Arsenic and fluoride in groundwater triggering a high risk: Probabilistic results using Monte Carlo simulation and species sensitivity distribution.

The widespread presence of arsenic (As) and fluoride (F-) in groundwater poses substantial risks to human health on a global scale. These elements have been identified as the most prevalent geogenic contaminants in groundwater in northern Mexico. Consequently, this study aimed to evaluate the human health and ecological risks associated with the content of As and F- in the Meoqui-Delicias aquifer, which is in one of Mexico's most emblematic irrigation districts. Concentrations of As and F- were measured in 38 groundwater samples using ICP-MS and ion chromatography, respectively. Overall, these elements showed a similar trend across the aquifer, revealing a positive correlation between them and pH. The concentration of As and F- in the groundwater ranged from 5.3 µg/L to 303 µg/L and from 0.5 mg/L to 8.8 mg/L, respectively. Additionally, the levels of As and F- surpassed the established national standards for safe drinking water in 92% and 97% of samples, respectively. Given that groundwater is used for both agricultural purposes and human activities, this study also assessed the associated human health and ecological risks posed by these elements using Monte Carlo simulation and Species Sensitivity Distribution. The findings disclosed a significant noncarcinogenic health risk associated with exposure to As and F-, as well as an unacceptable carcinogenic health risk to As through water consumption for both adults and children. Furthermore, a high ecological risk to aquatic species was identified for F- and high to medium risks for As in the sampling sites. Therefore, the findings in this study provide valuable information for Mexican authorities and international organizations (e.g., WHO) about the adverse effects that any exposure without treatment to groundwater from this region represents for human health.

Real-world experience of vedolizumab use in Colombian patients with inflammatory bowel disease-EXVEDOCOL.

BACKGROUND: Real-world studies about the effectiveness and safety of vedolizumab (VDZ) in the treatment of inflammatory bowel disease (IBD) in Latin America are scarce. Our study describes the effectiveness and safety of VDZ in Colombian patients with IBD. METHODS: EXVEDOCOL (EXperience of VEDOlizumab in COLombia) was a retrospective, multicenter, observational study. Adults with IBD receiving a first dose of VDZ between July 2016 and October 2018 were included. The co-primary outcomes clinical response, and remission, were determined at week 14 and last visit during the maintenance phase (LVMP). The secondary outcomes, deep remission and loss of response were recorded at LVMP. RESULTS: Thirty-one patients (25 ulcerative colitis (UC), 6 Crohn's disease (CD)) were included. At week 14, clinical response was achieved by 87.1% (27/31) of the patients treated with VDZ, while loss of response was reported in 6.7% (2/30). The remission rate at week 14 was 65.5% (19/29) and 75.9% (22/29) at LVMP. Prior anti-TNF exposure was reported in 61.3% (19 patients) of whom 84.2% (16/19) achieved clinical response at week 14 and 89.5% (17/19) at LVMP. For anti-TNF naïve patients, clinical response was recorded in 91.7% (11/12) at week 14 and 100% (12/12) at LVMP. CONCLUSIONS: High clinical remission rates and safety profile highlight VDZ as a valuable treatment option for IBD patients. Anti-TNF naïve patients may derive greater benefit from therapy. Studies with larger cohorts could confirm these findings.

Factores de riesgo asociados a desórdenes musculoesqueléticos en miembros superiores en personal de salud / Risk factors associated with musculoskeletal disorders in upper extremities in health personnel

Introducción: los desórdenes osteomusculares en miembros superiores presentan los mayores índices entre las enfermedades laborales y los profesionales del sector salud no son la excepción. Un análisis minucioso de los factores de riesgo puede orientar una intervención pertinente. Objetivo: analizar factores de riesgo asociados a desórdenes musculoesqueléticos de miembros superiores y su relación con cargos de profesionales de la salud de entidad sanitaria. Materiales y métodos: Se aplicó cuestionario a 93 profesionales sobre aspectos demográficos, percepción de factores de riesgo intralaborales y actividades extralaborales asociadas con la generación de trastornos musculoesqueléticos en miembros superiores. Coeficientes de contingencia y V de Cramer determinaron intensidad de relación entre factores de riesgos y cargos. Resultados: Se encontró relación entre cargos de Enfermería, Fisioterapia, Bacteriología, Medicina y Odontología con factores como agarres, movimientos combinados con fuerza, posturas forzadas, movimientos repetitivos con posturas forzadas y el sedentarismo. Conclusiones: Se demostraron relaciones entre cargos asistenciales y factores de riesgo de la tarea que la literatura asocia con desordenes musculoesqueléticos en miembros superiores. También el sedentarismo de los profesionales presentó relaciones significativas. Es relevante considerar la promoción de la salud en los entornos de trabajo (AU)

