Identification of phase II in vivo metabolites of alkyl-anthracenes in rainbow trout (Oncorhynchus mykiss)

Metabolism of xenobiotics is a two-step process that increases the polarity of compounds to facilitate their excretion. In previous work, the major in vitro phase I metabolites of alkyl-anthracenes by rainbow trout (Oncorhynchus mykiss) CYP enzymes were shown to be predominantly ring hydroxylated metabolites. Here, we present the first report on the identification of in vivo phase II metabolites of alkyl-anthracenes in juvenile rainbow trout. Bile was collected from trout injected with individual alkyl-anthracenes with, in some cases, a co-injection of β-naphthoflavone (BNF). Some samples were digested with the β-glucuronidase enzyme to confirm the presence of glucuronide conjugates. The metabolites were separated using a water-acetonitrile gradient on a HPLC system equipped with a C₁₈ column and a UV-diode array detector. Trout with endogenous and BNF-induced enzymes produced the same metabolites, but higher concentrations of metabolites were detected after enzyme induction. Alkyl-anthracenes were metabolized predominantly on the rings as evidenced by the UV spectral analysis. Likewise, mass spectrometry and UV spectral analysis confirmed a predominance of glucuronide conjugates for all systems investigated.     

Trade-offs between elimination and detoxification in rainbow trout and common bivalve molluscs exposed to metal stressors

The purpose of this paper was to examine trade-offs between elimination and detoxification in rainbow trout and three common bivalve molluscs (clam, oyster, and scallop) exposed to cadmium (Cd), copper (Cu), and zinc (Zn) based on recent reported experimental data. We incorporated metal influx threshold with subcellular partitioning to estimate rate constants of detoxification (k_d) and elimination (k₂). We found that the relationships between k₂ and k_d were negative for rainbow trout and positive for bivalve molluscs. However, the relationships between k_d and % metal in metabolically detoxified pool were found positive for rainbow trout and negative for bivalve molluscs. Our results also indicated that rainbow trout had higher accumulation (∼60-90%) in metabolically active pool when exposed to essential metals of Cu and Zn and had only 10-50% accumulation in response to non-essential metal of Cd. Based on a cluster analysis, this study indicated that similarity of physiological regulations among study species was found between Cd and Zn. Our study suggested that detoxification can be predicted by an elimination-detoxification scheme with the known elimination rate constant. We concluded that quantification of trade-offs between subcellular partitioning and detoxification provides valuable insights into the ecotoxicology of aquatic organisms and enhances our understanding of the subcellular biology of trace metals.     

Evaluation of ABC efflux transporters genes expression in kidney of rainbow trout (Oncorhynchus mykiss) fed with melamine and cyanuric acid diets

Gene expression experiments were targeted in order to monitor the ABC efflux transporters, which is potentially involved in cellular detoxification/defense. Changes in expression levels of different ABC genes in kidney of Oncorhynchus mykiss fed with melamine and melamine + cyanuric acid enriched diets were recorded in both treated groups by mRNA ΔΔ_CT relative quantification method. Expression profiles of eight different ABC genes basically showed low alterations in melamine group and more consistent changes in melamine + cyanuric acid treated fish, compared with own control. In the last group ABCC2 gene over expression was the more evident alteration. These results suggest that ABC efflux system could be involved in mobilization of hydrophilic molecules in the forcing condition of chronic exposure.     

