Cadmium (Cd), a ubiquitous environmental pollutant, is known to impair placental development. However, the underlying mechanisms remain unclear. The present study used in vivo and in vitro models to investigate the effects of Cd on apoptosis and autophagy in placental trophoblasts and its mechanism. Pregnant mice were exposed to CdCl₂ (4.5 mg/kg) on gestational day (GD) 9. Human JEG-3 cells were exposed to CdCl₂ (0–40 μM) for different time points. Gestational Cd exposure obviously lowered the weight and diameter of mouse placentas. Number of TUNEL-positive cells was markedly elevated in Cd-administered mouse placentas and JEG-3 cells. Correspondingly, Cd significantly up-regulated cleaved caspase-3 protein level, a key indicator of apoptosis, in murine placentas and JEG-3 cells. Simultaneously, Cd also triggered autophagy, as determined by an elevation of LC3B-II and p62 protein, and accumulation of LC3-positive puncta, in placental trophoblasts. Chloroquine an autophagy inhibitor, obviously aggravated Cd-induced apoptosis in JEG-3 cells. By contrast, rapamycin, a specific autophagy inducer, significantly alleviated Cd-triggered apoptosis in JEG-3 cells. Mechanistically, autophagy inhibited Cd-induced apoptosis mainly via degrading caspase-9. Co-localizations of p62, a classical autophagic receptor, and caspase-9 were observed in Cd-stimulated human JEG-3 cells. Moreover, p62 siRNAs pretreatment markedly blocked the degradation of caspase 9 proteins via Cd-activated autophagy in JEG-3 cells. Collectively, our data suggest that activation of autophagy inhibits Cd-induced apoptosis via p62-mediated caspase-9 degradation in placental trophoblasts. These findings provide a new mechanistic insight into Cd-induced impairments of placental and fetal development.

Nanoparticles (NPs), heavy metal and natural organic matter (NOM) may simultaneously exist in the aquatic environment, where they will affect the behavior of each other and may enhance their toxicities. Studies on the influences of interactions between NOM and heavy metal ions on the behavior of NPs are scarce. In this study, combined effects of Pb²⁺ and HA on the aggregation behavior of TiO₂ NPs in water environment were investigated by Dynamic light scattering (DLS) and Nanoparticle tracking analysis (NTA). The results illustrated that interactions between Pb²⁺ and HA could case the aggregation of TiO₂ NPs obviously. The concurrence of Pb²⁺ and HA resulted in decreased critical coagulation concentration (CCC) and increased attachment efficiencies. Meanwhile, we found that the addition sequences of HA and heavy metal clearly influenced the aggregation kinetics of TiO₂ NPs. At different addition sequences, the complex reaction between Pb²⁺ and HA changed the surface charge of TiO₂ NPs, and caused the different aggregation behavior which depended on the complex locations and complex sites. Furthermore, the excitation-emission-matrix (EEM) fluorescence spectra was used to verify the significant effects of the complex interactions between Pb²⁺ and HA on the aggregation of TiO₂ NPs. Our results would be significant for interpreting TiO₂ behavior in the complicated water system.The complexation between Pb²⁺ and HA promoted the aggregation of TiO₂ NPs, meanwhile, complex locations and complex sites played an important role.

Previous in vitro studies have implied that triphenyl phosphate (TPHP) may act as an obesogen. However, its specific contributions to the progression of obesity and related metabolic diseases are still unclear in vivo in mice. In this study, we evaluated the effects of in utero and lactational exposure to three doses of TPHP (10, 100, and 1000 μg/kg BW) on obesity and metabolic dysfunctions in adult male mice fed a low-fat diet (LFD) or high-fat diet (HFD), by examining body weight, liver weight, histopathology, blood biochemistry, gene expression, and gut microbiota compositions and metabolic functions. Results showed that TPHP exposure led to increased body weight, liver weight, fat mass, hepatic steatosis, impaired glucose homeostasis, and insulin resistance, and mRNA levels of genes involved in lipid metabolism, especially lipogenesis and lipid accumulation, were significantly altered by TPHP treatment. Gas chromatography-mass spectrometry (GC-MS) analysis further supported the changes in fatty acid composition. Intestinal flora measurements by 16S rRNA gene sequencing and ¹H NMR based fecal metabolomics indicated that TPHP treatment modulated gut microbiome composition and influenced host-gut co-metabolism, especially for bile acids and short chain fatty acids (SCFAs). These results suggest that fetal exposure to TPHP can promote the development of obesity and metabolic dysfunctions in adult mice.