Introduction: musculoskeletal disorders in the upper limbs have the highest rates among occupational diseases and health sector professionals are no exception. A thorough analysis of risk factors can guide an appropriate intervention. Objective: to analyze the risk factors associated with upper limb musculoskeletal disorders and their relationship with health personnel in an entity. Material and Method: A questionnaire was applied to 93 professionals of health entity that inquired about demographic aspects and perception of occupational risk factors, as well as non-occupational risk factors associated with the generation of musculoskeletal disorders in upper limbs. The “contingency coefficient” and “Cramer’s V” were applied to determine the level of intensity of the relationship between present risk factors and charges. Results: A relationship was found between the functions of Nursing, Physiotherapy, Bacteriology, Medicine and Dentistry with factors such as grips, movements combined with strength, forced postures, repetitive movements, repetitive movements and forced postures and sedentary lifestyle. Conclusions: relationships were evidenced between care charges of the health entity and risk factors specific to the task that, according to the literature, are associated with musculoskeletal disorders in the upper limbs. Also the sedentary lifestyle of the professionals presented significant relationships. It is relevant to consider the health promotion in the workplace (AU)

Sorption of Polyfluoroalkyl Surfactants on Surface Soils: Effect of Molecular Structures, Soil Properties, and Solution Chemistry.

Zwitterionic, cationic, and anionic per- and polyfluoroalkyl substances (PFASs) are identified in aqueous film-forming foam (AFFF) concentrates and AFFF-impacted sites. However, the mobility potential of zwitterionic and cationic PFASs is poorly understood, preventing reliable site assessment. The study aimed to elucidate the mobility behaviors of PFASs of various charge states in saturated soil-water systems and assess critical influencing factors. Five anionic, three zwitterionic, and one cationic PFASs were investigated in five soils through batch sorption experiments. Pairwise comparison revealed that the quaternary ammonium group imparted a strong affinity of cationic perfluorooctaneamide ammonium compound (PFOAAmS) for soils. The influence of the quaternary ammonium group is mitigated in polyfluoroalkyl betaines, yet perfluorooctane sulfonamidoalkyl betaine (PFOSB) showed strong sorption in selected soils. Two soil bulk properties showed some correlations with the soil-water distribution coefficient (Kd). A positive correlation with the fraction of soil organic carbon was found only for anionic PFASs, whereas cation exchange capacity had an approximate positive correlation with Kd only for PFOAAmS. Water chemistry (Ca2+ and pH) influences the sorption of nonanionic PFASs in very distinct fashions or even in opposite trends to what was known for anionic PFASs. Sorption was insensitive to pH changes except for PFOSB; PFOSB underwent profound sorption reduction because its speciation occurs around neutral pH, while the two other betaines and PFOAAmS have pKa values that are outside of the environmentally relevant range. The lack of correlations suggests that the transport potential of PFASs is probably highly site-specific. It remains a challenge in deciphering PFAS sorption mechanisms and predicting how AFFF plumes migrate.

Zwitterionic, cationic, and anionic perfluoroalkyl and polyfluoroalkyl substances integrated into total oxidizable precursor assay of contaminated groundwater.

The total oxidizable precursor (TOP) assay can be useful for integrating precursors to perfluoroalkyl acids (pre-PFAAs) into the assessment of sites contaminated by per- and polyfluoroalkyl substances (PFAS). Current research gaps include risks of instrumental matrix effects due to the complexity of post-oxidation extracts, potential reproducibility issues during TOP itself, and limited information for zwitterionic and cationic pre-PFAAs. We first investigated a suitable method for the analysis of groundwater samples, using liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). Initial sample pre-treatment through filtration could affect the dissolved PFAS concentrations and was therefore avoided. Amending the postoxidation samples with methanol allowed for improved precision and low instrumental matrix effects. We also documented the oxidation yields of 23 anionic, neutral, zwitterionic, and cationic precursor compounds of PFAAs. These precursor compounds were amenable to TOP conversion. The total oxidative yield of 6:2 fluorotelomer sulfonamidoalkyl betaine (6:2 FTAB), for instance, was 80 mol%, with C3-C5 PFCAs as major oxidation products (minor: C6-C7 PFCAs). The method was applied to determine a wide range of PFAS (n = 41) without oxidation as well as ΔPFCA via persulfate oxidation in AFFF-impacted groundwater samples from fire-equipment testing sites in Ontario and Newfoundland, Canada. Summed PFAS concentrations as high as 5 mg L-1 were reported before oxidation, and post-oxidation increases of PFCAs up to + 2300% were observed. A significant contribution of increases in individual PFCAs was attributed to precursors such as 6:2 FTAB, fluorotelomer sulfonates (6:2 FtS, 8:2 FtS), perfluorooctane sulfonamidoalkyl amine (PFOSAm), and perfluorohexane sulfonamide (FHxSA) at the active firefighting training site.

