Introduction to ICP-MS testing of gravity water filters conducted by Mike Adams, the Health Ranger
Unlike most scientific papers, this abstract is intentionally written in the first person point of view. I am the person who actually conducted the tests, so it only makes sense to describe the process from this perspective.

Through the Spring and Summer of 2014, I purchased five of the most popular off-the-shelf gravity water filters which are commonly promoted and sold as emergency water filtration devices. For this test, I limited my purchase only to those filters which are non-electric and operate from the principle of gravity. In other words, no water filters with manual pumps were included.

The purpose of this testing was to subject each water filter to a known concentration of heavy metals contaminants (lead, cadmium, arsenic, mercury) as well as elements which have radioisotopes such as strontium, cesium and uranium. Aluminum was also tested, but fluoride was not tested due to the difficulty of running halogens through ICP-MS sample introduction systems. (We have a different way to test fluoride using another instrument, but its accuracy is nowhere near the ppb accuracy of ICP-MS.) Water filters were not tested for pesticides, herbicides, PCBs or other complex molecules. Also, the filters were not tested for removal bacteria, amoeba or other microorganisms.

In preparation for the tests, I created a "cocktail" of heavy metals using NIST-traceable external standards purchased from Inorganic Ventures. Each gravity filter was prepared for testing by first being flushed with its maximum holding volume of laboratory-grade deionized (DI) water, produced from a laboratory instrument manufactured by Thermo Scientific.

Once the initial flush was completed, each water filter was then filled with the heavy metals cocktail and gravity filtration was allowed to commence. Samples were taken of this "pre-filtered" water in order to compare it to the "post-filtered" results for each water filter.

After the completion of the gravity filtration, which required anywhere from 8 - 24 hours depending on the unit, the resulting water was sampled and tested via ICP-MS in the Natural News Forensic Food Lab, where I am the laboratory director.

This lab is ISO accredited and uses EPA-derived methodologies for sample preparation, acid digestion, normalization and ICP-MS introduction. Mid-run calibration standards are always used, and I also use 4-point multi-elemental calibration curves for each run with robust RSDs that provide very high confidence of accuracy variance within + / - 5% of reported numbers.

Summary of Findings:

The gravity water filter brands tested were:

Big Berkey
Zen Water Systems
Crystal Drop

Performance of the filters varied significantly, with some units achieving a near-100% removal rate of toxic elements (Big Berkey and Zen Water Systems) while other units showed very little ability to remove toxic heavy metals at all (Doulton).

Many units tested actually increased the level of aluminum in the filtered water. Crystal Drop filters released the most aluminum into the filtered water. ProPur filters increased aluminum by 92%, but the new "All-in-One" ProPur filters reduced aluminum by 61%. Doulton filter elements also released aluminum into the water. (Aluminum is commonly used in water filtration elements because of its flocculant properties.)

Even after flushing, ProPur's new "All-in-One" filter elements left behind a cloudy residue in the bottom of the filtration receiver. This liquid was sampled and found to contain 50 ppm of Aluminum, indicating a strong need to repeatedly flush these elements before using them to produce potable water. Big Berkey, the most prominent competitor of ProPur, did not suffer from this problem and produced extremely clean water after a single flush.

All water filters used in this test have been physically stored for future analysis. Water samples taken during the test have also been archived for future verification, if needed.


Big Berkey and Zen Water Systems produced by far the best results in these tests, removing nearly 100% of most toxic elements.

ProPur performed far worse than expected, with the older ProPur elements achieving surprisingly low reduction in toxic elements. But the new "All-in-one" ProPur elements performed significantly better, although the numbers are still far from the performance of Big Berkey.

Crystal Drop and Doulton filters performed very poorly, failing to remove significant quantities of toxic elements in our tests.

Full Disclosure:

Keep in mind that Natural News gets paid nothing to conduct these tests. The testing is a public service, offered to the public free of charge, and costing surprisingly large amounts of money to conduct in terms of product acquisition costs and laboratory operating costs. (The lab itself cost over $1 million to build.)

Even before we began testing all the various brands of gravity water filters, I knew in advance that we wanted to form an affiliate relationship with whatever water filter turned out to have the best performance. Because of marketing claims circulated about these products, it was my belief that ProPur was going to turn in the best performance, and I thought that Big Berkey would come in second. However, I set all this aside and let the test results speak for themselves.

When all the testing was done and the results were in, it was immediately apparent that Big Berkey was by far the superior filter for the removal of the toxic elements we were testing. Zen Water Systems came in second and ProPur was third. Upon learning these results, Natural News formed an affiliate relationship with Big Berkey to publicize their filters on our preparedness websites (such as, earning a relatively small affiliate fee from each sale. We sat on the testing results data for probably two full months before finally getting this website launched. The delay was caused by the Ebola outbreak dominating the news cycle.

I feel very good about the integrity of our process of testing and then selecting a water filter to represent, knowing that I waited for the lab results before choosing an affiliate partner and knowing that we are now promoting the filter which clearly has a superior ability to protect consumers from toxic elements. Unlike other promoters who conduct no laboratory testing whatsoever, we meticulously tested every popular filter brand on the market before deciding what to recommend.

I have seen other promoters boast very loudly and aggressively about how their water filters are the best in the world, but I have never seen them conduct any testing at all. So how could they possibly know? This is a case where the science beats the hype. Because of my personal integrity in product selection and marketing, I will only promote a product which I have scientifically tested and verified to be the most superior available in the world. This is also true with our supplements and superfoods which are meticulously tested via ICP-MS for heavy metals contamination (and about 80% of raw materials are rejected by us because of contamination issues).

Also for the record, neither myself nor Natural News received any compensation nor free product for conducting these tests. All products were purchased at retail, via No attempt was made to request payment of any kind from the manufacturers of these products for the testing conducted here. I am aware there are other labs that conduct similar tests and then request payment from manufacturers, but we do not pursue such arrangements.

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