多环芳烃的光致毒效应

多环芳烃（ＰＡＨｓ）是一类常见的污染物,过去对其毒性的研究主要集中在生物体内代谢产物的毒效应上。但是近期研究表明紫外光的照射对多环芳烃的毒性具有显著影响,称为ＰＡＨｓ的光致毒效应。本文介绍了多环芳烃在紫外光照射下的急性光致毒作用,致毒作用发生机理及毒性预测的数学模型,同时探讨了ＰＡＨｓ对紫外光致癌性的影响。     

Comparative phototoxicity of nanoparticulate and bulk ZnO to a free-living nematode Caenorhabditis elegans: the importance of illumination mode and primary particle size

The present study evaluated phototoxicity of nanoparticulate ZnO and bulk-ZnO under natural sunlight (NSL) versus ambient artificial laboratory light (AALL) illumination to a free-living nematode Caenorhabditis elegans. Phototoxicity of nano-ZnO and bulk-ZnO was largely dependent on illumination method as 2-h exposure under NSL caused significantly greater mortality in C. elegans than under AALL. This phototoxicity was closely related to photocatalytic reactive oxygen species (ROS) generation by the ZnO particles as indicated by concomitant methylene blue photodegradation. Both materials caused mortality in C. elegans under AALL during 24-h exposure although neither degraded methylene blue, suggesting mechanisms of toxicity other than photocatalytic ROS generation were involved. Particle dissolution of ZnO did not appear to play an important role in the toxicity observed in this study. Nano-ZnO showed greater phototoxicity than bulk-ZnO despite their similar size of aggregates, suggesting primary particle size is more important than aggregate size in determining phototoxicity.     

The toxicity of pyrene in the fish : Synergism by piperonyl butoxide and by ultraviolet light

A saturated solution of pyrene in water was not toxic to the fish , even in the presence of ultraviolet light. A survival curve possessing one minimum, and therefore defining two LC₅₀ values, was obtained when fish placed in water containing increasing amounts of a pyrene solution in dimethylsulfoxide were exposed to ultraviolet light after a short incubation period. The phototoxicity was linked to the presence of undissolved pyrene. A normal survival curve with only one LC₅₀ value was found when pyrene was solubilized with the surfactant Tween-20. Practically no phototoxicity was produced when the pyrene mixtures were filtered before use, or when a saturated aqueous solution of pyrene was used. Piperonyl butoxide, present at a concentration where it was not toxic, synergized the toxicity of pyrene . The environmental significance of this observation may be considerable.     

Photoinduced toxicity of retene to Daphnia magna under enhanced UV-B radiation

The effects of UV radiation on the acute toxicity of retene (7-isopropyl-1-methylphenanthrene) to Daphnia magna Straus were studied. Dehydroabietic acid (DHAA) from which retene is formed in the vicinity of pulp and paper industry was also studied. Pyrene, anthracene, and phenanthrene were used as model PAH compounds. The time taken for immobilization (ET50) was monitored under biologically effective UV-B dose rates of 240, 365, 565, and 650 mW m(-2) (UV-A and visible light also present). Median effective concentrations (EC50) were determined after a 15-min UV exposure (565 mW m(-2)) followed by 24 h in the dark. Retene (10-320 microg l(-1)) was not acutely toxic in the dark. The induction of phototoxicity was in agreement with the absorption properties of the compounds (absorption peak of retene at around 300 nm). Photoinduced toxicity followed an order pyrene > anthracene > retene. Phenanthrene and DHAA were not acutely phototoxic. Accumulation of the compound in Daphnia before UV exposure was essential. Some changes in the absorption spectra of the compounds were seen after a 5-h UV irradiation (565 mW m(-2)), but none of the irradiated compounds were acutely toxic without further UV exposure. Therefore, the enhanced acute toxicity was primarily due to internal photosensitization reactions rather than photomodification. The dissolved fraction of 25% pulp and paper mill effluent reduced phototoxicity by attenuating UV radiation. The phototoxicity of retene was a function of both the exposure concentration and the UV-B dose rate, but relatively high UV-B dose rates and concentrations were needed for the acute photoinduced toxicity.     

