மறுசுழற்சி & கழிவு மேலாண்மையில் முன்னேற்றங்கள்

Invasive species are considered as one of the most environmental challenges of the 21st century. They constitute the second cause of biodiversity loss and lead to high economic disruption and public health. Despite significant, financial and human investments made by countries and world conservation of biodiversity agencies, there are not strategies that lead to appropriate measures for sustainable management and control. The objective of this study is to assess the state of knowledge on invasive plants in West Africa and to promote knowledge and exchange information. It contributes also to establish in Western African region, a coordinated early warning system through a network of intervention. The paper discusses concepts and bio-ecology of invasive plants, gives precise indications on their diversity and distribution. To achieve the objectives, a literature review was carried out to collect data on invasive species from Western African countries. Therefore, different information sources included floras, database and collection were consulted. The results how that in West Africa, the information collected on invasive plants indicate that 113 invasive species are reported, distributed in 94 genera and 43 families. The most represented families are Poaceae (17 species) and Leguminosae (16 species). They are followed by Cyperaceae (9 species) and Asteraceae (6 species). Euphorbiaceae, Solanaceae and Nympheaceae have 4 species each one. The most common invasive species in West African countries are present in, at least, eight countries. They are: Chromolaena odorata, Eichhornia crassipes, Salvinia molesta, Typha domingensis and Pistia stratiotes. Depending on data availability, the presence and importance of invasive plants vary from one country to another. It must be noticed that there are few data related to Cape Verde, Guinea Bissau and Nigeria. Recommendations were formulated to improve knowledge and sustainable management of invasive plants in West Africa. The expected results of this work should improve the understanding of issues related to invasive species at national and regional levels

Clay bricks are more popular in building constructions than the cement/concrete bricks because of eco-friendly and low cost. These bricks have been made from clay, since they found. However, the quality of the bricks can be upgraded by doping with the agricultural natural waste materials. Rice husk (RH), is a most common and hugely abundant wastes that consist of SiO2 percentage is RHA. In the present study, eight sets of brick were manufactured and each set consists of three bricks. These bricks were doped with RHA of ratio 0 to 30% of the total weight of mixture with a step of 5%. These bricks were allowed to dry for 3 days and fired in the brick kiln, which the traditional method is still used to burn bricks in Sri Lanka. The physical and mechanical properties of the burnt bricks were tested and compared with Sri Lankan Standard Specifications (S.L.S) as well as the British Standard Specifications (B.S.S) and compared with the commercially available brick made purely from clay. The bricks doped with RHA are obviously superior to the commercially available brick in the Eastern region of Sri Lanka. However, the brick doped with 5% RHA has higher compressibility of 3.7 N.mm-2 and the water absorption of 15.8% that satisfy the S.L.S and B.S.S.

Bio-medical waste (BMW) although comprises a small segment of total municipal waste generated, needs special handling and treatment due to its highly toxic contents, besides being infectious. Cities face serious problems in managing waste in general and it is more important to address issues concerning specific streams of waste. If not managed properly, toxic wastes like biomedical waste, electronic waste can contaminate the municipal waste causing serious implications on public health and environment. The Ministry of Environment and Forests (MoEF) in 2011 indicated that 13,037 healthcare facilities in the country have been found to be in violation of BMW generation and disposal rules 1998. Lately, Bangalore city has been emerging as the centre for medical tourism with its professional experts, technological sophistication in health care services. Although the Central Pollution Control Board has come up with the ‘Bio-medical Waste-Handling and Management Rules-1998’ again amended in 2000 by the MoEF, problems concerning proper management remains. This paper aims at identifying issues related to BMW in ward 128 of Bangalore city, Southern India. Questionnaires and Checklists were developed and survey of all the prevailing 27 medical institutions was carried out in the ward. Besides, the role of formal recyclers and their challenges was also considered. Issues like lack of comprehensive data, dumping of medical waste with municipal garbage, poor awareness among the hospital staff were identified indicating the need for a comprehensive research study to be undertaken at a city level.