[Health risk assessment of typical metalloid and heavy metals in rural drinking water in Shaanxi Province in 2020].

OBJECTIVE: Evaluate the health risks of metalloid and heavy metals in rural drinking water in Shaanxi Province, and provide a scientific basis for ensuring the safety of drinking water for rural residents. METHODS: In 2020, the rural drinking water in Shaanxi Province were monitored, referring to the "Sanitary Standards for Drinking Water"(GB 5749-2006) for arsenic(As), cadmium(Cd), chromium(Cr~(6+)), lead(Pb), and mercury(Hg) in the water. To evaluate the concentration of five metalloid and heavy metals, the health risk assessment method recommended by United States Environmental Protection Agency was used to evaluate the health risks of adults in rural areas exposed to metalloid and heavy metals through drinking water. RESULTS: In 2020, a total of 6232 water samples were monitored. The concentrations of Cd, Pb and Hg in the water all met the standards, and the compliance rates of As and Cr~(6+) were 99.98% and 98.09%, respectively. The carcinogenic risk level of As was 3.53×10~(-5), and the non-carcinogenic health risk levels of the four heavy metals in descending order were Pb>Cr~(6+)>Cd>Hg, and the total risk level was 0.105. The concentration level of As and the distribution of health risk levels were all in northern Shaanxi>Guanzhong region>southern Shaanxi(P<0.05). The concentration level and health risk level distribution of As and Cr~(6+) were all groundwater>surface water(P<0.05), and the concentration level and health risk level distribution of Cd, Pb and Hg were all surface water>groundwater(P<0.05). CONCLUSION: There was a potential health risk of As exposure in rural drinking water in Shaanxi Province in 2020. The non-carcinogenic health risks of four heavy metals intake of Cd, Hg, Pb and Cr~(6+) through drinking water were still at an acceptable level. The control of arsenic pollution in drinking water should be further strengthened to ensure drinking water safety.

Riverside underwater noise pollution threaten porpoises and fish along the middle and lower reaches of the Yangtze River, China.

The Yangtze River exhibits a high biodiversity and plays an important role in global biodiversity conservation. As the world's busiest inland river in regard to shipping, little attention has been paid to underwater noise pollution. In 2017, the underwater noise level in 25 riverside locations along the middle and lower reaches of the Yangtze River mainly at night time were investigated by using passive acoustic monitoring method. Approximately 88% and 40% of the sampled sites exhibit noise levels exceeding the underwater acoustic thresholds of causing responsiveness and temporary threshold shift, respectively, in cetacean. Noise pollution may impose a high impact on fish with physostomous swim bladders and Weberian ossicles, such as silver carp, bighead carp, goldfish and common carp, whereas it may affect fish with physoclistous swim bladders and without Weberian ossicles, such as lake sturgeon and paddlefish, to a lesser extent. Noise levels reductions of approximately 10 and 20 dB were observed in the middle and lower reaches, respectively, of the Yangtze River over the 2012 level. The green development mode of the ongoing construction of green shipping in the Yangtze River Economic Belt, including the development of green shipping lanes, ports, ships and transportation organizations, may account for the alleviated underwater noise pollution. Follow-up noise mitigation endeavors, such as the extension of ship speed restrictions and the study and implementation of the optimal navigation speed in ecologically important areas, are required to further reduce the noise level in the Yangtze River to protect local porpoises and fish.

[Analysis of internal exposure levels of manganese, cobalt, selenium and molybdenum in blood and urine among general population in parts of Shaanxi Province].

