1 

# Ambient Pesticide Monitoring Network:
1992 to 2007

Technical Publication SFWMD 105

Prepared by

Richard J. Pfeuffer

October 2009

South Florida Water Management District West Palm Beach, Florida 334062 Abstract The South Florida Water Management District has collected surface water and sediment samples for analysis of over 80 pesticides since 1992. Resi dues of atrazine and p,p’-DDE are nearly ubiquitous throughout the sampli ng area. Surface water concentrations of
atrazine at nine of the fourteen monito ring locations exhibite d a downward trend and
none of the detected concentrations exceeded es tablished levels of concern. Seventy-five percent of the sampled locations had average se diment residues of p,p’-DDE at levels that may impact sediment-dwelling organisms. Mo nitoring locations with the highest average p,p’-DDE concentrations (based on detected values) and the highest percentage of pesticide detections did not exhibit consistent trends. Some locations exhibited increasing
trends while trends at other locations showed a decrease in concentrations. Additionally, specific location concentrations for ethion, diazinon, and endosulfan documented periods of surface water quality exceedances. Ho wever, product label changes and grower education have substantially contributed to the reduced number of exceedances over time.

Introduction The South Florida Water Management Distri ct (SFWMD) is a regional governmental agency responsible for wate r quality, flood control, wate r supply, and environmental
restoration for 16 counties from Orlando to the Florida Keys. Pesticide monitoring within SFWMD has been ongoing since 1976 (Pfe uffer, 1985) with the routine ambient monitoring program beginning in 1984 (Pfe uffer, 1991). The original monitoring program consisted of 13 locati ons, but overtime it has grown to 34 sampling sites. The current program includes stations designated in the Settlement Agreement, the Lake Okeechobee Operating Permit, and the non-Ever glades Construction Project (non-ECP) permit. The sampling locations are throughout South Florida, and range from Lake Okeechobee through the Everglades Agricu ltural Area (EAA), and down to the Everglades National Park (Figur e 1). Water flow within th e monitoring area is generally
in a north to south direction.

The main areas of agriculture include citrus (Martin/St. Lucie County area, Caloosahatchee River area), sugarcane (EAA) , and the row crop area of South MiamiDade County. Also the coastal urban areas were an additional source of pesticide
residues.

The District's canals and marshes are prot ected under Florida Ad ministrative Code (F.A.C.) Chapter 62-302 as Class III (fis hable and swimmable) surface waters, while Lake Okeechobee and a segment of the Caloos ahatchee River are protected as a Class I drinking water supply. Water Conservation Area 1 (WCA-1 ), which encompasses the
Arthur R. Marshall Loxahatchee Nation W ildlife Refuge and the Everglades National Park are also designated as Outstanding Florida Waters, und er Chapter 62-302, F.A.C., to which anti-degradation standards apply.

The pesticide monitoring program has evolve d over time. Sampling for new pesticides
and from new locations has been added due to increasing concerns over pesticide use. Over 80 pesticides and degradation products are determined in these samples. This document summarizes pesticide data for surf ace water and sediment samples collected from April 1992 to December 2007.3 Methods To assess ambient pesticide concentrati ons, surface water samples were generally collected on a quarterly basi s (four times annually) and sediment samples semi-annually (two times per year). The exact sampling date was dependent on staff and equipment availability as well as available capacity of the analytical laboratory. Samples were collected from a small boat or pier, upstream of each water control structure and away from canal banks. Water column samples were unfiltered surface grab samples (0.5 meter depth), while sediment samples were the top layer (approxima tely 10 centimeters) of sediment and obtained using a stainless steel petite Ponar dredge. Samples were stored on ice before being shipped to the analytical laboratory by overnight courier. All field and sampling procedures are described in cu rrent or previous ve rsions of the SFWMD Field Sampling Quality Manual (2008), whic h requires field quality control checks including field replicates, fiel d blanks, trip spikes (specifi c concentrations of selected analytes added to deionized or selected sa mple water), and equipment blanks (sediment only). These quality control samples were handled identically to field samples.

Samples have been analyzed for over 80 pestic ides and degradation products (Table 1). The list of compounds has been dynamic ove r time, with compounds added based on a potential concern or removed after evalua ting the compiled data and demonstrating no concern. The current analyti cal list is divided into chem ical groupings (chlorinated [phenoxy acid] herbicides, urea herbicid es, organochlorine pesticides, and organonitrogen/phosphorus pesticides) that ar e used by farmers and homeowners, which also includes restricted-use pesticides. Although listed, pol ychlorinated biphenyl’s are not pesticides, but are generally reported during organochlorine pesticide analysis. Selected compounds with a state-defined numer ic water quality standard (Chapter 62-302 F.A.C.) are provided in Table 2. The Unite d States Environmental Protection Agency (USEPA) National Recommended Water Quality Criteria ( 2006b) are also listed for comparison purposes. For any other com pound, an acute or chronic value can be calculated using procedures outlined in st ate law (62-302.200 (1)(a) and (4)(a) F.A.C.). Section 62-302.200 F.A.C. provides for acute and chronic toxicity standards to be
calculated as one-third and one-t wentieth, respectivel y, of the lowest concentration lethal to 50 percent of the test population (LC 50 ) exposed for 96 hours for a species significant to the indigenous aquatic community. The cal culated toxicity values are listed for the frequently detected compounds in Table 2. Se diment concentrations were compared to freshwater sediment quality assessment guidelines (MacDonald Environmental Sciences Ltd. and United States Geological Survey, 2003) (Table 3). A value below the threshold effect concentration (TEC) should not have a harmful effect on sediment-dwelling organisms. However, values above the proba ble effect concentration (PEC) demonstrate that harmful effects to sediment-dwelling organi sms are likely to be frequently or always
observed.

All analytical work associated with the pesticide monitoring network was performed by the Florida Department of Environmental Pr otection Central Laborat ory in Tallahassee, Florida. Analytical methods (Chemistry St andard Operating Procedures by Subsection: Organics) are available on the laboratory’s Web site ( www.dep.state.fl.us/labs/cgibin/sop/chemsop.asp ). The reported sediment concentra tions were on a dry weight basis.4 Since December 1994, modified analytical me thods have been used that lowered the
method detection limits about tenf old (Miles and Pfeuffer, 1997).

The tables summarizing the detected compounds were comp iled using the results the monitoring events from April 1992 to Decem ber 2007. Average, geometric mean, and
median concentrations were calculated usi ng only the detections for all locations. The
number of detections was based on the va lues above the minimum detection limit for each sampling event at all locations within th e land use or drainage basin type. With a few exceptions, as noted below, the summary data presented for the locations represent 68 surface water and 30 sediment sampling events.

Network Results and Discussion It is important to note that an evaluation of detection limits is critical when assessing pesticide data. For the surface water samples, the average number of compounds detected during a sampling event appeared to increase when the detection limits were decreased (Table 4). Scott et al. (2002) also noted increas es in pesticide surface water
detections in South Florida when the dete ction limits were decreased. Conversely, the
number of detected concentra tions in sediment samples decr eased when detection limits were lowered. This apparent discrepancy may be attributed to the fact that only four sampling events occurred duri ng the period of higher detec tion limits versus 26 for the lower detection limit time period (Table 4). Potentially, the most readily detected compounds (i.e., organochlorine compounds) in the sediment were prevalent during the earlier timeframe, since their use was only re cently restricted. Lower detection limits reduces false negatives.

For 44 percent of the monitoring locations, an average of three or more compounds was detected in the surface water during each sampling event (Table 5). The monitoring locations receiving drainage from citrus agriculture had the highest average (4) of different compounds detected, followed by th e northern EAA, southern EAA, urban, Lake Okeechobee inflows, South Miami-Dade County, and the reference drainage/land use type basins.

The percentage of detections by month, for the surface water samples ranged from 2.2 to 4.5 percent, with the pe riod of record averagi ng 3.3 percent (Figure 2) . A small seasonal difference in the number of detections was also observed between the wet and dry season averaging 3.1 and 3.4 percent, respectively. No pattern was evident due to the fact that the pesticide application peri od for the wide range of crops and their locations varies considerably throughout South Flor ida. For example, pesticide applicatio ns for citrus can occur year-round while row crop pesticide appl ications occur only in the appropriate timeframe during the specific growing season. Additionally, the seasonal temperature ranges for the growing season in the agricultural areas create a difference in the optimal start and end dates from the northern to the southern part of the region.

The percent detections by month, for the sedi ment ranged from 1.1 to 2.1 percent, with a period of record average of 1.6 percent (Figur e 3). The average number of detections for the wet and dry seasons was 1.3 and 1.6 percent, respectively. As was observed for the surface water, no pattern was ev ident since the application pe riod for the wide variety of5 crops and locations varied significantly. Additionally, the majority of detections consisted of p,p’-DDE and p,p’-DDE (Table 7).

The most frequently detected pesticides in surface water are the triazine herbicides (atrazine, ametryn, and simazine) (Table 6). These herbicides are applied to significant acreages in South Florida (Miles and Pfeuff er, 1997) and have a higher transport due to surface solution or leaching (Gross and Wauc hope, 1992). Atrazine and its associated degradation products, atrazine desethyl and atrazine de sisopropyl, were the most frequently detected compounds in the surface water. The most frequently detected pesticides in the sediment included the DDT metabolites (p,p’-DDE and p,p’-DDD) and ametryn (Table 7). Although banned in the early 1970s (USEPA, 1990), DDT and DDD were used widely, degrade slowly, and bind r eadily to soil. Atrazi ne, ametryn, atrazine desethyl, norflurazon, and p,p’-DDE were de tected in samples from at least one monitoring station during every event. The Un ited States Geological Survey, as part of
the South Florida National Ambient Wate r Quality Assessment (NAWQA), collected samples from 1996 to 1998 and identified similar compounds for the most frequently detected pesticides (McPherson et al., 2000).

