Arsenic and Trace Metals in Common Pesticides in Lake Atitlán, Guatemala By Jansen Costello, Devin Castendyk, Tracy Allen Dept. of Earth & Atmospheric Sciences, SUNY Oneonta, Oneonta, NY 13820

Abstract: Lake Atitlán in Guatemala is the main drinking water source for several communities situated along the shoreline. Studies by SUNY Oneonta show that lake water has dissolved arsenic concentrations of 11-13 µg/L. The World Health Organization’s drinking water guideline for arsenic is 10 µg/L (REF), suggesting that lake water may pose a health risk. This study seeks to determine whether local pesticide use may contribute to observed arsenic levels. The watershed surrounding Lake Atitlán is heavily used for agriculture. Farmers apply pesticides to crops in order to increase yields. These pesticides many contain inorganic constituents which are harmful to humans at high concentrations, such as arsenic, copper, and mercury. Rain rinses these constituents from corps and into streams, which then flow into the lake. This experiment measured the composition of the four most common pesticides used in the watershed which we purchased from a farm supply store in Sololá in 2014, plus two unknown pesticides collected from farmers. We prepared these solution at SUNY Oneonta and submitted them to Actlabs in Ontario for ICP-MS, ion chromatography, and FIMS analysis. By testing each pesticide for 70 parameters, we will define their geochemical signature, and evaluate their contribution to arsenic in lake water.

Purpose:

The purpose of this study is to measure the composition of metals dissolved in common pesticides used around Lake Atitlán, and to compare these concentration to lake water concentrations. This will identify potential sources of metals to the lake.

Methods: The following procedure was used to measure metals and other dissolved solids in common pesticides: (1) Purchase four common pesticides in a local pesticide shop in Sololá, Guatemala in June 2014 (Table 1). (2) In New York, translation of the preparation methods on pesticide bottles from Spanish to English, followed by a phone conversation with each company. (3) Clean all glass wear in dilute nitric acid bath. (4) Make solutions of the four pesticides in one liter flasks. Table 1 shows the pesticides, the preparation instructions, images of prepared solutions, and the active ingredients listed on the bottle. (5) Measure pH and electrical conductivity of each pesticide (Table 1). (6) Submit a 60 mL sample of each pesticide to Actlabs, Ancaster, Ontario for trace-metal analysis by Inductively Cuppled Plasma -Mass Spectrometer (ICP-MS), mercury analysis by FIMS, and anion analysis by Ion Chromatograph. (7) Compare pesticide concentrations to observed surface water chemistry in Lake Atitlan in May 2014.

Conclusions: Data from Actlabs, shows that the four different pesticides contain many different amounts of heavy metals and solvents. The most interesting heavy metals and solvents were As, Mn, Cr, Cu, Co, and Zn. Arsenic, our main concern of the lake, was found to be less concentrated in the pesticides then the lake itself. This implies that high levels of arsenic in the lake is most likely not from pesticides being spread on local farms. Each pesticide had its own unique composition when it came to heavy metals. All of the pesticides were very different when compared to water found in Lake Atitlán. Rival was very high in copper (2 µg/L), Tambo 44 EC was elevated in Manganese (3.2 µg/L) and Zinc (19.5 µg/L), and Totem 72 SL was concentrated in Cobalt (0.121 µg/L). Yet surprisingly Super Herbaxon 20 SL lacked heavy metals when compared to the rest of the pesticides. A source is any origin that has a higher concentration than the lake itself. The data shown above shows that Rival, Tambo 44 Ec, and Totem 72 Sl all have potential to be sources of heavy metals for Lake Atitlán. Yet, these three pesticides also show that they are not sources of high levels of Arsenic in Lake Atitlán. In order to expand out knowledge and data for this topic we need to return back to Guatemala. Once in Guatemala we can run more accurate data testing by picking specific farms that utilize the pesticides above. Students can then follow the movement of the pesticides from the source of the farm, down to the stream or river, and then its movement throughout the rivers till they reach Lake Atitlán. As for the arsenic we need to look for other sources and origins. Yet until then, we can interpret that high levels of heavy metals are coming from agricultural land that is surrounding Lake Atitlán.

