A total of 161 water samples were collected from five large and medium-sized city rivers and residential tap waters, Xi’an and Yan’an in Shaanxi province, Xining in Qinghai province, Lanzhou in Gansu, and Urumqi in Xinjiang province, within arid and semi-arid area (NW China). The pH, EC parameters, and concentrations of 10 major ions (F⁻, Cl⁻, HCO₃⁻, NO₃⁻, SO₄²⁻, NH₄⁺, K⁺, Na⁺, Mg²⁺, Ca²⁺) in the drinking waters (DWs) and surface waters (SWs) were analyzed to determine the ion chemistry, geochemical process, and potential anthropogenic input sources and to assess the water quality for drinking, domestic, and irrigation purposes. Durove diagrams and Gibbs diagram indicated that the ions Ca²⁺ and HCO₃⁻ dominant in DWs from Xi’an and Xining were of Ca²⁺-(HCO₃⁻ + SO₄²⁻) type, while sulfate and Na⁺ dominant in SWs, and Na⁺/K⁺-SO₄²⁻ type was for Yan River in Yan’an and Peaceful Canal in Urumqi, their water chemistry influenced by evaporation and rock dominance, and evaporation and fractional crystallization, respectively. Meanwhile, Na⁺/K⁺/Ca²⁺-HCO₃⁻/SO₄²⁻ type dominated in Huang River in Xining and Yellow River in Lanzhou, which dominated by rock weathering. The quality assessments showed that in general the drinking waters were suitable for domestic purposes. However, the high values of NO₃⁻ at some sites influenced by agricultural and industrial inputs made it unsafe for drinking and demand detailed regional drinking water investigations. The assessment of SWs showed that the waters from Yan River in Yan’an and Yellow River in Lanzhou and Huang River in Xining would be used for irrigation. However, high values of SAR, Na%, RSC, and EC at sites in Peaceful Canal restricted suitability for irrigation, and not recommended for drinking water sources. It was noted that for the sustainable development of surface water, a reduction of discharge water from human activities and/or an increase in the fresh water inflow to the surface were needed.

Many studies have highlighted the link between indoor air pollution from the burning of solid fuels for cooking and heating and the occurrence of various health problems particularly in women and children under 5 years. In developing countries, solid fuels remain the main sources of energy. The purpose of this study aims to describe the distribution of household cooking fuel types and to analyze the factors influencing household cooking energy choice in Ouagadougou. A cross-sectional survey was conducted in 2017 in 3 neighborhoods of Ouagadougou. A total of 1734 household were randomly selected. We performed a multivariable logistic regression and a multinomial logistic regression to measure the relationship between selected determinants and households’ primary cooking fuel. 59.53% of the households of Ouagadougou reported using solid fuels as the main cooking fuel. Wood is the most common primary cooking fuel used (43.93%), followed by LPG (40.41%) and then charcoal (15.60%). About 84% combine at least 2 types of energy for cooking. Cooking fuel choice is strongly influenced by the socioeconomic status, the family size, and also by the woman’s educational attainment, her age and the main cooking fuel used in her parents’ house. Actions aimed at reducing the impact of solid fuel use in the environment or health must consider these factors.

Tritium (³H) is a radioactive isotope of hydrogen. In the environment, the most common form of tritium is tritiated water (HTO). However, tritium can also be incorporated into organic molecules, forming organically bound tritium (OBT). The present study characterized the effects of tritium on the health of the fathead minnow, Pimephales promelas. Fish were exposed to a gradient of HTO (activity concentrations of 12,000, 25,000, and 180,000 Bq/L) and OBT using food spiked with tritiated amino acids (OBT only, with an activity concentration of 27,000 Bq/L). A combined exposure condition where fish were placed in 25,000 Bq/L water and received OBT through feed was also studied. Fish were exposed for 60 days, followed by a 60-day depuration period. A battery of health biomarkers were measured in fish tissues at seven time points throughout the 120 days required to complete the exposure and depuration phases. HTO and OBT were also measured in fish tissues at the same time points. Results showed effects of increasing tritium activity concentrations in water after 60 days of exposure. The internal dose rates of tritium, estimated from the tissue free-water tritium (TFWT) and OBT activity concentrations, reached a maximum of 0.65 μGy/h, which is relatively low considering background levels. No effects were observed on survival, fish condition, and metabolic indices (gonado-, hepato-, and spleno-somatic indexes (GSI, HSI, SSI), RNA/DNA and proteins/DNA ratios). Multivariate analyses showed that several biomarkers (DNA damages, micronucleus frequency, brain acetylcholinesterase, lysosomal membrane integrity, phagocytosis activity, and reactive oxygen species production) were exclusively correlated with fish tritium internal dose rate, showing that tritium induced genotoxicity, as well as neural and immune responses. The results were compared with another study on the same fish species where fish were exposed to tritium and other contaminants in natural environments. Together with the field study, the present work provides useful data to identify biomarkers for tritium exposure and better understand modes of action of tritium on the fathead minnow.

