Polycyclic aromatic hydrocarbons in surface sediment of typical estuaries and the spatial distribution in Haihe river basin

Polycyclic aromatic hydrocarbons (PAHs) with carcinogenic and mutagenic characteristics have been detected in many estuaries and bays around the world. To detect the contaminated level in typical estuaries in Haihe river basin, China, a comprehensive survey of 16 PAHs in surface sediment has been conducted and an ecological risk assessment has been taken. It showed that Haihe river estuary had the highest concentration, ranging from 92.91 to 15886.00 ng g^?1. And Luan river estuary has the lowest polluted level, ranging from 39.55 to 328.10 ng g^?1. PAHs in sediment were dominated by low and mid molecular weight PAHs in all the sampling sites. Most of the sampling sites in all sampling seasons indicated a rarely happened ecological risk of ΣPAHs, while the S6 in Haihe river estuary was in an occasionally anticipated risk. To illustrate the spatial distribution pattern of PAHs in surface sediment in Haihe river basin, the results were compared with previous research of the research team. Based on data of the comparison, it had been revealed that Haihe river had the most serious PAHs pollution, with an average concentration of 5884.86 ng g^?1, and showed the highest contamination level in all four ecological units. The ΣPAHs concentration showed in a rank of reservoir > estuary > rural area > city.     

Distribution,potential source and ecotoxicological risk of polychlorinated biphenyls and polybrominated diphenyl ethers in the surface water of the Three Gorges Dam region of the Yangtze River,China

Distributions, potential sources and ecotoxicological risks of PCBs and PBDEs in surface water of the Three Gorges Dam (TGD) region (Yangtze River, China) were investigated. Samples were collected from 18 sites from upstream (UTGD) and downstream (DTGD) of the TGD. Thirty-two PCBs and ten PBDEs were analyzed. ΣPCBs from the UTGD and DTGD ranged from 10.6 to 26.1 and 1.7 to 29.8 ng L^?1, respectively. ΣPBDEs from the UTGD and DTGD ranged from 2.0 to 17.6 and 0.8 to 11.1 ng L^?1, respectively. The total concentrations of PCBs and PBDEs showed a declining trend from the UTGD to DTGD. Independent-samples t test analysis showed no statistical significance of ΣPCBs and ΣPBDEs between the UTGD and DTGD samples. Principal component analysis indicated the difference of potential sources and levels of PCBs and PBDEs in the study area. The potential eco-toxicological risk of PCBs in surface water of the TGD region is very low, whereas special attention needs to be paid to PBDEs in the study area.     

Contamination of aquatic system by chlorinated pesticides and their spatial distribution over North-East India

Organochlorine pesticides, the potential chemical pollutants, are extensively used for agriculture and vector control purposes due to their low cost and high effectiveness. DDT and HCH residues were examined in different surface and groundwater resources of district Dibrugarh and Nagaon of Assam state, Northeast India. The mean HCH concentrations in surface water samples were 4403 ng/L and 4911 ng/L, while 5168 ng/L and 5574 ng/L in groundwater samples from Dibrugarh and Nagaon districts respectively. Total DDT levels were 5402 ng/L and 6121 ng/L in surface water while 6549 ng/L and 6904 ng/L in groundwater from Dibrugarh and Nagaon respectively. DDT levels in groundwater were found to be highest among the levels reported so far. The dominant OCPs were found to be β-HCH among HCHs and p,p′-DDT among DDTs. The ratios of DDT/(DDE+DDD) and α-HCH/γ-HCH revealed that residue levels in water were originated from long past to recent mixed source of technical HCH and lindane for HCHs and mainly technical DDT for DDTs. About 93% samples for DDT and 90% samples for HCH exceeded the WHO recommended drinking water limits which is a matter of great concern and posing a serious threat to aquatic ecosystem and human health. Spatial distribution was also investigated to identify the areas with higher pesticide loadings in groundwater. Present data on contamination profile of OCPs in this survey can be used as reference levels for future POPs monitoring programme.     

