The ecological and economic contributions of pollinator bees to agricultural production have been threatened by the inappropriate and excessive use of pesticides. These pesticides are often applied in areas with ecological peculiarities (e.g., the Neotropical savannah-like region termed as Cerrado) that were not considered during the product development. Here, we conducted field experiments with melon (i.e., Cucumis melo L.) plants cultivated under Brazilian Cerrado conditions and evaluated the impacts of botanical (i.e., neem-based insecticide) and synthetic (i.e., the pyrethroid insecticide deltamethrin and the fungicides thiophanate-methyl and chlorothalonil) pesticides on the flower visitation rates of naturally occurring pollinator bees. Our results revealed that both honey bees (i.e., Apis mellifera L.) and non-Apis bees visited melon flowers and the intensity of bee visitation was moderately correlated with yield parameters (e.g., number of marketable fruits and fruit yield). Pesticide treatments differentially affected bee species. For instance, Plebeia sp. bees were not affected by any pesticide treatment, whereas both A. mellifera and Halictus sp. bees showed reduced visitation intensity after the application of deltamethrin or neem-based insecticides. Fungicide treatment alone did not influence the bee's visitation intensity. Deltamethrin-treated melon fields produced significantly lighter marketable fruits, and the melon yield was significantly lower in melon fields treated with the neem-based insecticide. Thus, our findings with such pollinator bees reinforce the idea that field applications of botanical pesticides may represent as risky as the applications of synthetic compounds, indicating that these alternative products should be submitted to risk assessments comparable to those required for synthetic products.

Microplastic (MP) pollution is potentially a major threat to many aquatic organisms. Yet we currently know very little about the mechanisms responsible for the effects of small MPs on phenotypes, and the extent to which effects of MPs are modified by genetic and environmental factors. Using a multivariate approach, we studied the effects of 500 nm polystyrene microspheres on the life history and immunity of eight clones of the freshwater cladoceran Daphnia magna reared at two temperatures (18 °C/24 °C). MP exposure altered multivariate phenotypes in half of the clones we studied but had no effect on others. In the clones that were affected, individuals exposed to MPs had smaller offspring at both temperatures, and more offspring at high temperature. Differences in response to MP exposure were unrelated to differences in particle uptake, but were instead linked to an upregulation of haemocytes, particularly at high temperature. The clone-specific, context-dependent nature of our results demonstrates the importance of incorporating genetic variation and environmental context into assessments of the impact of plastic particle exposure. Our results identify immunity as an important mechanism underpinning genetically variable responses to MP pollution and may have major implications for predicting consequences of MP pollution.

The effluents from nuclear mining processes contain relatively high content of radionuclides (such as uranium), which may seriously threaten the environment and human health. Herein, a novel adsorbent, porous hydroxyapatite, was prepared and proven highly efficient for removal of uranyl ions (U(VI)) given its high U(VI) uptake capacity of 111.4 mg/g, fast adsorption kinetics, and the potential stabilization of adsorbed U(VI). A nearly complete removal of U(VI) was achieved by porous HAP under optimized conditions. Langmuir model could well describe the adsorption equilibrium. The data fit well with pseudo-second-order kinetic model, suggesting that U(VI) adsorption is primarily attributed to chemisorption with porous HAP. Intraparticle diffusion analysis showed that the intraparticle diffusion is the rate-limiting step for U(VI) adsorption by porous HAP. After removal by porous HAP, the adsorbed U(VI) ions were incorporated into tetragonal autunite, which has a low solubility (log Ksp: −48.36). Our findings demonstrate that the porous HAP can effectively remediate uranium contamination and holds great promise for environmental applications.

The information acquired by high resolution quadrupole-time of flight mass spectrometry (QTOF-MS) allows target analysis as well as retrospective screening for the presence of suspect or unknown emerging pollutants which were not included in the target analysis. Targeted quantification of eight azole antifungal drugs in wastewater effluent as well as new and relatively simple retrospective suspect and non-target screening strategy for emerging pollutants using UHPLC-QTOF-MS is described in this work. More than 300 (parent compounds and transformation products) and 150 accurate masses were included in the retrospective suspect and non-target screening, respectively. Tentative identification of suspects and unknowns was based on accurate masses, peak intensity, blank subtraction, isotopic pattern (mSigma value), compound annotation using data bases such as KEGG and CHEBI, and fragmentation pattern interpretation. In the targeted analysis, clotrimazole, fluconazole, itraconazole, ketoconazole and posaconazole were detected in the effluent wastewater sample, fluconazole being with highest average concentration (302.38 ng L⁻¹). The retrospective screening resulted in the detection of 27 compounds that had not been included in the target analysis. The suspect compounds tentatively identified included atazanavir, citalopram, climbazole, bezafibrate estradiol, desmethylvenlafaxine, losartan carboxylic acid and cetirizine, of which citalopram, estradiol and cetirizine were confirmed using a standard. Carbamazepine, atrazine, efavirenz, lopinavir, fexofenadine and 5-methylbenzotriazole were among the compounds detected following the non-targeted screening approach, of which carbamazepine was confirmed using a standard. Given the detection of the target antifungals in the effluent, the findings are a call for a wide assessment of their occurrence in aquatic environments and their role in ecotoxicology as well as in selection of drug resistant fungi. The findings of this work further highlights the practical benefits obtained for the identification of a broader range of emerging pollutants in the environment when retrospective screening is applied to high resolution and high accuracy mass spectrometric data.