Isomer-specific biotransformation of perfluoroalkyl sulfonamide compounds in aerobic soil.

As an important reservoir of pollutants, soil may play a critical role in altering isomer ratios of perfluorooctane sulfonate (PFOS) or PFOS precursors (PrePFOS) via microbial processes, but this possibility has not yet been investigated, as well as the feasibility of using PFOS isomer ratio for source tracking in PFOS contaminated sites. In the present study, N­ethyl perfluorooctane sulfonamide ethanol (EtFOSE) of the technical grade was incubated in soil microcosms for 105 days to examine isomer-specific transformation processes. Experimental data combined with a mathematical model suggest new biotransformation pathways leading to PFOS, including a direct pathway to produce PFOS via hydrolysis of the sulfonamide bond. A similar rate of biotransformation was observed for EtFOSE with an estimated half-life of 8.7 and 9.6 days for the branched and linear isomers, respectively, without statistical difference. Two transformation intermediates, N­ethyl perfluorooctanoic acid (EtFOSAA) and perfluorooctane sulfonamide (FOSA), also showed preferential biotransformation of branched isomers. On the contrary, one intermediate N­ethyl perfluorooctane sulfonamide (EtFOSA) showed the preferred transformation of the linear isomer with an estimated half-life of 80.8 and 11.2 days for the branched and linear isomers, respectively. As PFOS is likely to be generated through more than one pathway or one precursor, its final isomer ratio is collectively determined by several upstream reactions, each having specific isomer-specific transformation kinetics. Though the soil showed enrichment of branched PFOS isomers during the 4-month incubation, compared to PFOS standards, some uncertainty arises in concluding preferential generation of branched PFOS from its precursors, due to the lack of standards for branched PreFOS. The complexity of isomer-specific biotransformation only reinforced the challenge of applying the PFOS isomer ratio for source tracking in environmental microbial systems.

Caracterización funcional y calidad de vida en pacientes con enfermedad de Parkinson en un hospital de tercer nivel de Bogotá D. C., Colombia / Functional characterization and quality of life in patients with Parkinson's disease in a third level hospital Bogotá D. C., Colombia

Introducción. La enfermedad de Parkinson es considerada la segunda enfermedad neurodegenerativa que más genera discapacidad motora y neuropsiquiátrica; es un trastorno de causa multifactorial cuyo síntoma cardinal es la bradicinesia, seguida de temblor, rigidez e inestabilidad postural, síntomas que impactan la funcionalidad y la calidad de vida del pacien- te. Estudios epidemiológicos muestran que la prevalencia del Parkinson en Colombia es de 4,7 afectados por cada 1.000 personas mayores de 50 años, por lo que es necesario cuantificar el compromiso y las necesidades de atención de estos pacientes. Objetivos. Hacer una caracterización funcional y de la calidad de vida de 60 pacientes con enfermedad de Parkinson atendidos en un hospital de tercer nivel de Bogotá D.C., Colombia, entre noviembre de 2015 y junio de 2016. Materiales y métodos. Estudio de corte transversal con componente analítico realizado en 60 pacientes que cumplieron los criterios de inclusión. Se aplicó el cuestionario de calidad de vida PDQ-39 y la escala de funcionalidad para pacientes con enfermedad de Parkinson MDS- UPDRS. Resultados. El promedio de edad de la muestra fue 67 años, con un rango entre 40 y 84 años, y el 55% eran hombres. El mayor deterioro se evidenció en los dominios de movilidad, activi- dades de la vida diaria, cognición y molestias corporales. Conclusiones. La muestra examinada evidenció un compromiso moderado en la calidad de vida, en los dominios de movilidad y las actividades de la vida diaria. En el aspecto funcional, clínicamente se encontró un compromiso motor en los aspectos de bradicinesia, marcha y rigidez.

