ENVIRONMENTAL PROTECTION AGENCY OFFICE OF ENFORCEMENT REVIEW AND EVALUATION REPORT ON PESTICIDE POLLUTION OF THE LOWER COLORADO RIVER, PARKER DAM TO THE SOUTHERLY INTERNATIONAL BOUNDARY Prepared by National Field Investigations Center-Denver Denver, Colorado May 1973 ------- ENVIRONMENTAL PROTECTION AGENCY OFFICE OF ENFORCEMENT REVIEW AND EVALUATION REPORT ON PESTICIDE POLLUTION O.F THE LOWER COLORADO RIVER, PARKER DAM TO THE SOUTHERLY INTERNATIONAL BOUNDARY Prepared by National Field Investigations Center-Denver Denver, Colorado May 1973 ------- LIST OF ABBREVIATIONS In the interest of brevity and ease of reading, the following abbreviations are used frequently in this report: OP - Organo-phosphorus compound or pesticide - singular arid plural. OC - Chlorinated hydrocarbon or organo-chlorine compound or pesticide — singular and plural. UR - Urethane or carbamate compound or pesticide - singular and plural. H - Herbicide - singular and plural. ------- 2 I. INTRODUCTION Five major agricultural areas are located immediately adjacent to the Lower Colorado River, in the reach which forms the Arizona-California and Arizona-Baja California borders. The mild climate and constantly available irrigation water supply lead to year-around cropping of these lands. Production of two or three high—value crops per year, together with climatic conditions which are very favorable to insect populations and weed growths cause the areas to be subjected to extremely intensive applications of pesticides. The highly developed irrigation drainage systems are suspect of providing direct return of pesticides to the Colorado River. Investigations carried out by the Colorado River Basin Water Quality Control Project staff in 1963 and 1968 showed that the inter—state and international waters of the Colorado River downstream of Parker Dam were polluted by agricultural chemicals including pesticides. These waters are subject to the full range of uses, including domestic consumption, in Yuma, Arizona, in at least 11 communities in Southern California, and by communities in northern Mexico. Fish taken from these waters were found to contain very high concentrations of DDT and its metabolic products. Brain tissue from distressed fish taken from Lower Colorado River waters during 1968 showed cholenesterase inhibition as high as 35 percent which is indicative of a high degree of stress. Virtually no water quality data are available to indicate trends in these conditions subsequent to the 1968 investigation. ------- 3 This report summarizes the findings of the earlier field investi- gations, relates the information obtained through recent reconnaissance activities, and suggests legal and technical approaches to control of pesticide pollution in the subject waters. ------- 4 II. SUMMARY AND CONCLUSIONS Pesticide pollution of the Colorado River, in the Yuma, Arizona, area, was shown during 1966 and 1968 to constitute a serious hazard to the fishery and to domestic and recreational users of these waters in the United States and in Mexico. In addition to the hazards shown by the 1968 investigation, to exist in the immediate Yuma area and in Mexico, three major irrigation drains discharge to the Colorado River upstream of Imperial Dam. Pesticides contained in discharges from these drains are available for transport, via the All-American Canal, to domestic water users in twelve communities in Arizona and California. Subsequent to 1968, water quality data pertaining to the subject waters have not included information sufficient to permit evaluation of the pesticide pollution problem. Within the five major irrigated areas, between Parker Dam and the Northerly International Boundary, total irrigated acreage and total applications of pesticides have increased since 1968. Use of the long-lived organo-chiorine compounds has re- mained nearly constant at approximately one million pounds per year, while use of the shorter-lived, highly toxic organo-phosphorus compounds has increased 18-fold to nearly 1.8 million pounds per year. More than 5 million pounds of these materials were applied to the croplands, within the five areas, during 1972. These statistics indicate that the hazards, documented and implicit, have not diminished and have probably become more severe. ------- 5 Peak hazard to water users is believed to occur during the June- October cotton growing season. More than one—half of the total yearly organo-chiorine and organo-phosphorus applIcations are made during this one-third of the year. The ways by which pesticides reach the Colorado River are believed to involve: (1) runoff from fields during infrequent summer storms, (2) drifting and overspray during applications, (3) sub—surface drain- age and tail water from irrigated fields, (4) dumping of excess mixes and clean-up of application equipment along and into waterways, and (5) direct application. Control means and procedures, legal and technical, are available through which pollution of the Colorado River by pesticides can be minimized. The technical measures include improved farming practices, optimized drainage of irrigated croplands, control of tail water, judicious selection of the pesticides to be employed, elimination of dumping and overspray, biological controls, integrated controls, and treatment of drainage to remove pesticides. Legal approaches include improvement of State