Challenges and engineering application of landfill leachate concentrate treatment.

Landfill leachate concentrate (LLC) is a concentrated waste stream from landfill leachate treatment systems and has been recognized as a key challenge due to its high concentration of salts, heavy metals, organic matters, etc. Improper management of LLC (e.g. reinjection) would exacerbate the performance of upstream treatment processes and pose risks to the surrounding environments near landfill sites. Addressing the challenge and recovering resources from LLC have thus been attracting considerable attention. Although many LLC treatment technologies have been developed, a comprehensive discussion about the challenges still lacks. This review critically evaluates mainstream LLC treatment technologies, namely incineration, coagulation, advanced oxidation, evaporation and solidification/stabilization. We then introduce a geopolymer-based solidification (GS) process as a promising technology owning to its simple casting process and reusable final product and summarize engineering applications in China. Finally, we suggest investigating hybrid systems to minimize LLC production and achieve the on-site reuse of LLC. Collectively, this review provides useful information to guide the selection of LLC treatment technologies and suggests a sustainable alternative for large-scale application, while also highlighting the need of joint efforts in the industry to achieve efficient, ecofriendly and economical on-site management of landfill waste streams.

Association between season of conception, month of conception with preterm birth in China: a population-based retrospective cohort study.

BACKGROUND: Seasonal patterns of preterm birth were identified in previous studies, but the effect of conception season on preterm birth has not been extensively studied. Based on the notion that the etiological roots of preterm birth lie in the beginning of pregnancy, we did a population-based retrospective cohort study in Southwest China to examine the effects of season of conception and month of conception on preterm birth. METHODS: We did a population-based retrospective cohort study in women (aged 18-49) who participated in the NFPHEP from 2010 to 2018, and had a singleton livebirth in southwest China. According to the time of the last menstruation reported by the participants, month of conception and season of conception were then ascertained. We used multivariate log-binomial model to adjust the potential risk factors for preterm birth and obtained adjusted risk ratio (aRR) and 95% confidence intervals (95%CI) for conception season, conception month and preterm birth. RESULTS: Among 194 028 participants, 15 034 women had preterm birth. Compared with pregnancies that were conceived in the summer, pregnancies that were conceived in the spring, autumn and winter had the higher risk of preterm birth (Spring: aRR = 1.10, 95% CI: 1.04-1.15; Autumn: aRR = 1.14, 95% CI: 1.09-1.20; Winter: aRR = 1.28, 95% CI: 1.22-1.34) and also had a higher risk of early preterm birth (Spring: aRR = 1.09, 95% CI: 1.01-1.18; Autumn: aRR = 1.09, 95% CI: 1.01-1.19; Winter: aRR = 1.16, 95% CI: 1.08-1.25). Pregnancies in December, and January had a higher risk of preterm birth and early preterm birth than pregnancies that were conceived in July. CONCLUSIONS: Our study found that preterm birth was significantly related to season of conception. Preterm and early preterm birth rates were the highest among pregnancies that were conceived in winter, and the lowest among pregnancies in summer.

The association between periconceptional folic acid supplementation and the risk of preterm birth: a population-based retrospective cohort study of 200,000 women in China.

PURPOSE: The aim of this study was to examine the association between periconceptional folic acid (FA) supplementation and risk of preterm birth. METHODS: We conducted a retrospective cohort study in women aged 18-49 who participated in the NFPHEP from 2010 to 2018, and had a singleton livebirth in 129 counties in southwest China. Participants were divided into four groups according to the time period starting FA use: no use, after the last menstrual period, at least 1-2 months before the last menstrual period, at least 3 months before the last menstrual period. The outcomes were preterm birth (gestation < 37 weeks) and early preterm birth (gestation < 34 weeks). RESULTS: 201,477 women were included and 191,809 (95.2%) had taken FA during periconception. Compared with women who did not take FA, women who started taking FA 1-2 months before their last menstrual period had a 15% lower risk of preterm birth (aOR = 0.85, 95% CI 0.79-0.92), and women who started taking FA at least 3 months before their last menstrual period had a 20% lower risk of preterm birth (aOR = 0.80, 95% CI 0.75-0.87), but women who started taking FA after their last menstrual period did not appear to reduce the risk of preterm birth. CONCLUSIONS: In this study of 200,000 Chinese women, periconceptional supplementation with FA was associated with a lower risk of preterm birth. Women who started taking FA at least 3 months before their last menstrual period were more likely to reduce the risk of preterm birth.

