/kg DW in wasted sludge. Thus, using sludge as a fertiliser would result in a predicted deposition of up to 250 mg/m² of Ti to soil surfaces using a recommended maximal agricultural application rate. Given the major use of TiO₂ in many industrial and domestic applications where loss to the sewer is possible, this measured Ti was presumed to have been largely TiO₂, a proportion of which will be nanoparticle sized. To assess the behaviour of engineered nanoparticle (ENP) TiO₂ in sewage and toxicology studies, Optisol (Oxonica Materials Ltd) and P25 (Evonik Industries AG), which are representative of forms used in sunscreen and cosmetic products, were used. These revealed a close association of TiO₂ ENPs with activated sludge. Using commercial information on consumption, and removal rates for sewage treatment, predictions were made for river water concentrations for sunscreen TiO₂ ENPs for the Anglian and Thames regions in Southern England. The highest predicted value from these exercises was 8.8 μg/L for the Thames region in which it was assumed that one in four people used the recommended application of sunscreen during a low flow (Q95) period. Ecotoxicological studies using potentially vulnerable species indicated that 1000 μg/L TiO₂ ENP did not affect the viability of a mixed community of river bacteria in the presence of UV light. Direct exposure to TiO₂ ENPs did not impair the immuno-effectiveness of earthworm coelomocyte cells at concentrations greatly above those predicted for sewage sludge.     

Educational legislation and reprogramming for environmental protection — a viewpoint

Laws not backed by a broad educational approach run the risk of not being very effective, particularly when aimed at prevention rather than at repression and/or punishment. For instance, in countries such as Belgium, where training and education programmes are noticeably narrowly legislated towards legal “accreditation”, it is consequently of paramount importance that “éducation à l'environment"(educating for the environment) be embodied in “legal texts”. Hence curricula ought to be set to cover environmental problems, and to nurture respect for such environment. Lip service will not do. Punish the polluter will not suffice. It is students and pupils, and the public at large, that have to be made aware of civic responsibility.     

Toxicological and environmental implications on the use of nitrilotriacetic acid as a detergent builder—1

Phosphates are unique as causal nutrients in the induction of cultural eutrophication; they are not only critical and growth limiting, but also controllable. Detergents currently constitute 50–70% of phosphates in municipal sewage. Partial substitution of polyphosphate detergent builders by nitrilotriacetic acid NTA has been proposed in an attempt to reduce or reverse eutrophication. Biodegradation of NTA is variable and can be markedly retarded under a wide range of operating field conditions. In model studies, NTA is a strong chelating agent; biodegradation of some heavy metal chelates may be delayed in both model and field studies. There are no available data on the intermediary pathways of biodegradation of NTA; hypothetical pathways based on sequential degradation via secondary amines, primary amines, ammonia, and nitrite and nitrate are proposed. Estimates are made on NTA and nitrate levels to be expected in water under a wide range of conditions; the possibility of human toxic effects due to nitrate increments resulting from NTA degradation, and of the involvement of NTA in nitrosamine synthesis is discussed.     

The influence of dissolved and surface-bound humic acid on the toxicity of TiO₂ nanoparticles to Chlorella sp

NOM is likely to coat TiO₂ nanoparticles (nano-TiO₂) discharged into the aquatic environment and influence the nanotoxicity to aquatic organisms, which however has not been well investigated. This study explored the influence of nanoparticle surface-bound humic acid (HA, as a model NOM) as well as dissolved HA on the toxicity of nano-TiO₂ to Chlorella sp., with a specific focus on adhesion of the nanoparticles to the algae. Results showed that nano-TiO₂ and the dissolved HA could inhibit the algal growth with an IC₅₀ of 4.9 and 8.4 mg L⁻¹, respectively, while both dissolved and nanoparticle surface-bound HA could significantly alleviate the algal toxicity of nano-TiO₂. IC₅₀ of nano-TiO₂ increased to 18 mg L⁻¹ in the presence of 5 mg L⁻¹ of the dissolved HA and to 48 mg L⁻¹ as the result of surface-saturation by HA. Co-precipitation experiment and transmission electron microscopy observation revealed that both dissolved and nanoparticle surface-bound HA prevented the adhesion of nano-TiO₂ to the algal cells due to the increased electrosteric repulsion. The generation of intracellular reactive oxygen species (ROS) was significantly limited by the dissolved and nanoparticle surface-bound HA. The prevention of adhesion and inhibition of ROS generation could account for the HA-mitigated nanotoxicity.     

