Effects of Nitrite and Toxic <Emphasis Type="Italic">Microcystis Aeruginosa</Emphasis> PCC7806 on the Growth of Freshwater Rotifer <Emphasis Type="Italic">Brachionus Calyciflorus</Emphasis>

Over the last two centuries, anthropogenic activities have increased the nitrogen amount in aquatic ecosystems, which has resulted in increased occurrences of blooms of cyanobacteria. This study investigated the effects of nitrite and the cyanobacterium Microcystis aeruginosa on population growth in the rotifer Brachionus calyciflorus. The rotifer was treated for 12 days with nitrite alone (medium containing 0, 3, 6, 10 mg NO₂ ⁻ –N L⁻¹), M. aeruginosa alone (medium containing 0 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at 0, 3, 6, 10 mg NO₂ ⁻–N L⁻¹), and nitrite in combination with M. aeruginosa (medium containing 3, 10 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at corresponding nitrite concentrations). We observed that a nitrite concentration of 10 mg NO₂ ⁻–N L⁻¹ markedly inhibited the growth of B. calyciflorus; however, rotifer growth declined slightly in the presence of M. aeruginosa precultured at 6 mg NO₂ ⁻–N L⁻¹. Furthermore, reduced population growth of B. calyciflorus was observed when it was treated with both nitrite and M. aeruginosa compared to nitrite alone or M. aeruginosa alone. These results suggested that a high tolerance of B. calyciflorus to nitrite levels may be attributed to the absence of specific respiratory structures and pigments; and that the increased toxicity of nitrite in combination with M. aeruginosa may have been due to increased production of microcystin. It is also possible that nitrite and microcystin could act in a synergistic way in causing toxicity.     

A New Developmental Toxicity Test for Pelagic Fish Using Anchoveta (<Emphasis Type="Italic">Engraulis ringens</Emphasis> J.)

A series of six 96-h static bioassays were performed to validate the use of anchoveta (Engraulis ringens) embryos as test organisms for ecotoxicological studies. The standardization protocol utilized potassium dichromate (K₂Cr₂O₇) as a reference toxicant and egg mortality as the endpoint. The results indicated that the mean sensitivity of anchoveta embryos to potassium dichromate was 156.1 mg L⁻¹ (range: 131–185 mg L⁻¹). The statistical data analysis showed high homogeneity in LC50 values among bioassays (variation coefficient = 11.02%). These results demonstrated that the protocol and handling procedures implemented for the anchoveta embryo bioassays comply with international standards for intra-laboratory precision. After secondary treatment, an effluent from a modern Kraft pulp mill was tested for E. ringens embryo toxicity, finding no significant differences from the controls.     

Impact of Elevated CO<Subscript>2</Subscript> and O<Subscript>3</Subscript> Concentrations on Biogenic Volatile Organic Compounds Emissions from <Emphasis Type="Italic">Ginkgo biloba</Emphasis>

In natural environment with ambient air, ginkgo trees emitted volatile organic compounds 0.18 μg g⁻¹ h⁻¹ in July, and 0.92 μg g⁻¹ h⁻¹ in September. Isoprene and limonene were the most abundant detected compounds. In September, α-pinene accounted for 22.5% of the total. Elevated CO₂ concentration in OTCs increased isoprene emission significantly in July (p < 0.05) and September (p < 0.05), while the total monoterpenes emission was enhanced in July and decreased in September by elevated CO₂. Exposed to elevated O₃ increased the isoprene and monoterpenes emissions in July and September, and the total volatile organic compounds emission rates were 0.48 μg g⁻¹ h⁻¹ (in July) and 2.24 μg g⁻¹ h⁻¹ (in September), respectively. The combination of elevated CO₂ and O₃ did not have any effect on biogenic volatile organic compounds emissions, except increases of isoprene and Δ3-carene in September. Foundation item: The National Natural Science Foundation of China (No. 90411019).     