The presence of xenobiotics in the aquatic environment has drawn scientific concern due to possible detrimental effects on the ecosystems. With EU Decision 2015/495, a first Watch list of compounds that could potentially represent a threat for the environment was created, with the objective of gathering high quality monitoring data and support their prioritization. Literature data are still very scarce and the presence of many of the compounds has not been investigated thoroughly. In this study, all the 17 compounds of the EU Watch list 2015/495 were monitored in 14 sampling locations, comprised of freshwater and, for the first time, wastewater. The study was carried out in the Ebro delta, in the north east of Spain, a representative and crucial area not only for its environmental and naturalistic significance, but also for Spain’s productivity, especially as regards rice agriculture. Results show that contamination originates both from wastewater treatment plants (WWTPs) and agricultural activities. High levels of pharmaceuticals were detected in wastewater, with azithromycin and diclofenac present at mean concentrations of 1.65 μg/L and 636 ng/L respectively. In freshwater samples, besides antibiotics and diclofenac, substantial contamination by pesticides was reported, with oxadiazon reaching up to 591 ng/L and imidacloprid being present in 93% of samples. Moreover, the study provided insight into the origin of the selected contaminants. The removal of the studied micropollutants in WWTPs was low to moderate. The assessment of risk quotients, calculated based on the available PNECs, demonstrated that the concentrations recorded for these compounds may pose a significant risk in most sampling sites.

Nitrogen (N) deposition may alter physiological process of plants in grassland ecosystem. However, little is known about the response mechanism of individual plants in alpine regions to N deposition. We conducted a field experiment, and three treatments including 0 kg Nha⁻¹year⁻¹ (CK), 8 kgNha⁻¹year⁻¹ (Low N), and 72 kg N ha⁻¹ year⁻¹ (High N) were established to simulate N deposition in alpine meadow of Qinghai-Tibetan plateau. Our objectives were to determine the influence of N deposition on photosynthesis of different functional types of herbage species in alpine meadow, and finally characterize the links of plant productivity and photosynthesis with soil nutrients. The results showed that responses of alpine plants were species-specific under N deposition. Compared with grass species Agropyron cristatum and forb species Thalictrum aquilegifolium, the sedge species Carex melanantha was much more sensitive to N deposition; a lower N load (8 kgNha⁻¹year⁻¹) can cause a negative effect on its photosynthesis and productivity. Additionally, N deposition can promote plant N uptake and significantly decreased the C (carbon)/N (nitrogen) ratio. Compared with CK and low N deposition, high N deposition inhibited the photosynthesis and growth of the forb species Thalictrum aquilegifolium and sedge species Carex melanantha. In all three functional types of herbage species, the grass species A. cristatum tended to show a much higher photosynthetic capacity and better growth potential; thus, suggesting that grass species A. cristatum will be a more adaptative alpine plants under N deposition. Our findings suggested that plant photosynthetic responses to N deposition were species-specific, low N deposition was not beneficial for all the herbage species, and N deposition may change plant composition by the differential photosynthetic responses among species in alpine grassland. Plant composition shift to grass-dorminant in alpine regions might be attributed to a much higher photosynthetic potential and N use efficiency of grass species.

Di(2-ethylhexyl)phthalate (DEHP) is an ubiquitous and emerging contaminant that is widely present in food, agricultural crop, and the environment, posing a potential risk to human health. This study utilized the nematode Caenorhabditis elegans to decipher the toxic effects of early life exposure to DEHP on aging and its underlying mechanisms. The results showed that exposure to DEHP at 0.1 and 1.5 mg/L inhibited locomotive behaviors. In addition, DEHP exposure significantly shortened the mean lifespan of the worms and further adversely affected pharyngeal pumping rate and defecation cycle in aged worms. Moreover, DEHP exposure also further enhanced accumulation of age-related biomarkers including lipofuscin, lipid peroxidation, and intracellular reactive oxygen species in aged worms. In addition, exposure to DEHP significantly suppressed gene expression of hsp-16.1, hsp-16.49, and hsp-70 in aged worms. Further evidences showed that mutation of genes involved in insulin/IGF-1-like signaling (IIS) pathway (daf-2, age-1, pdk-1, akt-1, akt-2, and daf-16) restored lipid peroxidation accumulation upon DEHP exposure in aged worms, whereas skn-1 mutation resulted in enhanced lipid peroxidation accumulation. Therefore, IIS and SKN-1 may serve as an important molecular basis for DEHP-induced age-related declines in C. elegans. Since IIS and SKN-1 are highly conserved among species, the age-related declines caused by DEHP exposure may not be exclusive in C. elegans, leading to adverse human health consequences due to widespread and persistent DEHP contamination in the environment.