Table 8 summarizes the atrazine surface wa ter detections by location. Structure S7 exhibited the highest detected maximum con centration of 18 micrograms per liter [μg/L] (Figure 4). Peak concentra tions routinely occurred duri ng April, coinciding with the application season for sugarcane. The draft ambient aquatic life water quality criterion identifies a one-hour average conc entration that does not exceed 1,500 μ g/L more than once every three years on the average (U SEPA, 2003a). Additionally, the lowest calculated chronic toxicity for the water flea, Daphnia magna , is 345 μg/L (Table 2). Based on these criteria, surface water concentrations presented in Table 8 should not have
an acute or chronic detrimental im pact on fish or invertebrates.

The highest atrazine average location concen tration in surface water was observed at S38B, which can receive runoff from an urban drainage basin (Table 8). The peak
atrazine detections o ccur in June, which coincides with the summer application season (Figure 5). The monitoring locations with th e next four highest average concentrations received drainage from the EAA. Nine of the top ten monitoring locations with the highest percentage of detections were either receiving runoff from the urban areas or the
EAA. The location with the hi ghest percent of detections wa s observed at S6 with peak concentrations occurring during April, whic h is the application season for sugarcane (Figure 6).

Results from the NAWQA program (McPherson et al., 2000) for atrazine surface water detections at S7 and S6 were very simila r to the SFWMD’s detections at the same locations. The peak concentrations measur ed during the NAWQA program also occurred during the spring months. However, NAWQA’ s highest detected concentration was 12 μg/L at S6.

Average annual atrazine concentrations fr om four northern and four southern boundary monitoring locations receiving drainage from the EAA are presented in Figures 7 and 8, respectively. Since 1992, a tr end towards lower detectable concentrations was observed6 for the southern and northern locations. A non-parametric regression (Theil) (Hollander, 1973) identified a significant (p value <0.05) decrease in concentra tion at all monitoring locations except S3 and S6. Theil regression makes no assumptions about the population
distribution and it does not assume the errors are only in the y-dire ction or are normally
distributed.

The average atrazine annual concentration from six monitoring locations receiving drainage from urban areas is presented in Fi gure 9. A statistically significant (p value <0.05) decrease in concentration based on the Theil regression (Hollander, 1973) was observed at all stations except S38B, G123, and S9.

The number of detections of p,p’-DDE in sedi ment is summarized by location in Table 9. Sediment samples were not collected at GORDYRD and CR33.5T due to access restrictions. The average con centration at S6, S2, S5A, and S178 for this parameter was higher than the PEC (i.e., 31 μg/Kg) suggesti ng that harmful effects to sediment-dwelling organisms are likely to be fr equently or always observed at these monitoring locations.

The locations with the highest percentage of detections and aver age concentration of p,p’-DDE were S5A, S2, S178, S177, S3, and S6 (Table 9 and Figure 10). Using a Theil non-parametric regression (Hollander, 1973), significant (p value <0.05) increases in concentration were observed at S2 and S3, wh ile a decreasing trend in concentration was
noted at S178 and S177. The thirteen locati ons exhibited p,p’-DDE detections 50 percent of the time or greater (Table 9) with the majority of sampling lo cations having average concentrations above the TEC (i.e., 3.2 μg/K g). Only eight locations (S331, L3BRS, S191, FECSR78, S9, US41-25, S65E, and S140) did not exceed the TEC.

Basin Results and Discussion Three locations (S65E, S191, and FECSR78) were sampled upstream of potential discharge into Lake Okeechobee (Figure 11). The agricultural activity in this basin is primarily cattle/dairy operati ons. Atrazine and its major degradation product (atrazine desethyl) were the dominant compounds detected in the surface water followed by the herbicides bromacil, hexazinone, and simazine (Table 10). However, the average
concentration for all these co mpounds were less than 1 ug/L and were appreciably below any level of concern for aqua tic invertebrates and fish (T able 2). Only p,p’-DDE was present with any frequency in the sediment s (Table 11). The maximum concentration exceeds the Florida freshwater sediment qua lity assessment guideline TEC but not the
PEC. A concentration above the TEC but le ss than the PEC has a potential for harmful effects on freshwater sediment dwelling organisms.

Six monitoring locations (S99, GORDYRD, S8 0, S78, CR33.5T, and S79) (Figure 12) were used to evaluate citrus agricultur e drainage. Sampling locations GORDYRD and
CR33.5T did not have sediment collected for an alysis due to access restrictions. A wide variety of herbicides and a few insecticides was detected at low concentrations in the surface water (Table 12). The herbicides norflurazon, simazine, atrazine, and bromacil were most frequently detected. Using a multiple substance risk approach, based on a concentration addition model, Schuler and Rand (2008) identified a high risk to plant and algal communities at S79, S80, and S99 from the herbicide mixtures detected at the7 respective locations.

The chemical of concern when evaluated on a single chemical to potential species toxicity is the organophosphate pesticide ethion, particularly at the S99 structure. Ethion is a non-systemic acaricide and insecticide previously registered for use on several fruits, citrus, and vegetables. Ethion is acutely toxic to aquatic orga nisms in low part per billion ranges (Mayer and Ellersieck, 1986, Table 2) an d is slightly toxic to mammals (Hartley and Kidd, 1987). Furthermore, it is stable to hydrolytic and photol ytic degradation in water (Montgomery, 1993). Ethion is strongly adsorbed to soil and therefore can accumulate in sediments (Gross and Wauchope , 1992). Ethion can bioconcentrate to a limited extent (Lyman et al., 1990).

However, ethion does not have a state numeric standard. The most sensitive species for aquatic macroinvertebrates in acute toxicity tests of ethion is the cladoceran, Daphnia

magna , with a 48-hour EC 50 of 0.06 μg/L (Table 2). The acute and chronic standards are 0.02 and 0.003 μg/L, respectively, calculated a ccording to the promulgated procedure (Section 62-302.200 F.A.C.). Based on these values, excursions of ethion concentration
above the established acute a nd chronic standards were observed (Figures 13a-d). Most
of the surface water detecti ons occurred during the growi ng season. Additionally, ethion detections were not routinely preceded by cons iderable rainfall. With a method detection limit of approximately 0.019 μ g/L, any detection will automatically exceed the calculated chronic toxicity. At this level, long-term exposure can cause impacts to macroinvertebrate populations, but the pulsed natu re of agricultural runoff releases to the canal system precludes drawing any conclusions about the e ffects of long-term average exposures. Since June 1992, 17 out of 41 samp ling events at S99 had a detectable level of ethion in the surface water (Figures 13a-d).

The use of ethion on citrus has been banne d (Federal Register, March 22, 2002). By December 31, 2004, all use of existing stocks of the end-use products was prohibited. With the voluntary cancellation of all regi stered products and the availability of alternative pesticides, the la st surface water detection occurred during the August 2001 sampling event (Figure 13d). A few sediment detections occurred after this time, with the last ethion residue qu antified during the October 2003 sampling event (Figure 13d).

In sediment samples from citrus drainage locations, p,p’-DDE was present along with ethion, PCB-1254, and p,p’-DDD (Table 13). Dieldrin and PCB-1254 were primarily detected at S79. The p,p’-DDE, dieldrin, a nd all of the PCB com pounds had average and
maximum concentrations that exceeded th e Florida freshwater sediment quality assessment guideline TEC (Table 13). No sediment guidelines are available for ethion.

Four locations, S2, S3, S4, and S235 (Figure 14), were used to evaluate drainage from the northern portion of the EAA, which is predominately sugarcane production, with some row crops such as corn and lettuce (vegetab le crops) or rice being grown. The most frequently detected pesticides were the herbicides atrazine, ametryn, hexazinone, and simazine (Table 14). For all of these, th e concentrations were below any levels of concern (Table 2). For the sediment samples, p,p’-DDE, p,p’-DDD, p,p’-DDT, chlordane, and the herbicide ametryn dominate d the number of detections (Table 15).8 Some of the p,p’-DDE, p,p’-DDD, chlordane, and toxaphene concentrations exceeded the PEC guideline. However, no sediment guidelines exist for ametryn.

Sampling locations S5A, S6, S7, S8, L3BRS , S190, S142, and S140 (Figure 15) were
used to evaluate surface runoff from the sout hern portion of the EAA. Structures S142 and S140 were added to the monitoring ne twork during the February 1997 sampling event and therefore the summary data repr esent only 44 events. The surface water pesticide detections in this region consiste d primarily of herbicides (Table 16). The concentrations were usually less than 1.0 μg/L , with atrazine, simazine, and diuron being the exceptions. With the exception of the maximum diuron concentration, none of the values exceeded any level of concern (Table 2). The 76 μg/L diuron detection exceeds the calculated chronic toxicity value for the invertebrate, Daphnia magna

.

Structures S7 and S8 were the only networ k sampling locations di rectly impacted by the operation of a Stormwater Treatment Area (S TA). Since STA-3/4 was completed in December 2004, flows from the North New River Canal are diverted into the over 16,000-acre treatment area before discharging ba ck to S7 and S8. Within STA-3/4, the vegetative communities were designed to pr ovide water quality treatment through an emergent macrophyte community as well as submerged aquatic vegetation. A comparison of atrazine and ametryn surface water concentrations before and after completion of STA-3/4 showed that the averag e concentration had decreased (Table 17). However, the percent of detections had in creased. STA-3/4 may have attenuated the herbicide concentration peaks and provided a more uniform distribution of the surface
water residues.

