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HEALTH CONSULTATION

Response to Community Inquires Regarding Nitrate, Lead, Thallium and Chromium Levels in Water from Private Domestic Wells near the Pacific Gas and Electric Facility in Hinkley, California

PACIFIC GAS AND ELECTRIC FACILITY
HINKLEY, SAN BERNARDINO COUNTY, CALIFORNIA


SUMMARY

In August 2001, the Environmental Health Investigations Branch (EHIB) of the California Department of Health Services (CDHS) was asked by the Lahontan Regional Water Quality Control Board (Lahontan RWQCB) to review and provide a public health interpretation of sampling results for 25 private domestic wells in Hinkley, California. These wells are located around the area of groundwater that has been contaminated with chromium by the Pacific Gas & Electric (PG&E) gas compressor station. Three of the wells belonging to one property owner had elevated levels of nitrate, lead, and thallium. EHIB sent letters explaining the health implications of the sampling results to the two residents and one property owner whose homes were served by the three wells (see Appendices A-C). EHIB also responded to follow-up inquiries from the property owner (see Appendix D). The content of these letters is the basis of this health consultation. EHIB has a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR) and this health consultation is being forwarded to ATSDR for their concurrence.


BACKGROUND AND STATEMENT OF ISSUES

In December 2000, EHIB completed a public health assessment of exposures from the PG&E gas compressor station, in which EHIB recommended that the Lahontan RWQCB sample private domestic wells located around the chromium-contaminated groundwater for total chromium and hexavalent chromium. In August 2001, the Lahontan RWQCB sampled 25 private domestic wells and had the water analyzed for total and hexavalent chromium. In order to improve their understanding of the quality of the groundwater, the Lahontan RWQCB also had the water analyzed for other metals and minerals that are regulated in public drinking water systems. The well water samples were not analyzed for coliform. EHIB reviewed the results of these tests and compared the levels of contaminants to drinking water standards. The levels of total chromium did not exceed the drinking water standard; however, three wells, located on contiguous properties, had levels of nitrate, lead, and thallium that exceeded drinking water standards.


DISCUSSION

The following is a summary of the total chromium, nitrate, lead and thallium findings, as well as the pertinent information that was included in the letters to the residents and property owner (for more detail refer to Appendices A-D). Copies of the laboratory reports for the chromium and other metals were included with each letter.

Public Health Interpretation of Private Well Sampling Results

Total and Hexavalent Chromium

None of the private domestic wells sampled by Lahontan RWQCB had levels of total chromium above California's drinking water standard (50 micrograms per liter (µg/L); US Environmental Protection Agency's standard is 100 µg/L). There is no drinking water standard for hexavalent chromium. The levels of total and hexavalent chromium in the three wells ranged from 4 µg/L to 6 µg/L and non-detect, respectively. The letters EHIB sent to the residents and property owner provided the results of the total and hexavalent chromium analyses and explained that no health effects were expected to result from the levels measured in their water. EHIB included a copy of the laboratory results for the chromium tests as well as a fact sheet on "Chromium in Drinking Water" that was developed jointly by the CDHS Division of Drinking Water and Environmental Management and the California Environmental Protection Agency Office of Environmental Health Hazard Assessment (see Appendix E).

Nitrate

Two of the three wells had nitrate levels above the drinking water standard (10 milligrams per liter (mg/L)). The levels of nitrate in these wells ranged from 12 mg/L to 24 mg/L. EHIB's letters to the residents described the susceptibility of pregnant women and formula-fed infants to nitrate. EHIB also provided a fact sheet on "Health Concerns Related to Nitrate and Nitrite in Private Well Water" (see Appendix F). Though the source of the nitrate contamination is currently unknown, community members were informed of typical sources of nitrate contamination, namely agricultural and dairy farms.

Lead

All three wells had lead levels above the drinking water standard (0.015 mg/L). The levels of lead ranged from 0.079 mg/L to 0.100 mg/L. In the letters to the residents, EHIB described the susceptibility of children to lead poisoning, provided contact information for childhood blood lead tests, and included two information brochures on childhood lead poisoning (see Appendices G and H). Though the source of the lead contamination is currently unknown, EHIB provided information on possible sources of lead contamination.

Thallium

One of the three wells was sampled and tested twice. On one of the sampling occasions, the level of thallium was 0.19 mg/L, which is above the drinking water standard (0.002 mg/L). In the letter to the one resident and well owner, EHIB described the health effects of thallium, and discussed possible sources of thallium contamination. The definite source of the thallium contamination is currently unknown.

Follow-Up Testing

During the week of September 24, 2001, the Lahontan RWQCB sampled the three wells for confirmation testing. The Lahontan RWQCB provided the residents and property owners with the results of these tests.

Request for Information from Hinkley Resident

EHIB staff responded on the telephone and in writing to a follow-up inquiry from the property owner. The following section summarizes EHIB's telephone discussions with and follow-up letter to the resident (see Appendix D).

Review of 1994 Well Test Results

The property owner had three wells tested in 1994 and informed EHIB that no contaminants were measured above the primary drinking water standards. If the proper analytic methods were used, this historical information on water quality is useful to Lahontan RWQCB's work to protect the quality of underground water resources.

How the Water Quality Might Affect Animals

The property owner was concerned about the safety of the water for their animals (horses, cows, dogs and cats). EHIB consulted with the California Animal Health and Food and Safety Laboratory to learn the maximum recommended drinking water levels of nitrate, lead and thallium. The level of lead in all three wells is within the maximum recommended range. The levels of nitrate and thallium measured in one sample of one of the wells are higher than the maximum recommended levels for livestock.

