The contaminated water crisis in Flint, Michigan became a beacon of failure in governmental oversight and put thousands of lives – dogs and cats included – at risk for lead toxicity. The Environmental Protection Agency (EPA) now deems the water to be safe there, but the quite reasonable mistrust lingers amongst residents.
The general problem of lead poisoning, though, has been increasing and is not limited to Flint. Jackson, Mississippi and Chicago both come to mind…and that’s just regarding contaminated water.
In October 2023, applesauce products were recalled due to elevated lead levels linked to the cinnamon from an Ecuadoran processing company.
In this article, we plan to examine: the history of lead regulations; testing; prevention tips; as well as the role and presence of lead toxicity dogs and cats.
History
Since 1971, the United States Government and individual states have been passing sweeping legislation to slowly phase out, limit, or decrease thresholds of lead in various products such as paint, dish ware, food cans, plumbing and gasoline.
The biggest threats, though, are pre-existing to these regulations. Older construction may still have plumbing that has the potential to contribute lead to drinking water. Homes and buildings built before 1978 may have chipping, deteriorating or underlying lead-based paint. Ceramics purchased prior to the updated regulations or antiques may still be in use.
The problem in Flint was a bit different and more on an epidemic scale. The water supply of Flint bombarded the aging lead pipe infrastructure with a highly corrosive water that provoked the leaching of lead at an alarming rate. Several communities treat water or source it from less corrosive waterways to work around this problem.
In essence, we can probably never eliminate lead entirely, but with proper attention to the issues can mitigate the associated risks.
Testing for Lead
The type of testing depends on the item as food, water, pipes, paint, ceramics, children’s toys or other consumer product goods like pet toys. Since there are so many categories, we will focus on paint and consumer product goods like ceramic plates.
The Food and Drug Administration (FDA) does keep a red list of flagged imports, and steers consumers away from dishware manufactured in Mexico and China.
The FDA mentions DIY kits:
“Consumers can buy lead-testing kits in hardware stores or online. The kits contain swabs with instructions on proper use of the swabs and reading of the results. In most cases, the consumer will rub the swab on the food-contacting surface of the pottery. In most kits, if the pottery contains lead that leaches onto the swab, it will change colors. If a consumer performs a test and finds the pottery contains leachable lead, the FDA strongly advises against using the pottery for cooking, serving, or storing food or drinks.”
The Centers for Disease Control and Prevention (CDC) is a bit more cautious, “You can test products for lead by submitting a sample to a certified laboratory. Only a certified laboratory can accurately test products for lead content. Although do-it-yourself kits are available, they do not show how much lead is present. Additionally, their reliability in detecting low lead levels has not been determined.”
The EPA mentions a couple of other products for testing lead in house paint that meet certain criterion.
The Safe Lead Mama, Tamara Rubin – who has been spotlighted in Consumer Reports – does not recommend any kits for consumer product goods such as ceramics. She does recommend one or two that test for lead presence in house paint.
She instead recommends testing consumer product goods with an X–Ray Fluorescence spectrometry analyzer. According to her, “XRF testing must be done by an individual trained and certified in the proper use of this equipment.”
We randomly selected a dish manufactured in Germany in the 2000’s she tested in 2018.
She wrote:
“Modern newly manufactured dishware today is not regulated for total lead and cadmium content as detectable with an XRF instrument. Instead modern dishware is usually only regulated to meet leach testing standards at the time of manufacture (depending on the country of origin.)
My concern is for what happens to a highly leaded piece as it deteriorates over time, especially pieces like this that are very high lead and cadmium, but also considered heirloom quality and may be handed down from generation to generation.
The only standard that one can compare these XRF test results to (comparing apples to apples) is the regulatory standard for lead in items specifically designed and marketed as intended for use by children. The allowable limit for lead [as detectable with an XRF] in an item intended for use by children (including toys and dishware made expressly for use by children) is 90 parts per million (ppm) lead in the glaze or coating or 100 ppm lead in the substrate (the clay under the glaze.)
While this bowl has likely been leach tested and is considered safe for use by adults, if this bowl were intended for use by children it would be a violation of the Consumer Product Safety Improvement Act (CPSIA) of 2008.
Many European regulatory standards for the presence of toxicants are much stricter than U.S. standards – so it is very interesting that this bowl was made in Germany yet still tested positive for a very high level of cadmium. Cadmium is often found in glazes/paints/coatings and substrates that are red, yellow, or orange.”
Summary
From what we gathered, the XRF machine tests for the presence of lead. The FDA is concerned with leachable lead, which is a different test. However, Rubin’s point is that products for children (including dishware) cannot have more than 90 ppm in paint or any similar surface coatings according to the U.S. Consumer Product Safety Commission and the same should be applicable to all products.
