Carbamazepine and diclofenac: removal in wastewater treatment plants and occurrence in water bodies

In the aquatic environment, pharmaceuticals have been widely found. Among them, carbamazepine and diclofenac were detected at the highest frequency. To evaluate the worldwide environmental impacts of both drugs, their global consumption volumes are estimated, based on the dose per capita. The metabolites of these pharmaceuticals are also of environmental concerns, especially trans-10,11-dihydro-10,11- dihydroxycarbamazepine (CBZ-diol) which probably has a similar concentration in water bodies to that of its parent drug. The removal efficiencies and mechanisms of both drugs in the wastewater treatment plants (WWTPs) are discussed with the actual state of knowledge. The occurrences of both drugs are examined in various water bodies including WWTP effluents, surface waters, groundwater and drinking water. Their chemical, physical and pharmacological properties are also addressed in context, which can largely influence their environmental behaviors. The ecotoxicological studies of both drugs imply that they do not easily cause acute toxic effects at their environmental concentrations. However their chronic effects need cautious attention.     

Antimicrobial potential of the ionophore monensin on freshwater biofilm bacteria

Microorganisms play key roles in stream ecosystems, but comparatively little is known about the resilience of freshwater bacterial communities and their susceptibility to the chemical by-products of agricultural land use. Antibiotics used in the agricultural sector are of particular concern and have been detected in waterways associated with agricultural land. Despite widespread agricultural intensification globally and the sector's high antibiotic use, the effects of agricultural antibiotic by-products on stream microbial communities have yet to be characterised. We investigated the impacts of the antibiotic monensin on microbial biofilm communities in a simulated contamination event using streamside-replicated channels. A 24-h pulse experiment in flow channels precolonised by stream biofilm microbial communities contrasted the effects of monensin concentrations ranging from realistic to extreme toxicity levels (1–550 ug L^?1). Biofilm community composition was characterised immediately before and after the pulse for several weeks using automated ribosomal intergenic spacer analysis. Despite applying acutely toxic levels of monensin, only limited effects to biofilm community composition were detected immediately after antibiotic application, and these disappeared within 4 days. Rather, temporal factors drove biofilm differences, highlighting the overriding importance of wider, catchment-level, physiochemical hydrological influences on structuring freshwater biofilm communities, as opposed to localised and sporadic agricultural surface runoff contamination events containing antibiotics.     

Fate of selected pharmaceuticals in hospital and municipal wastewater effluent: occurrence,removal, and environmental risk assessment

The concentrations and distribution of β-blockers, lipid regulators, and psychiatric and cancer drugs in the influent and effluent of the municipal wastewater treatment plant (WWTP) and the effluent of 16 hospitals that discharge into the wastewater treatment plant mentioned in this study at two sampling dates in summer and winter were examined. The pharmaceutical contribution of hospitals to municipal wastewater was determined. The removal of target pharmaceuticals was evaluated in a WWTP consisting of conventional biological treatment using activated sludge. Additionally, the potential environmental risk for the aquatic receiving environments (salt lake) was assessed. Beta-blockers and psychiatric drugs were detected in high concentrations in the wastewater samples. Atenolol (919 ng/L) from β-blockers and carbamazepine (7008 ng/L) from psychiatric pharmaceuticals were detected at the highest concentrations in hospital wastewater. The total pharmaceutical concentration determined at the WWTP influent and effluent was between 335 and 737 ng/L in summer and between 174 and 226 ng/L in winter. The concentrations detected in hospital effluents are higher than the concentrations detected in WWTP. The total pharmaceutical contributions from hospitals to the WWTP in summer and winter were determined to be 2% and 4%, respectively. Total pharmaceutical removal in the WWTP ranged from 23 to 54%. According to the risk ratios, atenolol could pose a high risk (risk quotient > 10) for fish in summer and winter. There are different reasons for the increase in pharmaceutical consumption in recent years. One of these reasons is the COVID-19 pandemic, which has been going on for 2 years. In particular, hospitals were operated at full capacity during the pandemic, and the occurrence and concentration of pharmaceuticals used for the therapy of COVID-19 patients has increased in hospital effluent. Pandemic conditions have increased the tendency of people to use psychiatric drugs. It is thought that beta-blocker consumption has increased due to cardiovascular diseases caused by COVID-19. Therefore, the environmental risk of pharmaceuticals for aquatic organisms in hospital effluent should be monitored and evaluated.