Cell size dependence of additive versus synergetic effects of UV radiation and PAHs on oceanic phytoplankton

Polycyclic Aromatic Hydrocarbons’ (PAHs) toxicity is enhanced by the presence of ultraviolet radiation (UVR), which levels have arisen due to the thinning of the ozone layer. In this study, PAHs’ phototoxicity for natural marine phytoplankton was tested. Different concentrations of a mixture of 16 PAHs were added to natural phytoplankton communities from the Mediterranean Sea, Atlantic, Arctic and Southern Oceans and exposed to natural sunlight received in situ, including treatments where the UVR bands were removed. PAHs’ toxicity was observed for all the phytoplankton groups studied in all the waters and treatments tested, but only for the pico-sized group a synergetic effect of the mixture and UVR was observed (p = 0.009). When comparing phototoxicity in phytoplankton from oligotrophic and eutrophic waters, synergy was only observed at the oligotrophic communities (p = 0.02) where pico-sized phytoplankton dominated. The degree of sensitivity was related to the trophic degree, decreasing as Chlorophyll a concentration increased.     

The phototoxicity of non-carcinogenic polycyclic aromatic hydrocarbons in aquatic organisms

Anthracene, fluoranthene, and pyrene are phototoxic in , first instar larvae of , late embryonic forms of , and fish ( ). Since polycyclic aromatic hydrocarbons are generated in the combustion processes held responsible for the damages of acid rain, and they are introduced into the environment through other means as well, the high phototoxicity of the major pollutants, which are not carcinogenic, suggests that greater attention must be given to their environmental significance.     

Assessment of the phototoxicity of weathered Alaska North Slope crude oil to juvenile pink salmon

Petroleum products are known to have greater toxicity to the translucent embryos and larvae of aquatic organisms in the presence of ultraviolet radiation (UV) compared to toxicity determined in tests performed under standard laboratory lighting with minimal UV. This study assessed the acute phototoxicity of the water accommodated fractions of weathered Alaska North Slope crude oil (ANS) to juvenile pink salmon, which are a heavily pigmented life stage. Fish in the highest ANS treatments exhibited melanosis, less mobility, reduced startle response, erratic swimming, and loss of equilibrium. Gills from fish exposed to ANS had elevated levels of hydroperoxides in oil-only, UV-only, and oil+UV treatments compared to control fish, which was indicative of increased lipid peroxidation in gill tissue. Under the test conditions of moderate salinity, low UV and high short-term oil exposure there were no indications of photoenhanced toxicity as assessed by elevation of mortality, behavioral impairment, or gill lipid peroxidation in oil+UV treatments. The results of this study suggest that pink salmon may be at less risk from photoenhanced toxicity compared to the translucent early-life stages of several other Alaska species.     

Sediment toxicity and stormwater runoff in a contaminated receiving system: consideration of different bioassays in the laboratory and field.

Several field and laboratory assays were employed below an urban storm sewer outfall to define the relationship between stormwater runoff and contaminant effects. Specifically, two bioassays that measure feeding rate as a toxicological endpoint were employed in the field and in the laboratory, along with bioassays measuring survival and growth of test organisms. In 7 to 10 d in situ exposures, amphipod leaf disc processing, growth and survival were monitored. Different exposure scenarios were investigated by varying the mesh size (74 microns or 250 microns mesh) and method of deployment (water column, sediment surface, or containing sediment) of in situ exposure chambers. Hyalella azteca, Daphnia magna, and Pimephales promelas survival were monitored in 48 h in situ exposures. Feeding inhibition was investigated via enzyme inhibition of H. azteca and D. magna and via leaf disc processing measurements of the detritivore H. azteca. Additionally, we investigated the extent of phototoxicity at this site via field exposures in sun and shade and laboratory exposures with and without UV light. The measurement of detritivore leaf disc processing, and thus its usefulness as an endpoint, was hindered by individual variability in the amount of leaf consumed and by leaf weight gain during the summer field exposures. For D. magna, enzyme inhibition measured in a laboratory exposure did not reveal the toxicity observed in field exposures. For H. azteca, enzyme inhibition measured in the laboratory indicated toxicity similar to that observed in short term chronic in situ exposures. Enzyme inhibition also did not detect differences in toxicity due to variations in flow conditions. There were no statistically significant effects of any exposure on P. promelas survival or H. azteca growth, and there were no statistically significant effects due to mesh size or sun exposure. Survival of H. azteca was the most sensitive and the least variable endpoint. Effects on survival were noted in the same treatments over short-term chronic exposures in the laboratory and in situ. Significant differences in survival were noted due to the method of deployment under low flow conditions. In situ chambers containing sediment resulted in greater mortality in the 10 d low flow in situ experiments. Under high flow conditions, significant reductions in survival and leaf disc processing were noted under all methods of deployment at the two impacted sites over a 7 d exposure. Also under high flow conditions, significantly greater mortality of H. azteca was reported at the downstream field site when sediment was included in the chamber at deployment. These results suggest that significant toxicity at this site is due to accumulation of contaminants in the sediment and the mobilization of these contaminants during a storm event. In situ exposures detected toxicity not observed in laboratory exposures. These results suggest that a combination of laboratory and field bioassays is most useful in defining field effects.     