The influence of capsular extracellular polymeric substances on the interaction between TiO₂ nanoparticles and planktonic bacteria

The role of capsular extracellular polymeric substances (EPS) at the surface of planktonic microorganisms was investigated for possible toxicity mitigation from titanium dioxide (TiO₂) nanoparticles, using variable EPS producing wild-type and isogenic mutant strains of Pseudomonas aeruginosa. Membrane integrity assays revealed that increased capsular EPS reduced cell membrane damage. Acting as a barrier to the cell membrane, capsular EPS permitted attachment of nanoparticles to the cell, while simultaneously delaying cellular damage caused by the production of reactive oxygen species (ROS). Modulations in ROS production were monitored in situ; while changes in the chemical composition of the microorganisms before and after exposure were examined with Fourier transform infrared spectroscopy (FTIR). The addition of methanol, a known radical scavenger, was shown to vastly reduce ROS production and membrane integrity losses, while not affecting physical interactions of nanoparticles with the microorganism. The results support that EPS provides an attachment site for nanoparticles, but more importantly act as a barrier to cell membrane oxidation from ROS. These observations provide better understanding of the overall importance of ROS in TiO₂ microbial toxicity.     

Review and Exploration of the Development of Planning for the Conservation of the Famous Historical and Cultural Cities in China

To comprehend the development of the famous histori-cal and cultural cities in China and their conservation plan-ning, it is necessary to understand, first of all, the back-ground of their history and present condition. This back-ground has taken shape in the historic development of thecities and is influenced by many complicated factors of thepresent time. To discuss these factors in simple way, theycan be summarized as follows:The impact of the historical and cultural ideas;The impact of the physical and environmental condi-tion;The impact of the present socialand economicsituation.The impact of the historical and cultural ideasChina is a country with ancient civilization. TheChinese cultural has been shaped through development, in-heritance and harmony in a history of 5000 years on the ba-sis of the ancient Huaxia Culture with the Yellow River andthe Yangtse River as the main arteries.The rising of ancient cities in China can be traced backto over 3500 years ago. China is a multinational country. Int     

Integration of GC-MSD and ER-Calux® assay into a single protocol for determining steroid estrogens in environmental samples

There are many published studies that use either chemical or biological methods to investigate steroid estrogens in the aquatic environment, but rarer are those that combine both. In this study, gas chromatography with mass selective detection (GC-MSD) and the ER-Calux^® estrogenicity assay were integrated into a single protocol for simultaneous determination of natural (estrone — E1, 17β-estradiol — E2, estriol — E3) and synthetic (17α-ethinylestradiol — EE2) steroid estrogens concentrations and the total estrogenic potential of environmental samples. For integration purposes, several solvents were investigated and the commonly used dimethyl sulphoxide (DMSO) in the ER-Calux^® assay was replaced by ethyl acetate, which is more compatible with gas chromatography and enables the same sample to be analysed by both GC-MSD and the ER-Calux^® assay. The integrated protocol was initially tested using a standard mixture of estrogens. The results for pure standards showed that the estrogenicity calculated on the basis of GC-MSD and the ER-Calux^® assay exhibited good correlation (r² = 0.96; α = 0.94). The result remained the same when spiked waste water extracts were tested (r² = 0.92, α = 1.02). When applied to real waste water influent and effluent samples the results proved (r² = 0.93; α = 0.99) the applicability of the protocol. The main advantages of this newly developed protocol are simple sample handling for both methods, and reduced material consumption and labour. In addition, it can be applied as either a complete or sequential analysis where the ER-Calux^® assay is used as a pre-screening method prior to the chemical analysis.     

Housing Policy as a Lever for Change? The Politics of Welfare,Assets and Tenure

The housing tenure structure has long been associated with different forms of welfare state capitalism in Western Europe. However, with the rise of owner-occupancy, this association has not been so straightforward. An alternative view is to view housing policies that promote owner-occupancy for households to acquire assets, as an attempt by the state to reform social welfare systems. The politics of welfare reform are related to the discourses of homeownership ideology. The ownership of (housing) assets agenda serves as a means to change the relationship between state, market and individual households. This view is mostly based on the British experience and this paper seeks to broaden it by examining the Netherlands and Spain. The paper shows differences, but also that housing policies play an important role in driving towards or maintaining market-dominated solutions. Housing is used to either reorient towards or maintain a welfare system where asset ownership and market dependency is deemed more appropriate than secure income and public expenditure.     

Dynamic and real-time simulation of BMS and air-conditioning system as a ‘living’ environment for learning/training

Dynamic and real-time simulation models are developed to simulate the thermal, hydraulic, mechanical, environmental and energy performance of building a variable air volume (VAV) air-conditioning system and its building management system (BMS). On-line direct digital control (DDC) and supervisory strategies of the BMS controlling the dynamic air-conditioning system are simulated. A window-based users interface is developed to simulate the man–machine interface of a BMS, through which users can monitor the on-line operation, tune the local control loops, and reset the supervisory control strategies. This paper presents models, simulation software, and examples that users practice on the simulated on-line BMS and air-conditioning system using the software.     

