氟喹诺酮污染对淡水水生环境的影响—综述

截至目前,环境中抗生素的行为及其对生态毒性的影响仍被忽视。这一课题的范畴是宽泛的,涉及到广泛的生物体,包括栖居在各种水生生态系统中的微生物,藻类,无脊椎动物和脊椎动物等。改变这种系统中任何一个组成的平衡破坏了整个系统的平衡。在人类和动物医学中,氟喹诺酮的制造和频繁使用引起了对微生物抗生素耐药性流行率增加的高度关注,而且,除此之外,通过各种途径进入环境生态系统的抗生素母体和代谢物化合物的归趋也引起了环境影响关注。相关研究集中在分析环境样品中氟喹诺酮的存留浓度,并且经常使用动物评估模型来测试急性毒性,但是仍然不清楚在水生环境中低水平慢性接触对生命形态的生态毒性影响中起什么作用。本综述的目的是评估氟喹诺酮在动物和人类医学中的使用水平,确定其传播的途径,突出在淡水环境中的生态毒理学影。
精选自Nicol Janecko, Lucie Pokludova, Jana Blahova, Zdenka Svobodova, Ivan Literak. Implications of fluoroquinolone contamination on the fresh water aquatic environment -A review. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2647–2656, November 2016. DOI: 10.1002/etc.3552
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3552/full
     

Acute hematological toxicity of ivermectin to juvenile Clarias gariepinus

Abstract

Acute behavioral and hematological toxicity of ivermectin to C. gariepinus juveniles were assessed under static conditions at concentrations of 9 to 25?µg L^?1 for up to 4?days. Juveniles were highly sensitive to ivermectin, with an LC50 of 15?µg L^?1, culminating in spasms and paralysis. The hematological responses of packed cell volume, hemoglobin and red blood cell count decreased when compared to the control while the white blood cell count showed a biphasic trend. The mean corpuscular volume and mean corpuscular hemoglobin showed a mixed trend, while mean corpuscular hemoglobin concentration increased with increase in the concentration of the drug. Lymphocytes and neutrophils were also significantly (p?<?.05) increased. Ivermectin did not elicit any significant changes in monocytes, basophils and eosinophils. The observed changes confirm that ivermectin negatively affected the health of the fish. Therefore, real-time monitoring for early warning is recommended.     

Predicting barrier passage and habitat suitability for migratory fish species

Fish migrate to spawn, feed, seek refuge from predators, and escape harmful environmental conditions. The success of upstream migration is limited by the presence of barriers that can impede the passage of fish. We used a spatially explicit modeling strategy to examine the effects of barriers on passage for 21 native and non-native migratory fish species and the amount of suitable habitat blocked for each species. Spatially derived physical parameter estimates and literature based fish capabilities and tolerances were used to predict fish passage success and habitat suitability. Both the fish passage and the habitat suitability models accurately predicted fish presence above barriers for most common, non-stocked species. The fish passage model predicted that barriers greater than or equal to 6 m block all migratory species. Chinook salmon (Oncorhynchus tshawytscha) was expected to be blocked the least. The habitat suitability model predicted that low gradient streams with intact habitat quality were likely to support the highest number of fish species. The fish passage and habitat suitability models were intended to be used by environmental managers as strategy development tools to prioritize candidate dams for field assessment and make decisions regarding the management of migratory fish populations.     

Occurrence, bioaccumulation and potential sources of polybrominated diphenyl ethers in typical freshwater cultured fish ponds of South China

To determine the potential input sources of polybrominated diphenyl ethers (PBDEs) to fish farming environments in South China, samples of seven various environmental matrices were collected from October 2006-September 2007. Tri- to deca-BDEs were detected in all samples analyzed, with mean concentrations (±standard deviations) at 5.7 ± 3.6 ng/L in pond water, 15 ± 11 ng/g dry wt. in pond sediment, 12 ± 3.8 ng/g dry wt. in bank soil, 21 ± 20 ng/g lipid wt. in fish, and 93 ± 62 ng/g lipid wt. in fish feeds. In addition, BDE-209 was the major constituent in all samples except fish and BDE-47 was predominant in fish samples. Relatively high abundances of BDE-49 were detected in all the samples compared to those in the penta-BDE technical products. Several bioaccumulation factors were evaluated. Finally, statistical analyses suggested that fish feed, as well as pond water at a lesser degree, may have been the major source of PBDEs in freshwater farmed fish.     

Copper oxide nanoparticles can induce toxicity to the freshwater shredder Allogamus ligonifer

Increased commercialisation of nanometal-based products augments the possibility of their deposition into aquatic ecosystems; this, in turn, may pose risks to aquatic biota and associated ecological functions. Freshwater invertebrate shredders mostly use microbially-colonized plant litter as food resource and play an important role in aquatic detritus food webs. We assessed lethal effects of nanoCuO on the shredder Allogamus ligonifer (Trichoptera, Limnephilidae) by determining the concentration that induced 50% of death (LC₅₀), and sublethal effects of nanoCuO on the feeding behaviour and growth of the shredder by exposing the animals to: (i) stream water supplemented with nanoCuO and microbially-colonized leaves, and (ii) stream water (without nanoCuO) and microbially-colonized leaves pre-exposed to nanoCuO. Results from acute lethal tests showed that the 96 h LC₅₀ of nanoCuO was very high (569 mg L⁻¹). In the absence of nanoparticles, leaf consumption rate was 0.27 mg leaf DM mg⁻¹ animal DM d⁻¹ and the shredder growth rate was 56 μg animal DM mg⁻¹ animal DM d⁻¹. A significant inhibition in leaf consumption rate (up to 47%) and invertebrate growth rate (up to 46%) was observed when shredders were exposed to the higher tested sublethal concentration of nanoCuO (75 mg L⁻¹) through either contaminated stream water or pre-contaminated food. The exposure to increased nanoCuO concentration via water or pre-contaminated food led to higher accumulation of copper in the larval body. Leached water-soluble ionic copper from the nanoCuO adsorbed or accumulated in the shredder (up to 10.2% of total Cu) seemed to influence the feeding behaviour and growth of the shredder.     