Identification and dose dependency of ibuprofen biliary metabolites in rainbow trout

The biotransformation of the anti-inflammatory drug ibuprofen (IBF) was studied by exposing rainbow trout (Oncorhynchus mykiss) to IBF via intraperitoneal (i.p.) injection, and via water at four (0.17, 1.9, 13 and 145 μg L⁻¹) exposure levels for 4 d. Following exposure, the bile was collected and analyzed by LC–MS/MS methods. The identification of the formed metabolites in i.p. injected fish bile was based on the exact mass determinations by a time-of-flight mass analyzer (Q–TOF–MS) and on the studies of fragments and fragmentation patterns of precursor ions by ion trap mass analyzer (IT-MS). In addition to unmetabolized IBF, several phase I and phase II metabolites were found in the bile. The main metabolites were acyl glucuronides and taurine conjugates of IBF and of hydroxylated IBFs. The bioconcentration factors (BCF_bile), defined as the ratio of the sum of IBF and its metabolites in fish bile to the concentration of IBF in water, was determined following enzymatic deconjugation and was found to range from 14 000 to 49 000. The highest BCF_bile was found at the lowest exposure concentration (0.17 μg L⁻¹). The results show that rainbow trout has a high capacity for biotransformation of IBF, and the exposure of fish to sub μg L⁻¹ concentrations of IBF can be determined by the analyses of the biliary metabolites of the compound.     

Detailed study on the levels of polychlorinated dibenzo-p-dioxins,polychlorinated dibenzofurans and polychlorinated biphenyls in Yusho rice oil

One bottle of Yusho rice oil was obtained from a Yusho family in 1998. The levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in the causal oil were investigated with two different approaches and the individual concentrations of all the 17 2,3,7,8-substituted PCDD/F and 14 coplanar PCB (Co-PCB) congeners were elucidated for the first time. The concentrations of PCDDs and PCDFs were found to be 0.60 and 8.8 ppm, respectively. For PCBs, more than 130 PCB peaks were observed and a total concentration of 850 ppm including 170 ppm of Co-PCBs was obtained. The toxic equivalents (TEQs) of PCDDs, PCDFs, and Co-PCBs were calculated to be 17, 470, and 120 ppb, respectively. The relative contribution of these classes to the total TEQ in Yusho oil is 3%, 77%, and 20%, respectively, indicating that PCDFs play a major role in the toxicity of Yusho oil. Furthermore, it was confirmed that 2,3,4,7,8-penta-CDF contributes 58% to the total TEQ, supporting the view that this compound is the principal causal agent in Yusho poisoning. It is noteworthy that the most toxic 2,3,7,8-tetra-CDD was newly discovered, although it contributes only 0.1% to the total TEQ. Based on our data, the smallest TEQ intake during the latent period was estimated to be 0.067 mg for Yusho patients. This value is about 60% of that previously reported, suggesting a lower minimum threshold level for the development of the toxic symptoms of Yusho.     

Effects of lead on the growth and delta-aminolevulinic acid dehydratase activity of juvenile rainbow trout, Oncorhynchus mykiss

Activity of delta-aminolevulinic acid dehydratase (ALA-D) in blood and organs is a biomarker of lead (Pb) contamination in fish. Because current methods cannot measure the bioavailability of Pb, this biomarker may predict exposure more accurately than analysis of Pb concentrations in water. Juvenile fish are generally more sensitive to Pb than adult fish, but due to their small size, analysis of ALA-D in blood and individual organs is difficult. By modifying the erythrocyte ALA-D procedure, we developed a method to measure ALA-D activity on the supernatant from the tissue homogenate of whole fish (juvenile rainbow trout, Oncorhynchus mykiss). Significant decreases in the activity of ALA-D in rainbow trout were observed after a 29-day exposure to 121 and 201 microg Pb liter(-1), but not after exposure to 29 or 48 microg Pb liter(-1). Pb also significantly reduced growth in fish exposed to 201 microg Pb liter(-1).     

