Particulate matter (PM), which are chemically and biochemically complicated particles, accommodate a plethora of microorganisms. In the present study, we report the influence of heavy metal pollution on the abundance and community structure of archaea and bacteria associated with PM samples collected from polluted and non-polluted regions of Cochin Estuary (CE), Southwest coast of India. We observed an accumulation of heavy metals in PM collected from CE, and their concentrations were in the order Fe > Zn > Mn > Cr > Pb > Cu > Cd > Co > Ni. Zinc was a major pollutant in the water (4.36–130.50 μgL⁻¹) and in the particulate matter (765.5–8451.28 μgg⁻¹). Heavy metals, Cd, Co, and Pb were recorded in the particulate matter, although they were below detectable limits in the water column. Statistical analysis showed a positive influence of particulate organic carbon, nitrogen, PM-Pb, PM-Zn and PM-Fe on the abundance of PM-archaea and PM-bacteria. The abundance of archaea and bacteria were ten times less in PM compared with planktonic ones. The abundance of PM-archaea ranged between 4.27 and 9.50 × 10⁷and 2.73 to 3.85 × 10⁷ cellsL⁻¹ respectively for the wet and dry season, while that of PM-bacteria was between 1.14 and 6.72 × 10⁸ cellsL⁻¹ for both seasons. Community structure of PM-bacteria varied between polluted and non-polluted stations, while their abundance does not show a drastic difference. This could be attributed to the selective enrichment of bacteria by heavy metals in PM. Such enrichment may only promote the growth of metal resistant archaea and bacteria, which may not participate in the processing of PM. In such cases, the PM may remain without remineralization in the system arresting the food web dynamics and biogeochemical cycles.

Human external exposure (i.e. intake) of organophosphate flame retardants (PFRs) has recently been quantified, but no link has yet been established between external and internal exposure. In this study, we used a pharmacokinetic (PK) model to probe the relationship between external and internal exposure data for three PFRs (EHDPHP, TNBP and TPHP) available for a Norwegian cohort of 61 individuals from 61 different households. Using current literature on metabolism of PFRs, we predicted the metabolite serum/urine concentrations and compared it to measured data from the study population. Unavailable parameters were estimated using a model fitting approach (least squares method) after assigning reasonable constraints on the ranges of fitted parameters. Results showed an acceptable comparison between PK model estimates and measurements (<10-fold deviation) for EHDPHP. However, a deviation of 10–1000 was observed between PK model estimates and measurements for TNBP and TPHP. Sensitivity and uncertainty analysis on the PK model revealed that EHDPHP results showed higher uncertainty than TNBP or TPHP. However, there are indications that (1) current biomarkers of exposure (i.e. assumed metabolites) for TNBP and TPHP chemicals might not be specific and ultimately affecting the outcome of the modeling and (2) some exposure pathways might be missing. Further research, such as in vivo laboratory metabolism experiments of PFRs including identification of better biomarkers will reduce uncertainties in human exposure assessment.

White rot fungi have been proved to be a promising option for the removal of heavy metals, understanding their toxic response to heavy metals is conducive to developing and popularizing fungi-based remediation technologies so as to lessen the hazard of heavy metals. In this study, Cr(VI)-induced oxidative stress and apoptosis in Pycnoporus sanguineus, a species of white rot fungi were investigated. The results suggested that high level of Cr(VI) promoted the formation of ROS, including H2O2, O2•− and ·OH. With the increment of Cr(VI) concentration, the SOD and CAT activity along with GSH content increased within the first 24 h, but decreased afterwards, companied with a significant enhancement of MDA content. Cr(VI)-induced oxidative damage further caused and aggravated apoptosis in Pycnoporus sanguineus, especially at Cr(VI) concentrations above 20 mg/L. Cr(VI)-induced apoptosis was involved with mitochondrial dysfunction including mitochondrial depolarization, the enhancement of mitochondrial permeability and release of cytochrome c. The early and late apoptosis hallmarks, such as metacaspase activation, phosphatidylserine (PS) externalization, DNA fragmentation and the nuclear condensation and fragmentation were observed. Moreover, we also found disturbances of ion homeostasis, which was featured by K+ effluxes and overload of cytoplasmic and mitochondrial Ca2+.Based on these results, we suggest that Cr(VI) induced oxidative stress and apoptosis in white rot fungi, Pycnoporus sanguineus.