Where the Contamination Came From

The definite sources of the nitrate, lead and thallium contamination are currently unknown. Nitrate is a common contaminant in agricultural and dairy areas; the sources of the lead and thallium contamination are more difficult to identify. The Lahontan RWQCB is responsibility for monitoring and protecting the quality of underground water resources in the Hinkley area.

Water Treatment Options

No store-bought water filters or treatment systems are certified to reduce the levels of nitrate, lead or thallium measured in the three wells to below the drinking water standard. However, there are some professionally-installed water treatment systems that can substantially reduce the level of contamination. Contact information for local water treatment professionals was provided.


CONCLUSIONS

The levels of total chromium measured in the 25 private domestic wells are below the drinking water standard and do not pose a health risk. The levels of nitrate in two of the three wells are above the drinking water standard. All three wells exceed the drinking water standard for lead. And, one of two sampling occasions, the level of thallium in one of the three wells exceeded the drinking water standard. Consumption of water from these three wells may pose a health hazard, particularly to children (due to lead contamination) and pregnant women and formula-fed infants under the age of 6 months (due to nitrate contamination).


PUBLIC HEALTH ACTION PLAN

The Public Health Action Plan (PHAP) for this site contain a description of actions taken, to be taken, or under consideration by ATSDR and EHIB at and near the site. The purpose of the PHAP is to ensure that this health consultation not only identifies public health hazards, but also provides a plan of action designed to mitigate and prevent adverse human health effects resulting form exposure to hazardous substances in the environment. EHIB and ATSDR will follow-up on this plan to ensure that actions are carried out.

Actions Completed:

  1. EHIB informed Hinkley residents of the results and health implications of the private domestic well testing performed by Lahontan RWQCB.


  2. EHIB recommended that water from the three wells not be used for drinking or cooking. Water from the well with a one-time elevated thallium level should not be used to water fruit or vegetable gardens.


  3. EHIB recommended that water from the well with elevated thallium not be fed to animals.


  4. EHIB informed residents that store-bought water filters are not certified to meet drinking water standards, but some professional water treatment systems can substantially reduce the level of contamination.


  5. EHIB informed residents that private wells are not regulated or tested by the state and that the owners of these wells are responsible for making sure that the water is safe to consume.


  6. EHIB informed residents that their water was not tested for coliform, one of the more common water contaminants.


  7. EHIB recommended that the property owner send a copy of the results of the 1994 water test to EHIB (to review test methods) and to the Lahontan RWQCB.


  8. EHIB recommended that the property owner contact Lahontan RWQCB to convey their concerns about the nitrate, lead and thallium contamination.

Recommendation:

  1. EHIB recommended that private well owners test their wells on a regular basis for chemicals, metals, minerals and bacteria that may be present in underground water at levels injurious to health.

PREPARERS OF REPORT

Environmental and Health Effects Assessors

Jackie Schwartz, MPH
Environmental Health Scientist
Environmental Health Investigations Branch
California Department of Health Services

Tracy Barreau, REHS
Environmental Health Scientist
Environmental Health Investigations Branch
California Department of Health Services


ATSDR Regional Representatives

William Nelson
Gwendolyn Eng
Libby Levy
Regional Representatives, Region IX
Agency for Toxic Substances and Disease Registry


ATSDR Technical Project Officer

Tammie McRae, M.S.
Environmental Health Scientist
Division of Health Assessment and Consultation
Superfund Site Assessment Branch, State Programs Section


CERTIFICATION

This Response to Community Inquiries Regarding Nitrate, Lead, Thallium and Chromium Levels in Water from Private Domestic Wells Near the Pacific Gas & Electric Facility in Hinkley, California was prepared by the California Department of Health Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with the approved methodology and procedures existing at the time the health consultation was begun.

Tammie McRae, M.S.
Technical Project Officer
Superfund Site Assessment Branch (SSAB)
Division of Health Assessment and Consultation (DHAC)
ATSDR


The Division of Health Assessment and Consultation, ATSDR, has reviewed this health consultation, and concurs with its findings.

Roberta Erlwein
Chief, SPS, SSAB, DHAC, ATSDR


APPENDIX A: LETTER TO HINKLEY COMMUNITY MEMBER

To: Hinkley Community Member
Re: Results of Private Well Testing
From: The California Department of Health Services
Date: September 14, 2001


DEPARTMENT OF HEALTH SERVICES
1515 CLAY STREET, SUITE 1700
OAKLAND, CA 94612
(510) 622-4500


September 14, 2001

Resident/Property Owner
Hinkley, CA

Dear Resident/Property Owner:

We are writing to provide you with the results of the tests that the Lahontan Regional Water Quality Control Board recently performed on water from your private well (located at ADDRESS). Your private well water was tested because it is located near the area of the groundwater that has been contaminated with chromium 6 (hexavalent chromium) by the Pacific Gas and Electric Company. We (the California Department of Health Services Environmental Health Investigations Branch) recommended that the Lahontan Regional Water Quality Control Board measure the levels of total chromium and chromium 6 in private wells located near the chromium 6 groundwater contamination.

The Lahontan Regional Water Quality Control Board collected water samples from your well on August 1 and August 8, 2001. The Lahontan Regional Water Quality Control Board had E.S. Babcock & Sons laboratory measure the levels of total chromium and chromium 6 in your well water. In order to learn more about the characteristics and quality of the groundwater, they also had NEL laboratories analyze your water for metals, minerals and other inorganic water do not pose a risk to your health. However, the amount of nitrate, lead, thallium, chloride, iron, manganese, specific conductance, sulfate, and total dissolved solids in your water do exceed public drinking water standards and therefore may affect the safety or the quality (taste, odor, appearance) of your well water.

compounds. At high levels, these compounds can make water either unsafe or unpleasant (bad taste, odor or appearance) to drink. Copies of the laboratory reports for both water samples are included with this letter.