OBJECTIVE: To investigate the internal exposure levels of manganese(Mn), cobalt(Co), selenium(Se) and molybdenum(Mo) in blood and urine among the general population in parts of Shaanxi Province, and thereby to analyze their population distribution characteristics. METHODS: In 2017, a total of 720 subjects of general people aged 3-79 years were recruited from 5 counties in Shaanxi Province, by stratified random sampling method, blood and urine samples were collected, and the contents of Mn, Co, Se and Mo in blood and urine samples were detected by inductively coupled plasma mass spectrometry(ICP-MS). The test result were statistically analyzed according to different genders, regions and age groups. RESULTS: Among general people in Shaanxi Province, the median of Mn in blood and urine were separately 8. 43 and 0. 60 µg/L. The median of Mn in blood among males and females were 7. 99 and 8. 81 µg/L, the difference was statistically significant(P<0. 05), the difference of blood Mn between urban and rural areas was statistically significant(P<0. 05). The median of Co in blood and urine were separately 0. 13 and 0. 17 µg/L, the median of Co in blood among males and females were 0. 12 and 0. 15 µg/L, the median of Co in urine among males and females were 0. 16 and 0. 20 µg/L, the differences were statistically significant(P<0. 05), the differences of blood Co and urine Co in urban and rural areas were statistically significant(P<0. 05). The median of Se concentration in blood and urine were separately 73. 20 and 13. 30 µg/L, the median of Se in urine among males and females were 14. 40 and 12. 40 µg/L, the difference were statistically significant(P<0. 05), the differences of blood Se and urine Se in urban and rural areas were statistically significant(P<0. 05). The median of Mo concentration in blood and urine were separately 0. 60 and 50. 40 µg/L, the median of Mo in urine among males and females were 56. 60 and 43. 00 µg/L, the difference was statistically significant(P<0. 05), the difference of blood Mo between urban and rural areas was statistically significant(P<0. 05). Within the same gender, all indexes in whole blood(except female blood Se) were statistically significant among age groups(P<0. 05). The differences of male urine Co, urine Se, urine Mo and female urine Co among age groups were statistically significant(P<0. 05). CONCLUSION: Among general population in Shaanxi Province, the Mn, Co, Se and Mo levels in blood and urine are varied by gender age and area, the blood Se level is relatively low.

[Analysis of polycyclic aromatic hydrocarbons pollution characteristics in PM_(2. 5) in two districts of Xi'an City from 2016 to 2018].

OBJECTIVE: To analyze the pollution characteristics of polycyclic aromatic hydrocarbons(PAHs) in atmospheric PM_(2. 5) in Lianhu district and Yanta district of Xi'an City. METHODS: From 2016-2018, PM_(2. 5) samples were regularly collected at monitoring points in two districts of Xi'an City, and analyzed the content of naphthalene, acenaphthylene, fluorene, acenaphthene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenz(a, h)anthracene, benzo(g, h, i)perylene, indeno(1, 2, 3-cd)pyrene in the samples according to Ambient air and stationary source emissions-Determination of gas and particle-phase polycyclic aromatic hydrocarbons-High performance liquid chromatography(HJ 647-2013). The test result were analyzed and evaluated according to different years, regions and seasons. RESULTS: The median total PAHs mass concentrations(ΣPAHs) in Lianhu district and Yanta district were 11. 68 and 12. 53 ng/m~3, respectively, with no significant difference(P>0. 05). The ΣPAHs of the two districts were decreasing year by year(P<0. 05). The median ΣPAHs in Lianhu district and Yanta district were highest in winter(55. 50, 55. 61 ng/m~3) and lowest in summer(4. 62, 4. 57 ng/m~3). The top three single indicators of the median PAHs in Lianhu district were benz(b)fluoranthene(1. 90 ng/m~3), benzo(g, h, i)perylene(1. 67 ng/m~3) and chrysene(1. 34 ng/m~3), In Yanta district, they were benz(b)fluoranthene(1. 95 ng/m~3), benzo(g, h, i)perylene(1. 63 ng/m~3) and pyrene(1. 47 ng/m~3). The average mass concentrations of benzo(a)pyrene in Lianhu district and Yanta district were 1. 33 ng/m~3 and 1. 10 ng/m~3, respectively. Among all the samples, the qualified samples of benzo(a)pyrene accounted for 72. 75% of the total samples, and the Lianhu district and Yanta district were 71. 20% and 74. 30%, respectively(P>0. 05). CONCLUSION: The degree of atmospheric PAHs pollution in Xi'an had decreased year by year, and PAHs pollution in winter was more serious.

[Pollution characteristics and source analysis of metal and metalloid elements in PM_(2. 5)in two districts of Xi'an City from 2016 to 2018].