Herbicides and DDT metabolites were most fr equently detected in the sediment samples from the southern portion of the EAA (Table 18). Atrazine and ametryn residues in sediment corresponded with the consistent su rface water detections . The average p,p’- DDE, p,p’-DDD, p,p’-DDT, PCB-1242, PCB-1254, and PCB-1260 concentrations
exceeded the TEC while the chlordane concentration exceeded the PEC.

The majority of the sampling locations that r eceive drainage from urban areas have been recently added to the network (S9, G94D , ACME1DS, G123, S31, and S38B) (Figure 16). With the exception of water control st ructure S9 and S31, th e remaining locations have only been sampled since 1997/1998 and only represent 42 to 45 sampling events. After the March 2008 sampling event, the permit mandate for G94D, ACME1DS, and S38B was modified, deleting the requirement for sampling.

A wide variety of pesticides were detecte d, but the herbicides atrazine (and its major degradation products) and ametryn were most frequently detected in surface water, followed by hexazinone and simazine (Table 19). Like ethion, diazinon can have an acute or chronic toxicity standard calculate d based on one-third or one-twentieth of the
96-hour LC 50 for sensitive aquatic species. The most sensitive species is Daphnia magna (i.e., 48-hour EC 50 = 0.8 μg/L; Table 2) and the calcul ated acute and chronic standards are 0.3 and 0.04 μg/L, respectively. For th e S38B sampling location, four events (9/29/98-0.044; 1/6/99-0.067; 11/8/99-0.059; 8/8/00-0.06; method detection limit for all events: 0.019 μg/L) had detectab le concentrations above the chronic calculated standard.9 Whenever diazinon was present, it exceeded th e 0.04 μg/L calculated chronic criteria. However, the USEPA (USEPA, 2005) derived ambient freshwater qua lity criteria should not affect aquatic organisms if the one-hour average concentration does not exceed 0.17 μg/L more than once every three years on the average and if the four-day average concentration does not exceed 0.017 μg/L mo re than once every three years on the

average.

The most abundant of the measured sediment contaminants for urban basins were p,p’- DDE and p,p’-DDD (Table 20). The averag e concentrations of p,p’-DDE and PCB-1016
exceed the TEC for freshwater sediment.

The South Miami-Dade County agricultura l area supports a wide variety of predominately row crops (e.g., tomatoes, beans, and squash) and had five sampling locations (S332DX/S176, S177, S178, S18C, a nd S331) (Figure 17). Endosulfan has
been identified as the chemical of concern in this area, es pecially at S178 (Miles and Pfeuffer, 1997; Scott et al., 2002; Fulton et al., 2004), althou gh atrazine had the highest frequency of detection (Table 21). Th e maximum atrazine concentration was considerably lower than any levels of concern. Scott et al. (2002) repor ted atrazine detections over 92 percent of the time fr om 1996 to 1997 using a substantially lower detection level. Their peak c oncentration detected for atrazine was similar to the average concentration reported by SFWMD.

Endosulfan is used to control whiteflies on ve getable crops like tomatoes. It is a mixture of two insecticidal stereoisomers: alpha e ndosulfan and beta endosulfan. Endosulfan can be oxidized to endosulfan sulfate and hydroly zed to endosulfan diol. These metabolites
have been observed in surface waters near agricultural activity (National Research Council Canada, 1975). Endosul fan is highly toxic to aquatic organisms (Johnson and Finley, 1980; Mayer and Ellersieck, 1986). Furthermore, in a national summary of pesticides in coastal areas, endosulfan had the highest hazard rating of pesticides inventoried (Pait et al., 1992).

Endosulfan (alpha and beta) has a promulgated state standard of 0.056 μg/L (Table 2). A plot of the complete period of record of endosulfan detections at water control structure S178 showed eight endosulfan water quality excursions occurring out of the 67 sampling events primarily between early 1993 and 1996 (Figures18a-e). Endosulfan surface water detections were not routinely preceded by significant rainfall. Also the majority of the
endosulfan and endosulfan sulfate surface water detections corresponded with the growing season, which runs from September to April. Typically, sediment detections of
endosulfan occurred after the surface water detections. However, the frequency and magnitude of endosulfan detections have d ecreased since the 1994- 95 growing seasons. This may be attributed primarily to the availability of an alternative product (imidacloprid), grower education, and produc t label changes. The March 2007 detection (Figure 18e) was the last excursion since th e February 2000 sampling event (Figure 18c). McPherson et al. (2000) reporte d frequent endosulfan detect ions at S177 during 1996, but no excursions above the state standard. Detections became less frequent in the following two years of the monitoring program (McPherson et al., 2000).10 The DDT family of compounds was most often detected in the sediment in the South Miami-Dade County agricultural area along with numerous endosulfan detections (Table 22). The p,p’-DDE and p,p’-DDD average concen tration was greater than the TEC while the p,p’-DDE average maximum concentra tion was greater than the PEC. A
concentration above the TEC but less than th e PEC has a possibility of harmful effects on freshwater sediment dwelling organisms. A level above the PEC demonstrates that harmful effects to sediment-dwelling organism s are likely to be fr equently or always observed. No sediment guidelines are available for endosulfan. However, a two-tiered ecological risk assessment id entified endosulfan as having the highest po tential for chronic risk to aquatic arthropods at S178 (Carriger et al., 2006).

The last area of sampling by the SFWMD pesticide monitoring network covered the locations (US41-25 and S12A/S12C ) (Figure 19) that are consid ered relatively pristine,
since these locations are the furthest from any agricultural activity. The water source for these structures is primarily the remnant Everglades. These sampling locations are used as reference. However, even at these remote locations atrazine was still present (Table 23). The average maximum concentration how ever is only 0.52 μg/L, compared to 0.284 to 6.32 μg/L in agricultural areas. Sampling performed by Miller et al. (1999) at S12D over a two year period, detected atrazine con centrations very similar to those detected under the SFWMD monitoring program. Although not determined, atmospheric deposition may be the most probable source of atrazine detected at these locations (USEPA, 2006a). Also present in the sediment at these locations is the ubiquitous p,p’- DDE as well as PCB-1260 (Table 25). Even at these remote locations, the average maximum p,p’-DDE concentrati on was greater than the TEC.

Conclusions Due to the diverse variety of crops and the ex tensive spatial coverage of agriculture and urban areas as well as the large areal covera ge of the monitoring program, no discernable pattern of detections was evident unless th e data for a specific drainage basin are
examined. Pesticide detections occur more frequently during the application season for a crop or location. Due to this di versity, it is critical that the timing of sampling be varied. Although the monitoring was performed on a qu arterly basis, samp ling could occur any time within that quarter. For the surface water sampling events, each month was sampled between four and seven times (Figure 2). For the sediment samp ling, with the exception of September, between two and six sampling events were conducted per month (Figure 3). This randomness captured the vari ed periods of pes ticide application.

The level of detection is also critical for data evaluation. As identified for the insecticides ethion and diazinon, the concentratio ns at which a pesticide is of concern can be very low. Additionally lower detecti on limits also reduces the chance of false negatives.

For endosulfan and ethion, SFWM D data were used for the product label changes, which restricted or curtailed pestic ide application, helping to re duce environmental exposure. Additionally, SFWMD data were utilized in nine USEPA Reregistration Eligibility Decisions (RED) documents (USEPA, 1996a ; USEPA, 1996b; USEPA, 1998c; USEPA, 1998d; USEPA, 1999; USEPA, 2002b; USEP A, 2003b; USEPA, 2006c; and USEPA,11 2007). The RED documents summarize the ri sk assessment conclusions and outline any risk reduction measures necessary for a pestic ide to continue to be registered in the
United States.

Atrazine and its associated degradation products (atrazine dese thyl and atrazine desisopropyl) were the most frequently de tected compounds in the surface water while p,p’-DDE (the degradation product of DDT) was most frequently detected in the
sediment.

Atrazine was detected at all locations at leas t once. The top nine locations for detections or those with over 90 percent were locations receiving drainage from either the EAA or urban areas. However, none of the detected c oncentrations were at a level of concern as they did not exceed the draft ambient aquatic life water quality criterion or the calculated acute or chronic toxicity values. Nine of the 14 locations selected for evaluation demonstrated a decreasing concentra tion over time for this reporting period.

The p,p’-DDE residues were ubiquitous and the majority of sampling locations had
concentrations that could have harmful effects on freshwater sediment-dwelling organisms. Of the 32 locations evaluated, onl y eight had average location concentrations that were less than the TEC (i.e., the valu e at which sediment concentration should not have a harmful effect on sediment-dwelling or ganisms). The average concentration at S6, S2, S5A, and S178 was higher than the PEC, which means that harmful effects to sediment-dwelling organisms are likely to be frequently or always observed. Trend analysis for these structures, as well as S177 and S3, demonstrated increasing concentration at S2 andS3, while decreasing tr ends were demonstrated at S178 and S177. Although lawful uses of DDT in the United States were curtailed by the USEPA in the early 1970s (USEPA, 1990), the persistence of its predominant environmental metabolite p,p’-DDE, has resulted in residue concentrations that are still at a potentially harmful
level.

Since the sediment sampling upstream of the st ructures was performed at a fixed location,
it is difficult to determine what the sediment represents due to potential scouring during pumping or gate openings. Any sedime nt accumulation or removal upstream is dependent on the operation of the structure. To actually determine contemporary p,p’- DDE residues being transported by the opera tion of the canal system, a suspended particle trap could be deploye d to capture particulate materi al being transported in the canal. This would help identify which pest icides are being tran sported via suspended particulates in the respective canal. Sedime nt traps could be deployed over a specific time period to determine an integrated sediment pesticide contamination.