The epigenetic changes induced by environmental contaminants play important roles in the inheritance of male reproductive dysfunction. The present study investigated DNA methylation changes and some oxidative stress biomarkers induced by bisphenol A (BPA) in male offspring. A total number of 48 female albino rats were administered orally with 50 μg/kg of BPA/day during gestation and/or lactation periods. At postnatal day 60, the samples were collected from the male pups to assess the serum testosterone, malondialdehyde (MDA) level, superoxide dismutase (SOD), glutathione S-transferase, and glutathione peroxidase (GSH-Px) activities in testicular tissue. DNA methylation in both DNA (cytosine-5)-methyltransferase 3A and estrogen receptor alpha genes was detected by methylation-specific PCR. BPA exposure resulted in significant decrease in the anogenital distance, testis and epididymis weights, serum testosterone level, SOD, GST, and GSH-Px levels with significant increase in weaning body weight and the MDA level. Additionally, BPA caused marked hypermethylation within Dnmt3A and ER- ∝ genes promoter regions in the testis of rat male pups. Graphical abstract

Natural halloysite nanotubes (HNTs) with a hollow lumen have been widely applied in many fields, such as water purification, drug carriers, cosmetics, antibacterial, and scaffolds for tissue engineering. However, their in vivo toxicity is still largely unclear. The aim of this study is to evaluate sub-chronic oral toxicity of HNTs in the small intestine of mice. The results demonstrated that oral HNTs at low dose (5 mg/kg) for 30 days promoted mouse growth with no obvious adverse effect on the small intestine. The promotive effect on mouse growth disappeared after cessation of oral administration of HNTs. Oral HNTs at high dose (50 mg/kg) for 30 days induced aluminum (Al) and silicon (Si) accumulation and oxidative stress in the small intestine, which caused significant increases in the levels of cyclooxygenase-2 (COX-2) and nitric oxide synthase (iNOS) and inflammatory response and iNOS-mediated damages in the organ. Oral HNTs-induced changes in the small intestine at high dose were not observed after a 30-day recovery period. These findings provided the first evidence that oral HNTs-induced sub-chronic toxicity in the small intestine was reversible. The results suggest that HNTs at low concentration in environments have no adverse effect on mice, while there are health risks to mice under severe contamination by HNTs.

Reducing cadmium (Cd) accumulation in flue-cured tobacco is the main degree to reduce the harm of Cd to human health. In this study, a rhizobag experiment was conducted to investigate the characteristics of dissolved organic matter (DOM) in the rhizosphere of a low-Cd-accumulating tobacco line (RG11) and its role in the processes of Cd accumulation by plants. Cd concentrations in the roots and leaves of RG11 were 24.09–25.30 and 31.08–34.41% lower, respectively, than those of Yuyan5 under Cd stress. Cd exposure promoted DOM accumulation in the rhizosphere soils of the two tobacco lines. DOM concentrations in the rhizosphere soils of RG11 were 8.29–14.31% lower than those of Yuyan5 under Cd stress. RG11 presented less hydrophilic acid and hydrophilic base fractions, along with more hydrophobic acid and hydrophobic base fractions of DOM in the rhizosphere than those of Yuyan5 under Cd exposure. Fourier transform infrared spectroscopy results showed that RG11 exhibited less O–H, C–H, C=C, COO–, and C–O functional groups in rhizosphere DOM than those of Yuyan5 under Cd stress. Thus, the DOM in the rhizosphere of RG11 showed lower ability to solubilize Cd in soils, resulting in less Cd uptake by roots. This could be considered to be one of the important mechanisms of low Cd accumulation in leaves of RG11.

