Browsing by Author "Newman, Brent K"
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Item A review of metal pollution in a transformed, urban South African Estuary(2024-12) Ndhlovu, A; Adams, JB; Nel, M; Newman, Brent K; Rishworth, GM; Human, LRDMetal pollutants enter coastal water bodies from agricultural, industrial, and domestic wastewater activities amongst other sources. These pollutants are often transported through the food chain to higher trophic levels including organisms such as fish. Ultimately, they may pass to humans that consume contaminated seafoods. As such, it is imperative to understand how metals in estuarine systems are transported across trophic levels. Baseline data on metal concentrations are of crucial importance to evaluate changes over time and amongst areas to inform management and conservation strategies. In this assessment, we compile and discuss a database of metal concentrations recorded in various environmental media in the Swartkops River estuary, as a baseline against which future comparisons can be made. The Swartkops Estuary is subjected to considerable anthropogenic pressure that has led to a deterioration in water quality. We also provide a conceptual model to understand the flow of metals in the estuary. We furthermore identify lines of future research that will address gaps and uncertainties in the existing data and provide recommendations for remediation. Studies on metal concentrations in the water column of the estuary are limited. Studies on metals in sediment suggest that the estuary is not significantly metal contaminated. While studies revealed that plants do accumulate metals and fauna studies show differences in metal concentrations in the tissue of invertebrates and fish. It is difficult to conclude if these fauna are accumulating metals in their tissue compared to historically and if concentrations reflect uptake as a consequence of exposure to metal contaminated water, sediment and food.Item AQUA-GAPS/MONET-derived concentrations and trends of PAHs and polycyclic musks across global waters(2024-07) Lohmann, R; Vrana, B; Muir, D; Smedes, F; Sobotka, J; Zeng, EY; Bao, LJ; Allan, IJ; Astrahan, P; Newman, Brent KPolycyclic aromatic hydrocarbons (PAHs), released from petrogenic, pyrogenic or diagenetic sources (degradation of wood materials), are of global concern due to their adverse effects, and potential for long-range transport. While dissolved PAHs have been frequently reported in the literature, there has been no consistent approach of sampling across water bodies. Passive samplers from the AQUA/GAPS-MONET initiative were deployed at 46 sites (28 marine and 18 freshwater), and analyzed for 28 PAHs and six polycyclic musks (PCMs) centrally. Freely dissolved PAH concentrations were dominated by phenanthrene (mean concentration 1500 pg L–1; median 530 pg L–1) and other low molecular weight compounds. Greatest concentrations of phenanthrene, fluoranthene, and pyrene were typically from the same sites, mostly in Europe and North America. Of the PCMs, only galaxolide (72% of samples) and tonalide (61%) were regularly detected, and were significantly cross-correlated. Benchmarking of PAHs relative to penta- and hexachlorobenzene confirmed that the most remote sites (Arctic, Antarctic, and mountain lakes) displayed below average PAH concentrations. Concentrations of 11 of 28 PAHs, galaxolide and tonalide were positively correlated (P < 0.05) with population density within a radius of 5 km of the sampling site. Characteristic PAH ratios gave conflicting results, likely reflecting multiple PAH sources and postemission changes.Item Biological toxicity estimates show involvement of a wider range of toxic compounds in sediments from Durban, South Africa than indicated from instrumental analyses(Elsevier, 2019-01) Vogt, T; Pieters, R; Giesy, J; Newman, Brent KThe toxic equivalences (TEQs) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from sediment of aquatic systems in Durban, South Africa were determined in two ways: 1) TEQs of PAHs and PCBs were determined by instrumental analyses and converted to 2,3,7,8-tetrachlorodibenzo-para-dioxin equivalence (TCDDeq). 