All pesticides are toxic to some degree. This means they can pose some risk to you, to your children, pets, and to any wildlife that venture onto your lawn, especially if these chemicals are overused or carelessly applied. Pesticides can also kill earthworms and other beneficial organisms, disrupting the ecological balance of your lawn.
Loose or sagging plastic gutters will not drain properly, and this may cause their contents to overflow. As a temporary measure, hammer in a wooden wedge between each bracket and the gutter to hold each section in place until you can replace it.