Have you noticed that we have mentioned four governmental agencies overseeing various products depending on the function of the products? We think there should be a task force that brings these agencies together similar to the Federal Task Force on Combating Antibiotic-Resistant Bacteria.
Prevention Tips for Dogs and Cats
While lead has been found in some stainless steel, stainless steel is typically safer and lead free depending on the product. Therefore, dogs and cats should drink out of a stainless steel bowl for several reasons. For instance, they are generally very durable and scratch resistant, which helps minimize food particles getting into the crevices.
Cats (and dogs) can develop feline acne or contact hypersensitivity, too, from other types of bowls.
You should make sure you are purchasing the stainless steel from a locally owned and operated pet supply store or kitchen supply store that may have the right size bowl for your pet. Make sure you ask them to ensure that the bowls are sourced reputably and made in a country with strict lead laws.
If you do want to use ceramic or porcelain bowls, apply the same logic as you would to a stainless steel bowl and make sure it is made in the USA. Made in the USA is generally considered safer.
Plastic bowls are best avoided, as they can leach plasticizers and the color can cause contact reactions of the muzzle.
Dogs and cats should always receive filtered water. Independent publications have run tests on the quality of how well water filters actually remove elements found in tap water. These reports are readily available on the web. Please check a few reports before you purchase a new water filtration system.
Finally, if you live in a home built before 1978 and plan to renovate, check the Environmental Protections Agency (EPA) website for excellent tips to minimize the possible amount of lead exposure. If you plan to hire contractors, make sure they plan to follow the EPA’s guidelines.
Acute vs. Chronic Lead Exposure
Acute lead toxicosis in dogs and cats is well documented and researched. Acute poisoning is usually a one-time ingestion of copious amounts of lead found in objects. Puppies are considered at the greatest risk because they often chew incessantly. Additionally, lead crosses the blood-brain barrier more readily in immature animals than in adults.
Chronic lead toxicosis occurs after repeated exposure over time, leading to the accumulation of lead in the body. The onset of chronic toxicosis is generally considered three months.
Lead mimics calcium and zinc so it is absorbed by multiple organs and damages normal cell function. So, a diet deficient in calcium, zinc, iron, or vitamin D can also lead to greater lead absorption.
Lead poisoning can be fatal, but, if found in time, treatment is usually successful.
Acute Lead Toxicosis Symptoms
- Vomiting
- Lethargy
- Anorexia
- Aberrant behavior
- Ataxia
- Tremors
- Seizures
Chronic Lead Toxicosis Symptoms
- Weight loss
- Anorexia
- Lethargy
- Vomiting
- Diarrhea
- Aberrant behavior
- Intermittent seizures
- Anemia
These symptoms sound very similar to other diseases such as distemper or even thyroid disorders – and pet caregivers may be frustrated by that fact. Indeed, chronic lead poisoning is rarely diagnosed in the United States because laws have tried to minimize the amount of lead in the environment. Then again, chronic toxicosis may be more prevalent than assumed because it is not well researched and the thresholds for pets may be set higher than they possibly should be. More on this below.
Environmental Sentinels
Dogs (and sometimes cats) are used as environmental sentinels to determine lead toxicity in a household or community. This means that scientists can project the potential for lead poisoning in a child or adult based on a dog’s blood or hair sample. Fortunately, several studies have surveyed dogs for blood lead levels. Unfortunately, research regarding the chronic, long-term effects and side effects of lead exposure on dogs and cats seems to stop short, once focus is then diverted to humans.
Case in point, Small Animal Clinical Diagnosis by Laboratory Methods states that a blood lead level (BLL) greater than 0.3 ppm is suggestive of excessive exposure and that 0.4 ppm is confirmatory of toxicosis in a pet. This is pretty much standardized across the industry. Bear in mind, CDC has set the blood lead reference value for children at the minimum reportable threshold of a child’s BLL value at .035 ppm. The discrepancy here is concerning – not only for the life of our pets, but also for our children.
Even though these are the “toxic” levels set now for dogs and cats, previous studies have pointed out that more definitive research should be done. Park et al. (2005) evaluated 204 South Korean companion dogs for heavy metal concentrations in the blood. Their research found that as dogs aged, serum metal concentrations of cadmium, chromium, lead, and mercury increased. However, they stated that there were no statistically significant differences in metal concentrations among the group.
Another example is the “Household Pets as Monitors of Lead Exposure to Humans” report, which is a result of a multi-agency collaboration (including the EPA and Illinois Department of Public Health). William Buck and colleagues headed the study in 1991, approximately nine years after a secondary (scrap) lead smelter plant was closed in Granite City, Illinois. It was estimated that up to five square miles of soil surrounding the plant were heavily contaminated with lead. At the time, the CDC set the BLL for children at 0.1 ppm, so the researchers decided to apply the same level to companion pets. Their findings were groundbreaking at the time and still resonate today.
