Palladium (Pd) emitted from vehicles equipped with exhaust catalytic converters has been accumulating at a greater rate relative to other platinum group elements (PGE) in the last 10–20 years. Little is known, however, regarding the various environmental factors and conditions which are likely to modulate the chemical behavior and bioaccessibility of this element post-emission. To meet data needs, soils and a Pd model substance were treated with solutions containing common anions (Cl−, NO3−, SO42− und PO43−) to shed light on the geochemical behavior of emitted Pd under ambient conditions. As part of this, the particle surface chemistry of treated residues (insoluble phase) and solutions (soluble phase) was examined using XPS to assess the chemical transformation of Pd in the presence of inorganic anions. The results show that Pd is the most soluble in the presence of anionic species, followed by rhodium (Rh) and platinum (Pt). Pd in field-collected samples was found to be considerably more soluble than the metallic Pd in the model substance, Pd black, when treated with anionic species. The results also demonstrate that the solubility of Pd black is strongly dependent on solution pH, concentration and the duration of reaction. The outer 3–4 atomic layers of metallic Pd was determined via XPS to be partially oxidized when treated with anion solutions, with the degree being dependent on anion type. The concentration of dissolved O2 in solution was found to have little impact on the transformation of metallic Pd. Given the ubiquitous nature of the anions examined, we can expect that Pd will become more bioaccessible post-emission.

There are limited ambient air measurements of extended (beyond EPA Priority 16) lists of polycyclic aromatic hydrocarbons (PAHs). We measured air concentrations of 45 PAHs using passive and active air sampling at 15 sites in a central urban community and one rural site for two years. Passive sampling was conducted with cylindrical XAD-based samplers deployed to capture spatial variability. High volume active samplers with quartz fiber filters for particles and XAD-4 absorbent for gases were deployed at two urban sites and the rural site to calibrate the passive measurements directly. Estimated passive sampling rates (PSRs) were evaluated as functions of meteorological data, seasons, locations, study year, and compared with other studies. Possible particle collection by the passive samplers was evaluated using a variety of particle measurements (TSP, PM10, PM2.5 and ultrafines <100 nm). Total PAHs were statistically associated with ultrafine particle concentrations and to a lesser extent PM2.5 and PM10, but not TSP. PSRs were more variable when PAH mass loadings were lower and near method detection limits; this occurred more often at the rural site. The PSRs were not statistically associated with meteorological conditions in this study, but wind speed had the highest potential to impact PSR results. The resulting passive PAH measurements are reported with respect to proximity to major roadways and other known air emissions types. PSRs were quantifiable for some PAHs that were found predominantly in the particulate phase in active sampling. This information, together with particle fraction calculations from active sampling, were used to estimate the particulate PAH capture of the passive sampler. Summed PAH (∑PAH) passive concentrations were measured within the range of 10–265 ng/m3, with the highest concentrations from naphthalene and the lowest detected concentrations from anthracene. These results indicated a stronger seasonal signal within 200 m of a major roadway.

The present study aimed to investigate biodegradation mechanisms of black carbon (BC)-bound contaminants in BC-amended sediment when BC was applied to control organic pollution. The single-point Tenax desorption technique was applied to track the species changes of nonylphenol (NP) during biodegradation process in the rice straw carbon (RC)-amended sediment. And the correlation between the biodegradation and desorption of NP was analyzed. Results showed that microorganisms firstly degraded the rapid-desorbing NP (6 h Tenax desorption) in RC-amended sediment. The biodegradation facilitated the desorption of slow-desorbing NP, which was subsequently degraded as well (192 h Tenax desorption). Notably, the final amount of NP degradation was greater than that of NP desorption, indicating that absorbed NP by RC amendment can be degraded by microorganisms. Finally, the residual NP amount in RC-amended sediment was decided by RC content and its physicochemical property. Moreover, the presence of the biofilm was observed by the confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) so that microorganisms were able to overcome the mass transfer resistance and directly utilized the absorbed NP. Therefore, single-point Tenax desorption alone may not be an adequate basis for the prediction of the bioaccessibility of contaminants to microorganisms or bioremediation potential in BC-amended sediment.

This study aimed to evaluate the adverse effects of the insecticide imidacloprid (IMI) on male spermatogenesis, steroidogenesis, and DNA damage in sexually mature and immature rats. Forty male rats (mature and immature) were equally divided into four groups: two mature and two immature groups. IMI groups of both ages were orally administered IMI in corn oil at a concentration of 1 mg/mL for kg BW/day, whereas their respective controls were orally administered corn oil only (1 mL/kg of body weight) daily for 65 days. On day 66, the rats were lightly anesthetized and then euthanized by cervical dislocation. Whole blood was collected for hemogram, serum for hormonal profile, semen for sperm profile, and testes for gene expression and histopathological, and immunohistochemical examinations. The obtained results revealed that both sexually mature and immature rats orally exposed to IMI showed serious abnormalities in sperm morphology and concentrations, with an imbalance of sexual hormones. There were increases in the level of serum 8-hydroxy-2′-deoxyguanosine and in the percentage of comet (tailed) sperm DNA in the IMI-treated groups. The results exhibited the upregulation of a DNA damage tolerance gene (8-oxoguanine glycosylase 1) and downregulation of the activity of steroidogenic genes (nuclear receptor subfamily 5, group A, member 1 and 3β-hydroxysteroid dehydrogenase). Immunohistochemical examination of the B-cell lymphoma 2-associated X apoptotic protein in testicular sections showed various degrees of apoptosis in the spermatogonial cells of the IMI-treated rats compared to the control groups. These damaging effects of IMI were more pronounced in the sexually mature rats than in the immature rats. In conclusion, despite using a low dose of IMI in the present study, there were noticeable harmful consequences on the reproductive system at different stages of sexual maturity in male rats.