Introduction. Parkinson's disease is considered the second neurodegenerative disease that most generates motor and neuropsychiatric disability; it is a multifactorial disorder whose cardinal symptom is bradykinesia, followed by tremor, rigidity and postural instability, symptoms that impact the functionality and quality of life of the patient. Epidemiological studies show that the prevalence of Parkinson's disease in Colombia is 4.7 affected per 1,000 people over 50 years of age, so it is necessary to quantify the commitment and care needs of these patients. Objectives. To make a functional and quality of life characterization of 60 patients with Parkinson's disease attended in a third level hospital in Bogotá D.C., Colombia, between November 2015 and June 2016. Materials and methods. Cross-sectional study with analytical component conducted in 60 patients who met the inclusion criteria. The PDQ-39 quality of life questionnaire and the functionality scale for patients with Parkinson's disease MDS- UPDRS were applied. Results. The average age of the sample was 67 years, with a range between 40 and 84 years, and 55% were men. The greatest impairment was evidenced in the domains of mobility, activities of daily living, cognition and body discomfort. Conclusions. The sample examined showed moderate compromise in quality of life, in the mobility domains and activities of daily living. In the functional aspect, clinically, motor compromise was found in the aspects of bradykinesia, gait and rigidity.

Ejercicio en prevención primaria de enfermedad cardiovascular y cáncer / Exercise in primary prevention of cardiovascular disease and cancer / Exercício em prevenção primária de doença cardiovascular e câncer

Resumen La enfermedad cardiovascular es un trastorno que se desarrolla de manera progresiva a lo largo del proceso vital, y que con la aparición de los síntomas ya está instaurada incluso en estadios avanzados, asociada a discapacidad y pérdida de funcionalidad. La enfermedad cardiovascular está directamente relacionada con diferentes factores de riesgo modificables, como tabaquismo, dieta elevada en grasas saturadas, estrés, obesidad, diabetes mellitus y sedentarismo. Dedicaremos especial interés a la importancia del ejercicio y de la actividad física en la prevención primaria de la enfermedad cardiovascular y de sus beneficios. De igual manera, el ejercicio tiene importantes beneficios en la prevención del cáncer como enfermedad crónica, que se describirán en este artículo.

Abstract Cardiovascular disease is a disorder that develops progressively throughout life, and when symptoms appear the disease is already deeply established and in some cases already in advanced stages, associated with disability and loss of functionality. Cardiovascular disease is directly related to different modifiable risk factors, such as smoking, diets high in saturated fat, stress, obesity, diabetes mellitus and sedentary lifestyle. We will devote special interest to the importance of exercise and physical activity in the primary prevention of cardiovascular disease and its benefits. Similarly, exercise has important benefits in preventing cancer as a chronic disease, which will also be described in this article.

Resumo A doença cardiovascular é um transtorno que se desenvolve de maneira progressiva ao longo do processo vital, e que com o aparecimento dos sintomas já está instaurada inclusive em estágios avançados, associada à deficiência e à perda de funcionalidade. A doença cardiovascular está diretamente relacionada com diferentes fatores de risco modificáveis, como tabaquismo, dieta elevada em gorduras saturadas, estresse, obesidade, diabetes mellitus e sedentarismo. Dedicaremos especial interesse à importância do exercício e da atividade física na prevenção primária da doença cardiovascular e de seus benefícios. Do mesmo modo, o exercício tem importantes benefícios na prevenção do câncer como doença crónica que são descritos neste artigo.

Optimization of extraction methods for comprehensive profiling of perfluoroalkyl and polyfluoroalkyl substances in firefighting foam impacted soils.