     

Pharmaceuticals and personal care products found in the Great Lakes above concentrations of environmental concern

The monitoring of pharmaceuticals and personal care products (PPCPs) has focused on the distribution in rivers and small lakes, but data regarding their occurrence and effects in large lake systems, such as the Great Lakes, are sparse. Wastewater treatment processes have not been optimized to remove influent PPCPs and are a major source of PPCPs in the environment. Furthermore, PPCPs are not currently regulated in wastewater effluent. In this experiment we evaluated the concentration, and corresponding risk, of PPCPs from a wastewater effluent source at varying distances in Lake Michigan. Fifty-four PPCPs and hormones were assessed on six different dates over a two-year period from surface water and sediment samples up to 3.2 km from a wastewater treatment plant and at two sites within a harbor. Thirty-two PPCPs were detected in Lake Michigan and 30 were detected in the sediment, with numerous PPCPs being detected up to 3.2 km away from the shoreline. The most frequently detected PPCPs in Lake Michigan were metformin, caffeine, sulfamethoxazole, and triclosan. To determine the ecological risk, the maximum measured environmental concentrations were compared to the predicted no-effect concentration and 14 PPCPs were found to be of medium or high ecological risk. The environmental risk of PPCPs in large lake systems, such as the Great Lakes, has been questioned due to high dilution; however, the concentrations found in this study, and their corresponding risk quotient, indicate a significant threat by PPCPs to the health of the Great Lakes, particularly near shore organisms.     

Pharmaceutical contamination in residential, industrial, and agricultural waste streams: risk to aqueous environments in Taiwan

This is a comprehensive study of the occurrence of antibiotics, hormones and other pharmaceuticals in water sites that have major potential for downstream environmental contamination. These include residential (hospitals, sewage treatment plants, and regional discharges), industrial (pharmaceutical production facilities), and agricultural (animal husbandries and aquacultures) waste streams. We assayed 23 Taiwanese water sites for 97 targeted compounds, of which a significant number were detected and quantified. The most frequently detected compounds were sulfamethoxazole, caffeine, acetaminophen, and ibuprofen, followed closely by cephalexin, ofloxacin, and diclofenac, which were detected in >91% of samples and found to have median (maximum) concentrations of 0.2 (5.8), 0.39 (24.0), 0.02 (100.4), 0.41 (14.5), 0.15 (31.4), 0.14 (13.6) and 0.083 (29.8) microg/L, respectively. Lincomycin and acetaminophen had high measured concentrations (>100 microg/L), and 35 other pharmaceuticals occurred at the microg/L level. These incidence and concentration results correlate well with published data for other worldwide locations, as well as with Taiwanese medication usage data, suggesting a human contamination source. Many pharmaceuticals also occurred at levels exceeding predicted no-effect concentrations (PNEC), warranting further investigation of their occurrence and fate in receiving waters, as well as the overall risks they pose for local ecosystems and human residents. The information provided here will also be useful for development of strategies for regulation and remediation.     

The occurrence of illicit and therapeutic pharmaceuticals in wastewater effluent and surface waters in Nebraska

The occurrence and estimated concentration of twenty illicit and therapeutic pharmaceuticals and metabolites in surface waters influenced by wastewater treatment plant (WWTP) discharge and in wastewater effluents in Nebraska were determined using Polar Organic Chemical Integrative Samplers (POCIS). Samplers were installed in rivers upstream and downstream of treated WWTP discharge at four sites and in a discharge canal at a fifth location. Based on differences in estimated concentrations determined from pharmaceuticals recovered from POCIS, WWTP effluent was found to be a significant source of pharmaceutical loading to the receiving waters. Effluents from WWTPs with trickling filters or trickling filters in parallel with activated sludge resulted in the highest observed in-stream pharmaceutical concentrations. Azithromycin, caffeine, 1,7-dimethylzanthine, carbamazepine, cotinine, DEET, diphenhydramine, and sulfamethazine were detected at all locations. Methamphetamine, an illicit pharmaceutical, was detected at all but one of the sampling locations, representing only the second report of methamphetamine detected in WWTP effluent and in streams impacted by WWTP effluent.     

