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.

     

Soil microbial systems respond differentially to tetracycline,sulfamonomethoxine, and ciprofloxacin entering soil under pot experimental conditions alone and in combination

This study investigated soil microbial responses to the application of tetracycline (TC), sulfamonomethoxine (SMM), and ciprofloxacin (CIP) alone and in combination in a soil culture pot experiment conducted at Hangzhou, China. Multiple approaches were applied for a better and complete depiction. Among the three antibiotics, SMM has a lowest dissipation and shows a most dramatic inhibition on microbial community and metabolism diversity. The combined application (AM) of SMM, CIP, and TC improved the dissipation of each antibiotic; similarly, SMM- and CIP-resistant bacteria showed larger populations in the AM than all single applications. Soils accumulated a large content of NO₃–N at day 20 after multi-antibiotics perturbation. All antibiotics stimulated soil basal respirations and inhibited soil metabolism diversity, whereas the interruption exerted by SMM and AM lasted for a longer time. Six nitrogen-cycling genes including chiA, amoA, nifH, nirK, nirS, and narG were quantified and found to decrease owing to both single- and multi-antibiotics perturbation. Overall, AM was most interruptive for soils, followed by SMM perturbation, while other antibiotics could be less interruptive. These results provide systematic insights into how soil microbial systems would shift under each single- or multi-antibiotics perturbation.     

Nutrient concentrations affect the antimicrobial resistance profiles of cattle manures

Environmental Science and Pollution Research - Antimicrobial resistance (AMR) in cattle is widespread because of the increased use of antibiotics to combat microbial diseases and enhance milk...     

Assessment of soils contamination with veterinary antibiotic residues in Northern Poland using developed MAE-SPE-LC/MS/MS methods

Among the wide range of compounds reaching the soil are the veterinary antimicrobials. Since no regulations regarding acceptable levels of drug concentrations in the environment exist, monitoring tests, particularly concerning soils, are carried out very rarely. This study presents a preliminary assessment of the contamination of agricultural soils in Northern Poland with seven antimicrobial veterinary medicines which has never been carried out before. Veterinary drugs were detected in 54% of the examined soil samples; the most commonly detected drugs were sulfonamides and trimethoprim. The highest indicated concentrations refer to enrofloxacin (57.0 μg kg^?1) and trimethoprim (47.8 μg kg^?1). The presence of these target drugs in the soil environment confirms the need for further monitoring studies. The analytical methods developed in this study are an excellent tool to achieve this goal and allow an estimation of the risk connected with the presence of veterinary antimicrobials in soils.

     

Medical Waste Treatment and Disposal Methods Used by Hospitals in Oregon,Washington, and Idaho

ABSTRACT

This study investigated medical waste practices used by hospitals in Oregon, Washington, and Idaho, which includes the majority of hospitals in the U.S. Environmental Protection Agency's (EPA) Region 10. During the fall of 1993, 225 hospitals were surveyed with a response rate of 72.5%. The results reported here focus on infectious waste segregation practices, medical waste treatment and disposal practices, and the operating status of hospital incinerators in these three states. Hospitals were provided a definition of medical waste in the survey, but were queried about how they define infectious waste. The results implied that there was no consensus about which agency or organization's definition of infectious waste should be used in their waste management programs. Confusion around the definition of infectious waste may also have contributed to the finding that almost half of the hospitals are not segregating infectious waste from other medical waste. The most frequently used practice of treating and disposing of medical waste was the use of private haulers that transport medical waste to treatment facilities (61.5%). The next most frequently reported techniques were pouring into municipal sewage (46.6%), depositing in landfills (41.6%), and autoclaving (32.3%). Other methods adopted by hospitals included Electro-Thermal-Deac-tivation (ETD), hydropulping, microwaving, and grinding before pouring into the municipal sewer. Hospitals were asked to identify all methods they used in the treatment and disposal of medical waste. Percentages, therefore, add up to greater than 100% because the majority chose more than one method. Hospitals in Oregon and Washington used microwaving and ETD methods to treat medical waste, while those in Idaho did not. No hospitals in any of the states reported using irradiation as a treatment technique. Most hospitals in Oregon and Washington no longer operate their incinerators due to more stringent regulations regarding air pollution emissions. Hospitals in Idaho, however, were still operating incinerators in the absence of state regulations specific to these types of facilities.     

