Boscalid is one of the most frequently detected pesticides in main coastal estuaries in California, with concentrations as high as 36 μg/L. However, ecotoxicology information about boscalid to aquatic organisms is scarce. To investigate toxic effects and mechanisms of boscalid on freshwater algae Chlorella vulgaris (C. vulgaris), C. vulgaris were exposed to a range of boscalid concentrations (0, 0.8, 1.6, 2.4 and 3.2 mg/L) for 96 h to study the changes in photosynthetic pigment contents, responses of the antioxidant enzyme system and alterations in endogenous substances. Results indicated that the growth of algae and the content of chlorophyll and carotenoids were significantly inhibited by 1.6 mg/L boscalid. Reactive oxygen species (ROS) and oxidative damage of C. vulgaris could be induced by boscalid, in accordance with significant changes in ROS levels and a series of antioxidant enzyme activities. Moreover, the alterations in endogenous substances showed that boscalid could affect photosynthesis and energy metabolism of C. vulgaris. These results demonstrated that boscalid could induce impacts on C. vulgaris mainly through disturbing the photosynthesis, oxidative damage and energy metabolism. The present study provided a better understanding of the negative effects and mechanisms of bosaclid in microalgae.

Bioindicators play an important role in understanding pollution levels, bioavailability and the ecological risks of contaminants. Several bioindicators have been suggested for understanding microplastic in the marine environment. A bioindicator for microplastics in the freshwater environment does not exist. In our previous studies, we found a high frequency of microplastic pollution in the Asian clam (Corbicula fluminea) in Taihu Lake, China. In the present study, we conducted a large-scale survey of microplastic pollution in Asian clams, water and sediment from 21 sites in the Middle-Lower Yangtze River Basin from August to October of 2016. The Asian clam was available in all sites, which included diverse freshwater systems such as lakes, rivers and estuaries. Microplastics were found at concentrations ranging from 0.3-4.9 items/g (or 0.4–5.0 items/individual) in clams, 0.5–3.1 items/L in water and 15–160 items/kg in sediment. Microfibers were the most dominant types of microplastics found, accounting for 60–100% in clams across all sampling sites. The size of microplastics ranged from 0.021-4.83 mm, and microplastics in the range of 0.25–1 mm were dominant. The abundance, size distribution and color patterns of microplastics in clams more closely resembled those in sediment than in water. Because microplastic pollution in the Asian clam reflected the variability of microplastic pollution in the freshwater environments, we demonstrated the Asian clam as an bioindicator of microplastic pollution in freshwater systems, particularly for sediments.

The effect of titanium dioxide nanoparticles (nano-TiO2) on the bioaccumulation and biotransformation of arsenic (As) remains largely unknown. In this study, we exposed two freshwater algae (Microcystis aeruginosa and Scenedesmus obliquus) to inorganic As (arsenite and arsenate) with the aim of increasing our understanding on As bioaccumulation and methylation in the presence of nano-TiO2. Direct evidence from transmission electron microscope (TEM) images show that nano-TiO2 (anatase) entered exposed algae. Thus, nano-TiO2 as carriers boosted As accumulation and methylation in these two algae species, which varied between inorganic As speciation and algae species. Specifically, nano-TiO2 could markedly enhance arsenate (As(V)) accumulation in M. aeruginosa and arsenite (As(III)) accumulation in S. obliquus. Similarly, we found evidence of higher As methylation activity in the M. aeruginosa of As(III) 2 mg L−1 nano-TiO2 treatment. Although this was also true for the S. obliquus (As(V)) treatment, this species exhibited higher As methylation compared to M. aeruginosa, being more sensitive to As associated with nano-TiO2 compared to M. aeruginosa. Due to changes in pH levels inside these exposed algae, As dissociation from nano-TiO2 inside algal cells enhanced As methylation. Accordingly, the potential influence of nanoparticles on the bioaccumulation and biotransformation of their co-contaminants deserves more attention.

Illicit drugs have been identified as emerging aquatic pollutants because of their widespread presence in freshwaters and potential toxicity towards aquatic organisms. Among illicit drug residues, cocaine (COC) and its main metabolites, namely benzoylecgonine (BE) and ecgonine methyl ester (EME), are commonly detected in freshwaters worldwide at concentration that can induce diverse adverse effects to non-target organisms. However, the information of toxicity and mechanisms of action (MoA) of these drugs, mainly of COC metabolites, to aquatic species is still fragmentary and inadequate. Thus, this study was aimed at investigating the toxicity of two concentrations (0.3 and 1.0 μg/L) of COC, BE and EME similar to those found in aquatic ecosystems on zebrafish (Danio rerio) embryos at 96 h post fertilization through a functional proteomics approach. Exposure to COC and both its metabolites significantly altered the protein profile of zebrafish embryos, modulating the expression of diverse proteins belonging to different functional classes, including cytoskeleton, eye constituents, lipid transport, lipid and energy metabolism, and stress response. Expression of vitellogenins and crystallins was modulated by COC and both its main metabolites, while only BE and EME altered proteins related to lipid and energy metabolism, as well as to oxidative stress response. Our data confirmed the potential toxicity of low concentrations of COC, BE and EME, and helped to shed light on their MoA on an aquatic vertebrate during early developmental period.

