Antimicrobial resistance screening and profiles: a glimpse from the South African perspective.

According to the Centre for Disease Dynamics Economics and Policy, South Africa represents a paradox of antibiotic management similar to other developing countries, with both overuse and underuse (resulting from lack of access) of antibiotics. In addition, wastewater reuse may contribute towards antibiotic resistance through selective pressure that increases resistance in native bacteria and on clinically relevant bacteria, increasing resistance profiles of the common pathogens. Sediments of surface water bodies and wastewater sludge provide a place where antibiotic resistance genes are transferred to other bacteria. Crop irrigation is thought to be a potential source of exposure to antibiotic-resistant bacteria through the transfer from the water or sludge into crops. The objectives of this study were to examine the antibiotic-resistance profiles of Escherishia coli from three agricultural locations in the Western Cape, South Africa. Using a classical microbiology culture approach, the resistance profiles of E. coli species isolated from river water and sediments, farm dams and their sediments and a passive algal wastewater treatment ponds and sediment used for crop irrigation were assessed for resistance to 13 commonly used antibiotics. Randomly selected E. coli isolates from the sediment and water were tested for resistance. 100% of E. coli isolates were resistant to sulphamethoxazole, highlighting its relevance in the South African context. In river water and farm dam samples, only the E. coli isolated from sediment were found to be resistant to fluoroquinolone or fluorifenicol. In the wastewater treatment ponds, the resistance profiles of E. coli isolated from sediments differed from those isolated from effluent, with 90% of the effluent isolates being resistant to ampicillin. Isolates from the sediment were less resistant (40%) to ampicillin, whereas all the isolates from the pond water and sediment samples were resistant to sulphamethoxazole. These results illustrate the importance of developing a better understanding of antibiotic resistance in agriculture and wastewater scenarios to ensure remedial measures take place where the greatest benefit can be realised especially in countries with limited financial and infrastructural resources. Moreover, the potential for passive algal treatment as an effective, feasible alternative for wastewater treatment is highlighted, with comparable resistance profiles and a reducing overall resistance in the sediment samples.

Treated acid mine drainage and stream recovery: Downstream impacts on benthic macroinvertebrate communities in relation to multispecies toxicity bioassays.

The success and long term effectiveness of extensive and expensive engineering solutions to restore streams impacted by Acid Mine Drainage (AMD) is rarely tested. Concentrations of pollutants were measured in water along a longitudinal gradient from a stretch of the Tweelopie stream, South Africa, that receives pH-treated acid mine drainage (AMD) from an abandoned gold mine. The biotoxic effects of treated AMD were determined through macroinvertebrate biotic indices (SASS5) and a battery of toxicity bioassays. These included the L. sativa, A. cepa, D. magna toxicity and Ames mutagenicity tests, as well as an in vitro human liver cancer cell line HepG2. Even though the Tweelopie stream was moderately to severely degraded by multiple anthropogenic stressors, the impact of the treated AMD was masked by the improvement in the system downstream after mixing with the domestic wastewater effluent receiving stream, and subsequent further dilution as a result of the karst springs downstream. The general improvement of the system downstream was clearly shown by the decrease in the ecotoxicity and mutagenicity in relation to the in-stream macroinvertebrates. PCA multivariate analysis successfully displayed associations between the different environmental variables and the decrease in toxicity and subsequent ecosystem improvement downstream. This study indicated that environmental management of AMD remediation should consider long term assessment strategies, including multiple factors, to promote biological ecosystem recovery.

Towards a rapid assessment protocol for identifying pit lakes worthy of restoration.

Before the introduction of reclamation legislation in South Africa, final cut lakes in mining areas were left without any restoration while the final excavation was not back filled. Characteristics of these lacustrine water bodies vary considerably, but they are often linear in shape, large (1-30 ha), deep (2-30 m) and have poorly developed littoral zones. With water tables often near the surface; a variety of vascular hydrophytes can colonize these bodies, thus establishing emerging wetland type ecosystems. These, man-made aquatic structures that are (unintentionally) created potentially offers some realistic and inexpensive mitigation options for some of the negative impacts associated with mining, i.e. these water bodies can become useful by yielding potentially valuable services. However, no method currently exists to compare and rank these water bodies according ecological integrity and the expected monetary value to be derived from them in order to select sites for restoration. To answer this need, we applied an index to determine the ability of these water bodies to provide useful services in their current state. The index was then used to derive estimates of the monetary value of potential services in order to allow comparison with the cost of restoring the water body in question or to compare with other pit lakes. We present a South African case study to illustrate the method. As far as could be established, this is the first attempt towards creating a rapid assessment tool as standardised way of comparing pit lakes that allows for the ranking and identification of those pit lakes worthy of restoration.

Prevalence of enteropathogenic bacteria in treated effluents and receiving water bodies and their potential health risks.

