Influence of Landcover, Rainfall, and River Flow on ... - ACS Publications

Downloaded by PURDUE UNIV on February 15, 2016 | http://pubs.acs.org Publication Date (Web): September 22, 2014 | doi: 10.1021/bk-2014-1168.ch007

Chapter 7

Influence of Landcover, Rainfall, and River Flow on the Concentration of Pyrethroids in the Lower American River, Sacramento, California, United States Christopher M. Harbourt,*,1 Gregory E. Goodwin,1 Stephen L. Clark,2 Drew Gantner,2 Bradley A. Sliz,1 Todd Albertson,3 Michael Dobbs,,4 Kevin Henry,5 and Gary Mitchell6 1Waterborne

Environmental, Inc., 897-B Harrison Street, SE, Leesburg, Virginia 20175, United States 2Pacific EcoRisk, 2250 Cordelia Road, Fairfield, California 94534, United States 3Caltest Analytical Laboratory, 1885 N. Kelly Rd., Napa, California 94558, United States 4Bayer CropScience LP, 2 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States 5Syngenta Crop Protection, 410 Swing Rd., Greensboro, North Carolina 27409, United States 6FMC Agricultural Products, Building 100, Charles Ewing Boulevard, Ewing, New Jersey 08628, United States *E-mail: [email protected]

A multi-site, spatio-temporal transect study on the Lower American River was conducted to systematically investigate the influence of agricultural and urban landcover, river flows and rainfall events on the concentration of pyrethroids. The majority of the flow in this section of the river throughout the year is controlled discharge from Folsom Dam. Local storm drains, small ephemeral channels and an extensive network of organized storm drain collection and pump stations discharge excess rainfall from surrounding urban and suburban © 2014 American Chemical Society In Describing the Behavior and Effects of Pesticides in Urban and Agricultural Settings; Jones, Russell L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2014.


environments into the Lower American River channel. Rainfall event-driven sampling was carried out during the 2011-2012 and 2012-2013 rainy seasons for eight pyrethroids. Results indicate that rainfall-runoff events are the driving perturbations behind the infrequent and highly variable pyrethroid movement into the Lower American River. A variety of factors contribute to environmental complexity. However, rainfall is the only true driver, while other land cover complexities, stormwater detention systems, and hard surfaces contribute to the variability in local rainfall-runoff contribution to river flows.

Introduction Pyrethroids are a class of insecticides used to control a wide range of pests in both agricultural and urban settings. Pyrethroid use in urban areas has increased since the registration of organophosphate insecticides for urban uses has been withdrawn. California is an area where pyrethroids are used extensively and have been detected in the sediments of urban creek (1–3). The Pyrethroid Working Group (PWG) is completing a larger program of studies to better understand the critical factors governing the fate and transport of pyrethroids in urban areas. This study is part of that larger program, and is designed to build upon the findings of recent studies which examined pyrethroid residues in grab samples collected from along the bank of the American River (3). Whereas the aforementioned studies prescribed subjective point sampling of the American River, there was a need to develop a larger scale, more comprehensive sampling approach for the river for a thorough examination of factors which may influence pyrethroid concentrations. The larger scale monitoring program would allow for the investigation of pyrethroid concentrations in the context of a greater distribution of rain events and river flow conditions – both major potential driving forces in the movement of pyrethroids. The larger scale program would also include improved sampling techniques that can be used to answer basic questions about variability in pyrethroid concentrations within river flows and in different portions of the river. Developing a sound sampling strategy is a crucial step in understanding the occurrence of pyrethroids in the American River; and elucidating the relationship between pyrethroid detections with rainfall and river flow.

Sampling and Analysis Techniques The following sections describe the study area, identify the analysis techniques used to select and sample transects of the river, and describe how river samples at various river conditions were obtained.

154 In Describing the Behavior and Effects of Pesticides in Urban and Agricultural Settings; Jones, Russell L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2014.


Study Area The American River is a large river system with a watershed that stretches from a portion of the Sierra Nevada mountains near Lake Tahoe down into the Central Valley eventually draining into the Sacramento River at Sacramento, California. The upper watershed drains primarily undisturbed forest land east of Folsom Lake. As the river flows west, the watershed land area drastically shifts into an agriculturally dominated land cover that transitions to highly urbanized near the outlet of the lower American River and into the Sacramento River. Based on previous monitoring (3), the waters in the upper reaches of the river system have been shown to be typically free of pyrethroids. However, Weston and Lydy (3) reported that the lower river reach at times contained pyrethroid residue concentrations in water samples at levels potentially harmful to the aquatic toxicity indicator species, Hyallela azteca (Range of detections: 1.2 – 5.6 ng/L Bifenthrin, 5.0 ng/L Permethrin). The detections of pyrethroid are likely the result of suburban and urban uses and higher human population density within the lower watershed (Figure 1).

