The concentration of certain heavy metals in various foods (fruits, cereals, legumes, and bee products) produced in industrial and urban cities is increasing each year following industrial development. Quality of honey and its contamination by different polluting agents are related essentially to its production environment, or it can arise from beekeeping practices. In the present study, the determination of physicochemical properties: moisture, pH, total acidity, electric conductivity, hydroxymethylfurfural (HMF), sugars, and chloramphenicol (CAP) residues; the metal content by determination of two toxic metals levels: lead (Pb) and cadmium (Cd); and other trace elements: magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), and nickel (Ni) in 23 different honey samples collected from North regions of Algeria were investigated. The physicochemical properties and the metal contents were found within the ranges established by the international standards. For the antibiotic residues, only four honey samples are contaminated by CAP. Metals were found in non-significant values and are in safety baseline levels for human consumption except Mg which exceed the limits. These results suggested that honey could be used as an indicator to detect contaminating agents from the environment since bees are excellent sentinels for assessing environmental contamination because of their physiological and biological characteristics.

We tested the effect of seed hydro- and proline-priming on cadmium (Cd) tolerance in maize plants. Soil supplemented with two concentrations of cadmium was used for the investigation. Cadmium content, fresh and dry mass, shoot length, leaf length and width, chlorophyll, proline, sugar and protein content, and antioxidant potential in 4-week-old plants were analysed. Cadmium content in soil and maize shoots was determined by flame atomic absorption spectrometry. Accumulation of Cd was observed for all plants, and highest Cd concentration was recorded in seedlings grown from proline-primed seeds with no visual signs of Cd toxicity. In proline-primed plants, increase in leaf length, photosynthetic pigments, and sugar and proline content as well as changes in antioxidant enzyme activities was recorded. Results obtained in this study suggest that proline-priming of maize seeds induces activation of defensive mechanisms, such as proline and sugar synthesis, which in return alleviates Cd toxicity on maize growth with increased Cd accumulation comparing to control plants.

Sixteen priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the water dissolved phase (DP), suspended particulate matter (SPM), and sediment collected from the water source zone of the Pearl River Delta region. The sum of 16 PAH concentrations ranged from 92.8 to 324 ng/L in the water DP, from 28.8 to 205 ng/L in the SPM, and from 55.7 to 381 ng/g (d.w.) in the sediment. Compared with other areas globally, the PAH levels were considerably moderate in the DP and SPM and relatively low in the sediment. Spatial distribution of PAHs was site-specific, and relatively higher PAH levels were found in the areas with dense population and heavy traffic. The PAH profile was dominated by two- and three-ring PAHs, and PAH pollution was identified of pyrolytic origins. Based on risk quotient, the ecological risk in water was ranked as moderate, but the adverse health risk associated with water ingestion was minimal. Naphthalene and fluorene of the sediment samples showed potential biological impairment in some locations; nevertheless, the mean effects range median quotient suggested that the ecological risk of multiple PAHs was quite low (less than 10% incidence of adverse effects).

The Lot river, a major tributary of the downstream Garonne river, the largest river on the Northern side of the Pyrenees Mountains, was intensively studied in the 1970s. A pioneering program called “Lot Rivière Claire” provided a diagnosis of water quality at the scale of the whole watershed and proposed an ambitious program to manage nutrient pollution and eutrophication largely caused by urban wastewater releases. Later on, the implementation of European directives from 1991 to 2000 resulted in the nearly complete treatment of point sources of pollution in spite of a doubling of the basin’s population. At the outlet of the Lot river, ammonium and phosphate contamination which respectively peaked to 1 mg N-NH₄ L⁻¹ and 0.3 mg P-PO₄ L⁻¹ in the 1980s returned to much lower levels in recent years (0.06 mg N-NH₄ L⁻¹ and 0.02 mg P-PO₄ L⁻¹), a reduction by a factor 15. However, during this time, nitrate contamination has regularly increased since the 1980s, from 0.5 to 1.2 mg N-NO₃ L⁻¹ in average, owing to the intensification of agriculture and livestock farming. Application of the Riverstrahler model allowed us to simulate the water quality of the Lot drainage network for the 2002–2014 period. We showed that, with respect to algal requirements, phosphorus and silica are well balanced, but nitrogen remains largely in excess over phosphorus and silica. This imbalance can be problematic for the ecological status of the water bodies. Using the model, for simulating various scenarios of watershed management, we showed that improvement of urban wastewater treatment would not result in any significant change in the river’s water quality. Even though arable land occupies a rather limited fraction of the watershed area, only the adoption of better farming practices or more radical changes in the agro-food system could reverse the trend of increasing nitrate contamination.