statutes regulating pesticide use; application of the National Pollutant Discharge Elimination System dscharge permt requirements and other sanctions under the Federal Water Pollution Control Act Amendments of 1972, such as, the toxic substances provision and the emergency powers clause; punitive action through the Rivers and Harbors Act of 1899 or the Federal Common Law of Nuisance; legal defi- nition of responsibility, by irrigation districts, for the quality of discharges from district owned and operated drains. ------- 6 A thorough documentation of the present pesticide pollution situation within the Parker Dam—Southerly International Boundary reach is needed to provide the evidence and emphasis which can be translated into effec- tive control of sources. ------- 7 II I. DESCRIPTION OF AREA The Lower Colorado River valley, downstream from Parker Dam is characterized by broad flat flood plains of alluvium overlain by evenly sorted Aeoflan soil. The soil is readily drained and is exceptionally well suited to irrigated farming. The climate within the area is arid, with rainfall of less than five inches and evaporation exceeding six feet, annually. Runoff to this reach of the Colorado River occurs as a result of infrequent thunderstorms and irrigation return flows. Water quality, within this reach, degrades seriously because of withdrawals and irrigation return flows. For example, mean total dissolved solids concentrations increase from approximately 720 mg/i at Parker Dam to 1,590 mg/i at the Northerly International Boundary. The mean temperature of the stream ranges from 18°C at Parker Dam to 21°C at the Northerly International Boundary. The pH varies from 7.7 to 8.1. Throughout the reach, the stream is invariably supersaturated with dissolved oxygen. Nutrients are in abundant supply, supporting nuisance growths of algae and an excellent fishery. The five major irrigated areas IFigure 1] are the Colorado River Indian Reservation (CRIR), Palo Verde Irrigation District, Weliton-Mohawk Irrigation District, Vuma Project-Valley Division, and Yuma Project- Reservation Division. Each area is drained by one or more open drains, of which all but one discharge to the Colorado River. In addition to the five listed areas, the All-American Canal conveys water into the Imperial Valley for domestic and agricultural use. There is no return flow from the Imperial Valley to the Colorado River. [ The diversions, canals, irrigated areas, and drains are shown schematically in Figure 2.] ------- / >. _.,-,-—I---- 7 II’ l — ( I E C E N D .‘ / PIOI r . . .“ I) I t’k,Colorodo L ( RIVIf AQuOduCt t’ninninn niurn •tinii .i 1 PARKEROAM ) I • L U L U fl PS LI U fl I V L fl I U I M ri Mi.5l0.2 Gu in 5I ji ii 2. RESERVATION GogingS1 ø hi Tfl IP T Section 38 HESL1OGATE P )CK U I I R I %x I orkir DAM 3. WEITON MOHAWK PROJECT Ui.524.S 4. YVMA PROJECT VALLEY Coliforneo LeweeJ- DIVISION 8r : ______________ —-—-- . -- . YUMA PROJECT RESERVATION no Ltvee DIVISION ALO VEPDE\ - N - ‘(z 1D(VEF?SlON DAM I M.5688 ‘ ;j’Scclion29 2 cec ’ ion a Il h JEhr.nb.r9 I ( — - ________ ______ _____ _____ ______ ___ Polo Vsrde Ferry Mi. 596.2 %\ \ Oxbow LoU. i fl 3 N I 0 ,t(oll Oroin 04.5 \ N . 1_ oY _ ’ \ ; Section 2 GoQing Stotipn below Cibofo Volley / Ruin US8.R) i’ I / Mi6 19.9 , Lighthouse . S ,clicw i l7 ‘ Rock 4 / W•stvnorsior d • . Section Sect icri 6 I, _________— Gcginq 5f f,r — __— . . 7 ’ ) J Wily SENATOR WASH. DAM J .. . . Siphon Drop .-. -. - 1’ Stotion 8I0 — ’ . \ !MPERML .-OAM - I - r i) M 6572 3 mpenol b Section 10 -S Section I S ‘ TEXAS HILL t AL ElCinfro ills ______ &— A - . MsQiryC4 l L -— Luis e• so i,; ) .Y c? n2 -S / \ y - SO,4j 4l s r i ? . ‘I ,-:f Q, . ;& F L’ - Figure 1. Areas of Pesticide Application ------- ‘PARKER DA lI PALO VERDE O 1VERSION DA l I ’ PALO VERDE IRRIGATION DISTRICT PALO VERDE OUTFALL DRA IMPERIAL VALLET RESERVATION DIVISION IIORTWERN BOIJ I I DART MQRELOS DAM’ •WELTON MOHAWK PROJECT DRAIN GULF OF CA Li F DRill A Figure 2. Schematic of Irrigation Diversions and Drains-tower Colorado River ‘HEADGATE ROCK DAM COLORADO RIVER INDIAN RESERVATION .CRIR UPPER MAIN DRAIN i s a CRIR -LOWER MAIM DRAIN AL DAM MODE 1 VILLE T DIV ISION ALAMO CANAL MODE 3 NOT TO SCALE — S ------- 8 Streamflow in the Colorado River main stem is highly regulated. Delivery schedules, both to the .Anierican users previously listed and to the users in Mexico, cause rapid and severe changes in stream stage, velocity, dilution capacity, and quality. The waters within the subject reach, the California service area, and in Mexico, are subject to the full range of uses, including domestic water supply, primary and secon- dary contact recreation, fish propagation, industrial, and agricultural. ------- 9 IV. AGRICULTURAL PRACTICES A. General Climatological conditions, excellent soil, and constantly available water supply combine to create ideal growing conditions. Most of the lands are cropped on a year—around basis. Major crops grown are alfalfa, cotton, wheat, barley, corn, sorghum, lettuce, melons, citrus, and grasses. Many lesser crops, including green vegetables, sugar beets, and nuts, are also grown. Flood irrigation is widely practiced; however, alfalfa and grasses are occasionally spray-irrigated. The lands are all drained by open drains to the Colorado River, but major differences exist in the drain- age systems. Some lands are underlain