Die geskiktheid van potwurms (Enchytraeidae) en plante om die toksisiteit van olieraffinadery-slik te toets

Reinecke, Adriaan J. ; Reinecke, Sophia A. ; Van Wyk, Mia (2016-11-24)

CITATION: Reinecke, A. J., Reinecke, S. A. & Van Wyk, M. 2016. Die geskiktheid van potwurms (Enchytraeidae) en plante om die toksisiteit van olieraffinadery-slik te toets. Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie, 35(1), a1382, doi:10.4102/satnt.v35i1.1382.

The original publication is available at http://www.satnt.ac.za

Article

Grondbewerking word in die petrochemiese nywerheid in suidelike Afrika gebruik as ’n metode om van besoedelstowwe ontslae te raak. ’n Historiese grondbewerkingsperseel is by ’n petroleumraffinadery geïdentifiseer waar die gedeponeerde slik uit ’n mengsel van olie en wateroplosbare chemiese besoedelstowwe bestaan wat verskeie gevaarlike chemikalieё insluit. Die doel met die studie was om die toksisiteit van die slik, sowel as grond, op die perseel te bepaal en vas te stel of plante en potwurms gebruik kan word in die bioassessering van die slik, aangesien daar ’n behoefte bestaan om ’n groter verskeidenheid toetsorganismes te gebruik wat verskillende ekologiese nisse verteenwoordig. Ons het eksemplare van ’n grondlewende potwurm (Enchytraeus doerjesi) aan die slik en aan slikbewerkte grond blootgestel en hulle oorlewing, groei, voortplantingsukses en vermydingsgedrag bestudeer. Vyf plantsoorte en hulle sade is aan verskillende konsentrasies van die slik in kommersiёle potgrond blootgestel en hulle ontkiemingsukses, groeikoers en biomassa is bepaal. Die grond van die landbewerkingsperseel was nie akuut toksies vir die potwurms nie en hulle het selfs ’n toename in voortplanting getoon in vergelyking met onbesoedelde grond. Hulle het wel in gedragstoetse erg besoedelde grond vermy. Die bevinding is dat potwurms nie so gevoelig is vir die slik soos erdwurms en springsterte, wat voorheen getoets is nie, maar dat hulle wel bruikbaar is en kan bydra om die toksisiteit en herstelstatus van sulke grond te evalueer, aangesien hulle ’n bykomende ekologiese nis verteenwoordig. Die plante was nie baie gevoelig vir die slik nie en gemengde resultate is verkry. Slaai en gras is die meeste deur die slik geaffekteer, terwyl boontjies die beste gevaar het en hulle groeikoers selfs deur die byvoeging van slik gestimuleer is.

Landfarming is used in southern Africa as a tool to dispose of contaminants in the petrochemical industry. A historically landfarmed site was identified at a petroleum refinery where the sludge deposited on the site consisted of a mixture of oil and water-soluble contaminants which included several hazardous chemicals. The aim of this study was to assess the toxicity of the sludge, as well as of soil from the landfarming site, and to determine if potworms and plants could be used in bioassays since there is a need to identify a variety of test species, representing different ecological niches. We exposed a soil-dwelling potworm (Enchytraeus doerjesi) to the sludge and the landfarming soil to study their survival, growth, reproduction success and avoidance behaviour. Five plant species and their seeds were exposed to different concentrations of sludge in potting soil, and consequently germination success, growth rate and biomass were monitored. The various soils from the landfarming site were not acutely toxic to the potworms and they even showed an increase in reproduction, compared to uncontaminated control soil. They avoided heavily contaminated soil from the landfarming site. We conclude that the potworms were not as sensitive as the earthworms and springtails previously tested. They may nevertheless still be utilised for testing the toxicity and recovery status of such soils, since they represent a different ecological niche and showed an avoidance response to refinery waste. The plants were not very sensitive to refinery sludge and presented mixed results. Lettuce and grass were affected most by the sludge, while beans were the most resistant. With the addition of low concentrations of sludge to the substrate, the growth rate of beans was even stimulated.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100502
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