2) Bioassay equivalences (BEQs) of aryl hydrocarbon receptor (AhR) ligands were analysed using the H4IIE-luc bioassay. TEQs of PCBs ranged from below limit of detection (Item Brominated flame-retardants in Sub-Saharan Africa: burdens in inland and coastal sediments in the eThekwini Metropolitan Municipality, South Africa(American Chemical Society, 2013-09) La Guardia, MJ; Hale, RC; Newman, Brent KBrominated flame-retardant (BFR) additives are present in many polymeric consumer products at percent levels. High environmental concentrations have been observed near cities and polymer, textile and electronics manufacturing centers. Most studies have focused on European, North American and Asian locales. Releases are likely rising most dramatically in countries with weak environmental and human health regulation and enforcement, demand for electrical and electronic equipment (EEE) is escalating, and importation of waste EEE occurs. Several African countries meet these criteria, but little data are available on burdens or sources. To better understand the extent of BFR environmental dissemination in a southern African urban community, inland and coastal sediments were collected in the eThekwini metropolitan municipality, South Africa, and analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), 2-ethylhexyl 2,3,4,5-tretabromophalate (TBPH), 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE) and decabromodiphenyl ethane (DBDPE). BFRs were detected in all samples (n=45). Concentration data are presented on total organic carbon (TOC) normalized basis. SBFR ranged from 114 to 47,100 ng g(sup-1). Decabromodiphenyl ether was detected in 93% of samples (mean concentration 3208 ng g(sup-1) followed by TBB at 91% (mean conc. 545 ng g-1). Durban Bay is strongly influenced by urban runoff and tidal hydrology and sediments therein exhibited SPBDE concentrations ranging from 1850 to 25,400 ng g(sup-1) (median conc. 3240 ng g(sup-1). These levels rival those in the heavily impacted Pearl River Delta, China. BFRs likely enter the South African environment during manufacture of BFR-containing products, during and following product use (i.e. after disposal and as a result of materials recycling activities), and from nonpoint sources such as atmospheric fallout and urban runoff. These results underline the need to investigate further the environmental burdens and risks associated with BFRs in developing countries.Item Global occurrence of anti-infectives in contaminated surface waters: Impact of income inequality between countries(Elsevier, 2015-07) Segura, PE; Takada, H; Correa, JA; Saadi, KE; Koike, T; Onwona-Agyeman, S; Ofosu-Anim, J; Sabi, EB; Wasonga, OV; Mghalu, JM; Dos Santos Junior, AM; Newman, Brent K; Weerts, Steven P; Yargeau, VThe presence anti-infectives in environmental waters is of interest because of their potential role in the dissemination of anti-infective resistance in bacteria and other harmful effects on non-target species such as algae and shellfish. Since no information on global trends regarding the contamination caused by these bioactive substances is yet available, we decided to investigate the impact of income inequality between countries on the occurrence of anti-infectives in surface waters. In order to perform such study, we gathered concentration values reported in the peer-reviewed literature between 1998 and 2014 and built a database. To fill the gap of knowledge on occurrence of anti-infectives in African countries, we also collected 61 surface water samples from Ghana, Kenya, Mozambique and South Africa, and measured concentrations of 19 anti-infectives. A mixed one-way analysis of covariance (ANCOVA) model, followed by Turkey-Kramer post hoc tests was used to identify potential differences in anti-infective occurrence between countries grouped by income level (high, upper-middle and lower-middle and low income) according to the classification by the World Bank. Comparison of occurrence of anti-infectives according to income level revealed that concentrations of these substances in contaminated surface waters were significantly higher in low and lower-middle income countries (p=0.0001) but not in upper-middle income countries (p=0.0515) compared to high-income countries. We explained these results as the consequence of the absence of or limited sewage treatment performed in lower income countries. Furthermore, comparison of concentrations of low cost anti-infectives (sulfonamides and trimethoprim) and the more expensive macrolides between income groups suggest that the cost of these substances may have an impact on their environmental occurrence in lower income countries. Since wastewaters are the most important source of contamination of anti-infectives and other contaminants of emerging concern in the environment, it is expected