Effects of regional differences in waste composition on the thermal formation of polychlorinated aromatics during incineration

Two artificial wastes (A and B) whose contents reflect regional differences in municipal solid waste composition, were used to investigate the thermal formation of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and naphthalenes (PCNs) during incineration. Flue gas samples were simultaneously collected at three ports in the post-combustion zone corresponding to flue gas temperatures of 400, 300, and 200 °C. The combustion of Waste B, which had a higher chlorine and metal content than Waste A, produced greater levels of highly-chlorinated homologues, as demonstrated by a higher degree of chlorination. The total concentrations of PCDDs, PCDFs, PCBs, and PCNs formed in the combustion of both wastes increased as temperature decreased along the convector. There were no significant differences in total concentrations between Waste A and Waste B combustion at specific temperatures, with exception of PCDFs at 400 °C. Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) modeling, used to evaluate the data for all compound groups, suggest that during flue gas quenching at temperatures of 400 °C low-chlorinated homologues are preferentially formed in the presence of copper, which is known to be a very active catalyst for this process. At 300 and 200 °C, the formation of highly-chlorinated homologues is favored.     

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in blood and breast milk collected from pregnant women in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), and non-dioxin-like PCBs in paired samples of blood and breast milk collected from 67 secundiparas in Sapporo City, Japan, and combined this data with those of the 30 secundiparas previously measured. The arithmetic mean total toxic equivalents (TEQ-WHO) concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the 97 secundiparous subjects were 3.0-23 (mean: 13, median: 14) and 2.7-20 (mean: 8.6, median: 8.5) pg TEQ g⁻¹ lipid, respectively. The sums of the concentrations of 56 non-dioxin-like PCB congeners that were measured in the subjects’ blood and breast milk were 16-326 (mean: 107, median: 100) and 12-252 (mean: 73, median: 67) ng g⁻¹ lipid, respectively. The partitioning ratios of individual congeners of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs from blood to breast milk in secundiparas were almost the same as those of primiparas that have been recently reported, suggesting that the partitioning ratios of these compounds from maternal blood to breast milk in women is little affected by delivery. Furthermore, the partition of PCB congeners with chlorine at the 2-, 3-, 4′-, and 5-positions or the 2-, 4-, 4′-, and 5-positions of the biphenyl ring from the blood to the breast milk tended to occur at a higher level than that of other congeners. In particular, the levels of tetraCB-74 and hexaCB-146 in the breast milk for both primiparous and secundiparous mothers were slightly higher than those in the blood.     

Depletion of selected polychlorinated biphenyl, dibenzodioxin, and dibenzofuran congeners in farmed rainbow trout (Oncorhynchus mykiss): a hint for safer fish farming

Farmed fish can be exposed to persistent organic contaminants--such as polychlorinated biphenyls (PCBs), dibenzodioxins (PCDDs), and dibenzofurans (PCDFs)--via feed, this eventually resulting in accumulation levels of health concern. To study the correlation between feed contamination, chemical accumulation in fish muscle (fillet), and chemical depletion, an all-vegetal base (or blank) feed was prepared and fortified with a commercial PCB mixture (Aroclor 1254) and six PCDD and PCDF congeners (namely, 2,3,7,8-T(4)CDD, 2,3,7,8-T(4)CDF, 1,2,3,7,8-P(5)CDD, 1,2,3,7,8-P(5)CDF, O(8)CDD, and O(8)CDF) to reproduce realistic low, medium, and high contamination levels. After a 1-month exposure, trout (Oncorhynchus mykiss) were fed with the blank feed and sacrificed every 0.5 months over a 3-month period from exposure end; fillet specimens were sampled at each time. In all groups, the average fish weight increased linearly through the observation period. The chemical diminishing patterns observed were due to the combined effect of clearance and growth dilution: for 10 PCB and four PCDD and PCDF congeners, patterns were described with an empirical one-compartment (fish muscle) model. The canonical pseudo-first-order kinetic equation used was also modified into the form C=[C(0)exp(-k(C)t)] (m(W)t+1)(-1) to distinguish between the contributions to depletion from clearance, exp(-k(C)t), and growth dilution, (m(W)t+1)(-1). Most mean clearance half-life (HL(C)) estimates appear to be greater than 4 months, in a number of cases reaching magnitudes well over 10 months or even negative, thus clearly indicating a non-negligible contribution from a second compartment. Based on means and their 95% confidence intervals, the depletion HL(D) estimates of the 14 selected congeners seem to be comprised between 1.2-3.4 and 1.0-5.0 months, respectively: these values, accounting for both clearance and growth dilution, provide an indication of the relevance of a blank feed as a management option to reduce the overall PCB, PCDD, and PCDF content in farmed trout. Due to a lack of bioaccumulation, O(8)CDD and O(8)CDF yielded no results for evaluation, whereas for many PCB congeners results were insufficient for empirical modelling.     