- 29% of dogs and cats surveyed had BLL values greater than or equal to 0.1 ppm. 13% of humans had BLL values greater than or equal to 0.1 ppm.
“The first conclusion that could be drawn from the different proportions of animals and humans with BLL greater than or equal to 0.1 ppm was that household pets tended to be more at risk of having an increased BLL than people, when exposed to a similar environmental lead source. Species-related behavioral patterns could probably explain most of the differences.”
- The correlation between increased BLL and decreased ALAD (delta-aminolevulinic acid dehydratase) was very strong: young pets, 0.95; adult pets, 0.86; and, elderly pets, 0.74.
“The relationship between BLL and ALAD is considered strong for BLL above 0.1 ppm. In our study, the relationship, as measured by the correlation coefficient, remained high even though many BLL values were between 0.05 and 0.1 ppm. Therefore, it appears that ALAD activity remains the most sensitive test for lead exposure, and it also seems that dogs and cats respond in a very similar fashion to lead. The limitations for ALAD activity are that this test must be performed on fresh blood and there is a wide range of variation for normal values. Therefore, it can only be used to study a population and it will not be as useful to assess the lead exposure status of a single animal.”
- Chronic exposure to lead may eventually cause some decrease in hemoglobin concentration (in red blood cells) and an increase in white blood cell counts in humans. This study was the first to indicate the same blood profiles in dogs and cats with BLL values greater than 0.1 ppm. The authors were hesitant to say definitively that lead was the perpetrator because the values were still within normal ranges. Note: Nowadays, veterinarians recognize these irregular blood counts along with abnormal red blood cells as potential indicators of lead poisoning but they could also point to other conditions. So, if your pet visits a veterinarian regularly and blood counts have changed, further testing into potential lead toxicity may be required to rule it out or in as the cause. Treatment should not be given until the diagnosis is confirmed.
Conclusion
Yes; medical advancements have been made over the past 30 years to diagnose lead poisoning more easily in dogs and cats, but this usually has been relegated to acute toxicosis. Symptoms, treatment, and diagnosis of chronic lead toxicosis need to be studied more thoroughly in dogs and cats as incidences will probably continue to increase over the years with the deterioration of aging infrastructure. Plus, we do not know the lifelong side effects of acute or chronic toxicosis at all – even if it is treated. Certainly, it appears that adjustments to the minimum acceptable lead thresholds are needed for dogs and cats.
Additional References
Allen, Robert. “2 Dogs Positive for Lead amid Flint Water Crisis.” Detroit Free Press, 04 Feb. 2016. http://www.freep.com/story/news/local/michigan/flint-water-crisis/2016/02/04/flint-lead-pets-dogs/79704210/.
Backer, Lorraine C., Carol B. Grindem, Wayne T. Corbett, Laura Cullins, and J.L. Hunter. “Pet Dogs as Sentinels for Environmental Contamination.” Science of the Total Environment 274.1-3 (2001): 161-69. https://pubmed.ncbi.nlm.nih.gov/11453293/.
Chen, Xing et al. “Source apportionment based on lead isotope ratios: Could domestic dog’s blood lead be used to identify the level and sources of lead pollution in children?” Chemosphere vol. 308,Pt 1 (2022): 136197. doi:10.1016/j.chemosphere.2022.136197, https://pubmed.ncbi.nlm.nih.gov/36064012/.
Buck, William B., Louise-Marie Cote, and Philippe Berny. “Household Pets as Monitors of Lead Exposure to Humans.” Hazardous Waste Research and Information Center (1994): n. pag. Illinois Sustainable Technology Center. http://www.istc.illinois.edu/info/library_docs/rr/RR-E69.PDF.
Høgåsen, Helga R et al. “Lead intoxication in dogs: risk assessment of feeding dogs trimmings of lead-shot game.” BMC veterinary research vol. 12,1 152. 25 Jul. 2016, doi:10.1186/s12917-016-0771-z, https://pmc.ncbi.nlm.nih.gov/articles/PMC4960786/.
Lee, Justine A., DVM. “Lead Poisoning in Dogs and Cats.” Pet Health Network, 11 Feb. 2014. http://www.pethealthnetwork.com/dog-health/dog-toxins-poisons/lead-poisoning-dogs-and-cats.
Park, S. H., M. H. Lee, and S. K. Kim. “Studies on the Concentrations of Cd, Pb, Hg and Cr in Dog Serum in Korea.” Asian-Australasian Journal of Animal Sciences 18.11 (2005): 1623-627. Web. http://www.ajas.info/journal/view.php?number=21167.
Originally Posted: February 8, 2016; Updated: June 4, 2024