To determine exceedances of sediment or water quality criteria, pesticides concentrations from grab samples are typically compared to numerical standards or guidelines for sediment or water. However, specific criter ia are lacking for most of the pesticides.
Calculated criteria are based on the lowest acu te toxicity value from the most sensitive aquatic species tested in a short-term test. However, these values are often from species that are not native to south Florida ecosystems . In general, aquatic databases are limited for native species.12 Additionally, pesticide detecti ons frequently occur with more than one compound at a time. The most frequently detected pest icides in surface water were the triazine herbicides, while the DDT family was most often detected in the sediment. Although evaluated on a single compound to a single species criterion, a discernable impact is not always evident. However, if the same fam ily of compounds is detected, a synergistic or cumulative impact may be occurring. The current approach can be used to screen for chemicals of potential ecological concern. Probabilistic distributions of the detected concentrations could be compared to a proba bility distribution of effects data from relevant species. The resulting species se nsitivity distributions could be used to
characterize acute and chronic effects and th e susceptibility of organism to different
chemical stressors. This would determine wh at fraction of species is expected to be potentially affected above its acute or chr onic effect level at a given environmental
concentration.13 References Carriger, J.F., G.M. Rand, P.R. Gardinali, W.B. Perry, M.S. Tompkins, and A.M.
Fernandez. 2006. Pesticides of Potential Ecol ogical Concern in Sediment from South Florida Canals: An Ecological Risk Pr ioritization for A quatic Arthropods. Soil and
Sediment Contamination. 15:21-45.

Davis, R.A. (Ed.). 1970. Water Quality Criteria Data Book; Vol I-Organic Chemical Pollution of Freshwater . Prepared for the USEPA, Water Pollution Control Research Series 18010DPV12/70, Arthur D. Little, Inc. Cambridge, MA.

Federal Register: March 22, 2002 Vo lume 67, Number 56. pp. 13327 – 13328.

Fulton, M.H., G.I. Scott, M.E. DeLorenzo, P. B. Key, D.W. Bearden, E.D. Strozier, and C.J. Madden. 2004. Surface Water Pesticide Movement from the Dade County Agricultural Area to the Everglades and Florida Bay via the C-111 Canal. Bulletin of Environmental Contamination and Toxicology . 73:527-534.

Goss, D. and R. Wauchope. (Eds.). 1992. The SCS/ARS/CES Pesticide Properties Database: II Using It With Soils Data In A Screening Procedure . Soil Conservation Service. Fort Worth, TX.

Hartley, D. and H. Kidd. (Eds.). 1987. The Agrochemicals Handbook. Second Edition, The Royal Society of Chemistry. Nottingham, England.

Hollander, M. 1973. Nonparametric Statistical Methods. John Wiley and Sons, Inc. pp.
200 – 208.

Johnson, W.W. and M.T. Finley. 1980. Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates . U.S. Department of the Interior, Fish and Wildlife Service
Resource Publication 137. Washington, DC.

Lyman, W.J., W.F. Reehl, and D.H. Rosenblatt. 1990. Handbook of Chemical Property
Estimation Methods . American Chemical Society, Washington, DC.

MacDonald Environmental Sciences Ltd. a nd United States Geological Survey. 2003. Development and Evaluation of Numerical Se diment Quality Assessment Guidelines for Florida Inland Waters. Report to Florida Department of Envi ronmental Protection. Tallahassee, FL.

Mayer, F.L. and M.R. Ellersieck. 1986. Manual of Acute Toxicity: Interpretation and Database for 410 Chemicals and 66 Species of Freshwater Animals . United States Fish and Wildlife Service, Publication No. 160.

McPherson, B.F., R.L. Miller, K.H. Haa g, and A. Bradner. 2000. Water Quality in Southern Florida, 1996-98: U.S. Geological Survey Circular 1207, 32 p.14 Miles, C.J. and R. J. Pfeuffer. 1997. Pe sticides in canals of South Florida. Archives Environmental Contamination and Toxicology. 32, 337-45.

Miller, R.L., B.F. McPherson, and K.H. Haag. 1999. Water Quality in the Southern Everglades and Big Cypress Swamp in the Vicinity of the Tamiami Trail, 1996-97. U.S. Geological Survey Water-Resources Investigation Report 99-4062, 16 p.

Montgomery, J.H. 1993. Agrochemicals Desk Reference: Environmental Data . Lewis Publishers. Chelsea, MI.

National Research Council Canada. 1975. E ndosulfan: Its Effects on Environmental Quality. NRCC No. 14098. Ottawa, Canada.

Pait, A.S., A. E. De Souza, and D.R.G., Farrow. 1992. Agricultural pesticide in coastal areas: a national summary. Report for Strate gic Environmental A ssessment Division,
Office of Ocean Resources Conservation a nd Assessment, National Ocean Service, NOAA: Rockville, MD. 81 p.

Pfeuffer, R.J. 1985. Pesticide Residue Monitori ng in Sediment and Surface Water Within the South Florida Water Management Dist rict. Technical Publication 85-2, DRE 214, South Florida Water Management District, West Palm Beach, FL.

Pfeuffer, R.J. 1991. Pesticide Residue Monitori ng in Sediment and Surface Water Within the South Florida Water Management Distri ct: Volume 2. Technica l Publication 91-01, DRE 293, South Florida Water Management District, West Palm Beach, FL.

Schneider, B.A. (Ed.) 1979. Toxicology Handbook, Mammalian and Aquatic Data, Book 1: Toxicology Data . U.S. Environmental Protection Agency. U.S. Government Printing Office. Washington, DC . USEPA-5400/9-79-003.

Schuler L.J. and G.M. Rand. 2008. Aquatic Risk Assessment of Herbicides in Freshwater Ecosystems of South Florida, Archives Environmental Contamination and Toxicology. 54, No. 4.

Scott G.I., M.H. Fulton, E.F. Wirth, G.T. Chandler, P.B. Key, J.W. Daugomah, D. Bearden, K.W. Chung, E.D. Strozier, M. DeLore nzo, S. Sivertsen, A. Dias, M. Sanders, J.M. MaCauley, L.R. Goodman, M.W. LaCr oix, G.W. Thayer, and J. Kucklick. 2002. Toxicological Studies in Tropi cal Ecosystems: an Ecotoxico logical Risk Assessment of
Pesticide Runoff in South Fl orida Estuarine Ecosystems. Journal Agricultural and Food Chemistry 50, 4400-4408.

South Florida Water Management Distri ct. 2008. Field Sampling Quality Manual, SFWMD-FIELD-QM-001-04, effective date May 30, 2008.

United States Environmental Protection Agenc y. 1972. Effects of Pesticides in Water: A Report to the States. U.S. Governme nt Printing Office. Washington, DC.15 _____ 1977. Silvacultural Chemicals and Protection of Water Quality . Seattle, WA.
EPA-910/9-77-036.

_____ 1990. Suspended, Cancelled, and Restricted Pesticides. Pesticides and Toxic Substances, 20T-1002, February 1990.

_____ 1991. Pesticide Ecological Effects Database . Ecological Effects Branch, Office of Pesticide Programs, Washington, DC.

_____ 1994a. Reregistration Eligibility Deci sion (RED) Hexazinone, EPA 738-R-94-022. September 1994.

_____ 1994b. Reregistration Eligibility Deci sion (RED) Metalaxyl, EPA 738-R-94-017. September 1994.

_____1996a. Registration Eligibility Deci sion Norflurazon List A Case 0229.

_____ 1996b. Registration Eligibility Decisi on (RED) Bromacil. EPA 738-R-96-013. August 1996.

_____ 1996c. Registration Eligibility Decision (RED) Prometryn. EPA 738-R-95-033. February 1996.

_____ 1998a. Transmittal of EFAD (Environmenta l Fate and Effects Division) List A Summary Report for Ethion (Che mical #58401) Case #0090. August 7, 1998.

_____ 1998b. Reregistration Eligibility Decisi on (RED) Metribuzin. EPA 738-R-97-006. February 1998.

_____ 1998c. Reregistration Eligibility Deci sion (RED) Dicofol. EPA 738-R-98-018.
November 1998.

_____ 1998d. Reregistration Eligibility Deci sion (RED) Methomyl . EPA 738-R-98-021.
December 1998.

_____ 1998e. Reregistration Eligibility Deci sion (RED) Alachlor. EPA 738-R-98-020.
December 1998.

_____ 1999. Reregistration Eligibility Deci sion (RED) Chlorothalonil EPA 738-R-99- 004. April 1999.

_____ 2002a. Reregistration Eligibility D ecision for Endosulfan. EPA 738-R-02-013.
November 2002.

_____ 2002b. Interim Reregistration Eligibili ty Decision (IRED) Fenamiphos. EPA 738- R-02-004. May 2002.16 _____ 2002c. Interim Reregistration Eligibility Decision for Chlorpyrifos; EPA 738-R01-007. February 2002.

_____ 2002d. Interim Reregistration Eligibility Decision for Nale d; EPA 738-R-02-008. January 2002.

_____ 2003a. Ambient Aquatic Life Water Crit eria for Atrazine. Revised Draft EPA822-R-03-023. October 2003.

_____ 2003b. Reregistration Eligibility Deci sion (RED) for Diuron. September 30, 2003.

_____ 2004. Interim Reregistration Eligibil ity Decision Diazinon. EPA 738-R-04-006. May 2004.

_____ 2005. Aquatic Life Ambient Water Qual ity Criteria, Diazi non Final. EPA-822-R05-0906. December 2005.

_____ 2006a. Decisions Document for Atrazine.

_____ 2006b. National Recommended Water Qual ity Criteria. Office of Water and Office of Science and Technology.

_____ 2006c. Addendum to the 2001 Ethoprop In terim Reregistration Eligibility Decision (IRED) EPA 738- R-06-018. February 2006.