Background:

Lake Atitlán, locally known as Lago de Atitlán, is located in the middle of the Guatemalan Highlands of the Sierra Madre mountains (Figure 1, 2, 3). Lake Atitlán is part of the Sololá department of northern Guatemala. In Nahuatl, Atitlán means "at the water." With a maximum depth of 340 m, Lake Atitlán is the deepest lake in Central America. The area is 12 x 5 km, and it can hold up to 20 km² of water (Cultural

Tour, 2014). The lake is an extremely important water source to the indigenous Mayan population surrounding the lake. There are nine main villages that surround Lake Atitlán: Panajachel, Santa Catarina, San Antonio, Santa Cruz la Laguna, El Jaibalito,

Tzununá, San Marcos la Laguna, San Pedro la Laguna, and Santiago Atitlan (Atitlan Community, 2015). These villages depend on this water source because they have municipalities that utilize and consume water from the lake every day. Knowing that this lake contains high levels of arsenic and other heavy metals, may pose a threat to the indigenous Mayan population in the future. Agriculture is a large part of the Mayans lifestyle and is the main income for 95% of

the Mayan population(Cultural Tour, 2014; Fig. 4 and 5). The main four crops grown for this area are coffee, avocado, corn, and onions. Other important crops grown in this area are: beans, squash, tomatoes, cucumbers, garlic, chile verde, strawberries and pitahaya fruit. Farmers often apply pesticides on to crops using sixteen-liter sprayer backpack (Figure 6). The process evenly applies the pesticide by hand to the crops in order to minimize cost.

References: "A Cultural Tour of Lake Atitlan and Chichicastenango Market." Escape the Ordinary. N.p., 23 Apr. 2014. Web. 13 Apr. 2015. "Air Pollution in Developing Countries." Air Pollution in Developing Countries. N.p., n.d. Web. 13 Apr. 2015. Drugs.com. “Arsenic Trioxide Side Effects in Detail – Drugs.com.” Arsenic Trioxide Side Effects in Detail – Drugs.com. Drugs.com, n.b. Web. 06 Nov. 2014. EPA. "Arsenic in Drinking Water." Home. EPA, n.d. Web. 12 Nov. 2014. "Lake Atitlan, Guatemala." Lake Atitlan Community. N.p., 13 Apr. 2015. Web. 13 Apr. 2015. Morgan Szybist, Richard (2004), The Lake Atitlan Reference Guide:The Definitive Eco-Cultural Guidebook on Lake Atitlan Adventures in Education, Inc. University of Nevada, Reno. "US AID Project Fact Sheet." US AID Project Fact Sheet (2011): n. pag. Web. World Health Organization. "Arsenic." WHO. World Health Organization, n.d. Web. 10 Nov. 2014.

Figure 5: Corezon de Bosque. Taken by Devin Castendyk.

Figure 4: Concepcion, Guatemala. Taken by Devin Castendyk.

2

0.7 0.5

0.702

0.1

1

10

Rival Tambo 44 EC

Totem 72 SL

Super Herbaxon

20 SL

Lake Atitlán

Mic

rogr

am p

er L

iter

- µ

g/L

Copper (Cu)

1.9

19.5

8.6

1.6 1.2

1

10

100

Rival Tambo 44 EC

Totem 72 SL

Super Herbaxon

20 SL

Lake Atitlán

Mic

rogr

am p

er L

iter

- µ

g/L

Zinc (Zn)

1

7.4

4.9

6.9 9.5

1

10

Rival Tambo 44 EC

Totem 72 SL Super Herbaxon

20 SL

Lake Atitlán

Mic

rogr

am p

er L

iter

- µ

g/L

Chromium (Cr)

0.067 0.036

0.121 0.076 0.059

0.01

0.1

1

Rival Tambo 44 EC

Totem 72 SL

Super Herbaxon

20 SL

Lake Atitlán

Mic

rogr

am p

er L

iter

- µ

g/L

Cobalt (Co)

0.5

3.2

1.5 0.8

0.21

0.1

1

10

Rival Tambo 44 EC

Totem 72 SL

Super Herbaxon

20 SL

Lake Atitlán

Mic

rogr

am p

er L

iter

- µ

g/L

Manganese (Mn)

Acknowledgements: Special thanks to Dr. Elizabeth Smalls, Spanish Department Chair, for translating and assisting out of country calls to pesticide companies. Special thanks to Students from GEOL 385 Water Resource of Guatemala, 2014, for collecting all data from Lake Atitlán and purchasing pesticides from local store. Special thanks to Oneonta student grant program for research and creative activity for funding a grant in order for me to complete this project.

Figure 3: Lake View of Lake Atitlán. Taken by Devin Castendyk.

Figure 2: Map of Lake Atitlán

Figure 1: Map of Guatemala

Figure 6: Farmer applying pesticides to crops.

Image Pesticide Name

Manufacturer Solution pH Electric Conductivity (µS/cm)

Rival Duwest, Honduras

50g per 16 L

4.13 1198

Tambo 44 EC Disagro, Guatemala

25 ml per 3.2 L 3.28 249

Totem 72 SL Duwest, Honduras

125 ml per 16 L

7.98 1869

Super Herbaxon 20 SL

Duwest, Costa Rica

125 ml per 16 L 4.55 2260

Figure #7

Table #1

0.56 0.79

0.07

13.38

0.01

0.1

1

10

100

Rival Tambo 44 EC

Totem 72 SL

Super Herbaxon

20 SL

Lake Atitlan M

Icro

gram

per

Lit

er -

µ

g/L

Arsenic (As)