Spatial and temporal analysis of pharmaceutical concentrations in the upper Tennessee River basin

The behavior of pharmaceutical compounds in aquatic ecosystems is not well defined. In order to determine spatial and temporal variations in concentrations of pharmaceuticals in the Tennessee River, water samples were collected from multiple points along the river and at the inflow of major tributaries. Sampling structure was designed to investigate trends between surface and subsurface samples, seasonal trends (winter, spring, summer, and fall), the direct influence of sewage treatment plants (upstream versus downstream), and the effect of downstream distance on pharmaceutical concentrations. All samples were quantified via solid phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method yielded reproducible quantitation at low parts per trillion (ng L(-1)) levels for all 14 analytes (acetaminophen, atorvastatin, caffeine, carbamazepine, ciprofloxacin, diltiazem, fluoxetine, levofloxacin, lovastatin, norfluoxetine, ranitidine, sertraline, sulfamethoxazole, and trimethoprim). Correlation analyses (depth, distance) and repeated-measures ANOVAs (season, sewage treatment plant proximity) were used to determine statistically significant trends for frequently detected pharmaceuticals (caffeine, carbamazepine, sulfamethoxazole). Caffeine and sulfamethoxazole were found to vary by season in subsurface samples; spring exhibited the highest concentrations. Carbamazepine varied in proximity to sewage treatment plant outfall with subsurface samples yielding greater concentrations downstream than upstream. In addition, individual pharmaceuticals displayed positive correlation between surface and subsurface samples and negative correlation with downstream distance from the headwaters.     

Can aquatic distribution of human pharmaceuticals be related to pharmacological data?

The recognition of pharmaceuticals as significant environmental contaminants has only been a recent phenomenon. Therefore there is a paucity of data relating to the fate and effects of pharmaceuticals once they enter an aquatic receiving system. The amount of work that needs to be done in terms of risk assessment for pharmaceuticals required by regulatory agencies is substantial. This paper has determined the environmental partitioning coefficient (K_d) of 13 diverse human pharmaceuticals in three model systems of differing combinations of solid phases and solutions. The K_d values were then compared with distribution values of the pharmaceuticals in the human body determined from pharmacological studies. This was done to assess the functional relationship between K_d and distribution values in the human body (V_D). K_d values ranged from 3 to 2450 L kg⁻¹. Regression coefficients ranged from r² = 0.62–0.72, indicating that V_D values are a useful indicator for the K_d values of the tested pharmaceuticals within the batch sorption systems. The relationship between K_d and V_D should therefore be further explored to determine whether this relationship can be applied to a broader range of pharmaceuticals in more diverse environmental systems. Exploiting available human pharmacological data in such a way would be of great benefit in prioritising human pharmaceuticals as environmental contaminants in the risk assessment process.     

Fate of pharmaceuticals--photodegradation by simulated solar UV-light

The fate of pharmaceuticals in surface waters under solar irradiation was investigated. Photodegradation of pharmaceuticals caused by sun irradiation may be of major significance in the natural elimination process. Based on a data compilation from the literature, the lipid lowering agent metabolite clofibric acid, the iodinated X-ray contrast media iomeprol, which contribute to the adsorbable organic halogen compounds, and the antiepileptic drug carbamazepine were selected. The irradiation experiments were carried out in batch experiments with simulated UV–sunlight. The photodegradation of the pharmaceuticals showed a pseudo-first-order kinetics. The objective of this investigation was to demonstrate that the extent of photoinduced degradation of pharmaceuticals can vary significantly for the different pharmaceuticals and it strongly depends on the water constituents present in solution. The influences of different initial pharmaceutical concentrations, the presence of other pharmaceuticals like carbamazepine or clofibric acid and the presence of natural organic matter on the photochemical degradation rate of pharmaceuticals in aqueous solutions were investigated. Analyses of the pharmaceuticals and their photodegradation products were carried out by high performance liquid chromatography with diode-array and fluorescence detection.     