_____ 2007. Appendix 1 to 2007 Addendum: Envir onmental Fate and Ecological Risk Assessment of Endosulfan EPA-HQ-OPP-2002-0262-0063.1. October 2007.

Verschueren, K. 1983. Handbook of Environmental Data on Organic Chemicals . Second Edition, Van Nostrand Reinhold Co. Inc. New York, NY.17 Figure 1. South Florida Water Management District Pesticide Monitoring Network.18 Table 1. Pesticides determined in samples taken by the South Florida Water Management District ambient pesticide monitoring network.

Pesticide Surface Water Sediment Pesticide Surface Water Sediment Chlorinated (phenoxy acid) Herbicides Organochlorine Pesticides 2,4-D X X aldrin X X 2,4,5-T X X alpha hexachlorocyclohexane (BHC) X X 2,4,5-TP (silvex) X X beta hexachlorocyclohexane (BHC) X X
acifluorfen X (1) X (2) delta hexachlorocyclohexane (BHC) X X Urea Herbicides and Imidacloprid gamma BHC (lindane) X X
diuron X X carbophenothion X X
linuron X X chlordane X X imidacloprid X (3) - chlorothalonil X X Organonitrogen and Phosphorus Pesticides cypermethrin X X (6)

alachlor X X p,p’-DDD X X
ametryn X X p,p’-DDE X X
atrazine X X p,p’-DDT X X atrazine desethyl X (4) - dicofol (kelthane) X X atrazine desisopropyl X (4)

- dieldrin X X azinphos methyl (guthion) X X alpha endosulfan X X
bromacil X X beta endosulfan X X butylate X
- endosulfan sulfate X X chlorpyrifos ethyl X X endrin X X chlorpyrifos methyl X X endrin aldehyde X X
demeton X X heptachlor X X
diazinon X X heptachlor epoxide X X
disulfoton X X methoxychlor X X
ethion X X mirex X X ethoprop X X permethrin X X (6) fenamiphos X X PCB-1016 X X fonophos X X PCB-1221 X X
hexazinone X (7) X (7) PCB-1232 X X

malathion X X PCB-1242 X X metalaxyl X - PCB-1248 X X methamidophos X (5) X PCB-1254 X X
metolachlor X X PCB-1260 X X
metribuzin X X toxaphene X X mevinphos X X trifluralin X X monocrotophos X (5) X Dipyridillium Herbicides

naled X (8) X (8) paraquat X (5) X (5)

norflurazon X (7) X (7) diquat X (5) X (5)
parathion ethyl X X Water Soluble Pesticides parathion methyl X X acephate X (5)

- phorate X X dimethoate X (5)

- prometon X (6) - monocrotophos X (5) X prometryn X X Phosphonoglycine Herbicide
simazine X X glyphosate X (5)

- Carbamates Benzimidazole Fungicide

aldicarb X (5) X (5) benomyl X (5) X (5) carbaryl X (5) X (5) Ethylenebisdithiocarbamate Degradation Product

carbofuran X (5) X (5) ethylene thiourea X (5)

- methomyl X (5) X (5) oxamyl X (5) X (5)

Compounds in italics have a Florida Administrative Co de 62-302 Water Quality Class I or III criterion. - : pesticide not analyzed in matrix (1) added November 2002 sampling event (2) added May 2001 sampling event (3) added February 1997 sampling event (4) added November 1999 sampling event (5) not analyzed after May 1997 sampling event (6) added December 2001 sampling event (7) added December 1994 sampling event (8) added March 2001 sampling event19Table 2. Freshwater surface water quality criteria and toxicity of selected pesticidesto freshwater aquatic invertebrates andfishes (μg/L).* CMC (criteria maximum concentration) is the highest concentration ofa pollutant in surface water towhich aquatic life can be exposed for a short period of time (1-hour average) without deleterious effects (40CFR131.36, July 1, 2005)** CCC (criteria continuous concentration) is the highest concentration of a pollutant in surface water to which aquatic life can be exposed for an extended period of time (4 days) without deleterious effects (40CFR131.36, July 1, 2005)*** Florida Administrative Code Section 62-302.200, for compoundsnot specifically listed, acute and chronic toxicity standardsare calculated as one-third and one-twentieth, respectively, of the amount lethal to 50% of the test organisms in 96hours, where the 96 hour LC50is the lowest value which has been determined for a species significant to the indigenous aquatic community.(1) Johnson and Finley, 1980; (2) Schneider, 1979; (3) USEPA, 1972; (4) Hartley and Kidd, 1987; (5) Montgomery, 1993; (6) Verschueren, 1983; (7) USEPA, 1991; (8) Mayer and Ellersieck, 1986; (9) USEPA, 2006a; (10) USEPA, 2004; (11)USEPA, 2003b; (12) USEPA, 2002a; (13) USEPA, 1994a; (14) USEPA, 1994b; (15) USEPA, 1998a; (16) USEPA, 1998b; (17) USEPA, 1996a;(18) USEPA, 1996b; (19) USEPA, 2006b; (20) USEPA, 2002c; (21) USEPA, 1977; (22) Davis,1970; (23) USEPA, 1996c; (24) USEPA, 1998e; (25) USEPA, 2002dPesticideFlorida AdministrativeCode 62-302USEPA(19)WaterFleaDaphnia magnaBluegillLepomis macrochirusLargemouth BassMicropterus salmoidesChannel CatfishIctalurus punctatusClass I Class III CMC*CCC**48 hr EC50AcuteToxicity***ChronicToxicity***96 hr LC50AcuteToxicityChronicToxicity96 hr LC50AcuteToxicityChronicToxicity96 hr LC50AcuteToxicityChronicToxicity2,4-D≤100 - - - 25,000(9) 8,333 1,250 180,000 (8) 60,000 9,000 - - - - - -- - - 900 (48 hr) (6) 113 25 - - - - - -alachlor - - - - 21,000 (7) 7,000 1,050 2,800 (4) 933 140 - - - - - -10,000 (24) 3,333 500 4,300 (24) 1,433 215 - - - - - -ametryn - - - - 28,000 (7) 9,333 1,400 4,100 (4) 1,367 205 - - - - - -atrazine - - - - 6,900 (7) 2,300 345 16,000 (4) 5,333 800 - - - 7,600 (4) 2,533 380bromacil - - - - - - - 127,000 (7) 42,333 6,350 - - - - - -121,000 (18) 40,333 6,050 127,000 (18) 42,333 6,350 - - - - - -chlorpyrifos(ethyl)- - 0.083 0.041 1.7 (7) 0.57 0.085 2.6 (4) 0.87 0.13 - - - 280 (7) 93 140.1 (7) 0.03 0.005 5.8 (7) 1.9 0.3 - - -0.1 (20) 0.03 0.005 1.8 (20) 0.6 0.1 - - -diazinon - - 0.17 0.17 0.8 (1) 0.3 0.04 168 (1) 56 8.4 - - - - - -0.9 (3) 0.3 0.045 165 (2) 55 8.3 - - - - - -- - - 16,000 (4) 5,333 800 - - - - - -0.83 (10) 0.28 0.04 460 (10) 153 23 - - - - - -diuron - - - - 1,400 (7) 457 70 5,900 (4) 1,967 295 - - - - - -1,400 (11) 457 70 - - - - - - - - -endosulfan≤0.056≤0.056 0.22 0.056 166 (7) 55 8 1 (1) 0.3 0.05 - - - 1 (1) 0.3 0.05- - - 2 (2) 0.67 0.10 - - - 1.5 (7) 0.5 0.08166 (12) 55 8 1.7 (12) 0.57 0.09 - - - - - -ethion - - - - 0.06 (1) 0.02 0.003 210 (1) 70 11 173 (1) 58 9 7,600 (1) 2,533 380- - - 13 (2) 4.3 0.65 150 (3) 50 8 7,500 (3) 2,500 375- - - 22 (3) 7.3 1.1 - - - - - -0.056 (15) 0.02 0.003 210 (15) 70 11 173 (15) 58 9 - - -ethoprop - - - - 93 (7) 31 4.7 - - - - - - - - -hexazinone - - - - 151,600 (7) 50,533 7,580 100,000 (7) 33,333 5,000 - - - - - -151,600 (13) 50,533 7,580 505,000 (13) 168,333 25,250 - - - - - -malathion≤0.1≤0.1 - 0.1 1 (1) 0.3 0.05 103 (1) 34 5.2 285 (1) 95 14 8,970 (1) 2,990 4491.8 (3) 0.6 0.09 100 (21) 37 5.5 - - - 7,620 (7) 2,540 38112 (22) 4 0.6 - - - - - -metalaxyl - - - - 28,000 (7) 9,333 1,400 139,000 (7) 46,333 6,950 - - - - - -29,000 (14) 9,667 1,450 139,000 (7) 46,333 6,950 - - - - - -metolachlor - - - - 23,500 (7) 7,833 1,175 15,000 (4) 5,000 750 - - - 4,900 (5) 1,633 245metribuzin - - - - 4,200 (7) 1,400 210 80,000 (4) 26,667 4,000 - - - 100,000 (7) 33,333 5,0004,200 (16) 1,400 210 75,900 (16) 25,300 3,795 - - - - - -naled - - - - 0.3 (25) 0.1 0.02 2,200 (25) 733 110 1,900 (25) 633 95 710 (25) 237 36norflurazon - - - - 15,000 (7) 5,000 750 16,300 (7) 5,433 815 - - - >200,000 (4) >67,000 >10,000>15,000 (17) >5,000 >750 16,300 (17) 5,433 815 - - - - - -prometryn - - - - 18,590 (23) 6,197 930 10,000 (23) 3,333 500 - - - - - -prometon - - - - - - - 40,000 (5) 13,333 2,000 - - - - - -simazine - - - - 1,100 (7) 367 55 90,000 (4) 30,000 4,500 - - - - - -20 Table 3. Freshwater sediment assessment guidelines (1)

.

