Explain the management of hazardous wastes.

The management of hazardous wastes: Hazardous-waste management is the collection, treatment, and disposal of waste material that poses a threat to the environment and human health. Hazardous wastes can take the form of solids, liquids, sludge, or contained gases, and they are generated primarily by chemical production, manufacturing, and other industrial activities. Improper hazardous-waste storage or disposal frequently contaminates surface water and groundwater supplies as harmful water pollution and can also be a source of dangerous land pollution. Hazardous waste can be treated by chemical, thermal, biological, and physical methods. Chemical methods include ion exchange, precipitation, oxidation and reduction, and neutralization. Among thermal methods is high-temperature incineration, which not only can detoxify certain organic wastes but also can destroy them. Hazardous waste generated at a particular site often requires transport to an approved treatment, storage, or disposal facility. Because of potential threats to public safety and the environment, transport is given special attention by governmental agencies. Infectious wastes include used bandages, hypodermic needles, and other materials from hospitals or biological research facilities. Radioactive wastes emit ionising energy that can harm living organisms. Because some radioactive materials can persist in the environment for many thousands of years before fully decaying, there is much concern over the control of these wastes. Toxic wastes are poisons, even in very small or trace amounts. They may have acute effects, causing death or violent illness, or they may have chronic effects, slowly causing irreparable harm. Some are carcinogenic, causing cancer after many years of exposure. Others are mutagenic, causing major biological changes in the offspring of exposed humans and wildlife. Reactive wastes are chemically unstable and react violently with air or water. They cause explosions or toxic vapours. Ignitable wastes burn at relatively low temperatures and may cause an immediate fire hazard.

Explain the components of Pond eco-system.

A pond ecosystem refers to the freshwater ecosystem where there are communities of organisms that are dependent on each other and the prevailing water environment for their nutrients and survival. Usually, ponds are shallow (hardly 12 – 15 feet) water bodies in which sunlight can reach to its bottom, permitting the growth of the plants that grow there. The pond ecosystem is a complex interaction between the abiotic and biotic components. Producers: These are the aquatic green plants, which may be divided into two groups. Phytoplanktons: These are microscopic autotrophs, which make solar energy. Ex. Spirogyra , Volvox , Oedogonium . Macrophytes: These are large plants, which make complex food. They are of the following types Submerged plants: These are submerged in water, are submerged plants are Hydrilla and Utricularia . Floating plants: These are floated freely on the water surface are called floating plants Ex. Pistia, Nymphea. Consumers: The consumers are those heterotrophic organisms, which consume producers as food. They are also following types of Primary consumers: These herbivores depend upon autotrophic organisms such as microscopic plant eaters or zooplanktons, Mollusks, Beetles, Cyclops, and Daphnia etc. Decomposers: These include heterotrophic microbes such as bacteria, fungi, which are broken down the organic complex food from stagnant producers and consumers into simple inorganic compounds made possible to the producers. Based on water depth and types of vegetation and animals, there may be three zones in a lake or pond. The different zones are as follows: Littoral zone – It is the shallow water region that is usually occupied by rooted plants. Limnetic-zone - It ranges from the shallow to the depth of effective light penetration and associated organisms are small crustaceans, rotifers, insects, and their larvae and algae. Pro-fundal zone - It is the deep-water part where there is no effective light penetration. The associated organism are mussels, crabs, worms etc.