Occurrence profiling, risk assessment, and correlations of antimicrobials in surface water and groundwater systems in Southwest Nigeria.

The presence of antimicrobials in water has grown into a major global health concern. This study thus focused on the presence, ecological implications, and potential health risks associated with nine antimicrobials: five antibiotics (ampicillin, chloramphenicol, ciprofloxacin, metronidazole, and tetracycline) and four parabens (methylparaben, ethylparaben, propylparaben, and butylparaben) in surface water and groundwater samples collected from three Southwestern States in Nigeria (Osun, Oyo, and Lagos States). These antimicrobials were widely detected across the three States with ciprofloxacin being the most dominant having maximum average concentrations of 189 µg L-1 and 319 µg L-1 in surface water and groundwater respectively. The range of average concentrations of antibiotics in surface water are 47.3-235 µg L-1 (Osun), 27.9-166 µg L-1 (Oyo) and 52.1-159 µg L-1 (Lagos). For groundwater, it is 35.3-180 µg L-1 (Osun), 26.5-181 µg L-1 (Oyo) and 32.3-319 µg L-1 (Lagos). The average concentrations of all parabens were 32.4-153 µg L-1, 53.4-80.1 µg L-1, and 83.2-132 µg L-1 for surface water and 46.7-55.7 µg L-1, 53-117 µg L-1, and 62.4-118 µg L-1 for groundwater in Osun, Oyo, and Lagos States respectively. Methylparaben was most frequently detected paraben with average concentrations of 153 µg L-1 and 117 µg L-1 in surface water and groundwater respectively. The measured environmental concentrations of these antimicrobials pose a significant ecological risk while those of ciprofloxacin and ampicillin pose a high health risk to all population groups studied. The average concentrations of antibiotics investigated in this study exceeded their threshold values for Predicted No-Effect Concentrations (PNEC) associated with resistance selection, except for tetracycline.

Distribution and toxicity of dihydroxybenzenes in drinking water sources in Nigeria.

This study provides, for the first time, data on the distribution and toxicity of catechol (CAT) and hydroquinone (HQ) in drinking water sources from Africa. Groundwater (boreholes and hand-dug wells) and surface water in three Southwestern States in Nigeria served as sampling sites. The concentrations of CAT and HQ in groundwater and surface water were determined throughout a period of 12 months, evaluating the effects of seasonal variation (rainy and dry seasons). Mean concentrations of CAT in water samples were higher than those of HQ. In this study, CAT was more frequently detected, with its mean concentration in groundwater samples higher in the rainy season (430 µg L-1) than in the dry season (175 µg L-1). Multivariate analysis using the Principal Component Analysis Software suggests that in most sample sites, CAT and HQ in water samples were from entirely different anthropogenic sources. The most impacted population groups were the toddlers and infants. Similarly, maximum and median concentrations of CAT in water samples pose serious risks to Daphnia at both acute and chronic levels. The results from this study suggest the need for further control of these dihydroxybenzenes through regular monitoring and removal from drinking water during treatment.

Pollution and risk assessment of phenolic compounds in drinking water sources from South-Western Nigeria.

This study reports the occurrence and risk assessment of 2,4-dinitrophenol (2,4-DNP), phenol (PHE), and 2,4,6-trichlorophenol (2,4,6-TCP) in drinking water sources in three south-western States in Nigeria (Osun, Oyo, and Lagos). Groundwater (GW) and surface water (SW) were collected during dry and rainy seasons of a year. The detection frequency of the phenolic compounds followed the trend Phenol > 2,4-DNP > 2,4,6-TCP. The mean concentrations of 2,4-DNP, Phenol, and 2,4,6-TCP in GW/SW samples from Osun State were 639/553 µg L-1, 261/262 µg L-1, and 169/131 µg L-1 during the rainy season and 154/7 µg L-1, 78/37 µg L-1, and 123/15 µg L-1 during the dry season, respectively. In Oyo State, the mean concentrations were 165/391 µg L-1 for 2,4-DNP and 71/231 µg L-1 for Phenol in GW/SW samples, respectively, during the rainy season. Generally, in the dry season, these values decreased. In any case, these concentrations are higher than those previously reported in water from other countries. The concentration of 2,4-DNP in water posed serious ecological risks to Daphnia on the acute scale while it was algae on the chronic scale. Estimated daily intake and hazard quotient calculations suggest that 2,4-DNP and 2,4,6-TCP in water pose serious toxicity concerns to humans. Additionally, the concentration of 2,4,6-TCP in water from Osun State in both seasons of the year and in both groundwater and surface water poses significant carcinogenic risks to persons ingesting water from these sources in the State. Every exposure group studied were at risk from ingesting these phenolic compounds in water. However, this risk decreased with increasing age of the exposure group. Results from the principal component analysis indicate that 2,4-DNP in water samples is from an anthropogenic source different from that for Phenol and 2,4,6-TCP. There is a strong need to treat water from GW and SW systems in these States before ingesting while assessing their quality regularly.

