Short-term effects of diesel fuel on rhizosphere microbial community structure of native plants in Yangtze estuarine wetland

Purpose

In this work, short-term effects of diesel fuel on Huangpu?CYangtze estuarine wetland soil microbial community structure were studied under simulated conditions through phospholipid fatty acids (PLFAs) analysis. Four native plant species, bulrush (Scirpus tripueter), galingale (Cyperus rotundus), wildrice (Zizania latifolia), and reed (Phragmites australis) were tested in the experiments.

Method

In the pot experiment, 20?g rhizosphere soils were mixed with 20?g diesel-blended soils. The concentration of total petroleum hydrocarbon was 16,000?mg/kg. All pots were incubated for 14?days in dark at 28°C and watered with 12?mL sterile distilled water to keep a liquid level. Microbial activity of the samples was assessed by hydrolysis of fluorescein diacetate. Measurements of soil PLFAs and analysis on gas chromatography were performed.

Results

The microbial activity in the samples of reed was highest after the exposure. In all samples, the common PLFA was straight-chain saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA). After the exposure the relative abundance of MUFA and polyunsaturated fatty acid decreased by 20%, and the relative abundance of straight-chain SFA increased by 20%. The results of diversity and PCA indicated that the effect of diesel pollutant on the microbial community was far stronger than the root effect and the reed roots enhanced the tolerance of soil microorganisms to diesel significantly.

Conclusions

All results showed that the soil microbial community structure differed significantly with the exposure to diesel. In reed rhizosphere, the soil microorganisms exhibited a strong resistance to diesel fuel. It confirmed that the root of reed improved the biodegradation ability of soil microorganisms for diesel pollutants and they could be reasonably matched to cure and restore the ecological environment of oil-contaminated wetlands.     

Levels of organochlorine pesticides in Amazon turtle (Podocnemis unifilis) in the Xingu River,Brazil

Abstract

Due to the toxicity and high environmental persistence of organochlorine pesticides in aquatic organisms, turtles have been studied as environment biomonitors. These animals are important sources of protein for the riverside and indigenous peoples of the Brazilian amazon. In the present study, organochlorine pesticide contamination was investigated in Podocnemis unifilis. Liver, muscle and fatty tissue samples were removed from 50 specimens collected from five sampling points located in the Xingu River basin. Fourteen organochlorine pesticides were analysed via gas chromatography with an electron capture detector (CG-ECD). Eight organochlorine pesticides were detected with average concentrations of ∑DDT, ∑Endossulfan and ∑HCH which were 26.17?±?26.35, 14.38?±?23.77 and 1.39?±?8.46?ng g^?1 in moisture content, respectively. DDT compounds were the most predominant, with a greater concentration of pp′-DDT in the liver and pp′-DDD in the muscle. Significant differences were noted between the types of tissues studied, and the concentration of OCPs varied between sampling sites.     

Enhancement of nutritional value of fried fish using an artificial intelligence approach

Frying affects the nutritional quality of fish detrimentally. In this study, using Catla catla and mustard oil, experiments were carried out in varying temperatures (140–240 °C), times (5–20 min), and oil amounts (25–100 ml/kg of fish) which established drastic reduction of 44.97% and 99.40% for polyunsaturated fatty acid (PUFA)/saturated fatty acids (SFA) and index of atherogenicity (IA) profile, respectively. Artificial neural network (ANN) was implemented successfully to provide an association between the independent inputs with dependent outputs (values of R² were 0.99 and 0.98; RMSE were 0.038 and 0.046; and performance were 0.038 and 0.067 for PUFA/SFA and IA, respectively) by exhaustive search of various algorithms and activation functions available in literature. ANN model–based meta-heuristic, stochastic optimization formalisms, genetic algorithm (GA) and particle swarm optimization (PSO), were applied to optimize the combination of cooking parameters for improving the nutritional quality of food which improved the nutritional value by maximizing the PUFA/SFA profile up to 63.05% and minimizing the IA profile to 99.64%. Multi-objective genetic algorithm (MOGA) was also employed to tune the inputs by maintaining a balance between the contrasting outputs and enhance the overall food value simultaneously with multi-objective (beneficial for health, economic, and environment-friendly) proposal. MOGA was able to improve the PUFA/SFA profile up to 44.76% and reduce the IA profile to 92.94% concurrently with the reduction of wastage of culinary media and energy consumption, following the optimized cooking condition (118.92 °C, 6.06 min, 40 ml oil/kg of fish).