Dietary exposure of rainbow trout to 8:2 and 10:2 fluorotelomer alcohols and perfluorooctanesulfonamide: Uptake, transformation and elimination

The bioaccumulation of perfluorooctanesulfonamide (PFOSA) and two fluorotelomer alcohols (8:2 FTOH, 10:2 FTOH) by rainbow trout (Oncorhynchus mykiss) through dietary exposure, including depuration rates and metabolism was investigated. Concentrations in the spiked feed ranged from 10.9 μg g⁻¹ wet weight (wet wt) for PFOSA and 6.7 μg g⁻¹ wet wt for 8:2 FTOH to 5.0 μg g⁻¹ wet wt for 10:2 FTOH. Trout was fed at 1.5% body weight per day for 30 d and depuration was followed for up to 30 d following previously published dietary exposure protocols. Perfluorooctanesulfonate (PFOS) was the major perfluoroalkylsulfonate (PFSA) detected in fish following dietary exposure to PFOSA. Half-lives of PFOS and PFOSA were 16.9 ± 2.5 and 6.0 ± 0.4 d, respectively. A biomagnification factor (BMF) of 0.023 was calculated for PFOSA which indicates that dietary exposure to PFOSA does not result in biomagnification in the rainbow trout. PFOS had a BMF of 0.08. The fluorotelomer saturated acids (8:2 FTCA, 10:2 FTCA) and fluorotelomer unsaturated acids (8:2 FTUCA, 10:2 FTUCA) were the major products detected in rainbow trout following dietary exposure to 8:2 FTOH and 10:2 FTOH, respectively. Half-lives were 3.7 ± 0.4, 2.1 ± 0.5, 3.3, and 1.3 d for 10:2 FTCA, 10:2 FTUCA, 8:2 FTCA, and 8:2 FTUCA, respectively. Small amounts of perfluorooctanoate (PFOA) and perfluorodecanoate (PFDA) were also detected in the FTOH exposed fish.     

Occurrence and sources of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in surficial sediments of Lakes Superior and Huron

Concentrations and congener profile patterns of 2378-substituted PCDD/Fs and DLPCBs in offshore, nearshore and tributary sediments of Lakes Superior and Huron are reported, and spatial trends and source contributions assessed. PCDD/F concentrations ranged from 5 to 18 000 pg/g dw (Lake Superior) and 3 to 6100 pg/g dw (Lake Huron); DLPCBs ranged from 9 to 11 000 pg/g dw (Lake Superior) and 9 to 27 000 pg/g dw (Lake Huron). Our analysis indicated atmospheric deposition is a primary source to depositional areas of both lakes; however, greater PCDD/F and DLPCB concentrations were observed at several nearshore and tributary sites, and were attributed to corresponding land use in the watershed. Statistical analysis and pattern comparison suggested that industrial inputs mainly associated with wood treatment plants, pulp and paper mills, mining operations, and chlorine-based chemical manufacturing also contributed to contamination by PCDD/Fs and DLPCBs in certain nearshore and offshore areas of Lakes Superior and Huron.     