Nondestructive indices of mercury exposure in three species of turtles occupying different trophic niches downstream from a former chloralkali facility

Turtles are useful for studying bioaccumulative pollutants such as mercury (Hg) because they have long life spans and feed at trophic levels that result in high exposure to anthropogenic chemicals. We compared total Hg concentrations in blood and toenails of three species of turtles (Chelydra serpentina, Sternotherus odoratus, and Graptemys geographica) with different feeding ecologies from locations up- and downstream of a superfund site in Virginia, USA. Mercury concentrations in turtle tissues were low at the reference site (average ± 1SE: blood = 48 ± 6 ng g^?1; nail = 2,464 ± 339 ng g^?1 FW) but rose near the contamination source to concentrations among the highest ever reported in turtles [up to 1,800 ng g^?1 (blood) and 42,250 ng g^?1 (nail) FW]. Tissue concentrations remained elevated ~130 km downstream from the source compared to reference concentrations. Tissue Hg concentrations were higher for C. serpentina and S. odoratus than G. geographica, consistent with the feeding ecology and our stable isotope (??¹³C and ??¹⁵N) analyses of these species. In addition, we suggest that toenails were a better indication of Hg exposure than blood, probably because this keratinized tissue represents integrated exposure over time. Our results demonstrate that downstream transport of Hg from point sources can persist over vast expanses of river thereby posing potential exposure risks to turtles, but relative exposure varies with trophic level. In addition, our study identifies turtle toenails as a simple, cost-efficient, and minimally invasive tissue for conservation-minded sampling of these long-lived vertebrates.     

Organochlorine pesticides and polychlorinated biphenyls in fin whales (Balaenoptera physalus) from the Gulf of California

The present study reports unique data on concentrations of several classes of organochlorine pesticides and polychlorinated biphenyls in blubber biopsies from healthy living fin whales (Balaenoptera physalus) from the Gulf of California, Mexico, one of the most isolated and unstudied population in the world. OC levels in this population were generally lower than levels reported in fin whales from other regions. The rank order of OCs were ∑DDTs (range from 300 to 2400 ng g^?1 lw) > ∑PCBs (range from 40 to 290 ng g^?1 lw) > ∑HCHs (range from ?1 lw) ≥ ∑CHLORs (from < LOQ to 100 ng g^?1 lw). The most abundant OC pesticide measured was the DDT metabolite, p,p′‐DDE. The PCBs 138, 153, and 180 were the most abundant PCBs congeners found in the fin whales samples. Males had significant higher concentrations of ∑OC, ∑DDTs and ∑PCBs than females (P < 0.05), although the p,p′‐DDE/∑DDTs ratios were similar between the sexes. Although the OC concentrations found in this population were generally below the levels that would be expected to cause deleterious health effects, the maximum values observed (2700 ng g^?1 lw) in some animals were higher than those associated with reproductive effects in whales. Given the small population size and highly isolated characteristics of Gulf of California fin whales, health effects in individuals could readily translate into population‐level effects. Future research on this topic will be necessary to better understand the role that these compounds may have on the health of this population. © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 381–390, 2010.     

Distribution and ecological risk assessment of organochlorine pesticides in sediments from four lakes of Heilongjiang Province,China

There is growing concern for the lake environment because polluted sediments may cause ecotoxicological effects. In the current study, persistent organochlorine compounds (OCPs), including hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and cyclodienes, were analyzed in core sediments taken from Huoshaohei Lake, Xihulu Lake, Wanghua Lake and Keqin Lake, Heilongjiang Province, China. The total OCPs concentrations ranged from 0.92 to 7.09, 0.15 to 9.95, 0.19 to 1.84 and 0.06 to 3.52 ng/g, respectively. The most dominant pollutants were the HCHs, high proportions of γ-HCH isomer indicating the recent input of lindane. The ratios of α-HCH/γ-HCH of four lakes are all lower than that in technical HCH mixtures indicating that there was input of lindane in the past several years, and the mean ratios of (DDE+DDD)/DDTs are all <0.5, suggesting recent release of DDT compounds. Compared with the corresponding ecological environmental quality guidelines from Ingersoll and base on the model of risk based corrective action environmental health risk assessment, the sediments from the four lakes poses a lower potential hazard to human health and the environment but still should be taken into account.     

