Combined toxicity of pyrethroid insecticides and heavy metals: a review

Environmental Chemistry Letters - Co-occurrence of pyrethroid insecticides and heavy metals in the environment may produce combined toxic effects that are higher or lower than toxic...     

Identification of protein biomarkers of mercury toxicity in fish

Bioaccumulative metals such as mercury are found in increasing amounts in fish and their consumers. In the region of the Madeira River, in the Brazilian Amazon, mercury (Hg) is a predominant contaminant in the aquatic ecosystem. There is therefore a need to find specific biomarkers of mercury toxicity in fish to monitor contaminations. Here, mercury-bound proteins were identified in the liver tissues of fishes Mylossoma duriventre and Brachyplatystoma rousseauxii. Mercury was quantified in liver tissue, pellets and protein spots by graphite furnace atomic absorption. Proteins were fractionated by two-dimensional polyacrylamide gel electrophoresis and identified by mass spectrometry with electrospray ionization. We identified nine proteins linked to mercury and that presented biomarker characteristics of mercury. Among the proteins identified, isoforms of parvalbumin, ubiquitin-40S ribosomal protein S27a, brain-specific angiogenesis inhibitor 1-associated protein 2-like protein 2 and betaine–homocysteine S-methyltransferase 1 are notable for having the molecular function of binding to metallic ions.     

Acute toxicity of the synthetic pyrethroid pesticide fenvalerate to some air breathing fishes

Lethal concentrations (LC₅₀) of a synthetic pyrethroid pesticide, fenvalerate, for three species of air breathing fish Clarias batrachus, Channa punctatus and Heteropneustes fossilis were determined under water and acetone soluble condition in the laboratory using the static bioassay procedure of the American Public Health Association (APHA,1995). Acetone soluble fenvalerate was found more toxic than the water-soluble fenvalerate irrespective of species and exposure periods. The LC₅₀ value upon 96 days exposure to acetone soluble fenvalerate for C. batrachus, Channa C. punctatus and Heteropneustes H. fossilis were 1.35, 1.0 and 0.65?µg?L^?1, respectively. It is concluded from the present study that fenvalerate is highly toxic even to the hardy air breathing fishes and the pesticide, when dissolved in water, remains photostable and active to render toxicity for long duration.     

Acute toxicity of oil dispersants to marine fish larvae

The acute toxicities of several oil dispersants to the larvae of haddock, herring, lemon sole, pilchard, plaice and sole were examined, the type and aromatic content of the solvent being the main factors influencing the toxicity. Newer (second generation) dispersants had much lower toxicities. Ageing of dispersant solutions led to a decrease in toxicity, which could be related to loss of aromatic compounds from solution. Temperature and salinity had only slight influence on toxicity. For all dispersants, differences of susceptibility between species were less than differences at different ages within a species. The larvae of all species showed a similar susceptibility when newly hatched, and susceptibility increased throughout the yolk-sac stage. The transition period from yolk reserves to an external food supply was most critical, for once larvae had established feeding, resistance increased until metamorphosis. The dispersants appeared to act largely as physical toxins causing, initially at least, a reversible narcosis. The implications of the results are discussed in relation to the use of dispersants at sea.     

Biomarkers as tools to assess the chronic toxicity of ammonia in the juvenile Mugil cephalus

With juvenile fish as the subject, the effects of low concentration ammonia on antioxidant system were studied using Mugil cephalus. Samples of gill and liver tissue were obtained from 0.35, 0.70, 1.5 and 3?mg/L ammonia groups at 0, 5, 10, 15 and 20 days of exposure, at which times the biomarkers were measured. Results showed that gill malondialdehyde (MDA) content exhibited an initial significant increase (p?≤?0.05) at unionised ammonia concentrations of 0.70, 1.5 and 3.0?mg/L on day 5, followed by subsequent declines, while liver MDA levels exhibited significant increases (p?≤?0.05) at unionised ammonia concentrations of 1.5?mg/L starting on day 10 and at 3.0?mg/L starting on day 5. With exposure to ammonia at different concentrations, Na⁺-K⁺-ATPase activity in liver and gill decreased over time. The Na⁺-K⁺-ATPase activity was negatively related to ammonia concentration from 0.70 to 3.0?mg/L. Overall, our results show that MDA and Na⁺-K⁺-ATPase, evaluated here as potential biomarkers of ammonia exposure, exhibited responses to sublethal concentrations of ammonia that were concentration dependent.     