OBJECTIVE: To investigate the concentration levels and sources of 12 metals and metalloids in PM_(2. 5) in Lianhu district and Yanta district of Xi'an City. METHODS: From 2016-2018, PM_(2. 5) samples were collected periodically in the monitoring points of the two urban areas of Xi'an City. According to the ministry of environmental protection's "Ambient air and stationary source emission-Determination of metals in ambient particulate matter-Inductively coupled plasma/mass spectrometry"(HJ 657-2013) to determine the content of 12 metals and metalloid elements(Sb, Al, As, Be, Cd, Cr, Hg, Pb, Mn, Ni, Se, Ti). To analyse and evaluate of As, Cd, Pb and Hg according to the annual average reference concentration limit of "Ambient air quality standards"(GB 3095-2012). The main sources of 12 metals and metalloid elements were identified by enrichment factor(EF) and factor analysis. RESULTS: The total qualified rates of As, Cd, Pb and Hg were 46. 89%, 83. 03%, 99. 00% and 100. 00%, respectively, and the difference between the years was not statistically significant(P>0. 05). The average concentration of 12 metals and metalloid elements in PM_(2. 5) for three years was as follows: Al>Pb>Mn>As>Se>Sb>Cr>Cd>Ti>Ni>Hg>Be. The average concentration of As was 10. 10 ng/m~3, which was 1. 68 times exceeding the standard. The average concentration of Cd was 2. 68 ng/m~3, and the average concentration of Pb was 81. 26 ng/m~3. Concentration levels of As, Cd and Pb were on the decline. The EF values of Al, Cr, and Ni were all ≤1, the EF value of As was between 1 and 10. The EF values of Sb, Pb and Ti were all >10, and the EF values of Cd and Se were all >300. The main components of each year from 2016 to 2018 were 2, 2 and 3 respectively. The main component 1 included Pb, As, Cd, Se, Sb and Mn, and the main component 2 included Al, Cr and Ni. In 2018, the main component 3 included Ti(Ti was located in the main component 1 in 2016 and 2017). CONCLUSION: The sources of pollution of metals and metalloid elements in PM_(2. 5) in the atmosphere of Xi'an City mainly include motor vehicle emissions, coal combustion, industrial pollution and natural particles.

Evoked-potential audiogram variability in a group of wild Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis).

Hearing is considered the primary sensory modality of cetaceans and enables their vital life functions. Information on the hearing sensitivity variability within a species obtained in a biologically relevant wild context is fundamental to evaluating potential noise impact and population-relevant management. Here, non-invasive auditory evoked-potential methods were adopted to describe the audiograms (11.2-152 kHz) of a group of four wild Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis) during a capture-and-release health assessment project in Poyang Lake, China. All audiograms presented a U shape, generally similar to those of other delphinids and phocoenids. The lowest auditory threshold (51-55 dB re 1 µPa) was identified at a test frequency of 76 kHz, which was higher than that observed in aquarium porpoises (54 kHz). The good hearing range (within 20 dB of the best hearing sensitivity) was from approximately 20 to 145 kHz, and the low- and high-frequency hearing cut-offs (threshold > 120 dB re l µPa) were 5.6 and 170 kHz, respectively. Compared with aquarium porpoises, wild porpoises have significantly better hearing sensitivity at 32 and 76 kHz and worse sensitivity at 54, 108 and 140 kHz. The audiograms of this group can provide a basis for better understanding the potential impact of anthropogenic noise.

[Variation characteristics and meteorological influencing factors of PM_(2. 5)mass concentration in Xi'an City from 2015 to 2018].