     

Plot-scale spatiotemporal variations of CO2 concentration and flux across water–air interfaces at aquaculture shrimp ponds in a subtropical estuary

Human activities have increased anthropogenic CO₂ emissions, which are believed to play important roles in global warming. The spatiotemporal variations of CO₂ concentration and flux at fine spatial scales in aquaculture ponds remain unclear, particularly in China, the country with the largest aquaculture. In this study, the plot-scale spatiotemporal variations of water CO₂ concentration and flux, both within and among ponds, were researched in shrimp ponds in Shanyutan Wetland, Min River Estuary, Southeast China. The average water CO₂ concentration and flux across the water–air interface in the shrimp ponds over the shrimp farming period varied from 22.79?±?0.54 to 186.66?±?8.71 μmol L^?1 and from ??0.50?±?0.04 to 2.87?±?0.78 mol m^?2 day^?1, respectively. There was no remarkable difference in CO₂ concentration and flux within the ponds, but significantly spatiotemporal differences in CO₂ flux were observed between shrimp ponds. Chlorophyll a, pH, salinity, air temperature, and morphometry were the important factors driving the spatiotemporal patterns of CO₂ flux in the shrimp ponds. Our findings highlighted the importance and spatiotemporal variations of CO₂ flux in the important coastal ecosystems.

     

The residual levels and health risks of hexachlorocyclohexanes (HCHs) and dichloro-diphenyl-trichloroethanes (DDTs) in the fish from Lake Baiyangdian, North China

The tissue and organs (muscle, brain, liver, and gill) of four species of freshwater fish from Lake Baiyangdian were analyzed for hexachlorocyclohexanes (HCHs) and dichloro-diphenyl-trichloroethanes (DDTs). The distribution characteristics were analyzed for HCHs and DDTs in various tissue and organs, which determined the health risks for humans. The research results showed that the wet weight content of all HCHs (∑HCHs) ranged from 0.05?～?14.53 ng?g^?1, with a mean of 3.47 ng?g^?1. The wet weight content of all DDTs (∑DDTs) ranged from ND to 8.51 ng?g^?1, with a mean of 2.41 ng?g^?1. For the various species of fish, the residual level of ∑HCHs was relatively higher in chub and grass carp and lowest in snakehead. The residual level of ∑DDTs was the highest in snakehead and did not exhibit a significant variance in the other three species. For the various tissues and organs, the contents of HCHs and DDTs were both highest in the fish liver, second highest in the fish gill, and lowest in the fish brain and muscle. Among the four types of isomers, the residual level of γ-HCH was relatively higher, while the residual level of α-HCH was the lowest. The content of p,p′-DDE was significantly greater to other forms of DDT and its isomer. The residual levels of HCHs and DDTs in fish were both below the national standard. However, the carcinogenic risk from the HCHs in parts of the tissue and organs of four fish species in Lake Baiyangdian exceeded the screen value threshold set by USEPA.     

Effects of sodium arsenate exposure on liver fatty acid profiles and oxidative stress in rats