Assessment of toxicity of two nitroaromatic compounds in the freshwater fish Cyprinus carpio

This study was conducted to evaluate the toxicological response of p-nitrotoluene and p-nitroaniline to the key fish species, Cyprinus carpio. A freshwater fish bioassay based on the 96 h LC ₅₀ was used to estimate the single and joint toxicity of the two chemicals. The toxicity of p-nitrotoluene was greater than that of p-nitroaniline based on 96 h LC ₅₀ values of 40.74 mg·L^?1 and 48.99 mg·L^?1, respectively. Both compounds had moderate toxicity toward Cyprinus carpio, and this toxicity increased with the exposure duration and concentration. Binary mixtures of the compounds were more toxic than the individual compounds at 96 h, and they acted upon partial addition. When the exposure time was longer, the toxicity increased for mixtures of compounds with the same concentration or toxicity. The results of this study suggest that exposure to a combination of these chemicals would result in a higher environmental risk in aquatic systems than exposure to either compound alone. Further research is needed to investigate the combined effects and sublethal toxicity of p-nitrotoluene and p-nitroaniline, since they are both still used in China.     

The toxicity of several oil-spill removers to some species of fish and shellfish

Increasing quantities of crude oil and oil products are now being transported by sea, and this has resulted in a greater risk of oil pollution of coastal waters and has increased the dangers to marine life and amenities. With this increase in oil pollution have come various methods of treatment, among the more successful of which have been the so-called oil-spill removers or detergents. The toxicity of 12 of these materials, more accurately known as solvent emulsifiers, was examined, using 4 marine species of shellfish. Using 2 of these test species the toxicities of 3 solvent emulsifiers were examined in more detail, particular attention being paid to the time of exposure at different concentrations required to cause death. The effect of crude oil mixed with these 3 materials was also examined. Details are also given of some preliminary experiments with solvent emulsifiers on larvae of the shore crab (Carcinus maenas) and the brown shrimp (Crangon crangon).     

Assessing the toxicity of chemical compounds associated with marine land-based fish farms: The use of mini-scale microalgal toxicity tests

Many chemicals that are currently used in aquaculture have not been evaluated with regard to their specific effects on the aquatic environment. In the present study, the toxic effects of several chemicals associated with land-based marine fish farming activities were assessed using two species of marine microalgae (Phaeodactylum tricornutum and Isochrysis galbana). Mini-scale toxicity tests were performed with six antibiotics (amoxicillin, ampicillin, flumequine, oxytetracycline, streptomycin and sulfadiazine) and two disinfectants (formaldehyde and hypochlorite). Amoxicillin and streptomycin did not exert toxic effects. Sulfadiazine was the most toxic chemical; the EC₅₀ values were 0.11 mg/L and 1.44 mg/L for P. tricornutum and I. galbana respectively. As expected, the disinfectants displayed high toxicity, and P. tricornutum was particularly sensitive to these compounds. Although the differences in microalgal sensitivity depended on the chemical considered, both species were highly sensitive to most of the compounds tested. We recommend the inclusion of mini-scale microalgal toxicity tests in environmental risk assessment (ERA) and environmental monitoring plans because they are cost-effective and rapid.     