OBJECTIVE: To master the variation characteristics of PM_(2. 5) mass concentration in Lianhu district and Yanta district of Xi'an City and its relationship with meteorological conditions. METHODS: From 2015 to 2018, according to the environmental monitoring data of six main urban areas in Xi'an City in 2012, including NO_2, SO_2, PM_(10), PM_(2. 5), CO and O_3, air samples were collected in the relatively heavy polluted Lianhu district and the relatively light Yanta district of Xi'an City. The mass concentration test of PM_(2. 5) was carried out in accordance with the Ministry of Environmental Protection's "Determination of atmospheric articles PM_(10) and PM_(2. 5) in ambient air by gravimetric method "(HJ 618-2011). According to the Ambient air quality standards(GB 3095-2012), the average daily secondary concentration limit(75 µg/m~3) was used for statistical analysis and evaluation according to different annual, regional and seasonal test result. Meteorological data of Xi'an City were collected, including daily average temperature, daily average pressure, daily average relative humidity, daily average wind speed, daily precipitation, maximum temperature and minimum temperature, and the relationship between PM_(2. 5)concentration and meteorological factors was analyzed. RESULTS: A total of 660 air samples were collected and qualified, the median concentration of PM_(2. 5) was 71 µg/m~3. 356 air samples were qualified, and the pass rate was 53. 94%. The sample pass rate for each year from high to low was 2017>2018>2016>2015(P<0. 001), The average level of PM_(2. 5) mass concentration from high to low was 2015>2016>2017>2018(P<0. 001). There was no significant difference in the sample pass rate and PM_(2. 5)mass concentration between Lianhu district and Yanta district(P>0. 05). The qualified rate of samples from high to low in different seasons was summer>spring> autumn>winter(P<0. 05). The average concentration of PM_(2. 5) in different seasons from high to low was winter>autumn>spring>summer(P<0. 001). Mean temperature, mean air pressure, average wind speed, average relative humidity, precipitation and lowest temperature were significantly correlated with PM_(2. 5) mass concentration(P<0. 001). The determination coefficients of multiple regression analysis of meteorological factors in Lianhu and Yanta regions were 0. 390 and 0. 373, respectively. CONCLUSION: The air quality in Lianhu district and Yanta district of Xi'an City had improved year by year, and the pollution of PM_(2. 5) in autumn and winter was more serious. Meteorological conditions affected the concentration level of PM_(2. 5) in the atmosphere.

Underwater noise pollution in China's Yangtze River critically endangers Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis).

Underwater sound plays an important role in some critical life functions of many aquatic animals. Underwater noise pollution has received relatively more attention in ocean systems. However, little attention has been paid to freshwater systems, such as the Yangtze River which is the habitat of critically endangered Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis). In 2012, the underwater noise levels in 25 sites along the middle and lower sections of the Yangtze River were measured. The root mean square sound pressure level (SPL) and unweighted sound exposure level (SEL) at each site ranged between 105 ± 2.4 (median ± quartile deviation) and 150 ± 5.5 dB. Obvious spatial and temporal variations in the SPL were detected among the 25 sites. The SPL and SEL in the middle section of the Yangtze River were smaller (approximately 15 dB) and fluctuated more compared to those in the lower section. The power spectrum in the mainstem was site specific. However, all the spectra levels were higher than the audiogram of Yangtze finless porpoises. Majority of the sites had an averaged cumulative unweighted SEL (72%) and cumulative weighted SEL (68%) that surpassed the underwater acoustic thresholds for onset of hearing temporal threshold shifts for finless porpoise. Porpoise bio-sonars were detected in 89% of sonar monitoring sites indicating that noise pollution in the Yangtze River greatly threatened porpoise survival. In 8% of the sites, the averaged cumulative weighted SEL exceeded that of underwater acoustic thresholds causing non-recoverable permanent threshold shifts of finless porpoises auditory system whereas it was less than 1 dB below the underwater acoustic thresholds in other 8% of the sites. These sites urgently needed noise mitigation and management strategies. These results will facilitate the evaluation of the impacts of anthropogenic noise pollution on local finless porpoises and give further guidelines on its effective conservation.