by highly developed tile drainage systems, some are drained by pumped wells, while others depend on percolation and lateral movement to drains and streams. Lands drained by tile systems are usually well leached, and the return flows percolate quickly to the tiles, thence to the open drains. Lands that are de- pendent upon natural drainage are usually less well—leached and can, in fact, store salts from the applied irrigation water, and tend to return drainage of poorer quality to the open drains. Most practitioners of flood irrigation direct tail water (excess water reaching the down - slope end of the furrows) to the nearest surface drain. The tail water can carry large quantities of chemical residue, crystalized salts, and debris, which has been picked up in the initial surge down the furrow. B. Pesticide Applications Except for similar areas in the Lmperial arid Coachella Valleys, probably no other area on earth ! subjected to such intense applications ------- 10 of agricultural chemicals. Fertilizers are applied primarily by ground rigs, while pesticides, including herbicides, are applied by means of both ground and aerial equipment. In terms of water pollution, pesti- cide applications upon lettuce and cotton are of particular concern. Repeated and heavy applications of highly toxic chemicals are necessary to control the variety of pests which plague these crops. Applications upon other crops vary widely according to the form arid extent of infesta- tions experienced from year to year. In recent years, some shift toward a preponderant use of OP and UR, as opposed to OC use, is evident. This shift has been brought about by: (1) the banning of DDT and related persistent compounds, (2) the need for more toxic substances to overcome tolerances attained by some pests, and (3) the widespread belief by farmers, distributors, and applicators that the shorter-lived OP are a lesser hazard to the envi ronment. OC use remains significant, particularly upon cotton. The total pesticides and herbicides applied to croplands within the five subject areas during 1972 are summarized as follows: Class of Pounds Applied Compound During 1972 Organo-phosphorus 1 ,794,000 Organo-chlorine 940,000 OP-OC combinations 192,000 Carbamates 1,106,000 Herbicides 1,169,000 Total applications in 1972 5,201,000 ------- 11 By comparison, in 1968 approximately 1,000,000 lbs of OC and 100,000 lbs of OP were applied to the same areas. Use of UR was essentially negligible at that time. Thus, use of OC has remained nearly constant; use of OP has increased 18-fold; and UR use has reached proportions comparable to total pesticide use in 1968. The intensity of application, and thus the hazard to Colorado River water users, reaches a peak during the four months of the cotton growing season. Estimated use during the 1972 cotton season and the percentage of the total application for the year are summarized as follows: Class of Pounds Applied Percent of Compound July-Oct 1972 1972 Total Organo-phosphorus 1 ,045,000 58.2 Organo-chlorine 506,000 53.8 Carbamates 455,00O 41.1 Herbicides 1i66,000 39.9 2,472,000 47.5 It is readily seen, from this summary, that more than one—half of the OP and CC applications occur during one-third of the year. From the water pollution control standpoint, this fact takes on added significance because water applications and return flows also peak during this period. Transport of pesticide residues to open drains and the receiving stream is thus enhanced. ------- V. THE LOWER COLORADO RIVER PESTICIDE POLLUTION PROBLEM A. ys by Which Pesticides Enter the Stream Pesticides find their way into open drains, canals, and streams in several ways. These are believed to involve: (1) runoff from fields during infrequent summer storms, (2) drifting and overspray during applications to crops near canals, drains, and streams, (3) sub—surface drainage and tail water from irrigated fields, (14) dump- ing of excess mixes and the cleanup of application equipment in water- ways, and (5) direct application to control aquatic weeds, rough fish, and aquatic insect pests. Storm runoff can be discounted as a major vehicle for pesticide pollution within the subject reach, because of the infrequency of runoff events. The other listed means by which pesticide pollution is thought to occur are subject to viable controls, both legal and tech- nical in nature. These control procedures and methods are discussed later in this report. B. The Hazards Associated with Pesticide Pollution Organo-chiorine pesticides are highly persistent in the envi ronment. For example, the half—life (time required for one-half of the amount originally present to degrade) of chlordane is on the order of four years. These compounds are toxic to fish and to warm-blooded animals, and tend to concentrate through the aquatic food chains. When ingested in sub-lethal quantities, these compounds are stored in the fat and organs of animals, including humans. Thus stored, they become available ------- 13 in higher concentrations when fat is used during stress or low food intake. The OC have been associated with many diverse damages to the aquatic environment and have become ubiquitous in streams and oceans. Organo-phosphorus compounds are related to and, in some cases, derived from the war gases. In general , they are much more toxic and much less persistent in the environment