Spatial character of polychlorinated biphenyls from soil and respirable particulate matter in Taiyuan, China

As one of China’s great metropolises, Taiyuan is affected by heavy chemical industry and manufacture of chemical products, and faces pollution from polychlorinated biphenyls (PCBs). Therefore, this study was conducted to determine the PCB concentrations in various environmental media in Taiyuan. We collected 15 soil samples, 34 respirable particulate matter (PM) samples (17 of PM_2.5 and 17 of PM₁₀) from urban areas of Taiyuan, and measured a total of 144 PCB congeners (including some coeluting PCB congeners). The total PCB concentrations were 51–4.7 × 10³ pg g⁻¹ in soil, 27–1.4 × 10² pg m⁻³ in PM_2.5 and 16–1.9 × 10² pg m⁻³ in PM₁₀. Of the PCB homologues, the dominant PCBs detected in the various media were all tri-CBs. Soil was relatively the most polluted media. Furthermore, principal-component analysis revealed that the major PCB source in Taiyuan may be associated with the main commercial PCB through long-range transmission. Toxic equivalency (TEQ) concentrations (based on ten dioxin-like PCBs) ranged from N.D. to 5.9 × 10⁻³ pg-WHO TEQ g⁻¹ in soil, 2.0 × 10⁻⁴–3.4 × 10⁻³ pg-WHO TEQ m⁻³ and 1.0 × 10⁻⁴–1.2 × 10⁻³ pg-WHO TEQ m⁻³ in PM_2.5 and PM₁₀, respectively. In previous studies, PCBs were not a severe component of contaminant in Taiyuan; however, this study suggested there is a potential threat of human exposure to PCBs for residents of Taiyuan.     

Cadmium- and calcium-mediated toxicity in rainbow trout (Oncorhynchus mykiss) in vivo: interactions on fitness and mitochondrial endpoints

Rainbow trout were exposed to sublethal waterborne Cd (5 and 10 μg L⁻¹) and dietary Ca (60 mg g⁻¹), individually and in combination, for 30 d to elucidate the interactive effects and evaluate the toxicological significance of mitochondrial responses to these cations in vivo. Indices of fish condition and mortality were measured and livers, centers of metabolic homeostasis, were harvested to assess mitochondrial function and cation accumulation. All indices of condition assessed (body weight, hepatosomatic index and condition factor) were reduced in all the treatment groups. Mortality occurred in the Cd-exposed groups with dietary Ca partly protecting against and enhancing it in the lower and higher Cd exposure, respectively. State 3 mitochondrial respiration was inhibited by 30%, 35% and 40% in livers of fish exposed to Ca, Cd and Cd + Ca, respectively, suggesting reduced ATP turnover and/or impaired substrate oxidation. While the phosphorylation efficiency was unaffected, state 4 and state 4+ (+ oligomycin) respirations were inhibited by all the exposures. Mitochondrial coupling was reduced and transiently restored denoting partially effective compensatory mechanisms to counteract Cd/Ca toxicity. The respiratory dysfunction was associated with accumulation of both Cd and Ca in the mitochondria. Although fish that survived acute effects of Cd and Ca exposure apparently made adjustments to energy generation such that liver mitochondria functioned more efficiently albeit at reduced capacity, reduced fitness was persistent possibly due to increased demands for maintenance and defense against toxicity. Overall, interactions between Cd and Ca on condition indices and mitochondrial responses were competitive or cooperative depending on exposure concentrations and duration.     

Inhibitory Effects on Esterase Enzymes Buche and Ache in Rainbow Trout (Oncorhyncus mykiss) Produced by the Slow Release Insecticide Chitosan Diethyl Phosphate

The study on the toxicity of chitosan diethyl phosphate (ChDP), a controlled release insecticide, on the activities of butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) in rainbow trout exposed to this pesticide was carried out. It was found that ChDP reduced BuChE activity in O. mykiss by a factor of eight at 6 days, with high fluctuation to the end of the exposition time at 12 days. The in vitro analysis of brain AChE treated with ChDP and Phenamiphos showed that it was competitively inhibited by both organophosphates. The values obtained for K_m and V_max for the AChE-ChDP (K_m: 21.23 μ M; V_max: 43.10 μ mol/min/g) and AChE-Phenamiphos (K_m: 38.62 μ M; V_max: 38.91 μ mol/min/g) systems were relatively low compared to values of the AChE (control) system (K_m: 62.99 μ M; V_max: 63.29 μ mol/min/g). Results reported in this study confirmed that chitosan diethyl phosphate performs similarly to organophosphate pesticides, producing inhibition in cholinesterases in rainbow trout.     

