This work was carried to compare the efficiency of Cu and Al electrodes in the elimination of Yellow 10 gw dye solution with the optimization of operative factors such as pH, NaCl, contact time, and current density in the electrocoagulation method. Analysis of variance (ANOVA) was used to assess the impact of these variables, with significance set at P<0.05. The data was statistically examined with Origin2021 and SPSS software, and significant differences between mean values were determined using analysis of variance (ANOVA). For each experiment, duplicates were kept, and the efficiency of Yellow 10 gw dye solution for those parameters was derived using analysis at a 5% level of significance. The utility of treated dye solutions using both the electrodes was tested on V.radiata in terms of germination percentage, root, and shoot length with distilled water as control. For all of the qualities examined, significant disparities were found among entries. The dye solution used with Al resulted in much higher germination (100%), root length (9.72 cm), and shoot length (24.5 cm).

Pesticides are widely used to alleviate pest pressure in agricultural systems, and atrazine is a typical diffuse pollutant and serves a sensitivity index for environmental characteristics. Based on the physicochemical properties of parent substances, degradation products of pesticides may pose a greater threat to aquatic ecosystems than pesticides. Atrazine and three primary degradation products (deethylatrazine (DEA), deisopropylatrazine (DIA) and didealkylatrazine (DDA)) were investigated in a semienclosed bay of the western Pacific Ocean. Seasonal surface water and suspended particulate sediment (SPS) samples were collected from the estuary and bay in January, April, and August 2019. The level of pesticide contamination was lower in the bay than in the estuary, and the pesticide concentration in the dissolved phase was higher than that in the adsorbed phase. The average concentrations of atrazine and the three degradation products in the three seasons ranged from 2.42 to 328.46 ng/L in water and from 0.07 to 12.75 ng/L in SPS. The proportion of atrazine among the four detected pollutants decreased from 0.7 to 0.1 in surface water and from 0.3 to 0.1 in SPS over the seasons. As the main degradation products, the concentration proportions of DDA and DEA reached as high as 0.6 in August. The ratio of DEA to atrazine (DEA/ATR) increased from January to August, which indicated the progressive degradation process in the bay. Single-factor analysis of variance and principal component analysis indicated that atrazine degradation was sensitive to temperature, dissolved oxygen, and salinity. These three factors accounted for almost 70% of the seasonal variance in atrazine without a quantification assessment of photolysis or bacteria. The spatial distributions of DEA in the three seasons demonstrated that wind and currents also played important roles in pollutant redistribution. The seasonal temporal and spatial correlations between water and SPS demonstrated the degradation patterns of atrazine in marine conditions, supporting the need for future detailed toxicity studies.

In order to investigate the impacts of dam-related water impoundment on the spatial-temporal variations and transport of anthropogenic organic pollutants, 15 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed in water samples from the Shuikou Reservoir (SKR) of the Minjiang River. The SKR was formed after the construction of the Shuikou Dam, which is the largest hydropower station in Southeast China. The water samples were collected from the backwater zone of the SKR, in both the wet and dry seasons, corresponding to the drainage and impoundment periods of water flow, respectively. The concentrations of the dissolved PAHs in surface water from the wet season (average of 161 ± 97 ng L⁻¹) were significantly higher (ANOVA, p < 0.01) than those from the dry season (average of 43 ± 21 ng L⁻¹). PAH concentrations in the SKR decreased from upstream (industrialized cities) to downstream (rural towns or counties), indicating high PAH loads caused by intensive urbanization effects. The high proportions of 3-ring PAHs in the wet season were from local sources via surface runoff; while the elevated proportions of 4- to 6- ring PAHs in the dry season reflected atmospheric deposition emerged of these PAHs and/or volatilization of 3-ring PAHs enhanced. Molecular diagnostic ratios of PAH isomers in multimedium and principal component analysis indicated that PAH presence in the SKR was mainly attributed to pyrogenic origin. The isomeric ratios of fluoranthene to fluoranthene plus pyrene in the wet season were homogeneous, implying that there were continuous new inputs along the riverine runoff. However, these ratios showed spatial downward trend in the dry season, indicating continued degradation of PAHs occurred along the transport path during the impoundment period. The input and output fluxes of PAHs in the SKR were 5330 kg yr⁻¹ and 2991 kg yr⁻¹, revealing that the reservoir retained contaminants after impoundment of the hydropower dam.