that deleterious effects to the aquatic biota caused by these substances will be more pronounced in countries with inadequate wastewater and collection infrastructure. With the information currently available, we could not evaluate either the role of the receiving environment or the importance of regulatory frameworks on the occurrence of anti-infectives in surface waters. Future studies should focus on these two factors in order to better evaluate risks to aquatic ecosystems in LM&LICs. We propose that CECs such as anti-infectives could be used as a new class of environmental degradation indicators that could be helpful to assess the state of development of wastewater collection and treatment infrastructure around the world.Item In vitro screening for endocrine disruptive activity in selected South African harbours and river mouths(National Inquiry Services Centre (NISC), 2015-12) Truter, JC; Van Wyk, JH; Newman, Brent KVarious waterborne anthropogenic contaminants disrupt the endocrine systems of wildlife and humans, targeting reproductive pathways, among others. Very little is known, however, regarding the occurrence of endocrine disruptive activity in South African freshwater ecosystems, and coastal ecosystems have not been studied in this regard. In a first attempt to investigate endocrine disruptive activity in South African coastal waters, surface water samples collected from harbours, river mouths and estuaries in three metropolitan municipalities, eThekwini (which includes Durban), Nelson Mandela (specifically Port Elizabeth Harbour) and City of Cape Town, were screened for (anti) oestrogenicity and (anti)androgenicity using recombinant yeast bioassays. Moreover, levels of the female hormone 17ß-(o)estradiol (E2) were determined in all samples, as well as a selection of hydrocarbons in the eThekwini samples. A high proportion of samples collected from eThekwini were oestrogenic, whereas none from Port Elizabeth Harbour and only a single river mouth sampled in the City of Cape Town were oestrogenic. E2 was detected in all the samples tested, but at higher concentrations at the eThekwini and City of Cape Town localities than Port Elizabeth Harbour. In addition, the recombinant yeast assays revealed that anti-androgenicity was widespread, being detected in the majority of samples screened apart from those representing Port Elizabeth Harbour. Conversely, no anti-oestrogenic or androgenic activity was detected. Anti-androgenicity did not associate with hydrocarbon loads, providing evidence that other anti-androgens were responsible for the observed activity. The present data suggest potential reproductive disruption in marine and estuarine fauna inhabiting the eThekwini and City of Cape Town regions.Item Latitudinal gradients and poleward expansion of mangrove ecosystems in South Africa: 50 years after Macnae’s first assessment(NICIS and Taylor and Francis, 2018-07) Peer, N; Rajkaran, A; Miranda, NAF; Taylor, RH; Newman, Brent K; Porri, F; Raw, JL; Mbense, SP; Adams, JB; Perissinotto, RMangroves occur in South African estuaries at their poleward distribution limits, extending into temperate habitats. In 1963, William Macnae published the first comprehensive assessment of mangrove swamps in South Africa and made firsthand observations of these mangrove ecosystems. This article reassesses South African mangrove habitats, highlighting changes since Macnae’s assessment, through a literature review of research done in the past 50 years and using the results of a dedicated mangrove survey spanning 2012–2017. Until now, changes have been recorded mostly for mangrove vegetation, including a change in mangrove cover and a poleward shift of mangrove species. While some mangrove-associated fauna have disappeared from most sites (e.g. the gastropod Terebralia palustris), others, such as fiddler crabs, have spread farther south. The effects of decreasing diversity with an increase in latitude were not observed along the South African coast. Instead, habitat quality and estuarine mouth state seem to exert greater influence on species diversity in the mangroves, and a poleward shift in species distribution is now evident not just for the mangrove flora but for the fauna as well. South African mangrove research needs to include a continuous monitoring plan, especially if we are to contribute to global knowledge on blue carbon, the effects of sea-level rise, and the resilience of the mangrove ecosystem.Item Marine outfalls monitoring at