In standard terrestrial ecotoxicological tests, soils usually are spiked with highly soluble metal salts leading to overestimation of bioavailability and introducing counterions that may contribute to toxicity. Leaching is suggested as an efficient method to avoid the effects of the associated counterions. The present study aimed at investigating the effects of leaching on the bioavailability and toxicity of Pb(NO₃)₂ and PbO to the potworm Enchytraeus crypticus in LUFA 2.2 soil freshly spiked or after 18 months ageing. Percolation decreased porewater Pb concentrations as well as the toxicity of both Pb forms. The influence of percolation differed between the two Pb forms and between freshly spiked and aged soils. Percolation slightly increased LC50s based on total soil Pb concentrations for Pb(NO₃)₂, but not for PbO, and only affected Pb toxicity to enchytraeid reproduction in freshly spiked soils. The differences in Pb uptake in E. crypticus and toxicity between the two Pb forms as well as between different treatments could be minimized by relating them to 0.01 M CaCl₂-extractable concentrations. In addition, body Pb concentrations could well explain enchytraeid survival across all soils and treatments, indicating its suitability as a good proxy for Pb toxicity in soil.

The issue of potential long-term or hereditary effects for both humans and wildlife exposed to low doses (or dose rates) of ionising radiation is a major concern. Chronic exposure to ionising radiation, defined as an exposure over a large fraction of the organism's lifespan or even over several generations, can possibly have consequences in the progeny. Recent work has begun to show that epigenetics plays an important role in adaptation of organisms challenged to environmental stimulae. Changes to so-called epigenetic marks such as histone modifications, DNA methylation and non-coding RNAs result in altered transcriptomes and proteomes, without directly changing the DNA sequence. Moreover, some of these environmentally-induced epigenetic changes tend to persist over generations, and thus, epigenetic modifications are regarded as the conduits for environmental influence on the genome.Here, we review the current knowledge of possible involvement of epigenetics in the cascade of responses resulting from environmental exposure to ionising radiation. In addition, from a comparison of lab and field obtained data, we investigate evidence on radiation-induced changes in the epigenome and in particular the total or locus specific levels of DNA methylation. The challenges for future research and possible use of changes as an early warning (biomarker) of radiosensitivity and individual exposure is discussed. Such a biomarker could be used to detect and better understand the mechanisms of toxic action and inter/intra-species susceptibility to radiation within an environmental risk assessment and management context.

In order for Alberta's thick bitumen to be transported through pipelines, condensates are added creating a diluted bitumen (dilbit) mixture. Recent pipeline expansion projects have generated concern about potential dilbit spills on aquatic wildlife health. Studies have suggested that polycyclic aromatic compounds (PACs) are toxic to aquatic vertebrates and could potentially also interfere with their endocrine system. The research objectives of this study were to investigate the toxicity of dilbit to developing frog embryos and to identify the molecular mechanisms of action involved. Fertilized embryos of Western clawed frog (Silurana tropicalis) were exposed for 72 h to water accommodated fractions (WAF; 0.7–8.9 μg/L TPACs) and chemically-enhanced WAFs (CEWAF; 0.09–56.7 μg/L TPACs) of Access Western Blend (AWB) and Cold Lake Blend (CLB) dilbits. Both dilbit's CEWAFs significantly increased embryonic mortality and malformation incidence in the highest treatments tested, while WAF treatments led to no visible toxic effects. Increases of the cytochrome P450 1A (cyp1a) mRNA levels were observed for all WAF and CEWAF dilbit treatments suggesting that phase I detoxification is activated in the dilbit-exposed larvae. When exposed to PAC concentrations ranging from 0.09 to 8.9 μg/L, the frogs displayed no observable malformations, but expressed significant increases of cyp1a mRNA levels (2- to 25-fold; indicating a suitable biomarker of exposure); however, when concentrations were of 46.6 μg/L or higher, both malformed frog phenotype and induction of cyp1a mRNA level (>250-fold) were measured (indicating a suitable biomarker of response). The expression of several genes related to cellular detoxification and endocrine disruption were also measured, but were not significantly altered by the treatments. In sum, cyp1a mRNA level is a highly sensitive endpoint to measure subtle molecular changes induced by PAC exposure in the frog embryos and larvae, and data suggest that PAC concentration higher than 46 μg/L would be toxic to the developing S. tropicalis.