N-Rich Carbon Catalysts with Economic Feasibility for the Selective Oxidation of Hydrogen Sulfide to Sulfur.

The efficient removal of hydrogen sulfide (H2S) from exhaust emissions is a great challenge to chemical industries. Selective catalytic oxidation of H2S into elemental sulfur is regarded as one of the most promising approaches to alleviate environmental pollution, while recycling sulfur resources. It is therefore highly desirable to develop efficient catalysts for the conversion of H2S to sulfur under mild reaction conditions. Here we present a nitrogen-rich carbon obtained by the direct thermal treatment of commercial polyaniline (PANI) for the selective oxidation of H2S in a continuous way at relatively low temperature (180 °C). The efficient conversion of H2S over the N-rich carbon catalysts was attributed to the in situ generation of pyridine-N on the carbon matrix, which served as the active sites to promote the absorption and dissociation of H2S molecules, achieving a superior catalytic conversion rate of 99% and selectivity up to 95% at 180 °C.

Prevalence of anemia and sociodemographic characteristics among pregnant and non-pregnant women in southwest China: a longitudinal observational study.

BACKGROUND: Globally, the prevalence of anemia among women of reproductive age is about 29.4%, and anemia impacts about 40% of pregnant women and more than 20% of non-pregnant women. We conducted a longitudinal observational study of anemia in pregnant and non-pregnant women, and analyzed the association between the prevalence of anemia and sociodemographic characteristics of women in southwest China. METHODS: This study was a longitudinal observational study which involved 640,672 women aged 18-49 years from 129 counties in southwest China. Data were from databases of National Free Preconception Health Examination Project (NFPHEP) and electronic medical records of local hospitals. We adjusted the diagnostic thresholds of anemia for altitude. The prevalence of anemia was expressed in percentages and 95% confidence intervals (95% CI). The association between the prevalence of anemia and sociodemographic characteristics of pregnant and non-pregnant women were analyzed using univariate and multivariate logistic regression method, expressed in crude odds ratio (cOR), adjusted odds ratio (aOR) and 95%CI. RESULTS: Of the 640,672 participants, 121,254 women suffered from anemia, with the prevalence of 18.9% (95%CI: 18.8-19.0%). From 2014 to 2018, the prevalence of anemia declines from 23.0-16.4%.The prevalence was 21.6% in the first trimester, higher than women in non-pregnancy (17.4%) and women in the third trimester (10.5%). Results from the multivariable logistic regression showed that women aged 18-20 (aOR = 1.28) or over 35 years old (aOR = 1.07), being farmers (aOR = 1.42), being ethnic minorities (aOR: 1.19 ~ 1.73), during the first trimester (aOR = 1.32) were more likely to be anemic. CONCLUSIONS: Although the anemia prevalence of women of reproductive age has been decreasing in recent years, the prevalence of anemia is still high in pregnant and non-pregnant women in southwest China, especially during the first trimester. Women who were older or younger, being farmers, being ethnic minorities were at high risk of anemia. Anemia in women of reproductive age cannot be neglected.

[Status assessment of preconception health risk exposure in Chinese reproductive women during 2010-2012].