the CSIR: Evaluating the impact of wastewater discharge on our marine environment(2012-10) Arabi, Sumaiya; Newman, Brent K; Weerts, Steven PThe impact of wastewater discharge on the marine environment requires careful monitoring. The CSIR’s Marine Outfalls Monitoring Programme has a history of 45 years, and continues to build capacity in the field of marine pollution research and management.Item Occurrence and potential hazard of pharmaceutically active compounds in coastal waters in Cape Town(2024) Newman, Brent K; Velayudan, Anisha; Oelofse, Gregg; Colenbrander, Darryl; Petrović, Mira; Álvarez-Muñoz, Diana; Čelić, Mira; Le Roux, Maria; Ndungu, Kria; Madikizela, Lawrence M; Chimuka, Luke; Richards, HeidiThis presentation provides details on investigations into the prevalence, concentrations, and potential ecological impacts of pharmaceutically active compounds in coastal waters in Cape Town.Item Occurrence and potential hazard posed by pharmaceutically active compounds in coastal waters in Cape Town, South Africa(2024-11) Newman, Brent K; Velayudan, Anisha; Petrović, M; Álvarez-Muñoz, D; Čelić, M; Oelofse, G; Colenbrander, D; Le Roux, M; Ndungu, K; Madikizela, LMThe occurrence of 58 pharmaceutically active compounds (PhACs) in surface water at 28 coastal and five river sites, and in two stormwater flows in Cape Town, South Africa, was investigated in winter and summer. After accounting for quality assurance and control data, 33 PhACs were considered in detail. In winter, 25 PhACs were found at one or more sites and 27 in summer. Salicylic acid was the most widespread PhAC in each season. At least one PhAC was found at each site in each survey. The largest number found at a site was 22 at Lifebox23 Beach in winter and 23 at Macassar Beach and in the Black and Diep Rivers in summer. These sites are strongly directly or indirectly affected by wastewater treatment plant discharges. The range in ΣPhAC concentrations was 41 ng L−1 to 9.3 μg L−1 in winter and 109 ng L−1 to 18.9 μg L−1 in summer. The hazard posed by PhACs was estimated using Predicted No Effect Concentrations (PNEC) from several sources. Hazard Quotients (HQs) for numerous PhACs were >1, and for several even >10, including azithromycin, cimetidine, clarithromycin, erythromycin, and ibuprofen. The highest hazards were at coastal sites strongly indirectly affected by wastewater treatment plant discharges. Azithromycin, trimethoprim, and sulfamethoxazole at some sites may have promoted antibiotic resistance in bacteria, while irbesartan at some sites might have posed a hazard to fish according to the fish plasma model. The concentrations of several PhACs at some coastal sites are higher than concentrations reported in estuarine, coastal, and marine waters in other parts of the world.Item Occurrence, spatial distribution, and source apportionment of microplastics in Durban Bay, South Africa(2024-07) Latcheman, DDS; Richards, H; Madikizela, LM; Ndungu, K,; Newman, Brent K; Chimuka, LGlobally, microplastics have been identified in a diverse range of environments. However, the extent of microplastic pollution in South Africa’s context is largely lacking. In this study, an investigation of microplastic pollution was conducted across the Durban Bay harbour located in the province of KwaZulu-Natal, South Africa. Microplastic evaluation was performed both on surface water and sediment samples, collected from various spots across the harbour. Microplastics were extracted and analysed for their characteristics using visual identification on stereomicroscopes, and chemical characterisation using Raman-microscopy. Microplastics were detected in all samples, with abundances of up to 80.72 MP m−3 in surface water samples, and 1.76 MP g−1 in sediments. Fibres and fragments were the most observed morphologies in both surface water and sediment samples. In this case, the detected fibres comprised up to 75.68% in surface waters, and 45.54% in sediments, while fragments reached 19.84% in surface waters, and 41.07% in sediment samples. Polyethylene, polypropylene, and polyester were the most dominant polymers observed in the investigated samples. In general, higher microplastic abundances were found in the study sites located near the river inflows and stormwater drains, with anthropogenic activities such as shipping bays. Overall, the microplastic abundance in Durban Bay was comparable with the levels found in other studies within South Africa and across the globe.Item PAHs, OCPs and PCBs