Tissue distribution and effects on hepatic xenobiotic metabolising enzymes of 2,3,3',4,4'-pentachlorobiphenyl (PCB-105) in COD (Gadus morhua) and rainbow trout (Oncorhynchus mykiss)

2,3,3',4,4'-Pentachlorobiphenyl, PCB-105 (IUPAC no. 105) was orally administered twice with a 4-day interval between dosings (total dose 10 mg kg(-1) body weight) to gonadally immature cod and rainbow trout of both sexes. The fish were killed 9 and 17 days after the first treatment, and the effects of PCB-105 on hepatic xenobiotic metabolising enzymes were determined by examining the cytochrome-P450-dependent ethoxyresorufin-O-deethylase (EROD) and aldrin epoxidase activities, and the EROD-catalysing P450 1A1 protein by indirect enzyme-linked immunosorbent assay (ELISA). Glutathione S-transferase activity towards 1-chloro-2,4-dinitrobenzene was included. The hepatic levels of the compound were determined. In addition, the distribution patterns of radio-labelled PCB-105 were studied by whole-body autoradiography. In exposed rainbow trout EROD activity and P450 1A1 by enzyme linked immunosorbent assay (ELISA) were significant induced, while GST activity was significant reduced. Exposed cod did not show significantly different enzyme values from controls, but percentage fat in the liver was significantly reduced. The whole cod liver contained about 1000 times more PCB-105 than the corresponding trout liver, and on a fat-weight basis the PCB level was five to six times higher in cod liver than in the rainbow trout liver. The autoradiographical investigation revealed high concentrations of radiolabelled compound in the liver and the brain of cod, while in rainbow trout the radiolabel was mainly confined to extrahepatic fat depots. These results demonstrate that the mono-ortho chlorinated coplanar analogue, PCB-105, has a different distribution pattern in the two fish species and that the potential for induction of the hepatic xenobiotic metabolising enzyme system seems to be lower in the cod than in the rainbow trout.     

Distribution, source and risk assessment of polychlorinated biphenyls (PCBs) in urban soils of Beijing, China

The concentration of PCBs in urban soils of Beijing across six land types including business districts (BD), cultural and educational areas (CE), classical gardens (CG), public green (PG), residential areas (RA), and roadsides (RD) was investigated. The total concentrations of PCBs ranged from below method detection limit (M.D.L.) to 37.11 × 10⁻³ mg kg⁻¹ dry weight (mean: 11.70 × 10⁻³ mg kg⁻¹; median: 13.28 × 10⁻³ mg kg⁻¹), which was at a medium level compared with other cities around the world. In general, the levels of PCBs decreased from the center of Beijing city to the suburb, suggesting the increasing PCBs concentrations with the age of the urban area. For different types of land use, the highest level of PCBs was observed in CG soils which have the oldest age, and the homologue profiles were similar, which were predominated by lowly chlorinated congeners including di-, tri- and tetra-CBs. Principal component analysis indicated that local sources such as Aroclor 1016, 1242, and 1248 were important sources in addition to long-range transport of PCBs all over the world. Although the toxic equivalency (TEQ) concentrations of dioxin-like PCBs in all soil samples of Beijing were higher than those in other urban areas of China, they met the Canadian soil quality standard.     

