Impact of Chemical Fertilizer and Pesticides on Aquatic Microcosms

Abstract

Four commonly used greenhouse chemicals: 10:10:10 Peters fertilizer, two fungicides and an insecticide/nematicide, were analyzed to determine their effects on water quality and productivity. Each of these chemicals in varying concentrations were added to three microcosms and assessed for their impact on pH, total dissolved solids (TDS), specific conductance, and dissolved oxygen, nitrate, ammonia, phosphorous, algae and chlorophyll a. In general, the addition these of chemicals did not affect pH, TDS, specific conductance or the dissolved oxygen. In all microcosms, the addition of fertilizer increased phosphorus, nitrate-N, and ammonia-N concentrations which in turn increased the size of algae communities and chlorophyll-a concentrations. There was a significant correlation between the size of the algae communities and chlorophyll a concentrations in all microcosms. The effect of fungicides and insecticides/nematicides varied among the different chemical concentrations, but in general, there was a reduction in nutrient concentrations with increasing concentrations of the chemicals. But when these chemicals were combined with fertilizer, nutrient concentrations, algae communities and chlorophyll-a exhibited similar increases as the microcosms receiving fertilizer alone. Based on the results of this study, a hydroponic system was designed to reduce the influx of nutrients into receiving fresh water systems.