in sediments from three catchments in Durban, South Africa(NATL INQUIRY SERVICES CENTRE PTY LTD, 2018-04) Vogt, T; Pieters, R; Newman, Brent KPolycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were analysed from sediment samples collected in 2012 from rivers, surface runoff canals and estuaries in three highly urbanised catchments in durban, KwaZulu-Natal, South Africa. PAHs were ubiquitous, at concentrations between 36–6 800 ng g-1 dry mass (dm). Congener ratio diagnosis suggests the PAHs were derived predominantly from pyrogenic sources. Four OCPs and/or their metabolites were detected at varying frequencies and concentrations. Of these, dichlorodiphenyltrichloroethane (ddT) and metabolites were most frequently detected and were at a high concentration in sediment in some systems. Toxaphene was detected at a high concentration at some sites. The total PCB concentration varied widely, from below the method detection limit to 110 ng g-1 (dm). Based on the comparison of chemical concentrations to international sediment quality guidelines, PAH, OCP and PCB concentrations in most sediment samples posed a low risk to sediment-dwelling organisms. However, in some instances the risk was moderate or high. It is recommended that these compounds be monitored more frequently and comprehensively in aquatic ecosystems to better understand the ecological and human health implications.Item Passive-Sampler-Derived PCB and OCP concentrations in the waters of the world - First results from the AQUA-GAPS/MONET Network(2023-06) Lohmann, R; Vrana, B; Muir, D; Smedes, F; Sobotka, J; Zeng, EY; Bao, L-J; Allan, IJ; Astrahan, P; Newman, Brent KPersistent organic pollutants (POPs) are recognized as pollutants of global concern, but so far, information on the trends of legacy POPs in the waters of the world has been missing due to logistical, analytical, and financial reasons. Passive samplers have emerged as an attractive alternative to active water sampling methods as they accumulate POPs, represent time-weighted average concentrations, and can easily be shipped and deployed. As part of the AQUA-GAPS/MONET, passive samplers were deployed at 40 globally distributed sites between 2016 and 2020, for a total of 21 freshwater and 40 marine deployments. Results from silicone passive samplers showed a-hexachlorocyclohexane (HCH) and -HCH displaying the greatest concentrations in the northern latitudes/Arctic Ocean, in stark contrast to the more persistent penta (PeCB)- and hexachlorobenzene (HCB), which approached equilibrium across sampling sites. Geospatial patterns of polychlorinated biphenyl (PCB) aqueous concentrations closely matched original estimates of production and use, implying limited global transport. Positive correlations between log-transformed concentrations of S7PCB, SDDTs, Sendosulfan, and Schlordane, but not SHCH, and the log of population density (p < 0.05) within 5 and 10 km of the sampling sites also supported limited transport from used sites. These results help to understand the extent of global distribution, and eventually time-trends, of organic pollutants in aquatic systems, such as across freshwaters and oceans. Future deployments will aim to establish time-trends at selected sites while adding to the geographical coverage.Item A strategic framework for coastal and marine water quality management in the Western Indian Ocean(2022-12) Taljaard, Susan; Weerts, Steven P; Arabi, Sumaiya; Newman, Brent K; Bosire, JGovernments in the Western Indian Ocean (WIO) region, through a consultative process, have agreed on the need for a suite of national and regional actions to address major stresses on the marine environment. This is demonstrated in several initiatives, including: The Protocol for the Protection of the Marine and Coastal Environment of the Western Indian Ocean from Land-Based Sources and Activities (LBSA Protocol) to the Nairobi Convention .Implementation of the Strategic Action Programme for the protection of the Western Indian Ocean from land-based sources and activities (WIOSAP) .The Western Indian Ocean Large Marine Ecosystems Strategic Action Programme Policy Harmonisation and Institutional Reforms (WIO LME SAPPHIRE) .Enforcing Environmental Treaties in African, Caribbean and Pacific (ACP) Countries (ACP-MEA Phase III) - funded by the European Union. For coastal and marine water quality management (C&MWQM), improved capacity and the implementation of strategic frameworks can improve ecosystem integrity with consequent