The toxicity of oil sands process-affected water (OSPW) has been primarily attributed to polar organic constituents, including naphthenic acid fraction components (NAFCs). Our objective was to assess the toxicity of NAFCs derived from fresh and aged OSPW, as well as commercial naphthenic acid (NA) mixtures. Exposures were conducted with three aquatic species: Hyalella azteca (freshwater amphipod), Vibrio fischeri (marine bacterium, Microtox® assay), and Lampsilis cardium (freshwater mussel larvae (glochidia)). Commercial NAs were more toxic than NAFCs, with differences of up to 30-, 4-, and 120-fold for H. azteca, V. fischeri, and L. cardium, respectively, demonstrating that commercial NAs are not reliable surrogates for assessing the toxicity of NAFCs. Differences in toxicity between species were striking for both commercial NAs and NAFCs. Overall, V. fischeri was the least sensitive and H. azteca was the most sensitive organism. Responses of V. fischeri and H. azteca to NAFC exposures were consistent (< 2-fold difference) regardless of source and age of OSPW; however, effects on L. cardium ranged 17-fold between NAFCs. NAFCs derived from fresh OSPW sources were similarly or less toxic to those from aged OSPW. Our results support the need to better characterize the complex mixtures associated with bitumen-influenced waters, both chemically and toxicologically.

A prospective cohort study of a Chinese population of mother–neonate pairs (n = 3103) was conducted to investigate the relationship between the cumulative hazard index (HI) of combined diethyl phthalate (DEP), dibutyl phthalate (DBP), dibenzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) exposure and birth outcomes. The estimated HI for phthalates was based on phthalate metabolite concentrations in urine collected between 5th and 14th gestational weeks. The median HI values according to the European Food Safety Authority tolerable daily intake (HITDI) and U.S. Environmental Protection Agency reference dose (HIRfD) were 0.358 and 0.187, respectively. A total of 16.3% and 1.9% of the women exhibited HITDI and HIRfD exceeding the value of one, respectively. In unadjusted models, the categories (low < P25, median P25–P50, high > P75) of HITDI were associated with decreased birth weight (β = −26.34 g, p = 0.021) and head circumference (β = −0.09 cm, p = 0.029), whereas those for HIRfD were negatively associated with birth weight (β = −31.74 g, p = 0.005), birth length (β = −0.11 cm, p = 0.032), head circumference (β = −0.13 cm, p = 0.003) and chest circumference (β = −0.10 cm, p = 0.021) in all neonates. Adjustment for potential confounders revealed that HIRfD was inversely associated with head circumference (β = −0.10 cm, p = 0.020). Stratification by gender indicated that HIRfD was associated with decreased birth length (β = −0.17 cm, p = 0.041) in infant boys and HITDI was associated with decreased birth weight (β = −33.12 g, p = 0.036) and head circumference (β = −0.13 cm, p = 0.027) in girls. This is the first study on the cumulative risk assessment of phthalate exposures in pregnant Chinese women. We found that the HI values of multiple phthalate co-exposure were sex-specifically related to birth outcomes.

This paper presents an extension of our previous wind-tunnel study (Nosek et al., 2016) in which we highlighted the need for investigation of the removal mechanisms of traffic pollution from all openings of a 3D street canyon. The extension represents the pollution flux (turbulent and advective) measurements at the lateral openings of three different 3D street canyons for the winds perpendicular and oblique to the along-canyon axis. The pollution was simulated by emitting a passive gas (ethane) from a homogeneous ground-level line source positioned along the centreline of the investigated street canyons. The street canyons were formed by courtyard-type buildings of two different regular urban-array models. The first model has a uniform building roof height, while the second model has a non-uniform roof height along each building's wall. The mean flow and concentration fields at the canyons' lateral openings confirm the findings of other studies that the buildings' roof-height variability at the intersections plays an important role in the dispersion of the traffic pollutants within the canyons. For the perpendicular wind, the non-uniform roof-height canyon appreciably removes or entrains the pollutant through its lateral openings, contrary to the uniform canyon, where the pollutant was removed primarily through the top. The analysis of the turbulent mass transport revealed that the coherent flow structures of the lateral momentum transport correlate with the ventilation processes at the lateral openings of all studied canyons. These flow structures coincide at the same areas and hence simultaneously transport the pollutant in opposite directions.

Extreme weather events are major drivers of ecological change, and their occurrence is likely to increase due to climate change. The transient increases in atmospheric temperatures are leading to a greater occurrence of heat waves, extreme events that can produce a substantial warming of water, especially in enclosed basins such as the Mediterranean Sea. Here, we tested the effects of current and predicted heat waves on the early stages of development of the seagrass Posidonia oceanica. Temperatures above 27 °C limited the growth of the plant by inhibiting its photosynthetic system. It suffered a reduction in leaf growth and faster leaf senescence, and in some cases mortality. This study demonstrates that the greater frequency of heat waves, along with anticipated temperature rises in coming decades, are expected to negatively affect the germination of P. oceanica seedlings.

