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Objective To study the pollution and source apportionment differences of different periods PM2.5 in the residential community of suburb in Tianjin City during heating and non-heating periods. Methods From 2015 to 2016, daytime and nighttime PM2.5 samples were collected at a community in the suburb of Tianjin. The mass concentration of PM2.5 samples and major chemical components in PM2.5, including metal elements, polycyclic aromatic hydrocarbons (PAHs) and inorganic water-soluble ions were monitored. Positive matrix factorization (PMF) model was used to apportion potential sources of metal elements, PAHs and inorganic water-soluble ions in daytime and nighttime PM2.5. Results In the heating period, the concentrations of some metal elements of suburban residential community were higher in the daytime than in the nighttime. In the non-heating period, the concentrations of some PAHs and inorganic water-soluble ions of suburban residential community were higher in the nighttime than in the daytime. Meanwhile, the concentrations of some metal elements were greater in the daytime than in the nighttime. When in heating period, the main source of PM2.5 in the suburban residential community was coal combustion during daytime and its source contribution rate was 50.1% while secondary aerosol and fuel combustion emissions of gasoline and diesel vehicles were main sources during nighttime and their source contribution rates were 41.0% and 35.9%. The principal source of daytime PM2.5 in the suburban residential community was indoor activity emissions during non-heating period, and secondary aerosol was main source during nighttime and their source contribution rates were 29.8% and 31.1%. Conclusions The pollution status of PM2.5 in residential communities of suburban is serious, and the source apportionment of day and night PM2.5 samples has different in different heating periods.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the effects of chronic lead exposure on mRNA and protein expression of ASIC1a, ASIC2a, ASIC2b in hippocampus of baby-rats.</p><p><b>METHODS</b>The Wistar pregnant rats were randomly divided into 3 groups fed with distilled water or lead contained water (0.2% and 1.0% lead acetate) respectively, 5 rats in each group. The lead-exposure ranged from the 0 day of pregnancy to the offspring weaned. Then the baby-rats were fed with lead water like their mothers and killed at postnatal day 8 or 50. Atomic absorption spectrometry was used to determine lead content in the brain. RT-PCR and Western blotting were used to observe mRNA and protein expression of ASIC1a, ASIC2a and ASIC2b in their hippocampus respectively.</p><p><b>RESULTS</b>The brain lead content of test groups was higher than that of the control group (P < 0.01), and the lead content of the postnatal day 50 was higher than that in postnatal day 8 (P < 0.01). Compared with the control group, ASIC1a mRNA expression of 1.0% lead exposure in the hippocampus was uptrend (P < 0.01), ASIC1a protein expression of each test group was downtrend (P < 0.05), while for ASIC2a and ASIC2b mRNA and protein, there was no significant differences observed (P > 0.05).</p><p><b>CONCLUSION</b>ASIC1a expression in hippocampus can be changed by chronic lead exposure.</p>
Subject(s)
Animals , Female , Pregnancy , Rats , Acid Sensing Ion Channels , Hippocampus , Metabolism , Lead , Toxicity , Nerve Tissue Proteins , Genetics , Metabolism , Prenatal Exposure Delayed Effects , Genetics , RNA, Messenger , Genetics , Rats, Wistar , Sodium Channels , Genetics , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To observe the effect of chronic lead contaminant on protein expression of protein kinase (PKC) and calmodulin (CaM) in hippocampus of baby-rats.</p><p><b>METHODS</b>The Wistar pregnant rats were randomly divided into 3 groups fed with distilled water and lead-contained water (0.2% and 1.0% lead acetate) respectively. The lead exposure period ranged from the 0 day of pregnancy to the offspring weaned. Then the baby-rats were fed with lead water the same as their mothers. Pups were killed at postnatal day 8 and 50 respectively. Atomic absorption spectrometry was used to determine lead content of rats' brain. Western-blotting was used to observe protein expression of PKC and CaM in hippocampus of baby-rats.</p><p><b>RESULTS</b>The brain lead content of test groups was much higher than that of the control group in the same growth period (P < 0.01). The content of brain lead in rats of postnatal day 50 was significantly higher than that of rats of postnatal day 8 (P < 0.01). Compared with control group, PKC and CaM protein expressions of chronic lead exposure baby-rats in the hippocampus were down trend (P < 0.05).</p><p><b>CONCLUSION</b>The decrease of PKC and CaM protein expression level in hippocampus might be one of the molecular mechanisms of lead induced impairment of learning and memory.</p>
Subject(s)
Animals , Female , Male , Pregnancy , Rats , Calmodulin , Metabolism , Hippocampus , Metabolism , Lead , Toxicity , Prenatal Exposure Delayed Effects , Protein Kinase C , Metabolism , Rats, WistarABSTRACT
Objective To establish a rapid method having great capability for enrichment and anti-interference, higher sensitivity and good precision for determination of trace silver in drinking water. Methods The conditions of determination such as the definition of peak potentials, the selection of auxiliary electrolytes, the selection of kind and amount of oxidants and anti-interference test were carried out by MP-1 potentiometer using glass-carbon electrode. Results The lowest detection limit, average recorery rate and average relative standard deviation were 0.004 ug/ml, 100.3% and 2.73% respectively. Conclusion This method was suitable for determination of trace silver in drinking water.