Insights into hazardous solid waste generation during COVID-19 pandemic and sustainable management approaches for developing countries

Journal of Material Cycles and Waste Management - The recent emergence of the COVID-19 pandemic has contributed to the drastic production and use of healthcare and personal protective equipment,...     

Functional autoregressive forecasting of long-term seabed evolution

There is a need for decadal predictions of the seabed evolution, for example to inform resurvey strategies when maintaining navigation channels. The understanding of the physical processes involved in morphological evolution, and the viability of process models to accurately model evolution over these time scales, are currently limited. As a result, statistical approaches are used to supply long-term forecasts. In this paper, we introduce a novel statistical approach for this problem: the autoregressive Hilbertian model (ARH). This model naturally assesses the time evolution of spatially-distributed measurements. We apply the technique to a coastal area in the East Anglian coast over the period 1846 to 2002, and compare with two other statistical methods used recently for seabed prediction: the autoregressive model and the EOF model. We evaluate the performance of the three methods by comparing observations and predictions for 2002. The ARH model enables a reduction of 10% of the root mean squared errors. Finally, we compute the variability in the predictions related to time sampling using the jackknife, a method that uses subsamples to quantify uncertainties.     

Landfill leachate-induced toxicity in mice

Microbial, plant and studies in aquatic animals have shown that landfill leachate is toxic. However, more information about its effects in terrestrial animals is required. As a part of ongoing research into the toxic effects of landfill leachate in Nigeria, we evaluated the acute effects of raw and simulated leachates from Abadina, Orita-Aperin and Oworonsoki dump sites, all in Southwest Nigeria, in mice. Raw leachates were obtained directly from the dumps while the simulated leachates were obtained from the solid wastes in the laboratory by using the ASTM method. The samples were designated Abadina raw leachate (ARL), Orita-Aperin raw leachate (OARL) and Oworonsoki raw leachate (OWRL); and Abadina simulated leachate (ASL), Orita-Aperin simulated leachate (OASL) and Oworonsoki simulated leachate (OWSL). Their physico-chemical properties were determined in accordance with standard analytical methods. Young male mice (12-15 wk) weighing 24-31 g were exposed to 1%, 5%, 10%, 25%, 50% and 100% concentrations of each test samples for 5 consecutive days and were observed for a period of 96 h for toxic response. Mortality recorded at different times for each sample at the various concentrations was mostly within the last 48 h of the exposure period. The LC50 obtained are 100% for both ARL and OARL, and 50% for OWRL; and 83.50% and 50% for ASL and OWSL, respectively. It was indeterminate for OASL. Apart from this, other toxic effects like weight loss, sluggishness, loss of hair and reduced food intake were observed. The investigated samples were ranked as OWRL > OWSL > ASL > OARL > ARL > OASL. The observed effects were due to the toxic constituents present in the leachate samples. This suggests that the mixtures have the potential to cause harmful effect to public health and our environment through seepage into ground or surface water.