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Introduction
Patricks works at the Department of Zoology and Entomology, University of the Free State. Patricks does research in Molecular Biology, Biomarkers and Environmental toxicology
Publications
Publications (43)
To alleviate the burden of water contamination, a newly developed form of bioremediation known as mycofiltration can be employed. Mycofiltration is an environment-friendly technology involving the treatment of contaminated water by passing it through a network of saprophytic fungal mycelium. A mycofilter made of Pleurotus ostreatus was used for the...
We look at the link between climate change and vector-borne diseases in low- and middle-income countries in Africa. The large endemicity and escalating threat of diseases such as malaria and arboviral diseases, intensified by climate change, disproportionately affects vulnerable communities globally. We highlight the urgency of prioritizing researc...
Research on wastewater treatment processes in Maluti-a-Phofung Municipality (South Africa) has revealed that substandard wastewater management in this region contributes to terrestrial and aquatic pollution. Because this pollution poses a threat to the environment, there is a pressing need to reduce the environmental impact of poorly managed sewage...
With an obsolete livestock sector, Gabon relies on its huge hydrographic network rich in fish to supply its populations with animal proteins. This study aimed to conduct metal analyses in four fish species (Oreochromis niloticus, Clarias gariepinus, Chrysichthys nigrodigitatus, Polydactylus quadrifilis) frequently consumed by human populations in t...
Introduction: Water quality assessment is a fundamental requirement for
comprehensive water management. Access to water is not exclusively a
quantitative issue, as human activities often lead to negative impacts on water
quality due to pollution. This results in a need for the systematic monitoring of
water bodies to surveil ongoing pollution dynam...
Since the establishment of a free economic zone and a simultaneous increase in the population of the QwaQwa region, aquatic systems of the area were expected to undergo an increase in metal contamination. The aims of this study were to assess the quality of sediments from the Metsi-Matsho, Namahadi and Elands Rivers of the QwaQwa region, and to inv...
Earthworm functional group assemblages vary with land cover/use in human-impacted landscapes of Sudano-Guinean area, Cameroon, Environmental Challenges (2023), doi: https://doi. Abstract The semiarid zones of Cameroon are experiencing rapid land degradation and desertification due to climate change and human activities. Earthworms play a crucial ro...
This study sets out to develop an understanding of how the cumulative impacts of extreme weather events may affect the vulnerability of local communities in QwaQwa and how these impacts may be ameliorated through disaster risk reduction and resilience building. To fully comprehend the extent and impact of climate-related risks in QwaQwa, a downscal...
Simple Summary
Hoverflies are regarded as the second most important pollinators after bees. They also provide important environmental services including the biodegradation of organic wastes, as well as the predation of pests. Hoverflies are usually divided into several groups or regions including the Holarctic, the Oriental, the Australasian and th...
Dietary restriction (DR) and dietary deprivation (DD) have been shown to be significantly beneficial in terms of lifespan gains and stress alleviation in invertebrate and vertebrate species. Such beneficial effects, however, have yet to be clearly assessed in the presence of chemical stressors. We conducted a comparative evaluation of the toxicity...
A mycofilter made of Pleurotus ostreatus was used for the removal of iron (III) and imidacloprid from aqueous solutions. Batch mycofiltration, at a dosage of 1g of mycofilter per 50 ml, was performed on iron (III) solutions of different concentrations (0.99, 10.7, 22.9, and 27.72 mg/L) and pH (3.3, 7 and 11). For column mycofiltration, the mycofilt...
Mycofiltration via continuous fixed bed adsorption, helped to assess the effect of flow rate, pH, column bed height and myceliation on the sorption capacity of a mycofilter. The mycofilter (thatching straw and Pleurotus ostreatus) was cultured and loaded into polypropylene columns (2.5_12 cm) to bed heights of 2 and 4 cm. A food color solution was...
SAGE notes, with concern, cholera-related deaths in Gauteng (centred in Hammanskraal),
the Free State, and Mpumalanga, in May 2023. While the source of Hammanskraal’s deadly
outbreak is yet to be established, SAGE takes the position that several factors have likely
contributed to the outbreak, including dysfunctional wastewater treatment facilities...
