Summary of the 1992 South Carolina Stored Pesticide Waste Survey

Survey conducted in 1992 by P.M. Horton, R. Poling and R.G. Bellinger
Funding provided by SC DHEC

Methodology

The population for the statewide stored waste pesticide survey was identified as all individuals who were currently holding private applicator licenses in South Carolina. The Clemson University Department of Fertilizer and Pesticide Control (now Clemson University Department of Pesticide Regulation) database for certified private applicators was used to establish the frame for the population. Approximately 10,000 names were included in the database.

Names of 374 individuals were randomly sampled from the database using a sampling formula that provides a confidence level of 95% and a margin of error of +/- 5% when applying the sample results back to the population.

A mail survey instrument was developed by the researchers to collect information from the randomly selected sample related to stored waste pesticide. The instrument was reviewed by a panel of experts at Clemson University to insure both content and face validity. A pilot test of the instrument was conducted using 292 randomly selected certified private applicators from Sumter County who had not been selected to participate in the statewide survey. The survey instrument was modified slightly as a result of information collected through the pilot test.

Anonymity of respondents was guaranteed through the use of a "returned" card, a postcard that was sent back by respondents separately from the completed survey instrument indicating that the individual had completed and returned the survey instrument. There was no indication of the identity of the respondent on the survey. A packet containing the survey instrument, "returned" card and a cover letter was mailed to the 374 individuals sampled on July 31,1992. A reminder postcard was sent to nonrespondents after 7 days. After an additional 14 days, a second packet containing another survey instrument, "returned" card and cover letter was sent to those who had yet to respond. A final postcard reminder was sent to those who had not responded after another 7 days had passed.

A total of 272 completed surveys were returned for a 72.7% response rate. One survey was not usable, resulting in a data sample of 271 or 72.5% usable response rate.

Notable Findings

When asked whether or not they farmed or had ever farmed, 77.1% of the respondents said that they farmed or had farmed.

The types of farming activity reported were 68% row crops (cotton, tobacco, soybeans, corn, etc), 5% forest products, 8% ornamental /nurseries, 5% livestock, 8% homeowner.

Fourteen percent (14%) of those responding indicated that they had waste pesticides or pesticide containers that they wished to dispose of in an environmentally responsible manner. Six and three tenths percent (6.3%) of respondents reported having solid waste pesticides. Eleven and eight tenths percent (11.8°10) reported having liquid waste pesticides.

When asked why they had waste pesticides the following responses were given: 18% bought too much, 13% changed crops, 16% no longer farmed, 16% bought newer products, 13% had the products on hand when the products became illegal to use, and 5% inherited the products.

A total of 9,644.5 pounds of waste solid pesticides was reported. This represents a median* amount of 255 pounds of solid waste pesticides (range: 2 - 5,856 pounds) per individual reporting having solid wastes. Those reporting having liquid wastes reported a total of 2,034.9 gallons of pesticides or containers. This translates into a median* amount of 8.0 gallons of liquid waste pesticides (range: .13 - 865 gallons) per individual with such pesticides.
 
* The median was used as a representative measure of central tendency for the results in this study due to the skewed distribution of the data which would make the use of the mean value oversensitive to the presence of extremely high values reported by a few individuals. The median represents the value in the distribution where fifty percent of the values are above it and fifty percent are below it.

Of the 9,644.5 pounds of solid waste pesticides reported, 3919.5 pounds (40.6%) were known pesticides. The identity of the remaining 5725 pounds (59.4%) was unknown by those reporting having solid waste pesticides.

Respondents were able to identify 1533.8 gallons (75.4%) of the reported liquid waste pesticides. The remaining 501.1 gallons (24.6%) of liquid wastes were not identifiable.

The uses of the pesticides, the reasons for having the waste pesticides, and a breakdown of the types and conditions of containers reported are shown in the charts included in this report.

Estimates and General Conclusions

Based upon the information reported in this survey, the following estimates might be made. There are approximately 24,500 individuals in SC who report farming as a major part of their livelihood. Applying the percentages collected in this survey one can estimate that about 3430 of these farmers have waste pesticides with 1544 holding solid waste pesticides and 2891 having liquid waste pesticides. (Note that some of the 3430 have both solid and liquid wastes).

From this we can estimate that these farmers have approximately 867,728 pounds of solid waste pesticide, of which 40.6% is of known constituents, and 183,277 gallons of liquid waste pesticide with 75% of this quantity of known constituents.

The significance of the known versus the unknown is that the handling and disposal of the knowns is much simplified. The unknowns are generally older products which must be analyzed before they can be handled or disposed of. The analysis of these products adds significantly to the cost of disposal.

Container condition must also be considered and the survey indicates that for the solid containers, 35% are in good condition, 6% are fair and 59% are poor. For the liquids, 73% are good, 25% fair and 2% good.

Based on all of this we can estimate with fair accuracy that we have from 50, 000 to 400,000 pounds of solid agricultural waste with 41% known, and from 25,000 to 200,000 gallons of liquid ag. pesticide waste with 75% known. The average cost of disposal of known pesticide wastes is $4.00/ pound for solid, and $7.00/gallon for liquids.

Keep in mind that the above figures relate only to on-farm agricultural pesticides. Our best guess, based on a national survey conducted in 1992, is that there are at least an equal amount of waste household pesticides, equal in hazard and .toxicity, stored within homes in South Carolina. Any effort directed towards solving the waste pesticide problem in SC must address these household wastes as well.