Edmund John Pool

The effectiveness of sewage treatment processes to remove faecal pathogens and antibiotic residues

Pathogens and antibiotics enter the aquatic environment via sewage effluents and may pose a health risk to wild life and humans. The aim of this study was to determine the levels of faecal bacteria, and selected antibiotic residues in raw wastewater and treated sewage effluents from three different sewage treatment plants in the Western Cape, South Africa. Sewage treatment plant 1 and 2 use older technologies, while sewage treatment plant 3 has been upgraded and membrane technologies were incorporated in the treatment processes. Coliforms and Escherichia coli (E. coli) were used as bioindicators for faecal bacteria. A chromogenic test was used to screen for coliforms and E. coli. Fluoroquinolones and sulfamethoxazole are commonly used antibiotics and were selected to monitor the efficiency of sewage treatment processes for antibiotic removal. Enzyme Linked Immunosorbent Assays (ELISAs) were used to quantitate antibiotic residues in raw and treated sewage. Raw intake water at all treatment plants contained total coliforms and E. coli. High removal of E. coli by treatment processes was evident for treatment plant 2 and 3 only. Fluoroquinolones and sulfamethoxazole were detected in raw wastewater from all sewage treatment plants. Treatment processes at plant 1 did not reduce the fluoroquinolone concentration in treated sewage effluents. Treatment processes at plant 2 and 3 reduced the fluoroquinolone concentration by 21% and 31%, respectively. Treatment processes at plant 1 did not reduce the sulfamethoxazole concentration in treated sewage effluents. Treatment processes at plant 2 and 3 reduced sulfamethoxazole by 34% and 56%, respectively. This study showed that bacteria and antibiotic residues are still discharged into the environment. Further research needs to be undertaken to improve sewage treatment technologies, thereby producing a better quality treated sewage effluent.

Rapid Detection of Selected Steroid Hormones from Sewage Effluents using an ELISA in the Kuils River Water Catchment Area, South Africa

Abstract Steroid hormones are naturally synthesized by both humans and animals and are released into the environment. Significant levels of steroid hormones have been detected in sewage effluent around the world. The potential problem is that these hormones may interfere with the normal function of the endocrine systems, thus affecting reproduction and development in wildlife. Due to the major shortage of water in Western Cape, South Africa there is a great need to recycle water by either direct or indirect methods. The treated sewage effluent‐natural surface water mixture found in the Kuils and Eerste Rivers is used directly for irrigation of agricultural areas. Sewage effluents were collected from four sites (Jonkershoek, Belville, Zandvliet, and Macassar) and subjected to C18 solid phase extraction. Commercially available rapid ELISA kits were validated for the quantification of estrogens in these sewage effluent samples. Analysis of estrone, estradiol, and estriol levels showed a significant difference between the control site (Jonkershoek) and sewage effluent from the three sewage treatment works. Steroid hormone concentrations detected in these sewage effluents were similar to reports from Brittan, Italy, Germany, Canada, and Netherlands.

Ecotoxicity of silver nanomaterials in the aquatic environment: A review of literature and gaps in nano-toxicological research

There has been extensive growth in nanoscale technology in the last few decades to such a degree that nanomaterials (NMs) have become a constituent in a wide range of commercial and domestic products. With NMs already in use in several consumer products, concerns have emerged regarding their potential adverse environmental impacts. Although research has been undertaken in order to minimise the gaps in our understanding of NMs in the environment, little is known about their bioavailability and toxicity in the aquatic environment. Nano-toxicology is defined as the study of the toxicity of nanomaterials. Nano-toxicology studies remain poorly and unevenly distributed. To date most of the research undertaken has been restricted to a narrow range of test species such as daphnids. Crabs are bio-indicators that can be used for toxicological research on NMs since they occupy a significant position in the aquatic food chain. In addition, they are often used in conventional ecotoxicological studies due to their high sensitivity to environmental stressors and are abundantly available. Because they are benthic organisms they are prone to contaminant uptake and bioaccumulation. To our knowledge the crab has never been used in nano-toxicological studies. In this context, an extensive review on published scientific literature on the ecotoxicity of silver NPs (AgNPs) on aquatic organisms was conducted. Some of the most common biomarkers used in ecotoxicological studies are described. Emphasis is placed on the use of biomarker responses in crabs as monitoring tools, as well as on its limitations. Additionally, the gaps in nano-toxicological research and recommendations for future research initiatives are addressed.

