Pandas read scientific notation and change

It's hard to say without seeing your data but it seems that problem in your rows that they contain something else except for numbers and 'n/a' values. You could load your dataframe and then convert it to numeric as show in answers for that question. If you have pandas version >= 0.17.0 then you could use following:

df1 = df.apply(pd.to_numeric, args=('coerce',))

Then you could drop row with NA values with dropna or fill them with zeros with fillna