Effect of Copper on Growth and Enzyme Activities of Marine Diatom, <Emphasis Type="Italic">Odontella mobiliensis</Emphasis>

The 72-h IC₅₀, 7-d no observable effect concentration (NOEC), low observable effect concentration (LOEC), Chronic values were derived for copper on the growth of marine diatom, Odontella mobiliensis. The effect of copper was also studied on cell morphology, size, nitrate reductase and antioxidant enzymes (Catalase, Superoxide dismutase and peroxidase). The 72-h IC₅₀ of 298.4 ± 28.3, NOEC of 15.6, LOEC of 29.6 and chronic value of 21.5 μg Cu L⁻¹ were found in the present study. The chlorophyll a was significantly decreased with increasing concentrations of copper. The length of the cell (apical axis) was extended from 30.14 ± 5.98 μm at control to 71.4 ± 6.29 μm at 574 μg Cu L⁻¹, the spines were absent at 574 μg L⁻¹ and the cell structure was entirely damaged at 926 μg Cu L⁻¹. The antioxidant enzymes viz. Catalase, Peroxidase activities and Melondialdehyde were increased whereas the Nitrate reductase and activity was reduced at 21.5 μg Cu L⁻¹ during 7 days exposure.     

The Effect of some Selected Pesticides on the Growth and Reproduction of Fresh Water <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>, <Emphasis Type="Italic">Chrysicthys nigrodigitatus</Emphasis> and <Emphasis Type="Italic">Clarias gariepinus</Emphasis>

Studies were carried out to determine the toxicity of some selected pesticides on fresh water fish in a tropical environment. The uptake of the pesticides lindane, pentachlorophenol (PCP), and propoxur, which are frequently used on farms, and in industries as well as by loggers and timber men on wood were studied in concrete ponds at the University of Cape Coast, in Ghana. The fish used for the study were Oreochromis niloticus, Clarias gariepinus, and Chrysicthys nigrodigitatus. They were obtained from cultured ponds in the Cape Coast and Mankessim districts in the Central Region and Weija Dam, in the Greater Accra region of Ghana. Single high lethal concentration (SD) or acute treatment and cumulative/chronic (or multiple minor) lethal concentration (CD) treatment were employed in administering the pesticides to the fish via water. Gas chromatograph electron capture detector analysis was done on the dead fish to see the extent of ingestion. The LC₅₀ values obtained for lindane on the three fish samples were as follows: Chrysicthys – 0.38 mg L⁻¹; Oreochromis – 0.42 mg L⁻¹, and Clarias – 1.2 mg L⁻¹. Mortalities occurred in fish within 3–5 days of application. For the PCP on Chrysicthys, Oreochromis, and Clarias species the LC₅₀ values were 0.42, 0.32 and 0.64 mg L⁻¹, respectively, for over a 2- to 3-day period. For a three-time influx period of propoxur the LC₅₀ for Chrysicthys, Oreochromis, and Clarias, were 22.0, 30.40, and 45.04 (all in mg L⁻¹), respectively. The results obtained indicated that the pesticides had adverse effects on the general growth and reproduction of fish as shown by gonadosomatic indices.     

Effects of Environmental Factors on the Uptake Rates of Dissolved Nitrogen by a Salt-water Green Alga (<Emphasis Type="Italic">Oocystis borgei</Emphasis> Snow)

Uptake rates for dissolved nitrogen (DN) by a marine alga (Oocystis borgei) were examined in a ¹⁵N tracer experiment. Maximal uptake rates for all forms of DN were observed at temperatures between 25 and 30°C and at algal concentrations between 3.22 × 10⁸ and 4.78 × 10⁸ cell L⁻¹. Light intensity required to achieve the maximal uptake rate was 45 μmol m⁻² s⁻¹ for dissolved inorganic nitrogen (DIN = NO₃ ⁻, NO₂ ⁻, NH₄ ⁺) and methionine, and 126 μmol m⁻² s⁻¹ for urea. Salinity required to achieve the maximal uptake rate was 12.85 ppt for DIN, 19.89 ppt for urea and 26.2 ppt for methionine.     

Bioremediation of Eutrophicated Water by <Emphasis Type="Italic">Acinetobacter Calcoaceticus</Emphasis>

Removal of phosphorus and nitrogen from eutrophicated water was carried out by in situ bioremediation. With the addition of Acinetobacter calcoaceticus, 65.0% ± 4.0% of total phosphorus (TP), 37.0% ± 4.0% of total nitrogen (TN), 75.0% ± 7.0% nitrite (NO₂ ⁻–N), and 87.0% ± 4.0% of ammonia (NH₄ ⁺–N) were removed. Furthermore, chlorophyll a removal in the inoculated treatments reached 83.7% ± 1.5%, and algae in the water was basically controlled.     