Transport of coal by train through residential neighborhoods in Metro Vancouver, British Columbia, Canada may increase the possibility of exposure to particulate matter at different size ranges, with concomitant potential negative health impacts. This pilot study identifies and quantifies train impacts on particulate matter (PM) concentrations at a single location. Field work was conducted during August and September 2014, with the attributes of a subset of passing trains confirmed visually, and the majority of passages identified with audio data. In addition to fixed ground based monitors at distances 15 and 50 m from the train tracks, an horizontally pointing mini-micropulse lidar system was deployed on three days to make backscatter and depolarization measurements in an attempt to identify the zone of influence, and sources, of train-generated PM. Ancillary wind and dust fall data were also utilized. Trains carrying coal are associated with a 5.3 (54%), 4.1 (33%), and 2.6 (17%) μgm−3 average increase in concentration over a 14 min period compared to the average concentrations over the 10 min prior to and after a train passage (“control” or “background” conditions), for PM3, PM10, and PM20, respectively. In addition, for PM10 and PM20, concentrations during train passages of non-coal-carrying trains were not found to be significantly different from PM concentrations during control conditions. Presence of coal dust particles at the site was confirmed by dust fall measurements. Although enhancements of PM concentrations during 14 min train passages were generally modest, passing coal trains occasionally enhanced concentrations at 50 m from the tracks by ∼100 μgm-3. Results showed that not every train passage increased PM concentrations, and the effect appears to be highly dependent on wind direction, local meteorology and load related factors. LiDAR imagery suggests that re-mobilization of track-side PM by train-induced turbulence may be a significant contributor to coarse particle enhancements.

Chlormadinone acetate (CMA) is a frequently used progestin with antiandrogenic activity in humans. Residues may enter the aquatic environment but potential adverse effects in fish are unknown. While the associated work focused on effects of CMA in vitro and in zebrafish eleuthero-embryos, the present study reports on reproductive and transcriptional effects in adult female and male zebrafish (Danio rerio).We performed a reproductive study using breeding groups of zebrafish. After 15 days of pre-exposure, we exposed zebrafish to different measured concentrations between 6.4 and 53,745 ng/L CMA for 21 days and counted produced eggs daily to determine fecundity. Additionally, transcriptional effects of CMA in brains, livers, and gonads were analyzed. CMA induced a slight but statistically not significant reduction in fecundity at 65 ng/L and 53,745 ng/L. Furthermore, we observed differential expression for gene transcripts of steroid hormone receptors, genes related to the hypothalamic-pituitary-gonadal axis, and steroidogenesis. In particular, we found significant decrease of transcript levels of vitellogenin (vtg1) in ovaries and liver, and of cyp2k7 in the liver of males, as well as a significant increase of transcripts of the progesterone receptor (pgr) in testes, and cyp2k1 in liver of females. The observed effects were weaker than those of other very potent progestins, which is probably related to the lack of interaction of CMA with the zebrafish progesterone receptor.

The increased use of pesticides has caused concern over the possible direct association of exposure to combinations of these compounds with bee health problems. There is growing proof that bees are regularly exposed to mixtures of agrochemicals, but most research has been focused on managed bees living in farmland, whereas little is known about exposure of wild bees, both in farmland and urban habitats. To determine exposure of wild bumblebees to pesticides in agricultural and urban environments through the season, specimens of five different species were collected from farms and ornamental urban gardens in three sampling periods. Five neonicotinoid insecticides, thirteen fungicides and a pesticide synergist were analysed in each of the specimens collected. In total, 61% of the 150 individuals tested had detectable levels of at least one of the compounds, with boscalid being the most frequently detected (35%), followed by tebuconazole (27%), spiroxamine (19%), carbendazim (11%), epoxiconazole (8%), imidacloprid (7%), metconazole (7%) and thiamethoxam (6%). Quantifiable concentrations ranged from 0.17 to 54.4 ng/g (bee body weight) for individual pesticides. From all the bees where pesticides were detected, the majority (71%) had more than one compound, with a maximum of seven pesticides detected in one specimen. Concentrations and detection frequencies were higher in bees collected from farmland compared to urban sites, and pesticide concentrations decreased through the season. Overall, our results show that wild bumblebees are exposed to multiple pesticides when foraging in agricultural and urban landscapes. Such mixtures are detected in bee tissues not just during the crop flowering period, but also later in the season. Therefore, contact with these combinations of active compounds might be more prolonged in time and widespread in the environment than previously assumed. These findings may help to direct future research and pesticide regulation strategies to promote the conservation of wild bee populations.