An LC-MS/MS based survey of contaminants of emerging concern in drinking water in South Africa

Abstract

Advances in many analytical techniques allow the detection of compounds in water at very low concentrations (ng/L), which has facilitated the identification of many compounds in drinking water that went previously undetected. Some of these compounds are contaminants of emerging concern (CECs), which is broadly defined as any chemical or microorganism that is not currently being routinely monitored but has recently been identified as being present in the environment, and that may pose health or ecological risks. CECs can include pharmaceuticals, personal health care products and pesticides. Some CECs can act as endocrine disruptors, interfering with the normal functioning of the human endocrine system, potentially influencing foetal and child development. Although the level of many of these compounds are orders of magnitude below known acute toxicity levels, the health impact of long term exposure at low levels is mostly unknown. In this study, we present the results of a national survey over four seasons of potential CECs in the drinking water of major South African cities. The contaminants most often detected were the related herbicides atrazine and terbuthylazine, and the anticonvulsant and mood-stabilising drug, carbamazepine. The levels of these CECs were well below maximum levels proposed by the World Health Organization and the US Environmental Protection Agency. However, the range of CECs detected in drinking water, and seasonal and geographic variability in CECs levels, warrant a more frequent screening programme.

Agrochemicals in freshwater systems and their potential as endocrine disrupting chemicals: A South African context

“…A well-known class of pesticides currently used in South Africa are triazine herbicides. They are used to control weeds in both agricultural and non-agricultural applications ( Kunene and Mahlambi, 2020 ) and include atrazine, simazine, prometryn, propazine, terbuthylazine, ametryn, prometon, terbutryn and atraton ( Quinn et al , 2011 ; Odendaal et al , 2015 ) ( Table 1 ). Atrazine (2-chloro-4-ethylamino-6-isopropyl-amino-s-triazine) is probably the best-known herbicide in the triazine class and is widely used in both pre- and early post-emergent applications ( World Health Organization, 2011 ) for the control of broadleaf and grassy weeds ( Gore et al , 2015 ; Asouzu Johnson et al , 2019 ).…”

“…Although triazine herbicides in drinking water have been detected at different South African localities, the concentrations differ. Higher atrazine levels were recorded in drinking water from Johannesburg throughout the year and Bloemfontein in autumn and spring (13 to 185 ng/L), when compared with Cape Town, Port Elizabeth, Durban, and Pietermaritzburg (not detected to 23 ng/L) ( Odendaal et al , 2015 ). The highest level of atrazine detected in river and tap water from the Vals and Renoster catchments ( Machete and Shadung, 2019 ) was more than twice (350 ng/L) the concentration reported by Odendaal et al (2015) .…”

“…Higher atrazine levels were recorded in drinking water from Johannesburg throughout the year and Bloemfontein in autumn and spring (13 to 185 ng/L), when compared with Cape Town, Port Elizabeth, Durban, and Pietermaritzburg (not detected to 23 ng/L) ( Odendaal et al , 2015 ). The highest level of atrazine detected in river and tap water from the Vals and Renoster catchments ( Machete and Shadung, 2019 ) was more than twice (350 ng/L) the concentration reported by Odendaal et al (2015) . However, in both studies, the levels were still below the atrazine drinking water guideline values proposed by the World Health Organization (WHO) (100 μg/L) ( World Health Organization, 2011 ).…”

“…Although many studies quantified agrochemicals in South African water ( Amdany et al , 2014 ; Odendaal et al , 2015 ; Wooding et al , 2017 ; Adeyinka et al , 2019 ; Ojemaye et al , 2020 ), few studies have also investigated the associated ED effects ( Barnhoorn et al , 2010 ; Arukwe et al , 2016 ). Most studies that evaluated ED of agrochemicals in South Africa were laboratory-based using in vitro or in vivo bioassays of single active ingredients or pesticide mixtures ( Archer and Van Wyk, 2015 ; Rimayi et al , 2018b ).…”

Sex‐dependent thermal history influences cold tolerance, longevity and fecundity in false codling moth Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

“…The pest problem was exacerbated when T. leucotreta developed resistance to several insecticides, as well as stricter regulations that were imposed on the use of pesticides by exporters (Hofmeyr & Pringle, ). The use of potentially harmful pesticides that are increasingly detected in ground‐water in South Africa raises concerns for long‐term human health and safety (Odendaal et al ., ). An integrated sustainable approach to pest management of this species became critical and resulted in the initiation of a collaborative, multi‐institutional sterile insect technique (SIT) research project during 2002 to control T. leucotreta as part of an area‐wide pest control programme (Hofmeyr et al ., ).…”