Parameter Threshold Effect
Concentration (2) (μg/Kg) Probable Effect
Concentration (3) (μg/Kg)
atrazine 0.30 NG azinphos ethyl 0.018 NG azinphos methyl 0.062 NG
total chlordane 3.2 18
diazinon 0.38 NG
dieldrin 1.9 62

sum DDD 4.9 28

sum DDE 3.2 31

sum DDT 4.2 63
total DDT 5.3 570
endrin 2.2 210 heptachlor epoxide 2.5 16
lindane 2.4 5.0
malathion 0.67 NG
simazine 0.34 NG toxaphene 0.10 32
total PCB’s 60 680

NG: no guideline
(1) MacDonald Environmental Sciences, Ltd. an d United States Geolog ical Survey (2003)
(2) Threshold Effect Concentration: The threshold effect concentration is intended to identify concentrations below which harmful effects on freshwater sediment–dwelling organisms are unlikely to be observed.
(3) Probable Effect Concentration: The probable effect concentration is intended to identify concentrations above which harmful effects on freshwater sediment-dwelling organisms are likely to be frequently or always observed.

Table 4. Number of pesticide detections per sampling event.

Higher Detection Levels April 1992 to September 1994 Lower Detection Levels
December 1994 to December 2007
Surface Water Sediment Surface Water Sediment
Number of Sampling

Events 15 4 53 26

Average
Number of
Detections 22 32 84 30

Percent
Detections 1.2 2.2 3.7 1.521 Table 5. Number of pesticides detected dur ing a surface water sampling event by location from April 1992 to December 2007.

Land Use or Drainage Basin Type Location Average Number of
Pesticides Detected per Sampling Event Median Number of
Pesticides Detected per Sampling Event
Lake Okeechobee
inflow S65E 1 1

S191 1 1
FECSR78 1 1
citrus S99 3 3

GORDYRD 3 3
S80 3 3
CR33.5T 5 5

S78 4 4
S79 5 5
northern EAA S2 3 3

S3 3 3
S4 3 3
S235 3 3
southern EAA S5A 3 3

S6 3 3
S7 2 2
S8 2 2

L3BRS 2 2
S190 2 2
S142 2 2

S140 2 2
urban S9 1 1

G94D 3 3

ACME1DS 3 3
G123 1 1
S31 1 1

S38B 3 4
South Miami-Dade County S332DX/S176 1 1

S177 1 1
S178 2 2

S18C 1 1
S331 1 1
reference US421-25 0 0
S12A/S12C 1 1 EAA: Everglades Agricultural Area22 Figure 2. Average percentage of pesticide surface water detections by month sampled (April 1992 to December 2007).

Figure 3. Average percentage of pesticide se diment detections by month sampled (April 1992 to December 2007). 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

0 1 2 3 4 5 6 7 8

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecPercent DetectionNumber Sampling Events

Month number sampling events average percent detection monthly average

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0

0 1 2 3 4 5 6 7

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecPercent DetectionNumber Sampling Events

Month number sampling events average percent detection monthly average23 Table 6. Twenty most frequently detected pesticides and degradation products in surface water (April 1992 to December 2007).

Action Pesticide or Degradation Product Number Detections Number Sampling
Events With No
Detections
herbicide atrazine 1,517 0 herbicide ametryn 714 0
herbicide simazine 472 1
atrazine desethyl 448 0
herbicide norflurazon 397 0
herbicide hexazinone 364 3
herbicide bromacil 342 3
atrazine desisopropyl 173 6
herbicide diuron 97 28 insecticide alpha endosulfan 82 38
endosulfan sulfate 81 19
herbicide metolachlor 58 36
insecticide beta endosulfan 42 44 herbicide 2,4-D 30 47
insecticide ethion 27 45 insecticide ethoprop 22 56
herbicide metribuzin 18 53 insecticide metalaxyl 15 54
insecticide diazinon 15 56 herbicide prometon 11 1924 Table 7. Twenty most frequently detected pesticides and degradation products in sediment (April 1992 to December 2007).

Action Pesticide or Degradation Product Number Detections Number Sampling
Events With No
Detections p,p’-DDE 367 0 insecticide p,p’-DDD 150 1 herbicide ametryn 92 3
PCB-1254 41 9 insecticide p,p’-DDT 32 7
insecticide beta endosulfan 26 12
endosulfan sulfate 26 11
insecticide ethion 24 13
insecticide chlordane 23 15
herbicide atrazine 22 17 insecticide alpha endosulfan 18 16
insecticide dieldrin 15 19
PCB-1260 11 20
insecticide dicofol 10 27 herbicide diquat 9 8
herbicide bromacil 8 25
herbicide norflurazon 7 20

PCB-1242 5 27
herbicide diuron 5 27
PCB-1016 3 28
insecticide aldrin 3 2725 Table 8. Atrazine surface wa ter detection summary by sampling location from April 1992
to December 2007.

Location Drainage Basin Type Percent
Detections Number
of Times Sampled Average
Concentration (μg/L) Maximum
Concentration (μg/L)
S6 southern EAA 97 67 0.88 6.8
S38B urban 95 40 1.42 4.4
ACME1DS urban 95 42 0.21 1.3
G94D urban 95 43 0.20 1.5
S3 northern EAA 94 68 0.26 0.78
S5A southern EAA 93 67 1.07 11
S4 northern EAA 91 68 0.56 7.1
S2 northern EAA 91 68 0.41 4.9
S7 southern EAA 90 67 0.86 18
S78 citrus 90 68 0.36 2.2
S235 northern EAA 88 68 0.48 8.5
S8 southern EAA 87 67 1.01 12
CR33.5T citrus 87 68 0.67 12
S79 citrus 85 68 0.36 2.3
S142 southern EAA 83 43 0.13 0.58
G123 urban 71 40 0.14 1.9
S80 citrus 68 68 0.17 1
L3BRS southern EAA 66 67 0.24 1.7 S331 South Miami-Dade County 64 43 0.04 0.22
S65E Lake Okeechobee inflow 60 68 0.07 0.2
S31 urban 57 67 0.2 1.5
S9 urban 54 67 0.101 0.32
S12A/S12C reference 53 67 0.08 0.93
S140 southern EAA 53 43 0.062 0.17 S332DX/S178 South Miami-Dade County 50 67 0.062 0.4 S18C South Miami-Dade County 50 67 0.049 0.31 S177 South Miami-Dade County 47 67 0.058 0.4
S191 Lake Okeechobee inflow 46 68 0.08 0.4
S190 southern EAA 46 67 0.063 0.32 S178 South Miami-Dade County 46 67 0.035 0.089
FECSR78 Lake Okeechobee inflow 40 68 0.07 0.26
US41-25 reference 21 67 0.023 0.10
S99 citrus 9 68 0.018 0.032
GORDYRD citrus 3 33 0.03 0.03 EAA: Everglades Agricultural Area26 Figure 4. Atrazine surface water co ncentrations detected at S7.

Figure 5. Atrazine surface water co ncentrations detected at S38B. 0 2 4 6 8 10 12 14 16 18 20Concentration (μg/L)

Date

0 0.5

1 1.5

2 2.5

3 3.5Concentration (μg/L)

Date27 Figure 6. Atrazine surface water co ncentrations detected at S6.

Figure 7. Annual atrazine surface water concentr ations at locations receiving drainage from the northern Everglades Agricultural Area. 0 1 2 3 4 5 6 7Concentration (μg/L)

Date

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00Average Annual Concentration (μg/L)

Year S2 S3 S4 S23528 Figure 8. Annual atrazine surface water concentr ations at selected locations receiving drainage from the southern Ev erglades Agricultural Area.

Figure 9. Annual atrazine surface water concentr ations at locations receiving drainage
from urban areas. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00Average Annual Concentration (μg/L)

Year S5A S6 S7 S8

0 0.25

0.5 0.75 1 1.25

1.5 1.75 2 2.25Average Annual Concentration (μg/L)

Year S38B ACME1DS G94D G123 S31 S929 Table 9. Summary of p,p’-DDE sediment de tections by sampling location from April
1992 to December 2007.

