The current preference for the immuno-analytical ELISA method for quantitation of steroid hormones (endocrine disruptor compounds) in wastewater in South Africa

Abstract

The availability of national test centers to offer a routine service for analysis and quantitation of some selected steroid hormones [natural estrogens (17-β-estradiol, E2; estrone, E1; estriol, E3), synthetic estrogen (17-α-ethinylestradiol, EE2), androgen (testosterone), and progestogen (progesterone)] in wastewater matrix was investigated; corresponding internationally used chemical- and immuno-analytical test methods were reviewed. The enzyme-linked immunosorbent assay (ELISA) (immuno-analytical technique) was also assessed for its suitability as a routine test method to quantitate the levels of these hormones at a sewage/wastewater treatment plant (WTP) (Darvill, Pietermaritzburg, South Africa), over a 2-year period. The method performance and other relevant characteristics of the immuno-analytical ELISA method were compared to the conventional chemical-analytical methodology, like gas/liquid chromatography-mass spectrometry (GC/LC-MS), and GC-LC/tandem mass spectrometry (MSMS), for quantitation of the steroid hormones in wastewater and environmental waters. The national immuno-analytical ELISA technique was found to be sensitive (LOQ 5 ng/L, LOD 0.2-5 ng/L), accurate (mean recovery 96%), precise (RSD 7-10%), and cost-effective for screening and quantitation of these steroid hormones in wastewater and environmental water matrix. A survey of the most current international literature indicates a fairly equal use of the LC-MS/MS, GC-MS/MS (chemical-analytical), and ELISA (immuno-analytical) test methods for screening and quantitation of the target steroid hormones in both water and wastewater matrix. Internationally, the observed sensitivity, based on LOQ (ng/L), for the steroid estrogens E1, E2, EE2, is, in decreasing order: LC-MSMS (0.08-9.54) > GC-MS (1) > ELISA (5) (chemical-analytical > immuno-analytical). At the national level, the routine, unoptimized chemical-analytical LC-MSMS method was found to lack the required sensitivity for meeting environmental requirements for steroid hormone quantitation. Further optimization of the sensitivity of the chemical-analytical LC-tandem mass spectrometry methods, especially for wastewater screening, in South Africa is required. Risk assessment studies showed that it was not practical to propose standards or allowable limits for the steroid estrogens E1, E2, EE2, and E3; the use of predicted-no-effect concentration values of the steroid estrogens appears to be appropriate for use in their risk assessment in relation to aquatic organisms. For raw water sources, drinking water, raw and treated wastewater, the use of bioassays, with trigger values, is a useful screening tool option to decide whether further examination of specific endocrine activity may be warranted, or whether concentrations of such activity are of low priority, with respect to health concerns in the human population. The achievement of improved quantitation limits for immuno-analytical methods, like ELISA, used for compound quantitation, and standardization of the method for measuring E2 equivalents (...

Endocrine-Disrupting Compounds: An Overview on Their Occurrence in the Aquatic Environment and Human Exposure

“…For these reasons, alternative immuno-analytical methods for rapid detection of EDCs such as enzyme-linked immunosorbent assay (ELISA) and immunosensors were developed in the last years [107]. The ELISA method was successfully employed for the quantification of nonylphenol (LOD of 6 ng/L [95]), bisphenol A (LOD range 30-80 ng/L [96]), and hormones with good sensitivity (LOD of 0.2-5 ng/L for E2), accuracy (mean recovery 96%), and precision (RSD 7-10) [108]. These immuno-analytical methodologies have high sensitivity, cost effectiveness and simplification but employ bioantibodies that are unstable and require a long time to be prepared [109].…”

Recent Advances in Solid-Phase Extraction (SPE) Based on Molecularly Imprinted Polymers (MIPs) for Analysis of Hormones

“…The increasing concentrations of steroid hormone residues in various matrices in the environment is proof that even with the bans that are currently in place, their increased application is still predominant (Table 1). In general, global studies have shown that these hormones are frequently detected in waste and surface waters [9,29,[32][33][34][36][37][38][39][40][41][42]. The detection of steroid hormones in the environment has been reported to differ from country to country (Table 1).…”

“…In some cases, their concentrations within the same country also differ depending on the regions or provinces. For example, in South Africa, maximum concentrations for estradiol of 7133 ng/L were detected in wastewaters from Gauteng Province [42], while concentrations of up to 2000 ng/L were reported in KwaZulu Natal Province for estrone (E1), 17-βestradiol (E2), estriol (E3), 17-α-ethinylestradiol (17-α-EE2), androgens, and progestogens (PRO) [9]. Olatunji et al [45] reported concentrations ranging from 600 to 45,500 ng/L for E2 and E3 in surface water around animal farms in Western Cape.…”

“…Human and animal excretion often contain natural and exogenous variation of hormones [8]. This is due to the fact that while steroids such as estrogens, mineralocorticoids (aldosterone), glucocorticoids, androgens, and progesterones can be secreted in the adrenal cortex [9], there are still exogenous hormones used as contraceptives [10], medicines [11], and growth promoters [12]. As a result, hormones can end up in the environment via wastewater treatment plant effluent discharge into receiving water bodies [13].…”

Preparation of a monoclonal antibody against testosterone and its use in development of an immunochromatographic assay

“…Before constructing a strip test to meet the limit requirement, a sensitive and highly specific antibody resistant to matrix interference is needed. Many enzyme-linked immunosorbent assay (ELISA) have been developed to measure testosterone levels in plasma, serum, urine and environmental samples at high parts per million levels or even lower (Al-Dujaili, 2006;Feswick et al, 2014;Kim et al, 2015;Lu et al, 2006;Manickum & John, 2015;Nash et al, 2000;Xing, et al, 2014).…”