Polluting facilities and environmental justice – a study

The environmental justice movement attempts to examine the disproportionate exposure of environmental pollution on minority and low‐income people, understand the patterns of such disproportionate exposures and develop strategies to reduce and eliminate such exposures. Unlike several environmental justice studies that include all fifty states of the United States, this study examines the locations of manufacturing facilities that pollute in states with predominantly high African‐American populations. Our analysis indicates that polluting facilities tend to choose counties with higher proportion of nonwhite populations. Per capita incomes of people living within 5‐miles of the facilities are lower than per capita incomes of people living in the host counties Contrary to the conventional wisdom, population density per square mile both within 1 mile and 5 miles of the facility are much higher than the state population densities.     

Development of cork–gypsum composites for building applications

This paper presents an experimental analysis on a new composite material, cork–gypsum composite. It is shown that cork and plaster are mutually compatible and that a lot of new building materials can be made by mixing those materials in different volume fractions. Mechanical properties of the cork–gypsum composite have been measured. The acoustic absorption coefficient and thermal conductivity of this new composite have also been experimentally obtained and those values are reported for design purposes. Concerning the acoustical insulation characteristics, this composite is not a sound-absorbing material but a reflecting one, and it needs some kind of perforations to behave as an absorbing construction material for sound and noise. The thermal insulation properties are quite good as a result of the thermal conductivity tests. This new composite material is suggested for use in building applications as partitions.     

Moscow’s jurassic clayey soils as a medium for the installation of underground structures and deep trenches

Moscow’s Jurassic clayey loams, which are frequently media for the installation of underground structures and deep trenches, are examined. Archival survey data are processed statistically, and correlation relations between strength characteristics of the soils and physical characteristics are investigated using the theory of correlation-regression analysis. Extremely close relations are established between strength characteristics and physical parameters. Interrelation equations are derived for prediction of strength characteristics of the Jurassic clayey soils in designing underground structures and the enclosing structures of deep trenches. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 18–20, March–April, 2000.     

Quo vadis source tracking? Towards a strategic framework for environmental monitoring of fecal pollution

Advances in microbial source tracking (MST) have largely been driven by the need to comply with water quality standards based on traditional indicator bacteria. Recently, a number of culture-independent, and library-independent methods based on polymerase chain reaction (PCR) have been gaining popularity among source trackers. However, only a limited number of these methods have been successfully used in field applications, primarily due to the fact that many of them are still being developed. In this critical outlook, we examine different viewpoints associated with the practical use of MST to identify critical research gaps, propose a priority-based timeline to address them, and outline emerging technologies that will likely impact the future of source tracking. We propose that it is necessary to consider each of these aspects in order to advance towards a unifying framework in source identification, so that fecal pollution monitoring can be reliably used for comprehensive environmental microbial monitoring, to develop risk assessment models, and to implement and validate adequate management practices.     

Swedish Pasture—An Exploration of Perceptual Attributes and Categorisation

Abstract

This study explores the concept of pasture, looking at how people classify it and the features that determine how an image is classified. The analysis is based on two parallel studies that used the same image material. The first study was a web-based survey in which respondents were asked to make a pairwise comparison of the images they felt best corresponded to pasture. The second study used eye-tracking to investigate the elements viewed by respondents as they considered the degree to which images corresponded to pasture. It is found that the respondents had clear and mostly similar concepts of pasture and that they apply these consistently when categorising pasture.     

Use of impulse radar as a method for the non‐destructive testing of concrete slabs

The paper shows that Impulse Radar provides engineers and associated professions with an invaluable non‐destructive testing tool and when used in conjunction with other methods of testing, Impulse Radar has an important role to play throughout the complete lifecycle of a structure.     

Children's blood lead and exposure to lead in household dust and water — a basis for an environmental standard for lead in dust

Good quantitative evidence on the role of lead in household dust as a source of exposure to children has been lacking. A study of 495 children in Edinburgh, Scotland shows a significant relationship between lead in dust vacuumed from the floors of the children's homes and their blood lead levels. A multiple regression analysis incorporating drinking water and household dust estimates that a 1,000 μg g⁻¹ increase in dust lead concentration would increase blood lead by 1.9 μg dl⁻¹, for a child with the median population blood lead of 10.1 μg dl⁻¹. Dust lead concentration is a more useful predictor of blood lead than lead loading. The sanding or blow-lamp stripping of old paint is found to be an important source of the higher household dust lead concentrations. Finally, the dust lead-blood lead relationship is used to derive a standard for lead in house dust, as no such standard exists for this exposure route.     