Walleye (Sander vitreus) are a commercially important North American fish species that inhabit the Athabasca River. This river flows through the Athabasca oil sands where natural sources of bitumen erode from the McMurray formation. Little information is available on responses of walleye embryos to oil sands tailings pond sediments in a laboratory setting. The current study describes the design and implementation of a daily-renewal bioassay to assess the potential effects of tailings pond sediments from the Athabasca oil sands area on walleye development. Developing walleye embryos were exposed to increasing concentrations of two tailings pond sediments (collected in the Athabasca oil sands area) until the completion of yolk absorption in control fish. Sediments from the tailings pond represent a mixture of polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs. During the 31 day exposure, the walleye were examined for mortalities, weight, length and developmental abnormalities to provide an initial evaluation of the effects of the oil sands tailings pond sediments. Walleye embryo survival differed between the tailings pond sediments, and survival decreased with increasing sediment concentration. Alkylated PAH content differed between the two tailings pond sediments and lower embryo survival corresponded to higher total and alkylated PAH content. Tailings pond sediment-exposed walleye exhibited a delay in development, as well as increased percentages of larvae with heart and yolk sac edema, and cranial and spinal malformations. These abnormalities in development are often associated with PAH and alkylated PAH exposure. This study provides an exposure design that can be used to assess sediment toxicity to early developmental stages of a fish species not commonly tested in the lab, and lays the groundwork for future studies with this and other difficult-to-culture species. These results offer information on the potential effects of tailings pond sediments containing PAH/alkylated PAH mixtures on walleye development and survival.

In this study water balance components as well as nitrogen and dissolved organic carbon leaching were quantified by means of large weighable grassland lysimeters at three sites (860, 770 and 600 m a.s.l.) for both intensive and extensive management. Our results show that at E600, the site with highest air temperature (8.6 °C) and lowest precipitation (981.9 mm), evapotranspiration losses were 100.7 mm higher as at the site (E860) with lowest mean annual air temperature (6.5 °C) and highest precipitation (1359.3 mm). Seepage water formation was substantially lower at E600 (−440.9 mm) as compared to E860. Compared to climate, impacts of management on water balance components were negligible. However, intensive management significantly increased total nitrogen leaching rates across sites as compared to extensive management from 2.6 kg N ha−1 year−1 (range: 0.5–6.0 kg N ha−1 year−1) to 4.8 kg N ha−1 year−1 (range: 0.9–12.9 kg N ha−1 year−1). N leaching losses were dominated by nitrate (64.7%) and less by ammonium (14.6%) and DON (20.7%). The low rates of N leaching (0.8–6.9% of total applied N) suggest a highly efficient nitrogen uptake by plants as measured by plant total N content at harvest. Moreover, plant uptake was often exceeding slurry application rates, suggesting further supply of N due to soil organic matter decomposition. The low risk of nitrate losses via leaching and surface runoff of cut grassland on non-sandy soils with vigorous grass growth may call for a careful site and region specific re-evaluation of fixed limits of N fertilization rates as defined by e.g. the German Fertilizer Ordinance following requirements set by the European Water Framework and Nitrates Directive.

Microcystin-leucine arginine (MC-LR) causes testicular inflammation and hinders spermatogenesis. However, the molecular mechanisms underlying the immune responses to MC-LR in the testis have not been elucidated in detail. In this study, we show that MC-LR induced immune responses in Sertoli cells (SC), germ cells (GC), and Leydig cells (LC) via activating phosphatidylinositol 3-kinase (PI3K)/AKT/nuclear factor kappa B (NF-κB), resulting in the production of pro-inflammatory cytokines and chemokines including tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and chemokine (C-X-C motif) ligand 10 (CXCL10). The observed effects were attributed to reduced activity of protein phosphatases 2A (PP2A) as a result of binding of MC-LR to the catalytic subunit of PP2A in SC and GC. By contrast, innate immune responses were triggered by Toll-like receptor 2 (TLR2) in LC because MC-LR could not enter into the LC and subsequently inhibit the PP2A activity. PI3K/AKT/NF-κB were also activated in SC, GC, and LC in vivo, with the enrichment of TNF-α, IL-6, MCP-1, and CXCL10 in the testis. Following chronic exposure, MC-LR-treated mice exhibited decreased sperm counts and abnormal sperm morphology. Our data demonstrate that MC-LR can activate innate immune responses in testicular cells, which provides novel insights to explore the mechanism associated with MC-LR-induced orchitis.