Chemical fate and biological effects of several endocrine disrupters compounds in two echinoderm species

Two echinoderm species, the sea urchin Paracentrotus lividus and the feather star Antedon mediterranea, were exposed for 28 days to several EDCs: three putative androgenic compounds, triphenyltin (TPT), fenarimol (FEN), methyltestosterone (MET), and two putative antiandrogenic compounds, p,p′-DDE (DDE) and cyproterone acetate (CPA). The exposure nominal concentrations were from 10 to 3000 ng L^?1, depending on the compound. This paper is an attempt to join three different aspects coming from our ecotoxicological tests: (1) the chemical behaviour inside the experimental system; (2) the measured toxicological endpoints; (3) the biochemical responses, to which the measured endpoints may depend. The chemical fate of the different compounds was enquired by a modelling approach throughout the application of the ‘Aquarium model’. An estimation of the day-to-day concentration levels in water and biota were obtained together with the amount assumed each day by each animal (uptake in μg animal^?1 d^?1 or ng g-wet weight^?1 d^?1). The toxicological endpoints investigated deal with the reproductive potential (gonad maturation stage, gonad index and oocyte diameter) and with the regenerative potential (growth and histology). Almost all the compounds exerted some kind of effect at the tested concentrations, however TPT was the most effective in altering both reproductive and regenerative parameters (also at the concentration of few ng L^?1). The biochemical analyses of testosterone (T) and 17β-estradiol (E₂) also showed the ability of the selected compounds to significantly alter endogenous steroid concentrations.     

Spatial distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in the reservoir sediments after impoundment of Manwan Dam in the middle of Lancang River,China

Polycyclic aromatic hydrocarbons (PAHs) have received increasing attentions owing to their carcinogenicity, teratogenicity and environmental toxicity. The studies on the spatial variations, sources identification and potential ecological risk assessment of PAHs in the reservoir sediments after dam construction are becoming new hotpots. Sixteen PAHs contamination levels were investigated from 15 sample sections in the sediments of Manwan Reservoir in the middle of Lancang River, China. Total concentrations of 16 PAHs ranged from 14.4 to 137.7 ng g^?1 dw with a mean concentration of 70.68 ng g^?1 dw. The areas with residential settlement at large tributaries and near dam had higher PAHs concentrations. In the sight of classification of PAHs pollution levels, the sediments of Manwan Reservoir could be considered as low to moderate PAHs polluted levels. One-way analysis of variance for spatial analysis revealed that there were no significant differences (P < 0.05) for 16 PAHs at the reservoir head, centre and tail. Moreover, no significant differences (P < 0.05) were found for most individual PAH at the mainstream and tributaries except that BaP showed significant differences (P < 0.05) in the mainstream and tributaries. According to the diagnostic ratios, the possible pollution sources of PAHs in Manwan Reservoir might be mixed, primarily including the petroleum source and coal combustion. As compared with sediment quality guidelines, the observed concentrations of PAHs in all sample sections did not exceed the effects range low (ERL) and the threshold effect level (TEL) values, suggesting that there were little harmful biological toxic effects on the aquatic organisms in Manwan Reservoir. The study provided a comprehensive overview on the PAHs contaminations on the reservoir sediments in the middle Lancang River, which may have an important significances on the international river management.     

Occurrence and spatial distribution of organic contaminants in sediments from Chinhae Bay, Korea

Persistent organic pollutants (POPs) were monitored in surface sediment of Chinhae Bay, Korea. Sum (Σ) concentration (minimum, maximum and average — ng/g dry weight) ranged: ΣBTs (ng Sn/g): 12, 1230, 221; ΣPAHs: 54, 632, 182; nonylphenol: 107, 207, 148; bisphenol A: 4.36, 135, 83; T-PCBs: 0.64, 18, 3.49; ΣDDT: 0.19, 7.36, 1.15; ΣCHL: 0, 0.49, 0.06; ΣHCH: 0.03, 0.36, 0.10. Among them BTs, PAHs, nonylphenol and bisphenol A were detected in all locations. Chlordanes, HCHs and DDTs were at low levels. Levels of tributyltin remained similar to levels in 1987-94. PAHs were within national average. Chinhae Bay derives its pollution from a) two poβible point sources, namely, industrial and urban activities from inner Masan Bay and shipping activities from Kohyon Bay; b) diffuse sources of various sorts. Spatial distribution and chemical composition of POPs together with their inter-relationships were investigated.     