Pesticides, in particular insecticides, can be very beneficial but have also been found to have harmful side effects on non-target insects. Butterflies play an important role in ecosystems, are well monitored and are recognised as good indicators of environmental health. The amount of information already known about butterfly ecology and the increased availability of genomes make them a very valuable model for the study of non-target effects of pesticide usage. The effects of pesticides are not simply linear, but complex through their interactions with a large variety of biotic and abiotic factors. Furthermore, these effects manifest themselves at a variety of levels, from the molecular to metapopulation level. Research should therefore aim to dissect these complex effects at a number of levels, but as we discuss in this review, this is seldom if ever done in butterflies. We suggest that in order dissect the complex effects of pesticides on butterflies we need to integrate detailed molecular studies, including characterising sequence variability of relevant target genes, with more classical evolutionary ecology; from direct toxicity tests on individual larvae in the laboratory to field studies that consider the potentiation of pesticides by ecologically relevant environmental biotic and abiotic stressors. Such integration would better inform population-level responses across broad geographical scales and provide more in-depth information about the non-target impacts of pesticides.

Following the widespread assumption that a majority of ubiquitous marine microplastic particles originate from land-based sources, recent studies identify rivers as important pathways for microplastic particles (MPP) to the oceans. Yet a detailed understanding of the underlying processes and dominant sources is difficult to obtain with the existing accurate but extremely time-consuming methods available for the identification of MPP.Thus in the presented study, a novel approach applying short-wave infrared imaging spectroscopy for the quick and semi-automated identification of MPP is applied in combination with a multitemporal survey concept. Volume-reduced surface water samples were taken from transects at ten points along a major watercourse running through the South of Berlin, Germany, on six dates. After laboratory treatment, the samples were filtered onto glass fiber filters, scanned with an imaging spectrometer and analyzed by image processing.The presented method allows to count MPP, classify the plastic types and determine particle sizes. At the present stage of development particles larger than 450 μm in diameter can be identified and a visual validation showed that the results are reliable after a subsequent visual final check of certain typical error types. Therefore, the method has the potential to accelerate microplastic identification by complementing FTIR and Raman microspectroscopy. Technical advancements (e.g. new lens) will allow lower detection limits and a higher grade of automatization in the near future.The resulting microplastic concentrations in the water samples are discussed in a spatio-temporal context with respect to the influence (i) of urban areas, (ii) of effluents of three major Berlin wastewater treatment plants discharging into the canal and (iii) of precipitation events. Microplastic concentrations were higher downstream of the urban area and after precipitation. An increase in microplastic concentrations was discernible for the wastewater treatment plant located furthest upstream though not for the other two.

Few studies have analyzed the health effects of temperature variability (TV) accounting for both interday and intraday variations in ambient temperature. In this study, TV was defined as the standard deviations of the daily minimum and maximum temperature during different exposure days. Distributed lag non-linear Poisson regression model was used to examine the city-specific effect of TV on mortality in 31 Chinese municipalities and provincial capital cities. The national estimate was pooled through a meta-analysis based on the restricted maximum likelihood estimation. To assess effect modification on TV-mortality association by individual characteristics, stratified analyses were further fitted. Potential effect modification by city characteristics was performed through a meta-regression analysis. In total, 259 million permanent residents and 4,481,090 non-accidental deaths were covered in this study. The effect estimates of TV on mortality were generally increased by longer exposure days. A 1 °C increase in TV at 0–7 days' exposure was associated with a 0.60% (95% CI: 0.25–0.94%), 0.65% (0.24–1.05%), 0.82% (0.29–1.36%), 0.86% (0.42–1.31%), 0.98% (0.57–1.39%) and 0.54% (−0.11-1.20%) increase in non-accidental, cardiovascular, IHD, stroke, respiratory and COPD mortalities, respectively. Those with lower levels of educational attainment were significantly susceptible to TV. Cities with dense population, higher mean temperatures, and relative humidity and lower diurnal temperature ranges also had higher mortality risks caused by TV. This study demonstrated that TV had considerable health effects. An early warning system to alert residents about large temperature variations is recommended, which may have a significant impact on the community awareness and public health.