Phytotoxicity of 15 common pharmaceuticals on the germination of Lactuca sativa and photosynthesis of Chlamydomonas reinhardtii

Pharmaceuticals reach terrestrial environments through the application of treated wastewaters and biosolids to agricultural soils. We have investigated the toxicity of 15 common pharmaceuticals, classified as nonsteroidal anti-inflammatory drugs (NSAIDs), blood lipid-lowering agents, β-blockers and antibiotics, in two photosynthetic organisms. Twelve pharmaceuticals caused inhibitory effects on the radicle and hypocotyl elongation of Lactuca sativa seeds. The EC₅₀ values obtained were in the range of 170–5656 mg L⁻¹ in the case of the radicle and 188–4558 mg L⁻¹ for the hypocotyl. Propranolol was the most toxic drug for both root and hypocotyl elongation, followed by the NSAIDs, then gemfibrozil and tetracycline. Other effects, such as root necrosis, inhibition of root growth and curly hairs, were detected. However, even at the highest concentrations tested (3000 mg L⁻¹), seed germination was not affected. NSAIDs decreased the photosynthetic yield of Chlamydomonas reinhardtii, but only salicylic acid showed EC₅₀ values below 1000 mg L⁻¹. The first effects detected at low concentrations, together with the concentrations found in environmental samples, indicate that the use of biosolids and wastewaters containing pharmaceuticals should be regulated and their compositions assessed in order to prevent medium- and long-term impacts on agricultural soils and crops.

     

Occurrence of steroid hormones and antibiotics in shallow groundwater impacted by livestock waste control facilities

Wastewater impoundments at concentrated animal feeding operations (CAFOs) represent a potential source of veterinary pharmaceuticals and steroid hormone contamination to shallow groundwater. This study investigates the occurrence of seventeen veterinary pharmaceuticals and thirteen steroid hormones and hormone metabolites in lagoons and adjacent groundwater at operating swine and beef cattle facilities. These sites were chosen because subsurface geology and previous monitoring of nitrate, ammonia and chloride levels in shallow ground water strongly indicated direct infiltration, and as such represent worst cases for ground water contamination by waste water. Pharmaceutical compounds detected in samples obtained from cattle facilities include sulfamerazine; sulfamethazine; erythromycin; monensin; tiamulin; and sulfathiazole. Lincomycin; ractopamine; sulfamethazine; sulfathiazole; erythromycin; tiamulin and sulfadimethoxine were detected in wastewater samples obtained from swine facilities. Steroid hormones were detected less frequently than veterinary pharmaceuticals in this study. Estrone, testosterone, 4-androstenedione, and androsterone were detected in wastewater impoundments at concentrations ranging from 30 to 3600ng/L, while only estrone and testosterone were detected in groundwater samples at concentrations up to 390ng/L. The co-occurrence of veterinary pharmaceutical and steroid hormone contamination in groundwater at these locations and the correlation between pharmaceutical occurrence in lagoon wastewater and hydraulically downgradient groundwater indicates that groundwater underlying some livestock wastewater impoundments is susceptible to contamination by veterinary pharmaceuticals and steroid hormones originating in wastewater lagoons.     

Colloids as a sink for certain pharmaceuticals in the aquatic environment

Background, aim, and scope  

The occurrence and fate of pharmaceuticals in the aquatic environment is recognized as one of the emerging issues in environmental chemistry and as a matter of public concern. Existing data tend to focus on the concentrations of pharmaceuticals in the aqueous phase, with limited studies on their concentrations in particulate phase such as sediments. Furthermore, current water quality monitoring does not differentiate between soluble and colloidal phases in water samples, hindering our understanding of the bioavailability and bioaccumulation of pharmaceuticals in aquatic organisms. In this study, an investigation was conducted into the concentrations and phase association (soluble, colloidal, suspended particulate matter or SPM) of selected pharmaceuticals (propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac, and meclofenamic acid) in river water, effluents from sewage treatment works (STW), and groundwater in the UK.     

Occurrence and distribution of pharmaceuticals in wastewater from households, livestock farms, hospitals and pharmaceutical manufactures

Twenty-four pharmaceuticals were measured in wastewater from 12 municipal wastewater treatment plants (M-WWTPs), four livestock WWTPs (L-WWTPs), four hospital WWTPs (H-WWTPs) and four pharmaceutical manufacture WWTPs (P-WWTPs). The total concentration of pharmaceuticals in the influent samples was highest in the L-WWTPs followed by the P-WWTPs, H-WWTPs and M-WWTPs. The effluents had different patterns of pharmaceuticals than their corresponding influents because of the different fate of each compound in the WWTPs. Non-steroidal anti-inflammatory drugs (NSAIDs) were the most dominant in the influents from the M-WWTPs and P-WWTPs, while antibiotics were dominantly detected in the L-WWTP. In the H-WWTP influents, NSAIDs, caffeine and carbamazepine were dominant. In the P-WWTPs, the distribution of pharmaceuticals in the effluents varied with sampling sites and periods. The M-WWTP influents had the highest daily loads, while the effluents showed somewhat similar levels in all source types.     