We reviewed the results of the tests that were performed on water from your private well. We also compared the levels of compounds in your water to the levels that are allowed in public drinking water systems. (The state of California regulates public drinking water systems in order to ensure the safety and the quality of public water supplies.)

As we will explain in more detail in the remainder of this letter, the levels of total chromium and chromium 6 in your drinking

Results for Total Chromium and Chromium 6

The California drinking water standard for total chromium was created in order to ensure that public water supplies are safe to drink. The drinking water standard for total chromium is 50 micrograms per liter (µg/L). There is no specific drinking water standard for chromium 6.

Total chromium is made up of chromium 3 (trivalent chromium) and chromium 6. The E.S. Babcock & Sons laboratory measured the levels of both total chromium and chromium 6 in the water sampled on August 8. The test results show that your private well water contains 6 µg/L total chromium and non-detectable levels of chromium 6 (less than 1 µg/L chromium 6).

The amount of total chromium in your private well water is below the drinking water standard for total chromium and therefore does not pose a risk to your health.

We have included a fact sheet that provides more information on chromium in drinking water and on the chromium drinking water standard.

Results for Nitrate

The California drinking water standard for nitrate was created to ensure that public water supplies are safe to drink. The drinking water standard for nitrate is 10 milligrams per liter as nitrogen (mg/L-N).

The tests measured 19 mg/L-N nitrate in the water sampled on August 1 and 24 mg/L-N in the water sampled on August 8. These levels are greater than the California drinking water standard of 10 mg/L-N. The source of the nitrate contamination of your well water is unknown; however, nitrate is commonly found in water supplies, especially in agricultural areas.

Pregnant women and young infants who drink water contaminated with high levels of nitrate are the most at risk of developing serious health problems. However, these health problems will stop once you are no longer exposed to nitrate. If you are pregnant or have a young infant (under six months old), we recommend that you use different water (for example, municipal or bottled water) for drinking, cooking, and making infant formula.

We have included a brochure that provides more information on nitrate. The brochure is titled "Health Concerns Related to Nitrate and Nitrite in Private Well Water."

Results for Lead

The California drinking water standard for lead was created to ensure that public water supplies are safe to drink. The drinking water standard for lead is 0.015 milligrams per liter (mg/L).

The tests measured 0.099 mg/L lead in the water sampled on August 1 and 0.086 mg/L lead in the water sampled on August 8. These levels are higher than the California drinking water standard of 0.015 mg/L.

Children under six years old are at the highest risk for lead poisoning. Lead poisoning can harm the brain, nerves and kidneys of a young child and make it very hard for a child to learn, pay attention, and behave. Most children with lead poisoning do not look or act sick.

There are many ways that children may be exposed to lead, including air, water, dust, soil and older paints that contain lead. We have included two brochures that provide more information on childhood lead poisoning and the ways that children may be exposed to lead.

A child who drinks water from your well and who is also exposed to lead from other common sources may be exposed to greater amounts of lead than is recommended. If you have a young child who drinks water from your well, or if you have other sources of lead exposure in your home (for example, paint manufactured before 1978), we recommend that you use different water (municipal or bottled). We also recommend that the child have a blood lead test. The blood lead test is the only way to know if your child has lead poisoning. Your doctor or clinic can give your child a blood lead test. You may also call the San Bernardino County Childhood Lead Poisoning Prevention Program at (909) 387-6305 for further information on lead poisoning and the blood lead test.

The source of the lead contamination is currently unknown. Because water was taken from your well and not from inside your house, we do know that the source of the lead contamination is not your plumbing. The lead in your water could be coming from a material that was used to construct your well or from an outside source that has contaminated the groundwater in your area. We recommend that you ask your well constructor if lead solder was used to construct your well. This information should be recorded in the drill records for your well.

Results for Thallium

The California drinking water standard for thallium was created to ensure that public water supplies are safe to drink. The drinking water standard for thallium is 0.002 mg/L.

The tests did not detect thallium in the water sampled on August 1 (thus, the levels were less than 0.1 mg/L), but did measure 0.19 mg/L thallium in the water sampled on August 8. This level is greater than the California drinking water standard of 0.002 mg/L.

People who consume high amounts of thallium for a short period of time can experience problems with their digestion and nervous systems. Exposure to high levels of thallium over a lifetime can cause hair loss, changes in blood chemistry, or damage to the liver, kidney, and digestive tract.

Because the level of thallium in your well water is above the drinking water standard, we recommend that you use water from a different source (bottled or municipal) for drinking, cooking, and watering your vegetable, fruit garden. It may also be advisable to not give your well water to your animals. We also recommend that you test your well water for thallium again in order to confirm and better understand the amount of thallium in your water.

The source of the thallium contamination in your well water is currently unknown. Thallium is a metal that is found in natural deposits in soil and rock. Leaching from ore processing operations is the major source of thallium contamination in water.

Results for Chloride, Iron, Manganese, Specific Conductance, Sulfate, and Total Dissolved Solids

The drinking water standards for chloride, iron, manganese, specific conductance, sulfate, and total dissolved solids were created in order to protect the quality (taste, odor, appearance) of public water supplies. The standard for chloride is 250 mg/L, for iron is 0.3 mg/L, for manganese is 0.05 mg/L, for specific conductance is 900 micromhos (µS/cm), for sulfate is 250 mg/L and for total dissolved solids is 500 mg/L.