Fetal exposure to polychlorinated biphenyls (PCBs), polychlorinated-p-dibenzodioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) have been associated with a number of adverse health outcomes. Although the placenta acts as a barrier between the mother and the fetus, these contaminants transfer through the placenta exposing the fetus. Several studies have investigated placental transfer, but few have assessed the co-variation among these contaminants. Maternal blood, cord blood, and cord tissue were collected from 41 Japanese mother-infant pairs and analyzed for dioxin-like PCBs and PCDD/Fs. Hierarchical cluster analysis followed by principal component analysis were used to assess the co-variation. Two stable clusters of dioxin-like PCBs were found in maternal and cord blood. One cluster of low/medium chlorinated dioxin-like PCBs was present in all three matrices with 2,3’,4,4’,5-PeCB(#118) and 3,3’,4,4’,5-PeCB(#126) explaining the majority of the clusters’ variances. Medium/high chlorinated dioxin-like PCBs clustered in maternal blood and cord blood but not in cord tissue. 2,3,4,4’,5-PeCB(#114) and 2,3,3’,4,4’,5,5’-HpCB(#189) explained the majority of the clusters’ variances. There was a substantial correlation between the sum of dioxin-like PCBs and total PCDD/F in all three matrices. The sum of the four suggested PCBs plus 3,3’,4,4’-TeCB(#77) correlated well with total PCDD/F in all three matrices. Apart from the dioxin-like PCBs, little co-variation existed among the studied contaminants. The five PCBs can be used as fetal exposure markers for dioxin and dioxin-like PCBs in maternal and cord blood respectively. In cord tissue, more higher chlorinated dioxin-like PCBs need to be measured as well.

Nano-silicon (Si) may be more effective than regular fertilizers in protecting plants from cadmium (Cd) stress. A field experiment was conducted to study the effects of nano-Si on Cd accumulation in grains and other organs of rice plants (Oryza sativa L. cv. Xiangzaoxian 45) grown in Cd-contaminated farmland. Foliar application with 5~25 mM nano-Si at anthesis stage reduced Cd concentrations in grains and rachises at maturity stage by 31.6~64.9 and 36.1~60.8%, respectively. Meanwhile, nano-Si application significantly increased concentrations of potassium (K), magnesium (Mg), and iron (Fe) in grains and rachises, but imposed little effect on concentrations of calcium (Ca), zinc (Zn), and manganese (Mn) in them. Uppermost nodes under panicles displayed much higher Cd concentration (4.50~5.53 mg kg⁻¹) than other aerial organs. After foliar application with nano-Si, translocation factors (TFs) of Cd ions from the uppermost nodes to rachises significantly declined, but TFs of K, Mg, and Fe from the uppermost nodes to rachises increased significantly. High dose of nano-Si (25 mM) was more effective than low dose of nano-Si in reducing TFs of Cd from roots to the uppermost nodes and from the uppermost nodes to rachises. These findings indicate that nano-Si supply reduces Cd accumulation in grains by inhibiting translocation of Cd and, meanwhile, promoting translocation of K, Mg, and Fe from the uppermost nodes to rachises in rice plants.

Effective information about ecosystem services is essential to help optimize and prioritize activities that support conservation planning in the face of land use and climate changes. This study shows an approach that integrates several dissimilar models for assessing water-related ecosystem services to predict values in 2050 under three land use scenarios in the Yanhe watershed. The simulated output variables pertaining to water yield and sediment yield were used as indicators for two ecosystem-regulating services, i.e., water flow regulation and erosion regulation, which were quantified using the soil and water assessment tool (SWAT) model. The model results were translated into a relative ecosystem service valuation scale, which facilitated the analysis of spatial and seasonal changes and served as the basis for the applied mapping approach. The simulated results indicate that higher water-related regulation services were concentrated in the middle and lower reaches of rivers with high water yield and low sediment erosion. The highest water flow regulation services occurred in summer; nevertheless, this was when erosion regulation services were the lowest compared to other periods in 2050. A comparison of the three land use scenarios showed differences in the water-related regulation services. Scenario 1, with high forest coverage, had the highest erosion regulation services, but the water flow regulation services were the lowest. Scenario 3 showed the reverse pattern. Scenario 2 had intermediate water flow regulation and erosion regulation. Increasing vegetation cover in the watershed is conducive to controlling water and soil erosion but could lead to a decline in available water resources. Spatial mapping is a powerful tool for displaying the spatiotemporal differences in the water-related regulation services delivered by ecosystems and can help decision makers optimize land use in the future, with the goal of maximizing the benefits offered by ecological services in the Yanhe watershed.