OBJECTIVE: To assess the exposure status of preconception health risk of Chinese reproductive women and analyze the changes of their exposure status during 2010-2012. METHODS: The "Core Indicators of Preconception Health Risk Exposure Status in Chinese reproductive couples" were used to evaluate the preconception health risk of women during reproductive period (aged 21-49 years) who participated in National Free Preconception Health Examination Project. From January 1, 2010 to December 31 2012 a total of 2 120 131 women were recruited from 220 pilot counties of 31 provinces. The risks involved the following eight aspects: genetic risk, reproductive risk, chronic disease risk, infectious risk, nutritive risk, behavioral risk, environmental risk and psychosocial risk. RESULTS: The overall rate of preconception health risk in Chinese reproductive women (aged 21-49 years) was 54.63% (1 124 552/2 058 648). Among all age groups, the lowest rate was 53.05% (262 646/495 092) in 21-24 age group while the highest rate 66.94% (7616/11379) in 45-49 age group. The top three risks were nutritive risk [35.74% (726 826/2 033 730)], infectious risk [10.16% (206 983/2 037 022)] and chronic disease risk [6.96% (142 130/2 042 110)]. From 2010 to 2012, the rate of preconception health risk in Chinese reproductive women (aged 21-49) were 55.35% (182 087/328 991) (2010), 56.03% (502 888/897 511) (2011) and 52.82% (439 577/832 146) (2012) respectively. In different years, the rates of nutritive, infectious, behavioral and genetic risks were all highest in 2011. And the rates of eight types of risks were all lowest in 2012. In different age groups, all eight risks were lowest in 21-24 age group and highest in 45-49 age group. And the preconception health risk increased with age. CONCLUSION: The general status of preconception health of reproductive women is fair. However, there are still some risks. The preconception health risk in Chinese reproductive women showed a declining trend during 2010-2012.

[Status assessment of preconception health risk exposure among 2 030 083 males in 31 provinces during 2010-2012].

OBJECTIVE: To assess the exposure status of preconception health risk of Chinese males aged 21-49 years in 31 provinces and analyze the changes of their exposure status during 2010-2012. METHODS: The "Core Indicators of Preconception Health Risk Exposure Status in Chinese reproductive couples" were used to evaluate the preconception health risk of males aged 21-49 years who participated in National Free Preconception Health Examination Project. From January 1, 2010 to December 31, 2012, a total of 2 030 083 males were recruited from 220 pilot counties of 31 provinces. The risks involved three aspects closely correlated with offspring health: behavioral risk, infectious risk and genetic risk. RESULTS: The overall smoking rate of Chinese rural males aged 21-49 years was 31.19% (622 837/1 997 051). They smoked a daily average of 10 cigarettes. The median number of cigarettes smoked was 10 per day and it increased with age. The overall drinking rate was 31.81% (634 556/1 994 925). Meanwhile, median alcohol consumption increased with age. The rate of males with a history of birth defect, family inbreeding and familial genetic disease accounted for 0.12% (2 344/1 994 324), 0.20% (4 043/1 997 707) and 0.94% (18 736/2 000 005) respectively. The rates of males with a history of hepatitis B and sexually transmitted diseases were 0.67% (13 317/1 988 904) and 0.05% (912/1 988 904) respectively. HBsAg positive rate was 6.32% (124 274/1 965 821). And the positive screening rate of Treponema pallidum was 0.37% (7 169/1 947 021). Among three types of risks, the highest risk was behavioral risk while the lowest risk genetic risk. Behavioral risk, genetic risk and sexually transmitted diseases in infectious risk were all lowest in 2012 while HBV infection in infectious risk was lowest in 2010. CONCLUSION: The general status of preconception health is fair for rural males aged 21-49 years in 31 provinces. However, there are still some behavior, genetic and infectious risks. The preconception health risk of rural males showed an overall declining trend during 2010-2012.

[Evaluation and trend analysis of prepregnancy nutrition in Chinese women of reproductive age during 2010-2012].

