Key role of plankton species and nutrients on biomagnification of PAHs in the micro-food chain: A case study in plateau reservoirs of Guizhou, China.

There is considerable inconsistency in results pertaining to the biomagnification of PAHs in aquatic systems. Zooplankton specifically play an important role controlling the fate and distribution of organic contaminants up the food chain, particularly in large plateau reservoirs. However, it remains largely unknown how secondary factors affect the magnification of organic compounds in zooplankton. The present study assessed plankton species and nutrients affecting the trophic transfer of PAHs through the micro-food chain in plateau reservoirs, Guizhou Province China. Results show soluble ∑PAHs range from 99.9 - 147.3 ng L-1, and concentrations of ∑PAHs in zooplankton range from 1003.2 - 22441.3, with a mean of 4460.7 ng g-1 dw. Trophic magnification factors (TMFs) > 1 show biomagnifications of PAHs from phytoplankton to zooplankton. The main mechanisms for trophic magnification > 1 are 1) small Copepoda, Cladocera and Rotifera are prey for larger N. schmackeri and P. tunguidus, and 2) the δ15N and TLs of zooplankton are increasing with the increasing nutrients TN, NO3- and CODMn. As a result, log PAHs concentrations in zooplankton are positively correlated with the trophic levels (TLs) of zooplankton, and log BAFs of the PAHs in zooplankton are increasing with increasing TLs and log Kow. Temperature further enhances TMFs and biomagnifications of PAHs as noted by temperature related reductions in δ15N. There are also available soluble PAHs in the water column which are assimilated with increasing phytoplankton biomass within the taxa groups, diatoms, dinoflagellates and chlorophytes. Notable TMFs of PAHs in zooplankton in Guizhou plateau reservoirs are not significantly affected by phytoplankton and zooplankton biomass dilutions. The present study demonstrates the important roles of species selection, nutrients and temperature in the environmental fate of PAHs in freshwaters.

Bioadsorption, bioaccumulation and biodegradation of antibiotics by algae and their association with algal physiological state and antibiotic physicochemical properties.

Bioadsorption, bioaccumulation and biodegradation processes in algae, play an important role in the biomagnification of antibiotics, or other organic pollutants, in aquatic food chains. In this study, the bioadsorption, bioaccumulation and biodegradation of norfloxacin [NFX], sulfamethazine [SMZ] and roxithromycin [RTM]) is investigated using a series of culture experiments. Chlorella vulgaris was exposed to these antibiotics with incubation periods of 24, 72, 120 and 168 h. Results show the bioadsorption concentration of antibiotics in extracellular matter increases with increasing alkaline phosphatase activity (AKP/ALP). The bioaccumulation concentrations of NFX, SMZ and RTM within cells significantly increase after early exposure, and subsequently decrease. There is a significant positive antibiotics correlation to superoxide dismutase (SOD), the photosynthetic electron transport rate (ETR) and maximum fluorescence after dark adaptation (Fv/Fm), while showing a negative correlation to malondialdehyde (MDA). The biodegradation percentages (Pb) of NFX, SMZ and RTM range from 39.3 - 97.2, 41.3 - 90.5, and 9.3 - 99.9, respectively, and significantly increase with increasing Fv/Fm, density and chlorophyll-a. The accumulation of antibiotics in extracellular and intracellular substances of C. vulgaris is affected by antibiotic biodegradation processes associated with cell physiological state. The results succinctly explain relationships between algal growth during antibiotics exposure and the bioadsorption and bioaccumulation of these antibiotics in cell walls and cell matter. The findings draw an insightful understanding of the accumulation of antibiotics in algae and provide a scientific basis for the better utilization of algae treatment technology in antibiotic contaminated wastewaters. Under low dose exposures, the biomagnification of antibiotics in algae is affected by bioadsorption, bioaccumulation and biodegradation.

The association between ambient temperature and sperm quality in Wuhan, China.

BACKGROUND: Few epidemiological investigations have focused on the influence of environmental temperature on human sperm quality. Here, we evaluated the potential association between ambient temperature and human sperm quality in Wuhan, China, and examined the interactive effect of particulate matter (PM2.5) and temperature. METHODS: 1780 males who had been living in Wuhan for no less than three months and received semen analysis at the Department of Reproductive Medicine in Renmin Hospital of Wuhan University between April 8, 2013 and June 30, 2015 were recruited. Daily mean meteorological data and air pollution data (PM2.5, O3 and NO2) in Wuhan between 2013 and 2015 were collected. A generalized linear model was used to explore the associations between ambient temperature and sperm quality (including sperm concentration, percentage of normal sperm morphology, and progressive motility) at 0-9, 10-14, 15-69, 70-90, and 0-90 days before semen examination, and the interaction between temperature and PM2.5. RESULTS: The associations between ambient temperature and sperm quality were an inverted U-shape at five exposure windows, except for a lag of 0-9 days for sperm concentration. A 1 °C increase in ambient temperature above the thresholds was associated with a 2.038 (1.292 ~ 2.783), 1.814 (1.217 ~ 2.411), 1.458 (1.138 ~ 1.777), 0.934(0.617 ~ 1.251) and 1.604 (1.258 ~ 1.951) decrease in the percentage of normal sperm morphology at lag 0-9, lag 10-14, lag 15-69, lag 70-90, and lag 0-90 days, respectively. The interaction p-values of PM2.5 and temperature were mostly less than 0.05 at five exposure windows. When ambient temperature exposure levels were above the thresholds, a 0.979 (0.659-1.299) and 3.559 (0.251 ~ 6.867) decrease in percentage of normal sperm morphology per 1 °C increase in temperature at lag 0-90 days was observed in the PM2.5 ≤ P50 group and PM2.5 > P50 group, respectively. CONCLUSIONS: Our results indicate that exposure to ambient temperature has a threshold effect on sperm quality, and PM2.5 enhances the effect of temperature on sperm quality when temperatures are above the threshold.

