A critical review on sources and environmental behavior of organophosphorus flame retardants in the soil: Current knowledge and future perspectives.

Organophosphorus flame retardants (OPFRs) have been widely used in industrial and commercial applications. Unfortunately, the chemical constituents of OPFRs, organophosphate esters (OPEs), which have been proven to be carcinogenic and biotoxic, can release into the environment and pose potential risks to human health. This paper reviews the research progress of OPEs in the soil through bibliometric analysis and comprehensively elaborates on their pollution status, potential sources, and environmental behaviors. The OPE pollution is widely distributed in the soil at concentrations ranging from several to tens of thousands of ng/g dw. Some novel OPEs, newly discovered OPEs in the environment in recent years, are also detected. OPE concentrations vary substantially among landuses, and waste processing areas are important point sources of OPE pollution in the soil. Emission source intensity, physicochemical properties of compounds, and soil properties play important roles in the transfer process of OPEs in the soil. Biodegradation, especially microbial degradation, has potential application prospects in the remediation of OPE-contaminated soil. Brevibacillus brevis, Sphingomonas, Sphingopyxis, Rhodococcus, and other microorganisms can degrade some OPEs. This review helps clarify the pollution status of OPEs in the soil and highlights perspectives for future research.

Organophosphate esters in soils of Beijing urban parks: Occurrence, potential sources, and probabilistic health risks.

Organophosphate esters (OPEs) are an emerging contaminant widely distributed in the soil. OPEs have drawn increasing attention for their biological toxicity and possible threat to human health. This research investigated the pollution characteristics of two typical OPEs, organophosphate triesters (tri-OPEs) and organophosphate diesters (di-OPEs), in soils of 104 urban parks in Beijing. The median concentrations of Σ11tri-OPEs and Σ8di-OPEs were 157 and 17.9 ng/g dw, respectively. Tris(2-chloroisopropyl) phosphate and bis(2-ethylhexyl) phosphate were the dominant tri-OPE and di-OPE, respectively. Consumer materials (such as building insulation and decorative materials), traffic emissions, and reclaimed water irrigation may be critical sources of tri-OPEs in urban park soils. Di-OPEs mainly originated from the degradation of parent compounds and industrial applications. Machine learning models were employed to determine the influencing factors of OPEs and predict changes in their concentrations. The predicted OPEs concentrations in Beijing urban park soils in 2025 and 2030 are three times and five times those in 2018, respectively. According to probabilistic health risk assessment, non-carcinogenic and carcinogenic risks of OPEs can be negligible for children and adults. Our results could inform measures for preventing and controlling OPEs pollution in urban park soils.

[Clinical effects of autologous follicular unit extraction transplantation in the treatment of small area secondary cicatricial alopecia after burns].

Objective: To explore the clinical effects of autologous follicular unit extraction (FUE) transplantation in the treatment of small area secondary cicatricial alopecia (hereinafter referred to as cicatricial alopecia) after burns. Methods: A retrospective observational study was carried out. According to the adopted treatment methods, 18 patients (12 males and 6 females, aged (29±6) years) who received autologous FUE transplantation for small area cicatricial alopecia after burns from March 2017 to November 2019 in the First Affiliated Hospital of Air Force Medical University were included in FUE transplantation group, and 18 patients (13 males and 5 females, aged (33±5) years) who were treated with expanded flap transplantation for small area cicatricial alopecia after burns by the same surgery team during the same period in the same hospital were included in expanded flap transplantation group. All the patients were followed up for more than 1 year. At the last follow-up, the follicular unit density in the transplanted area was measured by Folliscope hair detection system and the hair survival rate was calculated; the visual analogue scale (VAS) method was adopted to evaluate the treatment effect; patients were asked their satisfaction with the treatment effect and the occurrence of complications during follow-up; the hair growth and the scalp thickness, pain, pruritus, pigmentation, and surface roughness of the transplanted area were recorded. Data were statistically analyzed with Fisher's exact probability test and independent sample t test. Results: At the last follow-up, the follicular unit density in the transplanted area of patients in FUE transplantation group was (46.8±2.0)/cm2, which was significantly higher than (42.5±4.3)/cm2 in expanded flap transplantation group (t=3.84, P<0.01); the hair survival rates of patients were similar between the two groups (P>0.05). At the last follow-up, VAS scores evaluating the treatment effect of patients were similar between the two groups (P>0.05); the satisfaction score of patients toward the treatment effect in FUE transplantation group was 8.6±1.1, which was significantly higher than 7.6±0.8 in expanded flap transplantation group (t=2.89, P<0.01). During the follow-up, no inflammation or infection occurred in patients of the two groups, but only 2 patients in expanded flap transplantation group had postoperative pain. At the last follow-up, the transplanted area of patients in the two groups was covered with new hair, and the hair growth direction was basically consistent with the surrounding normal hair; scalp thickness, pain, pruritus, pigmentation, and surface roughness of the transplanted area of patients were similar between the two groups (P>0.05). Conclusions: Autologous FUE transplantation has better long-term follicular unit density and patients' satisfaction than expanded flap transplantation in the treatment of small area cicatricial alopecia after burns, showing better postoperative effect and a good prospect of clinical application.