Location Percent
Detections Number of
Times Sampled Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg)

S5A 93 30 53 300

S2 90 30 78 393

S178 90 30 40 89

S177 87 30 21.6 70

S3 83 30 26 92

S6 77 30 98 390

S4 73 30 19.3 58

S31 70 30 9.8 21
S79 63 30 9.9 18
S80 63 30 6.2 11
S8 53 30 4.5 13
S7 50 30 11 55
G94D 50 22 4.4 10
S332DX/S176 33 30 5 18
ACME1DS 48 21 4.3 7.9
S142 41 22 8 21
S99 23 30 4.5 11
S18C 23 30 3.5 8.7
S331 32 22 2.6 3.9
S190 20 30 4.6 15
L3BRS 13 30 2.7 3.4
G123 15 20 6.9 11
S78 10 30 3.2 4.5
S191 10 30 2.9 4.7
S235 7 30 10 18
S12A/S12C 7 30 4.3 6.3

S38B 5 19 4.6 4.6

FECSR78 3 30 2.8 2.8
S9 3 29 2.2 2.2
US41-25 3 30 1.4 1.4

S65E 0 30 0 0
S140 0 22 0 0

Italicized values exceed the Threshold Effect Concentration (TEC): 3.2 μg/Kg
Bold values exceed the Probable E ffect Concentration (PEC): 31 μg/Kg) (MacDonald Environmental Sciences, Ltd. a nd United States Geological Survey, 2003)30Figure 10. Biannual p,p’-DDE sediment concentrations from selected locations from April 1992 to December 2007.050100150200250300350400

Concentration (μg/Kg)DateS5AS2S178S177S3S6Threshold Effect ConcentrationProbable Effect Concentration31 Figure 11. Lake Okeechobee basin sampling locations.32 Table 10. Surface water pesticide detections for Lake Okeechobee basin sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/L) Maximum
Concentration (μg/L) Concentration
Geometric

Mean Median
Concentration

atrazine 99 0.08 0.40 0.05 0.06
bromacil 57 0.11 1.2 0.08 0.08
hexazinone 37 0.13 1.3 0.07 0.06
atrazine desethyl 25 0.02 0.042 0.023 0.023

simazine 24 0.06 0.50 0.04 0.03
norflurazon 15 0.07 0.16 0.05 0.05 2,4-D 5 0.96 3.3 0.80 0.79
metolachlor 5 0.10 0.24 0.09 0.08 ametryn 2 0.034 0.049 0.034 0.034
metribuzin 2 0.052 0.071 0.048 0.052

Table 11. Sediment pesticide detections fo r Lake Okeechobee basin sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg) Threshold
Effect
Concentration (μg/Kg) Probable
Effect
Concentration (μg/Kg) p,p’-DDE 4 2.8 4.7 3.2 31 diquat 2 940 1100 - - Italicized values exceed the Threshold Effect Concentration (TEC) - No guideline available33 Figure 12. Citrus agriculture sampling locations.34 Table 12. Surface water pesticide detections for citrus agriculture sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/L) Maximum
Concentration (μg/L) Concentration
Geometric

Mean Median
Concentration

norflurazon 264 0.48 3.9 0.34 0.35
simazine 258 0.22 7.3 0.08 0.07
atrazine 231 0.27 12 0.13 0.13
bromacil 208 0.64 8.6 0.31 0.32
atrazine desethyl 101 0.03 1.0 0.024 0.022

hexazinone 94 0.041 0.75 0.029 0.024 ametryn 85 0.03 0.21 0.022 0.018
diuron 67 0.99 16 0.51 0.49
atrazine desisopropyl 60 0.02 0.13 0.02 0.02

ethion 25 0.11 0.83 0.065 0.055
metolachlor 12 0.16 1.2 0.11 0.11 metalaxyl 9 0.09 0.21 0.11 0.10 2,4-D 6 1.96 4.1 1.7 1.7
endosulfan
sulfate 4 0.027 0.048 0.026 0.027

malathion 4 0.06 0.14 0.053 0.048 alpha
endosulfan 3 0.0036 0.0065 0.0031 0.0022

metribuzin 3 0.04 0.056 0.041 0.041
beta
endosulfan 2 0.0043 0.0052 0.0043 0.0043

ethoprop 2 0.036 0.039 0.036 0.03635Figure 13a. Ethion detections in surface water at S99 from March 1992 to March 1995.

7-Day Antecendent Rainfall, Inches0123456growing seasonsampling event7-day antecendent rainfall

Ethion in Surface Water, μg/L0.00.10.20.30.4growing seasonsampling eventethionethion 48 hr EC50Daphnia magnaethion calculated acute toxicityethion calculated chronic toxicity

M a r - 9 2 J u n - 9 2 S e p - 9 2 D e c - 9 2 M

a r - 9 3 J u n - 9 3 S e p - 9 3 D e c - 9 3 M

a r - 9 4 J u n - 9 4 S e p - 9 4 D e c - 9 4 M

a r - 9 5

Ethion in Sediment, μg/Kg01020304050growing seasonsampling eventethion36Figure 13b. Ethion detections in surface water at S99 from March 1995 to March 1998.

7-Day Antecendent Rainfall, Inches0123456growing seasonsampling event7-day antecendent rainfall

Ethion in Surface Water, μg/L0.00.10.20.30.4growing seasonsampling eventethionethion 48 hr EC50Daphnia magnaethion calculated acute toxicityethion calculated chronic toxicity

M a r - 9 5 J u n - 9 5 S

e p - 9 5 D e c - 9 5 M

a r- 9 6 J u n - 9 6 S

e p - 9 6 D e c - 9 6 M

a r - 9 7 J u n - 9 7 S

e p - 9 7 D e c - 9 7 M

a r- 9 8

Ethion in Sediment, μg/Kg01020304050growing seasonsampling eventethion37Figure 13c. Ethion detections in surfacewater at S99 from March 1998 to May 2001.

7-Day Antecendent Rainfall, Inches0123456growing seasonsampling event7-day antecendent rainfall

Ethion in Surface Water, μg/L0.00.10.20.30.4growing seasonsampling eventethionethion 48 hr EC50Daphnia magnaethion calculated acute toxicityethion calculated chronic toxicity

M a r - 9 8 J

u n

- 9 8 S

e p - 9 8 D

e c - 9 8 M

a r - 9 9 J

u n

- 9 9 S

e p - 9 9 D

e c - 9 9 M

a r - 0 0 J

u n

- 0 0 S

e p - 0 0 D

e c - 0 0 M

a r - 0 1

Ethion in Sediment, μg/Kg01020304050growing seasonsampling eventethion38Figure 13d. Ethion detections in surface water at S99 from June 2001 to May 2004..

7-Day Antecendent Rainfall, Inches0123456growing seasonsampling event7-day antecendent rainfall

Ethion in Surface Water, μg/L0.00.10.20.30.4growing seasonsampling eventethionethion 48 hr EC50Daphnia magnaethion calculated acute toxicityethion calculated chronic toxicity

J u n - 0 1 Se

p - 0 1 D

e c - 0 1 Ma

r- 0 2 J u n - 0 2 Se

p - 0 2 D

e c - 0 2 M

a r- 0 3 J u n - 0 3 Se

p - 0 3 D

e c - 0 3 M

a r- 0 4

Ethion in Sediment, μg/Kg01020304050growing seasonsampling eventethion39 Table 13. Sediment pesticide detections for citrus agriculture sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg) Threshold
Effect
Concentration (μg/Kg) Probable
Effect
Concentration (μg/Kg) p,p’-DDE 41 6.4 18 3.2 31
ethion 20 9.8 46 - -

PCB-1254 20 133 290 60 680 p,p’-DDD 11 4 11 4.9 28
norflurazon 7 17.9 15 - -
dicofol 5 12.9 26 - -
dieldrin 5 7.0 11 1.9 62
diuron 2 19.5 21 - -

PCB-1242 2 79.5 89 60 680 Italicized values exceed the Threshold Effect Concentration (TEC) - No guideline available40 Figure 14. Everglades Agricultural Area northern sampling locations.41 Table 14. Surface water pesticide detections for Everglades Agricultural Area northern sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/L) Maximum
Concentration (μg/L) Concentration
Geometric

Mean Median
Concentration

atrazine 248 0.43 8.5 0.24 0.23 ametryn 174 0.11 1.0 0.05 0.05
atrazine desethyl 110 0.03 0.1 0.028 0.029

hexazinone 80 0.03 0.41 0.03 0.03
simazine 65 0.06 0.79 0.03 0.02
atrazine desisopropyl 36 0.02 0.079 0.015 0.014

norflurazon 15 0.11 1.3 0.07 0.07
bromacil 12 0.13 1.1 0.09 0.08 ethoprop 12 0.07 0.22 0.05 0.06
metolachlor 7 0.30 1.4 0.17 0.14
diazinon 3 1.05 1.9 1.0 1.0
diuron 3 0.61 0.8 0.6 0.6 2,4-D 2 3.1 4.9 3.1 3.1 chlorpyrifos ethyl 2 0.051 0.085 0.051 0.051

metribuzin 2 0.021 0.022 0.021 0.02142 Table 15. Sediment pesticide detections fo r Everglades Agricultural Area northern sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg) Threshold
Effect
Concentration (μg/Kg) Probable
Effect
Concentration (μg/Kg) p,p’-DDE 76 33 393 3.2 31 p,p’-DDD 57 12 80 4.9 28 ametryn 39 20 56 - - p,p’-DDT 12 14 78 4.2 63
chlordane 10 64 260 3.2 18
atrazine 6 8 17 - -
dieldrin 4 7 20 1.9 62
aldrin 2 7 11 - -

PCB-1254 2 66 82 60 680 Italicized values exceed the Threshold Effect Concentration (TEC)
Bold values exceed the Probable Effect Concentration (PEC) - No guideline available43 Figure 15. Everglades Agricultural Area southern sampling locations.44 Table 16. Surface water pesticide detections for Everglades Agricultural Area southern sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/L) Maximum
Concentration (μg/L) Concentration
Geometric

Mean Median
Concentration

atrazine 378 0.53 18 0.19 0.17 ametryn 257 0.052 0.67 0.03 0.03
norflurazon 95 0.061 0.21 0.05 0.05
atrazine desethyl 79 0.05 0.37 0.02 0.02

hexazinone 90 0.06 1.7 0.03 0.03
simazine 82 0.105 9.3 0.03 0.02
bromacil 49 0.163 1.4 0.10 0.11
metolachlor 32 0.158 0.44 0.14 0.15
atrazine desisopropyl 20 0.019 0.031 0.017 0.018

metribuzin 7 0.19 0.51 0.19 0.17
diuron 6 9.69 76 1.5 3.3 ethoprop 6 0.136 0.67 0.09 0.09 prometryn 6 0.139 0.59 0.06 0.03
endosulfan
sulfate 5 0.010 0.015 0.010 0.010

p,p’-DDE 4 0.0042 0.0051 0.0041 0.0040 chlorpyrifos ethyl 3 0.021 0.023 0.020 0.021

2,4-D 2 0.37 0.40 0.37 0.37
alachlor 2 0.040 0.068 0.027 0.04045 Table 17. Selected pesticide data at S7 and S8 structures before and after Stormwater Treatment Area 3/4 completion.