Residues of endosulfan in cotton growing area of Vehari,Pakistan: an assessment of knowledge and awareness of pesticide use and health risks

This study is based on self-reported information collected from selected farmers of Vehari District, Punjab, Pakistan, to determine their technical knowledge and awareness about pesticide use and associated environmental and health risks. Moreover, soil contamination by routinely used persistent organochlorine pesticide, endosulfan, was also evaluated. Survey data revealed very low literacy rate (on an average 9th grade education) and technical knowledge (almost missing) of the farmers in Vehari District. The farmers are unable to fully read and understand the instructions about the use of pesticide marked on the containers. They are not fully aware of pesticide persistence and toxicity (73%), unable to identify cotton pests and diseases (86%), and do not know which crop to grow in cotton adjacent fields (100%). Data also revealed that the farmers (100%) do not follow safety measure during pesticide application and are unaware of pesticide toxicity symptoms in human as well as the basic first-aid practices (89%).

Poor literacy rate and lack of technical knowledge of farmers in Vehari regarding pesticide use and handling are posing serious environmental and health risks among the local inhabitants, particularly among farmers. Soil analysis results showed that concentration of α- and β-endosulfan ranged from 0–14 to 0–14.64 μg/mg, respectively. Principal component analysis showed that soil organic matter is the key soil parameter controlling the occurrence and fate of endosulfan under sandy loam soil conditions of Vehari District. There is a serious need of improving technical and environmental knowledge of farmer about pesticide risks on human health in the studied area, in particular, and the entire country in general. Findings are of great use for policymaking in Pakistan to minimize pesticide risks in Pakistan.

     

Drugs in the environment: emission of drugs, diagnostic aids and disinfectants into wastewater by hospitals in relation to other sources--a review.

After administration, pharmaceuticals are excreted by the patients into wastewater. Unused medications are sometimes disposed of in drains. The drugs enter the aquatic environment and eventually reach drinking water if they are not biodegraded or eliminated during sewage treatment. Additionally, antibiotics and disinfectants are supposed to disturb the wastewater treatment process and the microbial ecology in surface waters. Furthermore, resistant bacteria may be selected in the aeration tanks of STPs by the antibiotic substances present. Recently, pharmaceuticals have been detected in surface water, ground water and drinking water. However, only little is known about the significance of emissions from households and hospitals. A brief summary of input by different sources, occurrence, and elimination of different pharmaceutical groups such as antibiotics, anti-tumour drugs, anaesthetics and contrast media as well as AOX resulting from hospital effluent input into sewage water and surface water will be presented.     

Impact of an educational program on knowledge and practice of health care staff toward pharmaceutical waste management in Gaza,Palestine

In health care facilities, pharmaceutical waste is generally discharged down the drain or sent to landfill. Poor knowledge about their potential downstream impacts may be a primary factor for improper disposal behavior. The objective of this study was to determine the impact of an intervention program on knowledge and practice of health care staff regarding pharmaceutical waste management. The study was designed as a pre/posttest intervention study. Total sample size was 530 in the pre-intervention phase, and then a subsample of 69 individuals was selected for the intervention and the post-intervention phases. Paired-sample t test was used to assess the difference between pretest and follow-up test results. A statistically significant improvement in knowledge and practice was achieved (P < 0.001). Poor knowledge and poor practice levels (scores <50%) were found to improve to satisfactory levels (scores ≥75%). Therefore, educational programs could be considered as an effective tool for changing health care staff practice in pharmaceutical waste management.

Implications: In health care facilities, pharmaceutical waste is generally discharged down the drain or sent to landfill. A lack of knowledge about the potential impacts of this type of waste may be a leading factor in improper disposal behavior. Following an educational program, statistically significant improvement in knowledge and practice of health care staff as regards to pharmaceutical waste management (PWM) was achieved. It is thus recommended that authorities implement training-of-trainers (TOT) programs to educate health care staff on PWM and organize refreshment workshops regularly.     