There are growing concerns on contribution of vegetation dynamics to atmospheric turbidity and quality of regional water towers. The study sought to determine the trends in the MODIS/TERRA-derived normalized difference vegetation index (NDVI) and aerosol optical depth (AOD) for Lesotho Highland over 2000-2020. The predictive relationship between th...
In holometabolous insects, life-history characteristics can vary in response to diet. The main aim of this contribution was to examine which diet best promotes larval development and survival of the aquatic saprophagous hoverfly Eristalis tenax L. (Diptera: Syrphidae). This study was motivated by a need to optimize techniques for rearing these inse...
Phuthaditjhaba is situated at the foothills of the Maloti-Drakensberg, one of southern Africa’s primary water-producing regions. Nevertheless, the region suffers from a recurring lack of sufficient water for domestic and agricultural use. Since 2015, this chronic water crisis has created a state of conflict between the inhabitants of the region and...
Copper oxide nanoparticles (CuO‐NP) can be applied as efficient alternative to conventional Cu in agriculture. Negative effects of CuO‐NP on soil organisms were found, but only in clay‐rich loamy soils. It is hypothesized that clay‐NP interactions are the origin of the observed toxic effects. In the current study, artificial OECD soils containing 3...
A major point of concern in ecotoxicology is the effects of pesticides on nontarget organisms. This can impact the ecological role played by certain beneficial species in nature. Regarding neonicotinoid insecticides such as imidacloprid (IMI), several measures, including limited trade, restrictive use, and ban have been implemented in Europe and th...
The behavior, i.e., observable response of an organism can serve as a useful indicator of environmental quality. In the absence of death and other sublethal effects, behavioral changes can represent early warning signs of toxic effects. In the present contribution, we present two novel bioassays useful for the quick assessment of chemical effects o...
Despite several known beneficial attributes, biochar is suspected to cause harm to soil organisms when present in relatively high quantities in the soil. To determine the potential detrimental effects of biochar, for 96 h, we exposed the earthworm Eisenia fetida to 0, 2, 4 and 8 mg glyphosate (GLY) per kg in non-amended and biochar-amended soil at...
Background
Mycofiltration is an environment friendly technology which involves the treatment of contaminated water by passing it through a network of fungal mycelium. This technology has gained momentum over the years, and the systematic review chartered in this protocol will compile and synthesise literature on mycofiltration studies, paying speci...
Research to inform a sustainable future for southern African mountains as socialecological systems requires major investment. This is needed to strengthen existing relationships, build new relationships among academia, policy, and practice, and drive a robust research capacity program. This is particularly important in disciplines where there is cu...
Terrestrial and aquatic ecosystems are increasingly threatened by pesticide pollution resulting from extensive use of pesticides, and due to the lack of regulatory measures in the developing world, there is a need for affordable means to lessen environmental effects. This study aimed to investigate the impact of biochar amendment on the toxicity of...
Nature, climate crisis, and the Anthropocene have carved space in recent inter-, cross-, and multi-disciplinary humanities studies. In South Africa, such studies have barely touched literature in African languages. Nyambi and Otomo focus on the tropes of “lady nature,” nostalgia, and dystopia in Zulu writer Bhekinkosi Ntuli’s Imvunge Yemvelo to exp...
The ingestion of organic and mineral materials by earthworms is a prominent functional role that has profound consequences for the decomposition and stabilization of soil organic matter. To investigate the litter consumption of the African nightcrawler earthworm Eudrilus eugeniae (Kinberg, 1867) under different tropical conditions, (i) we used DNA...
Earthworms exhibit clumping behaviour in and out of the soil. However, it remains unknown if such social behaviour ultimately influences the outcome of ecotoxicological experiments in the laboratory. We performed several overnight avoidance tests to determine whether social behaviour (i.e., local enhancement) is a factor in pollution avoidance beha...
Recently in South Africa, wastewater treatment plants (WWTP) have come under scrutiny because of increased reports of their ineffectiveness to treat wastewater adequately. This study focused on assessing potential health risks for humans exposed to concentrations of heavy metals in river systems that receive effluents from wastewater treatment plan...
We used the Enchytraeid Reproduction Test to evaluate the potential ecotoxic effects
of sewage sludge samples on terrestrial oligochaetes in an Afromontane area. The
sludge samples were collected from two wastewater treatment plants near the towns of
Phuthaditjhaba and Harrismith in the Afromontane region of the eastern Free State in
South Africa....
