Elements in potable groundwater in Rugao longevity area, China: Hydrogeochemical characteristics, enrichment patterns and health assessments

A study on the impact of the number of family generations on intergenerational support for centenarians: a study in a Chinese 'longevity city'

BACKGROUND

As a natural source of support for the elderly, the family is an important channel for achieving a sense of security, happiness, and worthiness in old age. In this study, we analysed the characteristics of intergenerational support in families of centenarians and explored the impact of the number of family generations on intergenerational support.

METHODS

We conducted a cross-sectional survey between April 2020 and January 2021 among 62 elderly people aged 99+ in Rugao, China, one of six 'longevity cities' in the world. Assisted by the researchers, centenarians completed questionnaires with details pertaining to general demographics, intergenerational support, and other aspects. We used a logistic regression model to analyse the influence of the number of family generations on intergenerational support that the centenarians received with respect to economic, living, and emotional aspects.

RESULTS

Centenarians were primarily recipients of care in their families, and received intergenerational support mainly for their declined physical functions and limited self-care ability. The study results revealed that the greater the number of generations comprising the family, the greater was the intergenerational life care and emotional comfort provided for centenarians by the family.

CONCLUSIONS

In this study, we found a positive effect of the number of family generations on intergenerational support for centenarians. The government and society should promote the tradition of respecting, caring for, and honouring the elderly while paying close attention to the dynamic changes in the family structure of centenarians in promoting high-quality and sustainable development of the people, economy, and society.

Transport of micron-sized polyethylene particles in confined aquifer: Effects of size, aging, and confining pressure

Contamination of groundwater by microplastics (MPs) is increasingly reported and attracts a growing attention due to their potential risks. To understand how MPs migrate into groundwater, many previous works have investigated their transport using man-made microspheres of few microns or smaller as models. However, MPs observed in the environment are more diverse in size, shape, and type, which may have different migration behaviors. In this work, the transports of irregularly shaped polyethylene (PE) particles in the sand packed column were studied. Small MPs (22-37 μm) generally have high mobility than large MPs (44-74 μm) but can also be affected by aging. Aging decreased the hydrophobicity of the MPs and increased their surface negative charge, which can facilitate the transport of MPs. However, the physical barrier of space in the porous media might have a greater influence on their transport. The retention of the MPs was enhanced with the increase of pressure due to compression that decreased pore size. Results from this study showed that MPs of environmental features can also be transported in the groundwater but the processes could be governed by different factors, such as physical interception and steric hindrance.

Calcium and magnesium in China's public drinking water and their daily estimated average requirements

Calcium (Ca) and magnesium (Mg) in drinking water and the relevant health effects have been ignored for too long. This study aims to reveal the concentrations, spatial distributions, origins and contributions to the daily estimated average requirements of Ca and Mg in public drinking water. Using hydrochemical data of collected samples of public drinking water in 314 cities across China, the contributions of Ca and Mg intakes from public drinking water to their daily estimated average requirements (EARs) were assessed. And the significance of Ca/Mg ratio and total hardness (TH) was evaluated as well. The Ca and Mg concentrations of the samples were in the range of 2.5-155.1 mg/L and 0.2-81.9 mg/L, with an average of 40.4 mg/L and 12.4 mg/L, respectively. There exist obvious differences in Ca and Mg concentrations in different regions, under the impact of climate conditions and water-rock interactions. The intake of Ca via the consumption of public drinking water for adults may be twice as much as that for other age groups. In cities with high Ca levels in public drinking water, the Ca contributions to EAR could reach up to 51.59% for adults. By contrast, Mg in drinking water is an important and even the main pathway to ingest Mg for infants and children. Therefore, public drinking water is critical for Ca and Mg intake among urban residents of China. Besides, attention should be paid to the health effects of high Ca/Mg ratio and low TH in public drinking water, especially in southern China. This research is the first systematic and comprehensive national scale study of Ca and Mg in public drinking water and can provide an important reference to improve healthy public drinking water standards around the world.