socio-economic and environmental benefits, locally, regionally and globally. Countries in the WIO region vary in their current planning and implementation in C&MWQM, and the development of a regional strategic framework will provide a basis for adoption and integration into national frameworks. This paper presents a strategic framework for C&MWQM to be considered for implementation in the region. Ultimately, achieving the strategic objective for coastal and marine water quality in the WIO region, which states `Water quality in the WIO region meets international standards by the year 2035,' depends on the success of the framework and on adopting the proposed implementation thereof into national policy and best practice. It also requires political commitment to assist in securing dedicated financial resources and the skilled personnel required to execute C&MWQM programmes.Item Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments(Frontiers Media, 2015-08) Suzuki, S; Ogo, M; Koike, T; Takada, H; Newman, Brent KAntibiotic resistant bacteria are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs) into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3, and tet(M), in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP) in South Africa. There was no correlation between antibiotic concentrations and ARGs, suggesting the targeted ARGs are spread in a wide area without connection to selection pressure. Among sul genes, sul1 and sul2 were major genes in the total (over 10-2 copies/16S) and colony forming bacteria assemblages (~10-1 copies/16S). In urban waters, the sul3 gene was mostly not detectable in total and culturable assemblages, suggesting sul3 is not abundant. tet(M) was found in natural assemblages with 10-3 copies/16S level in STP, but was not detected in colony forming bacteria, suggesting the non-culturable (yet-to-be cultured) bacterial community in urban surface waters and STP effluent possess the tet(M) gene. Sulfamethoxazole (SMX) resistant (SMXr) and oxytetracycline (OTC) resistant (OTCr) bacterial communities in urban waters possessed not only sul1 and sul2 but also sul3 and tet(M) genes. These genes are widely distributed in SMXr and OTCr bacteria. In conclusion, urban river and estuarine water and STP effluent in the Durban area were highly contaminated with ARGs, and the yet-to-be cultured bacterial community may act as a non-visible ARG reservoir in certain situations.Item Tri-locus sequence data reject a ‘‘Gondwanan origin hypothesis” for the African/South Pacific crab genus Hymenosoma(Elsevier, 2009-10) Teske, PR; McLay, CL; Sandoval-Castillo, J; Papadopoulos, I; Newman, Brent K; Griffiths, CL; McQuaid, CD; Barker, NP; Borgonie, G; Beheregaray, LBCrabs of the family Hymenosomatidae are common in coastal and shelf regions throughout much of the southern hemisphere. One of the genera in the family, Hymenosoma, is represented in Africa and the South Pacific (Australia and New Zealand). This distribution can be explained either by vicariance (presence of the genus on the Gondwanan supercontinent and divergence following its break-up) or more recent transoceanic dispersal from one region to the other. We tested these hypotheses by reconstructing phylogenetic relationships among the seven presently-accepted species in the genus, as well as examining their placement among other hymenosomatid crabs, using sequence data from two nuclear markers (Adenine Nucleotide Transporter [ANT] exon 2 and 18S rDNA) and three mitochondrial markers (COI, 12S and 16S rDNA). The five southern African representatives of the genus were recovered as a monophyletic lineage, and another southern African species, Neorhynchoplax bovis, was identified as their sister taxon. The two species of Hymenosoma from the South Pacific neither clustered with their African congeners, nor with each other, and should therefore both be placed into different genera. Molecular dating supports a post-Gondwanan origin of the Hymenosomatidae. While long-distance dispersal cannot be ruled out to explain the presence of the family Hymenosomatidae on the former Gondwanan land-masses and beyond, the evolutionary history of the African species of Hymenosoma indicates that a third means of speciation may be important in this group: gradual along-coast dispersal from tropical towards temperate regions, with range expansions into formerly inhospitable habitat during warm climatic phases, followed by adaptation and speciation during subsequent cooler phases