[Braxton1980]

Would Eurofins be able to set up monitoring on Tesla's property?

What other sources would have similar pollutants to a Lithium factory? It seems pretty specific and if there was some other obvious source why wouldn't Tesla point that out?

[ggreer]

Hexavalent chromium can come from many industrial sources, including welding stainless steel. If you go to Tesla's lithium refinery in google maps[1] and follow the drainage ditch along highway 77 (to the northeast) about a half mile, you'll see a company called Tex-Isle Processing. They supply steel pipes and coating services for oil drilling.[2] It could be that one of their manufacturing processes creates hexavalent chromium.

In my opinion there isn't enough information to blame anyone for the slightly-above-drinking-water levels of hexavalent chromium. The drainage ditch goes along a highway and a rail line, so pollution could come from all kinds of places.

1. https://maps.app.goo.gl/7iNTbiPcs1sZ9CqP8

2. https://www.texisle.com/

[bloaf]

Something else to note:

The lab tested for chromium in two ways: one test (ICP) measures all chromium of any kind, and the other measures hexavalent chromium specifically. The ICP test returned a concentration that was an order of magnitude smaller than the hexavalent test (0.0003 vs 0.0104 mg/L). That is to say, the tests contradict each other (because the whole is smaller than the part).

https://www.documentcloud.org/documents/28055380-j2673-1-uds...

[xg15]

Ok, that's one of the pollutants...

But I agree, measuring at the end of the ditch was the wrong thing to do if they take issue with that specific factory (though it was the right thing to do to prove a harmful pollution exists in general)

So another measurement directly at the pipe would be in order.

[ggreer]

The measured levels of arsenic, strontium, and vanadium are below the limits for drinking water, even in California. And 4% of drinking water sources in California have higher hexavalent chromium content than the water in that ditch.[1] Besides sodium from salt, the only metal that was particularly high was lithium, at 0.0714mg/L or 71 micrograms per liter. A significant fraction of drinking water in the US has higher concentrations than that.[2]

The level of salt shouldn't affect much. Adding up the chloride and sodium content gets you 684mg/L, which is on the low end of brackish water (500-30,000mg/L). The limit for agricultural irrigation is 2,000mg/L, and photos of the pipe show plenty of grass growing around and in the water.

The phosphorous could come from fertilizers, as there's plenty of farm land in the area. That would also explain the higher ammonium levels, as both anhydrous ammonia and ammonium phosphate are common fertilizers.

The article is really about how sensitive our scientific instruments are, not how dangerous the water is. It reminds me of articles like Vice's American Honey Is Radioactive from Decades of Nuclear Bomb Testing[3], where the most radioactive honey they could find was 10 times less radioactive than a banana.

1. https://www.waterboards.ca.gov/drinking_water/certlic/drinki...

2. https://www.sciencedirect.com/science/article/abs/pii/S00489...

3. https://news.ycombinator.com/item?id=26906838

[wongarsu]

They list 6 pollutants, but only two of them seem relevant to the legality of this.

One is an amount of arsenic that is a quarter of what's allowed in drinking water. So technically, someone dumping drinking water in the ditch could contaminate this measurement.

The other is hexavalent chromium, which is 4% higher than allowed. According to wikipedia that is "indeed one of the more widely used heavy metals in various sectors and industries (metallurgy, chemicals, textiles, etc.) with particular involvement in the metal coating sector" and used in the production of all kinds of dyes, paints, plastics, etc. It can also be formed by welding stainless steel, and is found in drinking water ... that doesn't sound very specific to me.

I don't know where that ditch is, but on google maps the Tesla lithum plant is right next to a place storing drilling equipment outdoors. Runoff from any kind of industry nearby could end up in that ditch. After all, collecting runoff is what ditches are there for

[defrost]

> collecting runoff is what ditches are there for

Sure. What ditches aren't for, and vary greatly wrt, is discharging all inputs out to sea or or a large body of water for "sufficient" dilution.

Ditches can be sealed (concrete lined, with a membrane underneath) or, say, just dirt.

Dirt ditches with a long run filter .. heavier particles drop out, weeds and other organics grab onto various compounds, etc. Those things that filter out and layer into a ditch and can then concentrate over time (subject to terms and conditions).

A reasonable question, that should be asked of any industrial area, is whether dirt ditches, leaky pipes, the whole deal, are accumulating toxins over a decade or more ... and what the impact and remediation plan is for that.

Worst case, ditch line concentrates leach down into a water table close enough to an extraction pump that goes to water food or be drunk by people. (Or later in time earthworks for housing kick up a dust layer that just happens to be mostly "20 years of bad ju-ju")

Not insurmountable, something to be wary of, these things have happened.

[cucumber3732842]

>Worst case, ditch line concentrates leach down into a water table close enough to an extraction pump that goes to water food or be drunk by people. (Or later in time earthworks for housing kick up a dust layer that just happens to be mostly "20 years of bad ju-ju")

Pretty much all water discharge rules are built around filtering stuff out. I thought we wanted it in the dirt so it would't be in the water?

The part that drives me up the wall is the two faced capricious nature of all this.

I have a grass parking lot and everyone screeches about tire rubber concentrating in the dirt.

I pave the lot and everyone screeches about the rubber in the runoff

I pay an engineering firm to say that my grass strip on the side of the paved parking lot is an engineered feature that per their calculation will catch yada yada yada blah blah blah and I get my permit.

Seems to me like you can't put anything anywhere. You just go in circles until you've the right rings for the right amount and then they say "this is fine".

Whether the ditch is dirt and grass (nature's filter) or lined with something, hexavalent chromium is just the big boy big dollar version of the same stupid parking lot problem.

Say they filter the chromium out. So then it winds up concentrated in something. Where does it go then? Seems like the only way to permanently deal with waste is to sell it into another jurisdiction where the buyer has kissed the right rings to let it be used as some input to some other process where it then goes from waste to something else.

[defrost]

Sewerage discharge pipes are ideally built to take post processed human waste residues far enough out to sea to not be trapped in small bays but to disperse and diffuse through a greater volume of water.

The ideal here might be (I haven't dug into site specific details here) to take any industrial runoff far out to a large volume of water so that it can disperse and not be concentrated in a manner that creates a time bomb for human food / water inputs.

If that is the intent, then unsealed ditches crossing watersheds is a bad idea compared to sealed pipes with deep water discharge.