The levels of chloride, iron, manganese, specific conductance, sulfate and total dissolved solids measured in the two water samples from your well are listed in the chart below:

  Level Measured on August 1 Higher than drinking water standard? Level Measured on August 8 Higher than drinking water standard?
chloride 1,100 mg/L Yes 1,100 mg/L Yes
iron 0.68 mg/L Yes 1.1 mg/L Yes
manganese 0.059 mg/L Yes 0.021 mg/L No
specific conductance 5,240 µS/cm Yes 5,090 µS/cm Yes
sulfate 1,000 mg/L Yes 1,100 mg/L Yes
total dissolved 3,390 mg/L Yes 3,800 mg/L Yes

Except for the level of manganese measured in water sampled on August 8th, all of the levels of chloride, iron, manganese, specific conductance, sulfate and total dissolved solids measured in your water were higher than the California drinking water standards. High levels of chloride, iron, manganese, specific conductance, sulfate, and total dissolved solids may affect the taste, odor or appearance of your well water. These compounds do not put your health at risk.

Follow-up Testing

Two water tests do not provide enough information to fully understand the safety and quality of your water. For this reason, the Lahontan Regional Water Quality Control Board would like to take another sample of your well water in the near future. They will retest the water for nitrate, lead, thallium, chloride, iron, manganese, specific conductance, sulfate, and total dissolved solids. Lahontan Regional Water Quality Control Board will provide you with the results of these tests.

Recommendations for Private Well Owners

Many chemicals, metals, minerals and bacteria may be present in private wells and may threaten the safety and quality of your drinking water. These compounds can come from both natural sources and human activity. Private drinking water wells are not regulated or tested by the state, so people with private wells are responsible for making sure that their own drinking water is safe.

We have recommended that you do not use your well water for drinking and cooking. Should you switch to a different or a new well, we encourage you to routinely test that well to ensure the safety of your drinking water. Since bacteria are the most common problem in private wells, we would suggest that you also have the water tested for coliform.

Lastly, California-certified water filters and treatment systems that you can purchase in stores are not intended to treat water with levels of contaminants that are above the heath-based drinking water standard. Therefore, we do not recommend that you rely upon these filters and treatment systems to reduce the levels of nitrate, lead, and mercury measured in your well water.

If you have any questions about the information we have provided, please do not hesitate to call Tracy Barreau at (510) 622-4489 or Jackie Schwartz at (510) 622-4487.

Sincerely,


Jackie Schwartz, MPH
Environmental Health Scientist
Environmental Health Investigations Branch

Marilyn Underwood, Ph.D.
Staff Toxicologist
Environmental Health Investigations Branch

Enclosures

cc:

Harold Singer, Executive Officer
Lahontan Regional Water Quality Control Board
2501 Lake Tahoe Boulevard
South Lake Tahoe, CA 96150

Mike Plaziak, Acting Mojave Unit Chief
Lahontan Regional Water Quality Control Board
15428 Civic Drive, Suite 100
Victorville, CA 92392

Joe Koutsky, AWRCE
Lahontan Regional Water Quality Control Board
15428 Civic Drive, Suite 100
Victorville, CA 92392

William Vance, Assistant Secretary of Air and Water Programs
California Environmental Protection Agency
1001 "I" Street, 25th Floor
Sacramento, CA 95814

Lynn Baker, Staff Air Pollution Specialist
California Air Resources Board
1001 "I" Street, 6th Floor
Sacramento, CA 95814

PROPERTY OWNER


APPENDIX B: LETTER TO HINKLEY RESIDENT/PROPERTY OWNER

To: Hinkley Resident
Re: Results of Private Well Testing
From: The California Department of Health Services
Date: September 14, 2001


DEPARTMENT OF HEALTH SERVICES
1515 CLAY STREET, SUITE 1700
OAKLAND, CA 94612
(510) 622-4500


September 14, 2001

Community Member
Hinkley, CA

Dear Community Member:

We are writing to provide you with the results of the tests that the Lahontan Regional Water Quality Control Board recently performed on water from your private well (located at ADDRESS). Your private well water was tested because it is located near the area of the groundwater that has been contaminated with chromium 6 (hexavalent chromium) by the Pacific Gas and Electric Company. We (the California Department of Health Services Environmental Health Investigations Branch) recommended that the Lahontan Regional Water Quality Control Board measure the levels of total chromium and chromium 6 in private wells located near the chromium 6 groundwater contamination.

The Lahontan Regional Water Quality Control Board had E.S. Babcock & Sons laboratory measure the levels of total chromium and chromium 6 in your private drinking well water. In order to learn more about the characteristics and quality of the groundwater, they also had NEL laboratories analyze your water for metals, minerals and other inorganic compounds. At high levels, these compounds can make water either unsafe or unpleasant (bad taste, odor or appearance) to drink. Copies of the laboratory reports are included with this letter.

We reviewed the results of the tests that were performed on water from your private well. We also compared the levels of compounds in your water to the levels that are allowed in public drinking water systems. (The state of California regulates public drinking water systems in order to ensure the safety and the quality of public water supplies.)

As we will explain in more detail in the remainder of this letter, the levels of total chromium and chromium 6 in your drinking water do not pose a risk to your health. However, the levels of nitrate, lead, mercury, chloride, specific conductance, sulfate, and total dissolved solids in your water do exceed public drinking water standards and therefore may affect the safety or the quality (taste, odor, appearance) of your well water.

Results for Total Chromium and Chromium 6

The California drinking water standard for total chromium was created in order to ensure that public water supplies are safe to drink. The drinking water standard for total chromium is 50 micrograms per liter (µg/L). There is no specific drinking water standard for chromium 6.

Total chromium is made up of chromium 3 (trivalent chromium) and chromium 6. The Lahontan Regional Water Quality Control Board measured the levels of total chromium and chromium 6 in your water. The test results show that your private well water contains 4 µg/L ppb total chromium and 0.68 µg/L chromium 6.

The amount of total chromium in your private well water is below the drinking water standard for total chromium and therefore does not pose a risk to your health.

We have included a fact sheet that provides more information on chromium in drinking water and on the chromium drinking water standard.