Household bush burning practice and related respiratory symptoms in Grenada,the Caribbean

The practice of household bush burning in Grenada occurs frequently, though it is not well documented. The effects of the emissions from bush burning on respiratory health of the population have never been researched in Grenada. The goal of the study was to measure the frequency of bush burning and to investigate the relationship between bush burning practice and respiratory health in Grenada. In this cross-sectional study, a questionnaire was used to gather information from households in the parishes of St. George and St. Andrew, Grenada. In total, 225 participants were recruited and their responses on household bush burning and respiratory symptoms were analyzed. Self-reported data showed that the practice of bush burning was conducted by 43% (n = 96) of the participants as a regular practice (every month) and 86% (n = 192) of participants stated that their neighbors burn bush regularly. The most common lower respiratory symptom associated with bush burning was dry cough (31.4%). The participants who engage in the practice of bush burning had a statistically significant, higher prevalence of sinusitis symptoms (OR: 2.1, CI 95%: 1.1–3.9) and had slightly higher prevalence of cough (OR: 1.6, CI 95%: 0.9–2.8). Prevalences of physician-diagnosed asthma and sinusitis were 12.3% and 31.2%, respectively. Conducting studies on the health effects of bush burning in different settings and with different practices, such as the household bush burning in our current study, could help to improve public health in the developing world.

Implications:?Household disposal of waste is a significant issue in the developing world. In particular, residential bush burning is a common practice in tropical regions. This study demonstrates that the common practice of bush burning in the Caribbean is associated with respiratory symptoms and demonstrates the need for better management of residential yard waste. Burning of yard waste results in potentially significant exposures to air pollution and therefore alternative disposal practices need to be available. There is a need to increase awareness of the importance of avoiding exposure to the air pollutants generated during bush burning among communities in the Caribbean.     

A comparison of antibiotics,antibiotic resistance genes,and bacterial community in broiler and layer manure following composting

Animal manure is an important source of antibiotics and antibiotic resistance genes (ARGs) in the environment. However, the difference of antibiotic residues and ARG profiles in layer and broiler manure as well as their compost remains unexplored. In this study, we investigated the profiles of twelve antibiotics, seventeen ARGs, and class 1 integrase gene (intI1) in layer and broiler manure, and the corresponding compost at large-scale. Compared with layer manure, broiler manure exhibited approximately six times more residual tetracyclines, especially chlortetracycline. The relative abundances of qnrS and ermA genes in broiler manure were significantly higher than those in layer manure. The concentration of tetracyclines not only had a significantly positive correlation with tetracycline resistance genes (tetA and tetC) but was also positively correlated with quinolone resistance (qepA, qnrB, and qnrS) and macrolide resistance (ermA and ermT). Most ARGs in manure were reduced after composting. However, the relative abundance of sulfonamide resistance gene sul1 increased up to 2.41% after composting, which was significantly higher than that of broiler (0.41%) and layer (0.62%) manure. The associated bacterial community was characterized by high-throughput 16S rRNA gene sequencing. The relative abundances of thermophilic bacteria had significant positive correlations with the abundance of sul1 in compost. The composting has a significant impact on the ARG-associated gut microbes in poultry manure. Variation partitioning analysis indicated that the change of bacterial community compositions and antibiotics contributed partially to the shift in ARG profiles. The results indicate that at industry-scale production broiler manure had more antibiotics and ARGs than layer manure did, and composting decreased most ARG abundances in poultry manure except for sulfonamide resistance genes.

     

Determination of antibiotics in sewage from hospitals, nursery and slaughter house, wastewater treatment plant and source water in Chongqing region of Three Gorge Reservoir in China

Sewage samples from 4 hospitals, 1 nursery, 1 slaughter house, 1 wastewater treatment plant and 5 source water samples of Chongqing region of Three Gorge Reservoir were analyzed for macrolide, lincosamide, trimethoprim, fluorouinolone, sulfonamide and tetracycline antibiotics by online solid-phase extraction and liquid chromatography-tandem mass spectrometry. Results showed that the concentration of ofloxacin (OFX) in hospital was the highest among all water environments ranged from 1.660 μg/L to 4.240 μg/L and norfloxacin (NOR, 0.136-1.620 μg/L), ciproflaxacin (CIP, ranged from 0.011 μg/L to 0.136 μg/L), trimethoprim (TMP, 0.061-0.174 μg/L) were commonly detected. Removal range of antibiotics in the wastewater treatment plant was 18-100% and the removal ratio of tylosin, oxytetracycline and tetracycline were 100%. Relatively higher removal efficiencies were observed for tylosin (TYL), oxytetracycline (OXY) and tetracycline (TET)(100%), while lower removal efficiencies were observed for Trimethoprim (TMP, 1%), Epi-iso-chlorotetracycline (EICIC, 18%) and Erythromycin-H₂O (ERY-H₂O, 24%). Antibiotics were removed more efficiently in primary treatment compared with those in secondary treatment.     