Protective Effect of High Alkalinity Against the Deleterious Effects of Chronic Waterborne Cadmium Exposure on the Detection of Alarm Cues by Juvenile Silver Catfish (<Emphasis Type="Italic">Rhamdia quelen</Emphasis>)

The objective of the present study was to analyze the effect of chronic cadmium (Cd) exposure at two alkalinity levels (63 and 92 mg l⁻¹ CaCO₃) on the antipredatory behavior of juvenile silver catfish (Rhamdia quelen) exposed to conspecific skin extract and predator odor. At an alkalinity of 63 mg l⁻¹ CaCO₃, 30 days of exposure to either 4.5 or 8.0 μg l⁻¹ Cd impaired the catfish’s antipredatory response to alarm cues. However, silver catfish exposed to 4.5 μg l⁻¹ Cd at an alkalinity of 92 mg l⁻¹ CaCO₃ responded to skin extract and predator odor. In catfish exposed to 8.0 μg l⁻¹ Cd at the same alkalinity, only the number of feeding bites decreased, and this occurred only for specimens exposed to predator odor. Our results show that higher alkalinity protected against the deleterious effects of Cd on alarm cue detection but only in the larvae exposed to the lowest waterborne Cd level.     

Selective Bactericidal Potential of Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L. var. <Emphasis Type="Italic">japonica</Emphasis>) Hull Extract on <Emphasis Type="Italic">Microcystis</Emphasis> Strains in Comparison with Green Algae and Zooplankton

We examined the selective inhibitory potential of rice hull extract on the toxic cyanobacterium Microcystis aeruginosa, in comparison with inhibitory effects on two green algae (Ankistrodesmus convolutus and Scenedesmus quadricauda) and a zooplankton (Daphnia magna) species. The inhibitory effect of rice hull extract, measured by algal growth or zooplankton survival using four different concentrations of extract (1, 10, 100 and 1000 μg L⁻¹), was highest on Microcystis strains (average: 98%, range: 95%–99%), followed by D. magna (average: 22%, range: 10%–47%), A. convolutus (average: 20%, range: 16%–24%), and S. quadricauda (average: 8%, range: 0%–15%). Rice hull extract had only a small effect on the growth of the green algae and Daphnia, particularly in the range 1–100 μg L⁻¹, and the inhibitory effect was somewhat diminished even at the 1,000 μg L⁻¹ level, at the end of the experimental period, especially for Daphnia. Our study indicates that rice hull extract has a strong specific algicide potential when used to combat M. aeruginosa.     

Is the Cry1Ab Protein from Bacillusthuringiensis (Bt) Taken Up by Plants from Soils Previously Planted with Bt Corn and by Carrot from Hydroponic Culture?

