Pesticides ; classification ; toxicity

OBJECTIVETo analyze the results of the first-stage toxicological evaluation of 1 502 pesticide samples.

METHODSThe classification of the 1 502 pesticide samples was analyzed, and the experimental results of the samples in different years were compared.

RESULTSMost of the 1 502 pesticide samples were insecticides, accounting for 52.5% of all, followed by bactericides and herbicides. In the 5 years, the proportion of biogenic insecticides showed a significant rising trend (χ² = 11.426, P < 0.05). The proportion of single pesticides was 65.8%; mixed pesticides accounted for 32.7%; original pesticides accounted for only 1.5%. From 2008 to 2012, most pesticides had low toxicity, regardless of the exposure route (via the mouth, skin, or respiratory tract). Acute oral and dermal toxicity tests showed that pesticides with moderate toxicity declined year by year (oral exposure χ² = 18.036, P < 0.01; dermal exposure χ² = 40.482, P < 0.01). There was a small proportion of pesticides with high toxicity. We did not detect any pesticide with extreme toxicity. Acute skin irritation and eye irritation test showed an upward trend in proportion of non-irritating pesticides (χ² = 77.110, P < 0.01; χ² = 12.693, P < 0.05), while the proportion of medium-irritation pesticides decreased significantly (χ² = 18.941, P < 0.01; χ² = 13.129, P < 0.05). Sensitization test showed that all samples were weak sensitizers.

CONCLUSIONThe major type of investigated pesticides was insecticide. Most samples were single pesticides, and there was a certain proportion of mixed pesticides. Novel pesticides such as bio-pesticides are the development tendency. The tested pesticides were mainly low-toxicity pesticides, with a certain proportion of medium- and high-toxicity pesticides. Personal protection should be strengthened during production and use of pesticides.

Animals ; Pesticides ; classification ; toxicity ; Toxicity Tests, Acute

Animals ; Humans ; Neurotoxins ; toxicity ; Pesticides ; toxicity ; Pyrethrins ; toxicity ; Toxicology

OBJECTIVETo establish the threshold of toxicological concern(TTC) approach and to apply it in the risk assessment of metabolites, degradation and reaction products of pirimicarb.

METHODSTTC decision tree approach based on Cramer classification was established and Lazar software was used to predict the genotoxicity of the seven transformation products of pirimicarb, namely, R34836, R34885, R35140, R31805, R34865, R16210 and R16192. Dietary exposure in general population as well as in six age population groups was estimated by using data from the Chinese National Nutrition and Health Survey and pirimicarb residue data from national chemical surveillance data in 2011. TTC decision tree approach was used for risk assessment and the exposure was compared with the corresponding TTC values.

RESULTSOf the seven transformations of pirimicarb active substance, namely, R34836, R34885, R35140, R31805, R34865, R16210 and R16192, the maximum dietary exposure of mean and large portion(P 97.5) were all belong to 2-6 age group. The mean exposures of the seven transformation products for 2-6 age group,were 0.0290, 0.0207, 0.0015, 0.0320, 0.0005, 0.6918 and 0.1274 µg/kg,respectively, and the corresponding P 97.5 exposures were 0.0817,0.0581,0.0042,0.0900,0.0014, 1.9459 and 0.3585 µg/kg. Besides, the mean and P 97.5 exposure of R16210 for 2-6 age group was the largest,which were 0.6918 and 1.9459 µg/kg, accounting for 46.12% and 129.73% of the TTC threshold,respectively.

CONCLUSIONTTC decision tree approach is a useful tool for prior screening and primary risk assessment of the transformation products of pesticide active substance.

Carbamates ; toxicity ; Food Contamination ; Humans ; Maximum Allowable Concentration ; Pesticide Residues ; toxicity ; Pesticides ; toxicity ; Pyrimidines ; toxicity ; Risk Assessment

We designed and fabricated a novel high throughput brain-on-chip with three dimensional structure with the aim to simulate the in vivo three-dimensional growth environment for brain tissues. The chip consists of a porous filter and 3D brain cell particles, and is loaded into a conventional 96-well plate for use. The filter and the particle molds were fabricated by using computer modeling, 3D printing of positive mold and agarose-PDMS double reversal mold. The 3D cell particles were made by pouring and solidifying a suspension of mouse embryonic brain cells with sodium alginate into a cell particle mold, and then cutting the resulting hydrogel into pieces. The loaded brain-on-chip was used to determine the neurotoxicity of pesticides. The cell particles were exposed to 0, 10, 30, 50, 100 and 200 µmol/L of chlorpyrifos or imidacloprid, separated conveniently from the medium by removing the porous filter after cultivation. Subsequently, cell proliferation, acetylcholinesterase activity and lactate dehydrogenase release were determined for toxicity evaluation. The embryonic brain cells were able to grow and proliferate normally in the hydrogel particles loaded into the filter in a 96-well plate. Pesticide neurotoxicity test showed that both chlorpyrifos and imidacloprid presented dose-dependent inhibition on cell growth and proliferation. Moreover, the pesticides showed inhibition on acetylcholinesterase activity and increase release of lactate dehydrogenase. However, the effect of imidacloprid was significantly weaker than that of chlorpyrifos. In conclusion, a novel brain-on-chip was developed in this study, which can be used to efficiently assess the drug neurotoxicity, pharmacodynamics, and disease mechanism by combining with a microtiterplate reader.
Animals ; Brain ; Chlorpyrifos/toxicity* ; Culture Media ; Mice ; Oligonucleotide Array Sequence Analysis ; Pesticides/toxicity*