Human health risk assessment and dietary intake of organochlorine pesticides through air,soil and food crops (wheat and rice) along two tributaries of river Chenab,Pakistan

To assess the organochlorine pesticides (OCPs) contamination and their probable hazardous effects on human health; cereal crops (wheat and rice; n = 28) agricultural soil (n = 28) and air (n = 6) samples were collected from Gujranwala division, Punjab Province, Pakistan. ∑OCPs concentration ranged between 123 and 635 pg m⁻³, 31 and 365 ng g⁻¹ (dw), 2.72 and 36.6 ng g⁻¹ (dw), 0.55 and 15.2 ng g⁻¹ (dw) for air, soil, rice and wheat samples, respectively. DDTs were the predominant over other OCPSs detected from screened samples while the source apportionment analysis suggested the new inputs of DDTs in the study area. EDI (estimated daily intake) of ∑OCPs through rice and wheat was found 39 and 40 ng kg⁻¹ day⁻¹, respectively. Hazard ratios (HRs) on the basis 95th percentile concentrations were exceeding the integrity for most of the investigated OCP in rice and wheat. The results revealed that there is a severe risk to the human population of the study area through consumption of contaminated cereal crops.     

Simultaneous effects of two fungicides (copper and dimethomorph) on their phytoremediation using Lemna minor

Effects of two fungicides, copper and dimethomorph ((E,Z)4-[3-(4-chlorophenyl)-3-(3-4dimethoxyphenyl) acryloyl] morpholine) on Lemna minor growth and phytoremediation were evaluated. The toxicity of copper and dimethomorph alone and in combination, was assessed by growth inhibition of L. minor cultures after 96 and 168 h. Copper had a severe impact on growth (max. inhibition: 90 % at 1,000 μg L^?1) while dimethomorph (as pure ingredient or formulated as Forum) did not (inhibition <45 % at 1,000 μg L^?1) after 168 h of treatment. When both chemicals were combined, synergism was observed after 96 h of exposure to copper and Forum. However, this interaction was a simple additivity after 168 h. Additivity was also observed when the pure active ingredient (dimethomorph) replaced Forum in the mixture of copper and dimethomorph at 96 and 168 h. L. minor showed an excellent performance in removing copper from the medium since after 96 h, 36, 60, and 76 % removal were reached for 10, 20, and 30 μg L^?1 of Cu respectively. Copper accumulated in the plants. The removal of copper increased with Forum concentration. After 96 h copper (10 μg L^?1 initial concentration) elimination increased from 36.39 ± 5.86–60.70 ± 6.06 % when Forum concentration increased from 0 to 500 μg L^?1. Accumulation of copper in plants was also increased by Forum but not by the active ingredient alone. Depuration of Forum by L. minor varied between 10 and 40 % after 96 h and it was generally more efficient than that of the pure ingredient. This depuration decreased in the presence of copper possibly due to the metal toxicity.     

Mercury bioaccumulation in Southern Appalachian birds,assessed through feather concentrations

Mercury contamination in wildlife has rarely been studied in the Southern Appalachians despite high deposition rates in the region. From 2006 to 2008 we sampled feathers from 458 birds representing 32 species in the Southern Appalachians for total mercury and stable isotope δ ¹⁵N. Mercury concentrations (mean ± SE) averaged 0.46 ± 0.02 μg g^?1 (range 0.01–3.74 μg g^?1). Twelve of 32 species had individuals (7 % of all birds sampled) with mercury concentrations higher than 1 μg g^?1. Mercury concentrations were 17 % higher in juveniles compared to adults (n = 454). In adults, invertivores has higher mercury levels compared to omnivores. Mercury was highest at low-elevation sites near water, however mercury was detected in all birds, including those in the high elevations (1,000–2,000 m). Relative trophic position, calculated from δ ¹⁵N, ranged from 2.13 to 4.87 across all birds. We fitted linear mixed-effects models to the data separately for juveniles and year-round resident adults. In adults, mercury concentrations were 2.4 times higher in invertivores compared to omnivores. Trophic position was the main effect explaining mercury levels in juveniles, with an estimated 0.18 ± 0.08 μg g^?1 increase in feather mercury for each one unit rise in trophic position. Our research demonstrates that mercury is biomagnifying in birds within this terrestrial mountainous system, and further research is warranted for animals foraging at higher trophic levels, particularly those associated with aquatic environments downslope from montane areas receiving high mercury deposition.     