OBJECTIVE: To evaluate the prepregnancy nutritional status and analyze its trend in Chinese women of reproductive age during the period of 2010-2012. METHODS: Analyses of prepregnancy nutritional indicators were conducted for a total of 2 120 131women of reproductive age (aged 21-49 years) from 220 pilot counties of 31 provinces who participated in National Free Prepregnancy Health Examination Project from January 1, 2010 to December 31, 2012. The nutritional indicators involving body mass index (BMI), hemoglobin (HB) concentration and fasting plasma glucose (FBG) were statistically analyzed with SPSS 17.0 software. RESULTS: There were a sustained increase in prepregnancy HB concentration and declined levels of prepregnancy BMI and FBG during 2010-2012. The clinical data were categorized into 4 subgroups. The data of age composition showed the age group of 25-34 years was the largest proportion of the cohort. The prevalence in prepregnancy low-BMI population subgroup increased from 10.4% in 2010 to 14.14% in 2012. The prepregnancy obesity and overweight subgroups revealed the lowest prevalences of 10.65% and 2.32% respectively in 2012. A decreased prevalence of prepregnancy low FBG subgroup occurred from 5.45% in 2010 to 5.23% in 2012. The prevalences of prepregnancy impaired fasting plasma glucose and diabetes subgroups decreased year-on-year from 3.17% and 1.64% in 2010 to 2.71% and 1.05% in 2012 respectively. The prevalences of prepregnancy mild and severe anemia subgroups decreased from 12.29% and 0.95% to 9.62% and 0.78% respectively during the period 2010-2012. High hemoglobin concentration subgroup also exhibited a decreasing prevalence. Statistical analysis indicated significant differences (P < 0.001) in the evaluation and trend analysis of prepregnancy nutrition in Chinese women of reproductive age. CONCLUSION: Chinese women of reproductive age show a fair status of prepregnancy nutrition. And there are decreasing prevalences in obesity, anemia and diabetes.

Effects of ambient temperature and relative humidity on preterm birth during early pregnancy and before parturition in China from 2010 to 2018: a population-based large-sample cohort study.

Background: The progression of global warming and increase in instances of extreme weather have received considerable attention. We conducted a cohort study on women of childbearing age in Yunnan Province, examined the association between ambient temperature and humidity on preterm birth and evaluated the effects of extreme weather during early pregnancy and before parturition on preterm birth. Methods: We conducted a population-based cohort study on women of childbearing age 18-49 years who participated in National Free Preconception Health Examination Project (NFPHEP) in Yunnan Province from January 1, 2010, to December 31, 2018. Meteorological data, namely daily average temperature (°C) and daily average relative humidity (%), were obtained from China National Meteorological Information Center. Four exposure windows were explored: 1 week of pregnancy, 4 weeks of pregnancy, 4 weeks before delivery, and 1 week before delivery. We used a Cox proportional hazards model and adjusted the potential risk factors for preterm birth to obtain the effects of exposure to temperature and humidity on preterm birth among the stages of pregnancy. Results: At 1 week of pregnancy and at 4 weeks of pregnancy, the association between temperature and preterm birth was U-shaped. The correlation between relative humidity and the risk of preterm birth was n-type at 1 week of pregnancy. The correlation between preterm birth and temperature and relative humidity at 4 weeks before delivery and at 1 week before delivery is J-shaped. Low temperature and low humidity were protective factors against preterm birth, whereas high temperature and high humidity were risk factors for preterm birth.The effects of high temperature and extremely high temperature were the strongest at 4 weeks before delivery, with HRs of 1.417 (95% CI: 1.362-1.474) and 1.627 (95% CI: 1.537-1.722), respectively. The effects of extremely low humidity and low humidity were strongest at 1 week before delivery, with HRs of 0.681 (95% CI: 0.609-0.761) and 0.696 (95% CI: 0.627-0.771), respectively. Conclusion: Temperature and relative humidity affect preterm birth differently for each pregnancy stage. The effects of meteorological factors on pregnancy outcomes such as premature birth should not be ignored.

Ethnic differences in preterm birth in Southwest China, 2014-2018: A population-based observational study.

