Dechlorane plus (DP) is a chlorinated flame retardant with high production volume (HPV) and is widely used in our daily necessities. In the present study, a laboratory-scale microcosm was built up to simulate the uptake, depuration, bioaccumulation, and stereoselective enrichment of DP in a lower concentration and equilibration condition. Common carp (Cyprinus carpio) were used for 32 days exposure and 32 days depuration. The concentration ratios of syn-DP to total DP (fₛyₙ values) in fish examined were lower than that in commercial products. Rate constants of uptake (kS) and elimination (kₑ) for the syn- and anti-DP were calculated using a first-order kinetic model. The uptake rate constants of syn- and anti-DP were 0.63 and 0.89 day⁻¹, respectively. The depuration rate constants of syn-DP (0.11 day⁻¹) were similar to anti-DP (0.096 day⁻¹), suggesting that anti-DP is absorbed faster than syn-DP by common carp. The estimated bioconcentration factors for both syn-DP (5700 L/kg) and anti-DP (9300 L/kg) were higher than the bioconcentration hazard criteria outlined in the Stockholm Convention, suggesting the bioconcentration potential to aquatic organisms for DP.

Anthropogenic disturbance of coastal ecosystems has increased the need for comprehensive methods and indicators to assess the health status of marine ecosystems. Biotic indices are important as they indicate different ecological states. In this study, Eco-Exergy-based indices (Exergy and Structural Exergy) and diversity indices (Shannon–Wiener index and Margalef index) were applied in the seas around the Zhoushan archipelago, and correlation analysis between biotic indices and environmental factors was used to test the robustness of these indices in capturing the environment changes, aimed to provide reference in selecting the indices for assessing marine eco-environment quality. Results showed that the benthic indices of Exergy, Shannon–Wiener, and Margalef increased with the distance from the mainland. The Eco-Exergy-based indices and Margalef index were significantly, negatively correlated with dissolved inorganic nitrogen and reactive phosphate, and significantly, positively correlated with the salinity of seawater. Overall, the marine ecosystem was more stable further away from the coast, where salinity was higher, and pollutants such as nutrients in seawater were lower. In addition, biodiversity and Eco-Exergy was also higher. Generally, Eco-Exergy-based indices were observed to be good indicators for detecting the environment changes in the study area.

Naturally occurring radioactive materials (NORMs) and the presence of toxic metals in drilling fluids/their additives have raised research interests in recent times owing to the risks associated with the exposure times for drillers of petroleum wells. In this study, two drilling fluids A and B were formulated, while two other Mud Samples C and D were obtained from drilled shale and shale-sand formation zones. All four fluids were collected and analyzed for the presence of radioactive and heavy metals. Lead (Pb), mercury (Hg), cadmium Cd), zinc (Zn), chromium (Cr), aluminum (Al), arsenic (As), nickel (Ni), and copper (Cu) were detected in the mud samples. The heavy metal contents of the mud samples are in the following decreasing order of magnitude Hg > Pb > Cd > Cr. In Samples A–D, Hg, Pb, Cr, and Cd were found to have significant concentrations, and the concentrations of these metals increased in the mud samples after they were used for drilling. The concentration of Hg was above the permissible limit. Also, the concentrations of Pb, Cu, As, and Al found in Mud Samples A and B can cause skin irritations over long-term exposures, while Cd, Hg, Zn, and Ni present in the samples were within levels that can cause lung infections or immune breakdown when ingested over long periods. The quantities of Cd, Hg, and Cu detected in Mud Samples C and D can cause skin irritations over long-term exposures, while those of As, Zn, Ni, and Al were seen to have the potential to cause dermal infections/diseases. Based on the results obtained, the cancer risk for the drilling crew lies within 1.1 × 10⁻³ - 7.7 × 10⁻³ HQ. The highest dose rate, radium release, and external hazard index were obtained for Mud Sample C whose radium equivalent was judged to be far below the critical safe limit for the drillers. The radium equivalent activity for the two field mud samples (C and D) were estimated to be 27.467 and 22.978 Bq kg⁻¹, respectively, which is the maximum activity obtained for the analyzed samples. The maximum radium equivalent activity for Mud Sample C was estimated as 27.48 Bq kg⁻¹ with a corresponding external hazard index of 0.7. Based on the analysis, there is a significant correlation between the concentration of heavy metals and the radionuclides found in the mud samples.