The comprehensive analysis of aqueous film forming foam (AFFF) formulations has led in recent years to the discovery of novel classes of perfluoroalkyl and polyfluoroalkyl substances (PFASs). Whether the pre-existing analytical methods for historically monitored PFASs, including perfluorooctane sulfonate (PFOS), could be transferable to a large breadth of newly identified PFASs remains, however, an open question. Data from various lines of evidence indicate that current extraction procedures previously validated with anionic and neutral PFASs may seriously underperform for many cationic and zwitterionic PFASs. The extraction efficiency and instrumental response could be strongly matrix-dependent, which may preclude a robust analysis. The present study sought to investigate a suitable sample preparation procedure for the analysis of anionic, cationic, and zwitterionic PFASs in soil samples. In total, 86 PFASs, representing 24 chemical classes previously discovered in AFFF formulations or at AFFF-impacted sites, were evaluated. The merits and limitations of various extraction media were examined using an AFFF-impacted field-weathered loam soil, as well as a background loam soil amended with AFFFs in-house. Methanol with hydrochloric acid provided excellent recoveries for most cationic and zwitterionic PFASs, including fluorotelomer sulfonamidoalkyl betaines (e.g., 6:2 FTAB) and fluorotelomer betaines (e.g., 9:1:2 FTB), yet performed less satisfactorily for certain anionic PFASs, and may also cause conversion of some PFASs. Sequential extractions using methanol with ammonium acetate exhibited limited matrix effects and suitable recoveries of PFASs from soils of diverse textural classes and organic matter content. The newly-developed extraction method presented the best option for future in-depth characterization of PFASs at AFFF-impacted sites.

Novel Fluoroalkylated Surfactants in Soils Following Firefighting Foam Deployment During the Lac-Mégantic Railway Accident.

The derailment of an unmanned train carrying crude oil and subsequent fire in the town of Lac-Mégantic, Quebec, led to the use of 33 000 L of aqueous film forming foam (AFFF) concentrate. While it is known that per- and polyfluoroalkyl substances (PFASs) contained in AFFFs pose a potential environmental and health risk, critical knowledge gaps remain as regards to their environmental fate after release. The accident in Lac-Mégantic provided valuable information regarding the identity and concentration of PFASs present in the soil after the AFFF deployment, as well as their possible transformation over time. The current study analyzed four sets of samples from Lac-Mégantic: soil collected days after the accident from a heavily impacted area, soil sampled two years later from the treatment biopiles, soil collected two years after the accident from downtown Lac-Mégantic, and nonimpacted soil from a nearby area. A total of 33 PFASs were quantified in the soils. The highest observed concentrations correspond to those of 6:2 fluorotelomer sulfonamidoalkyl betaine, 6:2 and 8:2 fluorotelomer sulfonates, and short chain perfluorocarboxylic acids. The soils collected in Lac-Mégantic two years after the accident show a total PFAS concentration that is ∼50 times lower than soils collected in 2013, while the proportion of perfluoroalkyl acids in those samples shows an increase. Qualitative analysis revealed the presence in soil of 55 additional PFASs that had been previously identified in AFFF formulations. The present study highlights the need to perform detailed analysis of AFFF impacted sites, instead of focusing solely on perfluoroalkyl acids.

Assessment of the Influence of Soil Characteristics and Hydrocarbon Fuel Cocontamination on the Solvent Extraction of Perfluoroalkyl and Polyfluoroalkyl Substances.

Sites impacted by the use of aqueous film-forming foams (AFFFs) present elevated concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFAS). The characterization of the PFAS contamination at such sites may be greatly complicated by the presence of hydrocarbon cocontaminants and by the large variety of PFAS potentially present in AFFFs. In order to further a more comprehensive characterization of AFFF-contaminated soils, the solvent extraction of PFAS from soil was studied under different conditions. Specifically, the impact of soil properties (textural class, organic matter content) and the presence of hydrocarbon contamination (supplemented in the form of either diesel or crude oil) on PFAS recovery performance was evaluated for two extraction methods [methanol/sodium hydroxide (MeOH/NaOH) and methanol/ammonium hydroxide (MeOH/NH4OH)]. While both methods performed satisfactorily for perfluoroalkyl acids and fluorotelomer sulfonates, the extraction of newly identified surfactants with functionalities such as betaine and quaternary ammonium was improved with the MeOH/NaOH based method. The main factors that were found to influence the extraction efficiency were the soil properties; a high organic matter or clay content was observed to negatively affect the recovery of the newly identified compounds. While the MeOH/NaOH solvent yielded more efficient recovery rates overall, it also entailed the disadvantage of presenting higher detection limits and substantial matrix effects at the instrumental analysis stage, requiring matrix-matched calibration curves. The results discussed herein bear important implications for a more comprehensive and reliable environmental monitoring of PFAS components at AFFF-impacted sites.

Generation of Perfluoroalkyl Acids from Aerobic Biotransformation of Quaternary Ammonium Polyfluoroalkyl Surfactants.