Analysis of heavy metals in drinking water of rural schools in Shaanxi Province / 中国学校卫生

Objective@#To understand the status and trend of heavy metal indicators of drinking water in rural schools in different regions of Shaanxi Province, so as to provide scientific basis for safety of drinking water in rural schools.@*Methods@#In 2017-2019, 697 rural school water supply projects in Shaanxi Province were tested for heavy metal indicators in the peripheral water. According to the sanitary standard for drinking water (GB 5749—2006), five heavy metal indicators, including arsenic, cadmium, hexavalent chromium, lead and mercury, were analyzed and evaluated in different years and regions.@*Results@#A total of 2 298 valid water samples were collected and analyzed in 3 years. Except that lead and mercury are all up to standard, the standard rates of other heavy metals such as arsenic, cadmium and hexavalent chromium were 98.83%, 99.91% and 96.95% respectively. Compared with the Northern Shaanxi plateau and Qinba mountain area, the standard rate of water arsenic in Guanzhong Plain was lower (χ2=5.67, 13.59,P<0.01). The standard rate of hexavalent chromium was the highest in Qinba mountain area, followed by Guanzhong Plain, and the lowest in Northern Shaanxi plateau (χ2=20.48, 17.05, 48.32, P<0.01). Two samples of cadmium exceeding standard were from the Northern Shaanxi plateau.@*Conclusion@#The heavy metal index of drinking water in rural schools in Shaanxi Province exceeds the standard, which has obvious regional characteristics. We should focus on the harm of arsenic, hexavalent chromium and other heavy metals to the health of students in the Northern Shaanxi plateau and Guanzhong Plain. Cadmium and mercury in drinking water in local areas should be paid continued attention. Safety of drinking water in schools should be ensured from the aspects of water source selection and water treatment technology.

Drinking water current situation among Guanzhong area rural primary and secondary schools in 2018 / 中国学校卫生

Objective@#To investigate and analyze the drinking water quality among rural primary and secondary schools in Guanzhong area in 2018, and to provide a basis for the targeted improvement of water supply facilities.@*Methods@#Develop a questionnaire on the basic situation of centralized water supply in rural schools, according to the Standard Test Method for Drinking Water (GB/T 5750—2006) and the Sanitary Standard for Drinking Water (GB 5749—2006) for the rural school network in Guanzhong area. The peripheral water collection and testing carried out single factor and multifactor statistical analysis on the relationship between water quality influencing factors and water quality pass rate.@*Results@#The total qualified rate of drinking water quality in rural schools in Guanzhong area was 59.1%. Univariate analysis showed that water quality rate was affected by four factors including water source type, engineering type, sanitation permit and disinfection equipment use, and the difference was statistically significant(P<0.05). Unconditional two-class logistic regression analysis showed that disinfection (OR=3.14), engineering type (OR=2.05), and sanitation permit (OR=1.99)(P<0.05) affected the water quality pass rate.@*Conclusion@#It is recommended to further strengthen the investment in the renovation of water supply for rural schools in Guanzhong area, and specifically strengthen water supply treatment and standard disinfection.

[Analysis on monitoring results of toxicological indicators of rural drinking water in Shaanxi Province from 2016 to 2018].

OBJECTIVE: To understand the toxicological indexes of rural drinking water quality in 2016-2018 in Shaanxi Province. METHODS: From 2016 to2018, rural drinking water monitoring points were set up in all( 102) agriculture-related counties( districts) in Shaanxi Province. Each township selected 1-2 rural water supply systems for terminal water supply and terminal water and waste water for distributed water supply as monitoring points. A total of 18 284 monitoring points were set. Water samples were collected during the dry season from April to June and from July to September, according to the Standard Test Method for Drinking Water( GB/T 5750. 5-2006, GB/T5750. 6-2006, GB/T 5750. 8-2006). Carried out experimental analysis and collected water quality monitoring information through the "National Drinking Water Quality Monitoring Information System ". Experimental analysis according to the Standard Test Method for Drinking Water( GB/T 5750. 5-2006, GB/T 5750. 6-2006, GB/T5750. 8-2006); 11 toxicological indicators of the routine indicators were analyzed and evaluated according to the Standard of Drinking Water Hygiene( GB 5749-2006). RESULTS: From 2016 to 2018, the overall compliance rate of drinking water toxicology indicators in rural areas of Shaanxi Province was 81. 02%. The top four indicators exceeding the standard were fluoride( 9. 74%), nitrate nitrogen( 6. 09%) and hexavalent chromium. ( 4. 50%) and arsenic( 1. 44%), the other indicators exceeding the standard exceeds the range of 0. 01%-0. 32%. The difference of water quality compliance rates of cadmium, selenium, cyanide, fluoride and nitrate nitrogen in different years was statistically significant( P<0. 05), and the compliance rate of selenium, cyanide, fluoride and nitrate nitrogen increased with the year. Increasing trend( P<0. 05). The compliance rate of cadmium and selenium in the wet season was higher than that in the dry season, and the compliance rate of nitrate nitrogen in the dry season was higher than that in the wet season, the difference was statistically significant( P<0. 05). The compliance rate of arsenic, cadmium, hexavalent chromium, lead, selenium, fluoride and nitrate nitrogen in surface water were higher than that of groundwater( P < 0. 05). There was a statistically significant difference in the overall compliance rate of water toxicology between different water supply method in centralized water supply projects( P < 0. 001). The highest standard rate of water quality was observed in conventional water treatment, followed by sedimentation and filtration. There were 10, 10 and 4 types of over-standard indicators in Guanzhong, northern Shaanxi and southern Shaanxi, and the regional differences of 7 indicators including arsenic, cadmium, hexavalent chromium, lead, selenium, fluoride and nitrate nitrogen had statistics significance( P<0. 05). CONCLUSION: The overall compliance rate of toxicological indicators of drinking water in rural areas of Shaanxi Province is low, fluoride, nitrate nitrogen, hexavalent chromium and arsenic are serious and have obvious regional characteristics. In the future, we should focus on the excessive toxicological indicators, and ensure the safety and hygiene of drinking water from the aspects of water supply and treatment technology.