The present study aimed to evaluate the effect of arsenic on liver fatty acids (FA) composition, hepatotoxicity and oxidative status markers in rats. Male rats were randomly devised to six groups (n?=?10 per group) and exposed to sodium arsenate at a dose of 1 and 10 mg/l for 45 and 90 days. Arsenate exposure is associated with significant changes in the FA composition in liver. A significant increase of saturated fatty acids (SFA) in all treated groups (p?<?0.01) and trans unsaturated fatty acids (trans UFA) in rats exposed both for short term for 10 mg/l (p?<?0.05) and long term for 1 and 10 mg/l (p?<?0.001) was observed. However, the cis UFA were significantly decreased in these groups (p?<?0.05). A markedly increase of indicator in cell membrane viscosity expressed as SFA/UFA was reported in the treated groups (p?<?0.001). A significant increase in the level of malondialdehyde by 38.3 % after 90 days of exposure at 10 mg/l was observed. Compared to control rats, significant liver damage was observed at 10 mg/l of arsenate by increasing plasma marker enzymes after 90 days. It is through the histological investigations in hepatic tissues of exposed rats that these damage effects of arsenate were confirmed. The antioxidant perturbations were observed to be more important at groups treated by the high dose (p?<?0.05). An increase in the level of protein carbonyls was observed in all treated groups (p?<?0.05). The present study provides evidence for a direct effect of arsenite on FA composition disturbance causing an increase of SFA and TFAs isomers, liver dysfunction and oxidative stress. Therefore, arsenate can lead to hepatic damage and propensity towards liver cancer.     

Abundance and removal of antibiotic resistance genes (ARGs) in the rearing environments of intensive shrimp aquaculture in South China

Although research regarding antibiotic resistance genes (ARGs) in aquaculture environments has gained increasing scientific interest, further studies are required to understand the abundances and removal mechanisms of ARGs during the entire rearing period of shrimp aquaculture. Thus, in this study, abundances, distributions and removal rates of ARGs in different environmental compartments of intensive shrimp farms in South China were investigated during the entire rearing period. The results indicated that sul1 and cmlA were the predominant ARGs in the water and sediment samples. Additionally, the total abundance of ARGs was higher in shrimp pond water than in the source water and farm effluent. Moreover, sediment samples indicated significantly higher ARG abundances than water samples from the shrimp ponds (P?<?0.05). Environmental factors were found to significantly affect the distribution of ARGs in shrimp rearing environments. Furthermore, stable ponds aided the removal of ARGs from shrimp pond water. This study accounted for temporal variations in ARG abundances as well as removal of ARGs in different environmental compartments during the entire shrimp rearing period. However, additional research is required to optimize the water treatment process for removal of ARGs from the aquaculture.     

Organochlorine pesticides and polychlorinated biphenyls in soils surrounding the Tanggu Chemical Industrial District of Tianjin, China

The spatial distribution of persistent organic pollutants (POPs) was examined in soils surrounding the Tanggu Chemical Industrial District in Tianjin, China. The concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzenes (HCBs), and polychlorinated biphenyls (PCBs) were determined in 70 surface soils using accelerated solvent extraction and gas chromatography with electron capture detection. The results showed that the ranges of ∑HCH, ∑DDT, ΣHCB, and ∑PCB concentrations in soils were 2.1–12,549 μg?kg^?1 (average, 965 μg?kg^?1), n.d.–2,033 μg?kg^?1 (average, 88.4 μg?kg^?1), n.d.–1,924 μg?kg^?1 (average, 349 μg?kg^?1), and n.d.–373 μg?kg^?1 (average, 46.2 μg?kg^?1), respectively. Of these, HCHs were the dominant POPs, accounting for 75 % of the total organochlorine pesticide (OCP) residues. Overall, the spatial distribution of OCP concentrations showed a decreasing trend from the center of the Tanggu District to the surrounding areas. Two major pollution sources were Tianjin Dagu Chemical Co., Ltd. in the district center and the Tianjin Chemical Plant in Hangu District. In contrast, PCB concentrations were relatively high in the Haihe estuary to the east and low to the west of the study area. Component analysis of OCPs in these soils showed that they mainly came from industrial point sources. Compared with soils in other regions, soil DDT pollution was at a medium level in the Tanggu Chemical Industrial District, but associated HCH, HCB, and PCB pollution was relatively heavy. By multivariate statistical analyses, Tianjin Dagu Chemical Co., Ltd. was recognized as the main source of POPs, and soil properties were clarified to play an important role on the distribution and composition of POPs, especially the organic carbon content.     