The aerobic biotransformation over 180 days of two cationic quaternary ammonium compounds (QACs) with perfluoroalkyl chains was determined in soil microcosms, and biotransformation pathways were proposed. This is the first time that polyfluoroalkyl cationic surfactants used in aqueous film-forming foam (AFFF) formulations were studied for their environmental fate. The biotransformation of perfluorooctaneamido quaternary ammonium salt (PFOAAmS) was characterized by a DT50 value (time necessary to consume half of the initial mass) of 142 days and significant generation of perfluoroalkyl carboxylic acid (PFOA) at a yield of 30 mol % by day 180. The biotransformation of perfluorooctane sulfonamide quaternary ammonium salt (PFOSAmS) was very slow with unobservable change of the spiked mass; yet the generation of perfluorooctanesulfonate (PFOS) at a yield of 0.3 mol % confirmed the biotransformation of PFOSAmS. Three novel biotransformation intermediates were identified for PFOAAmS and three products including perfluorooctane sulfonamide (FOSA) for PFOSAmS through high-resolution mass spectrometry (MS) analysis and t-MS(2) fragmentation. The significantly slower PFOSAmS biotransformation is hypothesized to be due to its stronger sorption to soil owing to a longer perfluoroalkyl chain and a bulkier sulfonyl group, when compared to PFOAAmS. This study has demonstrated that despite overall high stability of QACs and their biocide nature, the ones with perfluoroalkyl chains can be substantially biotransformed into perfluoroalkyl acids in aerobic soil.

Production of PFOS from aerobic soil biotransformation of two perfluoroalkyl sulfonamide derivatives.

The continuous production and use in certain parts of the world of perfluoroalkyl sulfonamide derivatives that can degrade to perfluorooctane sulfonic acid (PFOS) has called for better understanding of the environmental fate of these PFOS precursors. Aerobic soil biotransformation of N-ethyl perfluorooctane sulfonamide (EtFOSA, also known as Sulfluramid) was quantitatively investigated in semi-closed soil microcosms over 182 d for the first time. The apparent soil half-life of EtFOSA was 13.9±2.1 d and the yield to PFOS by the end of incubation was 4.0 mol%. A positive identification of a previously suspected degradation product, EtFOSA alcohol, provided strong evidence to determine degradation pathways. The lower mass balance in sterile soil than live soil suggested likely strong irreversible sorption of EtFOSA to the test soil. The aerobic soil biotransformation of a technical grade N-ethyl perfluorooctane sulfonamidoethanol (EtFOSE) was semi-quantitatively examined, and the degradation pathways largely followed those in activated sludge and marine sediments. Aside from PFOS, major degradation products included N-Ethyl perfluorooctane sulfonamidoacetic acid (EtFOSAA), perfluorooctane sulfonamide (FOSA) and perfluorooctane sulfonamide acetic acid (FOSAA). This study confirms that aerobic soil biotransformation of EtFOSE and EtFOSA contributes significantly to the PFOS observed in soil environment, as well as to several highly persistent sulfonamide derivatives frequently detected in biosolid-amended soils and landfill leachates.

Microbial degradation of polyfluoroalkyl chemicals in the environment: a review.

Polyfluoroalkyl chemicals containing perfluoroalkyl moieties have been widely used in numerous industrial and commercial applications. Many polyfluoroalkyl chemicals are potential perfluoroalkyl acid (PFAA) precursors. When they are released to the environment, abiotic and microbial degradation of non-fluorinated functionalities, polyfluoroalkyl and perfluoroalkyl moieties can result in perfluoroalkyl carboxylic (PFCAs) and sulfonic acids (PFSAs), such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). These highly persistent and ubiquitously detected PFAAs are the subjects of many regulations and actions due to their toxic profiles. In order to confidently evaluate the environmental fate and effects of these precursors and their links to PFSAs and PFCAs, we present the review into the environmental biodegradability studies carried out with microbial culture, activated sludge, soil and sediment in the past decade. First, we propose that the knowledge gap caused by the lack of direct detection of precursor chemicals in environmental samples can be bridged by laboratory investigations of important precursors such as fluorotelomer-based compounds and perfluoroalkane sulfonamido derivatives. Then we evaluate the experimental setups and methodologies, sampling and sample preparation methods, and analytical techniques that have been successfully applied. Third, we provide the most updated knowledge on quantitative and qualitative relationships between precursors and PFSAs or PFCAs, microbial degradation pathways, half-lives of precursors, defluorination potential, and novel degradation intermediates and products. In the end, we identify knowledge gaps and suggest research directions with regard to future biodegradation studies, environmental monitoring and ecotoxicological assessment of perfluoroalkyl and polyfluoroalkyl chemicals.