Korovin Lake Investigation

 

This report presents the results of an investigation for small arms ammunition in Korovin Lake in Atka, AK.  The Native Village of Atka and Aleutian Pribilof Islands Association (APIA) prepared the Strategic Project Implementation Plan in 2013 prioritizing this effort because the Tribe is concerned that if small arms ammunition were dumped in Korovin Lake, as suggested may have occurred by historic documents, it could cause water pollution (see www.atkaspip.org). The purpose of this investigation is to define adequate methods to alleviate community concerns if nothing is identified or to identify pollution if it is present. Korovin Lake is the primary source of subsistence salmon in Atka.

The Native American Lands Environmental Mitigation Program (NALEMP) approved the workplan for this investigation in January and the investigation was performed on April 18, 2014.  Investigators included APIA Senior Scientist Bruce Wright, Chilkat Environmental Principal Environmental Scientist Elijah Donat and Captain Alex Zaochney. The methods included dredge sampling, sonar data collection, use of an underwater camera and sampling water for lead and copper.

 

The lake sediment was investigated using a 25-pound dredge at 30 sites along the roaded portion of the lake at varied depths around 20 feet that are otherwise beyond view of lake bottom.  The purpose of dredge sampling was to view the lake sediment to determine if ammunition is observed.  Dredge sampling demonstrated Korovin Lake is very healthy and productive, the sediments are oxygenated and microscope investigation identified an array of large diatoms that dominate the primary production for the lake. No ammunition or debris was discovered.  Observations of the substrate types are presented in Figure 1 and photos of dredge sampling are included below for reference.  The lake bottom has significant deposition of dead algae, sediment and aquatic vegetation.

 

Preliminary investigation was performed October of 2013 and investigators experienced fantastic calm weather that was not repeated for the April 2014 event.  In April underwater camera footage was not productive because an algal bloom reduced visibility. Anomalies on the lake bottom were observed during the fall preliminary investigation but were not again observed during the subsequent spring survey.  It is likely the anomalous readings were adult salmon. Sonar readings were recorded for the dredge samples but no anomalies were observed and the underwater video was not otherwise productive due to wave action and lack of visibility.

Water samples were collected April 18, 2014 and preserved with nitric acid in 500mL poly jars with ice packs maintaining temperature of 4 ± 2 ºC until air shipped out of Dutch Harbor April 24, 2014 and received by the Friedman and Bruya April 28 at 3ºC.  The laboratory report 404501 was prepared May 12, 2014 and the attached Data Quality Review Checklist was prepared May 19, 2014.  Sample locations are presented in Figure 1 and include the outlet with a duplicate as well as the north and south sample.  Samples were collected at multiple depths using a peristaltic pump.

 

Action levels for this project were carefully considered and are the most protective relevant standards for human and ecosystem health.  The lead action level for this project is 15ppb.  This level is based on the maximum contaminant level for EPA Primary Drinking Water Standards. While lead is hazardous to humans, copper is comparatively not.  The Primary National Drinking Water Standard for copper is 1.3ppm.  While copper is relatively non-toxic to humans it is very toxic to anadromous fish and prevents osmoregulation when outgoing juveniles contact saltwater, causing mortality. Therefore, the most protective action level for copper is not the Primary National Drinking Water Standard but rather the Alaska Water Quality Criteria Manual for Toxic and Other Deleterious Organic and Inorganic Substances as amended 2008 in 18AAC 70.020(b)(11).  The action level of 3.1ppb was used for copper because above this level copper has been shown to cause harm to aquatic life in natural systems and in controlled environments such as fish hatcheries.

 

To assure the usefulness of water quality data, the level at which the lead or copper could be measured, the Detection Limit, was set as low as possible.   If no interferences were encountered using EPA method 6020 the detection limit of 0.072ppb for lead and 0.17ppb for copper was our data quality goal.  However, the minimum method detection goal of 1.0ppb for lead and copper is the practical detection benchmark set out in the method and the workplan even if interferences are not encountered.

 

Interferences were encountered in the method blank sample that had measureable lead and copper.  At these very low levels this is common. Despite interference the detection for copper was 0.538 ppb and for lead 0.0461ppb.  These detection levels are satisfactory based on the workplan and method requirements.

 

Copper results were all below our ability to detect copper.  In fact, the method blank used by the laboratory with the most pure water they can make was not as pure as the water in Korovin Lake.  Similarly, of the 10 lead samples, 8 of them were cleaner than the method blank indicating the lake is very clean.  Two samples were positive for lead above the method detection limit goal. These include N-30 at 0.206 and N-10 at 1.13ppb.  N-30 was well below minimum detection goal of 1ppm and was flagged for being reported below normal reporting limits and because lead was detected in the method blank.  The result for N-30 is therefore not reliable and may or may not actually indicate lead presence.  N-10 on the other hand produced a result of 1.13ppb that is not qualified by data quality flags.  This means it’s a real result that is defensible and was definitely present in the sample sent to the laboratory.  The level encountered is thirteen times lower than the action level for this project and is most likely the result of sample contamination. Based on the underwater video observations, we believe the lake is well mixed and that lead is not present in the lake’s water at 10, 20, 30 or 40 feet.  Sampling was performed from a skiff otherwise used for fishing and many potential sources of lead contamination were present.  It is possible that the sampling equipment was contaminated.  If sample N-10 indeed had 1.13ppb lead present, and sample contamination did not occur, the result is still too low to be of concern and does not indicate small arms ammunition is degrading in the lake and causing pollution.  Results are presented in Table 1 below.

 

Sample	Cu	Flag	Project Action Level	MDL goal
S-10	<0.538	j	3.1	0.17
S-20	<0.538	j	3.1	0.17
S-30	<0.538	j	3.1	0.17
S-40	<0.538	j	3.1	0.17
N-10	<0.538	j	3.1	0.17
N-20	<0.538	j	3.1	0.17
N-30	<0.538	j	3.1	0.17
N-40	<0.538	j	3.1	0.17
Out	<0.538	j	3.1	0.17
Out DUP	<0.538	j	3.1	0.17
Blank	0.702	j, lc	3.1	0.17
Sample	Pb	Flag	Pb benchmark	MDL goal
S-10	<0.0461	j	15	0.072
S-20	<0.0461	j	15	0.072
S-30	<0.0461	j	15	0.072
S-40	<0.0461	j	15	0.072
N-10	1.13		15	0.072
N-20	<0.0461	j	15	0.072
N-30	0.206	j, fb	15	0.072
N-40	<0.0461	j	15	0.072
Out	<0.0461	j	15	0.072
Out DUP	<0.0461	j	15	0.072
Blank	0.055	j, lc	15	0.072

Table 1: Laboratory sampling results from FBI Report 404501

j- flag = The result is below normal reporting limits. The value reported is an estimate

lc- flag = Presence of the compound indicated is likely due to laboratory contamination

fb- flag = Analyte present in the blank and the sample

Qualified Environmental Professional, Elijah Donat MS PMP, prepared this 6-page report.