[Fluoride content in rural drinking water in Shaanxi Province during 2008-2018].

OBJECTIVE: To understand the fluoride index of drinking water quality and its trend in rural areas of Shaanxi Province since 2008, to evaluate the effect of water improvement on reducing fluoride. METHODS: In 2008-2018, rural drinking water monitoring points were set up in the jurisdiction of the agriculture-related counties( districts) in Shaanxi Province. Water samples were collected in the April-June dry seasons and July-September wet seasons, and tested according to the Standard Test Method for Drinking Water( GB/T 5750-2006). Collected and sorted water quality monitoring information through the National Drinking Water Quality Monitoring Information System, according to the Sanitary Standards for Drinking Water( GB 5749-2006), the comparison between groups and linear trend analysis were carried out according to different annual, water period, water source type, water supply mode and region. RESULTS: From 2008 to 2018, the overall compliance rate of fluoride in rural drinking water in Shaanxi Province was 93. 37%, the concentration of fluoride in water was in the range of0. 001-9. 880 mg/L, the median was 0. 370 mg/L, and the cumulative coverage of water quality fluoride exceeded the standard project was 3. 669 million. The difference of fluoride compliance rate in different years was statistically significant( χ~2= 120. 962, P<0. 001), and the fluoride compliance rate increased with the increase of the year( χ~2= 9. 241, P =0. 002), the fluoride compliance rate of surface water was higher than that of groundwater( χ~2= 1188. 563, P < 0. 001), there was a statistically significant difference in the compliance rate of fluoride in different water treatment processes in centralized water supply projects( χ~2= 2931. 231, P < 0. 001), the highest rate of fluoride in conventional treatment was 96. 63%( P < 0. 001), and the lowest disinfection rate was 84. 78%( P <0. 001). The distribution of drinking water sources in rural areas of Guanzhong and Northern Shaanxi was mainly groundwater, accounting for 88. 12% and 92. 25%, respectively, while Southern Shaanxi was dominated by surface water, accounting for69. 99%. There were significant differences in the fluoride compliance rates in Guanzhong region, Northern Shaanxi and Southern Shaanxi( χ~2= 1919. 335, P < 0. 001). Among them, the highest in Southern Shaanxi was 99. 84%( P < 0. 001), and the lowest in Northern Shaanxi was 89. 33%( P < 0. 001)( χ~2 SouthernShaanxi, Guanzhong= 1755. 724, χ~2 Southern Shaanxi, Northern Shaanxi= 2033. 8, χ~2 Northern Shaanxi, Guanzhong= 27. 535, P < 0. 001). The overall compliance rate of fluoride in water-reducing projects was 73. 80%, which cannot prove the trend of the overall compliance rate of fluoride in water-reducing projects with the year( χ~2= 3. 168, P = 0. 075). CONCLUSION: While achieving high result in the prevention and control of high fluorine water in Shaanxi Province, it is necessary to continue to implement effective measures to reduce fluorine content in rural drinking water, and to ensure the safety of drinking water from the aspects of water supply and treatment technology.

