Propanil

Anaerobic Degradation of Propanil in Soil and Sediment Using Mixed Bacterial Culture

The widespread use of the herbicide, propanil, causes severe environmental problems. In this study, the effects of propanil on the bacterial community in a sediment slurry were determined. Moreover, the degradation of the herbicide by pure and mixed cultures was first conducted under anaerobic conditions. The results showed that propanil caused significant changes in the bacterial community under anaerobic conditions. Four bacterial strains, i.e., Geobacter sp. Pr-1, Paracoccus denitrificans Pr-2, Pseudomonas sp. Pr-3, and Rhodococcus sp. Pr-4, isolated from the an enrichment sediment slurry were the first pure cultures that degraded propanil and 3,4-dichloroaniline (3,4-DCA) under anaerobic conditions. Some individual isolates showed the slow degradation of propanil and 3,4-DCA, but the mixture of the four strains increased the degradation rates of both compounds. The mixed culture of these isolates transformed more than 90% of propanil within 10 days in liquid media with the amendment of dextrose, glucose, or acetate. The determination of degradation pathway showed that propanil was transformed to 3,4-DCA and some other products before degrading completely. This study provides valuable information on the effects of propanil on the bacterial community and the synergistic degradation of propanil under anaerobic conditions.

Peer review of the pesticide risk assessment of the active substance propanil

The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State Italy for the pesticide active substance propanil and the assessment of applications for maximum residue levels (MRLs) are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative use of propanil as a herbicide on rice. MRLs were assessed in rice. The reliable endpoints, appropriate for use in regulatory risk assessment and the proposed MRLs, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Biodegradation of propanil by Acinetobacter baumannii DT in a biofilm-batch reactor and effects of butachlor on the degradation process

The herbicide, propanil, has been extensively applied in weed control, which causes serious environmental pollution. Acinetobacter baumannii DT isolated from soil has been used to determine the degradation rates of propanil and 3,4-dichloroaniline by freely suspended and biofilm cells. The results showed that the bacterial isolate could utilize both compounds as sole carbon and nitrogen sources. Edwards's model could be fitted well to the degradation kinetics of propanil, with the maximum degradation of 0.027 ± 0.003 mM h-1. The investigation of the degradation pathway showed that A. baumannii DT transformed propanil to 3,4-dichloroaniline before being completely degraded via the ortho-cleavage pathway. In addition, A. baumannii DT showed high tolerance to butachlor, a herbicide usually mixed with propanil to enhance weed control. The presence of propanil and butachlor in the liquid media increased the cell surface hydrophobicity and biofilm formation. Moreover, the biofilm reactor showed increased degradation rates of propanil and butachlor and high tolerance of bacteria to these chemicals. The obtained results showed that A. baumannii DT has a high potential in the degradation of propanil.

Clinical characteristics, treatment and outcomes of acute propanil poisoning in a 7-year retrospective cohort study

The present study was a 7-year retrospective cohort study (2012-2018) of patients treated for acute propanil poisoning by ingestion, using data from Ramathibodi Poison Center, Thailand. The aim of this study was to describe the clinical characteristics, treatment, outcomes and factors associated with moderate to severe outcomes and death following acute exposure to propanil. The effect of administering multiple-dose activated charcoal (MDAC) on clinical outcomes was also evaluated. A total of 275 cases were included. The results show that two thirds of patients were male and mean age was 40 years. Patients ingested either propanil or a mixture of propanil and other herbicides. The majority (98%) of exposures was intentional. Most patients (65.5%) presented with gastrointestinal symptoms. Methemoglobinemia and hemolysis were observed in 108 patients (39.3%) and 25 patients (9.1%), respectively. Median time to onset of methemoglobinemia and hemolysis after propanil ingestion was 5.5 and 48 h, respectively. One hundred and forty-one patients (51.3%) were treated with MDAC, and some patients received methylene blue (21.5%), intubation (18.5%), or blood transfusions (8%). All patients were admitted to hospitals. The median length of hospital stay of patients who survived was 3 days. Multivariate analysis indicated that neurological symptoms at presentation, methemoglobinemia and acute kidney injury during admission, were associated with moderate to severe outcomes. Factors associated with mortality were older age, larger amount of ingestion, neurological symptoms at presentation and hypotension during admission. The overall mortality rate was 6.2%. The mortality rate was 3.6% in patients that received MDAC and 9% in patients that did not, although the difference was not statistically significant. Subgroup analysis of patients who developed methemoglobinemia or both methemoglobinemia and hemolysis found a statistically significant lower mortality rate in patients that received MDAC. In conclusion, methemoglobinemia and hemolysis contribute to poor outcomes in acute propanil poisoning. Age, amount of ingestion, neurological symptoms at presentation and hypotension during admission could prognosticate deaths, and patients with these factors should be closely observed and aggressively managed.

A New Treatment Approach for Acute Propanil Poisoning: A Case Report

Propanil is a widely used herbicide in agriculture and is also an important cause of poisoning in Sri Lanka. Incidence is around 2% and is commonly reported as self-poisoning. Although it is classified as an agent with low to medium toxicity, severe poisoning can cause lethal outcome and death especially when there is a limited medical facility. We describe a case of severe Propanil poisoning who was successfully treated in a peripheral hospital with available facilities.