Numerous studies have evaluated the effects of long-term exposure to ambient air pollution on hypertension. However, little information exists regarding its effects on prehypertension, a very common, but understudied cardiovascular indicator. We evaluated data from 24,845 adults (ages 18–74 years) living in three Northeastern Chinese cities in 2009. Blood pressure (BP) was measured by trained observers using a standardized mercuric-column sphygmomanometer. Three-year (from 2006 to 2008) average concentrations of particles with an aerodynamic diameter ≤10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and ozone (O3) were calculated using data from monitoring stations. Effects were analyzed using generalized additive models and two-level regression analyses, controlling for covariates. We found positive associations of all pollutants with prehypertension (e.g. odds ratio (OR) was 1.17 (95% confidence interval (CI), 1.09–1.25) per interquartile range (IQR) of PM10) in a fully adjusted model, as compared to normotensive participants. These associations were stronger than associations with hypertension (e.g. OR was 1.03 (95% CI, 1.00, 1.07) per IQR of PM10). We have also found positive associations of all studied pollutants with systolic and diastolic BP: e.g., associations with PM10 per IQR were 1.24 mmHg (95% CI, 1.03–1.45) for systolic BP and 0.47 mmHg (95% CI, 0.33–0.61) for diastolic BP. Further, we observed that associations with BP were stronger in women and in older participants (systolic BP only). In conclusion, long-term exposure to ambient air pollution was more strongly associated with prehypertension than with hypertension, especially among females and the elderly. Thus, interventions to reduce air pollution are of great significance for preventing future cardiovascular events, particularly among individuals with prehypertension.

Trifluoroacetic acid (TFA) in the atmosphere is produced by degradation of hydrochlorofluorocarbons and hydrofluorocarbons. In recent years, TFA has attracted global attention because of increased environmental concentrations, biological toxicity and accumulation in aqueous environments. This study focused on the mechanisms underlying the adsorption of TFA by particulate matter to identify the appropriate descriptive model for this process and thus improve estimation of TFA adsorption in future environmental monitoring. Onsite gas and particle phase sampling in Beijing, China, and subsequent measurement of TFA concentrations indicated that the TFA concentration in the gas phase (1396 ± 225 pg m−3) was much higher than that in the particle phase (62 ± 8 pg m−3) and that monthly concentrations varied seasonally with temperature. Based on the field results and analysis, an adsorption experiment of TFA on soot was then conducted at three different temperatures (293, 303, and 313 K) to provide parameters for kinetic and thermodynamic modelling. The proportion of atmospheric TFA concentration in the gas phase increased with temperature, indicating that temperature affected the phase distribution of TFA. The subsequent kinetic and thermodynamic modelling showed that the adsorption of TFA by soot could be described well by the Bangham kinetic model. The adsorption was controlled by diffusion, and the key mechanism was physical adsorption. The adsorption behavior can be well described by the Langmuir isotherm model. The calculated thermodynamic parameters ΔG° (−2.34, −1.25, and −0.15 kJ mol−1 at 293, 303, and 313 K, respectively), ΔH° (−34.34 kJ mol−1), and ΔS° (−109.22 J mol−1 K−1) for TFA adsorption by soot were negative, indicating that adsorption was a spontaneous, exothermic process.

In agricultural lowland landscapes, intensive agricultural is accompanied by a wide use of agrochemical application, like pesticides and fertilizers. The latter often causes serious environmental threats such as N compounds leaching and surface water eutrophication; additionally, since perchlorate can be present as impurities in many fertilizers, the potential presence of perchlorates and their by-products like chlorates and chlorites in shallow groundwater could be a reason of concern. In this light, the present manuscript reports the first temporal and spatial variation of chlorates, chlorites and major anions concentrations in the shallow unconfined aquifer belonging to Ferrara province (in the Po River plain). The study was made in 56 different locations to obtain insight on groundwater chemical composition and its sediment matrix interactions.During the monitoring period from 2010 to 2011, in June 2011 a nonpoint pollution of chlorates was found in the shallow unconfined aquifer belonging to Ferrara province. Detected chlorates concentrations ranged between 0.01 and 38 mg/l with an average value of 2.9 mg/l. Chlorates were found in 49 wells out of 56 and in all types of lithology constituting the shallow aquifer. Chlorates concentrations appeared to be linked to NO3−, volatile fatty acids (VFA) and oxygen reduction potential (ORP) variations. Chlorates behaviour was related to the biodegradation of perchlorates, since perchlorates are favourable electron acceptors for the oxidation of labile dissolved organic carbon (DOC) in groundwater. Further studies must take into consideration to monitor ClO4− in pore waters and groundwater to better elucidate the mass flux of ClO4− in shallow aquifers belonging to agricultural landscapes.