Increasing amount of aluminum (Al) gets into aquatic ecosystem through anthropogenic activity, but the knowledge about Al migration and relationships with sediments possessing different physico-chemical properties in eutrophic lakes is limited. Here, the Al migration rule and relationships with sediment nutritions in the Hangzhou West Lake, China was investigated, where a certain amount of residual Al-salts can enter because of the pre-treatment of the Qiantang River diversion project every day. Results revealed the obvious spatial distribution heterogeneity of Al in sediment vertical direction and horizontal direction following water flow. The Al content in sediment ranged 0.463–1.154 g kg⁻¹ in Maojiabu Lake, and ranged 9.862–40.442 g kg⁻¹ in Xiaonanhu Lake. Higher Al content distributed in upper layer sediment in lake with more disturbance. Total nitrogen (TN) contents were higher 0.917–3.387 mg g⁻¹ and 0.627–0.786 mg g⁻¹ in upper layer sediment than that in lower layer in Maojiabu Lake and Xiaonanhu Lake, respectively. Total phosphorus (TP) content ranged 0.779–2.580 mg g⁻¹, in which IP and Fe/Al-P contributed 24.9–80.8% and 17.0–51.6%, respectively. Correlations between Al content with nutrition, humic acid (HA) etc. of sediment regionally varied in Maojiabu and Xiaonanhu Lake. Spatial distribution of Al-salt in eutrophic lakes closely related with the physico-chemical characteristics of nutrients, humus, human disturbance and water division parameters. Results provides new insight into Al-salts migration and references for Al-risk evaluating in eutrophic lakes.

A field study was conducted to clarify sources of atmospheric black carbon and related carbonaceous components at Rishiri Island, Japan. We quantified equivalent black carbon (eBC) particle mass and the absorption Ångström exponent (AAE), atmospheric CO and CH₄, in addition to levoglucosan in total suspended particles, a typical tracer of biomass burning. Sixteen high eBC events were identified attributable to either anthropogenic sources or biomass burning in Siberia/China. These events were often accompanied by increases of co-emitted gases such as CH₄ and CO. Specifically, we observed pollution events with elevated eBC, AAE, levoglucosan, and CH₄CO slope in late July 2014, which were attributed to forest fires in Siberia by reference to the FLEXPART model footprint and fire hotspots. In autumn, drastic increases of eBC, AAE, and levoglucosan were observed, accompanied by an eBC–CO slope of >15 ng m⁻³/ppb, resulting from long-range transport of emissions from extensive burning of crop residue on the Northeast China Plain. Other than the sources of fossil fuel combustion in China and forest fires in Siberia, we report for the first time that pollution events in northern Japan are caused by crop residue burning in China. This study elucidated valuable information that will improve understanding of the effects of biomass burning in East Asia on atmospheric carbonaceous components.

Crops are prone to various types of stress, such as caused by heavy metals, drought and pest/disease, during their life cycle. Heavy metal stress in crops poses a serious threat to crop quality and human health. However, differentiating between heavy metal and non-heavy metal stress presents a great challenge, since responses to environmental stress in crops are complex and uncertain, with different stressors possibly triggering similar canopy reflectance responses. This study aims to infer the occurrence probability of heavy metal stress (i.e., Cd stress) on a regional scale by integrating satellite-derived vegetation index and spatio-temporal characteristics of different stressors with a Bayesian method. The study area is located in the Hunan Province, China. Seven scenes of Sentinel-2 satellite images from 2016 to 2017 were collected, as well as Cd concentrations in the soil. First, the probability of rice being stressed was screened using the normalized difference red-edge index (NDRE) at all the growth stages of rice. Further, the stressed rice was used as input, along with the coefficients of spatio-temporal variation (CSTV) derived from NDRE, for a Bayesian method to infer rice exposed to Cd pollution. The results demonstrated that NDRE was a sensitive indicator for assessing stress levels in rice crops. The CSTV with a threshold of 2.7 successfully detected rice under Cd as well as abrupt stress on a regional scale. A high map accuracy for Cd induced stress in rice was achieved with an accuracy of 81.57%. This study suggests that vegetation index obtained from satellite images can assist in capturing crop stress, and that the used Bayesian method can be very useful for distinguishing a specific stressor in crops by incorporating temporal-spatial characteristic of different stressors in crops into satellite-derived vegetation index.

Understanding how mercury (Hg) accumulates in the aquatic food web requires information on the factors driving methylmercury (MeHg) contamination. This paper employs data on MeHg in muscle tissue of three black bass species (Largemouth Bass, Spotted Bass, and Smallmouth Bass) sampled from 21 reservoirs in California. During a two-year period, reservoirs were sampled for total Hg in sediment, total Hg and MeHg in water, chlorophyll a, organic carbon, sulfate, dissolved oxygen, pH, conductivity, and temperature. These data, combined with land-use statistics and reservoir morphometry, were used to investigate relationships to size-normalized black bass MeHg concentrations. Significant correlations to black bass MeHg were observed for total Hg in sediment, total Hg and MeHg in surface water, and forested area. A multivariate statistical model predicted Largemouth Bass MeHg as a function of total Hg in sediment, MeHg in surface water, specific conductivity, total Hg in soils, and forested area. Comparison to historical reservoir sediment data suggested there has been no significant decline in sediment total Hg at five northern California reservoirs during the past 20 years. Overall, total Hg in sediment was indicated as the most influential factor associated with black bass MeHg contamination. The results of this study improve understanding of how MeHg varies in California reservoirs and the factors that correlate with fish MeHg contamination.