Pharmacokinetic properties of albiflorin and paeoniflorin after oral administration of pure compound,Radix Paeoniae alba extract and Danggui-Shaoyao-San extract to rats

This study compared the pharmacokinetics of albiflorin (ALB) and paeoniflorin (PAE), respectively, after oral administration of ALB, PAE, Radix Paeoniae alba (RPA) extract, and Danggui-Shaoyao-San (DSS) extract to rats on separate occasions. Analytes were detected simultaneously with liquid chromatography-tandem mass spectrometry. Noncompartmental pharmacokinetic parameters were calculated. After oral administration of RPA and DSS extract to rats, ALB reached maximum concentrations of 4637 ± 2774 ng/ml (0.40 ± 0.14 h) and 226 ± 122 ng/ml (0.35 ± 0.14 h) and PAE reached maximum concentrations of 2132 ± 560 ng/ml (0.40 ± 0.14 h) and 143 ± 65 ng/ml (0.45 ± 0.11 h), respectively. Compared to the AUC_0 ? t value (1122 ± 351 and 722 ± 158 ng h/ml for ALB and PAE, respectively) after administration of monomers, larger AUC_0 ? t value of ALB (4755 ± 2560 ng h/ml) and PAE (2259 ± 910 ng h/ml) after administration of RPA extract and smaller AUC_0 ? t value of ALB (411 ± 118 ng h/ml) and PAE (242 ± 126 ng h/ml) after administration of DSS extract were obtained. The C _max, AUC, and K _el of ALB and PAE were remarkably increased (P < 0.05, 0.01 or 0.005) during oral administration of RPA extract in comparison to that of DSS extract.     

Single and interactive effects of the antifouling booster herbicides diuron and Irgarol 1051 on photosynthesis in the marine cyanobacterium, Arthrospira maxima

Diuron and Irgarol 1051 are widely used antifouling booster herbicides to control the growth of redundant algae on submerged structures. They pose serious threats to the marine ecosystem especially on the non-target algal species which is of serious environmental concern. In the present study, the acute (1 h) individual and joint toxicities of the foresaid herbicides were assessed in the economically important cyanobacterium Arthrospira maxima, using robotic chlorophyll a (Chl a) fluorescence imaging method. When tested individually, Diuron was found to be more toxic to photosynthesis than Irgarol 1051, with median effective concentration (EC₅₀) values of 4.96–9.51 μg L^?1 and 7.15–14.80 μg L^?1, respectively. The most sensitive endpoint was the effective quantum yield (Y (II)) of photosystem II (PSII) for Diuron and the relative maximum electron transport rate (rETR_max) for Irgarol 1051. Mixture toxicity of Diuron and Irgarol 1051 was evaluated based on a factorial design with two factors at two levels, considering Y (II) as the sensitive biomarker. There were additive effects when low concentration of Irgarol 1051 (6.5 μg L^?1) was mixed with high and low concentrations of Diuron (5 μg L^?1 and 2.5 μg L^?1, respectively), with ratio of inhibition (RI) being 1.07±0.17 and 0.92±0.13, respectively. In contrast, high concentration of Irgarol 1051 (13 μg L^?1) resulted in antagonistic effects when added to low and high concentrations of Diuron, showing RI values of 0.89±0.03 and 0.81±0.06, respectively. The observations presented here indicate the need of consideration of interactive mode of action in evaluating herbicide toxicities in natural waters.     

Metals loads into the Mediterranean Sea: estimate of Sarno River inputs and ecological risk

The metals pollution in the Sarno River and its environmental impact on the Gulf of Naples (Tyrrhenian Sea, Central Mediterranean Sea) were estimated. Eight selected metals (As, Hg, Cd, Cr, Cu, Ni, Pb and Zn) were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediment samples. Selected metals concentrations ranged from 0.32 to 1,680.39 μg l^?1 in water DP, from 103.6 to 7,734.6 μg l^?1 in SPM and from 90.7 to 2,470.3 mg kg^?1 in sediment samples. Contaminant discharges of selected metals into the sea were calculated in about 13,977.6 kg year^?1 showing that this river should account as one of the main contribution sources of metals to the Tyrrhenian Sea.     

