Uptake and metabolism of carbamazepine (CBZ) by clam Ruditapes decussatus and its effects in biochemical responses

1. Laboratory experiments were carried out to assess uptake and metabolism of the epilepsy drug, carbamazepine and its consequent biological responses in marine clam (Ruditapes decussatus) a model non-target organism in ecotoxicology.

2. Clams were exposed to two nominal concentrations (C1?=?30?μg/L and C2?=?50?μg/L) of CBZ for a maximum period of 14 days. Analysis of CBZ and their metabolites in clam and water after exposure to two nominal concentrations of the pharmaceutical drug were performed using UPLC-HRMS analysis. CBZ accumulation reached an average tissue concentration of 1241.59 ng/g dw and 1664.33 ng/g dw at low and high nominal concentration, respectively.

3. Furthermore, a metabolite (3-hydroxy-CBZ) was detected in tissues indicating carbamazepine translocation and metabolism inside clam, suspect screening of CBZ glucuronides was also performed by accurate mass extraction but it could not be detected.

4. Activities of antioxidant enzymes superoxide dismutase, catalase and gluthatione-S-transferase generally increased. Change in the contents of glutathione, malondialdehyde and protein carbonyl were also studied.

5. Results indicated that the bioaccumulation of CBZ resulted in the changes of the antioxidant defense system and the production of ROS with the oxidative stress, ultimately induced alteration in lipid peroxidation and protein carbonyl.     

An ecotoxicological approach to microplastics on terrestrial and aquatic organisms: A systematic review in assessment,monitoring and biological impact

Marine and land plastic debris biodegrades at micro- and nanoscales through progressive fragmentation. Oceanographic model studies confirm the presence of up to ∼2.41 million tons of microplastics across the Atlantic, Pacific, and Indian subtropical gyres. Microplastics distribute from primary (e.g., exfoliating cleansers) and secondary (e.g., chemical deterioration) sources in the environment. This anthropogenic phenomenon poses a threat to the flora and fauna of terrestrial and aquatic ecosystems as ingestion and entanglement cases increase over time. This review focuses on the impact of microplastics across taxa at suggested environmentally relevant concentrations, and advances the groundwork for future ecotoxicological-based research on microplastics including the main points: (i) adhesion of chemical pollutants (e.g., PCBs); (ii) biological effects (e.g., bioaccumulation, biomagnification, biotransportation) in terrestrial and aquatic organisms; (iii) physico-chemical properties (e.g., polybrominated diphenyl ethers) and biodegradation pathways in the environment (e.g., chemical stress, heat stress); and (iv) an ecotoxicological prospect for optimized impact assessments.     

The accumulation study of 90Sr in fish from a fishpond of northern Taiwan

Three kinds of fish from a natural fishpond in the north of Taiwan were collected and analyzed in this study. The three species were non-predatory Ctenopharyn odon idellus, predatory Aristichthys nobilis and predatory Mylopharyngodon piceus. The activity concentrations of ⁹⁰Sr in bone and edible flesh of fish, as well as in water and soil of fishpond were measured by using the radiochemical analysis. Additionally, the concentration of stable calcium in fish bone, [Ca]_bone, and that of stable strontium in fish bone, [Sr]_bone, were measured by ICP-AES. From the results, the concentration factors of ⁹⁰Sr, CF(⁹⁰Sr), in fish bone was no statistic difference between non-predatory and predatory fish. Besides, the accumulation of ⁹⁰Sr in the non-predatory fish remarkably decreased with increasing the fish weight. As for the predatory fish, they both showed no statistically significant correlations between the ⁹⁰Sr activity concentration and the fish weight. Regarding the activity concentrations of ⁹⁰Sr in fish bone, all the fish were observed positively correlated with the measured [Sr]_bone.     

Polystyrene nanoplastics (20 nm) are able to bioaccumulate and cause oxidative DNA damages in the brain tissue of zebrafish embryo (Danio rerio)

Nano-sized plastic particles formed from both daily use plastics and its debris have become a potential health and environmental problem due to features such as transportation through food webs and maternal transfer. Although many studies on the toxicity of plastics exist more detailed and molecular studies are needed to evaluate and review the effects of plastics especially in nano-size range. For this purpose, we have microinjected polystyrene nanoplastics (PNP) (20 nm) to the zebrafish embryo, which is one of the best model organisms for developmental toxicity studies, to simulate intake with food or maternal. Survival, hatching and malformations evaluated during the experimental period (120 h). Moreover, we have aimed to put forth the presence of reactive oxygen species (ROS) and apoptosis signalling accumulation in the body in addition to bioaccumulation of PNP and immunochemical toxicity (8-OHdG) on the brain of zebrafish larvae at the 120th hour. According to results, it has been demonstrated that 20 nm diameter PNP can reach the brain and bioaccumulate there, moreover lead to oxidative DNA damage in the brain regions where it bioaccumulates. Here we have also imaged the PNP from a vertebrate brain via transmission electron microscopy (TEM) for the first time. As a result of these, it has been detected increasing mortality and prevailing abnormalities in addition to excessive ROS and apoptosis in especially the brain. As a conclusion, obtained data have suggested that precautions, on the use and contamination of the plastic product, to be taken during both pregnancy and baby care/feeding are important for the health of the baby in future.     

