Acute toxicity and effects of 1-alkyl-3-methylimidazolium bromide ionic liquids on green algae.

In the present study, the acute toxicity of 1-Alkyl-3-methylimidazolium bromide ([Cnmim]Br) on the green algal Scenedesmus obliquus and Chlorella ellipsoidea was determined. The length of alkyl side chain of these imidazolium ionic liquids were C4, C6, C8, C10 and C12. The primary production of S. obliquus was also assessed after they were exposed to 0.01, 0.05, 0.10, 0.50 and 1.00 mg/L of [C10mim]Br for 96 h. The results showed that the acute toxicity of these ionic liquids was positively correlated with the alkyl chain length. Meanwhile, the concentration of the ionic liquid strongly influenced the primary production of algae. These results indicate that [Cnmim]Br with longer alkyl length have toxic effects on the green algae, and the risk to aquatic ecosystems by ionic liquid's leaking into the water body must be evaluated in the future.

Effects of the 1-alkyl-3-methylimidazolium bromide ionic liquids on the antioxidant defense system of Daphnia magna.

This study examined the antioxidant responses of Daphnia magna following exposure to different concentrations of the ionic liquid (IL) 1-octyl-3-methylimidazolium bromide and the 50% LC(50) concentrations of methylimidazolium bromide ILs with different alkyl-chain lengths. Activities of antioxidant defense enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase) and levels of the antioxidant glutathione and the lipid peroxidation by-product malondialdehyde were measured using traditional methods or commercial kits. The concentration and the alkyl-chain length of ILs were found to strongly influence the antioxidant system of D. magna following IL exposure, and exposure to higher IL concentrations and to ILs with longer alkyl chains generally increased the enzyme activities and biomarker levels examined. Therefore, the present study suggests that oxidative stress is involved in the mechanism of IL-induced toxicity in D. magna.

[Optimally control urban railway noise by sound propagation path].

In order to control railway noise pollution in urban areas, the residential district located near the Zhegan railway in Hangzhou urban was taken for example, and some controlling measures were proposed based on the investigation in railway noise impact as well as the planning of the district, the environmental scene and the project devises. The measures included setting man-made soil slopes, noise barriers and virescence. Combining some of them could be a typical noise reduction scheme. The professional software Cadna/A was used to predict the noise reduction results of every scheme. Results show that the maximal difference of noise reduction is 19.4 dB and the noise reduction effect of the second scheme is best. However, if only railway noise influence is considered, the first scheme is best. The research results can provide reference for residential districts planning and noise control near the railway in urban areas.

[Impact of low-frequencies noise on the ability of thinking and judgment].

Three typical low frequency noise samples which were collected from some associated facilities in urban residential areas and white noise which was produced by acoustic apparatus were selected to compare the competence of brainwork index (AYP) and error rate in noisy environment with those in quiet environment, using dosage exercise method. The result indicates that AYP is lower in noisy environment and the error rate is higher than that in quiet environment, and there are significant differences between them. The changes of most testees in groups that use three different low frequency noise samples respectively are more obvious than the group that uses white noise, and the AYP difference attains significant level. It indicates that low frequency components are the main frequency elements to affect the ability of thinking and judgment. By paired samples t-test and frequency spectrums analysis, the results show that the impact degree of air condition outdoor unit noise is highest, and noise samples which have a peak frequency between 50-300 Hz have a more negative impact on the ability of thinking and judgment than other environmental noise.

The developmental toxicity of 1-methyl-3-octylimidazolium bromide on Daphnia magna.

The developmental toxicity of 1-methyl-3-octylimidazolium bromide ([C(8)mim]Br) on Daphnia magna was investigated. The 24 and 48 h LC(50) values for [C(8)mim]Br in D. magna were 1.99 and 0.95 mg/L, respectively. A series of multigenerational toxicity tests were then used to explore [C(8)mim]Br effects in D. magna. [C(8)mim]Br significantly inhibited the body lengths of the F0 and F1 1st generations. After 21 days of exposure, [C(8)mim]Br lowered the reproductive ability of the F0 and F1 1st generations. In F1 3rd generation, 21 days of [C(8)mim]Br exposure prolonged the time to bear the first egg and the time to the first brood compared with the control, but the number of first-brood offspring and the number of broods produced by these animals were reduced. After the recovery period all the reproductive parameters returned to normal in F1 1st generation except for the number of broods. The dead neonates increased with prolonged exposure and increasing concentrations, and the dead neonates of the F1 3rd generation went far beyond that of the F1 1st and F0 generations. The intrinsic rate of natural increase (r) values of the three D. magna generations significantly decreased after exposure to higher concentrations of [C(8)mim]Br compared with control groups. Collectively, these results suggest that [C(8)mim]Br exerts a toxic effect on the development of D. magna. This study also highlights the importance of systematically evaluating the potential effects of aquatic ecosystems of ionic liquids that may be released into bodies of water.

Acute effects of 1-octyl-3-methylimidazolium bromide ionic liquid on the antioxidant enzyme system of mouse liver.