Figure 1. Population density distribution throughout the lower American River Watershed. (see color insert)

Seven locations were selected to conduct transect sampling under a variety of conditions. A list of the transect descriptions and geographic locations corresponding to Figure 1 can be found in Table I.


Table I. Transect Descriptions and Locations


Site Name

Description

Latitude

Longitude

ARDLN

Downstream of Lake Natoma

38.636542

-121.218436

ARSAB

Sunrise Avenue Bridge

38.632275

-121.270653

ARWAB

Watt Avenue Bridge

38.566867

-121.382994

ARCSR

Downstream of the Chicken Ranch / Strong Ranch Slough storm drain discharge point

38.583633

-121.424472

ARB80

Upstream of Business 80 Bridge

38.587156

-121.446647

ARDPK

Discovery Park upstream of Sacramento River

38.602300

-121.489444

ARSOE

Downstream of Sump 11 storm drain discharge point

38.602636

-121.496686

Table II summarizes the developed land fraction for each transect-based subcatchment in the watershed, as defined by the USDA Cropping Data Layer (CDL) which also accounts for non agricultural land uses.

Table II. Developed Land Fraction for Subcatchments Associated with Each Transect Location in Order from Farthest Upstream to Farthest Downstream Transect

Developed Land Fraction

ARSAB

42%

ARWAB

64%

ARCSR

75%

ARB80

75%

ARDPK

69%

ARSOE

69%

In Table II, all transects except ARSAB contain relatively high (>50%) developed land fractions. The city of Sacramento falls within this part of the watershed with heavy development near the confluence with the Sacramento River. A further illustration of the watershed area that contributes to the river transect locations can be seen in Figure 2. The developed land fraction percentage for each transect moving downstream represents not only the additional area shown for each transect, but also the sum of the watershed area upstream of it, excluding the watershed area upstream of Lake Natoma. This watershed area was excluded to highlight the portion of developed area in the lower watershed that provides runoff directly to the river and is not buffered by the upstream reservoirs/lakes. 156 In Describing the Behavior and Effects of Pesticides in Urban and Agricultural Settings; Jones, Russell L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2014.


Figure 2. Individual cross-section delineations. (see color insert) Watershed Hyrdrology The lower American River is a highly managed river system controlled by a series of dams and prescribed discharges to meet various river flow criteria. Folsom Lake is a significant impoundment covering approximately 46 sq-km followed closely downstream by the relativley narrow Lake Natoma covering 2 sq-km but stretching more than 22 km in length. The lower American River begins at the outfall from Lake Natoma. Seasonally flows vary as dam discharges upstream vary, but they typically do so to meet seasonal prescribed discharge ranges that are not nessesarily linked to recent (last few days) rainfall trends. Instead, variations in flow of the lower American River during rainfall events are more a function of the suburban and urban free-flowing side channels and pumped discharges of stormwater. Although these urban discharges do account for variation, the range of baseflows delivered by the upstream dam releases account for the majority of river flow even on days of significant rainfall in the lower American River watershed (4). Overall Study Design In this multi-year study, the first year sampling covered rainfall events, event flows, and dry condition flows using discrete samples laterally and vertically within the river, at a number of cross-sections scattered through the lower American River. Second year sampling focused on rainfall event sampling only and depth integrated samping at more locations laterally in each identified cross-section. Changes in the second year were based on the nature and residue detection distribution of sampling results in year one. 157 In Describing the Behavior and Effects of Pesticides in Urban and Agricultural Settings; Jones, Russell L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2014.


2011-2012 Monitoring Design Year one (2011-2012) monitoring consisted of an approach designed to examine residues in the water column and bed sediment for determination of overall pyrethroid presence. “Wet” (rainfall driven) and “Dry” (non-rainfall driven) events were sampled. “Wet” event monitoring was conducted the first full day following a precipitation exceedence threshold of 7.6 mm occurring in a period of 24 hours throughout the majority of the lower American River watershed. “Dry” events were declared as monitoring occurring at least one week after the last precipitation. “Dry” event monitoring was conducted on three separate occasions, once at the beginning of the rainy season (late October – early November), once mid-rainy season (mid January), and once at the end of the rainy season (late May – early June).