The uptake of the insecticidal Cry1Ab protein from Bacillus thuringiensis (Bt) by various crops from soils on which Bt corn had previously grown was determined. In 2005, the Cry1Ab protein was detected by Western blot in tissues (leaves plus stems) of basil, carrot, kale, lettuce, okra, parsnip, radish, snap bean, and soybean but not in tissues of beet and spinach and was estimated by enzyme-linked immunosorbent assay (ELISA) to be 0.05 ± 0.003 ng g⁻¹ of fresh plant tissue in basil, 0.02 ± 0.014 ng g⁻¹ in okra, and 0.34 ± 0.176 ng g⁻¹ in snap bean. However, the protein was not detected by ELISA in carrot, kale, lettuce, parsnip, radish, and soybean or in the soils by Western blot. In 2006, the Cry1Ab protein was detected by Western blot in tissues of basil, carrot, kale, radish, snap bean, and soybean from soils on which Bt corn had been grown the previous year and was estimated by ELISA to be 0.02 ± 0.014 ng g⁻¹ of fresh plant tissue in basil, 0.19 ± 0.060 ng g⁻¹ in carrot, 0.05 ± 0.018 ng g⁻¹ in kale, 0.04 ± 0.022 ng g⁻¹ in radish, 0.53 ± 0.170 ng g⁻¹ in snap bean, and 0.15 ± 0.071 ng g⁻¹ in soybean. The Cry1Ab protein was also detected by Western blot in tissues of basil, carrot, kale, radish, and snap bean but not of soybean grown in soil on which Bt corn had not been grown since 2002; the concentration was estimated by ELISA to be 0.03 ± 0.021 ng g⁻¹ in basil, 0.02 ± 0.008 ng g⁻¹ in carrot, 0.04 ± 0.017 ng g⁻¹ in kale, 0.02 ± 0.012 ng g⁻¹ in radish, 0.05 ± 0.004 ng g⁻¹ in snap bean, and 0.09 ± 0.015 ng g⁻¹ in soybean. The protein was detected by Western blot in 2006 in most soils on which Bt corn had or had not been grown since 2002. The Cry1Ab protein was detected by Western blot in leaves plus stems and in roots of carrot after 56 days of growth in sterile hydroponic culture to which purified Cry1Ab protein had been added and was estimated by ELISA to be 0.08 ± 0.021 and 0.60 ± 0.148 ng g⁻¹ of fresh leaves plus stems and roots, respectively. No Cry1Ab protein was detected in the tissues of carrot grown in hydroponic culture to which no Cry1Ab protein had been added. Because of the different results obtained with different commercial Western blot (i.e., from Envirologix and Agdia) and ELISA kits (i.e., from Envirologix, Agdia, and Abraxis), it is not clear whether the presence of the Cry1Ab protein in the tissues of some plants under field condition and in carrot in sterile hydroponic culture was the result of the uptake of the protein by the plants or of the accuracy and sensitivity of the different commercial kits used. More detailed studies with additional techniques are obviously needed to confirm the uptake of Cry proteins from soil by plants subsequently planted after a Bt crop.     

Analysis of Pyrethroid Insecticides in <Emphasis Type="Italic">Chironomus dilutus</Emphasis> Using Matrix Solid Phase Dispersion Extraction

A matrix solid phase dispersion method was developed to detect eight pyrethroid insecticides in the aquatic invertebrate, Chironomus dilutus. A mixture of silica gel, diatomaceous earth and primary/secondary amino solid absorbents were selected as the dispersion matrix, while 7% ethyl ether in hexane was used as the elution solvent. Method detection limits for the target pyrethroids ranged from 0.46 to 4.4 μg kg⁻¹, and recoveries were 63.5%–124.0%, 43.7%–116.0% and 53.1%–93.1% at spiked levels of 5, 20 and 50 μg kg⁻¹, respectively. The developed method was used to assess pyrethroid residues in laboratory-exposed and field-collected C. dilutus.     

Role of Waterborne Copper on Survival,Growth and Feed Intake of Indian Major Carp, <Emphasis Type="Italic">Cirrhinus mrigala</Emphasis> Hamilton

The effect of copper on survival, growth and feed intake of Indian major carp, Cirrhinus mrigala (Hamilton) fry (0.92 ± 0.28 g) was studied for 60 days. Survival rates of the fish exposed to control (0.02), 0.10, 0.15 and 0.23 mg L⁻¹ copper were 100%, 83 ± 3%, 58 ± 6%, and 50 ± 4%, respectively. Average daily growth was significantly (p < 0.05) lower at 0.15 and 0.23 mg L⁻¹ of copper. There was almost no growth at 0.23 mg L⁻¹ of copper. Feed intake rates reduced significantly (p < 0.05) at all the copper treatments. The copper accumulation in the fish increased with increasing concentrations of the metal.     

Survival,Growth, and Body Residues of <Emphasis Type="Italic">Hyalella azteca</Emphasis> (Saussure) Exposed to Fipronil Contaminated Sediments from Non-Vegetated and Vegetated Microcosms

We assessed chronic effects of fipronil and metabolite contaminated sediments from non-vegetated and Thallia dealbata vegetated wetland microcosms on Hyalella azteca during wet and dry exposures. Mean sediment concentrations (ng g⁻¹) ranged from 0.72–1.26, 0.01–0.69, 0.07–0.23, and 0.49–7.87 for fipronil, fipronil-sulfide, fipronil-sulfone, and fipronil-desulfinyl, respectively. No significant differences in animal survival or growth were observed between non-vegetated and vegetated microcosms during wet or dry exposures. Mean animal body residue concentrations (ng g⁻¹) ranged from 28.4–77.6, 0–30.7, and 8.3–43.8 for fipronil, fipronil-sulfide, and fipronil-sulfone. Fipronil-desulfinyl was not detected in any animal samples.     