A total of 33 pesticides have been banned from Chinese medicinal materials and decoction pieces(plants) according to Chinese Pharmacopoeia(2020 edition). According to the chemical structures, they are mainly divided into seven categories: organophosphorus compounds, organochlorines, carbamates, amidines, sulfonylureas, phenylpyrazoles, and ethers. These banned pesticides exhibit neurotoxicity, reproductive toxicity, immune system toxicity, teratogenicity, carcinogenesis, and mutagenesis, seriously damaging human and animal health. They affect not only the quality and safety of traditional Chinese medicines and resulting products, but also their competitiveness in the international market. Due to the numerous varieties of traditional Chinese medicines and their complex substrates, it is necessary to establish a universal and highly sensitive method for pesticide residue detection. This review systematically summarized the residual status, toxicity, and analytical methods of banned pesticides in traditional Chinese medicines, and forecasted the prospects of different analytical techniques, so as to provide reference for further safety and risk assessment of banned pesticide residues in traditional Chinese medicines, thus ensuring the safe production of traditional Chinese medicines.
China ; Drugs, Chinese Herbal/toxicity* ; Humans ; Medicine, Chinese Traditional ; Organophosphorus Compounds ; Pesticide Residues/toxicity* ; Pesticides/analysis*

Animals ; Blood Pressure ; drug effects ; Chlorpyrifos ; toxicity ; Hypothermia ; chemically induced ; physiopathology ; Pesticides ; toxicity ; Rats ; Rats, Inbred LEC

Administration, Inhalation ; Animals ; Female ; Male ; Pesticides ; analysis ; toxicity ; Rats ; Rats, Wistar

OBJECTIVETo investigate the effects of exposure of paraquat and maneb on the behavior, the morphology and electrical activity of the Substantia nigra and striatum, and to discuss the relationship between this two pesticides and Parkinson's disease.

METHODS37 rats were divided randomly into 3 groups: control group (n = 11), paraquat (10 mg/kg) group (n = 13) and combinative group of paraquat (10 mg/kg) and maneb (30 mg/kg) (n = 13), and were exposed twice a week for 6 weeks by intraperitoneal injection. The behavior of animals in the declined-plane, the vertical-grid and the open-field test were observed. The morphology of substantia nigral neurons were investigated by HE pathology. The spontaneous discharge of striatum neurons were recorded after exposure.

RESULTSCompared to the control group and the pre-exposure group, both the numbers of animals sliding down from the declined-plane and the latency of rats' moving on the vertical-grid significantly increased, and the animals' autonomic movement decreased significantly (P < 0.05, P < 0.001). After the combinative exposure, the neurons of the Substantial nigra pars compacta (SNPc) were progressively impaired, the cell density of the paraquat group [(82.17 ± 12.91) n/mm(2)] and the combined group [(41.15 ± 6.44) n/mm(2)] were lower than that in control group (143.10 ± 20.85 n/mm(2)] (P < 0.01). In the paraquat group (5.97 ± 7.30 Hz) and the combined group [(6.95 ± 9.87) Hz], the average discharge rates of the striatum neurons were increased significantly compared to the control group [(1.78 ± 5.05) Hz] (P < 0.01). The bursting discharge was increased significantly in the combined group (22.3%) compared to the control group (9.8%) and the paraquat group (5.6%) (P < 0.05, P < 0.01).

CONCLUSIONThe co-exposure of paraquat and maneb could induce similar symptoms to Parkinsonism syndrome of rats such as rigidity, moving reduction and etc, and the combined exposure had a certain enhanced effect compared to alone paraquat exposure. The combinative exposure of paraquat and maneb could cause neural loss in SNPc and it is involved with the enhanced electrophysiological activity in striatum. The synergy toxicity of paraquat and maneb in nigrostriatal system is related to Parkinson's disease.

Animals ; Corpus Striatum ; drug effects ; Male ; Maneb ; toxicity ; Paraquat ; toxicity ; Parkinsonian Disorders ; chemically induced ; Pesticides ; toxicity ; Rats ; Rats, Sprague-Dawley ; Substantia Nigra ; drug effects

The present article reviews the advances in the studies of male reproductive toxicity of the pesticides that are widely used and commonly researched in the recent years by means of animal experiment and human investigation. The mechanism of male reproductive toxicity of pesticides is discussed. And problems are raised in the evaluation of human reproductive hazards.
Animals ; Follicle Stimulating Hormone ; blood ; Genitalia, Male ; drug effects ; Humans ; Luteinizing Hormone ; blood ; Male ; Pesticides ; toxicity ; Spermatozoa ; drug effects