Occurrence and distribution of heavy metals and tetracyclines in agricultural soils after typical land use change in east China

Land use in east China tends to change from paddy rice to vegetables or other high-value cash crops, resulting in high input rates of organic manures and increased risk of contamination with both heavy metals (HMs) and antibiotics. This investigation was conducted to determine the accumulation, distribution and risks of HMs and tetracyclines (TCs) in surface soils and profiles receiving different amounts of farmyard manure. Soil samples collected from suburbs of Hangzhou city, Zhejiang province were introduced to represent three types of land use change from paddy rice to asparagus production, vineyards and field mustard cultivation, and divided into two portions, one of which was air-dried and sieved through 2-, 0.3- and 0.149-mm nylon mesh for determination of pH and heavy metals. The other portion was frozen at ?20 °C, freeze-dried and sieved through a 0.3-mm nylon mesh for tetracyline determination. HM and TC concentrations in surface soils of 14-year-old mustard fields were the highest with total Cu, Zn, Cd and ∑TCs of 50.5, 196, 1.03 mg?kg^?1 and 22.9 μg?kg^?1, respectively, on average. The total Cu sequence was field mustard?>?vineyards?>?asparagus when duration of land use change was considered; oxytetracycline (OTC) and doxycycline were dominant in soils used for asparagus production; OTC was dominant in vineyards and chlortetracycline (CTC) was dominant in mustard soils. There were positive pollution relationships among Cu, Zn and ∑TCs, especially between Cu and Zn or Cu and ∑TCs. Repeated and excessive application of manures from intensive farming systems may produce combined contamination with HMs and TCs which were found in the top 20 cm of the arable soil profiles and also extended to 20–40 cm depth. Increasing manure application rate and cultivation time led to continuing increases in residue concentrations and movement down the soil profile.     

Distribution,possible sources,and health risk assessment of SVOC pollution in small streams in Pearl River Delta,China

The pollution levels of typical semivolatile organic compounds (SVOCs) consisting of 15 polycyclic aromatic hydrocarbons (PAHs), 20 organic chlorinated pesticides (OCPs), and 15 phthalate esters (PAEs) were investigated in small rivers running through the flourishing cities in Pearl River Delta region, China. The concentrations of ∑15PAHs were 2.0–48 ng/L and 29–1.2?×?10³ ng/g in the water and sediment samples, respectively. The ∑20OCPs were 6.6–57 ng/L and 9.3–6.0?×?10² ng/g in the water and sediment samples, respectively. The concentrations of ∑15PAEs were much higher both in the water and sediments. The partition process of the detected SVOCs between the water and sediment did not reach the equilibrium state at most of the sites when sampling. The combustion of petroleum products and coal was the major source of the detected PAHs. The OCPs were mainly historical residue, whereas the new inputs of dichlorodiphenyltrichloroethane (DDT), chlordane, and endosulfan were possible at several sites. The industrial and domestic sewage were the major source for the PAEs; storm water runoff accelerated the input of PAEs. No chronic risk of the SVOCs was identified by a health risk assessment through daily water consumption, except for the ∑20OCPs that might cause cancer at several sites. Nevertheless, the integrated health risk of the SVOCs should not be neglected and need intensive investigations.     

Accumulation pattern and distribution of polycyclic aromatic hydrocarbons (PAHs) in liver tissues of seven species of birds from Ahmedabad, India, during 2005–2007

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured in liver tissues of seven species of birds collected from Ahmedabad, India during 2005–2007. All the samples collected were dead as victims of kite flying. Concentrations of ∑PAHs in livers of birds were ranged from 110?±?32.6 ng/g wet wt (1,078?±?320 lipid wt) in common myna Acridotheres tristis to 382?±?90.1 ng/g (2,388?±?563 lipid wt) in white-backed vulture. Statistically significant (p?<?0.05) differences in ∑PAHs were observed among species. However, year of collection and sex of birds did not show significant differences in concentrations of PAHs. The levels of ∑PAHs measured in the present study species were higher than the levels documented for a number of avian species and were lower than those reported to have deleterious effects on survival or reproduction of birds. Presence of PAH residues in birds of Ahmedabad city show the continuous input of PAHs through environmental exposure. Although no threat is posed by any of the hydrocarbons detected, continuous monitoring of breeding colonies of birds is recommended in unpolluted reference sites as well as polluted sites. It is also the first account of a comprehensive analysis of PAHs in various species of birds in India. Therefore, the values reported in this study can serve as baseline values for future research.     