Toxicity of the pyrethroid bifenthrin insecticide

Bifenthrin is a chiral synthetic pyrethroid insecticide that has been commonly used for agricultural and domestic pest control over the past decades. Due to its widespread application, residues of bifenthrin has been frequently detected in environmental media, residential areas and biota, thus posing potential risks to the health of wildlife and humans. In particular, bifenthrin exhibits high acute lethal toxicity to aquatic species, and it is the primary contributor to the toxicity of insecticides in waters. Additionally, bifenthrin can also cause sublethal toxic effects on various non-target organisms, including developmental toxicity, neurobehavioral toxicity, oxidative damage, immune toxicity and endocrine disrupting effects. Here we review recent studies about the fate of bifenthrin in the environment and biological systems, the toxicity of the chiral parent compound bifenthrin and the toxic effects of main metabolites. The adverse effects of bifenthrin, identified from both in vitro and in vivo studies, and the potential underlying mechanisms are presented. We discuss the enantiomeric difference in the toxicological effects of bifenthrin, since enantiomers of chiral compounds show different interactions with biological systems. Pyrethroid insecticides metabolites are not acutely toxic, but they have sublethal toxicity, such as endocrine disrupting effects and immunotoxicity. We provide emerging evidence for toxic effects of several main metabolites.     

开发心血管和神经发育指标作为鱼类胚胎毒性实验中的亚致死终点

黑头软口鲦的胚胎毒性实验(fish embryo toxicity, FET)是一个更加人性化的替代方法,因为年轻生物被认为在毒物暴露中受到的危害更小。FET实验草案没有包括毒性终点以预测亚致死有害结局,这限制了它的应用。研究者针对FET实验提出了亚致死毒性终点的开发以增进该方法的应用范围。本研究针对黑头软口鲦开发了用于以往未测定过的亚致死指标的方法(例如自主收缩频率和心率);考察了一些亚致死效应终点的响应情况,包括成长相关的(湿重、体长、生长相关基因表达),神经发育方面的(自主收缩频率和神经发育基因表达),心血管功能和发育(心包区面积、眼睛大小和心血管相关基因表达),这是指标均作为FET实验的额外指标,模式毒物为3,4-二氯苯胺。其中,体长、眼睛尺寸和心包区面积相比于其他终点响应更为敏感。建立长时间有害影响与这些终点变化的关系对全面评价这些指标的毒性预测能力十分必要。 精选自Julie C. Krzykwa, Alexis Olivas, Marlo K. Sellin Jeffries. Development of cardiovascular and neurodevelopmental metrics as sublethal endpoints for the fish embryo toxicity test. Environmental Toxicology and Chemistry,2018,37:2530-2541.
详情请见 https://doi.org/10.1002/etc.4212
     

Flow cytometric analysis of fish leukocytes as a model for toxicity produced by azadirachtin-based bioagrocontaminant

Azadirachtin is one of the most promising natural biopesticide used to overcome the hazardous effects of different organic pesticides and believed to be more environmentally friendly due to the unique nature of biodegradability. In the present study, the impact of no-observed-effect level (NOEL) dose of an azadirachtin-based bioagrocontaminant, Neemsheild, on the blood profile of Indian major carp, Labeo rohita, was examined. The 96-hr LC₅₀ value of Neemsheild was found to be 44.61 ppm. The total erythrocyte count (TEC), hematocrit (Hcrt), and Hb (hemoglobin) values showed a gradual decrease throughout the experimental period, whereas total leukocyte count (TLC) showed an initial increase followed by decline. Flow cytometric analysis subdivided the entire leukocyte population into four separate groups: thrombocytes together with small lymphocytes, monocytes, neutrophils, and basophils. The fluctuation in leukocyte subpopulation indicated an immunotoxicological effect due to azadirachtin. Clustering of different cell types and similarity percentage values were found to differ greatly from control. It was evident from the study that the cell population comprising small lymphocytes and thrombocytes indicated predominant changes as physiological response of fish to different doses of azadirachtin. Thus, flow cytometric analysis of leukocyte populations may be considered as a biomarker to assess fish toxicity.     