The failure of wastewater treatment plants to produce effluents of a high microbiological quality is a matter of great concern in terms of water resource pollution. A more serious concern is that this water source is used by communities in developing countries for multiple purposes, which include drinking, recreation and agriculture. The current study investigated the prevalence and potential health risks of enteropathogenic bacteria (Salmonella typhimurium, Shigella dysenteriae and Vibrio cholerae) in the treated effluents of three selected South African Wastewater Treatment Works as well as their receiving water bodies. Culture-based and polymerase chain reaction techniques were used to detect and identify the pathogenic bacteria. The conventional methods revealed that of the 272 water samples collected, 236 samples (86.8%) tested presumptively positive for Salmonella spp., 220 samples (80.9%) for Shigella spp. and 253 samples (93.0%) for V. cholerae. Molecular test results indicated that out of the randomly selected presumptive positive samples (145), zero to 60% of samples were positive for S. typhimurium and S. dysenteriae and 20% to 60% for V. cholerae. For the health risk assessment, the daily combined risk of S. typhimurium, S. dysenteriae and V. cholerae infection was above the lowest acceptable risk limit of 10(-4) as estimated by the World Health Organization for drinking water. This study showed that the target treated wastewater effluents and their receiving water bodies could pose a potential health risk to the surrounding communities.

Organochlorine pesticide levels in Clarias gariepinus from polluted freshwater impoundments in South Africa and associated human health risks.

There are increasing concerns regarding the safe human consumption of fish from polluted, freshwater impoundments. The aim of this study was to analyse the muscle tissue of the sharptooth catfish Clarias gariepinus for selected organo-chlorine pesticides (OCPs) and to perform a human health risk assessment using a standard protocol described by the United States Environmental Protection Agency (US EPA). Fish were collected from the polluted Roodeplaat-(RDPD), Rietvlei-(RVD) and Hartbeespoort (HBPD) Dam impoundments located in the north-eastern regions of South Africa. GC-MS analyses showed levels of various OCPs in fish muscle samples from all three impoundments. For fish collected from the RDPD, p,p'-DDE, endosulfan, lindane and ß- and δ-HCH were the most prevalent OCPs detected, while p,p'-DDE and endosulfan were the most predominant in fish from the RVD. Lindane and ß- and δ-HCH were the main OCPs detected in fish from the HBPD. Dieldrin was the only OCP detected at concentrations for which a cancer risk and a hazard index above the acceptable risk levels were estimated. This was the case for fish from both the RDPD and RVD impoundments. No toxic risk was estimated should fish from the HBPD be consumed.

Health risk implications from simultaneous exposure to multiple environmental contaminants.

Water quality has deteriorated in the upper Olifants River system, South Africa, as a result of land use activities which include mining, agriculture and industries. A health risk assessment was conducted from 2009 to 2011 in the catchment to determine the possible risks local communities face from various pollutants such as microbials, heavy metals and oestrogen in the river water and vegetation. Aluminium and manganese accumulated in plants and vanadium and aluminium concentrations found in selective water samples posed significant health risks when consumed. A quantitative microbial risk assessment revealed that the combined risk of infection ranged from 1 to 26 percent with the Norovirus posing the overall greatest health risk. The anticipated disability adjusted life years resulting from drinking untreated water from these sites are in the order of 10,000 times greater than what is considered acceptable. The oestradiol activity, caused by endocrine disrupting compounds in the water, measured above the trigger value of 0.7ngL(-1). Impoverished communities in the area, who partially depend on river water for potable and domestic use, are exposed to immune-compromising metals that increase their probability of infection from waterborne diseases caused by the excess microbial pathogens in the contaminated surface water.

An ecotoxicological screening tool to prioritise acid mine drainage impacted streams for future restoration.

Streams impacted by acid mine drainage (AMD) typically present water exhibiting low pH and high metal concentrations. These factors result in the environmental degradation of watercourses. The objective of this study was to develop and evaluate an ecotoxicological screening tool (EST) to prioritise future remediation of streams impacted by AMD. The Bloubank stream drainage system in South Africa, served as study area for this purpose. In the initial EST development phase physicochemical variables were assessed while in the second phase, epilithic filamentous green algae biomass (chl-a mg m(-2)), diatoms and filamentous green algae community structures were employed as bioindicators as well as Daphnia magna toxicity assays. Using a weight of evidence approach, the first three sites receiving AMD were critically and seriously modified, followed by site 4 that was modified. Sites 1-3 with EST scores ≤70% were assessed as priority candidates for future restoration.

Assessment of microbial infection risks posed by ingestion of water during domestic water use and full-contact recreation in a mid-southern African region.

