Showing papers on "Zinc toxicity published in 1977"
TL;DR: At sites with higher zinc levels, populations showed increased resistance to zinc of the filamentous green algae, with H. rivulare at least, that an increase in PO4-P and a decrease in pH may also reduce zinc toxicity, and the data suggest that cadmium is more likely than lead to influence zinc toxicity.
Abstract: SUMMARY. Field and laboratory studies have been carried out on the tolerance to zinc of the filamentous green algae Hormidium rivulare Kutz., H. flaccidum Kutz. and H. fluitans (Gay) Heering growing in flowing waters. Forty-seven different sites in England, France, Germany and Ireland were included, the majority of them chosen to represent examples of zinc pollution resulting from past or present mining activities. All three species were widespread both in waters free of zinc pollution and waters with zinc pollution, and H. rivulare and H. flaccidum were frequent at a site with the highest zinc level included in the survey (mean of 22.8 mg l−1, maximum of 30.2 mg l−1 Zn passing through a filter). At sites with higher zinc levels, populations showed increased resistance to zinc of the filamentous green algae Hormidium rivulare Kutz., H. flaccidum creased resistance being largely, if not entirely, the result of genetic adaptation. An increased frequency of geniculations can occur both as an environmental and a genetic response to very high zinc levels. The application of various statistical analyses to the data suggests that two groups of chemical factors may be influencing the toxicity of zinc in the field. The first group which appears to increase the toxicity of zinc includes cadmium and lead, while the second group, which decreases the toxicity of zinc, includes magnesium, calcium and various hardness factors. As the occurrence of zinc, cadmium and lead in the field are all strongly intercorrelated, it is not possible to distinguish clearly the effects of one from the other, although the data do suggest that cadmium is more likely than lead to influence zinc toxicity. The ‘amelioration’ factors are also strongly intercorrelated in the field, so it is difficult to comment on their relative importance. There is some indication for H. rivulare at least, that an increase in PO4-P and a decrease in pH may also reduce zinc toxicity.
61 citations
TL;DR: Correlation analyses of root and leaf Zn and Fe contents suggested that Zn may interfere with the translocation of Fe; however, Zn toxicity was not associated with a diminished leaf Fe content.
Abstract: Zinc toxicity and Zn-Fe interactions were studied in corn (Zea mays L. var. Barbecue hybrid) grown in hydroponic culture. High Zn greatly reduced the root and shoot fresh weights; increasing Fe largely, but not completely, restored normal growth. Correlation analyses of root and leaf Zn and Fe contents suggested that Zn may interfere with the translocation of Fe; however, Zn toxicity was not associated with a diminished leaf Fe content. Fe did appear to retard both the absorption and the translocation of Zn. The chlorosis of Zn-toxic plants is not attributable to diminshed total leaf Fe; however, this chlorosis is relieved by increasing nutrient Fe. Zn and Fe probably do interact at some site.
57 citations
TL;DR: In this paper, an investigation into the levels of metals in plants growing on metalliferous soils was carried out, and the exchangeable metal concentration of soils from Tyndrum and Trelogan was found to be extremely variable from sample to sample.
Abstract: An investigation into the levels of metals in plants growing on metalliferous soils was carried out. The exchangeable metal concentration of soils from Tyndrum and Trelogan was found to be extremely variable from sample to sample and the influence of soil pH on the exchangeable lead and zinc concentration is discussed. Large differences in heavy metal levels were found between species and may be indicative of different mechanisms of tolerance to lead and zinc excess. Large differences in calcium levels between plant tissues were also found. These may result from the use of calcium in ameliorating lead and zinc toxicity in some species.
46 citations
TL;DR: A more severe anemia was found when zinc and cadmium were fed together than when fed individually, and the low serum iron levels of zinc toxicity were further reduced by low calcium or high vitamin D diets.
24 citations
TL;DR: Suckling lambs maintained for 4 weeks on a milk-substitute diet containing 407 g Toprina yeast/kg dry matter of diet exhibited poor growth, low appetite and extensive renal damage.
Abstract: 1. Suckling lambs maintained for 4 weeks on a milk-substitute diet containing 407 g Toprina yeast/kg dry matter of diet exhibited poor growth, low appetite and extensive renal damage. 2. The batch of yeast used contained 2065 mg zinc/kg. 3. The kidneys of lambs offered a milk diet supplemented with the same Zn content as the yeast-fed diet (32.1 mg Zn/1000 kJ) were similarly affected.
17 citations