Soundscape of an Indo-Pacific humpback dolphin (Sousa chinensis) hotspot before windfarm construction in the Pearl River Estuary, China: Do dolphin engage in noise avoidance and passive eavesdropping behavior?

Soundscapes are vital to acoustically specialized animals. Using passive acoustic monitoring data, the temporal and spectral variations in the soundscape of a Chinese white dolphin hotspot were analyzed. By cluster analysis, the 1/3 octave band power spectrum can be grouped into three bands with median overall contribution rates of 35.24, 14.14 and 30.61%. Significant diel and tidal soundscape variations were observed with a generalized linear model. Temporal patterns and frequency ranges of middle frequency band sound matched well with those of fish vocalization, indicating that fish might serve as a signal source. Dolphin sounds were mainly detected in periods involving low levels of ambient sound and without fish vocalization, which could reflect noise avoidance and passive eavesdropping behaviors engaged in by the predator. Pre-construction data can be used to assess the effects of offshore windfarms on acoustic environments and aquatic animals by comparing them with the soundscape of postconstruction and/or postmitigation.

Drinking water and toilet sanitation of rural primary schools and middle schools in the northern，southern and central regions of Shaanxi during 2016-2018 / 中国学校卫生

Objective@#To understand the environmental sanitation situation of rural schools in different geographical areas of Shaanxi, and to provide scientific basis for improving hygiene and sanitation in Chinese rural schools.@*Methods@#Each year during 2016 to 2018, 150 townships in 30 counties of rural areas were randomly selected in various districts and cities throughout the province. In each township one junior high school and one elementary school were randomly selected, and the data was obtained through resource access, interviews, and on-site observations. The data was statistically analyzed and evaluated according to the northern, central and southern regions.@*Results@#The differences of drinking ways among students in the schools were of statistical significance(χ2=25.89,P<0.01). The major drinking water method of students in the monitoring schools of the three regions all was providing boiled water, accounting for 56.16%, 65.88%, 50.39%, all of which have direct drinking unboiled water phenomenon; The water supply method of the self-provided centralized water supply school is mainly precipitation filtration in the central and southern regions, accounting for 38.46%, 53.21%, and untreated in the northern region(60.61%); The differences of the proportions of having sanitary toilets, detached toilets in schools, having toilets in teaching buildings, and having toilets in dormitory buildings in three regions were of statistical significance(χ2=32.04, 12.73, 20.78, 33.11, P<0.01) The proportion of schools with squat toilets in men’s toilets was greater than that of women’s(χ2=86.53, 44.77, 21.88, P<0.01). The differences of the proportion of schools with faucets available in toilets and within 5 meters around toilets, with sinks in or around the toilets, with sinks equipped with soap in or around the toilets were of statistical significance(χ2=90.02, 10.40, 41.96, P<0.01).@*Conclusion@#During 2016 to 2018, the environment sanitation of the three major rural primary and middle schools in Shaanxi Province needs to improve corresponding supporting facilities, and increase publicity to improve teachers and students’ awareness of health and safety.

Microbial contamination of drinking water in rural schools in Shaanxi in 2018 / 中国学校卫生