Determination of chlorinated pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers in human milk from Bizerte (Tunisia) in 2010

Thirty persistent organohalogen compounds including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in breast milk samples (n = 36) of primipara and multipara mothers from Bizerte in 2010. The analytical procedure involved the application of liquid-liquid extraction and gas chromatography with electron capture detector (GC-ECD) or mass spectrometry detector (GC-MS) for identification and quantification. Organohalogen compounds were found in all the analyzed samples, with predominance of p,p′-DDE, p,p′-DDT, p,p′-DDD, HCB and PCBs. The mean concentration of ∑DDTs in breast milk was 1163.9 ng g⁻¹ lipid wt. The ratio of p,p′-DDE/p,p′-DDT was low, suggesting that there is fresh intake of commercial DDT products in Bizerte. The mean levels of HCB and PCB were 286.8 and 331.2 ng g⁻¹ lipid wt respectively. These results were compared with the levels obtained in a previous study carried out in the same area in 2003. A general decrease of ∑DDTs levels and an increase of PCB levels were observed. Among the 10 PBDE congeners evaluated, BDE-28, BDE-47, BDE-99, BDE-66, BDE-138, BDE-100, BDE-154, BDE-153, and BDE-183 were detected in the analyzed samples at different frequency. The total PBDE concentrations ranged from 2.5 to 22.6 ng g⁻¹ lipid wt in the samples, with a mean and median value of 10.7 and 9.8 ng g⁻¹ lipid wt respectively. To our knowledge, this is the first data of PBDEs in Tunisian human milk. The present study shows that age and parity are factors influencing the levels of some organohalogen compounds in human milk.     

Immunostimulating effects of Ginkgo biloba extract against toxicity induced by organophosphate pesticide,diazinon in rainbow trout,Oncorhynchus mykiss: innate immunity components and immune-related genes

The immunostimulating and therapeutic properties of Ginkgo biloba (GB) have always been the focus of traditional medicine over thousands of years. During last decade, special attentions were paid to use of GB in aquaculture to enhance fish health and survival. In the present study, we investigated for the first time the immunogenic effects of dietary GB against oxidative and toxicity induced by organophosphate pesticide, diazinon. In non-diazinon-exposed fish, the plasma total immunoglobulin, lysozyme activity, and peroxidase activity significantly elevated after 60-day experiment in fish supplemented with 1 and 2 g GB/kg diet (p < 0.05). The respiratory burst activity and complement activity significantly increased only in groups supplemented with 0.5 g GB/kg diet (p < 0.05). Furthermore, the peroxidase activity, total immunoglobulin, and lysozyme activity significantly declined in groups supplemented with 4 g GB/kg diet during feeding trial (p < 0.05). There were no significant differences in expression of interleukin 1 beta (IL-1β) and transforming growth factor beta 1 (TGF-β1) genes in kidney between control group (non-GB-supplemented fish) and GB-supplemented fish (p > 0.05). In diazinon-exposed fish, all immunity components significantly decreased during exposure in control and those fed 0.5 and 4 g GB/kg diet (p < 0.05). In fish fed 1 and 2 g GB/kg diet, no alternations were found in immunity components during exposure period (p > 0.05). In addition, diazinon induced the expression of IL-1β and TGF-β1 genes in control and fish fed 0.5 and 4 g GB/kg diet (p < 0.05). No significant changes were observed in expression of IL-1β and TGF-β1 genes in fish supplemented with 1 and 2 g GB/kg (p > 0.05). In conclusion, the results of the present study suggest an immunogenic role for dietary GB at optimum dietary levels (1–2 g GB/kg diet) against toxicity induced by diazinon. Nevertheless, GB at high dietary levels (4 g GB/kg diet) showed immunosuppressive effects, which makes it necessary to optimize its levels in diet.