Chronic copper exposure and fatty acid composition of the amphipod Dikerogammarus villosus: results from a field study

Field study allows assessment of long-term effects on fatty acid (FA) composition of organisms under chronic exposure to metals. One expected effect of copper is peroxidation of lipids and essentially polyunsaturated fatty acids (PUFA). FA analysis was established for the amphipod Dikerogammarus villosus subjected to different degrees of copper exposure (4–40 μg Cu L⁻¹). A previous study in our team showed that this species regulates its body Cu concentration (106–135 mg Cu kg⁻¹ dry weight). Despite the high capacity of bioaccumulation, the absence of a correlation between copper concentration in D. villosus and water prevents its use as bioindicator of copper pollution. Both sexes from the most polluted site showed the lowest total FA content, but the highest PUFA percent, mainly of the long-chained variety (C20–C22). Mechanisms leading to the prevention of lipid peroxidation in this species were discussed (metallothioneins and intracellular granules) and proposed with support from literature data.     

Screening of human health risk to infants associated with the polychlorinated biphenyl (PCB) levels in human milk from Punjab Province,Pakistan

This study assessed the polychlorinated biphenyl (PCB) levels in human milk and its associated health risk to infants from rural and urban settings of five districts of Punjab Province, Pakistan. The ∑₃₄PCB concentrations ranged from 30.9 to 68.3 ng g^?1 on lipid weight (l.w.) basis. The ∑₈DL-PCB concentrations were ranged from 0.29 to 1.35 ng g^?1 l.w., (mean 6.2 ± 8.7 ng g^?1 l.w.), with toxicity equivalent to polychlorinated dibenzodioxins (PCDDs) ranging from 8.58 × 10^?6 to 0.05 ng TEQ g^?1 l.w. The spatial trend of PCB levels in human milk revealed higher bioaccumulative levels for urban mothers as compared with rural counterparts. The estimated daily intake (EDI) values of DL-PCBs to infants through trans-mammary transfer were considerably higher than tolerable daily intake limits established by WHO (i.e., 1–4 pg TEQ kg^?1 bw) and other globally recognized organizations. Similarly, the hazard quotient values for TEQ ∑₈DL-PCBs (range 1.21 to 79.87) were far above the benchmark value of 1 at all the sampling sites, indicating the high levels of adverse health risks to infants in the region through breast milk consumption. The ∑₃₄PCB levels were found to be negatively correlated with mother’ age (r = ?0.31; p = 0.02), parity (r = ? 0.85; p = 0.001), and infant’ birth weight (r = ? 0.73; p = 0.01). The present study suggests undertaking comprehensive public health risk assessment studies and firm regulatory measures to safeguard human health risks.

     

Concentrations of organochlorine pesticides and polychlorinated biphenyls in human serum and their relation with age,gender, and BMI for the general population of Bizerte,Tunisia

Human serum samples (n?=?113) from Bizerte, northern Tunisia, collected between 2011 and 2012 were analyzed for 8 organochlorine pesticides (OCPs) including p,p′-dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), hexachlorocyclohexane isomers, dieldrin, and heptachlor and 12 polychlorinated biphenyls (PCBs) congeners. Concentrations of these residues in serum were determined by gas chromatography with electron capture detector and total cholesterol (CHOL) and triglycerides (TG) levels were evaluated by enzymatic colorimetric method. HCB, p,p′-DDE, PCB-138, PCB-153, and PCB-180, were the most abundant organochlorine compounds (OCs) detected in >95 % of the study subjects. The mean levels of p,p′-DDE and HCB in serum were 168.8 and 49.1 ng?g^?1 lipid, respectively. The sum PCBs concentrations ranged from 37.5 to 284.6 ng?g^?1 lipid in the samples, with mean and median value of 136.1 and 123.2 ng?g^?1 lipid, respectively. The PCB profile consisted of persistent congeners, such as PCB-138, PCB-153, and PCB-180 which contributed for approximately 82.7 % to the ∑PCBs. Statistical analysis showed that most OCs correlated significantly with age, considering all samples together or with gender differentiation. The present study shows that the levels of p,p′-DDE and ∑DDTs were significantly higher in females than in males (p?<?0.05), while PCBs levels were significantly higher in male (p?<?0.05) than in females. No statistically significant association was found between body mass index and concentration of any organochlorine pesticide or PCB congeners 153, 138, 180, or ∑PCBs.     