Behaviour and redox sensitivity of antimicrobial residues during bank filtration

The behaviour of residues of antibiotic drugs during bank filtration was studied at a field site in Berlin, Germany, where bank-filtered water is used for the production of drinking water. The neighbouring surface water used for bank filtration is under the influence of treated municipal wastewater. Seven out of 19 investigated antimicrobial residues were found in the surface water with median concentrations between 7 and 151ngL(-1). Out of the seven analytes detected in the surface water only three (anhydroerythromycin, clindamycin and sulfamethoxazole) were found with median concentrations above their limits of quantitation in bank filtrate with a travel time of one month or less. With the exception of sulfamethoxazole, none of the 19 analytes were present in bank filtrate with a residence time larger than one month or in the water-supply well itself. Sulfamethoxazole found with a median concentration of 151ngL(-1) in the surface water was the most persistent of all antimicrobial residues. Nevertheless, it was also removed by more than 98% and only found with a median concentration of 2ngL(-1) in the water-supply well. The degradation of clindamycin and sulfamethoxazole appear to be redox-dependent. Clindamycin was eliminated more efficiently under oxic infiltration conditions while sulfamethoxazole was eliminated more rapidly under anoxic infiltration conditions. A slight preference for an improved degradation under oxic (clarithromycin and roxithromycin) or anoxic (anhydroerythromycin) conditions was also observed for the macrolide antibiotics. Nevertheless, all macrolides were readily removable by bank filtration both under oxic and anoxic conditions.     

Tetracycline removal enhancement with Fe-saturated nanoporous montmorillonite in a tripartite adsorption/desorption/photo-Fenton degradation process

The adsorption and photo-Fenton degradation of tetracycline (TC) over Fe-saturated nanoporous montmorillonite was analyzed. The synthesized samples were characterized using XRD, FTIR, SEM, and XRF analysis, and the adsorption and desorption of TC onto these samples, as well as the antimicrobial activity of TC during these processes, were analyzed at different pH. Initially, a set of adsorption/desorption experiments was conducted, and surprisingly, up to 50% of TC adsorbed was released from Mt structure. Moreover, the desorbed TC had strong antibacterial activity. Then, an acid treatment (for the creation of nanoporous layers) and Fe saturation of the montmorillonite were applied to improve its adsorption and photocatalytic degradation properties over TC. Surprisingly, the desorption of TC from modified montmorillonite was still high up to 40% of adsorbed TC. However, simultaneous adsorption and photodegradation of TC were detected and almost no antimicrobial activity was detected after 180 min of visible light irradiation, which could be due to the photo-Fenton degradation of TC on the modified montmorillonite surface. In the porous structures of modified montmorillonite high, ˙OH radicals were created in the photo-Fenton reaction and were measured using the Coumarin technique. The ˙OH radicals help the degradation of TC as proposed in an oxidation process. Surprisingly, more than 90% of antimicrobial activity of the TC decreased under visible light (after 180 min) when desorbed from nanoporous Fe-saturated montmorillonite compared to natural montmorillonite. To the best of our knowledge, this is the first time that such a high TC desorption rate from an adsorbent with the least residual antimicrobial activity is reported which makes nanoporous Fe-saturated montmorillonite a perfect separation substance of TC from the environment.