Migration,remittances, livelihood trajectories,and social resilience

We argue that all aspects of demographic change, including migration, impact on the social resilience of individuals and communities, as well as on the sustainability of the underlying resource base. Social resilience is the ability to cope with and adapt to environmental and social change mediated through appropriate institutions. We investigate one aspect of the relationship between demographic change, social resilience, and sustainable development in contemporary coastal Vietnam: the effects of migration and remittances on resource-dependent communities in population source areas. We find, using longitudinal data on livelihood sources, that emigration and remittances have offsetting effects on resilience within an evolving social and political context. Emigration is occurring concurrently with, not driving, the expansion of unsustainable coastal aquaculture. Increasing economic inequality also undermines social resilience. At the same time diversification and increasing income levels are beneficial for resilience.     

Effects of Ni, Cr, Hg, Cu, Zn, Al on the dissolved oxygen balance of streams

Inorganic metals besides their direct toxic effects, carry the potential of causing serious variations on existing ecosystems in receiving waters. Self purification mechanism is vital for the continuity of the existing micro and macro living organisms in the streams. This mechanism is effected from the existence of metals. In this study, interferences of HgCl2, HgSO4, Ni(NO3)2, CrCl3, CuSO4.5H2O, K2Cr2O7, ZnSO4.7H2O and Al2(SO4)3.18H2O metal compounds on respirometric BOD and related effects on the self purification, are investigated with the representative formations of DO deficit curves. In the presence of these metals, streamwater BOD parameters and related DO deficit curve formations are significantly effected.     

Plastic pellets, tar, and megalitter on Beirut beaches, 1977-1988

In the spring of 1988, five beaches along the coast of Beirut were surveyed for the presence of plastic pellets, tar, and megalitter--a follow-up to the studies conducted on the coast of Lebanon in 1977 for plastic pellet and tar occurrence, and in 1978 for containers and other megalitter on Beirut beaches. Plastic pellets were more abundant than they were in 1977 on three beaches and less so on two. Tar, however, seemed to occur much more abundantly on all five beaches. Megalitter, chiefly plastic but also paper, metal, and glass, had increased greatly compared with that seen 10 years ago. As in 1977, the unrestricted waste disposal practices of the plastic manufacturers, plus the possible loss of cargo from ships loading and unloading raw materials, are the most likely sources of plastic pellets. The abundance of tar is not surprising, considering that the Mediterranean Sea is tar-polluted and that two oil terminals occur on Lebanon's coast. Further, local gas stations frequently dump oil and grease onto the beaches, and numerous fires have occurred at coastal refineries over the past 10-15 years. All of these factors are likely to contribute to the presence of tar on the beaches. The main source of the vast quantities of megalitter on the beaches is undoubtedly the Lebanese people themselves, due to numerous population shifts and the lack of order and regulatory enforcement as a result of the civil chaos in the country. In addition, the ships docking or waiting for days, and sometimes weeks, to get into the Lebanese ports probably affect the abundance of megalitter (and tar) on the beaches.     

Poverty,development, and Himalayan ecosystems

The Himalayas are rich in biodiversity but vulnerable to anthropogenic pressures. They are also host to growing number of rural poor who are dependent on forest and ecosystem services for their livelihood. Local and global efforts to integrate poverty alleviation and biodiversity conservation in the Himalayas remain elusive so far. In this work, we highlight two key impediments in achieving sustainable development in the Himalayas. On the positive side, we also highlight the work of Ashoka Trust for Research in Ecology and the Environment (ATREE), a research organization based in India that seeks to integrate biodiversity concerns with livelihood security. For impediments, we draw on two examples from the Darjeeling district, India, in Eastern Himalayan region to illustrate how development organizations are failing to simultaneously address poverty and environmental issues. Based on the success of ATREE, we then propose a conceptual framework to integrate livelihood generating activities with sustainable and equitable development agenda. We recommend developing a Hindu-Kush Himalayan Ecosystem Services Network in the region to formulate a strategy for further action. We conclude by offering measures to address the challenge of integrating livelihood and environment issues through this network.     