     

Organochlorine pesticides and polychlorinated biphenyls in riverine runoff of the Pearl River Delta, China: assessment of mass loading, input source and environmental fate

A large-scale sampling program was conducted to simultaneously collect water samples at the eight major riverine runoff outlets of the Pearl River Delta (PRD), South China to assess the importance of riverine runoff in transporting anthropogenic pollutants from terrestrial sources to the coastal ocean. The concentrations of ∑₂₁OCPs (sum of 21 OCP components) and ∑₂₀PCBs (sum of 20 PCB congeners) were 2.57-41.2 and 0.12-1.47 ng/L, respectively. Compositional distributions of DDTs suggested the possibility of new input sources in the study area, but contributions from dicofol seemed considerably low. The annual inputs of ∑₂₁OCPs and ∑₂₀PCBs were 3090 and 215 kg, with those of total HCHs and DDTs being 1110 and 1020 kg, respectively. A mass balance consideration indicated that riverine runoff is the major mode carrying OCPs from the PRD to the coastal ocean, and the majority of OCPs is further dissipated to open seas.     

Toxic Effects of Crude Oil Combined with Oil Cleaner Simple Green on Yolk-sac Larvae and Adult Rainbow Trout Oncorhynchus mykiss (4 pp)

Background, Goal and Scope Cleaner CRYSTAL Simple Green (SG) was used for the cleanup of the oil spill in the Baltic Sea near Lithuania in 2001. No scientific data are available on the effects and consequences of its application for local aquatic life. The aim of this study was to determine and compare sublethal effects of a) solution SG; b) crude oil alone; c) SG in combination with oil on rainbow trout Oncorhynchus mykiss at different stages of its development in laboratory conditions.Methods Laboratory studies were performed on adult rainbow trout (4-day duration) and on yolk-sac larvae (25-day duration) evaluating their biological parameters. Concentrations of water-soluble and thin-dispersed fractions of petroleum hydrocarbons were measured using gas chromatography.Results and Discussion SG solution (0.5 mg/l) did not affect the survival of larvae and adult fish, and no significant changes were determined in respiratory parameters of the exposed larvae and adult fish. The most expressed alterations were found in morphological parameters (a decrease in the average body mass) of larvae and in haematological indices (a decrease in the leukocyte count) of adult fish at the end of the tests. Crude oil (1610 mg/l) did not affect the survival of adult fish during the 4-day exposure. An increase in larvae mortality rate (~ 36%) was recorded at the end of the tests. A significant decrease in the average body mass and heart rate of larvae as well as in gill ventilation frequency of larvae and adult fish were determined. SG combined with oil induced an increase in larval mortality &#61566; 46% of individuals died at the end of the tests. No mortality was recorded in adult fish. The average body mass and heart rate of larvae were significantly decreased. Marked changes were also found in respiratory parameters (gill ventilation frequency of larvae and adult fish significantly decreased, while “coughing” rate increased). A 1-day, 2-day exposure of fish to SG combined with oil induced a significant decrease in the leukocyte count of adult fish, which was also determined at the end of the tests. The augmentation of adverse impact could be explained by the data obtained from our studies. When SG was added into dilution water with crude oil the concentration of petroleum hydrocarbons in the mixture increased 3 ~ 4.5 times after 24 h and 96 h, respectively. Conclusions The comparative study of the effects of crude oil alone, SG and SG combined with oil showed that their toxic effects on fish differed. Oil combined with SG was found to be more toxic to fish (larvae and adults) than SG alone and oil alone. Fish at early stages of development (yolk-sac larvae) were more sensitive to the effects of the compounds studied than adults.Recommendations and Outlook To diminish the negative impact of oil spill cleanup using chemicals on aquatic ecosystems, it is recommended to carry out more comprehensive studies of their effects and after-effects in laboratory conditions using a wide scale of local aquatic organisms. The selected species of the most sensitive aquatic organisms should include those which are unable to escape the impact of combined action of oil and cleaners. Special attention should be directed to the research of effects of these pollutants on studied organisms at their most sensitive stages of life (reproduction, hatching, early stages of development), as after-effects of exposure to pollutants may be observed in future generations.