than are the OC. Their half- lives are generally in the range of a few weeks or months. Their ex- treme toxicity is attained through chemical inhibition of the enzyme acetyicholinesterase in the nervous systems of animals. Certain of these compounds are so highly toxic that skin contact, inhalation, or ingestion of very minor amounts can bring on nervous collapse within seconds and death within a few minutes. Minute amounts of these com- pounds in a stream can produce massive fish kills. The hazards to domestic water supplies and to waters used for contact recreation are obvious. The effects of chronic sub-lethal doses of these compounds on fish and warm-blooded animals has been the subject of much research, though producing few applicable findings. The carbamates are also highly toxic, but since they have extremely short half-lives, they are generally considered a lesser hazard than OC and OP. Herbicides are formulated to kill or retard growth of plants. They are, however, toxic to animals in high concentrations. In the subject areas of the Lower Colorado River Basin, a substan- tial increase in the use of OP compounds has taken place in the five- year period prior to 1973, although OC remain extensively used on cotton, lettuce, and citrus. in terms of hazards to users of Lower Colorado ------- River waters, employment of the longer-lived OC remains at levels that can be expected to yield concentrations in water and in fish similar to those reported in 1968. Moreover, use of a particularly toxic OC, Toxaphene, has increased since 1968. As indicated earlier, use of the shorter-lived OP has increased 18-fold since the 1968 in- vestigation. This increase represents an unknown degree of hazard, but one which has not diminished and which deserves careful considera- tion and analysis. Water quality data collected within the subject area since 1968 do not enable evaluation of recent pesticide pollution cond I t ions. C. Previous Studies During the fall and winter of 1963—1964, the Colorado River Basin Water Quality Control Project (PHS-DWSPC) carried out a limited evalu- ation of pesticide concentrations in irrigation return flows. The primary thrust of the effort was toward development of sampling and analytical techniques. The work was discontinued prior to completion. Alarmed by increasingly frequent fish kills, during the 1966-1967 period, the Arizona Game and Fish Department analyzed samples of flesh and viscera from fish taken from waters of the Colorado River near Imperial Dam. These samples were found to contain very high concentra- tions of DDT and other OC compounds. One fish sample from Mittry Lake was found to contain 92.5 parts per million IDE, a decomposition pro- duct of DDT. Another sample obtained from the Yuma Project-Valley Division main drain contained 36.8 ppm Toxaphene. ------- 15 In 1968, the Colorado Project (FWPCA) again initiated limited studies of pesticide concentrations in the Colorado River at the Northerly International Boundary; the Yuma Project-Valley Division Main Drain, near San Luis, Arizona/Sonora; and at the intake of the Vuma, Arizona, Municipal Water Treatment Plant. This study was seriously impaired by the limited number of samples that could be analyzed employing techniques and equipment then available. Never- theless, high concentrations of pesticides were measured. Azodrin, Toxaphene, and Parathion were recovered in almost every sample analyzed. More than 60 percent of the water and carbon-adsorption samples from the three points exceeded the NTAC* Water Quality Criteria for fresh water organisms. Numbers and types of samples exceeding the criteria are summarized as follows: Liquid Composite Carbon-Adsorp— Total Samples tion Samples Percent Samples Exceeding Exceeding Exceeding Analyzed Criteria Criteria — Criteria Vuma Water Treatment Plant intake 23 4 5 39 Colorado R at Northerly Intl Boundary 26 7 6 50 Vuma Proj Main Drain at Southerly Intl. Boundary 22 8 100 [ Average, maximum, and minimum concentrations of total organo-phosphorus and organo-chlorine pesticides and the sums of the quantities determined during this survey are presented in Table I.] * Acronym for the National Technical Advisory Committee to the Secretary of the interior. ------- 16 Table I. Summary of Pesticide Concentrations 1968 FWPCA Survey •Carbon Adsorption Columns S tat i on Colorado R at Northerly Intl. Boundary Organo-phosphorus Compounds (ng/F) Avg . Max. Mm . 260 818 Organo-chiori ne Compounds (ng/l) Av Max. Mm . Tot a 1 Insecticides (ng/l) Avg. Max. Mm . 3 1422 1 ,540 65 Yuma Proj Main Drain at Southerly Intl. Boundary 540 976 271 279 1,053 23 819 1,519 244 Colorado R at Yuma Water Treatment Plant Intake 76 314° 9 89 270 0 165 610 19 Composite Water Samples Colorado R at Northerly Intl Boundary 430 3,370 0 145 1,120 0 548 3,370 140 Yuma Proj Main Drain at Southerly Intl. Boundary 260 1,178 0 710 1,850 83 970 2,578 303 Colorado R at Yuma Water Treatment Plant Intake 50 162 722 218 1,519 0 114 200 0 232 1,519 10 ------- For the past ten years, fish kills have been a characteristic of the Colorado River within the subject reach. Many of the kills have been associated with pesticides. During the 1968 survey, four fish kills occurred, afl of which were associated with high concentrations of pesticides in the waters in which the kills occurred. The study showed that a serious hazard to the fishery and to the domestic and recreational water users, in the Yunia, Arizona, area and in Mexico, existed during the period of the investigation. 