A customised Water-related Quantitative Microbial Risk Assessment (WRQMRA) process was used to determine risk of infection to water ingested by users in the south-eastern Free State, South Africa. The WRQMRA consisted of an observed-adverse-effect-level approach (OAELA) and a quantitative microbial risk assessment (QMRA). The OAELA was based on the occurrence of E. coli in the study waters to determine the possible risk of infection and the QMRA probable risk of infection by salmonellae. The WRQMRA was applied to recreational surface resource waters as well as waters from an unprotected spring and waters from the treated municipal supply that were stored in containers for domestic purposes. E. coli numbers were measured against expected infection levels expressed in water quality guidelines, while Salmonella counts were calculated to give the probable infection risk (Pi). Ingestion was based on intake volumes compiled for the various water uses. E. coli occurred in numbers <10(6) in the surface waters, while the untreated spring and treated supply water contained E. coli of <10(2) and <10(1) respectively. Salmonella occurred in numbers of <10(3) in recreational waters, and <10(-1) in water used for domestic purposes. A single exposure to the mean (as well as 95th percentile) risk was calculated using a beta-Poisson dose-response model at ingestion volumes of 100 mL (for full-contact recreation) and 1,318 mL (for domestic water use). Both the OAELA and the QMRA approaches indicated a risk of infection to recreational and domestic water users, even for a single exposure event, with the OAELA either over- or under-estimating the risk of infection for singular exposure events. This indicated that this method, used on its own, could not reliably predict a realistic risk of infection. It is recommended that the full WRQMRA process be used, and further developed to address several uncertainties that became evident during this study.

Development and implementation of drinking water quality management procedures for rural communities: South African case studies

El impacto de las enfermedades de origen hidrico en Sudafrica es significativo, ya que la diarrea es la principal causa del 20 de las muertes entre 1 y 5 años y la calidad del agua en las comunidades rurales es pobre. Se brinda un panorama de la situacion en Sudafrica, se propone la puesta en marcha de procedimientos de evaluacion y monitoreo para revertir la situacion hacia niveles de calida de agua mas aceptables, y se describe el exito obtenido en seis comunidades rurales

Development and implementation of drinking water quality management procedures for rural communities: South African case studies

El impacto de las enfermedades de origen hidrico en Sudafrica es significativo, ya que la diarrea es la principal causa del 20

de las muertes entre 1 y 5 años y la calidad del agua en las comunidades rurales es pobre. Se brinda un panorama de la situacion en Sudafrica, se propone la puesta en marcha de procedimientos de evaluacion y monitoreo para revertir la situacion hacia niveles de calida de agua mas aceptables, y se describe el exito obtenido en seis comunidades rurales

The effect of water supply, handling and usage on water quality in relation to health indices in a developing community in South Africa.

PIP: This study examined the relationship between the quality of water consumed by people in a developing community in South Africa, and health outcomes for diarrhea. Water sources included no formal water supply, communal taps used by over 100 people, outdoor taps on individual plots, and indoor taps. The aim of this 3-year study was to determine water quality at point of collection, to examine patterns of water usage, and to determine the health consequences. This was a case control study and epidemiological assessment. The sample included over 300 households. Cases included pre-school children with severe diarrhea who visited a health facility in the study area. Interviews were conducted to determine hygiene, sanitation, education, and socioeconomic information. Controls of similar age and type of water supply were obtained from neighborhoods in the study area. Findings indicate that water, based on microbiological assay, was of good quality and complied with the South African Bureau of Standards. Water was significantly more contaminated after handling and storage compared to point of source. Cases and controls had equally poor water quality after collection and storage. Control indoor cases had higher levels of E. coli. There was a strong association between diarrhea and the attendance at a day care center. Increased risk of diarrhea was associated with poor kitchen hygiene and low levels of knowledge about hygiene and diarrhea prevention. Communal tap facilities had lower water quality than private taps.^ieng

The health effects of exposure through swimming in South African marine waters: an overview.

PIP: This study evaluated the health effects of exposure to pathogenic microorganisms in South African marine waters during 1990-94. About 20% of South Africa's coastline is used for recreational purposes. The prospective study was conducted on 4 beaches and a tidal pool in the Western Cape Province in 1990. The sample included about 16,000 participants willing to provide information at the time of contact and at a follow-up date. The aim was to assess the health risks, to establish the relationships between swimming and water quality and health outcomes, and to recommend appropriate microbiological indicators. Prospective trials were discretely carried out during the peak holiday season. The trials relied on methods established by Cabelli (1982) and endorsed by the US Environmental Protection Agency (EPA) in 1986, and the World Health Organization in 1991. Water quality samples were obtained on recruitment days for fecal coliforms, E. coli, fecal streptococci, staphylococci, and coliphages. Findings indicate that the microbiological quality of the water on the 4 beach sites complied with both existing South African standards and US EPA guidelines. The tidal pool showed signs of pollution with fecal coliforms, fecal streptococci, and staphylococci. Water quality varied on different days. Further analysis is being conducted on the different levels of water quality. All sites showed an increased health risk for swimmers compared to nonswimmers. Site 2 showed a statistically significant risk. A prior pilot study found some evidence of a relationship between swimming-related illness and water quality.^ieng