An Exploration of the Thinking and Method of the Revision of Beijing''''s Master Planning

This article introduces the new thinking andmethod of the revision of Beijing's master plan.The plannersmade new exploration and breakthroughs in such aspects asthe involvement of the general public in planning,the intro-duction of value concept,unified planning of both urban andrural areas,how to link with the future goals of development,etc.     

Choice of solar collector for applications below 100°C

Non-tracking collectors are the important technology options to harness the solar thermal energy at temperatures below 100°C. Thermal energy below this level has very wide applications in the residential and industrial sectors. Also, energy at this level can be used indirectly to produce cooling, fresh water or electricity. Flat plate and evacuated tube collectors with different design, configuration and cost were considered and their energy collection capabilities were estimated under the Kuwaiti conditions for different applications identified with the temperature. Based on the manufacturers' quotations and other economic parameters, the annual amortized cost of solar collectors were estimated. These values were used to estimate the system cost per unit of energy generation. A domestic solar water heater with an unglazed collector is the only solar system having economic viability at present. Evacuated tube collectors stand a good chance of being economically viable in future with increase in fuel prices and/or reduction in system cost.     

Efficient removal of microcystin-LR by UV-C/H₂O₂ in synthetic and natural water samples

The destruction of the commonly found cyanobacterial toxin, microcystin-LR (MC-LR), in surface waters by UV-C/H₂O₂ advanced oxidation process (AOP) was studied. Experiments were carried out in a bench scale photochemical apparatus with low pressure mercury vapor germicidal lamps emitting at 253.7 nm. The degradation of MC-LR was a function of UV fluence. A 93.9% removal with an initial MC-LR concentration of 1 μM was achieved with a UV fluence of 80 mJ/cm² and an initial H₂O₂ concentration of 882 μM. When increasing the concentration of MC-LR only, the UV fluence-based pseudo-first order reaction rate constant generally decreased, which was probably due to the competition between by-products and MC-LR for hydroxyl radicals. An increase in H₂O₂ concentration led to higher removal efficiency; however, the effect of HO scavenging by H₂O₂ became significant for high H₂O₂ concentrations. The impact of water quality parameters, such as pH, alkalinity and the presence of natural organic matter (NOM), was also studied. Field water samples from Lake Erie, Michigan and St. Johns River, Florida were employed to evaluate the potential application of this process for the degradation of MC-LR. Results showed that the presence of both alkalinity (as 89.6-117.8 mg CaCO₃/L) and NOM (as ∼2 to ∼9.5 mg/L TOC) contributed to a significant decrease in the destruction rate of MC-LR. However, a final concentration of MC-LR bellow the guideline value of 1 μg/L was still achievable under current experimental conditions when an initial MC-LR concentration of 2.5 μg/L was spiked into those real water samples.     

Surface neutralization and H₂S oxidation at early stages of sewer corrosion: influence of temperature, relative humidity and H₂S concentration

While the involvement of a range of environmental factors in sewer corrosion is known, a comprehensive understanding of the processes involved and the exact role of individual environmental factors in sewer corrosion is still lacking. The corrosion of concrete in sewer systems is reported to be initiated through chemical reactions (involving H₂S and CO₂) that lower the surface pH to a level then conducive for biological activity. However, the specific influence of environmental variables, such as H₂S level, temperature, and relative humidity etc. remains unclear; although, they are expected to control these initial surface reactions of the concrete sewer pipe. We examined changes in the surface chemistry of concrete during the early stages of corrosion by exposing concrete coupons to thirty-six independent conditions in well-controlled laboratory chambers that simulated conditions typically found in various sewer environments across Australia. The conditions employed were combinations of six H₂S levels, three gas-phase temperatures and two relative humidity levels. Our results indicate that the role of CO₂ on initial surface pH reduction is insignificant when compared to the influence of H₂S. Within the first 12 months, a decrease in surface pH by 4.8 units was observed for coupons exposed to 30 °C and 50 ppm H₂S, while significantly lower pH reductions of 3.5 and 1.8 units were detected for coupons exposed to 25 °C and 18 °C respectively, and 50 ppm H₂S. Elemental sulphur was found to be the major oxidation product of H₂S and elevated concentrations were detected at the higher levels of H₂S, temperature and relative humidity. More significantly, the data obtained from the controlled chamber experiments correlated with those obtained from the field-exposed coupons. Hence, these findings can be extended to real sewer corrosion processes.