Trace elements in public drinking water in Chinese cities: Insights from their health risks and mineral nutrition assessments

The trace elements in the public drinking water have a duality: on the one hand, trace elements play an important role in maintaining human metabolism; on the other hand, high trace elements levels lead to significant health risks. To determine the impacts of trace elements in the public drinking water on physical health in China, water samples were collected from 314 Chinese cities to analyze the concentrations and spatial distributions of trace elements on a national scale. On this basis, the non-carcinogenic health risk assessments and the nutrient-based scores of trace elements (NSTEs) were applied to evaluate the public drinking water quality in terms of safety and nutrition. Most of the water samples were weakly alkaline: pH values fell in the range of 6.62-8.54, with a mean of 7.80. The results indicated that Sr and F^- had the highest concentrations in public drinking water, with averages of 0.3604 mg/L and 0.2351 mg/L, respectively. Moreover, hazard index (HI) values in different regions followed the order: northwest China (NWC) > northern China (NC) > Qinghai-Tibetan Plateau (QT) > southern China (SC). The percentages of water samples with HI > 1 in SC, NC, NWC, and QT were 5.49%, 16.82%, 25.81%, and 16.67%, respectively, indicating that the public drinking water in some cities had significant non-carcinogenic health risks. In addition, the intakes of Mn, Fe, Cu, and Rb through public drinking water made negligible contributions to their recommended nutrient intakes. In contrast, trace elements like Sr, F, B, Li, Mo, etc., contributed a lot. The NSTEs in NWC and most parts of NC were relatively high with averages of 8.0300 and 11.2082, respectively; however, the NSTEs in SC and the northeast part of NC were low with averages of 3.3284 and 5.2106, respectively. The results from this study provide a reference for establishing the public drinking water standards and improving drinking water quality.

Hydrochemical characteristics and quality assessment of shallow groundwater in Yangtze River Delta of eastern China

Water resource is in high demand within the Yangtze River Delta, given its developed economy. Long-term exploitation of this resource has posed risks of artificial pollution and seawater intrusion to the shallow groundwater. This study aims to reveal the hydrochemical characteristics and health risks of shallow groundwater in the coastal plain of the Yangtze River Delta, as well as to discuss the possible factors affecting groundwater quality. Standard methods for hydrochemical parameter measurements, water quality assessment, and health risk models were applied to fulfill the objectives of the study. The results showed that the shallow groundwater was slightly alkaline, and the average values of total dissolved solids (TDS) and total hardness (TH) were 930.74 mg/L and 436.20 mg/L, respectively. The main hydrochemical types of groundwater were HCO₃-Ca·Mg and HCO₃-Ca·Na, accounting for 44.3% and 47.5%, respectively. In addition, As concentration was generally high, with a mean value of 0.0115 mg/L. The principal factors affecting the groundwater components include water-rock interactions (especially silicate), cation exchange, seawater intrusion, and human activities. The data also showed that As is strongly influenced by the redox of Fe, Mn, and NO₃^-. The results of the groundwater quality evaluation indicated that the shallow groundwater in some regions was unsuitable for drinking and agricultural irrigation. Health risk assessment showed that 44.3% of the water samples had significant health risks, which was attributed to the high As concentration. Therefore, it is urgent to establish long-term As monitoring to maintain sustainable groundwater management and drinking water safety. The results of this study provide essential data for water resource management and human health security in the Yangtze River Delta.

Characteristics and Causes of Changing Groundwater Quality in the Boundary Line of the Middle and Lower Yellow River (Right Bank)

The alluvial plain in the middle and lower reaches of the Yellow River is an important agricultural production base that affects groundwater quality. Groundwater quality in the region is related to the residential and production uses of water by local residents. Samples of shallow groundwater and river water were collected from the right bank of the middle and lower reaches of the Yellow River to determine the evolution and causes of hydrochemical characteristics, and the relationship between the hydrochemical evolution of river water and groundwater was explored. The results showed that the shallow groundwater in the area received lateral recharge from the Yellow River water. The closer to the Yellow River the groundwater was, the higher the SO42−, Cl−, and Na+ concentrations and the lower the HCO3− and Mg2+ concentrations were. Agriculture and aquaculture has influenced and complicated the hydrochemical types of shallow groundwater in recent decades. The groundwater in the area was jointly affected by water–rock interactions and evaporation concentrations; a strong cation exchange effect was detected. Arsenic exceeded the limit in some shallow groundwater, which was mainly distributed in the Yellow River alluvial plain and caused by the reductive sedimentary environment of the Yellow River alluvial plain. The “three nitrogen”, NH4+-N, NO2−-N, and NO3−-N, demonstrated sporadic local excesses in shallow groundwater, which were related to human activities, such as aquaculture.