Boric Acid and Lumbriculus Variegatus Jonathan Trembley and Michael Welles, GCC Bio 100 Introduction: Lumbriculus Variegatus is a fresh water worm found in the shallows of North America and is more commonly referred to as the California Black Worm. It’s clear body and easily readable pulse rate allows researchers to readily measure the effect of environmental conditions on its vital signs. This capability promotes toxicological research to predict the effects of various chemicals on the living organisms in an ecosystem and on humans. Boric Acid is an inorganic salt (H3BO3) used for cockroach and ant control. It is used for weatherproofing wood, fireproofing fabrics, externally on humans as an antiseptic, eye ointment, and antibacterial agent, and extensively in industry for cements, glass, leather products, carpet, soaps, cosmetics, dyeing, printing, painting, and photography. Because of its wide use, the possibility of it accidently arriving in the environment of Lumbriculus Variegatus is high. Due to this risk, the effects of the acid should be tested to determine if the organism is at risk from the toxin. The acid has already been proven to cause reproductive damage, but the effects of the acid on the respiratory system of the black worm have not been tested. If the environment of the common black worm is intoxicated with boric acid, the pulse rate of the organism will be less than that of a black worm in an unadulterated environment. Method: 1) In three-minute increments, transfer one black worm from the housing container to a spring water filled petri dish until all are filled with a single worm. 2) Concurrently, after a worm has been in the individual boat for five minutes, place the organism on the pre-prepared well slide and cover with cover slip. With compound microscope on low power, count number of pulses in 30 seconds and multiply by two for pulses per minute. Record value. 3) Once worm has been on microscope for 1 minute weather a value has ben recorded or not, the worm should be placed in a recovery well and not tested again this day. 4) Repeat step 2 until 10 values for spring water pulses per minute have been recorded. Repeat steps 1, 2, and 3, replacing spring water with.5M,.1M, and.05M solutions of Boric acid. Sources: Drewes, C. (n.d.). Biological smoke detectors: a toxicology primer for student inquiry. Retrieved September 12, 2013fromhttp:// web3.PDFhttp:// web3.PDF (n.a.). (n.d.) Boric Acid Technical Fact Sheet. Retrieved October 2, 2013 from Results: The average pulse rate in spring water was 13.3 bpm. The average pulse rate in.05 molar acid was 13.8 bpm. The average pulse rate in.1 molar acid was 14 bpm. The average pulse rate in.5 molar acid was 11.4 bpm. The pulse rates were highest in the.1 molar acid and decreased as molarity decreased but were lowest in the.5 molar acid (greater than.1). Conclusions: The data did not support the initial hypothesis but promoted the opposite. Although the averages of the.1 molar and.05 molar pulse rates are only slightly higher than that of the spring water solution, they are greater, and logically, the.1 molar pulse rate is higher than that of the.05 molar; therefore, the boric acid must act as a minor stimulant at non-lethal concentrations: possibly, the greater the concentration, but still non-lethal, the greater the effect on the pulse rate. The.1 molar and.05 molar concentrations were determined non-lethal by keeping some black worms in the acidic solutions for more than five minutes. This produced higher pulse rates than the average but never a fatality. However, in the case of the.5 molar, the concentration was most definitely fatal; any worm kept in the solution for more than seven minutes died. This lethality explains the lower pulse rate of the.5 molar. Although each worm recovered, the solution was killing them, aka decreasing the pulse rate to zero. Therefore, it is logical that the pulse rate of the worms in the.5 molar should be lower than the control group.