In the last decade many studies have described the ingestion of plastic in marine animals. While most studies were dedicated to understanding the pre-ingestion processes involving decision-making foraging choices based on visual and olfactory cues of animals, our knowledge in the post-ingestion consequences remains limited. Here we proposed a theoretical complementary view of post-ingestion consequences, attempting to connect plastic ingestion with plastic-induced satiety. We analyzed data of plastic ingestion and dietary information of 223 immature green turtles (Chelonia mydas) from tropical Brazilian reefs in order to understand the impacts of plastic ingestion on foraging behavior. Generalized linear mixing models and permutational analysis of variance suggested that plastic accumulations in esophagus, stomach and intestine differed in their impact on green turtle’s food intake. At the initial stages of plastic ingestion, where the plastic still in the stomach, an increase in food intake was observed. The accumulation of plastic in the gastrointestinal tract can reduce food intake likely leading to plastic-induced satiety. Our results also suggest that higher amounts of plastics in the gastrointestinal tract may led to underweight and emaciated turtles. We hope that adopting and refining our proposed framework will help to clarify the post-ingestion consequences of plastic ingestion in wildlife.

Stormwater samples were collected from six different land use sites with three time-intervals during a precipitation event on August 12, 2016, from a community of Beijing, China. A total of 46 species volatile organic compounds (VOCs) were detected in these stormwater samples, including methyl tertiary-butyl ether (MTBE), aromatic hydrocarbons, halogenated aromatics, Halogenated alkanes, and alkenes. The total VOC concentrations varied in the six sites following order: highway junction > city road > gas station > park > campus > residential area, except for MTBE, which was much higher at gas station compared to other land use sites. ANOVA results indicated both land use and precipitation time intervals could significantly affect the VOC concentrations even in the small area. The Beijing atmospheric VOC concentrations were too low to explain the high concentrations in stormwater, suggesting that land surfaces may be the main sources of VOC other than the ambient atmosphere. MTBE and other VOCs correlation analysis indicated that MTBE mostly came from gasoline emissions, spills or vehicle exhausts, whereas the BTEX (benzene, toluene, ethylbenzene, Xylenes) and the halogenated aromatics were transferred from chemical plants through land surfaces accumulating and the wind blowing atmospheric VOCs. Xylenes/ethylbenzene (X/E) ratios variations indicated that stormwater incorporated larger amount of fresh emitted air during the precipitation event than prior to it. Information of these stormwater VOCs in this study could be used in the community pollution reduction strategies.

Microplastic (MP) vector effects have been well described in the literature but surprisingly little is in known about the impact of MPs on the intestinal uptake of contaminants. The present study aimed to determine whether the intestinal fate of Ag was affected by the presence of polyethylene MP beads. Ag (added as ¹¹⁰ᵐAg) was introduced into the lumen of rainbow trout (Oncorhynchus mykiss) anterior/mid-intestine gut sac preparations as Ag only, Ag and MPs (co-exposure) and Ag-incubated MPs (where Ag was adsorbed to the MP). Results show that after 3 h exposure the distribution of accumulated Ag between the four intestinal compartments (mucus layer, mucosal epithelium, muscle layer and serosal saline) was not affected by either MP condition when compared to Ag alone (p > 0.05, One way ANOVA). Across all treatment groups mucus layer binding dominated (54.2–72.6%) whereas relatively little Ag was transported to the blood compartment (i.e. combined muscle layer and serosal saline compartments, 8.5–15.0%). Accompanying adsorption/desorption studies were performed in relevant media. Over 24 h, 60.6± 2.9% of the available Ag in artificial freshwater adhered to the surface of the PE MPs. In pH adjusted luminal fluids (pH 2.2, 4.1, 7.4 and 9.8) that span the range of conditions encountered within the rainbow trout digestive tract, there was almost complete dissociation at acidic pHs within 3 h (<2% remaining on MPs at both pH 2.2 and pH 4.1). Such pHs are typical of piscine stomach. Based on our finding we suggest that following the ingestion of MPs with adsorbed pollutants, desorption would occur prior to entering the site of uptake. The MPs themselves have no impact on the trans-epithelial transport of the contaminant, but the net result of the MP vector effect is to potentially introduce labile contaminant forms into the intestine.