17 ------- 18 VI , LEGAL AND TECHNI CAL APPROACHES TO CONTROL OF PESTICIDE POLLUTION IN THE LOWER COLORADO RIVER A. Licensing of Applicators The States of Arizona and California, between which the Lower Colorado River forms the boundary, license and regulate pesticide ap- plicators. The regulatory proviSions deal mainly with labeling and registration of pesticides, safety to handlers and applicators, allowable residues on produce and similar matters. There are no limit- ing concentrations for pesticides in irrigation tail water or drainage that enters surface streams. The regulations provide no buffer zones for the protection of surface waters from drifting of sprayed materials. The dumping of unused mix and cleaning of equipment in irrigation canals or drains which discharge to surface waters and the disposal of pesti- cide containers is not addressed. Similarly 1 discharges of pesticides by formulators are not controlled by the regulations. The statutes do not provide the mechanism for surveillance and enforcement of the regu- lations. In summary, the State pesticide regulatory apparatus in both Arizona and California can be considered to be ineffective in the pre- vention of pollution of surface waters by pesticides. B. Applicable Water Quality Standards Both Arizona and California Water Quality Standards have been ac- cepted by the Secretary of the Interior (EPA Administrator) and are, therefore, Federal Standards. The Standards do not relate to specific discharges and are, thus, virtually useless in the abatement of pollution by pesticides. Extracts of each Standard pertaining to pesticide pollu- tion are as follows: ------- 19 California “3. Biocides Biocide concentrations in Colorado River waters shall be kept below levels which are deleterious to domestic water use and to fish and wildlife.” Arizona “8. Biocides Biocides have been the subject of much discussion in the past 1 and probably will be discussed for many years. Prudent use of biocides has enabled our agricultural industry to provide ample food and fiber products for our high standards of living. Esthetically, we can have better gardens and a more healthful existence because of biocides. Uncontrolled use of biocides is not beneficial, and should not be allowed. Generally speaking, biocides are expensive, and over appl ications are seldom made. Discharges of wastes containing biocides from manufacturing and tank cleaning operations must not be allowed. “More research and study of the cumulative effects of biocides on humans and wildlife must be made, and appropriate safeguards applied as standards for the waters of the State. “Types and effects of biocides are too numerous and varied for tabulation. Further, the intricacies and variations of technical analysis for biocides presently defy the prescription of any one or a few tests for their detection or determination (L 1 ). Bio-assay tests can be used to establish allowable limits for biocides. “Application of biocides in agricultural opera- tions which could result in biocide levels in waters of the State which are deleterious to human, animal, plant or aquatic life shall be subject to abatement. Mere detection of a biocide in the water is not cause for abatement.” ------- 20 C. Federal Water Pollution Control Act Amendments of 1972 A number of legal theories are available to abate pesticide pollu- tion of the Lower Colorado River which is a navigable waterway of the United States and within the jurisdiction of the Federal Water Pollu- tion Control Act (FWPCA) Amendments of 1972. The FWPCA Amendments of 1972 clearly apply to pesticides since the term “pollutant,” among other things, means “industrial, municipal, and agricultural wastes discharged into water.” Tail water, tile drain- age and dumping involve conveyance of pesticides into the waterway through a discrete channel and, therefore, a “point source” as defined by the Act. These discharges contain pollutants which are prohibited by Section 301, unless the discharge is controlled by a National Pollu- tion Discharge Elimination System (NPDES) permit. The permit, if granted, can be so conditioned so that pesticides are removed or otherwise rendered innocuous. In order to meet the intent of Congress in controlling pollution, the “discharge of pollutants” should be given a broad definition. This is somewhat justified since agricultural waste is specifically included within the pollutant definition. Broadly construing the definition of “point source” it can be argued that certain farm areas where highly toxic pesticide concentrates are applied could be considered as point sources just as “concentrated animal feeding operations” are within the point source definition. Portions of an irrigation district would then not only be subject to the effluent requirements of the Act but also the NPDES. ------- 21 The discharge of toxic substances is prohibited by FWPCA Section 301 except as it may be in compliance with Section 307, the toxic substances provision. Section 307 provides for regulations for toxic substances effluent standards, These have not been promulgated. Therefore, any discharge of toxic substances is prohibited until to1 rable effluent standards are established