Methylmercury (MeHg⁺) is a neurotoxicant abundantly present in the environment. The long-term effects of MeHg⁺ have been investigated in rodents, yet data on the long-term or persisted toxicity of MeHg⁺ in invertebrates is scanty. Here, we examined the acute, intermediate, and chronic effects upon dietary administration of MeHg⁺ in nymphs of Nauphoeta cinerea. Besides, the potential reversibility of the toxic effects of MeHg⁺ after a detoxification period was evaluated. Nymphs were exposed to diets containing 0 (control), 2.5, 25, and 100 μg MeHg⁺/g of diet for 10, 30, and 90 days. Additional groups of nymphs were fed with the same dose of MeHg⁺ for 30 days and then were subjected to a detoxification period for 60 days. The nymphs exposed to 100 μg MeHg⁺/g succumbed to a high mortality rate, along with multiple biochemical (increase of reactive oxygen species production and glutathione S-transferase activity, as well as decrease in the acetylcholinesterase activity) and behavioral alterations. We observed delayed mortality rate and behavioral alterations in nymphs exposed to 100 μg MeHg⁺/g for 30 days and subsequently subjected to 60 days of detoxification. However, the biochemical alterations did not persist throughout the detoxification period. In conclusion, our results established the persistent toxic effect of MeHg⁺ even after a prolonged detoxification period and evidenced the use of N. cinerea as an alternative model to study the toxicity of MeHg⁺.

To understand the potential environmental influence of animal manure under freeze-thaw cycles, pig manure was used to conduct a simulation experiment to explore the effects of freeze-thaw cycles on heavy metal distribution and form transformation. Thirty cycles of freezing and thawing were performed alternately by freezing at − 18 ± 2 °C for 24 h and thawing at 20 ± 2 °C for 24 h. By a serial wet sieving procedure, manure samples were separated into different sizes of 1000, 250, 75, 38, and < 38 μm. Solid samples were collected from the dry matter at each stage of sieve; then the washing waters were collected as liquid samples accordingly. The concentrations of heavy metals in solid/liquid samples and their five forms were analyzed. It showed that the concentrations of heavy metals in the solid and liquid samples gradually increased because of organic matter degradation during freezing and thawing cycles. The distribution of heavy metals on particles of different sizes was also affected by the degradation and breakup of pig manure; the metals showed a tendency to aggregate in small particles (< 38 μm). Among them, the percentage of Cu and Zn on < 38 μm particles increased by 162.3% and 554.1%, respectively. After several freeze-thaw cycles, the concentrations of EXCH-X (metals of exchangeable form) increased significantly, those of CARB-X (carbonate-bound form) and Fe/Mn-X (Fe/Mn oxide-bound form) decreased accordingly. These form transformations may be largely influenced by the enhancement of dissolved organic matter (DOM) and the reduction of pH value. Therefore, frequent freeze-thaw cycles may promote the mobility and bioavailability of heavy metals in pig manure. The results are significant for understanding the pollution risk of pig manure in the freeze-thaw regions.

Statistics from the Intergovernmental Panel on Climate Change (IPCC) reveals that energy consumption remains the main root cause of anthropogenic greenhouse pollutant emissions because of economic expansion. Thus, the need to explore the determinants of environmental degradation in South Africa is pertinent for policymakers and stakeholders. The current study is conducted in a multivariate framework using an augmented carbon income function. The present study explores the theme under review with the inclusion of total natural resource rent as an additional variable to circumvent for omitted variable bias. To this end, annual time series data from 1970 to 2017 is employed for econometrics analysis. The study set off with investigation of stationarity properties with conventional unit root test in conjunction with Zivot-Andrews unit root test that accounts for single structural break. The Pesaran’s bounds testing techniques traces long-run equilibrium relationship between energy (coal) consumption, pollutant emission, total natural resources rent, and economic expansion over the sampled period. Empirical test from the modified Wald test detect and validate feedback causality between energy (coal) consumption and economic expansion. This is instructive to energy stakeholders and policymakers that energy is key determinant of economic growth. Furthermore, total natural resources rent shows significant contribution to pollutant emissions in South Africa. Based on the empirical results, policy direction such as adoption of new technologies and cleaner energy sources were suggested rather than fossil fuel driven economy in South Africa.