THE IN VITRO EFFECTS OF ROOIBOS AND BLACK TEA ON IMMUNE PATHWAYS

The in vitro effects of Aspalathus linearis (Rooibos tea) and Camellia sinensis (Black tea) on biomarkers of specific immune pathways were determined using whole blood culture assays. Stimulated and unstimulated whole blood cultures were incubated with tea extracts. Enzyme linked immunosorbent assays were used to screen spent culture medium for Interleukin-6, Interleukin-10 and Interferon gamma as biomarkers for inflammation, humoral immunity, and cell mediated immunity, respectively. Rooibos and Black tea addition to unstimulated whole blood cultures induced higher Interleukin-6, Interleukin-10, and Interferon gamma secretion. Addition of Rooibos tea to stimulated whole blood cultures induced higher Interleukin-6, lower Interleukin-10, and had no effect on Interferon gamma secretion. Black tea addition to stimulated whole blood cultures inhibited Interleukin-6, Interleukin-10, and Interferon gamma production. The data indicates that Rooibos and Black tea modulates immune function in vitro.

The implementation of a battery of in vivo and in vitro bioassays to assess river water for estrogenic endocrine disrupting chemicals

Previous research has shown that accurate evaluation of environmental water samples for estrogenic activity requires a panel of in vitro and in vivo bioassays, which are based on different molecular and cellular action mechanisms. In the current study, a test battery containing four assays was used to analyze water from the Eerste River, South Africa for estrogenicity. Three sites were used for analysis, namely Jonkershoek (control site situated in the mountains at the origin of the Eerste River), sewage effluent from Stellenbosch sewage treatment works and Spier site (sampling site on the Eerste River downstream from Stellenbosch). Estrogenicity was determined using an estrone enzyme linked immuno sorbent assay (ELISA), estrogen induced proliferation of human breast cancer adenocarcinoma cells (MCF-7) also known as the E-SCREEN, estrogen induced suppression of estrogen receptor alpha protein expression (ER-α) in MCF-7 cells (ERα assay) and by monitoring estrogen induced vitellogenin (VTG) synthesis in juvenile Oreochromis mossambicus (VTG assay). Low concentrations of estrone (ranging between 1.4 and 2.2 ng/l) near the detection limit of the assay were detected in samples collected from Jonkershoek. Water from this site shows no estrogenicity in the E-SCREEN, ERα assay or VTG synthesis bioassay. The estrone concentrations in the sewage effluent extracts, as well as Spier site extracts, ranged between 14.7 and 19.4 ng/l. The assays using ERα induction by the MCF-7 cell line, MCF-7 proliferation and in vivo VTG synthesis by juvenile tilapia showed that these samples are estrogenic. The results obtained for the assays in the battery are comparable.

Effect of temperature on oxidative stress parameters and enzyme activity in tissues of Cape River crab (Potamanautes perlatus) following exposure to silver nanoparticles (AgNP)

ABSTRACT Biomarkers of oxidative stress have been widely used in environmental assessments to evaluate the effects of exposure of aquatic organisms to contaminants from various anthropogenic sources. Silver nanoparticles (AgNP), the most produced NP worldwide and used in several consumer products, are known to produce oxidative stress in aquatic organisms. Similarly, temperature is also known to affect reactive oxygen species (ROS) by influencing the inputs of contaminants into the environment, as well as altering behavior, fate, and transport. Aquatic ecosystems are affected by both anthropogenic releases of contaminants and increased temperature. To test this hypothesis, the influence of AgNP and temperature in the response to multiple biomarkers of oxidative stress was studied in the gills and hepatopancreas of the Cape River crab Potamonautes perlatus. Responses were assessed through activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and the nonenzymatic antioxidant glutathione S-transferase (GST). The response of the oxidative stress biomarkers analyzed was always higher in hepatopancreas than in gills. Elevated temperatures (28°C) induced oxidative stress by increasing SOD, CAT, and GST activities, particularly at 100 µg/ml AgNP. These data indicate that AgNP-mediated toxicity to P. perlatus is modulated by elevated temperatures, but this relationship is not linear. Co-effects of AgNP and temperature are reported for the first time in P. perlatus.

