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| Author(s): |
Izabel Adelina Ribeiro
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR) |
| Defense date: | 1998-02-18 |
| Examining board members: |
Samuel Murgel Branco;
Antonio Eduardo Giansante;
Aristides Almeida Rocha
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| Advisor: | Samuel Murgel Branco |
| Abstract | |
The common onion Allium cepa. L., due to its excellent chromosome conditions, has been widely used as a test system for examining the citogenetic effects of several chemical compounds on biological material. It has been observerd, in monitoring environmental studies, some growth restriction on Allium roots when they are exposed to wastewater from chemical factories. In this study, we evaluate these test systems by choosing some hard metals which harmful effects on biological materials has been already described. Furthermore, some factors that could interfere on the results, such as: temperature; light; water quality and onion quality were studied. The lowest concentration (1.5 mg/l) for cadmium and cupper were found to have hard capacity to inhibit root growth. The zinc showed moderate toxicity at 1.5 mg/l and this effect was more evident at increased concentrations. The industrial wastewater that contains mixture of nickel and sulphate or cupper and cyanate inhibited root growth at lower concentration (0.7%). These results showed that the test system has high sensitivity for hard metals. There was no direct influence of temperature and light on the experiment conditions. With regard to the type of water, tap water should not be used because of inhibition on the root growth caused by zinc and copper. The results contradicted a potential osmotic effect of distillated water, being convenient to add 100 - 250 mg/l of NaCl. The best response was obtained with onions from Argentina with 3.5 - 4.0 cm of diameter being recommended to keep the onion peel for avoiding dryness. (AU) | |