Neighbourhood analysis of competition between two Namaqualand ephemeral plant species

By using attributes of neighbours, such as number, size and distance, investigators have developed neighbourhood competition models that are able to predict plant performance of an individual in a plant population. A non-linear neighbourhood model proposed by SiLander & Pacala (1985) was applied to performance data (i.e. total above-ground dry mass) of Dimorphotheca sinuata and Ursinia cakilefolia, two Namaqualand ephemeral species. The best neighbourhood size was sought by varying the neighbourhood size and plotting an interference index against dry mass. The non-linear model was then fitted to the data and the r2 values determined for each neighbourhood. Correlations between performance (total above-ground dry mass) and different interference indices were much higher in mixtures than in monocultures for both species. Number of neighbours seemed to be the best predictor of performance for both D. sinuata and U. cakilefolia in mixtures. In monoculture, the best correlations were obtained when the distance of the neighbours was also taken into account, Even so, these correlations accounted for less than 50% of the variation in plant mass. Although these neighbourhood models may be useful in describing the inter-individual effects of interference on Namaqualand ephemeral species, it may be difficult to apply these results in the field

The prevalence of asthma among children in South Africa is increasing - is the need for medication increasing as well? A case study in the Vaal Triangle

Asthma, a chronic inflammatory condition of the airways, is a global public health concern. In southern Africa the prevalence of asthma has increased over the last few decades. In the current study, all 10-year-old learners from three of the schools (one each in Sasolburg, Vanderbijlpark and Vereeniging) that participated in the 1990 Vaal Triangle Air Pollution and Health Study, were selected as the study population for a cross-sectional study conducted in 2010. Both the 1990 and 2010 studies investigated several exposure factors but focussed on respiratory illnesses as main health outcomes. Although the overall ethnicity profile in 2010 was different from that of 1990, the socioeconomic status of the study populations were very similar – the reason being that the same schools were used and the participating children were from the same immediate environment. The results of the 2010 study were then compared to the results of all 10-year-olds, from the same three schools, who participated in the 1990 study. The results showed the difference in prevalence of asthma during the two study years was statistically significant. The difference in the percentage of children who had ever been diagnosed with asthma and were reportedly on medication in 1990 and 2010 was, however, not statistically significant, indicating that although the prevalence of asthma increased, the demand for medication to control the condition may not have increased as well

Integrating Air-related Health Surveillance into Air Quality Management: Perceptions and Practicalities

Health surveillance is presently not an integral part of air quality management in South Africa, although ambient air pollution standards are derived from health effects of personal exposure. In a survey to air quality officials and environmental health practitioners (n = 361 ), respondents were asked to comment on a discussion document regarding ways to put health onto the air quality management agenda. Less than 7% of the sample (n = 23) responded, the most likely reasons being: overloaded staff; lack of knowledge about air quality-related health; and apathy. All respondents acknowledged their support of the concepts, one suggested inclusion of PM25 and airspora over and above criteria pollutants, and one mentioned use of an indicator 'number of complaints of visual air pollution and odour'. In general, it would appear that the links between air quality and health risks are not well understood and, more importantly, assessing airrelated health outcomes with respect to air quality is not a part of Local Municipalities' Integrated Development Plans. To motivate for necessary changes in Health Information Systems and data management, evidence of valuable application is required. Without readily available health facility and local municipality-specific data on respiratory and cardiovascular illnesses, it will prove difficult to track whether implemented air pollution mitigation measures will have positive health impacts

Risk perceptions of dust and its impacts among communities living in a mining area of the Witwatersrand, South Africa

Mining is a major economic activity in many developing countries. In South Africa, gold mining has played a significant role in the development and sustenance of the country's economy, with both positive and negative consequences. In gold mining areas, tailings dams and mine dumps are significant sources of ambient dust, known to be a nuisance, and health risk, to communities living near them and who must find appropriate coping mechanisms to protect themselves. A qualitative study based on five focus groups with sixty-two participants of different ages and sex was carried out in the Witwatersrand mining district of South Africa. All focus groups agreed that they had noticed dust in the air where they live, stating that the dust came largely from mine dumps but also from other sources. They agreed that the dust causes, among others, health problems, and both short-term and long-term coping mechanisms for protecting themselves against excess dust were mentioned yet considered inadequate, i.e. closing windows and doors, watering their yards, paving their yards and planting trees. Little support from government, mines and other organisations was identified as an important perceived barrier to resolving the dust problem. Means for communication of communities' perceptions of the impacts, risks and possible mitigation / adaption measures associated with dust need to be created and supported in a formal risk management plan