Evaluation of the Stone and Marble Industry in Palestine: environmental,geological, health,socioeconomic, cultural,and legal perspectives,in view of sustainable development

The Stone (limestone) and Marble (trade name) Industry (SMI) is one of the most important and active industries in Palestine, as being economically and financially rewarding and greatly beneficial to the public and private sectors. This industry, which employs about 15,000–20,000 workers, contributes 20–25% to the total industrial revenues of Palestine, and 4.5% to the total gross national product. Despite its benefits, SMI has adverse effects on public health, the environment, biodiversity, water systems (both surface and underground), green cover, and ecosystems in general, as it is considered one of the most air- water-, soil-, and noise-polluting sources. To achieve the purpose of this research paper, available data and literature are analyzed, evaluated, and used, in order to provide a comprehensive understanding of the status of SMI, in light of sustainable development. This relates to various perspectives, including limestone geology, geopolitics, socioeconomics, culture, technology, legislation, as well as climate change, acid rain, and harmful effects of the SMI scale on public health and safety, environmental well-being, and challenges facing the industry. Two field studies, carried out in northern and southern West Bank, dealing with particulate matter (PM₁, PM_2.5, PM₇, PM₁₀, and TSP) and environmental pollution, were analyzed, and their results were compared with each other, as well as with the World Health Organization’s (WHO) guidelines. It is found that both West Bank’s areas are heavily polluted, resulting in considerable adverse impacts on public health, the environment, and green cover. Based on the findings of this paper, it is recommended that SMI should properly adhere to WHO guidelines and international standards to make the industry safer and more durable and sustainable, with fewer negative impacts on public health, the environment, and green cover.

     

Trace elements, organochlorines, polycyclic aromatic hydrocarbons, dioxins, and furans in lesser scaup wintering on the Indiana Harbor Canal

During the winter of 1993-94, male lesser scaup (Aythya affinis) were collected on the heavily polluted Indiana Harbor Canal (IHC), East Chicago, IN, USA, and examined for tissue contaminant levels. Lesser scaup collected on the IHC had higher concentrations of cadmium (Cd), mercury (Hg), selenium (Se), polychlorinated biphenyls (PCBs), selected organchlorine pesticides, polychlorinated dibenzodioxins, polychlorinated dibenzofurans, polycyclic aromatic hydrocarbons, and aliphatic hydrocarbons than reference birds. Of the scaup collected on the IHC, 44% had Cd concentrations in the liver considered above background for freshwater waterfowl (>3 microg/g dry wt.), 50% had Se concentrations in the liver above a level possibly harmful to the health of young and adult birds (>33 microg/g dry wt.), and 88% of the scaup carcasses exceeded the PCB human consumption guidelines for edible poultry in the USA (>3.0 microg/g lipid wt.). The ratio of pristane:n-heptadecane concentrations in 47% of lesser scaup collected on IHC was elevated above 1.0, which is indicative of chronic exposure to petroleum hydrocarbons.     

Effects of elevated CO2, nitrogen supply and tropospheric ozone on spring wheat-II. Nutrients (N, P, K, S, Ca, Mg, Fe, Mn, Zn)

CO(2) enrichment is expected to alter leaf demand for nitrogen and phosphorus in plant species with C(3) carbon dioxide fixation pathway, thus possibly causing nutrient imbalances in the tissues and disturbance of distribution and redistribution patterns within the plants. To test the influence of CO(2) enrichment and elevated tropospheric ozone in combination with different nitrogen supply, spring wheat (Tritium aestivum L. cv. Minaret) was exposed to three levels of CO(2) (361, 523, and 639 microl litre(-1), 24 h mean from sowing to final harvest), two levels of ozone (28.4 and 51.3 nl litre(-1)) and two levels of nitrogen supply (150 and 270 kg ha(-1)) in a full-factorial design in open-top field chambers. Additional fertilization experiments (120, 210, and 330 kg N ha(-1)) were carried out at low and high CO(2) levels. Macronutrients (N, P, K, S, Ca, Mg) and three micronutrients (Mn, Fe, Zn) were analysed in samples obtained at three different developmental stages: beginning of shoot elongation, anthesis, and ripening. At each harvest, plant samples were separated into different organs (green and senescent leaves, stem sections, ears, grains). According to analyses of tissue concentrations at the beginning of shoot elongation, the plants were sufficiently equipped with nutrients. Elevated ozone levels neither affected tissue concentrations nor shoot uptake of the nutrients. CO(2) and nitrogen treatments affected nutrient uptake, distribution and redistribution in a complex manner. CO(2) enrichment increased nitrogen-use efficiency and caused a lower demand for nitrogen in green tissues which was reflected in a decrease of critical nitrogen concentrations, lower leaf nitrogen concentrations and lower nitrogen pools in the leaves. Since grain nitrogen uptake during grain filling depended completely on redistribution from vegetative pools in green tissues, grain nitrogen concentrations fell considerably with severe implications for grain quality. Ca, S, Mg and Zn in green tissues were influenced by CO(2) enrichment in a similar manner to nitrogen. Phosphorus concentrations in green tissues, on the other hand, were not, or only slightly, affected by elevated CO(2). In stems, 'dilution' of all nutrients except manganese was observed, caused by the huge accumulation of water soluble carbohydrates, mainly fructans, in these tissues under CO(2) enrichment. Whole shoot uptake was either remarkably increased (K, Mn, P, Mg), nearly unaffected (N, S, Fe, Zn) or decreased (Ca) under CO(2) enrichment. Thus, nutrient cycling in plant-soil systems is expected to be altered under CO(2) enrichment.     