Objective: Preterm birth is a major healthcare problem and has been rising gradually in the past three decades in China. Yet the ethnic differences in the rates and distributions of preterm birth remain largely unknown in China. This study used data from Yunnan, a multiethnic province, to explore the differences in preterm birth across ethnicities. Methods: A population-based observational study was conducted based on data from the National Free Preconception Health Examination Project in rural Yunnan from Jan 1, 2014 to Dec 31, 2018. Pregnancies with at least one livebirth were included in this study. We estimated the rates and 95% confidence intervals (CIs) of overall preterm birth (born < 37 weeks' gestation), moderate to late preterm birth (born between 32 and <37 weeks' gestation), very preterm birth (born between 28 and 31 weeks' gestation), and extremely preterm birth (born < 28 weeks' gestation) across maternal ethnicity and compared them using log-binomial regressions. Multivariable log-binomial regressions were used to assess the association between maternal ethnicity and preterm birth with adjustment for potential confounders, including year of delivery, maternal age at delivery, education, occupation, pre-pregnancy body mass index, history of chronic disease, history of preterm birth, smoking and drinking alcohol during early pregnancy, and parity and multiple pregnancy of current pregnancy. Results: Among 195,325 women who delivered at least one live baby, 7.90% (95% CI, 7.78-8.02%) were born preterm. The rates of moderate to late preterm birth, very preterm birth, and extremely preterm birth were 6.20% (95% CI, 6.09-6.30%), 1.18% (95% CI, 1.13-1.23%), and 0.52% (95% CI, 0.49-0.56%), respectively. The rates of overall preterm birth, moderate to late preterm birth, very preterm birth, and extremely preterm birth differed across maternal ethnicity. The preterm birth rates in Dai (10.73%), Miao (13.23%), Lisu (12.64%), Zhuang (11.77%), Wa (10.52%), and Lagu (12.34%) women were significantly higher than that in Han women, and the adjusted relative risks were 1.45 [95% CI, 1.36, 1.54], 1.74 (95% CI, 1.62, 1.86), 1.60 (95% CI, 1.47, 1.75), 1.60 (95% CI, 1.46, 1.75), 1.40 (95% CI, 1.22, 1.60), and 1.67 (95% CI, 1.50, 1.87) respectively. There was no difference in preterm birth rate between Han women and Hani, Bai, or Hui women. Conclusion: This study found notable differences in the rates of preterm birth and its sub-categories across maternal ethnicities, which were especially higher in ethnic minority women. The findings suggest that greater efforts to reduce ethnic inequalities in preterm birth. Future studies are warranted to understand the drivers of ethnic inequalities in preterm birth in China.

Ethnic Disparities in Hepatitis B Virus Infection Among 1 Million Reproductive-Age Couples Preparing for Pregnancy in the Rural Yunnan, China: A Population-Based Cross-Sectional Study.

INTRODUCTION: Hepatitis B is a potentially life-threatening liver infection caused by hepatitis B virus (HBV) and China has the largest disease burden. We aim to understand the ethnic disparities in HBV infection among the married reproductive-age couples planning for pregnancy in Yunnan, a multiethnic province in Southwest China, to increase the health equities within the hepatitis response in China. METHODS: A population-based cross-sectional study was performed. Couples aged 20-49 years in rural Yunnan were enrolled through the National Free Preconception Health Examination Project from Jan 2014 to Dec 2019. HBsAg-positive couples were defined as couples in which one or both were HBsAg-positive, and HBsAg- and HBeAg-positive couples were defined as couples in which one or both were HBsAg- and HBeAg-positive. The HBV prevalence of positive couples was estimated by ethnicity. Multivariate logistic regression analyses were used to assess the association between ethnicity and HBsAg status. RESULTS: Overall, 63,513 of 1,060,643 couples (5.99%, 95% CI, 5.94%-6.03%) were HBsAg-positive, and 15,898 of 63,513 HBsAg-positive couples (25.03%, 95% CI 24.69%-25.37%) were HBsAg- and HBeAg-positive couples in rural Yunnan. The highest prevalence of HBsAg-positive couples was in the Miao and Miao ethnicity (12.04%) and Zhuang and Zhuang ethnicity (9.76%), and the risk of HBV infection of wives/husbands in these ethnic groups was significantly higher than that in the Han and Han ethnicity. Additionally, the HBsAg prevalence in wives/husbands has increased with the positive status of HBsAg and HBeAg of their spouses. CONCLUSION: The HBV prevalence in reproductive-age couples was intermediate (6% of 1 million couples) in rural Yunnan, China, with the highest in the Miao and Zhuang ethnicities. There are still large ethnic disparities in HBV infection in China. Therefore, China should make great efforts, especially giving priority to ethnic minorities and taking positive couples as an important unit of care, to equitably eliminate the HBV intrafamilial transmission.