     

Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen with indigenous arbuscular mycorrhizal fungal mixture induces changes in heavy metal and nutrient uptake

Plants of the Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen (Brassicaceae) inoculated or not with indigenous arbuscular mycorrhizal (AM) fungal mixture were grown in a highly Cd, Zn and Pb contaminated substrate in order to evaluate the functionality of symbiosis and assess the possible impact of AM colonisation on heavy metal uptake and tolerance. The results suggest AM development in the metal hyperaccumulating T. praecox is favoured at elevated nutrient demands, e.g. during the reproductive period. AM colonisation parameters positively correlated with total soil Cd and Pb. Colonised plants showed significantly improved nutrient and a decreased Cd and Zn uptake as revealed by TRXRF, thus confirming the functionality of the symbiosis. Reduced heavy metal uptake, especially at higher soil metal contents, indicates a changed metal tolerance strategy in colonised T. praecox plants. This is to our knowledge the first report on AM colonisation of the Zn, Cd and Pb hyperaccumulator T. praecox in a greenhouse experiment.     

Analysis,occurrence and fate of commonly used pharmaceuticals and hormones in the Buyukcekmece Watershed,Turkey

The occurrence of 14 mostly used pharmaceuticals from different classes (antibiotics, β-blockers, non-steroidal anti-inflammatory drugs, and stimulant) and hormones in surface water in Istanbul, Turkey was investigated in this study. An important drinking water source, Buyukcekmece Lake and main rivers flowing into the lake were selected for the monitoring of the compounds. Sampling was conducted five different times in a year in order to observe seasonal changes. A rapid, robust and sensitive method using solid phase extraction and ultra-performance liquid chromatograph coupled with triple quadrupole tandem mass spectrometer was established for quantification of both pharmaceuticals and hormones. Limit of quantifications were between 0.5 and 1.1 ng L^?1. Recoveries were between 72–119% and 61–98% for ultra-pure water and for surface water, respectively. All selected compounds were detected at least once in the samples. Some pharmaceuticals were detected as high as a few of micrograms per liter levels in the rivers. Most frequently detected compounds were caffeine and antibiotics (amoxicillin, ciprofloxacin, erythromycin and sulfamethoxazole). Synthetic hormone (17α-ethynylestradiol) was detected only 4 times corresponding least detected compound in whole sampling period. Field data confirms that amoxicillin is more prone to degradation with respect to other antibiotics. Estrone and 17-β estradiol are converted to estriol by natural processes in surface water.     

Occurrence,distribution, and risk assessment of antibiotics in the Songhua River in China

The occurrence, distribution, and risk assessment of antibiotics in freshwater systems are receiving global attention, because of their impact on the environment and human health. However, few studies have focused on this topic in Northeast China and its Songhua River, the third-largest river in China. This study investigated the occurrence and distribution of 12 antibiotics, including three cephalosporins (cefazolin, cefmetazole, cefotaxime), three macrolides (azithromycin, clarithromycin, roxithromycin), three fluoroquinolones (ofloxacin, norfloxacin, flumequine), and three sulfonamides (sulfadiazine, sulfapyridine, sulfamethoxazole) in the mainstream and tributaries of the Songhua River. A total of 152 surface water samples were collected in January, May, July, and October 2016. These samples were analyzed using solid-phase extraction (SPE) and ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The results indicated the wide use of all 12 antibiotics in the mainstream of the Songhua River. Sulfamethoxazole and cefazolin were the dominant antibiotics, with maximum concentrations of 73.1 and 65.4 ng L^?1, respectively. Other antibiotics were present at mean concentrations below 15 ng L^?1, except cefmetazole, present at a mean concentration of 35.6 ng L^?1. The spatial distribution of antibiotics showed that unbalanced regional development may lead to the distribution pattern of the antibiotics in the tributaries and the mainstream. Thus study also assessed the seasonal variation of antibiotics in urban surface water; cephalosporin, sulfonamide, fluoroquinolone, and macrolide concentrations were significantly higher during the icebound season than during non-icebound season. This may be due to the low temperature and water flow of the river in winter. Risk assessment showed that azithromycin, clarithromycin, roxithromycin, flumequine, and sulfamethoxazole posed a low or median risk to the aquatic organisms in the mainstream. The potential risks created by antibiotics to the aquatic environment should not be neglected in the Songhua River. The potential risks created by antibiotics to the aquatic environment should not be neglected in the Songhua River.