Interaction of temperature, humidity, driver preferences, and refrigerant type on air conditioning compressor usage

Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity. Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted.     

Interaction of Temperature,Humidity, Driver Preferences,and Refrigerant Type on Air Conditioning Compressor Usage

ABSTRACT

Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity.

Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted.     

Emission inventory of eight elements,Fe, Al,K, Mg,Mn, Na,Ca and Ti,in dust source region of East Asia

Based on calculation of the emission rate of the atmospheric mineral dust and the data of elemental contents in surface soils, this paper calculates the emission inventory of eight main elements of the atmospheric dust, Fe, Al, K, Mg, Mn, Na, Ca and Ti, in the dust source region of East Asia. As the dust sources in both Northern China and the Southern Mongolia are of three types and, in each of the six source type areas, surface soils are relatively uniform in soil types and soil texture, a simple method to calculate the emission of an element in one source type area is proposed by multiplying the total emission of the dust PM₁₀ and PM₅₀ in the source type area with the mean percentage content of the element in surface soils of the area. Comparison of our calculation of the total Fe emission in the source region of East Asia with the total Fe deposition to the North Pacific Ocean, measured and calculated by previous authors, shows very good agreement. This general method can also be used for the emission calculation of any other element.     

Exposure patterns of UV filters, fragrances, parabens, phthalates, organochlor pesticides, PBDEs, and PCBs in human milk: correlation of UV filters with use of cosmetics

In order to assess potential risks of exposure to environmental chemicals, more information on concomitant exposure to different chemicals is needed. We present data on chemicals in human milk of a cohort study (2004, 2005, 2006) of 54 mother/child pairs, where for the first time, cosmetic UV filters, synthetic musks, parabens and phthalate metabolites were analyzed in the same sample along with persistent organochlor pollutants (POPs), i.e., organochlor pesticides and metabolites, polybrominated diphenylethers and polychlorinated biphenyls (PCBs). The two groups of chemicals exhibited different exposure patterns. Six out of seven PCB congeners and a majority of pesticides were present in all milk samples, with significant correlations between certain PCB congener and pesticide levels, whereas the cosmetic-derived compounds, UV filters, parabens and synthetic musks, exhibited a more variable exposure pattern with inter-individual differences. UV filters were present in 85.2% of milk samples, in the range of PCB levels. Comparison with a questionnaire revealed a significant correlation between use of products containing UV filters and their presence in milk for two frequently used and detected UV filters, 4-methylbenzylidene camphor and octocrylene, and for the whole group of UV filters. Concentrations of PCBs and organochlor pesticides were within ranges seen in Western and Southern European countries. For several POPs, mean and/or maximum daily intake calculated from individual concentrations was above recent US EPA reference dose values. Our data emphasize the need for analyses of complex mixtures to obtain more information on inter-individual and temporal variability of human exposure to different types of chemicals.     

UV Fourier transform measurements of tropospheric O3, NO2, SO2, benzene, and toluene.

Using the differential optical absorption spectroscopy (DOAS) technique and a Fourier transform spectrometer, NO2, SO2, O3, benzene. and toluene were measured during three measurement campaigns held in Brussels in 1995, 1996, and 1997. The O3 concentrations could be explained as the results of the local photochemistry and the dynamical properties of the mixing layer. NO2 concentrations were anti-correlated to the O3 concentrations, as expected. SO2 also showed a pronounced dependence on car traffic. Average benzene and toluene concentrations were, respectively 1.7 ppb and between 4.4 and 6.6 pbb, but high values of toluene up to 98.8 ppb were observed. SO2 concentrations and to a lesser extent, those of NO2 and 03, were dependent on the wind direction. Ozone in Brussels has been found to be influenced by the meteorological conditions prevailing in central Europe. Comparisons with other measurements have shown that 03 and SO2 data are in general in good agreement, but our NO2 concentrations seem to be generally higher.