Heat-shock protein (HSP70) response in the eastern oyster,Crassostrea virginica,exposed to PAHs sorbed to suspended artificial clay particles and to suspended field contaminated sediments

Sediments are a potentially significant source of pollutants, containing not only organic contaminants but heavy metals as well. The heat shock protein response (HSP70 family) in the eastern oyster exposed to suspended clay particles spiked with polynuclear aromatic hydrocarbons (PAHs) and to suspended field contaminated sediments (SFCS) was investigated. In experiment 1, oysters were exposed to 1.0, 1.5 or 2.0 g suspended clay particles with concentrations of 65.6, 159.0 and 242 μg PAHs per g of wet clay particles, respectively, and sampled after 40 days. Controls were exposed to 0, 1.0, 1.5, and 2.0 g suspended unspiked clay particles. In experiment 2, oysters were exposed to 0, 1.0, 1.5, and 2.0 g SFCS and the HSP70 expression was determined after 5, 10, 20 and 40 days exposure. Oysters exposed to suspended clay particles spiked with PAHs showed a significant increase in HSP70 levels, while oysters exposed to 1.0, 1.5 or 2.0 g suspended unspiked clay particles did not show changes (P=0.78) in HSP70 levels compared to the group receiving 0 g clay particles. Exposure to the SFCS resulted in a significant increase in HSP70 as a function of exposure (P<0.001) and treatment (P=0.006). The response, however, was not dose dependent. Compared to the control group (0 g SFCS), groups exposed to 1.0, 1.5 and 2.0 g SFCS reached significantly higher levels in HSP70 at 40 days of exposure, with those exposed to 2.0 g SFCS expressing the highest levels. The HSP70 expression for each treatment showed fluctuations at various time intervals. No mortalities were recorded during the exposure experiments. The major contaminants in the SFCS were PAHs, heavy metals and polychlorinated biphenyls (PCBs). These results reveal that exposure to PAHs sorbed to clay particles and to SFCS induced a HSP70 response in the eastern oyster.     

Influence of intracellular toxin concentrations on cylindrospermopsin bioaccumulation in a freshwater gastropod (Melanoides tuberculata).

Scant information is available regarding the bioaccumulation of cylindrospermopsin (CYN) in aquatic organisms, particularly in invertebrates. This study examined toxin bioconcentration and bioaccumulation in the aquatic snail, Melanoides tuberculata, following exposure to freeze-thawed whole cell extracts and a live Cylindrospermopsis raciborskii culture containing CYN. Both bioconcentration and bioaccumulation were evident, but exposure to toxin in the freeze-thawed solutions resulted in minor tissue contamination compared with that resulting from live C. raciborskii exposure. Thus, whilst CYN uptake resulted from both extracellular and intracellular exposures, the availability of intracellular toxin was critical in affecting tissue CYN values. M. tuberculata did not bioconcentrate CYN into the shell. Bioaccumulation of the analog deoxy-CYN was also recorded. Knowledge of intracellular toxin concentrations may be critical in evaluating the bioaccumulation, ecological and human health risks associated with contaminated systems.     

Cyanobacteria and prawn farming in northern New South Wales, Australia--a case study on cyanobacteria diversity and hepatotoxin bioaccumulation