Chronic exposure of river sediments to environmentally relevant levels of tetracycline affects bacterial communities but not denitrification rates

The effects of tetracycline (TC) at chronic sub-inhibitory exposure concentrations on benthic denitrification rates and bacterial communities were explored. River sediments were continuously exposed to different TC concentrations (0.5, 20 and 10,000 μg L^?1) for 2 weeks in flow-through reactors allowing denitrification and bacterial growth conditions. Bacterial communities were fingerprinted by Denaturing Gradient Gel Electrophoresis of 16S rRNA gene amplification products. Cultivable denitrifiers enriched from the sediment were tested for TC resistance (2–128 mg L^?1). Denitrification rates were unaffected by exposure to TC, regardless of concentration. In contrast, the bacterial community composition changed significantly from sub-inhibitory (ng-μg L^?1) to therapeutic (mg L^?1) exposure concentrations. Furthermore the cultivable denitrifiers showed a high TC sensitivity (<4 mg L^?1). Maintenance of efficient benthic denitrification rates, even at the highest level of TC exposure most likely originated from an adaptation of the autochthonous bacterial community where dominant species become those that acquire, or already have resistance to antibiotics.     

Renal Excretion and Accumulation Kinetics of 2-Methylbenzoylglycine in the Isolated Perfused Rat Kidney

The effect of protein binding on kidney function has been studied by investigating the renal accumulation and secretion of the hippurate analogue 2-methylbenzoylglycine in the isolated perfused rat kidney in the absence and presence of bovine serum albumin (BSA). Experiments were performed with either 2.5% pluronic or a combination of 2.2% pluronic and 2% BSA as oncotic agents; a wide concentration range (1–190 μg mL^?1) of 2-methylbenzoylglycine was studied. Tubular secretion appeared to be a function of the amount of unbound drug in the perfusate and was best described by a model consisting of a high and low affinity Michaelis-Menten term. Parameters obtained after the analysis of renal excretion data were maximum transport velocity for the high affinity site (T_M,H) = 3.0 ± 2.8 μg min^?1, Michaelis-Menten constant for tubular transport for the high affinity site (K_T,H) = 0.5 ± 0.8 μg mL^?1, maximum transport velocity for the low affinity site (T_M,L) = 250 ± 36 μg min^?1, and Michaelis-Menten constant for tubular transport for the low affinity site (K_T,L) = 62 ± 17 μg mL^?1. The compound accumulated extensively in kidney tissue, ratios up to 175 times the perfusate concentration were reached. Accumulation data were best analysed by a two-site model similar to the model used to describe renal excretion. Calculated parameters were theoretical maximum capacity of the high affinity site (R_M,H) = 26 ± 23 μg g^?1, affinity constant for renal accumulation at the high affinity site (K_A,H) = 0.2 ± 0.4 μg mL^?1, theoretical maximum capacity of the low affinity site (R_M,L)= 1640 ± 1100 μg g^?1 and affinity constant for renal accumulation at the low affinity site (K_A,L) = 60 ± 58 μg mL^?1. The very high accumulation in kidney tissue could be explained by active tubular uptake, mediated by the secretory mechanisms involved, and dependent on the amount of free drug in the perfusate. This study shows that anionic drugs, subject to active secretion, may reach high concentrations in tubular cells even at low plasma concentrations.     