Di2-ethylhexyl phthalate disrupts thyroid hormone homeostasis through activating the Ras/Akt/TRHr pathway and inducing hepatic enzymes.

Di(2-ethylhexyl) phthalate (DEHP), as a widespread environmental pollutant and an endocrine disruptor, can disturb the homeostasis of thyroid hormones (THs). In order to elucidate roles of the MAPK and PI3K/Akt pathways and hepatic enzymes in thyroid-disrupting effects of DEHP, Sprague-Dawley rats were dosed with DEHP by gavage for 30 consecutive days; Nthy-ori 3-1 cells were treated with DEHP with NAC, k-Ras siRNA or inhibitors (U0126 and wortmannin). Results showed that DEHP led to histopathologic changes in rat thyroid and liver, such as the decrease in thyroid follicular cavity diameter, hepatocyte edema. Triiodothyronine (T3), thyroxine (T4) and thyrotropin releasing hormone (TRH) were reduced. DEHP caused ROS production, oxidative stress and k-Ras upregulation, thereby activating the ERK and Akt pathways in vivo and in vitro. Moreover, TRH receptor (TRHr) level was elevated after the activation of the Akt pathway and was downregulated after the inhibition of the Akt pathway. However, TRHr was not modulated by the ERK pathway. Additionally, hepatic enzymes, including Ugt1a1, CYP2b1, Sult1e1, and Sult2b1, were significantly induced after DEHP exposure. Taken together, DEHP can perturb TH homeostasis and reduce TH levels. The activated Ras/Akt/TRHr pathway and induced hepatic enzymes play vital roles in thyroid-disrupting effects of DEHP.

[Library search of UV spectra of organic environmental pollutants by temperature-constrained cascade-correlation networks].

A temperature-constrained cascade-correlation network (TCCCN) was used to identify ultraviolet (UV) spectra of organic environmental pollutants. Library search for UV spectra is more difficult than that for infrared (IR) spectra, because the UV spectra overlap more severely than IR spectra. Besides, drift and noise in the measurement will have significant effect on UV library spectra search. Therefore, neural networks with fuzzy output should be a better alternative for the library search. The TCCCN is different from the commonly used BP networks in architecture. The processing units in the TCCCN are connected in a cascade mode, and a temperature constraint is introduced. Therefore, the TCCCN can reduce overtraining and fast training speed. TCCCN was used for library search of UV spectra in the present work and the effects of network parameters and noise were investigated. Results showed that better results were obtained with the TCCCN than with conventional correlation method.

[Differential geometry expression and analysis of regionalized variables of typical pollutants concentration in terrestrial environment].

Based on the basic concepts of differential geometry in analyzing environmental data and establishing related models, the methodology for differential geometry expression and analysis of pollutants concentration in terrestrial environment was presented. As a kind of regionalized variables, the spatial distribution pattern of the pollutants concentration was transformed into 3-dimension form, and fitted with conicoid. This approach made it possible to analyze the quantitative relationships between the regionalized variables and their spatial structural attributes. For illustration purpose, several sorts of typical space fabrics, such as convexity, concavity, ridge, ravine, saddle, and slope, were calculated and characterized. It was suggested that this approach was feasible for analyzing the regionalized variables of pollutants concentration in terrestrial environment.

[Revaluation of soil heavy metals pollution in Zhangshi irrigation area of Shenyang and analysis of Cd forms in soil].

This paper revaluated the situation of cadmium (Cd) pollution in rice field soils of Zhangshi irrigation area in Shenyang. The results indicated that the soil Cd pollution of test area was still quite serious. The Cd content in brown rice samples ranged from 0.435 to 0.855 mg x kg(-1), which exceeded the national criteria for food sanitation in China, and increased by 335%-755% compared with that 20 years ago. Brown rice Cd had a significant negative correlation with soil pH, and a positive correlation with soil available Cd. The decrease of soil pH induced more soil Cd transformed into available Cd which occupied 22.8%-52.0% of the total Cd and was easy to be absorbed by rice plant, inducing the Cd in brown rice exceeded national criteria. The pollutant Cd could transfer along with surface runoff, ground water and flying dust, making the pollution extend gradually.