Results for Nitrate

The California drinking water standard for nitrate was created to ensure that public water supplies are safe to drink. The drinking water standard for nitrate is 10 milligrams per liter as nitrogen (mg/L-N).

The test results show that the amount of nitrate in your private well water is 12 mg/L-N. This level is greater than the California drinking water standard of 10 mg/L-N. The source of the nitrate contamination of your well water is unknown; however, nitrate is commonly found in water supplies, especially in agricultural areas.

Pregnant women and young infants who drink water contaminated with high levels of nitrate are the most at risk of developing serious health problems. However, these health problems will stop once you are no longer exposed to nitrate. If you are pregnant or have a young infant (under six months old), we recommend that you use different water (for example, municipal or bottled water) for drinking, cooking, and making infant formula.

We have included a brochure that provides more information on nitrate. The brochure is titled "Health Concerns Related to Nitrate and Nitrite in Private Well Water."

Results for Lead

The California drinking water standard for lead was created to ensure that public water supplies are safe to drink. The drinking water standard for lead is 0.015 milligrams per liter (mg/L).

The test results show that the amount of lead in your private well water is 0.10 mg/L. The amount of lead in your water is higher than the California drinking water standard of 0.015 mg/L.

Children under six years old are at the highest risk for lead poisoning. Lead poisoning can harm the brain, nerves and kidneys of a young child and make it very hard for a child to learn, pay attention, and behave. Most children with lead poisoning do not look or act sick.

There are many ways that children may be exposed to lead, including air, water, dust, soil and older paints that contain lead. We have included two brochures that provide more information on childhood lead poisoning and the ways that children may be exposed to lead.

A child who drinks water from your well and who is also exposed to lead from other common sources may be exposed to greater amounts of lead than is recommended. If you have a young child who drinks water from your well, or if you have other sources of lead exposure in your home (for example, paint manufactured before 1978), we recommend that you use different water (municipal or bottled). We also recommend that the child have a blood lead test. The blood lead test is the only way to know if your child has lead poisoning. Your doctor or clinic can give your child a blood lead test. You may also call the San Bernardino County Childhood Lead Poisoning Prevention Program at (909) 387-6305 for further information on lead poisoning and the blood lead test.

The source of the lead contamination is currently unknown. Because water was taken from your well and not from inside your house, we do know that the source of the lead contamination is not your plumbing. The lead in your water could be coming from a material that was used to construct your well or from an outside source that has contaminated the groundwater in your area. We recommend that you ask your well constructor if lead solder was used to construct your well. This information should be recorded in the drill records for your well.

Results for Chloride, Specific Conductance, Sulfate, and Total Dissolved Solids

The drinking water standards for chloride, specific conductance, sulfate, and total dissolved solids were created in order to protect the quality (taste, odor, appearance) of public water supplies. The standard for chloride is 250 mg/L, for specific conductance is 900 micromhos (µS/cm), for sulfate is 250 mg/L and for total dissolved solids is 500 mg/L.

The test results show that your private well water has 870 mg/L chloride, 4310 µ/cm specific conductance, 790 mg/L sulfate, and 2940 mg/L total dissolved solids. These levels are higher than the California drinking water standards. High levels of chloride, specific conductance, sulfate and total dissolved solids may affect the taste, odor or appearance of your well water. However, these compounds do not put your health at risk.

Follow-up Testing

One water test does not provide enough information to fully understand the safety and quality of your water. For this reason, the Lahontan Regional Water Quality Control Board would like to take another sample of your well water in the near future. They will retest the water for nitrate, lead, mercury, chloride, specific conductance, sulfate, and total dissolve solids. Lahontan Regional Water Quality Control Board will provide you with the results of these tests.

Recommendations for Private Well Owners

Many chemicals, metals, minerals and bacteria may be present in private wells and may threaten the safety and quality of your drinking water. These compounds can come from both natural sources and human activity. Private drinking water wells are not regulated or tested by the state, so people with private wells are responsible for making sure that their own drinking water is safe.

We encourage you to have your well water tested routinely to ensure the safety of your drinking water. Since bacteria are the most common problem in private wells, we would suggest that you have your well tested for coliform on a periodic basis. Lahontan Regional Water Quality Control Board did not perform a bacteria test on your well water.

Lastly, California-certified water filters and treatment systems that you can purchase in stores are not intended to treat water with levels of contaminants that are above the heath-based drinking water standard. Therefore, we do not recommend that you rely upon these filters and treatment systems to reduce the levels of nitrate, lead, and mercury measured in your well water.

If you have any questions about the information we have provided, please do not hesitate to call Tracy Barreau at (510) 622-4489 or Jackie Schwartz at (510) 622-4487.

Sincerely,


Jackie Schwartz, MPH
Environmental Health Scientist
Environmental Health Investigations Branch

Marilyn Underwood, Ph.D.
Staff Toxicologist
Environmental Health Investigations Branch

Enclosures

cc:

Harold Singer, Executive Officer
Lahontan Regional Water Quality Control Board
2501 Lake Tahoe Boulevard
South Lake Tahoe, CA 96150

Mike Plaziak, Acting Mojave Unit Chief
Lahontan Regional Water Quality Control Board
15428 Civic Drive, Suite 100
Victorville, CA 92392

Joe Koutsky, AWRCE
Lahontan Regional Water Quality Control Board
15428 Civic Drive, Suite 100
Victorville, CA 92392

William Vance, Assistant Secretary of Air and Water Programs
California Environmental Protection Agency
1001 "I" Street, 25th Floor
Sacramento, CA 95814

Lynn Baker, Staff Air Pollution Specialist
California Air Resources Board
1001 "I" Street, 6th Floor
Sacramento, CA 95814