This study describes the histopathological effects of carbaryl in the spleen of Levantine frog, Pelophylax bedriage. Due to its primary role in immune system, it is important to research the toxic effects of pesticides, which play an important role in environmental pollution, on spleen. To that end, adult frogs were exposed to carbaryl for 96 h. Experimental groups contained low dose, (0.05 mg/g), medium dose (0.1 mg/g) and high dose (0.2 mg/g). After following exposure to carbaryl, the frogs were euthanised and dissected. In low-dose group, there were no important changes in spleen tissue. In medium-dose group, prominence in haemorrhage just below the capsule and an increase in the melanomacrophage number were determined. In high-dose group, in addition to increases in the melanomacrophages, separations in capsule, haemorrhage below capsule and within splenic tissue, sinusoidal enlargement, congestion in dilated sinusoid, hypertrophic plasma cells and fibrosis were determined as important histological lesions in exposed frogs. This study clearly showed that carbaryl caused important histopathological damages in splenic tissue of Pelophylax bedriagae. In view of these findings, it can be said that this insecticide has the capacity to disrupt spleen’ functions.

In recent years, researches on the impact of nanometals on the state of soil ecosystems, including silicon, which is known to have a positive effect on plants under stressful conditions, have become relevant. The aim of this study was to assess the biological effects of nanoparticles (NP) of SiO₂ on the plant Solanum tuberosum. Testing of biological activity of NP SiO₂ on potato tubers was carried out on the example of five concentrations of metal increasing exponentially (0.03, 0.09, 0.18, 0.21, and 0.36 g/kg of potatoes) and control (without processing of NP SiO₂). We have shown that on the 21st day of the experiment after tuber treatment, the average mass of tuber in concentrations 0.18 and 0.21 g/kg of NP SiO₂ increased by 6.6% and 2.2%, respectively; stimulation of root length by 27.8–21.0%, the length of sprouts increased to 55.3%, and at a concentration of 0.36 g/kg on the 14th and 45th days, there was a maximum accumulation of Si in different parts of the plants. Analysis of chlorophyll content in the sprouts Solanum tuberosum showed that concentrations of nanoform SiO₂ 0.03–0.21 g/kg chlorophyll were higher than control by 48.8% and content of carotenoids by 29.7%. According to the results of field studies, the maximum mass of potato stems and tubers was observed at concentrations of 0.09 g/kg and 0.18 g/kg NP SiO₂, which confirmed the absence of toxic properties of NP SiO₂. The absence of the toxic effect of the investigated range of concentrations of NP SiO₂ from 0.03 to 0.36 g/kg was also confirmed by electrophoretic mobility of plant DNA molecules after incubation with silicon nanoparticles in vitro.

Cadmium (Cd) can be transferred and accumulated in spiders, posing a survival risk to them. To analyze potential biological damage caused by Cd accumulation and relevant detoxification strategies employed by spiders in response to Cd exposure, we conducted transcriptome analysis of the 5th instar spider P. pseudoannulata, a common spider species playing a vital role in natural pest control in agricultural fields of southern China. We obtained 92,778 unigenes with an average length of 1104 bp and identified 302, 655, and 424 differentially expressed genes (DEGs) in the spiders fed with Cd-containing fruit flies for 2, 5, and 8 days, respectively. Results showed that the body mass of Cd-containing P. pseudoannulata were reduced when compared with controls, presumably due to delayed maturation of tissues and organs. Meanwhile, functional analysis of DEGs indicated that Cd may have a negative effect on neural signal transduction and molt cycle of the spider. For defense strategies, detoxification enzymes like glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and P450, and typical proteins like heat shock protein and metallothionein were all differentially expressed in response to Cd stress. Besides, innate immune responses like toll-like receptor signaling pathways were also upregulated. Multiple critical Cd-responsive genes involved in biological damage, detoxification, and immune response were identified, providing referable foundation for further research on Cd toxicity to P. pseudoannulata.