Investigating Air Quality and Air-related Complaints in the City of Tshwane, South Africa

To determine the impact of implemented air quality interventions beyond ambient air pollution reductions, indicators need to be identified and appropriate health data need to be routinely collected to track airrelated health. Presently, the only regulated environmental health performance indicator routinely collected as part of air quality management is the air-related complaint lodged by the public. Here, five years of air-related complaints (n = 875) made by residents in the City of Tshwane (Pretoria, Gauteng)were analysed and considered in relation to ambient SO and PM concentrations monitored at 2 10 permanent air quality monitoring stations. When considering exceedances of the National Ambient Air Quality Standards, there were 17 complaint days with either an SO or PM daily average concentration 2 10 exceedance. However, it was very difficult to make meaningful conclusions about the relation between ambient AQ and air-related complaints given social, economic and data challenges and constraints. There is a real need to have local, air-related health data, for example, upper and lower respiratory tract infections, asthma, etc, generated at clinics and hospitals delivered directly and on an on-going, continuously updated basis to those responsible for implementation of air quality management plans

Human health risk assessment of airborne metals to a potentially exposed community: a screening exercise

Exposure to high concentrations of inhalable particulate matter (PM) is a known human health risk, depending on the chemical composition of the PM inhaled. Mogale City (Gauteng) is known for having several sources of airborne PM, however, less is known about the metals in the airborne PM. The aim of this study was to determine the metals in measured PM at Kagiso, Mogale City. An independent PM10 monitor was installed at the municipality’s existing monitoring site. This monitor continuously monitored PM10 between 23 August and 9 October 2013 and simultaneously sampled particles below 20 μm in diameter onto a glass fibre filter. This filter was replaced once towards the middle of the monitoring period. These two filters were chemically analysed to determine their metal content (30 metals) by the South African Bureau of Standards accredited laboratory at the Council for Scientific and Industrial Research by means of Inductively Coupled Plasma Spectroscopy (ICPS) based on the US EPA Method IO-3.1. To provide an estimate of possible health risk, the metal concentrations were used in a screening US-EPA human health risk assessment (HHRA). Since the analysed metals were reportedly below the detection limit, three hypothetical exposure scenarios (S) based on US-EPA recommendations were created for the HHRA. In S1, concentrations were considered to be the same as the detection limit for each metal; S2 assumed concentrations to be 50% of the detection limit; and S3 put concentrations at 10% of the detection limit. Potential risks (should pollution worsen) of developing respiratory and neurological effects were identified depending on the hypothetical scenarios. Continuous long-term monitoring and chemical characterisation are necessary to confirm these preliminary findings.CSIR Strategic Research Platform Granthttp://www.cleanairjournal.org.zaam201

Future research directions on the “Elusive” White Shark

White sharks, Carcharodon carcharias, are often described as elusive, with little information available due to the logistical difficulties of studying large marine predators that make long-distance migrations across ocean basins. Increased understanding of aggregation patterns, combined with recent advances in technology have, however, facilitated a new breadth of studies revealing fresh insights into the biology and ecology of white sharks. Although we may no longer be able to refer to the white shark as a little-known, elusive species, there remain numerous key questions that warrant investigation and research focus. Although white sharks have separate populations, they seemingly share similar biological and ecological traits across their global distribution. Yet, white shark’s behavior and migratory patterns can widely differ, which makes formalizing similarities across its distribution challenging. Prioritization of research questions is important to maximize limited resources because white sharks are naturally low in abundance and play important regulatory roles in the ecosystem. Here, we consulted 43 white shark experts to identify these issues. The questions listed and developed here provide a global road map for future research on white sharks to advance progress toward key goals that are informed by the needs of the research community and resource managers