Water Samples A representative transect sample consisted of several discrete stations each consisting of several disctete depth samples. The wetted width of the channel at the sampling location was estimated and divided into five approximately equal segments, representing the distance between each sampling station along a transect perpendicular to the flow of the river. The first sample location was located at one half of one segment width from the right bank (1/10th of the distance across the channel). The subsequent sampling locations were positioned at 30%, 50%, 70%, and 90% of the distance across the channel from the right bank. Samples were collected from three discreet depths at each sampling station: 1’ below the water surface, mid channel depth, and 1’ above the bottom of the channel. However, depending on the water depth at each sampling location, not all of the samples may have been collected based on the following practical sample collection guidance: a) dry – no water means no water sample b) MDL1

% of Samples > RL1

Range > RL (ug/L)

Cross Sections with Detected Pyrethroids

Bifenthrin

60.0

33.3

0.34–5.3

ARDLN, ARWAB, ARCSR, ARDPK, ARSOE,

Cyfluthrin

20.0

6.7

0.55–0.55

ARCSR, ARDPK, ARSOE

Cypermethrin

20.0

0.0

---

ARCSR, ARB80, ARDPK

Deltamethrin: Tralomethrin

6.7

6.7

1.3–1.3

ARDPK

Efenvalerate: Fenvalerate

0.0

0.0

---

---

Fenpropathrin

0.0

0.0

---

---

LambdaCyhalothrin

13.3

6.7

0.79–0.79

ARB80, ARDPK

Permethrin

20.0

20.0

1.9–4.3

ARDLN, ARCSR, ARDPK

Percentages out of 15 total samples collected.


Table X. Pyrethroid Detection for the Post-“Rainy” Season Bed Sediment Sampling Event on May 21, 2012 % of Samples > MDL1

% of Samples > RL1

Range > RL (ug/L)


Bifenthrin

64.3

21.4

1.5–1.7

ARDLN, ARDPK, ARSOE

Cyfluthrin

14.3

7.1

0.82−0.82

ARDPK, ARSOE

Cypermethrin

7.1

0.0

---

ARDPK

Deltamethrin: Tralomethrin

0.0

0.0

---

---

Efenvalerate: Fenvalerate

0.0

0.0

---

---

Fenpropathrin

0.0

0.0

---

---

LambdaCyhalothrin

14.3

0.0

---

ARDPK, ARSOE

Permethrin

14.3

7.1

4.7–4.7

ARDPK


Analyte

1


Other Events As the results of the first year of monitoring suggested the presence of pyrethroid residues in the river sysem as a result of storm events, additional monitoring studies were proposed during the second year of the study. Three alternative types of monitoring studies were targeted to address questions regarding pyrethroid residue persistence as a result of storm events. Two of the additional studies were employed during the sampling event that took place on March 20, 2013. The first study during this span was the Lagrangian/ Drift style sampling method used to sample between the ARCSR and ARB80 cross-sections. This river reach was chosen based on a history of more frequent detections due to the ARCSR cross-section proximity to the Chicken Ranch/Strong Ranch slough discharge into the river. The results of this sampling study are highlighted in Table XI.


Table XI. Intertransect Drift Study Detection Summary for March 20, 2013 % of Samples > MDL1

% of Samples > RL1

Range > RL (ng/L)

Bifenthrin

97.9

2.1

1.5–1.5

Cyfluthrin

0.0

0.0

---

Cypermethrin

0.0

0.0

---

Deltamethrin:Tralomethrin

2.1

0.0

---

Efenvalerate:Fenvalerate

0.0

0.0

---

Fenpropathrin

0.0

0.0

---

Lambda-Cyhalothrin

0.0

0.0

---

Permethrin

0.0

0.0

---


Analyte

1




The results of this monitoring event only yielded one sample with a concentration above the reporting limits, which was for bifenthrin detected at a level of 1.5 ng/L. However, bifenthrin was detected at levels between the method detection limit (MDL) and reporting limit (RL) in nearly 98% of samples collected. A spatial view of these data is provided in Figure 4.

Figure 4. Concentration values and velocity during the inter-transect study on March 20, 2013. (see color insert) The second study conducted on March 20, 2013, was the revisiting of a single transect to address persistence of pyrethroid residues at a single transect. Two bank to bank samplings of the transect were conducted similar to other “Wet” sampling events. The overall summary of the detections found during this study are provided in Table XII. This sampling study also yielded a high frequency of bifenthrin detections; however, all detections were between the MDL and RL. Single detections of all other analytes except permethrin were also found, but again at concentrations below the RL. In general, concentrations between the first and second traverse of the sampling transect were fairly consistant, however, all either remained the same, or declined between the first and second sampling pass; the greatest difference in any single concentration a sampling location being only 0.4 ng/L. This result was somewhat expected, however, because of the relatively short time period that elapsed between the first and second pass across the transect (approximately 1 hour). Even so, relatively little data exists regarding duration of residue persistence. 172 In Describing the Behavior and Effects of Pesticides in Urban and Agricultural Settings; Jones, Russell L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2014.