Counterpart cooperation is a major innovative measure in China’s strategy for revitalizing north-eastern China. While promoting economic progress, regional counterpart cooperation should also focus on low-carbon economy and sustainable development. Under the background of China’s proposed innovative cooperation strategy, using a multi-regional input-output (MRIO) model and structural decomposition analysis (SDA), this study takes Jilin province and its counterpart Zhejiang province as an example and decomposes the change in carbon emission intensity (CEI), which is a widely used indicator to measure regional carbon emission performance. The decomposition spans the years 2007 to 2012, at the level of two provinces and departments. By comparing the factors that drive and inhibit CEI in the two provinces, it was found that the production technology effect in Jilin province primarily drove the growth in CEI, while in Zhejiang province, the opposite occurred. Second, the structural effects of agriculture and heavy industry in Jilin province accounted for the largest proportion of this change, and the pulling effect on the increase in CEI in Jilin was significantly higher than that in Zhejiang province. Third, the scale effect of agricultural demand in Zhejiang province was much higher than that in Jilin province, and the same trend was observed for the scale effect of heavy industrial exports.

The short-term effects of ivermectin (IVMT) on the oxidative stress and biochemical parameters of Clarias gariepinus juvenile was assessed under semi-static conditions at concentrations of 9 to 25 μg L⁻¹ for up to 4 days. Juveniles were highly sensitive to ivermectin, with an LC₅₀ of 15 μg L⁻¹.The antioxidant enzyme profile assessed included glutathione reductase (GR), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). General stress biomarkers such as serum glucose, protein, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were also determined at 24-h, 48-h, 72-h, and 96-h exposure durations. Lipid peroxidation showed significant (p < 0.05) decreases in higher concentrations (21 μg L⁻¹and 25 μg L⁻¹) and durations of exposure (72 h and 96 h). Significant concentration-dependent increases (p < 0.05) were recorded in the liver function enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) when compared to the control. GPx decreased significantly (p < 0.05) in higher concentrations (21 μg L⁻¹and 25 μg L⁻¹) and durations of exposure (48–96 h). Protein showed significant concentration-dependent decreases, while glucose recorded a mixed trend. The changes in the hepatic antioxidant enzyme activities and serum metabolites were indicative of oxidative stress induced by IVMT. This showed that IVMT is toxic to fish and should be used with utmost caution.

Glyphosate is the active component of several commercial formulations as in Roundup®. The present study was investigated the toxic effects of pure glyphosate or Roundup® on the liver and small intestine of chick embryos. On day 6, a total of 180 fertile eggs injected with deionized water (control group), 10 mg pure glyphosate, or 10 mg of the active ingredient glyphosate in Roundup®/kg egg mass. The results showed an increase in relative weights of the liver in embryos that treated with Roundup®. Furthermore, oxidative stress was observed in the embryos treated with glyphosate or Roundup®, increased total superoxide dismutase, and content of malondialdehyde in the liver and intestine; moreover, decrease of glutathione peroxidase in the liver with increased in the intestine compared with the control. Besides, glutamic-pyruvic transaminase was increased in Roundup® group compared with other groups. Moreover, histopathological alterations in the liver and intestine tissues were observed in treated groups. Suppression of hepatic CYP1A2, CYP1A4, CYP1B1, and MDR1 mRNA expression after exposed to Roundup®. Furthermore, inhibition of CYP1A4 in the duodenum, CYP1A4, and MRP2 in the jejunum in embryos exposed to glyphosate or Roundup®. In addition, glyphosate treatment caused an increase of CYP3A5, CYP1C1, and IFNY mRNA expression in the jejunum and CYP1A2 expression in the ileum, while IFN-Y gene increase in embryos treated with Roundup®. In conclusion, in ovo exposure to glyphosate caused histopathological alterations and induced oxidative stress in the liver and small intestines. Moreover, the expression of cytochrome P450, MDR1, and MRP2 transporters was also modulated in the liver and small intestines for chick embryos.

The quality of soils polluted by trace elements around the facilities with the Cu and Zn smelting activities and the post-flotation tailings pond from copper industry were assessed. The level of the contamination of soils was determined on the basis of the contamination factor and the geoaccumulation index. The geoaccumulation index allows to distinguish more degrees of soil contamination and simplifies the assessment of the useable value of soil. The degrees of soil contamination and the pollution load index were shown. It has been shown that the pollution indices are a useful tool in describing the soil quality and planning corrective actions in the areas contaminated as a result of industrial activity. Histograms of pollution indices were used in order to detect the distribution of trace elements in soils. The content of metals in biomass was assessed using bioaccumulation indices. Triticum L. and Brassica napus L. show low bioaccumulation of studied metals in cereal plants. The correlations were used in order to detect the relationship among trace elements in soil as well as the relationship of metal (soil)-metal (plant) and metal bioaccumulation (plant)-metal (soil). The highest values of indices were recorded for the Oława smelter, presumably due to the long operation period before technological changes limiting the emission of pollutants were introduced. This research area was classified as very highly contaminated with all trace elements. Soils around other facilities are at least moderately contaminated.