Asian Journal of Environment & Ecology

Most of the cities in the world, a solid waste recycling process is a part of the effective and sustainable waste management system. Although the local authorities ignore the recyclable solid waste materials during waste management activity, a number of self-waste collectors and dealers have been performing recycling activity as a source of acquirement for long periods of time in Bangladesh. In our present study, a traditional recycling practice of solid waste was executed and analyzed in Sadar Upazila of Noakhali, Bangladesh. This study also identified a complete concatenation from waste collectors to recycling industries in different private sectors. The study revealed that 41% metal, 37% paper, 14% tin and 8% plastic of Sonapur was recycled daily. On the other hand, the study also revealed that 44% metal, 21% paper, 19% tin and 16% plastic of Maijdee was recycled daily. The shop owners were only interested with Recyclable Solid Wastes (RSW). RSW collected by the shop owners including glass, paper, plastic, iron, tin etc. All the recyclable materials were collected and transported in different industries of Dhaka. For new products, those retrieved materials were used as raw materials.

The peoples in Cotonou give themselves to sorting and recycling activities of scrap metal for lack of financial means. The uncontrolled use of this scrap metal has effects on the health of users (waste pickers, sorters, recyclers …). It was to assess the radiological quality and the degrees of dangerousness of this scrap metal waste that we conducted a study on the urban scrap storage site in Cotonou. Thus, this study is a contribution to improving the health of scrap metal collectors, sorters and recyclers in Cotonou.

To achieve this objective, measurements of the dose rates of ionizing radiation from scrap metal were measured using a radiation survey meter. Measurements are made on contact and from a distance. In addition, analyzes of the waste of the powder samples by gamma spectrometry were also carried out.

It emerges from this study that the quantities of ionizing radiation doses vary ranging from 7.14 msv for simple copper to 7.17 msv for iron per year. Thus the quantities of ionizing radiation doses increase with burnt copper 22 msv per year and stainless steel 53 msv per year. These doses are significantly higher than the standard of the dose threshold accepted by the IAEA, which is 100 msv over 5 years for workers or on average 20 msv on contact. Ionizing radiation emitted by scrap metal, engine batteries and battery cells cannot be detected by our survey meter beyond 95 cm. In the case of powder waste, it appears that the powder waste contains radionuclides such as K40, Pb 214 and Ra 226, which give off variable energies and exhibit various activities.

These effective doses being clearly above the thresholds accepted by the IAEA confirms the fact that scrap metal is dangerous to the health of workers.

Acute toxicity effects of ethanol extract of Alchornea cordifolia leaf on Clarias gariepinus fingerlings was investigated over a 96hr exposure period as a potential organic piscicide. A static toxicity bioassay was performed after preliminary trial tests (range-finding test) were conducted. Five hundred (500) post-fingerlings of Clarias gariepinus were distributed randomly in duplicate concentrations. The test fishes were treated with concentrations of 1.31, 1.96, 2.97, 4.45 and 6.67 mg/1 of Alchornea cordifolia. Exposure to the plant toxicant caused visible behavioural changes which include erratic swimming, air gulping, discolouration, loss of body equilibrium, the settlement at the bottom and death. Mortality was recorded in some of the exposed fish while the LC50 lethal concentration of 2.138 mg/1 was established and safe concentration was established as 0.2138 mg/l. There were significant changes (p˃0.0.5) in the water quality parameters except for electrical conductivity, the unstable behaviour of the fish must have been as a result of irritation from the toxicant. Therefore, the use of A. cordifolia in fish harvesting should be regulated and not allowed to gain access unnecessarily into the aquatic ecosystem and regulatory bodies should maintain the safe concentration of 0.2138 mg/l.

The Meghna River is one of the most important rivers in Bangladesh, one of the three rivers, the Ganges delta, and the largest delta in the world in the Bay of Bengal. The water quality of Meghna has become a matter of concern due to serious levels of pollution. The present study was conducted to assess the surface water quality of upstream of the Meghna River using physic-chemical parameters in summer and winter season at five different points. Water quality was evaluated by laboratory analysis considering a total of six water quality parameters, pH, DO, BOD, COD, salinity and TDS and water samples were collected from five stations. The study indicates that some parameters exceed the permissible limit for drinking purpose, it may cause potential threat to the human, but the water of this river is not immediate threat to human or ecosystem.

This paper has been retracted due to complain from the University regarding data protection policy.