三种典型渔药对大型溞(Daphnia magna)的急性毒性及其关键环境影响因子分析

测试了三种典型渔药三氯异氰尿酸(Trichloroisocyanuricacid,TCCA)、叔丁基对羟基茴香醚(Butylatedhydroxyanisole,BHA)、盐酸环丙沙星(Ciprofloxacinhydrochloride,CPFX)对大型(Daphniamagna)的急性毒性。结果表明,对于大型的毒性由大到小的顺序为:三氯异氰尿酸,叔丁基对羟基茴香醚,盐酸环丙沙星,48hLC50分别为0.19mg·L-1,3.15mg·L-1和135.15mg·L-1。通过三因素三水平正交试验分析了主要环境因子pH值、硬度、腐殖酸对三种渔药对大型毒性的影响,发现pH显著影响TCCA的毒性,硬度显著影响CPFX的毒性,而BHA毒性受环境因素影响不显著。     

Ammonia modeling for assessing potential toxicity to fish species in the Rio Grande, 1989-2002.

Increasing volumes of treated and untreated human sewage discharged into rivers around the world are likely to be leading to high aquatic concentrations of toxic, unionized ammonia (NH3), with negative impacts on species and ecosystems. Tools and approaches are needed for assessing the dynamics of NH3. This paper describes a modeling approach for first-order assessment of potential NH3 toxicity in urban rivers. In this study daily dissolved NH3 concentrations in the Rio Grande of central New Mexico, USA, at the city of Albuquerque's treated sewage outfall were modeled for 1989-2002. Data for ammonium (NH4+) concentrations in the sewage and data for discharge, temperature, and pH for both sewage effluent and the river were used. We used State of New Mexico acute and chronic NH3- N concentration values (0.30 and 0.05 mg/L NH3-N, respectively) and other reported standards as benchmarks for determining NH3 toxicity in the river and for assessing potential impact on population dynamics for fish species. A critical species of concern is the Rio Grande silvery minnow (Hybognathus amarus), an endangered species in the river near Albuquerque. Results show that NH3 concentrations matched or exceeded acute levels 13%, 3%, and 4% of the time in 1989, 1991, and 1992, respectively. Modeled NH3 concentrations matched or exceeded chronic values 97%, 74%, 78%, and 11% of the time in 1989, 1991, 1992, and 1997, respectively. Exceedences ranged from 0% to 1% in later years after enhancements to the wastewater treatment plant. Modeled NH3 concentrations may differ from actual concentrations because of NH3 and NH4+ loss terms and additive terms such as mixing processes, volatilization, nitrification, sorbtion, and NH4+ uptake. We conclude that NH3 toxicity must be considered seriously for its potential ecological impacts on the Rio Grande and as a mechanism contributing to the decline of the Rio Grande fish community in general and the Rio Grande silvery minnow specifically. Conclusions drawn for the Rio Grande suggest that NH3 concentrations may be high in rivers around the world where alkaline pH values are prevalent and sewage treatment capabilities are poorly developed or absent.     

The toxicity of ammonia,nitrite and nitrate to the fish,Catla catla (Hamilton)

The acute toxicity of unionized ammonia; nitrite and nitrate to the Indian major carp Catla catla (Hamilton) was determined using static and continuous flow through systems for 24 hours. The median lethal concentration (LC50) values for 24 h of ammonia (NH3-N), nitrite (NO2-N) and nitrate (NO3-N) were 0.045 mg/l, 120.84 mg/l and 1565.43 mg/l in static test respectively and were 0.036 mg/l, 117.43 mg/l and 1484.08 mg/l in continuous flow through test respectively.     

Characteristics of dispersions and water-soluble extracts of crude and refined oils and their toxicity to estuarine crustaceans and fish