Does monensin in chicken manure from poultry farms pose a threat to soil invertebrates?

Monensin is a carboxylic polyether ionophore used in the poultry industry as a coccidiostat. It enters the environment via manure from broiler farms. In spite of its potential presence in the environment, information concerning monensin residues in manure and soil and its toxicity to soil organisms are insufficient. In the present study, two beneficial soil invertebrate species, earthworms (Eisenia andrei) and woodlice (Porcellio scaber), were used to assess the toxicity of monensin. Animals were exposed to a range of monensin concentrations via soil or food. Earthworm reproduction was found to be the most susceptible endpoint (NOEC=3.5 mg kg(-1) dry soil; EC(50)=12.7 mg kg(-1) dry soil), while no adverse effects were recorded in isopods (NOEC?849mgkg(-1) dry soil, NOEC?357mgkg(-1) dry food). The obtained toxicity data were compared with potential concentrations of monensin in soil. In view of this, manure from broiler chickens treated with monensin at a poultry farm was sampled. According to monensin and nitrogen concentrations in the chicken manure and the degradation time of monensin, the predicted environmental concentration (PEC) was calculated. PEC of monensin is around 0.013 mg kg(-1) soil if manure is used after 3 months of composting and 0.05 mg kg(-1) soil if used without storage. Data for earthworm reproduction was used to estimate the predicted no-effect concentration (PNEC). If fresh chicken manure is applied to terrestrial ecosystems, the risk quotient (PEC/PNEC ratio) is above 1, which indicates that monensin might pose an environmental risk under certain conditions. To prevent this, it is strongly recommended to compost chicken manure for several months before using it as fertiliser.     

Accumulation and leaching potential of some pharmaceuticals and potential endocrine disruptors in soils irrigated with wastewater in the Tula Valley, Mexico

The reuse of wastewater for irrigation of agricultural land is a well established practice but introduces many contaminants into the terrestrial environment including pharmaceuticals and personal care products. This study reports the persistence and leaching potential of a group of acidic pharmaceuticals, carbamazepine, and three endocrine disruptors in soils from the Tula Valley in Mexico, one of the largest irrigation districts in the world that uses untreated wastewater. After irrigation of soil columns with fortified wastewater over the equivalent of one crop cycle, between 0% and 7% of the total added amounts of ibuprofen, naproxen, and diclofenac and between 0% and 25% of 4-nonylphenol, triclosan, and bisphenol-A were recovered from the soil profiles. Carbamazepine was more persistent, between 55% and 107% being recovered. Amounts in leachates suggested that movement through the soil was possible for all of the analytes, particularly in profiles of low organic matter and clay content. Analysis of soil samples from the Tula Valley confirmed the general lack of accumulation of the acidic pharmaceuticals (concentrations from below the limit of detection to 0.61 μgkg(-1)) and endocrine disruptors (concentrations from below the limit of detection to 109 μgkg(-1)) despite continual addition through regular irrigation with untreated wastewater; there was little evidence of movement through the soil profiles. In contrast, carbamazepine was present in horizon A of the soil at concentrations equivalent to several years of additions by irrigation (2.6-7.5 μgkg(-1)) and was also present in the deeper horizons. The persistence and mobility of carbamazepine suggested a potential to contaminate groundwater.     

Screening of pharmaceuticals and hormones at the regional scale, in surface and groundwaters intended to human consumption

As part of a regional screening to evaluate the risk, for the health of populations, to certain classes of emerging substances, several families of pharmaceuticals and hormones were looked for in waters intended to drinking. Thus, 52 substances were investigated in 71 surface waters and 70 groundwaters. Results indicate that no water was free of pollutants, regardless of its origin (surface or groundwater) and the season of collect. The pharmaceuticals most frequently detected and with the highest concentration levels were salicylic acid, carbamazepine and acetaminophen. Among hormones, testosterone, androstenedione and progesterone were detected in almost all the samples. Globally the groundwaters were less contaminated than surface waters in regards pharmaceuticals frequencies and levels. On the other side, androgens and progestagens were present with comparable frequencies and levels in both compartments. The risk linked to the presence of these substances on human health is discussed.     

