With the progress of science, the relationship between chemistry and human health is getting closer and closer. The following statements are wrong: (a) sugar, protein and inorganic substances.

B, polyethylene film is non-toxic and can be used as food packaging, so B is correct;

C. From the relationship between elements and human health, it can be known that if the human body is short of iron, it is easy to suffer from iron deficiency anemia, so C is correct;

D, excessive use of chemical fertilizers and pesticides will cause pollution to the environment, so chemical fertilizers and pesticides should be used reasonably, so D is wrong.

So choose D.