Recent perspective of antibiotics remediation: A review of the principles, mechanisms, and chemistry controlling remediation from aqueous media.

Antibiotic pollution is an ever-growing concern that affects the growth of plants and the well-being of animals and humans. Research on antibiotics remediation from aqueous media has grown over the years and previous reviews have highlighted recent advances in antibiotics remediation technologies, perspectives on antibiotics ecotoxicity, and the development of antibiotic-resistant genes. Nevertheless, the relationship between antibiotics solution chemistry, remediation technology, and the interactions between antibiotics and adsorbents at the molecular level is still elusive. Thus, this review summarizes recent literature on antibiotics remediation from aqueous media and the adsorption perspective. The review discusses the principles, mechanisms, and solution chemistry of antibiotics and how they affect remediation and the type of adsorbents used for antibiotic adsorption processes. The literature analysis revealed that: (i) Although antibiotics extraction and detection techniques have evolved from single-substrate-oriented to multi-substrates-oriented detection technologies, antibiotics pollution remains a great danger to the environment due to its trace level; (ii) Some of the most effective antibiotic remediation technologies are still at the laboratory scale. Thus, upscaling these technologies to field level will require funding, which brings in more constraints and doubts patterning to whether the technology will achieve the same performance as in the laboratory; and (iii) Adsorption technologies remain the most affordable for antibiotic remediation. However, the recent trends show more focus on developing high-end adsorbents which are expensive and sometimes less efficient compared to existing adsorbents. Thus, more research needs to focus on developing cheaper and less complex adsorbents from readily available raw materials. This review will be beneficial to stakeholders, researchers, and public health professionals for the efficient management of antibiotics for a refined decision.

Antibiotic resistomes and their chemical residues in aquatic environments in Africa.

The aquatic environment is a hotspot for the transfer of antibiotic resistance to humans and animals. Several reviews have put together research efforts on the presence and distribution of antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic chemical residue (ACRs) in food, hospital wastewater, and even in other aquatic environments. However, these reports are largely focused on data from developed countries, while data from developing countries and especially those in Africa, are only marginally discussed. This review is the first effort that distills information on the presence and distribution of ARGs and ACRs in the African aquatic environments (2012-2021). This review provides critical information on efforts put into the study of ARB, ARGs, and ACRs in aquatic environments in Africa through the lens of the different sub-regions in the continent. The picture provided is compared with those from some other continents in the world. It turns out that the large economies in Africa (South Africa, Nigeria, Tunisia, Kenya) all have a few reports of ARB and ARGs in their aquatic environment while smaller economies in the continent could barely provide reports of these in their aquatic environment (in most cases no report was found) even though they have some reports on resistomes from clinical studies. Interestingly, the frequency of these reports of ARB and ARGs in aquatic environments in Africa suggests that the continent is ahead of the South American continent but behind Europe and Asia in relation to providing information on these contaminants. Common ARGs found in African aquatic environment encode resistance to sulfonamide, tetracycline, ß-lactam, and macrolide classes of antibiotics. The efforts and studies from African scientists in eliminating ARB and ARGs from the aquatic environment in Africa are also highlighted. Overall, this document is a ready source of credible information for scientists, policy makers, governments, and regional bodies on ARB, ARGs, and ACRs in aquatic environments in Africa. Hopefully, the information provided in this review will inspire some necessary responses from all stakeholders in the water quality sector in Africa to put in more effort into providing more scientific evidence of the presence of ARB, ARGs, and ACRs in their aquatic environment and seek more efficient ways to handle them to curtail the spread of antibiotic resistance among the population in the continent. This will in turn, put the continent on the right path to meeting the United Nations Sustainable Development Goals #3 and #6, which at the moment, appears to be largely missed by most countries in the continent.

