Question

observe a river near you. find out about its history . was it in same state many years ago?who is responsible for its current state and why?​

Answer 1

human beings are responsible for this current state at some extent
because:
1)The pollutants that contaminate the quality of water are known as ‘Water Pollutants’such as human excreta, wastes from household kitchens, toxic and radioactive substances, etc. 
2)Most of the water pollution occurs due to wastes released by chemical factories, oil factories or oil spill accidents. Here are the major causes of water pollution.
3)Wastes released from factories are usually toxic, dangerously treated with chemicals and sometimes there are even nuclear wastes disposed of in water such as uranium, radon, etc. Along with this, there are also chemicals released in water after the completion of their use; chemicals such as pesticides and insecticides, soapy water, etc; and these chemicals can be organic or inorganic chemicals.