by regulations. As the regulations are adopted, discharge of toxic substances may be permitted only within those limits. Section 307(d) prohibits the violation of any of these standards by any source which would include non-point sources. The L 02(k) immunity from prosecution under either the F 4PCA or the Refuse Act does not apply to Section 307, toxic and pretreatment standards. Therefore, enforcement prerogatives are available to the EPA, under the FWPCA, once the toxic substance list has been promulgated. Congress in- tended, however, that dangerous and toxic substances be abated as soon as possible, even before discharges were limited by the promulgation of standards. In those circumstances EPA may seek injunctive relief against such pollution under Section 5Q1 , Emergency Powers. The Emergency Powers provision provides that “the Administrator, upon receipt of evidence that a pollution source . . . is presenting an imminent and substantial endangerment to the health of persons or to the welfare of persons where such endangerment is to the livelihood of such persons such as inability to market shellfish, may bring suit...” The first category of cases would generally be confined to endangerment of drinking water supplies or threats to humans using designated recrea- tional areas. The second category would include short-term as well as long standing pollution problems where shellfish and other income pro- ducing aquatic life are being substantially affected. ------- 22 This provision is intended to be supplementary to and not a sub- stitute for the regulatory provisions of the Act. However, the Congress recognized that from time-to-time continuous discharges occur which present an imminent and substantial endangerment to persons or to fish and wildlife. It is the Congressional intent that these discharges should be abated through this authority. If certain pesticides can be categorized as “hazardous substances” within the meaning of FWPCA Section 311(a) 1i their discharge may be absolutely prohibited. It is quite doubtful that substances which are registered under the Federal Insecticide, Fungicide, and Rodenticide Act will appear on the hazardous substance list to be promulgated by the Administrator. D. Rivers and Harbors _ Açt of 1899 -Refuse Act The Refuse Act prohibits the discharge without a permit of refuse to the navigable waters of the United States. Courts throughout the country have repeatedly held that the discharge) directly or indirectly, of pollutants such as pesticides is a violation of the Refuse Act. Upon conviction 1 dischargers are subject to civil and criminal penalties under the law. In the irrigation districts adjacent to the Lower Colorado River, irrigation drainage is collected by the districts and discharged to the River. Open drains are subject to dumping of unused pesticide mix, contamination from clean-up of equipment, drift from aerial and ground spray applications, and direct application of chemicals. The discharge of these pesticide laden waters to the Colorado River, a navigable stream, is clearly a violation of the Refuse Act and is sub- ject to criminal or civil penalties. ------- 23 Acceptance of irrigation drainage containing pesticides by irriga- tion districts places each district in the position of knowingly aiding and abetting, authorizing, and instigating a violation of the Refuse Act. Litigation growing out of a comprehensive investigation of pesticide pollution in the Lower Colorado River Basin should charge the farmers and applicators as well as the irrigation district involved. As a result of such a class action, it should become clear to the irrigation districts, the farmers, and the applicators that they must police the application of pesticides within the irrigation district. The Refuse Act, then, is available to abate pesticide pollution of the Lower Colorado River even though the source is indirect in nature. The important point is that pesticide refuse is reaching a navigable waterway which is statutorily prohibited. The 1t02(k) immunity provision of the FWPCA Amendments of 1972 is no defense, since toxic substances are not included in the exclusion. E. Federal Common Law of Nuisance The Federal Common Law of Nuisance could also be utilized to abate pesticide pollution in the Lower Colorado River Basin. In an April 1972 Supreme Court decision, Illinois v. City of Milwaukee , 4ERC 1001, the Court stated that “The application of Federal Common Law (nuisance) to abate a public nuisance in interstate or navigable waters is not in- consistent with the Water Pollution Control Act.” Although the Supreme Court had reference to the FWPCA prior to the October 18, 1972 amendments, the same application could be made to the new law. This “new and im- portant legal remedy” has been used by the Justice Department in a number ------- 2L of cases since the Supreme Court decision. For example, Reserve Mining, Whittaker Corporation, and the City of Memphis, etc. This legal theory could be utilized concurrently with the above mentioned approaches. F. Physical Control Methods Experimental work and research has shown that pollution of surface waters as a result of pesticide applications can be greatly reduced or eliminated through carefully designed drainage systems, carefully con- trolled irrigation practices, and intelligent farming practices. Tail water is excess