Effects of magnetic hydroxyapatite loaded biochar on Cd removal and passivation in paddy soil and its accumulation in rice: a 2-year field study.

Stabilized cadmium (Cd) was extremely easy to be re-released into the environment. The study was aim to explore the Cd removal efficiency and passivation in paddy soil by magnetic hydroxyapatite loaded biochar (MHBC), and to investigate the effect of MHBC on Cd accumulation and yield of rice with low Cd accumulation cultivar named ZhuLiangYou189 (ZLY189) and conventional cultivar named ZhuLiangYou929 (ZLY929) in 2-year field trials. These results shown that MHBC under the high dosage of 25.2 t/ha can effectively decrease the bioavailable Cd (from 0.4 to 0.24 mg/kg) and total Cd (from 1.42 to 0.86 mg/kg). For ZLY929, only with the dosage of 25.2 t/ha MHBC, the grain Cd content can meet the contaminant limits in grain (≤ 0.2 mg/kg) during 2 years. While for ZLY189, the grain Cd content in 6.3 t/ha, 12.5 t/ha, and 25.2 t/ha decreased to 0.13 ~ 0.17 mg/kg, to 0.07 ~ 0.10 mg/kg, and to 0.05 ~ 0.08 mg/kg during 2 years, respectively. What's more, the application of MHBC has no environmental risk and increase grain yield by boosting soil nutrient substance. Thus, the application of MHBC was a promising remediation technology in Cd-contaminated paddy soil.

Reduction of cadmium bioavailability in paddy soil and its accumulation in brown rice by FeCl3 washing combined with biochar: A field study.

Cadmium (Cd) removal from paddy soil to reduce Cd accumulation in brown rice is essential for agroecology, food safety, and human health. In this study, we demonstrate that ferric chloride (FeCl3) washing combined with biochar treatment efficiently remediates Cd-contaminated paddy soil in field trials. Our results showed that 30.9 % of total Cd and 41.6 % of bioavailable Cd were removed by the addition of 0.03 M FeCl3 at a liquid/soil ratio of 1.5:1. The subsequent addition of 1 % biochar further reduced bioavailable Cd by 36.5 and 41.5 %, compared with FeCl3 washing or biochar treatment alone. The principal component regression analysis showed that the Cd content in brown rice was primarily affected by the bioavailable Cd in soil. The combined remediation contributed to the decreased Cd contents in brown rice by 45.5-62.5 %, as well as a 2.7-11.8 % increase in rice yield. The Cd contents in brown rice decreased to 0.12 and 0.04 mg kg-1 in two cultivars of rice (Zhuliangyou189 and Zhuliangyou929), lower than the national food safety standard limit value of China (0.2 mg kg-1). Meanwhile, the combined remediation promoted the restoration of soil pH and organic matter as well as the improvement of available nutrients. This finding suggests that the combination of FeCl3 washing and biochar is an effective remediation strategy to minimize Cd bioavailability in paddy soil, and improves soil quality, thus contributing to food safety.

Insights into deep decline of As(III) leachability induced by As(III) partial oxidation during lime stabilization of As-Ca sludge.

The enhancing effect of As(III) oxidation on As stabilization by lime is routinely attributed to the lower solubility of Ca arsenates than Ca arsenites. However, this routine explanation is insufficient for the scenario of As(III) partial oxidation, in which Ca arsenites still predominate As leachability due to the relatively high solubility. In this study, an As-Ca sludge with a high As(III) content (96 g/kg, 55% of the As(tot)) was treated by oxidant-lime to clarify the positive effect of As(III) partial oxidation. Lime alone only reduced As(tot) leaching concentrations from 541 to 4.9 mg/L (4.3 mg/L of As(III) and 0.6 mg/L of As(V)), failing to meet the regulatory limit (2.5 mg/L). After partial oxidation of As(III), lime treatment could further reduce As(III) leaching concentrations from 4.3 to below 1.9 mg/L, whereas As(V) remained stable at about 0.6 mg/L. Qualitative and quantitative analyses based on XRD, SEM-EDS, TG, and thermodynamic modeling suggested that the solubility of newly-formed amorphous Ca arsenites (CaHAsIIIO3•xH2O) after lime treatment determined the final As(III) leachability. The CaHAsIIIO3•xH2O formed at lower As(III) contents due to As(III) partial oxidation had lower solubility products and possibly higher crystallinity, resulting in the lower As(III) leachability. This study provides new insights into the role of As(III) partial oxidation in deep decline of As(III) leachability during lime stabilization, guiding the treatment of As-Ca sludge as well as other As(III)-bearing solid wastes.