Air quality biomonitoring has been successfully assessed using mosses for decades in Europe, particularly regarding heavy metals (HM). Assessing robust temporal variations of HM concentrations in mosses requires to better understand to what extent they are affected by the sampling protocol and the moss species. This study used the concentrations of 14 elements measured during four surveys over 15 years in France. Analyses of variance (ANOVA) and a modeling approach were used to decipher temporal variations for each element and adjust them with parameters known to affect concentrations. ANOVA followed by post hoc analyses did not allow to estimate clear trends. A generalized additive mixed modeling approach including the sampling period, the collector and the moss species, plus quadratic effects, was used to analyze temporal variations on repeated sampling sites. This approach highlighted the importance of accounting for non-linear temporal variations in HM, and adjusting for confounding factors such as moss species, species-specific differences between sampling periods, collector and methodological differences in sampling campaigns. For instance, lead concentrations in mosses decreased between 1996 and 2011 following quadratic functions, with faster declines for the most contaminated sites in 1996. On the other hand, other HM showed double trends with U-shaped or hill-shaped curves. The effect of the moss was complex to handle and our results advocate for using one moss species by repeated site to better analyze temporal variations.

Polycyclic aromatic hydrocarbons (PAHs) are a category of over 100 various chemicals released from numerous combustion sources. The ubiquity and toxicity of PAHs have posed high health risks on human populations. This study aims to examine the long-term trends of atmospheric PAHs at the national-level in the U.S., and evaluate their cancer risks. Daily concentrations of PAHs measured at 169 monitoring stations between 1990 and 2014 were obtained from the U.S. Environmental Protection Agency's Air Quality System. Temporal trends were examined using generalized linear model with generalized estimating equations. Random-effects analysis of variance was performed to explore variance between regions, sites, years, and months with a hierarchical structure. Source categories were identified using diagnostic ratios. National population level cancer risks were estimated using the relative potency factors and inhalation unit risk method. Ambient PAH concentrations displayed an overall downward trend (6–9% annual reduction) in urban areas, but not in rural areas. Seasonal and weekday/weekend effects were significant. Urban concentrations were twice of the rural level. The between-site variation outweighed the temporal variation, indicating large spatial heterogeneity. The predominant PAH sources were from traffic and non-traffic related fuel combustions with a dominant contribution from diesel emissions. The average excess lifetime cancer risk was estimated to be 9.3 ± 30.1 × 10−6 (GM: 4.2 × 10−6) from exposure to ten carcinogenic PAHs. This is the first comprehensive study of the spatiotemporal trends of ambient PAHs at the U.S. national level. The results indicate that future efforts aimed to reduce PAH exposures should focus on diesel emission controls and extending the geographic coverage of air monitoring.

The aim of the study was to estimate the influence of the 2,4-dichlorophenoxy acetic acid and 2-methyl-4-chlorophenoxyacetic acid on the uptake and translocation of Cd, Co, Ni, Cu, Zn, Pb and Mn by wheat (Triticum aestivum L.). Two farmland soils typical for the central Polish rural environment were used. Studies involved soil analyses, contents of bioavailable, exchangeable and total forms for all investigated metals. Atomic absorption spectrometry was used to determine the concentration of the elements. The best correlation between the herbicide rate and the metal concentration was visibly for the underground part of plants. Analysis of variance proved that herbicide treatment of wheat frequently influences the metal transfer from soil and their concentration in roots and shoots. In particular, higher herbicide rates prompted the significant increase of all metals concentration in roots. Additionally, transfer coefficients depended on the type of soil and the herbicide rate applied. Uptake of metals may be also influenced by the formation of sparingly water-soluble metal-herbicide complexes. Its intensity would then depend on the solubility of particular chemical entity with the low solvable Pb, Cu and Cd complexes being the least mobile.

We evaluated the occurrence of 12 veterinary antibiotics and a beta agonist over spatial and temporal scales in Shell Creek, an intensively agricultural watershed in Nebraska, using Polar Organic Chemical Integrative Samplers (POCIS). Twelve pharmaceuticals were detected with concentrations ranging from 0.0003 ng/L to 68 ng/L. The antibiotics measured at the highest time-weighted average concentrations were lincomycin (68 ng/L) and monensin (49 ng/L), and both compounds were detected at increased concentrations in summer months. Analysis of variance indicates that mean concentrations of detected pharmaceuticals have no significant (p > 0.01) spatial variation. However, significant temporal differences (p < 0.01) were observed. This study demonstrates the utility of passive samplers such as POCIS for monitoring ambient levels of pharmaceuticals in surface waters.