|Presence, concentrations and potential implications of HIV Anti-Retrovirals in selected water sources in South Africa
|Expanded Title:||In 2013 an estimated 6.3 million people in South Africa were living with HIV and AIDS. In 2013, 200 000 were estimated to have died from this disease. South Africa as a country currently has the greatest number of people that use HIV anti-retrovirals (HIV-ARVs) as anti-retroviral therapy (ART) in the world. Some of the
HIV-ARVs used in South Africa include Zidovudine, Satvudine, Lamivudine, Nevaripine, Indinavir and Ritonavir. HIV-ARVs are used in combination therapies, called Highly Active Antiretroviral Therapy (HAART).
A daily dose of combination therapy of HIV-ARVs (mean of 991 mg/day/person, range 590-1996) equates to an approximate total of 529 000 kg of HIVARV compounds ingested per year (assuming 1.5 million people on ART). Excretion of HIV-ARVs varies depending on the compound, but some such as Tipranivir, are
excreted at 80%, and Nevaripine at 2.7% via urine. Assuming a mean 30% excretion to sewage via urine and faeces, it is estimated that about 159 000 kg of HIV-ARV could reach the aquatic systems of South Africa every year, but this is based on assumptions. From the above it is obvious that PPCPs can be
expected in natural waters in South Africa. Fish and other aquatic biota are therefore exposed to and may even accumulate HIV-ARVs directly from water via their gills, through food, or both. It is not known what effects these exposures and/or accumulation may have. Fish in this project will serve as a distant surrogate
for secondary human exposure, acknowledging that fish might be exposed to much higher concentrations in natural waters than humans would through drinking water.
The following were the aims of the project:
1. To conduct a literature survey on HIV-ARV presence in the environment.
2. To determine the major HIV-ARV compounds used in SA.
3. Develop extraction and analytical procedures for selected HIV-ARVs from water and fish.
4. Collect treated wastewater from four different wastewater treatment works, at least three rivers, and at
least three impoundments.
5. Collect fish from the same sites as for the natural waters.
6. Analyse the water and fish as per developed methodology.
7. Analyse and interpret the data, generate conclusions and recommendations, and report via various means.
An analytical method was developed to extract and quantify determination of 11 antiretroviral drugs (Abacavir, Efavirenz, Didanosine, Lamivudine, Lopinavir, Nelfinavir, Nevirapine, Ritonavir, Stavudine, Saquinavir, Tenofovir, and Zidovudine) in water and fish. The Horizon Technology’s SPE-DEX 4790
automated extraction system, the Horizon Technology DryVap® Concentrator System, and the HPLC/QTOFMS
(Agilent Technologies, Germany) consisting of a HPLC (High pressure liquid chromatograph) (series Presence, concentrations and potential implications of HIV-ARVs in selected water sources in South Africa
1100) and 6540 Accurate Mass QTOF-MS (Quadrupole time-of-fight – Mass spectrometer) were used for extraction, evaporation and analysis of samples, respectively. From a list drawn up of presently used HIVARVs in SA, the following were selected for this study: Stavudine, Lamivudine, Zidovudine, Abacavir sulfate,
Efavirenz, Nevirapine, Saquinavir, Mesylate, Ritonavir, Nelfinavir, Didanosine, Lopinavir and Tenofovir.
Quantification was done using standards. The LOQ (Limit of Quantification) was defined as the lowest
calibration point in the linear regression (determined by MassHunter), with a signal to noise ratio of 10.
Calibration curves showed excellent linearity over the calibration range, with correlation coefficients greater than 0.90 for all analytes. LOQs ranged between 0.02-1.0 ng/l, and recoveries from spiked water ranged between 88-108%.
RESULTS AND DISCUSSION
More than 100 samples were collected, composed of natural water, drinking water (including bottled water),
fish plasma, and also groundwater. Sample collection was successfully completed and fish blood samples
were collected from five different dams and rivers. Efavirenz and Saquinavir were not detected in any of the 47 natural water samples. All other compounds were detected at least once, with Nevirapine found in six samples. The lowest concentration was 0.3 ng/l (Zidovudine) and the highest was Nevirapine at 6.7 ng/l. Of the four WWTP treated effluent samples, only Nevirapine (0.4 ng/l), Zidovudine (0.3 ng/l) and Tenofovir were quantified in two of the WWTPs. Of the 31 drinking water samples, Lamivudine, Tenofovir, Efavirenz, Lopinavir, and Saquinavir were not quantifiable. Nevirapine occurred in five samples (0.3-3.5 ng/l), and Didanosine in three (0.4-3.3 ng/l). Stavudine, Nevirapine, Tenofovir, Nelfinavir and Saquinavir were quantified from seven of 18 ground water samples. Nevirapine was found in eight (0.3-5.4 ng/l). In 33 fish plasma samples from four sites, nine samples had quantifiable amounts of HIV-ARVs: Stavudine (n=2),
Didanosine (n = 3), Abacavir (n = 1), Efavirenz (n = 1), Nelfinavir (n = 1), and Saquinavir (n = 2). Plasma concentrations ranged from 5.4-22 ng/l. All sites, including a supposed ‘clean site’, upstream of Upington, had one or more quantifiable HIV-ARV residues. No HIV-ARVs were detected in any of the 25 bottled water samples. Due to the scattered nature of sample locations, and the variable presence and concentrations in samples, no meaningful statistics could be done.
The sampling, extraction, and analytical procedures used, successfully provided quantifiable concentration
data for HIV-ARVs in environmental samples. All eleven HIV-ARVs were quantifiable in at least one matrix.
Two of the four WWTPs had quantifiable amounts of HIV-ARVs in their effluent, indicating that effective removal (below LOQ) is possible. The likely (unconfirmed) presence of many other compounds in the water samples analysed also indicates that other PPCPs, pesticides, and industrial pollutants, may be present. If mainly unstable HIV-ARVs are found in the samples that were analysed, it is therefore likely that similar
unstable compounds would be present, and indicates that more stable compounds, whether PPCPs or other, will also survive intact for variable periods in waters. The unconfirmed likely presence of many compounds in our waters needs urgent attention to inform the need for more protection of the sources, as well as the ecology and consumers.
|Document Type:||Research Report
|Document Subjects:||Mine water - Mine water treatment
|Document Keywords:||Health, Water Quality
|Document File Type:||pdf
|Research Report Type:||Standard
|WRC Report No:||2144/1/14
|Authors:||Swanepoel C; Bouwman H; Pieters R; Bezuidenhout C
|Organizations:||North West University
|Document Size:||468 KB