Contamination of the Sandstone Aquifer of Prince Edward Island, Canada by Aldicarb and Nitrogen Residues

Abstract

Prince Edward Island is wholly dependent upon ground water from a highly permeable fractured sandstone aquifer for all industrial, domestic, agricultural, and potable uses. The contamination of this aquifer by agricultural residues, principally aldicarb and nitrate, has caused concern among Islanders. Ground water quality was monitored between 1985 and 1988 beneath two potato fields to which aldicarb (Temik) was applied at planting once or twice between 1983 and 1986. In May of 1988,12 percent of 48 monitoring well samples exceeded the drinking water guideline of 9μg/L for total aldicarb. Furthermore 32 percent of all samples exceeded the nitrate guideline of 10 mg/L. Aldicarb persistence appears related to its application at planting when soil temperatures are low and recharge is high and to the inhibiting pH effect that ammonium (from fertilizers and soil organic nitrogen) oxidation has on its degradation. Therefore, based on the research of others, it is recommended that aldicarb be applied at plant emergence when degradation is more rapid and recharge is lower.

Regression Models for Estimating Concentrations of Atrazine plus Deethylatrazine in Shallow Groundwater in Agricultural Areas of the United States

“…Consequently, if all other factors are held constant, atrazine and DEA are more likely to persist long enough to reach groundwater if the atrazine is applied in cool climates or at cool times of the year than if the herbicide is applied in warm climates or during warm seasons. Several authors have suggested that the effect of temperature may be reinforced by the effects of recharge because cold seasons often coincide with periods of greater precipitation than warm seasons (e.g., Wyman et al, 1985; Jones et al, 1986; Priddle et al, 1989, 1992; Pickett et al, 1990; Porter et al, 1990; Traub‐Eberhard et al, 1994). However, the present study did not observe a statistically significant interaction between airtemp and recharge ( p = 0.94), indicating that the effects of temperature on atrazine residue concentrations in groundwater are independent of the amount of recharge received.…”

Controls on Nitrate Loading and Implications for BMPs Under Intensive Potato Production Systems in Prince Edward Island, Canada

“…This range of velocities is also applicable to the flow in the unsaturated zone, for the case when portions of the fractures existing in the unsaturated zone become temporarily saturated, as may occur after a significant rainfall or snowmelt event. The number of fractures and their apertures generally decrease with depth, implicitly leading to a decrease of hydraulic conductivity and to the conclusion that the shallow, most active portion of the aquifer is also the most easily contaminated (Francis and Gale ; Priddle et al ).…”

Favorable and unfavorable attachment of colloids in a discrete sandstone fracture

“…In the United States the proportion of the population that relies on groundwater for domestic purposes rises to 51%, with rural areas again being more reliant at 63% of total water use [2]. Sandstone aquifers are a widespread source of drinking water; for example, the province of Prince Edward Island is completely reliant on a fractured sandstone aquifer for all of their water supply [3]. In many locations, especially in rural areas, septic tanks and underground storage tanks are commonly used alongside drinking water wells.…”

“…Sandstone aquifers are a common drinking water source in Canada and around the world. For example, the province of Prince Edward Island (PEI) is completely dependent on a highly permeable fractured sandstone aquifer for all of their industrial, domestic, agricultural, and potable uses [3]. Sandstone aquifers transmit most of their water through joints, fractures, and bedding planes [8].…”