We conducted avoidance tests at fixed (20 °C) and fluctuating temperature (15/25 °C) for 2 and 7 days to assess the effects of temperature regime and duration of exposure on the avoidance of Enchytraeus albidus towards silver nitrate (AgNO 3) and silver nanoparticles (AgNPs). The metal contents of the worms that avoided both toxicants were measur...
The present study investigated the use of biochar for the alleviation of the toxic effects of a nanosilver colloidal dispersion and a chloronicotinyl insecticide. The survival and reproduction of the potworm Enchytraeus albidus were assessed after exposure to imidacloprid and silver nanoparticles (AgNPs). E. albidus was exposed to 0, 25, 50, 100, 2...
Abstract: Earthworms are present in all types of soil. Changes in land use influence populations of earthworms. However, information on the dynamics of earthworm populations in northern Cameroon is not available. This paper highlights the research carried out on the abundance, biomass, and diversity of earthworm populations throughout four types of...
To test whether metal-tolerant and metal-sensitive earthworm specimens could be an inherent part of metal-free earthworm populations, (i) we used DNA barcoding to identify and categorize earthworms from 8 populations of the standard test species Eisenia andrei, and (ii) the earthworms carrying three of the identified COI haplotypes (named Hap1, hap...
DNA barcoding was used to investigate laboratory and commercial stocks of Eisenia species from four provinces of South Africa. The COI gene was partially amplified and sequenced in selected earthworms from eight local populations (focal groups) and two European laboratory stocks (non-focal groups). Only nine COI haplotypes were identified from the...
Cadmium (Cd) and zinc (Zn) toxicity in Enchytraeus doerjesi after 28-day exposure experiments was studied at 15, 20, and 25 °C. Cd lethal concentration (LC)(50) decreased with increasing temperature (293.01 mg kg(-1) at 15 °C, 261.62 mg kg(-1) at 20 °C, 231.79 mg kg(-1) at 25 °C). In contrast, Zn LC(50) increased with increasing temperature (420.21...
Using the comet assay, the genotoxicity of Cd, Zn and Cd/Zn mixtures in Eisenia andrei was assessed after 4 weeks of exposure at 15, 20 and 25°C. Relative to the controls, significant increases in TDNA% were observed in exposures to Cd alone at 500 and 1,000 mg/kg soil at both 20 and 25°C, while a general decrease occurred at 15°C. For Zn alone, a...
DNA barcoding was used to investigate the phylogenetic delimitations of Eisenia sp. populations used in ecotoxicological research in South Africa. A total of three focal groups (used in published works) and two non-focal groups were assessed. These focal groups, including two laboratory cultures and one field population, have been referred to as Ei...
The enchytraeid reproduction test (ERT) was used to assess the ecotoxicity of selected mine tailings and agricultural soils from South Africa. The mine tailings had higher cumulative metal concentrations than agricultural soils. The most contaminated mine tailings significantly reduced the survival of the oligochaete Enchytraeus doerjesi whose repr...
In a recent study, we showed that the earthworm species Eisenia fetida, inhabiting an extremely high metal polluted compost heap on a wine farm, did not have elevated body loads of the metals but exhibited genotoxic tolerance when exposed to Cd in the laboratory (Voua Otomo and Reinecke, 2010). To unravel the mechanism behind the surprisingly low m...
We studied the effect of salinity on some life-cycle parameters in the collembolan Folsomia candida, the enchytraeid Enchytraeus doerjesi, and two earthworm species, Eisenia fetida and Aporrectodea caliginosa, using natural saline soil from Robertson, Western Cape, South Africa. Specimens of the four species were exposed to soils along a gradient o...
Since life-cycle studies showed that the earthworm species Eisenia fetida can develop increased tolerance after long-term exposure to a sub-lethal concentration of Cd in the laboratory, we assessed both the cytotoxicity and genotoxicity of Cd in a long-term Cd-exposed population. We exposed E. fetida specimens from this population, from a laborator...
Standard test species may differ in their response to toxicants. Accurate identification of test organisms is therefore of critical importance in correctly interpreting data generated from laboratory assays. This is not always possible when species are morphologically similar or where the taxonomy of the group has recently been revised. A case in h...