The effects of acute exposure of intraperitoneal injection of aqueous 1-octyl-3-methylimidazolium bromide on the antioxidant enzymes and lipid peroxidation of the treated mouse liver were investigated in the present paper. Thirty mice were treated with 17.9 (0.5 median lethal dose, LD(50)) and 35.7 mg/kg (1 LD(50)) of the ionic liquid or saline solution by intraperitoneal injection for 10h. Significant increase in hepatosomatic index and decrease in liver protein content were found in 1 LD(50) group. No statistically significant change was observed in the activity of superoxide dismutase in both treated groups compared to the control group. In the case of catalase activity, the decrease was recorded only at dose of 1 LD(50). As for the activity of glutathione peroxidase, increase in 0.5 LD(50) group while significant decrease at dose of 1 LD(50) was noted. There was an increase in the activity of glutathione-S-transferase in these two treated groups in comparison to the control. However, no effect on the level of lipid peroxidation was found in the treated groups. These results showed that the acute exposure of aqueous ionic liquid could cause damage to mouse, leading to antioxidant responses in livers of the treated mice.

Microcystins cause embryonic toxicity in mice.

Microcystins produced by freshwater cyanobacteria are potent hepatotoxins and can cause animal intoxications and human illnesses. In the present study, the effects of microcystins on the embryonic development of Kunming mice were determined using cell extracts of Microcystis aeruginosa from the Nanwan reservoir, China. Forty-eight pregnant mice were divided into four groups of 12 mice. Pregnant mice in three experimental groups were injected intraperitoneally with cell extracts at doses equivalent to 3, 6, or 12 microg microcystins/kg body weight daily from gestational days 6-15, while the mice in the control group were injected on the same schedule with sterilized saline. Mice were killed on the 18th day of gestation and embryonic and fetal developmental indexes checked. The fetal mice were also examined for anomalies of external, skeletal, and internal organs. The results demonstrated a significant decrease in body weight gain of pregnant mice in the 12 microg/kg dose group when compared to the control group (p<0.05). Differences in mean body weight, body length, and tail length of the fetuses were also found in these two groups (p<0.05). However, no significant difference in these characteristics was detected in the 6 or 3 microg/kg dose groups when compared to the control group (p>0.05). Four fetuses in the 6 microg/kg body dose group were found to have a curving tail. Additionally, petechial hemorrhage and hydropic degeneration were observed in the livers of fetuses in the 6 and 12 microg/kg experimental groups. These results suggested that microcystins had both maternal and embryonic toxicity in mice.

[Computer simulation model of propagation and impact of undergroud garage noise between buildings in urban residential region].

Aimed at certain types of building dispositions in urban residential region, the noise impacts of the underground garage is analyzed and calculated with the simulation model of random point sound source. The comparison between the predicted results and measured value of noise level shows that the predicted model presents an acceptable degree of accuracy. Adopting this model to predict noise impacts of the underground garage in designed and newly-built residential region will provide scientific basis for effective noise

[Prediction and influence factors of the ramp's noise of the entrance or exit of garages].

Some typical entrances/exits of the underground garages are chosen in urban residential areas. On the basis of the optimization of the positions of the noise sampling points and the groupings of the synchronous sampling points, by means of the acoustical analysis of the noise samples, the relation of the correlative factors, among the ramps' noise of the entrances or exits of the garages, the structure, grade, shape of the ramps, upgrade and downgrade, is studied. The prediction model of the ramp's noise influence of the entrance or exit of the garage is established through amending the noise influence of the entrance or exit of the even concrete road.

Subjective annoyance caused by indoor low-level and low frequency noise and control method.

The influence of low-level noise has not been widely noticed. This paper discovered that low-level and low frequency noise (A-weighted equivalent level Leq < 45 dB) causes higher probability of subjective annoyance. The fuzzy mathematic principle was applied to deal with the threshold level of subjective annoyance from noise in this study; there is preferable relationship between the indoor noise and noise annoyance at low frequency noise level. Study indicated at the same centered noise level, the change of annoyance probability is mainly caused by the change of the frequency spectrum characteristic of the indoor noise. Under low noise level environment, without change of the medium-low frequency noise, the slight increase of medium-high frequency noise level with the help of noise sheltering effect can significantly reduce the noise annoyance. This discovery brings a new resolution on how to improve the environmental quality of working or living places. A noise control model is given in this study according to the acoustic analysis.

A new approach of drawing airport noise contours on computer based on Surfer.

Noise contours are used to describe the extent of airport noise pollution and to plan land use around airports. The L(WECPN) (weighted equivalent continuous perceive noise level) recommended by ICAO(International Civil Aviation Organization) is adopted as airport noise rating parameter in this paper. With the help of various mathematical models in the software Surfer, noise contours can be drawn automatically by the completed program in Visual C++ Code. Corrections for thrust, velocity, atmospheric temperature, humidity and lateral ground attenuation are also considered in the new method, which can improve the efficiency of drawing contours. An example of its use for drawing noise contours of an airport in Zhejiang Province of China is proposed and the predictions and the measurements show agreements well.