Temporal variation and spatial distribution of PAH in water of Three Gorges Reservoir during the complete impoundment period

Bioavailable concentrations of polycyclic aromatic hydrocarbons (PAHs) were investigated in water of Three Gorges Reservoir (TGR) using semipermeable membrane devices during the period of completely impounding water. ∑PAH concentrations in water of TGR in the period of completely impounding water were 15–381 ng?L^?1. ∑PAH concentrations increased from town or counties to big industrialized cities in TGR, indicating urbanization effects on PAH pollution in the water. Tributaries in TGR have a certain contribution of PAH pollution to the mainstream of Yangtze River and their pollution could not be neglected. An obvious decrease of PAH concentration was observed after 175-m water impounding in 2011 in TGR. Several factors may account for this decrease, including execution of comprehensive treatment and management measures in TGR, less rainfall in 2011, and sedimentation effect caused by the dam. Passive sampling method has been successfully applied in the investigation of trace PAH in water of TGR and proved to be a useful and efficient tool for the management and sustainable development of the big reservoir. The results of the study provide valuable information about PAH pollution in the whole reservoir including some tributaries, and the pollution status is dynamically related with human activities. Therefore, PAH could be used as a marker compound or indicator in the network monitoring system to surveil and trace the pollution status in TGR.     

Contamination of organochlorine pesticides in water and sediments from a waterbird-inhabited lake,East Central China

Seventeen organochlorine pesticides (OCPs) were investigated in the water and sediments from a waterbird-inhabited lake (Yangchaihu Lake) to evaluate their current pollution levels and potential risks. The concentrations of total OCPs in water and sediments were 10.12–59.75 ng/l and 4.25–27.35 ng/g dry weight, respectively. Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the most abundant OCPs, while HCB and cyclodiene pesticides were detected with low levels. Levels of ∑OCPs (sum of 17 OCPs) at sites highly influenced by waterbirds were significantly higher than the sites with no significant waterbird populations (one-way ANOVA, P?相似文献   

Origin and vertical variation of the bound fatty acids in core sediments of Lake Dianchi in Southwest China

Based on the molecular distribution of bound fatty acid (BFA) compound classes in core sediments of Lake Dianchi combined with the compound-specific δ¹³C values of the straight-chain BFAs, origin and vertical changes of organic matters in the sediments were investigated. The results indicated a significant change of BFA sources over the past 700 years. Contrast to the low concentrations of the terrestrial BFAs, the abundance of BFAs derived from the plankton/bacteria in the top sections (1944–recent) was more than 80 %. The increasing proportions of the branched and unsaturated BFAs in total fatty acids were closely correlated with the heavy eutrophication and the frequent algal blooms in the decades. Furthermore, the positive shift of δ ¹³C of C16 and C18 (~2?‰) in the upper section might be an indicator of the excess phytoplankton productivity. However, it was found that the plankton/bacteria-derived BFAs were more easily degraded during the early diagenetic process. The special compound carbon isotopic compositions of the long straight-chain BFAs (C24 and C26) in the sediments showed a depletion of heavier δ ¹³C values (ca. ?30?‰) in the midsections (1559–1787), reflecting a relatively growing contribution of C3 plants to C4 plants or that C4 plant growth was inhibited in cold and arid climates during the period.     