Pardosa pseudoannulata (Araneae: Lycosidae), as an important predator of crop pests, has served as a strong driver for ecological regulation of pests. Cadmium (Cd) is a toxic heavy metal widely distributed in the soil in China, which not only seriously pollutes the ecological environment, but also poses a great threat to the survival of organisms. Palpal bulbs are the genital organs of male spiders, playing an important role in reproductive physiology. However, the effects of long-term Cd stress on the genital organ of the primary pest predator were poorly understood. Therefore, we investigated the Cd effect on the male palpal organ of P. pseudoannulata at morphological and gene expression levels. The results showed that no obvious difference in the morphology between the Cd-treated and control groups was observed, but cell adhesion was affected at molecular level. Transcriptome sequencing analysis revealed that under long-term Cd stress, the biological processes including cell-cell adhesion via plasma-membrane adhesion molecules, cell-cell adhesion, and homophilic cell adhesion via plasma membrane adhesion molecules were the top three differentially expressed terms (p-adj < 0.001), and 51 unigenes were annotated into cadherin-related proteins, such as protocadherin, cadherin-87A, and cadherin-96Ca, among which, 18 unigenes were significantly upregulated under the Cd stress. Our outcomes indicate that the differentially expressed genes involved in cell adhesion may explain the negative effects of Cd stress on the spider genital organ, and the comprehensive transcriptome dataset will also provide a profound molecular information of the genital organ of P. pseudoannulata.

Most nations are predominately preoccupied with the need to increase economic growth amidst pressure for increased energy consumption. However, higher energy consumption from fossil fuel has its environmental implication(s) especially in a high industrial economy like China. In this context, the current study explores the interaction between pollutant emission, foreign direct investment, energy consumption, tourism arrival, and economic growth for quarterly frequency data from 1995Q1 to 2016Q4 for econometrics analysis. Pesaran’s autoregressive distributed lag–bound test traces long-run relationship between all outlined variables over the investigated period. Empirical results show positive relationship between pollutant emissions with all other variables with the exception of economic growth. This further exposes the environmental degradation in China with the curtailing strength from the GDP. The Granger causality analysis detects that CO₂ emissions and energy consumption show a two-way causality observed. Also, one-way causality existing between growth and foreign direct investment is seen running to pollutant emission. Furthermore, one-way causality is observed among foreign direct investment, energy consumption, pollutant emission, and tourism arrivals with economic growth, and this established their impact on the economic growth which will be a guide to the policy implication on how to ameliorate environmental degradation from the effect of consumption of fossil energy sources and foreign direct investment–induced pollutant emission.

Concentration of trace metals (TMs) is one of the most crucial factors determining the quality of cereal grains. The aim of this study was to evaluate the effect of digestate, manure, and NPK fertilization on TM concentration in grains and straw of two cereal crops—winter wheat (WW) and spring barley (SB)—and TM transfer from soil to plants. The experiment was carried out between 2012 and 2016. Every year, the same treatment was used on each plot: control (without fertilization), digestate, digestate + straw, cattle slurry, and mineral NPK fertilization. In general, fertilization increased the concentration of TMs that belong to the micronutrient group (Zn, Cu, Fe), particularly after application of digestate and cattle slurry. At the same time, fertilization, regardless of the fertilizer type, led to an increase in Cd concentration in the grain of WW in comparison with the control. Despite the increase in Cd and micronutrient content as a result of fertilization, the concentration of elements remained below the applicable standards. Among TMs, only Pb content exceeded the European Union limits. The increased concentration of Pb was, however, an effect of other factors, rather than fertilization. The results clearly indicated that the biogas digestate from anaerobic codigestion of cattle slurry and agricultural residue could be utilized as fertilizer in agricultural applications without a risk of contaminating the food chain with TMs.

This paper investigates the nexus between carbon emissions (CO₂) and economic growth in West Africa based on the Environment Kuznets Curve (EKC) hypothesis by utilizing spatial panel data technique to check the possible effect of spatial dependence among countries in West Africa. Our empirical findings suggest the presence of spatial dependence of carbon emissions distribution in West Africa. By examining the existence of EKC embedded within the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) approach, we conclude an inverse N-trajectory of the relationship between carbon emissions and economic growth. Furthermore, to mitigate global carbon emissions, we utilize a recurrent neural network (RNN) bidirectional long short-term memory (BiLSTM) algorithm devoid of exogenous variables and assumptions to forecast carbon emissions from the year 2015 to the year 2030 based on the predictive accuracy of our formulated algorithm. Due to the upward trends in future emission levels, we propose emissions mitigation pathways for countries in West Africa to still hold carbon emissions-related global warming well below 1.5 and 2 °C. Such mitigation pathways proposed could help implement strategic policies to minimize carbon emissions to a considerable level. As a policy implication, drafting strict environmental regulations and utilizing renewable energy technologies will help mitigate carbon emissions for all West African countries.