Characterization of Copper-Resistant <Emphasis Type="Italic">Agrobacterium</Emphasis> Isolated from Legume Nodule in Mining Tailings

A copper-resistant bacteria CCNWSX2332 was isolated from root nodules of Lespedeza cuneata growing in a gold mining tailing region in northwest of China. The specific growth rate of the strain was 0.62 μh⁻¹ in the presence of 2.0 mM Cu²⁺ in TY liquid media, and the maximum copper accumulation of whole cell reached 147.03 μM Cu²⁺ per gram (dry weight) after 4 h incubation. A partial sequence of the copper resistance gene copA was amplified from the strain, and the phylogenetic analysis based on 16S rDNA sequence showed that CCNWSX2332 belonged to Agrobacterium, and it had 100% similarity with Agrobacterium tumefaciens type strain IAM13129^T.     

Chlorpyrifos-Induced Toxicity in <Emphasis Type="Italic">Duttaphrynus melanostictus</Emphasis> (Schneider 1799) Larvae

This study investigates the effects of continuous exposure to a widely used organophosphate pesticide, chlorpyrifos, on survival, growth, development, and activity of larvae of the Asian common toad, Duttaphrynus melanostictus Schneider 1799. Larvae were continuously exposed to six different concentrations (1–1,500 μg l⁻¹) of commercial-grade chlorpyrifos for 14 days and monitored for 1 additional week. Chlorpyrifos at ≥1,000 μg l⁻¹ caused significantly high and dose-dependent mortality, and the weekly LC50_{7 day–21 day} values ranged from 3,003 to 462 μg l⁻¹. Larvae surviving exposure to ≥500 μg l⁻¹ chlorpyrifos showed significant growth impairment, delays in metamorphosis, and decreased swimming activity. Tail abnormalities were the most common morphologic deformity at concentrations of 1,000 and 1,500 μg l⁻¹ chlorpyrifos. The findings of the present study highlight the need to recognize the potential risk that agrochemicals pose to amphibians inhabiting agricultural landscapes in Sri Lanka and other Asian countries.     

Metal Concentrations in Two Bioindicator Fish Species, <Emphasis Type="Italic">Merlangius merlangus</Emphasis>, <Emphasis Type="Italic">Mullus Barbatus</Emphasis>, Captured from the West Black Sea Coasts (Bartin) of Turkey

The Black Sea is very vulnerable to originating from land based human activities and its health is equally dependent on the coastal and non-coastal states of its basin. Total concentrations of cadmium, copper, zinc, lead, nickel, aluminum, iron, manganese, boron and chromium concentrations were determined in Merlangius merlangus (whiting) and Mullus barbatus found in Amasra in the West Coast of the Black Sea (Turkey). The metal contents that were measured in head and muscle was expressed in μg g⁻¹ wet weight. On average, while the highest Fe (344.25 μg g⁻¹), Mn (10.35 μg g⁻¹), Cr (0.96 μg g⁻¹) and Al (76.77 μg g⁻¹) concentrations were measured in the heads of M. merlangus and the highest Zn (77.99 μg g⁻¹), Cu(8.53 μg g⁻¹), B (44.83 μg g⁻¹), Ni (1.96 μg g⁻¹), Cd (0.40 μg g⁻¹) and Pb (6.80 μg g⁻¹) concentrations were detected in the muscles of M. merlangus. There were significant differences between metal levels of muscles in these two species. In terms of permissible levels reported by WHO FAO and TSE, there is not any risk for human consumption for both M. merlangus and M. barbatus, for Pb.     

Toxicity Testing of Waterborne Mercury with Red Sea Bream (<Emphasis Type="Italic">Pagrus major</Emphasis>) Embryos and Larvae

Acute toxicity tests revealed that, in red sea bream (Pagrus major) embryos, 24 and 48 h LC₅₀ values of waterborne HgCl₂ were 67.3 and 39.1 μg Hg²⁺ L⁻¹. In larvae, 48, 72 and 96 h LC₅₀ values were 41.9, 36.1 and 34.8 μg Hg²⁺ L⁻¹, respectively. Sub-chronic toxicity tests indicated that mercury concentrations ≥20 μg Hg²⁺ L⁻¹ decreased hatching success, increased mortality and induced teratogenicity in embryos and larvae. The NOEC, LOEC and MATC values were 8.0, 16.3 and 11.4 μg Hg²⁺ L⁻¹ for hatching success, mortality and teratogenicity; while those were 27.0, 36.9 and 31.6 μg Hg²⁺ L⁻¹ for body length and specific growth rate, respectively.     