Harmful cyanobacteria pose a hazard to aquatic ecosystems due to toxins (hepatotoxic microcystins, nodularins, and cylindrospermopsin) they produce. The microcystins and nodularins are potent toxins, which are also tumor promoters. The microcystins and nodularins may accumulate into aquatic organisms and be transferred to higher trophic levels, and eventually affect vector animals and consumers. Prawn farming is a rapidly growing industry in Australia. Because information regarding effects of cyanobacteria at prawn farms was lacking, we examined diversity of cyanobacteria and toxin production plus bioaccumulation into black tiger prawns (Penaeus monodon) under both field (northern New South Wales, Australia, December 2001-April 2002) and laboratory conditions. Samples were analyzed for hepatotoxins using enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC).The maximum density of cyanobacteria (1 × 10⁶ to 4 × 10⁶ cells/l) was reached in April. Cyanobacteria encountered were Oscillatoria sp. (up to 4 × 10⁶ cells/l), Pseudanabaena sp. (up to 1.8 × 10⁶ cells/l), Microcystis sp. (up to 3.5 × 10⁴ cells/l), and Aphanocapsa sp. (up to 2 × 10⁴ cells/l). An uncommon cyanobacterium, Romeria sp. (up to 2.2 × 10⁶ cells/l), was also observed. Contrasting earlier indications, toxic Nodularia spumigena was absent. Despite that both Oscillatoria sp. and Microcystis sp. are potentially hepatotoxic, hepatotoxin levels in phytoplankton samples remained low (up to 0.5-1.2 mg/kg dw; ELISA) in 2001-2002. ELISA was found suitable not only for phytoplankton but prawn tissues as well. Enzymatic pretreatment improved extractability of hepatotoxin from cyanobacteria (nodularin from N. spumigena as an example), but did not generally increase toxin recovery from prawn hepatopancreas.There were slightly increasing hepatotoxin concentrations in prawn hepatopancreas (from 6-20 to 20-80 μg/kg dw; ELISA) during the study. Hepatotoxin concentrations in surface sediment remained low (<5 μg/kg dw; ELISA) throughout the study. Laboratory experiments indicated that prawn hepatopancreas, heart, and brain were primary organs for hepatotoxin bioaccumulation. Toxin concentration in other organs, including muscle, was less effective. Orally administered nodularin levels in hepatopancreas rapidly decreased from initial 830 to 250 μg/kg dw in 96 h. Similarly, concentration of microcystin-LR injected in prawns decreased from 130 to 30 μg/kg dw (hepatopancreas) in 2 h.These results demonstrate that potential risks caused by cyanobacteria in prawn farming (farmers, prawns, and consumers) were not substantial in 2001-2002. Although prawns may act as vectors for toxin transfer, they did not accumulate alerting amounts of hepatotoxins and were able to effectively detoxify them. Because bloom toxicity may vary, low-frequency toxin monitoring is recommended.     

Bioaccumulation and Chemical Form of Chromium in <Emphasis Type="Italic">Leersia hexandra</Emphasis> Swartz

The chromium bioaccumulation ability of Leersia hexandra was assessed and the chromium distribution in the deferent chemical forms in plant tissues was determined. The hydroponic experimental results indicated that the maximum chromium concentration in the dry leaf matter of Leersia hexandra reached 4302 mg kg⁻¹. Chromium treatment could significantly increase the proportions of oxalic integrated chromium in leaves and residue chromium in roots, which might be related to the high resistance and bioaccumulation capacity for chromium in Leersia hexandra. Xuehong Zhang, Jie Liu these authors contributed equally to this work.     

Assessing Accumulation and Biological Effect of Hydrophobic Organic Contaminants in Water Using Caged Japanese Medaka and Deployed Triolein-embedded Cellulose Acetate Membranes

Applicability of triolein-embedded cellulose acetate membrane (TECAM) to accumulation and potential biological effect assessment for hydrophobic organic contaminants (HOCs) was investigated compared with Japanese medaka. The results of field exposure showed that medaka and TECAMs accumulated contaminants in a similar pattern with good correlations between concentrations in medaka and TECAMs based on lipid weight for OCPs (r = 0.96, p = 0.01, n = 9) and PAHs (r = 0.73, p = 0.01, n = 13). Meanwhile, 2,3,7,8-TCDD equivalents (TEQs) of TECAM extracts detected by in vitro H4IIE cell bioassay corresponded well to hepatic EROD activities of exposed fish and TEQs of water samples. We concluded that TECAM could be utilized as a surrogate for biomonitoring organisms to assess the bioaccumulation of HOCs and potential biological effect.     

Elemental composition in mud crab Scylla serrata from Mahanadi estuary,India: In situ irradiation analysis by external PIXE

During the present study concentration of nine elements (K, Ca, Mn, Fe, Cu, Zn, Se, Br and Pb) in different tissues of mud crab Scylla serrata from Mahanadi estuary, India were determined by the external PIXE set up at Institute of Physics, Bhubaneswar, India. The study demonstrates the effectiveness of the technique in analyzing both soft and hard tissue samples from marine organisms and opens the door for non-destructive, multi-elemental analysis of tissue samples with a very little sample preparation by direct irradiation. This technique can be well utilized for analyzing the tissue samples for environmental, toxicological and nutritional purposes. The study also demonstrates the elemental concentrations from tissue samples of any crustaceans from Mahanadi estuary for the first time. Sex based difference in the elemental concentration of the mud crabs were marked, which may be related to the growth rate and other biological activities. No significant difference in the concentration of elements (Ca, Mn, Fe, Cu and Zn) in the tissues of juveniles and adults of respective sex is observed, which indicated the active regulation of these elements by S. serrata.