     

Silicon and Rhizophagus irregularis: potential candidates for ameliorating negative impacts of arsenate and arsenite stress on growth,nutrient acquisition and productivity in Cajanus cajan (L.) Millsp. genotypes

Arsenic (As) gets accumulated in plants via phosphorous transporters and water channels and interferes with nutrient and water uptake, adversely affecting growth and productivity. Although, Si and AM have been reported to combat arsenic stress, their comparative and interactive roles in ameliorating As V and As III toxicities have not been reported. Study evaluated effects of Si and Rhizophagus irregularis on growth, As uptake and yield under arsenate and arsenite stress in two pigeonpea genotypes (metal tolerant—Pusa 2002 and metal sensitive—Pusa 991). Higher As accumulation and translocation was observed in As III treated roots of Pusa 991 than those of Pusa 2002 when compared with As V. Roots were more negatively affected than shoots which led to a significant decline in nutrient uptake, leaf chlorophylls, and yield, with As III inducing more negative effects. Pusa 2002 established more effective mycorrhizal symbiosis and had higher biomass than Pusa 991. Si was more effective in inducing shoot biomass while AM inoculation significantly improved root biomass. AM enhanced Si uptake in roots and leaves in a genotype dependent manner. Combined application of Si and AM were highly beneficial in improving leaf water status, chlorophyll pigments, biomass, and productivity. Complete amelioration of negative impacts of both concentrations of As V and lower concentration of As III were recorded under +Si +AM in Pusa 2002. Results highlighted great potential of Si in improving growth and productivity of pigeonpea through R. irregularis under As V and As III stresses.

     

Residual veterinary antibiotics in swine manure from concentrated animal feeding operations in Shandong Province, China

The scientific interest in the occurrence and fate of antibiotics in animal husbandry has increased during the past decades because of the emergence and development of antimicrobial resistance in pathogenic bacteria. This study developed a method for simultaneous detection of five sulfonamides, three tetracyclines and one macrolide in swine manure with stable recoveries (73.0-110.6%) and high sensitivity (limit of quantification <90 μg kg⁻¹). Thereafter, a total of 126 swine manure samples, collected from 21 concentrated animal feeding operations (CAFOs) in Shandong Province of China during summer and winter, were analyzed. The potential influences of different sampling seasons, swine types and food sources on residual antibiotic concentrations were examined in detail. The maximum concentration of residual antibiotic could reach up to 764.4 mg kg⁻¹ (chlortetracycline), and the detection frequencies were 84.9-96.8% for tetracyclines, 0.8-51.6% for sulfonamides and 4.8% for macrolide. These data reveal that antibiotics were extensively used in CAFOs in this district and the manure may act as a non-specific source of antibiotic residue in farmlands and aquatic environments.     

Do antibiotics have environmental side-effects? Impact of synthetic antibiotics on biogeochemical processes

Antibiotic use in the early 1900 vastly improved human health but at the same time started an arms race of antibiotic resistance. The widespread use of antibiotics has resulted in ubiquitous trace concentrations of many antibiotics in most environments. Little is known about the impact of these antibiotics on microbial processes or “non-target” organisms. This mini-review summarizes our knowledge of the effect of synthetically produced antibiotics on microorganisms involved in biogeochemical cycling. We found only 31 articles that dealt with the effects of antibiotics on such processes in soil, sediment, or freshwater. We compare the processes, antibiotics, concentration range, source, environment, and experimental approach of these studies. Examining the effects of antibiotics on biogeochemical processes should involve environmentally relevant concentrations (instead of therapeutic), chronic exposure (versus acute), and monitoring of the administered antibiotics. Furthermore, the lack of standardized tests hinders generalizations regarding the effects of antibiotics on biogeochemical processes. We investigated the effects of antibiotics on biogeochemical N cycling, specifically nitrification, denitrification, and anammox. We found that environmentally relevant concentrations of fluoroquinolones and sulfonamides could partially inhibit denitrification. So far, the only documented effects of antibiotic inhibitions were at therapeutic doses on anammox activities. The most studied and inhibited was nitrification (25–100 %) mainly at therapeutic doses and rarely environmentally relevant. We recommend that firm conclusions regarding inhibition of antibiotics at environmentally relevant concentrations remain difficult due to the lack of studies testing low concentrations at chronic exposure. There is thus a need to test the effects of these environmental concentrations on biogeochemical processes to further establish the possible effects on ecosystem functioning.