Effect of family "upward" intergenerational support on the health of rural elderly in China: Evidence from Chinese Longitudinal Healthy Longevity Survey.

As health challenging rural elderly in an aging population, more attention is being paid on impact of family intergenerational support on the health of the elderly. This paper investigates the effects of children's intergenerational economic support and non-economic support on physical, mental, and functional health of rural elderly in China in the mean while. This paper applies the 2014 Chinese Longitudinal Healthy Longevity Survey (CLHLS), in particular, applying exploratory factor analysis to ascertain latent variables and Structural Equation Model (SEM), and analyzes the impacts of "Upward" intergenerational support on health of rural elderly. As resulted, after controlling the socioeconomic status of the rural elderly, the family "upward" intergenerational support influences the elderly's physical health at a percentage of 11.7%, mental health 29.8%, and physiological function 12.6%. Moreover, "Upward" economic support has a positive effect on physiological function (P<0.05). "Upward" non-economic support has negative effects on physiological function and mental health (P<0.05), while it has a positive effect on physical health. In addition, economically independent rural elderly are more likely to benefit from the health of "upward" intergenerational support, especially mental health. In particular, those results are robust. "Upward" intergenerational support plays an important role for the health of rural elderly. For the rural elderly of economic independence, to improve the quality of care and spiritual support, it is important to solve the health problems. In addition, it is necessary to build a comprehensive old-age security and support system for family, community, and society jointly to improve the health of the rural elderly.

Effect of medical insurance and family financial risk on healthcare utilisation by patients with chronic diseases in China: a cross-sectional study.

OBJECTIVE: To assess the joint cumulative effects of medical insurance and family health financial risk on healthcare utilisation among patients with chronic conditions in China. DESIGN: A nationwide population-based case-control study with multinomial logistic regression was conducted and used to estimate the ORs of healthcare utilisation against type of medical insurance and family health financial risk using the Anderson model as a theoretical framework. SETTING: China Family Panel Studies (CFPS) database. PARTICIPANTS: The study sample included 5260 patients with chronic conditions identified from the 2014 CFPS database. MAIN OUTCOME MEASURES: The participants were classified by their health insurance coverage: urban employee basic medical insurance (UEBMI), Gong Fei Medical Insurance (GFMI), new rural cooperative medical scheme (NCMS) and urban residents basic medical insurance. Healthcare utilisation was measured by assessing the care level provided by the health institutions selected by patients when they were sick. Health financial risk was measured using the cost of medical expenditures and annual family income over the past year. RESULTS: Patients were more likely to choose hospital care than care from primary health centres. Patients with NCMS preferred primary healthcare, compared with patients with no medical insurance (OR 1.852, 95% CI 1.458 to 2.352). Patients with UEBMI and GFMI made use of hospital healthcare services (OR 2.654, 95% CI 1.85 to 3.81; OR 1.629, 95% CI 1.15 to 2.30, respectively). Patients who had medium or high financial risk were more likely to choose tertiary/specialised hospital care, compared with those at low financial risk (OR 1.629, 95% CI 1.15 to 2.30; OR 1.220, 95% CI 1.04 to 1.43, respectively). CONCLUSIONS: The majority of patients chose hospital care in our sample. There was a joint effect and relationship between degree of family health financial risk and medical insurance on healthcare utilisation.