Adaptive alterations in the fatty acids composition under induced oxidative stress in heavy metal-tolerant filamentous fungus Paecilomyces marquandii cultured in ascorbic acid presence

The ability of the heavy metal-tolerant fungus Paecilomyces marquandii to modulate whole cells fatty acid composition and saturation in response to IC₅₀ of Cd, Pb, Zn, Ni, and Cu was studied. Cadmium and nickel caused the most significant growth reduction. In the mycelia cultured with all tested metals, with the exception of nickel, a rise in the fatty acid unsaturation was noted. The fungus exposure to Pb, Cu, and Ni led to significantly higher lipid peroxidation. P. marquandii incubated in the presence of the tested metals responded with an increase in the level of linoleic acid and escalation of electrolyte leakage. The highest efflux of electrolytes was caused by lead. In these conditions, the fungus was able to bind up to 100 mg?g^?1 of lead, whereas the content of the other metals in the mycelium was significantly lower and reached from 3.18 mg?g^?1 (Cu) to 15.21 mg?g^?1 (Zn). Additionally, it was shown that ascorbic acid at the concentration of 1 mM protected fungal growth and prevented the changes in the fatty acid composition and saturation but did not alleviate lipid peroxidation or affect the increased permeability of membranes after lead exposure. Pro-oxidant properties of ascorbic acid in the copper-stressed cells manifested strong growth inhibition and enhanced metal accumulation as a result of membrane damage. Toxic metals action caused cellular modulations, which might contributed to P. marquandii tolerance to the studied metals. Moreover, these changes can enhance metal removal from contaminated environment.     

Health risk assessment for consumption of fish originating from ponds near Dabaoshan mine, South China

Mining effluents are a potential source of toxic metals in the surrounding aquatic ecosystem and pose a potential health risk to humans from fish consumption. The objective of this paper is to assess the impact of the long-term Dabaoshan mining operation on heavy metal accumulation in different fish species. Heavy metal accumulation (lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu)) in four tissues (liver, muscle, intestine, and gills) of five carp species (Hypophthalmichthys molitrix, Ctenopharyngodon idellus, Megalobrama amblycephala, Aristichthys nobilis, and Carassius auratus auratus) from two fishponds exposed to effluent waters from Dabaoshan mine, South China. The bioaccumulation factor (BAF) and target hazard quotients were calculated to assess potential health risks to local residents through fish consumption. Levels of heavy metals varied depending on the analyzed tissues. C. auratus auratus accumulated the higher Pb, Cd, Zn, and Cu in the intestine compared with other fish species. Liver of all five species contained high concentrations of Pb, Cd, Zn, and Cu. The BAF for the studied metals showed a descending order of Cd?>?Zn?>?Cu?>?Pb for fishpond 1 and Zn?>?Cd?>?Cu?>?Pb for fishpond 2. Risk assessments suggested that potential human health risk may be present due to high Pb and Cd concentration in the muscle of some fish species exceeding the national and international limits, although the target hazard quotients were less than one.     

Levels, compositions, and inventory of polybrominated diphenyl ethers in sewage sludge of Guangdong Province, South China

Polybrominated diphenyl ethers (PBDEs) were measured in sewage sludge samples collected from major wastewater treatment plants in Guangdong Province, South China. Concentrations of ∑₃₉PBDE (all 39 compounds including tri- to hepta- PBDE congeners except for BDE-209) ranged from 3.6 to 428 ng/g dw with a mean value of 67.4 ng/g dw and a median value of 25.9 ng/g dw, and those of BDE-209 ranged from 9.9 to 5,010 ng/g dw (mean 1,024 ng/g dw and median 824 ng/g dw). The PBDE mixtures detected were mainly comprised of penta-, octa-, and deca-BDEs, with deca-BDE as the dominant constituent. The most abundant congeners, excluding BDE-209, were BDE-47, BDE-99, and BDE-183. Good correlations were found among the concentrations of BDE-47, BDE-99, BDE-100, BDE-138, and BDE-154 (r?>?0.8). However, poor correlations were found between the concentrations of BDE-209 and all other congeners (r?<?0.3). This fact suggests that most tri- to hepta-BDEs detected did not originate from decomposition of deca-BDE. The estimated annual emission of ∑_allPBDEs, ∑₃₉PBDEs, penta-BDE, octa-BDE, and deca-BDE to the Pearl River Delta environment (PRD), based on the sludge samples analyzed, amounts to 232, 20.2, 5.5, 1.7, and 212 kg per year, implicating sewage sludge as a significant source of PBDEs to the PRD environment.