Occurrence and human exposure assessment of parabens in water sources in Osun State, Nigeria.

Parabens are chemicals extensively used in pharmaceuticals, cosmetics, personal hygiene and food products as preservatives. They are classified as emerging contaminants with endocrine-disrupting capability. In this study, the concentrations of Methylparaben (MeP), Ethylparaben (EtP), Propylparaben (PrP) and Butylparaben (BuP) were obtained from groundwater, surface-water and packaged water samples collected from urban and rural areas of Osun State, Nigeria using HPLC-UV equipment. Data obtained were subjected to descriptive (Mean ± SD), inferential (Kruskal-Wallis test) and multivariate analyses. MeP had the highest average concentration of 163 and 68 µg L-1 in surface water and groundwater respectively while concentrations of MeP, EtP, PrP and BuP were higher than previously reported in other countries. Methylparaben had the highest detection frequencies (88.0 and 50.0%) followed by BuP (69.0 and 50.0%) in surface water and groundwater respectively. No significant difference was observed for concentrations of parabens in groundwater samples in urban and rural sampling sites, suggesting that people living around these sites are equally exposed to any health implications from the use of paraben-polluted potable water. Principal Component Analysis (PCA) data suggest that the pairs MeP & EtP, PrP & BuP (in surface water samples) and MeP, EtP, & PrP (in groundwater samples) are from similar pollution sources. Ecological risk assessment using Algae, Fish, and Daphnia suggests Daphnia as the most sensitive organism while BuP and PrP show the highest health risk. Human exposure assessment showed that higher overall median estimated daily intake (EDI) values for groundwater were observed in infants (1.71 µg kg-1 bw day-1, ∑PBs) compared to toddlers (1.03 µg kg-1 bw day-1, ∑PBs), children (0.64 µg kg-1 bw day-1, ∑PBs), teenagers (0.51 µg kg-1 bw day-1, ∑PBs) and adults (0.62 µg kg-1 bw day-1, ∑PBs). Although these values are below limits set in a few countries, potential bioaccumulation could lead to severe health consequences.

Toxicity and removal of parabens from water: A critical review.

Parabens are biocides used as preservatives in food, cosmetics and pharmaceuticals. They possess antibacterial and antifungal activity due to their ability to disrupt cell membrane and intracellular proteins, and cause changes in enzymatic activity of microbial cells. Water, one of our most valuable natural resource, has become a huge reservoir for parabens. Halogenated parabens from chlorination/ozonation of water contaminated with parabens have shown to be even more persistent in water than other types of parabens. Unfortunately, there is dearth of data on their (halogenated parabens) presence and fate in groundwater which serves as a major source of drinking water for a huge population in developing countries. An attempt to neglect the presence of parabens in water will expose man to it through ingestion of contaminated food and water. Although there are reviews on the occurrence, fate and behaviour of parabens in the environment, they largely omit toxicity and removal aspects. This review therefore, presents recent reports on the acute and chronic toxicity of parabens, their estrogenic agonistic and antagonistic activity and also their relationship with antimicrobial resistance. This article further X-rays several techniques that have been employed for the removal of parabens in water and their drawbacks including adsorption, biodegradation, membrane technology and advanced oxidation processes (AOPs). The heterogeneous photocatalytic process (one of the AOPs) appears to be more favoured for removal of parabens due to its ability to mineralize parabens in water. However, more work is needed to improve this ability of heterogeneous photocatalysts. Perspectives that will be relevant for future scientific studies and which will drive policy shift towards the presence of parabens in our drinking waters are also offered. It is hoped that this review will elicit some spontaneous actions from water professionals, scientists and policy makers alike that will provide more data, effective technologies, and adaptive policies that will address the growing threat of the presence of parabens in our environment with respect to human health.

Pre-and-post-operative aversion among men whose partners had caesarean delivery in a patriarchal setting.