water that reaches the downslope end of each furrow when flood irrigation is practiced. This tail water is deliber- ately routed to the nearest surface drain. Tail water usually carries large quantities of pesticide residue, crystal ized salts, and debris picked up in the initial surge down the furrow. This source of pollu- tion of surface waters can be minimized or eliminated by the careful application of irrigation water so that no tail water is created or through the disposal of tail water by ponding, evaporation, and infiltra- tion. Much of the irrigated farm land in the Lower Colorado River Basin is drained by deep tile drain systems. Water that percolates past the root zone remains in contact with the soil column of at least 2 meters (6 ft) before reaching the tile drain. Experimental work carried out in the Cochella Valley, in 1968 and 1969, confirms earlier laboratory research which indicates that OC and OP pesticides are adsorbed on soil particles during percolation through the column. Although long-lived OC can subsequently be leached from the soil and continue through the ------- 25 drainage system to reach surface waters, the deep drainage systems are effective in limiting the return of organo-phosphorus compounds. It has further been shown that repeated applications of OP to the same fields results in reduced quantities of residual material reaching deep tile drains. Acclimation and buildup of tolerant soil bacteria which can degrade the short-lived organo-phosphorus compounds is pre- sumed to be the cause of this reduction in yield. Similar investiga- tions have been reported pertaining to carbamates. Recent research discloses that concentrations of organo—phosphorus compounds recovered in tile drains is reduced markedly by increasing the time lapse between irrigation water applications. Thus, careful timing of irrigation applications provides additional possibilities for reduction of pesticide pollution in waters receiving irrigation drainage. it is clear, then, that the judicious selection of pesticides to be used (discussed later herein) , properly designed deep drainage systems, and proper timing of water and pesticide applications can reduce the quantities of pesticides reaching surface streams via irri- gation return drainage. Dumping of unused pesticide mix and the clean-out of pesticide application equipment in irrigation drains and canals is believed to be a major source of pesticide pollution in the Lower Colorado River system. The relatively high concentrations and the slug nature of this mode of pesticide pollution combine to create the potential for serious hazard to human health and welfare, and to aquatic life. No satisfactory method ------- 26 has been employed for prevention of this activity in the Lower Colorado River growing areas. Possibility for control range from elaborate schemes for the tagging of pesticides with dyes or trace elements through equally elaborate schemes of sealing and centralized inspection of application equipment. In any event, State and local governments must adopt statutes which provide for meaningful punitive recourse against dischargers of pesticides and must provide for enforcement of those statutes. Additionally, if irrigation districts are to function as collectors and dischargers of irrigation drainage, they must assume responsibility for quality of the discharge. Irrigation districts have not, at this time, assumed nor been granted the police powers necessary to prevent the introduction of pesticides into the drainage. Enabling legislation is probably necessary. Cotton is the principal crop grown in the Lower Colorado River farming areas, and the susceptibility of cotton to pink boliworm in- festation causes the cotton crop to receive extensive applications of various pesticides. Much work has been done and is being done on methods of control of pink boliworm infestation that would reduce the necessity for application of pesticides. These methods include biological con- trols (discussed later herein) and the interruption of the biological cycle of the pink boliworm. The pink bollworm is particularly vulner- able during larval stage and diapause. interruption of the cycle during these stages can be attained by the burning or shredding of cotton stalk immediately after harvest, deep plowing with a mold board plow at the earliest possible date, filling of cracks and crevices in the soil after plowing, and two irrigations seven to ten days apart shortly ------- 27 after plowing. Early harvesting and clean picking are also extremely important in preventing the emergence of egg laying moths in the following spring. Such control programs might require the impetus of regulatory action. Concerted information programs within irrigation districts could minimize the necessity for applications of hazardous pesticides. Q. Biological Control Biological control holds substantial promise for reduction of pest insect population without application of dangerous chemicals. At the present time three techniques are in the experimental stages. The first of these involves the sterilization of the males of the target speci s such as pink boliworm and screw worm. The sterilized males are broadcast by the millions in infested areas where they mate with normal females which then lay non-viable eggs. This technique has been suc- cessful in the virtual