Pharmaceuticals in the river Elbe and its tributaries

Medicinal drugs were found to be ubiquitous in the river Elbe, its tributary the river Saale and in other tributaries at their points of entry into the Elbe. The distribution of concentration peaks along the investigated river stretches provides an indication that they are mainly due to the emission of treated waste water from municipal sewage treatment works. This leads to the conclusion that medicinal substances can be regarded as faecal indicators for water pollution caused by human activity. The main substances found in the Elbe in 1998 were diclofenac, ibuprofen and carbamazepine as well as various antibiotics and lipid regulators in the concentration range of <20-140 ng/l. The more thorough investigations carried out in 1999 and 2000 show that in addition to the drugs (phenazone, isopropyl-phenazone and paracetamol) metabolite concentrations contributed significantly to the total concentration of pharmaceuticals in the Elbe. The metamizole metabolites N-acetyl-4-aminoantipyrine (AAA) and N-formyl-4-aminoantipyrine (FAA) were found in concentrations from <20 to 939 ng/l. A multivariate statistical analysis revealed a high correlation in respect of the distribution of persistent substances. The metoprolol distribution throughout the Saale demonstrated that the tributaries cause either an increase (Weisse Elster, Unstrut, Ilm) or a reduction (Wipper, Bode) in the concentration, depending on the respective load of waste water. Wide scale sampling in Saxony during 2002 showed the ubiquitous occurrence of carbamazepine in surface waters. The ecotoxicological effects of this contamination cannot be assessed at present. This is due to the fact that no legal framework in respect of these medicinal drugs for human consumption has been established and therefore little research and no risk assessment has been carried out. Therefore it is urgently necessary to include at least the quantitatively most significant substances in the new assessment concept of the EC White Paper.     

Irrigation of treated wastewater in Braunschweig, Germany: an option to remove pharmaceuticals and musk fragrances

In this study the fate of pharmaceuticals and personal care products which are irrigated on arable land with treated municipal wastewater was investigated. In Braunschweig, Germany, wastewater has been irrigated continuously for more than 45 years. In the winter time only the effluent of the sewage treatment plant (STP) of Braunschweig is used for irrigation, while during summer digested sludge is mixed with the effluent. In the present case study six wells and four lysimeters located in one of the irrigated agricultural fields were monitored with regard to the occurrence of 52 pharmaceuticals and two personal care products (PPCPs; e.g. betablockers, antibiotics, antiphlogistics, carbamazepine, musk fragrances, iodinated contrast media (ICM) and estrogens). No differences in PPCP pollution of the groundwater were found due to irrigation of STP effluents with and without addition of digested sludge, because many polar compounds do not sorb to sludge and lipophilic compounds are not mobile in the soil-aquifer. Most of the selected PPCPs were never detected in any of the lysimeter or groundwater samples, although they were present in the treated wastewater irrigated onto the fields. In the groundwater and lysimeter samples primarily the ICM diatrizoate and iopamidol, the antiepileptic carbamazepine and the antibiotic sulfamethoxazole were detected up to several mugl(-1), while the acidic pharmaceuticals, musk fragrances, estrogens and betablockers were likely sorbed or transformed while passing the top soil layer. Potential estrogenic effects are likely to disappear after irrigation, since the most potent steroid estrogens were not measurable.     

卡马西平降解菌的筛选分离及其降解机理

药品污染物日益成为新兴污染物研究的重点,药品卡马西平因具有多种药效被广泛使用,在环境中频繁被检出,且浓度较高,不易去除,通常作为环境中药品污染状况的指示化合物。本研究从长期用于去除药品废水的曝气生物滤池中分离出一株细菌YK-6,其能以卡马西平为惟一碳源、氮源和能源生长,通过生理生化以及16S rDNA基因序列分析鉴定并命名为Pseudomonas putida YK-6。该菌株YK-6在pH为7.2、温度30℃、卡马西平初始浓度为20 mg/L、摇床振荡速率为160 r/min的生长条件下培养5 d,对卡马西平的降解率可达54.66%。菌株YK-6对卡马西平的可能降解途径为首先通过生物的氧化作用,将CBZ氧化成CBZ-EP,CBZ-EP经过水解作用转化为CBZ-DiOH,CBZ-DiOH经丙酮酸氧化脱羧及在NADH还原性辅酶的作用下,裂解成苯胺和邻苯甲酸,苯胺和邻苯甲酸再经进一步氧化,直至最终矿化。