The quantitative hydrocarbon composition and behavior in seawater of water-soluble fractions (WSF) and oil-in-water dispersions (OWD) of 4 oils was investigated. Two crude oils, South Louisiana crude and Kuwait crude, and two refined oils, No. 2 fuel oil and bunker C residual oil, were used in these investigations. The WSFs of the crude oils had higher total oil-hydrocarbon concentrations and were richer in light aliphatics and single-ring aromatics than were the WSFs of the refined oils. The WSFs of the refined oils contained significantly higher concentrations of naphthalenes than did those of the crudes. The hydrocarbon composition of the aqueous phase of OWDs closely resembled that of the parent oils. Gentle aeration of the OWDs resulted in a loss of 80 to 90% of the aqueous hydrocarbons in 24 h. Alkanes disappeared from the dispersions more rapidly than aromatics. The WSFs and OWDs of the refined oils were considerably more toxic to the 6 test species than were those of the crude oils. The test species can be ranked according to increasing sensitivity to oil as follows: Cyprinodon variegatus, Menidia beryllina, Fundulus similus, Penaeus aztecus postlarvae, Palaemonetes pugio and Mysidopsis almyra. The results of this investigation are discussed in relation to the potential impacts of oil spills on the marine and estuarine environments.     

The distribution,metabolism and toxicity of 14c-DDT in model aquarium tanks with fish and sediment simulating a tropical marine environment

Studies conducted on the distribution, fate and metabolism of DDT in a model ecosystem simulating a tropical marine environment of fish, Gobious nudiceps, Lethrinus harak, Gobious keinesis, Gobious nebulosis and white shrimp (Panaeus setiferus), show that DDT concentration in the water decreases rapidly within the first 24?h. Rapid accumulation of the pesticide in the biota also reaches a maximum level in 24?h before gradually declining. The bioaccumulation factors calculated for the fish species (G. keinesis) and white shrimp (P. Setiferus) were 270 and 351, respectively, after 24?h. There was a steady build up of DDT residues in the sediment during the first 24?h which continued to a maximum concentration of 6.66?ng/g in the seawater/fish/sediment ecosystem after 3 weeks and 5.27?ng/g in the seawater/shrimps/sediment ecosystem after 2.7 days. The depuration of the accumulated pesticide was slow with only 54% lost in G. nudiceps within 3 days of exposure in fresh sea water. By contrast, depuration was fast in the white shrimp, which lost 97% of the accumulated pesticide under the same conditions. DDT was found to be toxic to two of the fish species (G. nebulosis and L. harak) and to white shrimp, and the degree of toxicity was dependent on the particular species. The 24?h LC₅₀ at room temperature for the fish species G. nebulosis and white shrimp was found to be 0.011 and 0.116?mg/kg, respectively. These levels are comparable to the ones recorded for the temperate organisms. Degradation of DDT to its primary metabolites, DDE and DDD, was found in all the compartments of the ecosystem with DDE being the major metabolite in the fish, shrimps and sediment, while in seawater, DDD dominated as the major metabolite.     

山东省农田土壤中拟除虫菊酯类农药污染特征与风险评价

在山东省范围内采集农田表层土壤样品91个,采用气相色谱法分析了7种拟除虫菊酯类农药(SPs)的含量和组成,分析了其分布特征,比较了大田土壤和大棚土壤中该类农药含量的差异,并评价了其生态风险.结果表明,7种拟除虫菊酯类农药总含量(∑_7SPs)范围在0.01—88.51μg·kg~(-1)之间,均值为5.65μg·kg~(-1).与国内其他地区农田土壤相比,山东省农田土壤中拟除虫菊酯含量处于中等偏低水平.山东省各地区的拟除虫菊酯含量存在差异,但组成相近,均是高效氯氟氰菊酯、联苯菊酯和氯氰菊酯的比例较高.部分地区大棚土壤中的含量高于大田土壤.风险评价结果表明,山东省农田土壤个别采样点中甲氰菊酯和高效氯氟氰菊酯具有生态风险,三分之一的采样点存在潜在生态风险,其余采样点不存在生态风险.     

Helpers in fish

Summary Field data show that in the cichlid fish Lamprologus brichardi conspecifics other than the reproducing pair help in brood care and territory maintenance. The expected degree of relatedness between helpers and the eggs or larvae they tend lies between 0.25 and 0.5, decreasing with the helper's age. This decrease might influence the point of time at which helpers depart. Five other endemic Lake Tanganyika cichlids showing rather similar helping behaviour are described.