Bioaccumulation, depuration and biotransformation of 4,4'-dibromodiphenyl ether in crucian carp (Carassius auratus)

Polybrominated diphenyl ethers (PBDEs) are extensively used as a class of flame retardants and have become ubiquitous environmental pollutants. Significant biotransformation of some PBDEs via reductive debromination has been observed. However, little is known about the fate of lower brominated BDEs in fish. In this study, the tissue distribution, excretion, depuration and biotransformation of 4,4′-dibromodiphenyl ether (BDE 15) were investigated in crucian carp (Carassius auratus) which were exposed to spiked water solution at different concentrations for 50 d, followed by a 14-d depuration period. Bioaccumulation parameters were calculated and the results showed that BDE 15 was mainly concentrated in the gill and liver. In particular, five biotransformation products of BDE 15 in carp were identified using GC-MS/MS. Besides two debrominated metabolites, three of the metabolites were mono-OH-BDE 15, diOH-BDE 15 and bromophenol. Our results unequivocally suggested that BDE 15 oxidation did occur via the formation of hydroxylated (OH-) metabolites in crucian carp exposed in vivo. These findings will be useful for determination of the metabolic pathways of PBDEs in freshwater fish, especially about their oxidation metabolism.     

Short- and long-term patterns of ¹³⁷Cs in fish and other aquatic organisms of small forest lakes in southern Finland since the Chernobyl accident

We summarize the patterns of ¹³⁷Cs activity concentrations and transfer into fish and other biota in four small forest lakes in southern Finland during a twenty-year period following the Chernobyl accident in April 1986. The results from summer 1986 showed fastest accumulation of ¹³⁷Cs into planktivorous fishes, i.e. along the shortest food chains. Since 1987, the highest annual mean values of ¹³⁷Cs have been recorded in fish occupying the highest trophic levels, for perch (Perca fluviatilis) 13,600 Bq/kg (ww) and for pike (Esox lucius) 20,700 Bq/kg (ww). At the same time, activity concentrations of ¹³⁷Cs in crustacean zooplankton and Asellus aquaticus have ranged between 1000 and 19,500 Bq/kg (dw). In 2006, 5-28% of the 1987 ¹³⁷Cs activity concentration levels were still present in perch and pike. Since 1989 their ¹³⁷Cs activity concentrations in oligohumic seepage lakes have remained significantly higher than in polyhumic drainage lakes due to the increased transfer of ¹³⁷Cs into fish in the seepage lakes with lower electrolyte concentrations, longer water retention times and lower sedimentation rate.     

Bivalve mollusks in metal pollution studies: From bioaccumulation to biomonitoring

Contemporary environmental challenges have emphasized the need to critically assess the use of bivalve mollusks in chemical monitoring (identification and quantification of pollutants) and biomonitoring (estimation of environmental quality). Many authors, however, have considered these approaches within a single context, i.e., as a means of chemical (e.g. metal) monitoring. Bivalves are able to accumulate substantial amounts of metals from ambient water, but evidence for the drastic effects of accumulated metals (e.g. as a TBT-induced shell deformation and imposex) on the health of bivalves has not been documented. Metal bioaccumulation is a key tool in biomonitoring; bioavailability, bioaccumulation, and toxicity of various metals in relation to bivalves are described in some detail including the development of biodynamic metal bioaccumulation model. Measuring metal in the whole-body or the tissue of bivalves themselves does not accurately represent true contamination levels in the environment; these data are critical for our understanding of contaminant trends at sampling sites. Only rarely has metal bioaccumulation been considered in combination with data on metal concentrations in parts of the ecosystem, observation of biomarkers and environmental parameters. Sclerochemistry is in its infancy and cannot be reliably used to provide insights into the pollution history recorded in shells. Alteration processes and mineral crystallization on the inner shell surface are presented here as a perspective tool for environmental studies.     

Effects of nickel chloride and oxygen depletion on behaviour and vitality of zebrafish (Danio rerio, Hamilton, 1822) (Pisces, Cypriniformes) embryos and larvae

We examined acute (2 h exposure of 5-day-old larvae) and subchronic (exposure from fertilization up to an age of 11 days) effects of NiCl(2).6H2O on embryos and larvae of zebrafish (Danio rerio), both alone and in combination with oxygen depletion. The following endpoints were recorded: acute exposure: locomotory activity and survival; subchronic exposure: hatching rate, deformations, locomotory activity (at 5, 8 and 11 days) and mortality. In acute exposures nickel chloride (7.5-15 mg Ni/L) caused decreasing locomotory activity. Oxygen depletion (or=10 mg Ni/L resulted in delayed hatching at an age of 96 h, in decreased locomotory activity at an age of 5 days, and increased mortality at an age of 11 days (LC20=9.5 mg Ni/L). The observed LOEC for locomotory activity (7.5 mg Ni/L) is in the range of environmentally relevant concentrations. Since locomotory activity was already affected by acute exposure, this parameter is recommended to supplement commonly recorded endpoints of toxicity.     

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.