Objectives: The study evaluated pre and post-operative perception and aversion to caesarean delivery (CD) among men whose partners underwent the procedure. Design: A multicentre cross-sectional study. Setting: Two tertiary and two secondary health facilities. Participants: Men whose partners underwent CD at the study sites. Methods: Participants were recruited by purposive sampling, data collection was through interaction via an interviewer-administered questionnaire first immediately the decision for CD was made and thereafter on the third postoperative day. Men whose partners had vaginal delivery were excluded from the study and data management was with SPSS version 21.0 while p<0.05 was significant. Results: Awareness about CD was 84.0% mainly through the healthcare workers (42.1%) and the female partner (34.1%); 88.0% of participants recommended CD for medically-indicated reasons. The greatest influence on consent was the male partner (48.8%). The major pre-operative concerns were limitation of family size (34.7%) and fear of repeat CD (34.0%). Pre-operative perceptions of CD included being expensive (60.7%), fear of the procedure (48.0%), fear of complications (45.3%) and longer hospital stay (44.0%). Aversion to CD was 30.0% pre and 5.3% post-operation; predictors of aversion were history of previous surgery among male or female partner and awareness about CD. However, there were reductions in negative perception and aversion post-operation. Conclusion: The high negative perception and aversion to CD among male partners were reduced post-operation. Healthcare workers should address the concerns and negative perceptions about CD and prioritize patient-friendly experiences during surgical operations. Funding: Funding was by the researchers; no grant or external support was received for the study.

Elemental Distribution and Health Risk Assessment of the Edible Fruits of Two Ficus Species, Ficus sycomorus L. and Ficus burtt-davyi Hutch.

Edible fruits of two indigenous medicinal Ficus species (Ficus sycomorus L. and Ficus burtt-davyi Hutch) collected from eight different sites in South Africa were assessed for nutritional value, elemental concentration, and the possible risk associated with their consumption. The metal concentrations in the fruits and growth soil were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The results showed elemental concentrations in the fruits to contribute significantly to recommended dietary allowances and were found to be in decreasing order of Ca > Mg > Fe > Zn > Mn > Cu > Cr and Ca Ëƒ Mg Ëƒ Fe Ëƒ Mn Ëƒ Zn Ëƒ Cu for both F. sycomorus and F. burtt-davyi fruits. The results for proximate composition of F. sycomorus fruits were (in %) 55.8 for moisture, 25.3 for carbohydrates, 5.6 for protein, 8.9 for fats, 55.8 for crude fiber, and 4.4 for ash; for F. burtt-davyi fruits, it was (in %) 78.9 for carbohydrates, 5.0 for protein, 8.4 for lipids, 4.0 for crude fiber, and 3.7 for ash. The health risk assessment showed target hazard quotient, and hazard indices for all the studied heavy metals in the fruits for all the sites were to be less than one and the target carcinogenic risk values to be within the acceptable regulatory cancer risk range. This study confirms that the fruits of F. sycomorus and F. burtt-davyi are safe for human consumption due to low non-carcinogenic and carcinogenic adverse health effects.

Risk assessment and source identification of heavy metal contamination by multivariate and hazard index analyses of a pipeline vandalised area in Lagos State, Nigeria.

Petroleum contamination is a significant contributor of elevated level of toxic heavy metals, which are of great concern to human health, due to their non-biodegradable nature. Agaye community has experienced frequent gasoline spills due to pipeline vandalisation, resulting in the contamination of soil and water sources. The concentrations of metals (Cd, Cr, Cu, Mn, Ni, Pb, V and Zn) in groundwater, surface-water and soil were determined from a total of 216 samples acquired bi-monthly for two years by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) to evaluate the impact of oil spills. Multivariate analyses using principal component analysis (PCA) and cluster analysis (CA) were also used to study the interactions between metals and identify the possible sources of contamination. The concentrations of heavy metals in soil and water samples (surface and groundwater) were in decreasing order of Mn > Ni > Zn > Cu > V > Cr > Pb > Cd and Ni > Zn > V > Cu > Mn > Pb > Cr > Cd respectively. Ni concentration ranged from 0.42-8.05 mg kg-1 and 0.10-2.85 mg L-1 for soil and groundwater respectively. Ni and V were more enhanced (P < 0.05) in soil samples. This study showed that there was significant relationship between elevated levels of Cr, Cu, Ni and Zn and oil spillage, due to petroleum spills and that residents were vulnerable to and at greater risk of non-carcinogenic hazards if they consumed groundwater. Multivariate analyses showed significant anthropogenic intrusions of two diagnostic heavy metals (Ni and V) for petroleum contamination in the soils and water sources.

