4. You are investigating the impact of salt accumulation in storm water runoff to a creek. You have measured the salt coming from a parking area adjacent to your sample area at concentration of 0.5 mg/L and at a rate of 12 L/day. Contaminated run-off is also coming from the adjacent road way at a rate of 2 mg/day. The salt measured downstream of your study site has a concentration of 0.25 mg/L and a discharge rate of 12 L/day. You want to know the contribution of salt from re-suspended sediment in the river. If salt has been found to be accumulating in the river at a rate of 7 mg/day, at what rate is suspended sediment introducing additional salt to this system