Klip

Abstract: The Klip River wetland is one of the most economically important ecological river system in South Africa as it plays two roles: water purification in the Vaal River system and is also a source of water. However, several studies have demonstrated that the wetland is extremely degraded and has lost capability to perform the two functions. The main objective of this study was to evaluate the Klip River water quality compliance with guidelines for its designated uses i.e. domestic, aquatic and agricultural uses. Furthermore, risks associated with these uses were established. Water samples were collected at 12 points along the Klip River, monthly from February 2016 to January 2017 and analysed for heavy metal pollution using Inductively Coupled Plasma Mass Spectrometry (ICPMS). The environmental risk assessment was done using the Heavy Metal Pollution Index (HPI), Potential Ecological Risk Index (PERI) and the Comprehensive Risk Index. Findings revealed that the HPI for aquatic, domestic and agricultural uses were far above the critical index rendering the Klip River unfit for domestic and agricultural uses; and sustaining aquatic life. Furthermore, at a majority of the sampling sites along the profile of the Klip River, the PERI was very high suggesting that there is a serious threat to ecological communities. It can be concluded that there is a significant threat to ecological communities in the Klip River from heavy metal pollution. Therefore, it is recommended that programs to rehabilitate and restore the Klip River wetland should be developed.

Abstract: The recent algal history of De Klip is outlined and opportunities for collecting soil samples, their nature, the uses of soil cultures both scientific and educational, the longevity of the soil and methods of storing are discussed. The nature of De Klip soil is described and an outline of the procedure followed in making the soil cultures is given. Details of three typical cultures follow with a comparison of the results. Two new species obtained in these cultures are described, Chlamydomonas capensis and ?Pedinopera africana. It is specially fitting that its subject should be cultures of soil from “The Rock” since Professor Pringsheim has shared with me the wonder and joy aroused by the extraordinary fertility of De Klip soil.

Abstract: The distribution of organic compounds in stored lipids affects their migration, transformation, bioaccumulation, and toxicity in organisms. The storage lipid/water distribution coefficient (log Klip/w) of organic chemicals, which quantitatively determines such distribution, has become a key parameter to assist their ecological security and health risk. Due to the impossibility to measure Klip/w values for a huge amount of chemicals, it is necessary to develop predictive approaches. In this work, a quantitative structure-property relationship (QSPR) model for estimating log Klip/w values of small organic compounds was constructed based on 305 experimental log Klip/w values. Quantum chemical descriptors and n-octanol/water partitioning coefficient were employed to characterize the intermolecular interactions that dominate log Klip/w values. The hydrophobic and electrostatic interactions and molecular size have been found to play important roles in governing the distribution of chemicals between lipids and aqueous phases. The regression (R2 = 0.959) and validation (Q2 = 0.960) results indicate good fitting performance and robustness of the developed model. A comparison with the predictive performance of other commercial software further proves the higher accuracy and stronger predictive ability of the developed Klip/w predictive model. Thus, it can be used to predict the Klip/w values of cycloalkanes, long-chain alkanes, halides (with fluorine, chlorine, and bromine as substituents), esters (without phosphate groups), alcohols (without methoxy groups), and aromatic compounds.