elimination of screw worm populations in the southwest. The second technique involves the enhancement of populations of parasites. Experimental work has shown that wasps can be effective in controlling populations of insects such as the pink bollworm. The female wasp attacks and kills the target organisms and deposits her eggs in the carcass. Upon hatching, the young wasps use the carcass for food and as they reach adulthood, the cycle is repeated. Other than their nuisance factor, wasps are harmless to man. Their prolific nature causes them to be useful in the protection of crops from insect pests. Experimental and test-scale work employing other predator parasite organ- isms is underway at and by a number of research organizations. ------- 28 A third method of biological control, already experiencing success against insect pests on lettuce, kale, and similar crops, is the Bacillus organism. The material applied is a bacterial culture whichis antag- onistic to a specific pest. A brand name now in routine use is Thuricide. H. Chemical Controls Until physical and biological controls can be made completely effec- tive, applications of chemical pesticides wfll continue. The effects on water quality can be minimized through judicious selection of the chemical to be used. OP and UR compounds are readily degraded in the environment while OC are extremely persistent. The acute and chronic toxicity levels of the OP compounds are on the order of 100 to 1,000 times more than for OC. From the farmer’s standpoint, the OP have a more immediate lethal effect on insect pests and are much more expensive than OC, must be applied more often, and are extremely hazardous to use. It follows that, the OC require heavier applications to obtain a kill but have a more lasting effect resulting in fewer applications and lower costs, and are less hazardous in use. Economics and personal safety are much more compelling arguments to the farmer who makes the selection than is water quality. Thus, further regulatory activity may be necessary in order to bring about the use of non-persistent pesticides. I. Removal of Pesticides from Wastewaters Treatment facilities have been developed which are highly effective in the removal of pesticides from effluents discharged by pesticide manufacturers. Although discharges by pesticide formulators are highly ------- 29 irregular both in content and quantity, similar treatment principles must be applied. Treatment of irrigation drainage is equally desirable but would involve an additional requirement, the removal of suspended solids prior to treatment for removal of pesticides. Chlorinated hy- drocarbons have been removed successfully from small streams and lake outlets in Missouri and California using dams constructed in a manner to cause the wastewater to pass through activated carbon. Efficiency of pesticide removal has been reported to be i0 to 50 percent. Some of the systems employ activated carbon cylinders suspended from over- head racks such that waters must pass over and through the cylinders. The latter system has the advantage that cylinders are quickly and easily replaced and the efficiency approaches 60 to 70 percent. Drip basins are a recent innovation more suited to irrigation re- turn flows in which suspended solids would cause the activated carbon flow-through devices to become clogged. This system depends on the property of the newer organo-phosphorus compounds that are readily and quickly hydrolyzed in alkaline waters. In practice, the waste- water is diverted into a lagoon and then is charged with slaked lime, held in suspension by aerators and maintained at a pH of 8.5 to 9.0. After 8 to 12 hours detention, the pesticides are degraded into phos- phorus compounds that form precipitates and settle out or are broken down into harmless components such as methane and CO 2 . Such systems hold promise for economic and efficient removal of organo-phosphorus compounds from irrigation drainage. ------- 30 In the south, clay—lined ditches or channels have proven to be highly effective in the removal of DDT and its metabolites. Although this method holds some promise, efforts should be directed toward elimi- nation of use of chlorinated hydrocarbon pesticides as outlined earlier. J. Coordination of Control Measures As is evident, no one of the control measures discussed herein can solely be expected to eliminate the problem of pesticide pollution of the Lower Colorado River. Very real possibilities do exist for such control through the employment of various combinations thereof. The scenario for successful abatement of the major pesticide pollution pro- blems in the Lower Colorado River Basin should include application of the Federal Water Pollution Control Act Amendments of 1972, Refuse Act and Federal Common Law of Nuisance, efforts through appropriate State agencies to cause effective pesticide pollution control legislation to be enacted, the establishment of routine policing by irrigation dis- tricts to control dumping, the implementation of requirements for deep tile drainage of all irrigated areas, the limitation of compounds applied to those which are non-persistent, the implementation of bio- logical controls and physical controls that disrupt the life cycles of the insecticide pests, and, finally, the treatment of irrigation drain- age from the major irrigated areas. ------- |