Benzylalkyldimethylethyl ammonium compounds are pervasive in natural environments and toxic at high concentrations. The changes in functional genes and microbial diversity in eutrophic lake samples exposed to benzyldimethyldodecyl ammonium chloride (BAC) were assessed. BAC exerted negative effects on bacteria abundance, particularly at concentrations of 100 μg L−1 and higher. A significant increase in the number of the quaternary ammonium compound-resistant gene qacA/B was recorded within the 10 μg L−1 treatment after the first day of exposure. Not all antibiotic resistance genes increased in abundance as the concentrations of BAC increased; rather, gene abundances were dependent on the gene type, concentrations of BAC, and contact time. The nitrogen fixation-related gene nifH and ammonia monooxygenase gene amoA were inhibited by high concentrations of BAC after the first day, whereas an increase of the nitrite reductase gene nirK was stimulated by exposure. Microbial communities within higher treatment levels (1000 and 10 000 μg L−1) exhibited significantly different community composition compared to other treatment levels and the control. Selective enrichment of Rheinheimera, Pseudomonas, and Vogesella were found in the higher treatment levels, suggesting that these bacteria have some resistance or degradation capacity to BAC. Genes related with RNA processing and modification, transcription, lipid transport and metabolism, amino acid transport and metabolism, and cell motility of microbial community function were involved in the process exposed to the BAC stress.

Compacted clay is widely used as capillary barriers in landfill final cover system. Recently, biochar amended clay (BAC) has been proposed as a sustainable alternative cover material. However, the effects of biochar on saturated hydraulic conductivity (kₛₐₜ) of clay with high degree of compaction is not yet understood. The present study aims to investigate the effects of biochar on kₛₐₜ of compacted kaolin clay. Soil specimens were prepared by amending kaolin clay with biochar derived from peanut-shell at 0, 5 and 20% (w/w). The kₛₐₜ of soil specimens was measured using a flexible water permeameter. The effects of biochar on the microstructure of the compacted clay was also investigated using MIP. Adding 5% and 20% of biochar increased the kₛₐₜ of compacted kaolin clay from 1.2 × 10⁻⁹ to 2.1 × 10⁻⁹ and 1.3 × 10⁻⁸ ms⁻¹, respectively. The increase in kₛₐₜ of clay was due to the shift in pore size distribution of compacted biochar-amended clay (BAC). MIP results revealed that adding 20% of biochar shifted the dominant pore diameter of clay from 0.01–0.1 μm (meso– and macropores) to 0.1–4 μm (macropores). Results reported in this communication revealed that biochar application increased the kₛₐₜ of compacted clay, and the increment was positively correlated to the biochar percentage.

Polycyclic aromatic hydrocarbons (PAHs) are environmental endocrine disruptors, which may modify the bone mineralization. However, epidemiological evidences on this issue were scant. We aimed to investigate the associations of PAHs with bone mass density (BMD) and osteoporosis based on a nationally-representative sample from general U.S. population. Data utilized were extracted from the 2005–2010 National Health and Nutrition Examination Survey (NHANES). Nine urinary PAHs (U-PAHs) metabolites were measured as exposure biomarkers. Associations of specific U-PAHs with BMD and osteoporosis were estimated by multivariable adjusted linear regression models and logistic regression models, respectively. Compared with women at the first tertiles, those at the third tertiles of 1-Hydroxynapthalene, 2-Hydroxyfluorene, 3-Hydroxyphenanthrene, 2-Hydroxyphenanthrene and 9-Hydroxyfluorene had significantly decreased BMD levels [coefficient (β) = −0.023 to −0.014, p < 0.05] or increased likelihoods of osteoporosis [odds ratios (ORs) = 1.86 to 3.36, p < 0.05] at different bone sites. Whereas, elevated BMD levels (β = 0.021, p < 0.05) at trochanter and decreased likelihoods of osteoporosis (OR = 0.33, p < 0.05) at intertrochanter were observed among women at the second tertiles of 1-Hydroxypyrene and 2-Hydroxynapthalene, respectively. Similar results were found for all the population, i.e., combination of men and women. Most of the significant associations disappeared among adult men only. Furthermore, Associations between U-PAHs and BMD were stronger for postmenopausal women when compared with premenopausal group. In conclusion, associations of U-PAHs with BMD and osteoporosis varied by specific U-PAHs and bone sites, as well as menopausal status and genders in U.S. adults.