PROPERTY OWNER


APPENDIX C: LETTER TO HINKLEY RESIDENT

To: Hinkley Resident
Re: Results of Private Well Testing
From: The California Department of Health Services
Date: September 14, 2001


DEPARTMENT OF HEALTH SERVICES
1515 CLAY STREET, SUITE 1700
OAKLAND, CA 94612
(510) 622-4500


September 14, 2001

Resident/Property Owner
Hinkley, CA

Dear Resident/Property Owner:

We are writing to provide you with the results of the tests that the Lahontan Regional Water Quality Control Board recently performed on water from your private well (located at ADDRESS). Your private well water was tested because it is located near the area of the groundwater that has been contaminated with chromium 6 (hexavalent chromium) by the Pacific Gas and Electric Company. We (the California Department of Health Services Environmental Health Investigations Branch) recommended that the Lahontan Regional Water Quality Control Board measure the levels of total chromium and chromium 6 in private wells located near the chromium 6 groundwater contamination.

The Lahontan Regional Water Quality Control Board had E.S. Babcock & Sons laboratory measure the levels of total chromium and chromium 6 in your private drinking well water. In order to learn more about the characteristics and quality of the groundwater, they also had NEL laboratories analyze your water for metals, minerals and other inorganic compounds. At high levels, these compounds can make water either unsafe or unpleasant (bad taste, odor or appearance) to drink. Copies of the laboratory reports are included with this letter.

We reviewed the results of the tests that were performed on water from your private well. We also compared the levels of compounds in your water to the levels that are allowed in public drinking water systems. (The state of California regulates public drinking water systems in order to ensure the safety and the quality of public water supplies.)

As we will explain in more detail in the remainder of this letter, the levels of total chromium and chromium 6 in your drinking water do not pose a risk to your health. However, the levels of lead, chloride, specific conductance, sulfate, and total dissolved solids in your water do exceed public drinking water standards and therefore may affect the safety or the quality (taste, odor, appearance) of your well water.

Results for Total Chromium and Chromium 6

The California drinking water standard for total chromium was created in order to ensure that public water supplies are safe to drink. The drinking water standard for total chromium is 50 micrograms per liter (µg/L). There is no specific drinking water standard for chromium 6.

Total chromium is made up of chromium 3 (trivalent chromium) and chromium 6. The Lahontan Regional Water Quality Control Board measured the levels of total chromium and chromium 6 in your water. The test results show that your private well water contains 6 µg/L ppb total chromium and 0.63 µg/L chromium 6.

The amount of total chromium in your private well water is below the drinking water standard for total chromium and therefore does not pose a risk to your health.

We have included a fact sheet that provides more information on chromium in drinking water and on the chromium drinking water standard.

Results for Lead

The California drinking water standard for lead was created to ensure that public water supplies are safe to drink. The drinking water standard for lead is 0.015 milligrams per liter (mg/L).

The test results show that the concentration of lead in your private well water is 0.079 mg/L. This amount is higher than the California drinking water standard of 0.015 mg/L.

Children under six years old are at the highest risk for lead poisoning. Lead poisoning can harm the brain, nerves and kidneys of a young child and make it very hard for a child to learn, pay attention, and behave. Most children with lead poisoning do not look or act sick.

There are many ways that children may be exposed to lead, including air, water, dust, soil and older paints that contain lead. We have included two brochures that provide more information on childhood lead poisoning and the ways that children may be exposed to lead.

A child who drinks water from your well and who is also exposed to lead from other common sources may be exposed to greater amounts of lead than is recommended. If you have a young child who drinks water from your well, or if you have other sources of lead exposure in your home (for example, paint manufactured before 1978), we recommend that you use different water (municipal or bottled). We also recommend that the child have a blood lead test. The blood lead test is the only way to know if your child has lead poisoning. Your doctor or clinic can give your child a blood lead test. You may also call the San Bernardino County Childhood Lead Poisoning Prevention Program at (909) 387-6305 for further information on lead poisoning and the blood lead test.

The source of the lead contamination is currently unknown. Because water was taken from your well and not from inside your house, we do know that the source of the lead contamination is not your plumbing. The lead in your water could be coming from a material that was used to construct your well or from an outside source that has contaminated the groundwater in your area. We recommend that you ask your well constructor if lead solder was used to construct your well. This information should be recorded in the drill records for your well.

Results for Chloride, Specific Conductance, Sulfate, and Total Dissolved Solids

The drinking water standards for chloride, specific conductance, sulfate, and total dissolved solids were created in order to protect the quality (taste, odor, appearance) of public water supplies. The standard for chloride is 250 mg/L, for specific conductance is 900 micromhos (µS/cm), for sulfate is 250 mg/L and for total dissolved solids is 500 mg/L.

The test results show that your private well water has 660 mg/L chloride, 3600 µS/cm specific conductance, 580 mg/L sulfate, and 2340 mg/L total dissolved solids. These levels are higher than the California drinking water standards. High levels of chloride, specific conductance, sulfate, and total dissolved solids may affect the taste, odor or appearance of your well water. These compounds do not put your health at risk.

Follow-up Testing

One water test does not provide enough information to fully understand the safety and quality of your water. For this reason, the Lahontan Regional Water Quality Control Board would like to take another sample of your well water in the near future. They will retest the water for lead, thallium, chloride, specific conductance, sulfate, and total dissolved solids. Lahontan Regional Water Quality Control Board will provide you with the results of these tests.

Recommendations for Private Well Owners

Many chemicals, metals, minerals and bacteria may be present in private wells and may threaten the safety and quality of your drinking water. These compounds can come from both natural sources and human activity. Private drinking water wells are not regulated or tested by the state, so people with private wells are responsible for making sure that their own drinking water is safe.