Climatic stressors and chemicals should not be treated as isolated problems since they often occur simultaneously, and their combined effects must be evaluated including their possible interactive effects. In the present study we subjected springtails (Folsomia candida) to combined exposure to phenanthrene and dynamic heat cycles in a full factorial experiment. In a microcosm experiment, we studied the population growth of springtails subjected to a range of sub-lethal concentrations of phenanthrene. During the 28-day experiment we further subjected microcosms to varying numbers of repeated dynamic heat cycles (0–5 cycles) simulating repeated heat waves. We found a synergistic interaction between the effects of phenanthrene and the number of heat waves on both body mass of adults and juvenile production of F. candida showing that the negative effects of phenanthrene were intensified when animals were heat stressed, and/or vice versa. This interaction was not related to internal concentrations of phenanthrene in adult springtails, nor was it due to altered degradation of phenanthrene in soil. We argue that both phenanthrene (by its partitioning into membrane bilayers) and heat have detrimental effects on the physical conditions of cellular membranes in a dose-dependent manner, which, under extreme circumstances, can increase membrane fluidity to a level which is sub-optimal for normal membrane functioning. We discuss the possibility that the synergistic interactions subsequently reduce life-history parameters such as growth and reproduction.

Decabromodiphenyl ether (BDE-209) is commonly used as a flame retardant, usually in products that were utilized in electronic equipment, plastics, furniture and textiles. To identify the impacts of BDE-209 on the male reproductive system and the underlying toxicological mechanisms, 40 male ICR mice were randomly divided into four groups, which were then exposed to BDE-209 at 0, 7.5, 25 and 75 mg kg−1 d−1 for four weeks, respectively. With regard to the in vitro study, GC-2spd cells were treated with BDE-209 at 0, 2, 8 and 32 μg mL−1 for 24 h, respectively. The results from the in vivo experiments showed that BDE-209 resulted in damage to the testis structure, led to cell apoptosis in testis and decreased sperm number and motility, while sperm malformation rates were significantly increased. Moreover, BDE-209 could induce oxidative stress with decreased testosterone levels, result in DNA damage and activate DNA damage response signaling pathways (ATM/Chk2, ATR/Chk1 and DNA-PKcs/XRCC4/DNA ligase Ⅳ). The data from the in vitro experiments showed that BDE-209 led to cytotoxicity by reducing cell viability and increasing LDH release as well. BDE-209 also induced DNA strand breaks, cell cycle arrest at G1 phase and elevated reactive oxygen species (ROS) level in GC-2 cells. These results suggested that BDE-209 could lead to male reproductive toxicity by inducing DNA damage and failure of DNA damage repair which resulted in cell cycle arrest and apoptosis of spermatogenic cell. The present study provided new evidence to elucidate the potential mechanism of male reproductive toxicity induced by BDE-209.

The concentrations and seasonal variations of polycyclic aromatic hydrocarbons (PAHs) in air and seawater dissolved samples from the coastal area of Dalian were investigated, as well as their air-water exchanges. The average concentrations of PAHs were 27.5 ± 14.6 ng/m³ and 49.5 ± 20.5 ng/L in the air and water, respectively. Phenanthrene was the dominant congener in both air and water dissolved phase. Seasonality was discovered in the air with the concentrations higher in winter than in summer, but not in the water dissolved phase. Air-water exchange trends also displayed apparent seasonality with 3–4 ring PAHs generally being volatilization or equilibrium in summer but deposition in winter, which highlighted the important influence of temperature on the air-water exchange direction of PAHs. The air-water exchange fluxes of individual PAH congeners ranged from −24331 to 6541 ng/m²/d, and the highest deposition and volatilization fluxes both appeared at the industrial areas, which emphasized the influence of point source emission to the magnitude of air-water diffusion flux of PAHs. Multivariate source apportionment approaches, including principle component analysis, diagnostic ratios, and positive matrix factorization, were conducted, which suggested that PAHs in water originated from multiple sources. Frequent port transport correlated vehicle/ship emission rather than coal combustion may be the primary contributor of PAHs to the coastal air and water.