Cytotoxic activity of the bioactive principles from Ficus burtt-davyi.

Ficus burtt-davyi (Moraceae) is a medicinal plant species indigenous to Southern Africa. In this study, a phytochemical and cytotoxic investigation on F. burtt-davyi was conducted to evaluate its ethno-medicinal use. The phytochemical study of the fruits yielded triterpenoids (lupeol and α-amyrin). The cytotoxic evaluation was done on the methanolic extracts and selected compounds, lupeol, α-amyrin, lupeol acetate and (+)-catechin isolated from F. burtt-davyi stem bark and fruits. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay was carried out against two human cancer cell lines, breast adenocarcinoma (MCF-7) and colorectal adenocarcinoma (Caco-2), and normal human embryonic kidney cells (HEK293). The methanol extract from the stem bark was significantly cytotoxic to MCF-7 and Caco-2 cell lines (p < 0.05) in a concentration-dependent manner with IC50 values of 6.6 and 8.1 µg mL-1, respectively relative to the control. Lupeol and (+)-catechin showed cytotoxic activity against MCF-7 cell lines with IC50 values of 22.6 and 29.8 µg mL-1, respectively and greater cytotoxic activity against Caco-2 cell lines with IC50 values of 10.7 and 9.0 µg mL-1, respectively. Data from this study suggests that F. burtt-davyi exhibits cytotoxicity with no significant inhibitory effects against HEK293. The results also indicate that (+)-catechin and lupeol, the most abundant bioactive principles in the stem bark, are responsible for the synergistic cytotoxic effects against tested human cancer cell lines. This study provides evidence on the pharmaceutical potential of the medicinal plant, F. burtt-davyi, as a chemotherapeutic agent against cancer.

Nutritional evaluation, bioaccumulation and toxicological assessment of heavy metals in edible fruits of FicussurForssk (Moraceae).

Ficussur (Moraceae) is an indigenous medicinal plant with a wide distribution in Africa. In this study, the nutritional potential fruit of this indigenous plant to meet domestic food demands and reduce food insecurity in KwaZulu-Natal. South Africa, was investigated. The proximate composition and concentrations of metals in the edible fruits collected from eight different sites in KwaZulu-Natal were determined to assess for nutritional value and the concentrations of metals in the growth soil was determined to evaluate the impact of soil quality on elemental uptake. The fruits contained high levels of moisture (88.8%) and carbohydrates (65.6%). The concentrations of elements in the fruits were found to be in decreasing order of Ca>Mg >Fe >Zn>Cu >Mn> Se with low levels of toxic metals (As, Cd, Co and Pb). This study shows that the consumption of the fruits of F. sur can contribute positively to the nutritional needs of rural communities in South Africa for most essential nutrients without posing the risk of adverse health effects.

Modeling the biotransformation of trimethoprim in biological nutrient removal system.

A pilot scale biological nutrient removal (BNR) process, batch experiments and modeling exercises were employed to investigate the removal and biotransformation of trimethoprim (TMP) in a BNR activated sludge process. The concentrations of the active microbial groups - ammonia oxidizing bacteria (AOB), ordinary heterotrophic organisms (OHOs) and polyphosphate accumulating organisms (PAOs) - in the BNR bioreactor were quantified through modeling of the pilot bioreactor. The overall TMP removal efficiency for the pilot BNR process was 64 ± 14% while the TMP biotransformation efficiencies in the anaerobic, anoxic and aerobic zones were 22 ± 20%, 27 ± 8% and 36 ± 5% respectively. Batch tests with and without nitrification inhibition showed that AOB played a role in the biotransformation of TMP in BNR activated sludge. A pseudo first order model which incorporated the contributions of PAOs, OHOs and AOB to the overall biodegradation of TMP was found to describe the biodegradation of TMP in batch tests with and without nitrification inhibition. This model showed that PAOs, OHOs and AOB contributed towards the biotransformation of TMP in aerobic BNR activated sludge with the biotransformation rate constants following the trend of kAOB > kOHOs > kPAOs.

Relationship between gross placental characteristics and perinatal outcome of low-risk singleton deliveries.

