An LC-MS/MS based survey of contaminants of emerging concern in drinking water in South Africa

Advances in many analytical techniques allow the detection of compounds in water at very low concentrations (ng/L), which has facilitated the identification of many compounds in drinking water that went previously undetected. Some of these compounds are contaminants of emerging concern (CECs), which is broadly defined as any chemical or microorganism that is not currently being routinely monitored but has recently been identified as being present in the environment, and that may pose health or ecological risks. CECs can include pharmaceuticals, personal health care products and pesticides. Some CECs can act as endocrine disruptors, interfering with the normal functioning of the human endocrine system, potentially influencing foetal and child development. Although the level of many of these compounds are orders of magnitude below known acute toxicity levels, the health impact of long term exposure at low levels is mostly unknown. In this study, we present the results of a national survey over four seasons of potential CECs in the drinking water of major South African cities. The contaminants most often detected were the related herbicides atrazine and terbuthylazine, and the anticonvulsant and mood-stabilising drug, carbamazepine. The levels of these CECs were well below maximum levels proposed by the World Health Organization and the US Environmental Protection Agency. However, the range of CECs detected in drinking water, and seasonal and geographic variability in CECs levels, warrant a more frequent screening programme

Assessing the effects of climate change on distributions of Cape Floristic Region amphibians

Climatic changes have had profound impacts on species distributions throughout time. In response, species have shifted ranges, adapted genetically and behaviourally or become extinct. Using species distribution models, we examined how changes in suitable climatic space could affect the distributions of 37 endemic frog species in the Cape Floristic Region (CFR) – an area proposed to have evolved its megadiversity under a stable climate, which is expected to change substantially in future. Species distributions were projected onto mean climate for a current period (1950 to 2000), hindcasted to palaeoclimate (Last Glacial Maximum; LGM ≈ 21 kya and Holocene Glacial Minimum; HGM ≈ 6 kya) and forecasted for two emissions scenarios (A2a and B2a) for the year 2080. We then determined the changes in area sizes, direction (longitude and latitude), fragmentation index and biotic velocity, and assessed if these were affected by life-history traits and altitude. We found that the biotic velocity at which the CFR amphibian community is expected to shift north (A2a ≈ 540.5 km/kya) and east (B2a ≈ 198 km/kya) far exceeds historical background rates (≈1.05 km/kya, north and west ≈ 2.36 km/kya since the LGM). Our models further suggest that the CFR amphibian community has already lost about 56% of suitable climate space since the LGM and this loss is expected to accelerate under future emission scenarios (A2a ≈ 70%; B2a ≈ 60%). Lastly, we found that highland species were more fragmented than lowland species between the LGM and current period, but that the fragmentation of lowland species between current and future climates is expected to increase

An LC-MS/MS based survey of contaminants of emerging concern in drinking water in South Africa

Advances in many analytical techniques allow the detection of compounds in water at very low concentrations (ng/L), which has facilitated the identification of many compounds in drinking water that went previously undetected. Some of these compounds are contaminants of emerging concern (CECs), which is broadly defined as any chemical or microorganism that is not currently being routinely monitored but has recently been identified as being present in the environment, and that may pose health or ecological risks. CECs can include pharmaceuticals, personal health care products and pesticides. Some CECs can act as endocrine disruptors, interfering with the normal functioning of the human endocrine system, potentially influencing foetal and child development. Although the level of many of these compounds are orders of magnitude below known acute toxicity levels, the health impact of long term exposure at low levels is mostly unknown. In this study, we present the results of a national survey over four seasons of potential CECs in the drinking water of major South African cities. The contaminants most often detected were the related herbicides atrazine and terbuthylazine, and the anticonvulsant and mood-stabilising drug, carbamazepine. The levels of these CECs were well below maximum levels proposed by the World Health Organization and the US Environmental Protection Agency. However, the range of CECs detected in drinking water, and seasonal and geographic variability in CECs levels, warrant a more frequent screening programme

An LC-MS/MS based survey of contaminants of emerging concern in drinking water in South Africa

Advances in many analytical techniques allow the detection of compounds in water at very low concentrations (ng/L), which has facilitated the identification of many compounds in drinking water that went previously undetected. Some of these compounds are contaminants of emerging concern (CECs), which is broadly defined as any chemical or microorganism that is not currently being routinely monitored but has recently been identified as being present in the environment, and that may pose health or ecological risks. CECs can include pharmaceuticals, personal health care products and pesticides. Some CECs can act as endocrine disruptors, interfering with the normal functioning of the human endocrine system, potentially influencing foetal and child development. Although the level of many of these compounds are orders of magnitude below known acute toxicity levels, the health impact of long term exposure at low levels is mostly unknown. In this study, we present the results of a national survey over four seasons of potential CECs in the drinking water of major South African cities. The contaminants most often detected were the related herbicides atrazine and terbuthylazine, and the anticonvulsant and mood-stabilising drug, carbamazepine. The levels of these CECs were well below maximum levels proposed by the World Health Organization and the US Environmental Protection Agency. However, the range of CECs detected in drinking water, and seasonal and geographic variability in CECs levels, warrant a more frequent screening programme

The Photosynthetic Efficiency and Carbohydrates Responses of Six Edamame (<i>Glycine max</i>. L. Merrill) Cultivars under Drought Stress

Vegetable-type soybean, also known as edamame, was recently introduced to South Africa. However, there is lack of information on its responses to drought. The aim of this study was to investigate the photosynthetic efficiency and carbohydrates responses of six edamame cultivars under drought stress. Photosynthetic efficiency parameters, including chlorophyll fluorescence and stomatal conductance, were determined using non-invasive methods, while pigments were quantified spectrophotometrically. Non-structural carbohydrates were quantified using Megazyme kits. Structural carbohydrates were determined using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Drought stress significantly increased the Fv/Fm and PIabs of AGS429 and UVE17 at pod filling stage. Chlorophyll-a, which was most sensitive to drought, was significantly reduced in AGS429 and UVE17, but chlorophyll-b was relatively stable in all cultivars, except UVE17, which showed a significant decline at flowering stage. AGS354 and AGS429 also showed reduced chlorophyll-b at pod filling. UVE17 showed a significant reduction in carotenoid content and a substantial reduction in stomatal conductance during pod filling. Drought stress during pod filling resulted in a significant increase in the contents of trehalose, sucrose and starch, but glucose was decreased. Chlorophyll-a positively correlated with starch. The FTIR and XRD results suggest that the cell wall of UVE14, followed by UVE8 and AGS429, was the most intact during drought stress. It was concluded that carotenoids, stomatal conductance, starch and hemicellulose could be used as physiological/biochemical indicators of drought tolerance in edamame. This information expands our knowledge of the drought defense responses in edamame, and it is essential for the physiological and biochemical screening of drought tolerance