We encourage you to have your well water tested routinely to ensure the safety of your drinking water. Since bacteria are the most common problem in private wells, we would suggest that you have your well tested for coliform on a periodic basis. The Lahontan Regional Water Quality Control Board did not perform a bacteria test on your well water.

Lastly, California-certified water filters and treatment systems that you can purchase in stores are not intended to treat water with levels of contaminants that are above the heath-based drinking water standard. Therefore, we do not recommend that you rely upon these filters and treatment systems to reduce the levels of nitrate, lead, and mercury measured in your well water.

If you have any questions about the information we have provided, please do not hesitate to call Tracy Barreau at (510) 622-4489 or Jackie Schwartz at (510) 622-4487.

Sincerely,


Jackie Schwartz, MPH
Environmental Health Scientist
Environmental Health Investigations Branch

Marilyn Underwood, Ph.D.
Staff Toxicologist
Environmental Health Investigations Branch

Enclosures

cc:

Harold Singer, Executive Officer
Lahontan Regional Water Quality Control Board
2501 Lake Tahoe Boulevard
South Lake Tahoe, CA 96150

Mike Plaziak, Acting Mojave Unit Chief
Lahontan Regional Water Quality Control Board
15428 Civic Drive, Suite 100
Victorville, CA 92392

Joe Koutsky, AWRCE
Lahontan Regional Water Quality Control Board
15428 Civic Drive, Suite 100
Victorville, CA 92392

William Vance, Assistant Secretary of Air and Water Programs
California Environmental Protection Agency
1001 "I" Street, 25th Floor
Sacramento, CA 95814

Lynn Baker, Staff Air Pollution Specialist
California Air Resources Board
1001 "I" Street, 6th Floor
Sacramento, CA 95814

PROPERTY OWNER


APPENDIX D: LETTER TO HINKLEY RESIDENTS

To: Hinkley Resident
Re: Follow-Up Letter Regarding Private Well Sampling
From: The California Department of Health Services
Date: October 1, 2001


DEPARTMENT OF HEALTH SERVICES
1515 CLAY STREET, SUITE 1700
OAKLAND, CA 94612
(510) 622-4500


October 1, 2001

Resident/Property Owner
Hinkley, CA

Dear Resident/Property Owner:

We are writing to follow up on our phone conversations during the past few days about your private well water. During these conversations, we discussed: the water test you did in 1994; the safety and quality of water from three wells on your property; how the water might affect your animals; where the contamination came from; water treatment options; regular water testing; and some recommended changes to how you use your well water. This letter will summarize the information and recommendations that Jackie Schwartz gave you on the phone.

1994 Well Water Test

When we receive a copy of the results of the water test in 1994, we will review the test results and methods and will report back to you on how the 1994 test fits with the recent test. If you have not already done so, please send a copy of the lab report to:

Jackie Schwartz
CDHS-Environmental Health Investigations Branch
1515 Clay Street, 17th floor
Oakland, CA 94612

We recommend that you also send a copy of the test results to the Lahontan Regional Water Quality Control Board. This information will be useful to their work to protect the quality of underground water in your area. Their address is:

Joe Koutsky and Jehiel Cass
Lahontan Regional Water Quality Control Board
15428 Civic Dr., Suite 100
Victorville, CA 92392

The Safety and Quality of Your Water

As we discussed on the phone, you have three wells on your property, and all three wells were tested by the Lahontan Regional Water Quality Control Board in August. You use the well located at (ADDRESS OF WELL #1) for your fields and animals. The well located at (ADDRESS OF WELL #2) is the water supply for your house.

And the well at (ADDRESS OF WELL #3) supplies your daughter's home. There are no infants, children or pregnant women who consume the water from these wells.

Lead: All three wells had levels of lead that are above the California drinking water standard for public drinking water systems. As we wrote to you in our previous letter, children under 6 years of age are at higher risk for lead poisoning than adults. Although the levels of lead in your water are less likely to result in lead poisoning for adults, we recommend that you do not drink or cook with water from these wells. Instead, use bottled or municipal water, or install a water treatment system on your well that is certified to reduce the level of lead in your water to below the drinking water standard.

Nitrate: Two of the three wells on your property had levels of nitrate that are above the drinking water standard. As we previously explained, pregnant women and formula-fed infants under the age of 6 months are the most sensitive to nitrate. The risk of health conditions from nitrate in water is lower for adults. Even so, we recommend that you do not drink or cook with water from these two wells. Instead, use bottled or municipal water, or install a water treatment system on your well that is certified to reduce the level of nitrate in your water to below the drinking water standard.

Thallium. The water tests found that one of the three wells on your property had levels of thallium higher than the drinking water standard. This well (WELL #1) was tested twice and thallium was detected in one of these tests. The Lahontan Regional Water Quality Control Board is going to test your well again for thallium. The results of this test will provide more information about whether the thallium contamination is permanent or temporary. Until more is known about the thallium contamination, we recommend that you do not drink or cook with water from your field well. Instead, use bottled or municipal water, or install a water treatment system on your well that is certified to reduce the level of thallium in your water to below the drinking water standard. You may use this well to water your trees and any plant that you do not use for food.

How the Water Might Affect your Animals

We contacted the California Animal Health and Food and Safety Laboratory for information on the possible risk to your animals (horses, cows, dogs and cats). They provided information on the maximum recommended levels in drinking water for livestock. These levels are listed below:

compound maximum recommended drinking water level for livestock

lead 0.05 to 0.1 milligrams per liter (mg/L)
nitrate 23 mg/L
thallium 0.05 mg/L (estimated)

Based on this information, we can conclude that:

  • The level of lead measured in all three of your wells is within the range of maximum recommended levels for livestock. Levels of lead in your water are not expected to cause health problems in livestock.