The Short-Term Effect of Ambient Temperature on Mortality in Wuhan, China: A Time-Series Study Using a Distributed Lag Non-Linear Model.

Less evidence concerning the association between ambient temperature and mortality is available in developing countries/regions, especially inland areas of China, and few previous studies have compared the predictive ability of different temperature indictors (minimum, mean, and maximum temperature) on mortality. We assessed the effects of temperature on daily mortality from 2003 to 2010 in Jiang'an District of Wuhan, the largest city in central China. Quasi-Poisson generalized linear models combined with both non-threshold and double-threshold distributed lag non-linear models (DLNM) were used to examine the associations between different temperature indictors and cause-specific mortality. We found a U-shaped relationship between temperature and mortality in Wuhan. Double-threshold DLNM with mean temperature performed best in predicting temperature-mortality relationship. Cold effect was delayed, whereas hot effect was acute, both of which lasted for several days. For cold effects over lag 0-21 days, a 1 °C decrease in mean temperature below the cold thresholds was associated with a 2.39% (95% CI: 1.71, 3.08) increase in non-accidental mortality, 3.65% (95% CI: 2.62, 4.69) increase in cardiovascular mortality, 3.87% (95% CI: 1.57, 6.22) increase in respiratory mortality, 3.13% (95% CI: 1.88, 4.38) increase in stroke mortality, and 21.57% (95% CI: 12.59, 31.26) increase in ischemic heart disease (IHD) mortality. For hot effects over lag 0-7 days, a 1 °C increase in mean temperature above the hot thresholds was associated with a 25.18% (95% CI: 18.74, 31.96) increase in non-accidental mortality, 34.10% (95% CI: 25.63, 43.16) increase in cardiovascular mortality, 24.27% (95% CI: 7.55, 43.59) increase in respiratory mortality, 59.1% (95% CI: 41.81, 78.5) increase in stroke mortality, and 17.00% (95% CI: 7.91, 26.87) increase in IHD mortality. This study suggested that both low and high temperature were associated with increased mortality in Wuhan, and that mean temperature had better predictive ability than minimum and maximum temperature in the association between temperature and mortality.

[Association between ambient air pollution and stroke mortality in Wuhan, China: A time-series analysis].

OBJECTIVE: Using time-series analyses to determine the association between ambient air pollution and stroke mortality in Jiang'an District of Wuhan, China from 2003 to 2010. METHODS: Data on daily stroke mortality for the period 2003 January 1 to 2010 December 31 was obtained from Jiang'an District Center for Disease Control and Prevention, Wuhan and data on relevant air pollution and meteorological factors from the local municipal environmental monitoring center and meteorology bureau of Wuhan, respectively. Application of a time-series analysis in generalized additive model was applied to evaluate the association between air pollution and stroke mortality. RESULTS: Annual average concentrations of PM10, SO(2) and NO(2) during the study period were (115.0 ± 60.0), (50.2 ± 33.7), and (57.6 ± 25.3) µg/m³ respectively. The total stroke death was 9 204, including 4 495 women, and 7 628 people aged over 65-years old. In single-pollutant model, a 10 µg/m³ increase in previous day (lag 1 d) ambient pollutants was associated with 0.67% (95% CI: 0.25%-1.10%) excess risk in stroke mortality for PM10, 0.87% (95% CI: 0.13%-1.63%) excess risk for SO(2) and 2.07% (95% CI: 1.08%-3.07%) excess risk for NO(2), respectively. When co-pollutants were involved into the models, only NO(2) remained strongly associated with stroke mortality (ß = 2.07, 95% CI: 1.08-3.07, P < 0.001). A 10 µg/m³, increase of NO(2) in lag 1 d was associated with 1.77% (95% CI: 0.54%-3.01%), 2.27% (95% CI: 0.98%-3.57%) and 2.00% (95% CI: 0.59%-3.43%) excess risk in stroke mortality, respectively, after adjusting for PM10, SO(2)th PM10 and SO(2) e-specific and gender-specific analyses showed that the association between ambient air pollution and stroke mortality was stronger in the elderly (≥ 65 years old) people and women. A 10 µg/m, increase of PM10, SO(2) NO(2) in lag 1 d was associated with excess stroke mortality of 0.97% (95% CI: 0.37%-1.57%), 1.73% (95% CI: 0.69%-2.78%) and 2.98% (95% CI: 1.59%-4.39%) for women, respectively and 0.94% (95% CI: 0.47%-1.42%), 1.06% (95% CI: 0.23%-1.90%) and 2.50% (95% CI: 1.40%-3.62%) for the elderly people (> 65 years old), respectively. CONCLUSION: PM10 and gaseous pollutants (SO(2), NO(2)) were significant risk factors for acute stroke death, and people aged over 65-years old and women were more susceptible to the effect of ambient pollutants on stroke mortality.