Battery’s harm to the environment is mainly referring to the pollution happened during manufacturing process and caused by the waste battery. The main pollutants include hazardous heavy metals and the electrolyte of acid, alkali, or organic solution.
Take lead and H2SO4 (sulfuric acid) of the lead-acid battery for example, the lead could be absorbed by the plants from the polluted water system, and then be transferred into human body through foods and accumulate there, do harm to human’s nervous system, digestive system, blood system and bones, lead to anemia and /or some other diseases; H2SO4 would lead to soil deterioration and affect the growth of the plants. 

Cadmium compounds of the Cd/Ni battery could accumulate in plants and aquatic organisms, and be transferred into human body through respiratory tract or digestive tract in the form of polluted air, water or foods. The incubation period of cadmium accumulation in human body could last for 10~30 years, lead to diseases as hypertension, neuralgia, osteoporosis, nephritis, and endocrine dyscrasia, etc. The “Itai-itai Disease”, which had outbroken in Japan before, is in essence a result of cadmium poisoning.

Mercury, contained in zinc manganese battery and alkaline zinc manganese battery, is also a highly toxic metal which could pollute water system, and be transformed into digestible substance as methyl-mercury by the microbes; it would do great harm to human’s brain and kidney, once being absorbed.

Besides, components as ①copper and nickel in the battery, ②alkali in alkaline zinc manganese battery, Cd/Ni battery, MH/Ni battery, and ③organic electrolyte of lithium battery or lithium-ion battery would also lead to environmental pollution.