THE IN VITRO EFFECTS OF ARTIFICIAL AND NATURAL SWEETENERS ON THE IMMUNE SYSTEM USING WHOLE BLOOD CULTURE ASSAYS

This article investigates the effects of commercially available artificial (aspartame, saccharin, sucralose) and natural sweeteners (brown sugar, white sugar, molasses) on the immune system. Human whole blood cultures were incubated with various sweeteners and stimulated in vitro with either phytohemagglutinin or endotoxin. Harvested supernatants were screened for cytotoxicity and cytokine release. Results showed that none of the artificial or natural sweeteners proved to be cytotoxic, indicating that no cell death was induced in vitro. The natural sweetener, sugar cane molasses (10 ug/mL), enhanced levels of the inflammatory biomarker IL-6 while all artificial sweeteners (10 ug/mL) revealed a suppressive effect on IL-6 secretion (P < 0.001). Exposure of blood cells to sucralose-containing sweeteners under stimulatory conditions reduced levels of the biomarker of humoral immunity, Interleukin-10 (P < 0.001). The cumulative suppression of Interleukin-6 and Interleukin-10 levels induced by sucralose may contribute to the inability in mounting an effective humoral response when posed with an exogenous threat.

The effect of Tulbaghia violacea extracts on testosterone secretion by testicular cell cultures.

AIM OF THE STUDY This study aimed to determine the effect of Tulbaghia violacea Harv. on the male reproductive system in vitro by using testicular cell cultures. Tulbaghia violacea is a plant species indigenous to southern Africa and is used locally as a herbal remedy/medicine to treat several ailments. MATERIALS AND METHODS A 50% ethanol extract of Tulbaghia violacea was prepared. Three-month old male Balb/C mice were sacrificed and testicular cell cultures were prepared. Cells were then treated with varying concentrations of the Tulbaghia violacea ethanol extract (with/without Luteinizing hormone (LH)-treatment) and incubated for 4 h. Hormone production and cell viability were evaluated. RESULTS Treatment of cells with Tulbaghia violacea (312.5-5000 μg ml(-1)) significantly increased (P<0.05) LH-induced testosterone production as compared to vehicle-treated control (DMSO) whereas cells without LH-treatment showed no significant change in testosterone concentrations. No significant effect on cell viability was observed at all concentrations tested. CONCLUSIONS The data presented shows that Tulbaghia violacea has androgenic properties. Further studies are warranted to determine and clarify the exact mechanisms involved.

THE EFFECTS OF SACCHARUM OFFICINARIUM (SUGAR CANE) MOLASSES ON CYTOKINE SECRETION BY HUMAN BLOOD CULTURES

This study investigated the effects of sugar cane molasses on the immune system, using cytokines as biomarkers. Whole blood cultures, stimulated in vitro with endotoxin or PHA, were incubated with various concentrations of molasses. No cell death occurred in whole blood cultures incubated with molasses samples. The addition of molasses (800 μg/mL) to unstimulated whole blood cultures resulted in increased levels of the biomarker of inflammation, Interleukin-6 (P < 0.001) and also the biomarker of humoral immunity, Interleukin-10 (P < 0.001). Molasses addition (800 μg/mL) to unstimulated whole blood cultures has no effect on the cell mediated immunity biomarker, Interferon gamma secretion. Molasses has no effect on Interleukin-6, Interleukin-10 and Interferon gamma secretion in stimulated whole blood cultures. Immunostimulation by molasses requires further investigation as it may have potential health impacts.

Development of a bio-assay for estrogens using estrogen receptor alpha gene expression by MCF7 cells as biomarker.

Abstract Estrogenic endocrine disruptors (EDCs) have been identified in soil, food, air, and water, and may produce adverse health effects in both humans and wildlife. Various in vitro assays, including the E-screen that measures estrogen dependent proliferation of the MCF-7 human breast cancer cell line, have been developed and implemented to screen for environmental estrogenic EDCs. This study describes a new amendment to the well known E-screen. A direct ELISA to quantify ERα protein levels on MCF-7 cells cultured in a high through put 96-well format were validated as a biomarker for estrogenicity. The ELISA shows that there is an inverse correlation between ERα levels and 17β-estradiol (E2) concentration (R2 = 1). The detection range of the assay is between 1 and 1000 nM for E2. Results obtained with the ERα ELISA showed a good inverse correlation with total cellular LDH levels that is conventionally used to quantify MCF-7 cell proliferation. This ELISA was employed to assess environmental water extracts for estrogenicity.