Objective@#To understand the disinfection status and microbial pollution of water supply project in rural schools in Shaanxi Province in 2018, and to provide basis for improving drinking water quality in rural schools.@*Methods@#Data of water quality of water supply project in rural schools of Shaanxi Province in 2018 was collected, and the disinfectant surplus and microbial index compliance rate were analyzed according to "Sanitary Standard for Drinking Water" (GB 5749-2006).@*Results@#The overall compliance rate of microbial indicators of water supply projects in rural schools in Shaanxi Province was 68.09%, and that of groundwater microbial indicators(71.97%) was higher than that of surface water(61.42%)(χ2=15.68, P<0.01); The overall compliance rate of microbial indicators in flood season(71.85%) was higher than that in dry season(64.34%)(χ2=7.44, P<0.01); The rate of reaching the standard of disinfectant residue was 77.27%. The rate of reaching the standard of microbial index of water samples with disinfection measures was higher than that of water samples without disinfection measures (χ2=31.88, P<0.01), The rate of reaching the standard of microbial index of water samples with disinfectant residue(88.89%) was higher than that of water samples with disinfectant residue(44.44%)(χ2=12.28, P<0. 01).@*Conclusion@#The main cause of microbial contamination of drinking water in rural schools in Shaanxi Province is inadequate equipment of disinfection equipment in water supply projects or not being used as required. It is suggested that schools, education and health departments should take measures to strengthen supervision and management of water plants to ensure the normal use of disinfection equipment.

Sodium sulfite promotes the assembly and secretion of very low-density lipoprotein in HL-7702 hepatocytes.

This study investigated the effects of Na2SO3 on the fat metabolism in human normal diploid HL-7702 (referred as L-02) hepatocytes. After 24 h and 48 h, treatment with different concentrations of Na2SO3, the intra and extra-hepatocellular triglyceride (TG) contents of L-02 were determined using chemical-enzymatic method. The contents of very low-density lipoprotein (VLDL) and apolipoprotein B100 (apoB100) in the culture supernatants were determined using enzyme-linked immunosorbent assay (ELISA). Western blot was applied to detect the expressions of fatty acid oxidation and fat synthesis related proteins, VLDL assembly and secretion in L-02 cells. RESULTS: Na2SO3 treatment (10 mM, 24 h/48 h) significantly increased the intra TG level in the hepatocytes. Different concentrations of Na2SO3 increased the extra-hepatocellular TG content. After 24 h exposure, the extracellular VLDL levels and secretions of apoB100 in 0.1-10 mM Na2SO3 groups were significantly higher than that of the negative control (P < 0.05). Meanwhile, the expression of CPT1 and SREBP1 protein were significantly reduced by Na2SO3. MTP and TGH protein expressions were significantly elevated in each Na2SO3 treatment group. The expression level of LDLR in hepatocytes was reduced by Na2SO3. CONCLUSION: Na2SO3 exposure may promote the hepatocellular VLDL assembly and secretion, through increasing of MTP and TGH expressions and inhibiting the uptake of extracelluar VLDL.

Sulfite exposure-induced hepatocyte death is not associated with alterations in p53 protein expression.

Although sulfite (SO3(2-)) is commonly used as an antimicrobial agent and preservative in foods, medicines and wine, it has also been listed as an important risk factor for the initiation and progression of liver diseases due to oxidative damage. In general, apoptosis that is induced by oxidative stress is triggered by increases in p53 and alterations in Mdm2 and Bcl-2. However, the level of involvement of the p53 signaling pathway, which has been shown to be upregulated in some animal studies, in hepatocyte death remains unclear. To examine the response of the p53 signaling pathway to stimulation with different concentrations of sulfite, a time course study of p53, Mdm2, and Bcl-2 expression was conducted in an immortalized hepatic cell line, HL-7702. When the HL-7702 cells were cultured in the presence of Na2SO3, the cell viability was significantly decreased after 24h compared to that of the control group (0mmol/L) (p<0.05). Meanwhile, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the supernatants of HL-7702 cells were significantly increased following Na2SO3 administration. Interestingly, the expression of p53 and p-p53 (Ser15) remained unchanged. In addition, no obvious alterations in Mdm2 and Bcl-2 expression were observed in HL-7702 cells that had been stimulated with various concentrations of sulfite. To further investigate the detailed mechanism underlying sulfite toxicity, caspase-3, PCNA and RIP1 expression in HL-7702 cells was studied. The expression levels of caspase-3 and PCNA were unchanged, but RIP1 expression was increased significantly after 24h of exposure. In light of this evidence, we propose that sulfite is cytotoxic to hepatocytes, but this cytotoxicity is not achieved by direct interruption of the p53 signaling pathway. In addition, we propose that an alternative necrotic process underlies hepatocellular death following sulfite exposure.