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Showing posts with label sampling. Show all posts
Showing posts with label sampling. Show all posts

Thursday, December 5, 2019

A Breath of Fresh Air

If you like fresh air, you're probably a big fan of the Clean Air Act and its amendments. While the air in many places is far from ideal, prior to federal legislation it was downright deadly in American cities. A clear gray sky on a summer's day in Philadelphia is a little off-putting, but it beats a smothering fog in the valleys outside Pittsburgh. After the deadly Donora smog in 1948 killed 20 and sickened thousands of others. Federal investigators were asked to come in, and determined that air pollution was in fact the killer, among other factors.
Donora smog, 1948 (Smithsonian)
The government prefers to take baby steps when implementing positive change, rather than jumping in feet first, and tackling air pollution is no exception. The first step came in 1955 with the Air Pollution Control Act, which provided funding for research and led to the Clean Air Act of 1963 and Air Quality Act of 1967. These provided the first air quality monitoring.
Pittsburgh in the 1940s (Citylab)
The Clean Air Act of 1970 was a major step forward. It developed limits on pollution and expanded federal enforcement powers. Among the controls included were auto emissions. States were mandated to implement plans to reduce pollution.
The Amendments of 1990 aimed to reduce air pollution linked to acid rain and ozone depletion.
Looking at a picture of the summer sky over Los Angeles, it might be hard to believe the Clean Air Act is working. However, the number of ugly sky days is lower than prior to enactment. Air quality monitors in California frequently show poor quality, and geography is partly to blame. Ocean breezes carry pollution as far as the mountains, where it gets stuck and sometimes builds up for days.
Los Angeles skyline (LAist)
Acid rain has been reduced as a result on the 1990 amendments. pH testing has shown freshwater pH levels in many areas have risen closer to neutral 7. Pure water is neutral, but in nature, water is rarely pure. Pristine rain is slightly acidic because of carbon dioxide in the atmosphere forming carbonic acid. However, the lowered pH in rivers and lakes nationwide was far lower than caused by carbonic acid. Targets of the 1990 amendments were nitrogen oxides (NOx) and sulfur dioxide (SO2). Emissions have been greatly reduced over the last 30 years, and ecosystems are continuing to slowly recover.

Visuals of higher pH meaning less acidic water samples
(National Atmospheric Deposition Program)

Information this week comes the EPA (Clean Air Act overview), Smithsonian Magazine (Donora), and more EPA (acid rain). For a great visual on showing higher pH and lower NOx and SO2, check out the National Atmospheric Deposition Program.

EPA: https://www.epa.gov/clean-air-act-overview/evolution-clean-air-act
Smithsonian: https://www.smithsonianmag.com/history/deadly-donora-smog-1948-spurred-environmental-protection-have-we-forgotten-lesson-180970533/
EPA: https://www.epa.gov/airmarkets/acid-rain-program
nm1 LAist: https://laist.com/2018/10/30/why_las_smog_has_been_extra_smoggy.php
nm2 Citylab: https://www.citylab.com/design/2012/06/what-pittsburgh-looked-when-it-decided-it-had-pollution-problem/2185/
nm3 Smithsonian
nm4 National Atmospheric Deposition Program http://nadp.slh.wisc.edu/data/animaps.aspx

Friday, November 3, 2017

Live Streaming

After so many stories from the road, this little story about one of my last events in Washington got shoved aside. I spent some time in Percival Creek with the Thurston County Stream Team conducting a stream bug survey, also known as a biological index of benthic invertebrates (BIBI). File this under “Things I wasn’t allowed to do 30 years ago”.

Stream bug monitoring is an important way to gauge the health of a stream. Some thrive in polluted water, some thrive in pristine water. To know how many of which kinds of insects are in the stream is a good indicator of water quality. Just what is a stream bug? The ones we looked for are actually the larvae of insects such as mayflies and caddisflies. The larvae are aquatic, living in freshwater, making a living in a variety of ways such as scrapers and shredders.

The method used by my group was to sample three areas within a riffle of the stream. A riffle is an area of faster moving water. Our leader, Debbie Smith, is the coordinator for Tumwater Stream Team. She supplied us with all the necessary equipment, minus our own boots. To collect samples, we used a funnel-shaped net that had a metal square at the front which marked the boundary of the sampling area. A weed fork is a great tool for the stream to, scaring up bugs on the rocks and in the substrate by rapidly mixing it around inside the metal square. Debbie also brought a stop watch, buckets, insect field guides, and lab equipment including magnifying glasses, headlamps, forceps, and sealed containers. While we began collecting samples, Debbie stayed behind with one other from our group to set up the lab. 
Net similar to the one we used for sampling. The front section defines the sampling area.

Weed fork

After washing our boots in a mild chemical solution, we took turns mixing up both the surface and substrate of the stream bed for a minute, loosening the bugs which then flowed into the net with the current. Large rocks in the square went into a bucket for analysis. Stream width and depth at the sample sites, as well as the length of the sampled riffle, were recorded for each sample. Distilled water (to prevent outside bugs from being counted in the sample) was used to rinse any bugs on the net into the collection bag at the bottom. 
Example of stream bugs clinging to a rock

Processing samples in the lab (Debbie Smith photo).

Our samples were taken to the lab for analysis. Our lab was a simple setup on a bridge that day. Small rocks in the collection bag were removed and inspected. Any bugs were removed with forceps and placed in alcohol for later analysis by entomologists that can ID them by genus and species. The same was true for the large rocks in the bucket. The collection bag was emptied and scoured for bugs. Rocks were not sent to the entomologists, but any organic matter in the net, such as leaves and woody debris, did go along with the insect samples. We did this at three different riffles, for a grand total of nine minutes of churning up creek bed.


We did our survey in because stream levels are low. If the water is too high, the bottom is unreachable and the current can be dangerous. There were always at least four of us in the water: one holding the net, one using the weed fork, one running the stopwatch, and one holding the bucket of rocks. If anything happened to one of us, there was always someone available to help. Always think safety in the lab and in the field. 
Stream Team following a successful morning of splashing around
Percival Creek. I am 4th from the left in the green shirt.
(Debbie Smith photo)