  • The level of nitrate measured in your field well (ADDRESS OF WELL #1) on one of the two times it was tested is higher than the maximum recommended level for livestock. However, as we discussed on the phone, the maximum level for nitrate is designed to protect ruminants (cows, sheep, goats). The levels of nitrate measured in water from your three wells (6.9 - 24 mg/L) should not pose a health threat to animals such as horses, dogs and cats.


  • The maximum recommended level of thallium for livestock is an estimated level which was based on the maximum recommended level for food. The level of thallium measured during one out of two tests of your field well water is higher than the estimated maximum recommended level for livestock. As we explained earlier in this letter, there is some uncertainty about the level of thallium in the water from this well because the second test did not detect thallium. Until more information is available on the level of thallium in the water from your field well (ADDRESS OF WELL #1), it is recommended that you not feed this water to your animals.

Where the Contamination Came From

As we discussed on the phone, the source of the lead, nitrate, and thallium contamination in your wells is not known. You mentioned on the phone that you live close to a dairy and that this dairy has increased the number of cattle during the past few years. Nitrate is a common water contaminant in agricultural and livestock areas. The possible sources of the lead and thallium contamination are more difficult to identify.

The Lahontan Regional Water Quality Control Board is one of the California government agencies responsible for water quality in the state. It is part of their responsibility to regulate waste discharges, to take enforcement actions against violators and to monitor water quality. We recommend that you contact the Lahontan Regional Water Quality Control Board with your questions about the source of the contamination in your wells, as well as your concerns about the dairy and about the nitrate and lead levels in your water.

Water Treatment Options

No water filters or treatment systems that you can buy at a store are certified to reduce the levels of nitrate, lead and thallium to below the drinking water standard. However, there are some professionally-installed water treatment systems that can substantially reduce the level of contamination.

We contacted the Drinking Water Program of the California Department of Health Services to learn which professional water treatment systems are certified to reduce the levels of lead, nitrate and thallium in the water in your three wells. There were not able to recommend any specific water treatment systems. However, they did recommend that you contact a water softener or treatment company in your area and talk to them about treatment systems that would reduce your levels of contaminants in your well water. I obtained the following list of water treatment companies in the Hinkley area from the Yellow Pages:

Superior Softwater, in Barstow (760) 256-3621
Culligan Water Conditioning, in Barstow (760) 242-8884
Servisoft Water Conditioning, in Barstow (760) 256-3827
AAA Purification, in Apple Valley (760) 242-9714
Rainsoft Water Treatment Systems, in Victorville (760) 951-7605

Regular Water Testing

Bacteria contamination is common in well water. The Lahontan Regional Water Quality Control Board did not test your water for bacteria. Therefore, we recommend that you have your wells tested for bacteria. For information on professional water testing services, contact Scott Rose at the Safe Drinking Water Program of the San Bernardino County Department of Public Health. His phone number is (909) 387-4666.

We also recommend that you have your well water tested on a regular basis (at least once a year). Testing your water on a regular basis will help you to understand if the contamination in your well water is changing. It is also important information should you decide to install a water treatment system. Scott Rose of the Safe Drinking Water Program (phone: (909) 387-4666) can give you information on water testing services.

Recommended Changes to How You Use Your Well Water.

During our conversations, you explained that you use the field well (ADDRESS OF WELL #1) to water your fields and animals. You also mentioned that you could use water from your home well (ADDRESS OF WELL #2) to feed your animals. Because one of the two tests measured high levels of thallium in water from your field well, we recommend that you use water from your home well to feed your animals.

Summary of Recommendations

  • Send a copy of your 1994 well test to Jackie Schwartz at CDHS and to the Lahontan Regional Water Quality Control Board (see above for addresses).


  • Do not drink or cook with water from your three wells. (The water can be used for all other purposes (laundry, washing, etc.)) If you do not wish to have a water treatment systems installed, bottled water should be used for drinking and cooking.


  • Do not feed your animals water from your field well. (Water from this well can be used to water your trees and any other plants that are not food sources.)


  • Contact Lahontan Regional Water Quality Control Board if you want to:
    • find out when your well will be retested;
    • ask questions about possible sources of contamination; or
    • learn more about their efforts to protect water quality in your area.


  • Should you decide to install a professional water treatment system, contact the companies listed above for further information on cost, installation, etc. Make sure that the system you install is certified to remove nitrate, lead and thallium from water with your levels of contamination.


  • Have the water from your wells tested for bacteria, since this test was not performed by the Lahontan Regional Water Quality Control Board.


  • Test your well water at least once a year. Contact Scott Rose, San Bernardino County Safe Drinking Water Program (phone: (909) 387-4666) for information on water testing.

If you have any questions or concerns, please contact Jackie Schwartz at (510) 622-4487 or Tracy Barreau at (510) 622-4489.

Sincerely,

Marilyn Underwood, Ph.D.
Staff Toxicologist
Environmental Health Investigations Branch

Jackie Schwartz, MPH
Research Scientist
Environmental Health Investigations Branch

cc:

Jehiel Cass
Lahontan Regional Water Quality Control Board
15428 Civic Dr., Suite 100
Victorville, CA 92392


APPENDIX E: FACT SHEET ON CHROMIUM IN DRINKING WATER


Click here to see this Fact Sheet online


APPENDIX F: FACT SHEET: HEALTH CONCERNS RELATED TO NITRATE AND NITRITE IN PRIVATE WELL WATER


Click here to view Appendix F in PDF Format (232KB, PDF)


APPENDIX G: INFORMATION BROCHURE: LEAD POISONING AND YOUR CHILDREN


Click here to view Appendix G in PDF Format (215KB, PDF)


APPENDIX H: INFORMATION BROCHURE: LEAD POISONING: ARE YOUR CHILDREN IN DANGER?


Click here to view Appendix H in PDF Format (2107KB, PDF)

Table of Contents

  
 
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