Hormesis phenomena under Cd stress in a hyperaccumulator—Lonicera japonica Thunb

A hydroponic experiment was carried out to investigate possible hormetic response induced by cadmium (Cd) in a potential hyperaccumulator-Lonicera japonica Thunb. The results showed that Cd at low concentrations induced a significant increase in plant growth, leaf water content and content of photosynthetic pigments in L. japonica, but decreased them at high concentrations, displayed inverted U-shaped dose response curves, confirming a typical biphasic hormetic response. The U-shaped dose response curves were displayed in malondialdehyde (MDA) and electrolyte leakage in leaves at low doses of Cd, indicating reduce oxidative stress and toxic effect. The increase of superoxide dismutase (SOD) and catalase (CAT) activities was observed along with the increased Cd concentration, indicative of increase in anti-oxidative capacity that ensures redox homeostasis is maintained. After 28 days exposure to 10 mg L^?1 Cd, stem and leaf Cd concentrations reached 502.96 ± 28.90 and 103.22 ± 5.62 mg kg^?1 DW, respectively and the plant had high bioaccumulation coefficient (BC) and translocation factor (TF′). Moreover, the maximum TF value was found at 2.5 mg L^?1 Cd treatment, implying that low Cd treatment improved the ability to transfer Cd from medium via roots to aerial structures. Taking together, L. japonica could be considered as a new plant to investigate the underlying mechanisms of hormesis and Cd tolerance. Our results suggest that hormetic effects should be taken into consideration in phytoremediation of Cd-contaminated soil.     

Optimized supercritical fluid extraction and effect of ionic liquids on picroside I and picroside II recovery from Picrorhiza scrophulariiflora rhizomes

The supercritical carbon dioxide-assisted extraction (SC CO₂E) process was optimized for extracting picroside I and picroside II from Picrorhiza scrophulariiflora rhizomes. The picroside I and picroside II content was determined using validated LC–MS methodology. The response surface methodology (RSM) was employed to study quantitative effects of extraction parameters viz. operating pressure, temperature, modifier concentration and extraction time using Box–Behnken design. The experimental data were fitted to second-order polynomial equation using multiple regression analysis and analyzed using the appropriate statistical method. By solving the regression equation and analyzing 3D plots, the optimum extraction conditions were found to be: extraction pressure, 25 MPa; temperature, 40 °C; modifier concentration, 15 % and extraction time, 90 min. The effect of four different ionic liquids (IL) as a modifier additive has been investigated using optimized SC CO₂E conditions. None of the IL showed equivalent or enhanced recovery of analytes of interest. The conventional hot percolation of P. scrophulariiflora powder resulted in 23.69 ± 1.02 and 10.22 ± 0.71 mg g^?1 picroside I and II, respectively, after an extraction period of 6 h whereas SC CO₂E with methanol as modifier showed 33.14 ± 1.23 and 16.77 ± 0.82 mg g^?1 recovery of picroside I and II, respectively in 90 min. The comparison of yield and extraction time demonstrated that SC CO₂E using methanol as modifier is more efficient than conventional hot percolation method.     

Toxicity and critical body residues of Cd, Cu and Cr in the aquatic oligochaete Tubifex tubifex (Müller) based on lethal and sublethal effects

The aim of the present study was to estimate critical body residues (CBRs) of three metals [cadmium (Cd), copper (Cu), chromium (Cr)] in the aquatic oligochaete Tubifex tubifex based on lethal (LBR) and sublethal effects (CBR), and to discuss the relevance of the exposure to sediment for deriving CBR. Toxicity parameters (LC₅₀, EC₅₀, LBR₅₀ and CBR₅₀) were estimated for each metal by means of data on survival and on several sublethal variables measured in short-term (4 days), water-only exposures and in long-term, chronic (14 and 28 days) exposures using metal-spiked sediment. Sublethal endpoints included autotomy in short-term exposure, as well as reproduction and growth in chronic bioassays. LBR₅₀ and CBR₅₀ were 3–6 times higher in sediment than in water-only exposure to Cd and about 2–11 times higher for Cu, depending on the measured endpoint; however, for Cr these parameters varied only by a factor of 1.2. Cu and Cr LBR₅₀ and CBR₅₀ values in 96 h water-only exposure were very similar (survival 2.39 μmol Cu g^?1 dw, 2.73 μmol Cr g^?1 dw; autotomy 0.53 μmol Cu g^?1 dw, 0.78 μmol Cr g^?1 dw). However, in metal-spiked sediments, 28 d CBR₅₀ values for autotomy, reproduction and growth ranged 6.76–29.54 μmol g^?1 dw for Cd, 3.88–6.23 μmol g^?1 dw for Cu, 0.65 μmol g^?1 dw for Cr (calculated only on total number of young). Exposure conditions (time and presence/absence of sediment) seem to be influential in deriving metal CBR values of Cd and Cu, while appear to be irrelevant for Cr. Thus, CBR approach for metals is complex and tissue residue–toxicity relationship is not directly applicable so far.