EFFECT OF DIFFERENT PERIODS OF IRRIGATION AND ASCORBIC ACID ON GROWTH, YIELD AND QUALITY OF ESSENTIAL OIL OF MENTHA PIPERITA L. PLANTS

The present study was carried out during two growing seasons (2019 and 2020) at the Nursery of Department of Floriculture, Ornamental Horticulture, Faculty of Agriculture, Alexandria University, Egypt to study the effect of irrigation intervals (4 days as control stress, 8 days as moderate stress and 12 days as severe stress) and ascorbic acid (AsA) at 0, 100, 150, 200, 250 mg l-1 on the growth, quantity and quality of the essential oil of Mentha piperita L. plants. The main results of this study indicated that most of the vegetative growth characteristics were increased when AsA was applied at 150 or 200 mg l-1 to the plants grown under control stress (irrigation interval at 4 days). AsA at 200 mg l-1 was more effective on leaves fresh weight than 150 mg l-1 which affects mostly the number of branches of the plants grown under moderate stress (irrigation interval at 8 days). Increasing irrigation interval to 12 days (severe stress) in addition to AsA at 200 mg l-1 decreased the harmful effects in most peppermint plants and leads to obtain high oil percentage and yield. Peppermint oil was analyzed according to GC analysis of fresh leaves grown under water stress and sprayed with ascorbic acid with different concentrations identified 9 components, the major component was menthol with an average of 34.55-52.67% during the three cuts. In general, there was a direct relationship between increasing irrigation intervals and oil components percentage (menthol, menthone and limonene). These results suggest that normal water deficit (4 days irrigation interval) in peppermint will be appropriate to enhance better growth and productivity. In addition, ascorbic acid treatment reduced the damaging action of water stress, especially at concentrations of 150 and 200 mg l-1, so we can conclude that these concentrations are sufficient enough to support peppermint growth, leaves fresh weight and consequently maximum oil yield

Erratum: Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

Interpretation: By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning

Exposure assessment of heavy metals pollution enriched in core sediment samples of river Nile, Aswan, Egypt

The river Nile is a dominating physical feature of the north- eastern part of the African continent, covering areas exhibiting varieties and contrasts in topography, climate vegetation and people. So, in this study, we estimated the contamination of the Nile sediment with some major and trace heavy metals in core samples which can cause some undesirable health effects. Concentrations of all elements shows that the maximum enrichment is found in the top subsamples, while the most elements shows low contents in the lower layer reflecting the impact of human activity on the sediment contents. Different normalizing methods were used, i.e. geoaccumulation (Igeo) and enrichment factor (EF), for the influence of the natural variability in sediment mineralogy and to assess whether the concentrations observed in surface sediment represent background or contaminated levels. The study has also shown the importance of different sediment characteristics in spatial distribution of heavy metals in the sediments of river Nile. To protect the ecological system of river Nile watershed, industrial mining and agricultural activities along river stream should to be strictly regulated