Table XII. Transect Revisit Sampling at ARB80 on March 20, 2013 % of Samples > MDL1

% of Samples > RL1

Range > RL (ng/L)

Bifenthrin

100.0

0.0

---

Cyfluthrin

5.6

0.0

---

Cypermethrin

5.6

0.0

---


5.6

0.0

---


5.6

0.0

---

Fenpropathrin

5.6

0.0

---

Lambda-Cyhalothrin

5.6

0.0

---

Permethrin

0.0

0.0

---


Analyte

1


The third alternative sampling study consisted of multiple transect revisits over a three day period between June 24–26, 2013 during a “Wet” event. These events were monitored in the same way as the “Wet” events and the transect revisit sampling at the ARB80 transect; however, monitoring was only conducted at a subset of transects. This event consisted of sampling the ARCSR and ARB80 transects on all three days of monitoring, and the ARCSR cross-section twice on the second day. Additionally, ARDPK and ARSOE transects were sampled on the second day as well. The summary of detections can be seen in Table XIII.

Table XIII. Detections During Multi-Day Monitoring Event June 24–26, 2013 % of Samples > MDL1

% of Samples > RL1

Range > RL (ng/L)


Bifenthrin

6.2

1.2

4.8–4.8

ARB80, ARCSR, ARDPK

Cyfluthrin

1.2

1.2

2.5–2.5

ARDPK

Cypermethrin

0.0

0.0

---

---


0.0

0.0

---

---


0.0

0.0

---

---

Fenpropathrin

0.0

0.0

---

---

Lambda-Cyhalothrin

0.0

0.0

---

---

Permethrin

0.0

0.0

---

---

Analyte

1



Very few detections were found during this monitoring event and no detections were observed on either day one or three of the event. Only 5 samples collected over the three day period yielded detectable concentrations. All 5 samples contained detectable concentrations of bifenthrin, however, only one was over the reporting limit. This same sample also contained cyfluthrin above the reportable limit.


Conclusions The data collected and analysis conducted during this multi-year study identified rainfall-runoff events are the driving perturbations behind the infrequent and highly variable pyrethroid movement into the lower American River. A variety of factors contribute to environmental complexity. However, rainfall is the only true driver, while other land cover complexities, stormwater detention systems, and hard surfaces contribute to the variability in local rainfall-runoff contribution to river flows. Additionally these local rainfall-runoff flows are small relative to the much larger controlled dam releases upstream from larger lake storage. Among these complexities, it is clear that river base flow and rainfall event timing both play critical roles in determining the presence, persistence, and magnitude of pyrethroid residues. Due to these factors, and in addition to receiving water characteristics, assessments of this waterway cannot be based on selective point sampling near a river bank. As the results of this study suggest, heterogeneity among river cross-sections and reaches require a more robust sampling regime, such as the one implemented during this study. Through such study design, the dynamics of pyrethroid concentrations in this waterway can be investigated and results to date demonstrate that pyrethroid residues have generally been low and infrequent. The range across the combination of river base flow, dry periods, and significant rainfall-runoff conditions monitored during this study are extensive, but not exhaustive. The range monitored, however, does represent a significant portion of the conditions typically experienced in this watershed. In an attempt to target a larger range of river and rainfall conditions to provide a more comprehensive data set, this study has continued into the 2013–2014 rainy season.

References 1.

2. 3.

4.

Weston, D. P.; Holmes, R. W.; You, J.; Lydy, M. J. Aquatic toxicity due to residential use of pyrethroid insecticides. Environ. Sci. Technol. 2005, 39, 9778–9784. Weston, D. P.; Holmes, R. W.; Lydy, M. J. Residential runoff as a source of pyrethroid pesticides to urban creeks. Environ. Pollut. 2008, 157, 287–294. Weston, D. P; Lydy, M. J. Urban and agricultural sources of pyrethroid insecticides to the Sacramento-San Joaquin Delta of California. Environ. Sci. Technol. 2010, 44 (5), 1833–1840. Williams, J. G. Chinook salmon in the lower American River, California’s largest urban stream. Fish. Bull. 2001, 174, 1–38. 174

In Describing the Behavior and Effects of Pesticides in Urban and Agricultural Settings; Jones, Russell L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2014.

5.

6.

7.


8.

ASTM Standard D1193-06: Standard Specification for Reagent Water; ASTM International: West Conshohocken, PA, 2011, DOI: 10.1520/D119306R1, http://www.astm.org. Edwards, T. K.; Glysson, G. D. Field Methods for Measurement of Fluvial Sediment; Techniques of Water Resources Investigations; U.S. Geological Survey: Reston, VA, 1999, b.3, c.C2, p 89. Clesceri, L. S. Standard Methods for the Examination of Water and Wastewater, 20th ed. revised; American Public Health Association: Washington, DC, 1998. Doc. #: O-PyrethroidsNCI-rev3a; Caltest Analytical Laboratory, 2012.


Influence of Landcover, Rainfall, and River Flow on ... - ACS Publications

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