Effect of Titanium Dioxide Nanoparticles on Gamma-Ray Treatment of Phenol in Different Matrices: Implications in Toxicity Toward <Emphasis Type="Italic">Daphnia magna</Emphasis>

Gamma-ray treatment of phenol was studied in terms of both chemical degradation and toxicological change. About 90 % of phenol (5.0 × 10⁻⁴ M) in ultrapure water (UW) was eliminated by gamma-irradiation at a dose of 10 kGy, but acute toxicity was dramatically increased, particularly for dose of 1 kGy, due to the formation of more toxic by-products such as hydroquinone, benzoquinone, resorcinol and catechol. The addition of TiO₂ nanoparticles had little effect on the removal of phenol in UW, but substantially enhanced the mineralization of phenol compared with gamma-irradiation alone. Additionally, degradation of phenol by gamma-irradiation was inhibited in a wastewater effluent (WE) matrix, likely due to the presence of dissolved organic carbon (22.06 mg L⁻¹). Furthermore, lower concentrations of toxic by-products were generated both in WE and in the presence of TiO₂ nanoparticles, resulting in reduction of toxicity increase by gamma-irradiation. Meanwhile, the toxicity of gamma-ray treated phenol in WE was well estimated with simple summation of individual toxicity of phenol and by-products (R ² = 0.9678).     

Accumulation of Microcystins in Nile Tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis> L., and Effects of a Complex Cyanobacterial Bloom on the Dietetic Quality of Muscles

The aim of this study was to investigate the kinetics of accumulation and elimination of microcystins in the tissues of Nile tilapia (Oreochromis niloticus) and to evaluate the effect of cyanobacterial exposure on fish muscle quality (levels of total fat and ash, protein, dry matter and the composition of saturated, monounsaturated and polyunsaturated fatty acids). Fish were exposed for 28 days to a natural cyanobacterial bloom with total microcystin concentration around 1,200 μg g⁻¹ biomass dry weight. The hepatopancreas accumulated microcystins up to 350 ng g⁻¹ fresh weight, but concentrations in muscle were generally below the detection limit (2 ng g⁻¹ fresh weight). Following the exposure, fish were moved to the clean water, but only minor microcystin removal from the hepatopancreas was observed during a 4 week depuration period. Exposures of tilapia to the complex cyanobacterial bloom had only minor and temporary impacts on the investigated parameters of dietetic quality.     

Genotoxicity of Fenpropathrin and Fenitrothion on Root Tip Cells of <Emphasis Type="Italic">Vicia faba</Emphasis>

The genotoxicity of fenpropathrin and fenitrothion on root tip cells of Vicia faba was studied. The symptoms were investigated about the mitotic index, the micronucleus frequency and chromosomal aberration frequency of root tip cells of Vicia faba which were induced by different concentrations of fenpropathrin and fenitrothion (1 × 10⁻¹⁰–1 × 10⁻² g L⁻¹). Results showed that fenpropathrin and fenitrothion could induce the micronucleus of root tip cells of Vicia faba. It occurred in a dose-dependent manner. Peaks were observed at 1 × 10 ⁻⁶ g L⁻¹ fenpropathrin and 1 × 10⁻⁴ g L⁻¹ fenitrothion, and micronucleus frequency reached 14.587 ± 1.511‰ and 14.164 ± 1.623‰, respectively. From 1 × 10⁻¹⁰ g L⁻¹ to 1 × 10 ⁻⁶ g L⁻¹ fenpropathrin and 1 × 10⁻⁴ g L⁻¹ fenitrothion, the micronucleus frequency increased with the increase of the concentrations, but beyond this range, the micronucleus frequency decreased with the further increase of the concentrations. A similar trend was observed for mitotic index. Moreover, fenpropathrin and fenitrothion could induce various types of chromosome aberration, such as lagging chromosomes, chromosome fragment, chromosome bridge, multipolar, nuclear buds, karyorrhexis, etc.