Ametryn Atrazine Pre-operation Post-operation Pre-operation Post-operation

S7 Average Concentration (μg/L) 0.08 0.05 1.18 0.43

Percent Detections 69 82 87 93

S8 Average Concentration (μg/L) 0.13 0.04 1.31 0.47

Percent Detections 54 64 82 93

Table 18. Sediment pesticide detections fo r Everglades Agricultural Area southern sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg) Threshold
Effect
Concentration (μg/Kg) Probable
Effect
Concentration (μg/Kg) p,p’-DDE 92 29 390 3.2 31 p,p’-DDD 63 15 180 4.9 28 ametryn 48 14 100 - -
PCB-1254 18 124 890 60 680
atrazine 14 14 50 - - p,p’-DDT 14 21 150 4.2 63
chlordane 10 55 190 3.2 18

PCB-1260 8 76 190 60 680
dieldrin 6 7 22 1.9 62
dicofol 3 5.8 9.1 - - diquat 3 1717 2750 - -

PCB-1242 2 67 101 60 680 Italicized values exceed the Threshold Effect Concentration (TEC)
Bold values exceed the Probable Effect Concentration (PEC) - No guideline available46 Figure 16. Urban basin sampling locations.47 Table 19. Surface water pesticide detections fo r urban basin sampling locations from April
1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/L) Maximum
Concentration (μg/L) Concentration
Geometric

Mean Median
Concentration

atrazine 223 0.35 3.3 0.26 0.26 ametryn 149 0.02 0.17 0.02 0.02
atrazine desethyl 76 0.04 0.21 0.03 0.03

hexazinone 48 0.08 1.7 0.04 0.03
atrazine desisopropyl 24 0.020 0.029 0.020 0.021

simazine 15 0.07 0.43 0.05 0.04
diuron 13 0.65 1.4 0.61 0.62 2,4-D 10 7.7 29 5.6 6.8
endosulfan
sulfate 8 0.029 0.11 0.018 0.017

diazinon 7 0.041 0.097 0.61 0.62 alpha
endosulfan 5 0.022 0.076 0.016 0.014

prometon 5 0.029 0.043 0.028 0.023
beta
endosulfan 4 0.026 0.077 0.019 0.026

metolachlor 3 0.09 0.11 0.1 0.1
naled 2 0.22 0.24 0.22 0.22

Table 20. Sediment pesticide detections for urban basin sampling locations from April
1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg) Threshold
Effect
Concentration (μg/Kg) Probable
Effect
Concentration (μg/Kg) p,p’-DDE 47 5.4 21 3.2 31 p,p’-DDD 9 2.5 4.3 4.9 28
bromacil 3 92 200 - -

PCB-1016 2 60 78 60 680 Italicized values exceed the Threshold Effect Concentration (TEC) - No guideline available48 Figure 17. South Miami-Dade County agriculture sampling locations.49 Table 21. Surface water pesticide detections for South Miami-Dade County agriculture sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/L) Maximum
Concentration (μg/L) Concentration
Geometric

Mean Median
Concentration

atrazine 159 0.049 0.4 0.031 0.025 alpha
endosulfan 63 0.014 0.22 0.011 0.010

endosulfan
sulfate 59 0.039 0.45 0.028 0.025

beta
endosulfan 32 0.010 0.078 0.008 0.009

hexazinone 9 0.027 0.052 0.025 0.028
atrazine desethyl 7 0.016 0.033 0.015 0.014

chlorpyrifos ethyl 4 0.035 0.056 0.031 0.028

metolachlor 4 0.11 0.22 0.10 0.10
metribuzin 3 0.11 0.29 0.60 0.30 2,4-D 3 0.95 1.7 0.95 0.95
atrazine desisopropyl 2 0.014 0.016 0.014 0.014

ethion 2 0.037 0.053 0.037 0.03750Figure 18a. Endosulfan detections atS178 from March 1992 to April 1995.

7-Day Antecedent Rainfall, Inches012345growing seasonsampling event7-day antecedent rainfall

Endosulfan in Surface Water, μg/L0.00.10.20.30.40.5growing seasonsampling eventalpha+beta endosulfansulfate62-302 Class III Standard

M ar

- 9 2 Ju

n - 92 Se

p - 92 D ec

- 9 2 M

ar

- 9 3 Ju

n - 93 Se

p - 9 3 D ec

- 9 3 M

ar

- 9 4 Ju

n - 94 Se

p - 9 4 D e c - 9 4 M

ar

- 9 5

Endosulfan in Sediment, μg/Kg020406080100120140growing seasonsampling eventalpha+beta endosulfansulfate51Figure 18b. Endosulfan detections atS178 from June 1995 to July 1998.

7-Day Antecedent Rainfall, Inches012345growing seasonsampling event7-day antecedent rainfall

Endosulfan in Surface Water, μg/L0.00.10.20.30.40.5growing seasonsampling eventalpha+beta endosulfansulfate62-302 Class III Standard

J u n - 9 5 S e p - 9 5 De

c - 9 5 M

a r - 9 6 J u n - 9 6 S e p - 9 6 De

c - 9 6 M

a r - 9 7 J u n - 9 7 S e p - 9 7 D e c - 9 7 M

a r - 9 8 J u n - 9 8

Endosulfan in Sediment, μg/Kg020406080100120140growing seasonsampling eventalpha+beta endosulfansulfate52Figure 18c. Endosulfan detections atS178 from July 1998 to August 2001.

7-Day Antecedent Rainfall, Inches012345growing seasonsampling event7-day antecedent rainfall

Endosulfan in Surface Water, μg/L0.00.10.20.30.40.5growing seasonsampling eventalpha+beta endosulfansulfate62-302 Class III Standard

A ug

- 9 8 N o v - 9 8 Fe

b- 9 9 M

a y - 9 9 A

ug

- 9 9 N ov

- 9 9 Fe

b- 0 0 M

a y - 0 0 A

ug

- 0 0 N ov

- 0 0 Fe

b- 0 1 M

a y - 0 1 A

ug

- 0 1

Endosulfan in Sediment, μg/Kg020406080100120140growing seasonsampling eventalpha+beta endosulfansulfate53Figure 18d. Endosulfan detections at S178 from September 2001 to September 2004.

7-Day Antecedent Rainfall, Inches012345growing seasonsampling event7-day antecedent rainfall

Endosulfan in Surface Water, μg/L0.00.10.20.30.40.5growing seasonsampling eventalpha+beta endosulfansulfate62-302 Class III Standard

S e p - 0 1 De

c - 0 1 M

a r - 0 2 J u n - 0 2 S e p - 0 2 De

c - 0 2 M

a r - 0 3 J u n - 0 3 S e p - 0 3 D e c - 0 3 M

a r - 0 4 J u n - 0 4 S e p - 0 4

Endosulfan in Sediment, μg/Kg020406080100120140growing seasonsampling eventalpha+beta endosulfansulfate54Figure 18e. Endosulfan detections at S178 from September 2004 to December 2007.

7-Day Antecedent Rainfall, Inches012345growing seasonsampling event7-day antecedent rainfall

Endosulfan in Surface Water, μg/L0.00.10.20.30.40.5growing seasonsampling eventalpha+beta endosulfansulfate62-302 Class III Standard

S e p - 0 4 D e c - 0 4 M

a r - 0 5 J un

- 0 5 S e p- 0 5 D e c - 0 5 M

a r - 0 6 J u n- 0 6 S e p- 0 6 D e c - 0 6 M

a r - 0 7 J un

- 0 7 S e p - 0 7 D e c - 0 7

Endosulfan in Sediment, μg/Kg020406080100120140growing seasonsampling eventalpha+beta endosulfansulfate55 Table 22. Sediment pesticide detections for South Miami-Dade County agriculture sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg) Threshold
Effect
Concentration (μg/Kg) Probable
Effect
Concentration (μg/Kg) p,p’-DDE 77 15 89 3.2 31
endosulfan
sulfate 25 16 120 - -

beta
endosulfan 24 5 24 - -

alpha
endosulfan 17 6 30 - -

p,p’-DDD 12 7 15 4.9 28 p,p’-DDT 5 2 3.2 4.2 63
bromacil 3 93 130 - -
ethion 3 10 17 - - Italicized values exceed the Threshold Effect Concentration (TEC)
Bold values exceed the Probable Effect Concentration (PEC) - No guideline available56 Figure 19. Reference basin sampling locations.57 Table 23. Surface water pesticide detections fo r reference basin sampling locations from April 1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/L) Maximum
Concentration (μg/L) Concentration
Geometric

Mean Median
Concentration

atrazine 49 0.052 0.93 0.027 0.019 ametryn 3 0.014 0.018 0.014 0.013

Table 24. Sediment pesticide detections for re ference basin sampling locations from April
1992 to December 2007.

Chemical Number
of
Detections Average
Concentration (μg/Kg) Maximum
Concentration (μg/Kg) Threshold
Effect
Concentration (μg/Kg) Probable
Effect
Concentration (μg/Kg) p,p’-DDE 2 2.8 6.2 3.2 31

PCB-1260 2 21 26 60 680 Italicized values exceed the Threshold Effect Concentration (TEC)