BACKGROUND: Gross examination of the placenta may provide useful insight into the aetiology of newborn and maternal complications. A review of literature revealed only a few epidemiological studies that determined the relationships between placental abnormalities, gestational age and occurrence of adverse outcome in babies of healthy pregnant women in our region. PATIENTS AND METHODS: A prospective cross-sectional study was conducted at the Department of Obstetrics and Gynecology of University of Ilorin Teaching Hospital, between 1 st February and August 2013. Pregnant women in labour at ≥28 weeks' gestational age with singleton pregnancies were recruited. Gross examination of the placenta and umbilical cord after delivery were performed. RESULTS: Four hundred and twenty-eight singleton deliveries were studied. The average placental weight was 580.8 ± 130.6 g (range = 125-1500 g). The mean values of the umbilical cord length and width were 52.7 ± 10.5 cm and 1.96 ± 1.11 cm, respectively. Placental abnormalities occurred in 1.2%. The umbilical cord was centrally inserted in 290 (67.8%), marginally in 31% of cases. There was significant but weak positive correlation between the placental weight, birth weight and gestational age at 40 weeks (P ≤ 0.001, r = 0.356). Placental weight was directly related to birth weight (P < 0.0001, r = 0.244) and greater in babies with congenital abnormalities (P = 0.002). CONCLUSIONS: There was an association between placental parameters and foetal outcome at birth. Placental weight was positively correlated with birth weight, gestational age and occurrence of congenital abnormalities.

CHEMICAL CONSTITUENTS AND IN VITRO ANTIOXIDANT ACTIVITY OF CRUDE EXTRACTS AND COMPOUNDS FROM LEAVES AND STEM BARK OF FICUS BURTT-DAVYI.

Ficus buit-davyi, (Moraceae), is an endemic species of South Africa. In this study, a phytochemical analysis of the leaves and stem bark of F. burt-davyi resulted in the isolation of five triterpenes (lupeol, lupeol acetate, ß-sitosterol, stigmasterol and campesterol), one carotenoid (lutein), a pheophytin (phytyl-7-ethyl-25- (methoxycarbonyl)-3,8,13,17-tetramethyl-26-oxo- 12-vinyl-17,18-dihydro-2,20-ethanoporphyrin- 1 8-propanoate or pheophytin a) and one flavonoid (+)-catechin). The in viti antioxidant study of the methanol extracts of leaves and stem bark, (+)-catechin and pheophytin a using the 1,1-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, ferric reducing antioxidant power (FRAP) assay and hydrogen peroxide (H202) assay showed significantly higher (p < 0.05) antioxidant activity for the methanol extract of the stem bark than the leaves, with IC55 values (in µg/mL) of 58.28 ? 5.05 for DPPH, 46.09 ± 0.06 for FRAP and 151.03 ± 1.60 pg/mL for H202,. The results suggest that the plant can be used as a therapeutic agent in alternative medicine for oxidative stress related degenerative diseases.

Impact of wastewater treatment configuration and seasonal conditions on thyroid hormone disruption and stress effects in Rana catesbeiana tailfin.

Improved endocrine disrupting compound (EDC) removal is desirable in municipal wastewater treatment plants (MWWTPs) although increased removal does not always translate into reduced biological activity. Suitable methods for determining reduction in biological activity of effluents are needed. In order to determine which MWWTPs are the most effective at removing EDC activities, we operated three configurations of pilot sized biological reactors (conventional activated sludge, CAS; nitrifying activated sludge, NAS; and biological nutrient removal, BNR) receiving the same influent under simulated winter and summer conditions. As frogs are model organisms for the study of thyroid hormone (TH) action, we used the North American species Rana catesbeiana in a cultured tadpole tailfin (C-fin) assay to compare the effluents. TH-responsive (thyroid hormone receptors alpha (thra) and beta (thrb)) and stress-responsive (superoxide dismutase, catalase, and heat shock protein 30) mRNA transcript levels were examined. Effluents infrequently perturbed stress-responsive transcript abundance but thra/thrb levels were significantly altered. In winter conditions, CAS caused frequent TH perturbations while BNR caused none. In summer conditions, however, BNR caused substantial TH perturbations while CAS caused few. Our findings contrast other studies of seasonal variations of EDC removal and accentuate the importance of utilizing appropriate biological readouts for assessing EDC activities.