Microbial remediation of a pentachloronitrobenzene-contaminated soil under Panax notoginseng: A field experiment

Abstract

Pentachloronitrobenzene (PCNB) is an organochlorine fungicide that is mainly used in the prevention and control of diseases in crop seedlings. Microbial removal is used as a promising method for in-situ removal of many organic pesticides and pesticide residues. A short-term field experiment (1 year) was conducted to explore the potential role of a PCNB-degrading bacterial isolate, Cupriavidus sp. YNS-85, in the remediation of a PCNB-contaminated soil on which Panax notoginseng was grown. The following three treatments were used: i) control soil amended with wheat bran but without YNS-85, ii) soil with 0.15 kg m −2 of solid bacterial inoculum (A), and iii) soil with 0.30 kg m −2 of solid bacterial inoculum (B). The removal of soil PCNB during the microbial remediation was monitored using gas chromatography. Soil catalase and fluorescein diacetate (FDA) esterase activities were determined using spectrophotometry. In addition, cultivable bacteria, fungi, and actinomycetes were counted by plating serial dilutions, and the microbial biodiversity of the soil was analyzed using BIOLOG. After 1 year of in-situ remediation, the soil PCNB concentrations decreased significantly by 50.3% and 74.2% in treatments A and B, respectively, when compared with the uninoculated control. The soil catalase activity decreased in the presence of the bacterial isolate, the FDA esterase activity decreased in treatment A, but increased in treatment B. No significant changes in plant biomass, diversity of the soil microbial community, or physicochemical properties of the soil were observed between the control and inoculated groups (P < 0.05). The results indicate that Cupriavidus sp. YNS-85 is a potential candidate for the remediation of PCNB-contaminated soils under P. notoginseng.

Biological Reduction of Organic Matter in Buji River Sediment (Shenzhen, China) with Artificial Oxygenation

“…The plate count method was employed to determine the total bacteria count of the sediment samples [29]. First, 10.0 g of sample were put into 90 mL of sterile water in an ultra-clean bench.…”

PCNB exposure during early embryogenic development induces developmental delay and teratogenicity by altering the gene expression in Xenopus laevis

“…Due to its stability and solubility, it is relatively persistent in environment and has the potential to be transported from the terrestrial to the aquatic environment 3 . It is reported that PCNB has exhibited 96 h lethal concentration of 50% (LC 50 ) 0.55 mg/L and 0.1 mg/L respectively for rainbow trout and bluegill sunfish while for opossum (shrimp) 48 h LC 50 values are reported as 18 μg/L 4,5 . PCNB has been classified as a Toxicity Class III chemical by the United States Environmental Protection Agency (USEPA) due to its adverse environmental effects and health concerns 6…”

“…3 It is reported that PCNB has exhibited 96 h lethal concentration of 50% (LC 50 ) 0.55 mg/L and 0.1 mg/L respectively for rainbow trout and bluegill sunfish while for opossum (shrimp) 48 h LC 50 values are reported as 18 μg/L. 4,5 PCNB has been classified as a Toxicity Class III chemical by the United States Environmental Protection Agency (USEPA) due to its adverse environmental effects and health concerns. 6 PCNB is used to treat seeds and turf grass in a number of countries, including China, Canada, and the USA.…”