Impact of pesticide regulations on mortality from suicide by pesticide in China: an interrupted time series analysis.

Background: Pesticide bans and regulatory restrictions have been shown to be effective strategies for preventing suicide in several countries. Suicide and suicide by pesticides have decreased significantly in China over the past two decades. However, whether the reduction was associated with pesticide regulation is unknown. Methods: The monthly data on suicide and suicide by pesticide from 2006 to 2018 were obtained from China's Disease Surveillance Point (DSP) system. Information on China's pesticide regulations since 1970 was obtained from Pesticide Action Network International (PAN International), Joint Meeting on Pesticide Management Highly Hazardous Pesticides (JMPM HHP) lists, the website of the Ministry of Agriculture of China, Pesticide Information Network of China, and the Wan Fang database. Change point detection and policy analysis were combined to identify the time of any trend change breakpoint of suicide and suicide by pesticide. Interrupted time series analysis was used to investigate the pre- and post-breakpoint trends of monthly standardized rates in suicide and suicide by pesticide. Results: The standardized pesticide suicide rate decreased by 60.5% from 6.50 in 2006 to 2.56 per 100,000 in 2018. Larger declines were evident among people in urban areas (67.3%), female individuals (63.5%), and people aged 15-44 years (68.1%). The effect of policies banning highly hazardous organophosphorus pesticides (HHOP) [rate ratio (RR) = 0.993, 95% CIs (0.991-0.994)] in December 2008 and stopping domestic sales and use of paraquat aqueous solution (RR = 0.992, 95% CIs: 0.990-0.994) in July 2016 were more pronounced than regulating the paraquat-related products (RR = 1.003, 95% CIs: 1.002-1.004) in April 2012. Conclusion: Declines in suicide by pesticide in China occurred contemporaneously with regulatory bans and restrictions implemented on several pesticides, particularly in urban areas, among female individuals, and the relatively low age profile. These findings indicate the potential influence of these bans on trends of suicide by pesticides.

Potential exposure to clothianidin and risk assessment of manual users of treated soil.

BACKGROUND: Treated soil is the second most prevalent application technique for all registered pesticides in China. Some developing countries also adopt this method. However, the safety of this scenario has not been reported in the literature. Experiments were therefore conducted to assess exposure using standard whole-body dosimetry and air sampling methodologies. RESULTS: Dermal deposition was the main route of exposure in this scenario. The total dermal unit exposure (UE) of operators to clothianidin-treated soil was 51.7 mg kg-1 AI handled (SD = 20.59, n = 16), and hands accounted for 36%. Inhalation UE was 0.04 mg kg-1 AI handled (SD = 0.02, n = 4), negligible compared with dermal exposure. Using an NOAEL (no observed adverse effect level) of 10 mg kg-1 day-1 , the margin of exposure was 773, i.e. greater than 100. CONCLUSION: For the first time, the scenario of treated soil exposure was assessed and was found to pose less risk than conventional pesticide application. These results can be used as a reference in pesticide management. © 2017 Society of Chemical Industry.

Measurement of operator exposure to chlorpyrifos.

BACKGROUND: To date, no research has been conducted to establish exposure levels for occupational pesticide operators under typical use scenarios in China. Through surrogate skin techniques (the whole-body method), the authors monitored dermal and inhalation exposure of pesticide applicators in China. In addition, the exposure of pesticide mixers was analysed. RESULTS: The total dermal exposure of inexperienced and experienced applicators was respectively 4037 and 536 mg kg(-1) of active ingredient (AI) handled for application to maize that was <80 cm in height. The exposure level was highest on hands; the closer to the hands, the lower arms and the upper legs, the higher the exposure. The unit exposure of mixers differed according to the formulation; exposure to emulsifiable concentrate (EC) and oil-in-water emulsion (EW) was greater than exposure to wettable powder (WP) or wettable dispersible granules (WG). The unit exposure of mixers via inhalation was significantly greater than that of applicators when chlorpyrifos (48% EC) was used (P < 0.0001). CONCLUSIONS: The main objectives of this study were to provide an indication of the realistic exposure risk of mixers and applicators, and to contribute useful information for risk mitigation and management and epidemiological studies in China.

Risk assessment of chlorpyrifos on rice and cabbage in China.

Chlorpyrifos is a widely used organophosphorus insecticide in agricultural pest control. To understand the residue behavior of chlorpyrifos and to evaluate the dietary risk of chlorpyrifos residue in food in China, a number of residue studies were conducted on rice and cabbage. The supervised trial median residues (STMRs) for rice and cabbage were less than 0.010 and 0.227 mg kg⁻¹, respectively. Only 7.4% and 13.3% of acceptable daily intake (ADI) (0-0.01 mg kg⁻¹ bw) of chlorpyrifos is occupied by dietary daily intake to the Chinese adult and children, respectively, due to the consumption of rice and cabbage. These results on risk assessment were consistent with that of JMPR. Incorporation of market survey residue data gave a 5-fold reduction in the estimated exposures to chlorpyrifos. Concerning the acute exposure, the national estimated short-term intake (NESTI) represents 0.077% and 10.6% for rice and cabbage, respectively, of the acute reference dose (ARfD) (0-0.1 mg kg⁻¹ bw). The application of chlorpyrifos at the recommended dose on rice and cabbage is unlikely to pose any public health issues if it is applied according to the good agricultural practices (GAPs) established by each country.

A comparative study of micellar and microemulsion EKC for the analysis of benzoylurea insecticides and their analogs.

An investigation of the basic factors which govern the microemulsion EKC (MEEKC) and MEKC for the separation of four benzoylurea (BU) insecticides and their four analogs was carried out. In MEEKC, the separation of eight BU compounds was optimized by changing the microemulsion composition, such as concentration of SDS, octane, n-butanol, and isopropanol percentages, as well as capillary temperature. Separation optimization was also carried out for MEKC, showing that ACN and a high level of another additive gamma-CD were needed to achieve effective separation of these analytes. Although separation with baseline resolution was achieved by either MEEKC or MEKC methods, the separation selectivity resulting from the proposed MEEKC method was completely different from that of MEKC. In addition, analytical time in MEEKC was longer than that in MEKC, but in view of theoretical plate numbers, detection limits, and reproducibility, both methods were effective for the analysis of BU insecticides and their analogs.