How much Baltimore stream water do you need to drink to get high?

amphetamine-streams.ipynb

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    "# How much Baltimore stream water do you need to drink to get high?\n",
    "\n",
    "#### By Daniel Himmelstein\n",
    "\n",
    "A recent study reported high concentrations of amphetamine in Baltimore's streams:\n",
    "\n",
    "> Lee SS, Paspalof AM, Snow DD, Richmond EK, Rosi-marshall EJ, Kelly JJ (2016) [**Occurrence and Potential Biological Effects of Amphetamine on Stream Communities**](https://doi.org/10.1021/acs.est.6b03717). _Environmental Science & Technology_. DOI: 10.1021/acs.est.6b03717\n",
    "\n",
    "CNN [covered the study](http://edition.cnn.com/2016/08/25/health/meth-fish-baltimore/index.html \"CNN Health: Your drain on drugs: Amphetamines seep into Baltimore's streams\"). The study and especially the CNN piece suggest that execretion from illicit amphetamine users is the source of contamination. I am skeptical of these claims, as I explained [on PubMed Commons](http://www.ncbi.nlm.nih.gov/pubmed/27513635#cm27513635_26614).\n",
    "\n",
    "The study found a high concentration of amphetamines at Gwynns Run at Carroll Park in Baltimore (630 ng/ml). To see just how high this concentration is, we'll calculate **how much stream water one would need to drink to receive an effective dose of D-amphetamine** (5 mg). Credit to Kamen Simeonov and Benjamin Emert who [did this analysis first](https://twitter.com/dhimmel/status/769568322723647488 \"Tweet\") by hand. Note that the original version of this analysis mistakenly used milliliters rather than liters as the denominator for unit stream concentration."
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   "source": [
    "# Pint is a package for physical quantities in Python\n",
    "import pint\n",
    "u = pint.UnitRegistry()"
   ]
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       "630.0 nanogram/liter"
      ],
      "text/latex": [
       "$630.0 \\frac{nanogram}{liter}$"
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       "<Quantity(630.0, 'nanogram / liter')>"
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   "source": [
    "# Stream concentration\n",
    "stream = 630 * u.ng / u.l\n",
    "stream"
   ]
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       "5 milligram"
      ],
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       "$5 milligram$"
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      "text/plain": [
       "<Quantity(5, 'milligram')>"
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     "execution_count": 3,
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   ],
   "source": [
    "# Effective dose of D-amphetamine\n",
    "dose = 5 * u.mg\n",
    "dose"
   ]
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   "source": [
    "# How much stream is needed for an effective dose\n",
    "drink = dose / stream"
   ]
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   "execution_count": 5,
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     "data": {
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       "7936.51 liter"
      ],
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       "$7936.51 liter$"
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       "<Quantity(7936.51, 'liter')>"
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     "execution_count": 5,
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   "source": [
    "# Show in liters\n",
    "round(drink.to(u.liter), 2)"
   ]
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   "execution_count": 6,
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     "data": {
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       "2096.6 gallon"
      ],
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       "$2096.6 gallon$"
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   "source": [
    "# Show in gallons\n",
    "round(drink.to(u.gallon), 2)"
   ]
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   "source": [
    "#### How about the artificial streams?\n",
    "\n",
    "In the study, Lee et al created artificial streams to evaluate the environemntal dangers of amphetamine runoff. Their articial streams had a concentration of 1 ug/ml. To assess the potency of their artificial stream, here is how much you would have to drink for an effective dose:"
   ]
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   "source": [
    "drink = dose / (1 * u.ug / u.l)"
   ]
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   "cell_type": "code",
   "execution_count": 8,
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     "data": {
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       "5000.0 liter"
      ],
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       "$5000.0 liter$"
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       "<Quantity(5000.0, 'liter')>"
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     "execution_count": 8,
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   "source": [
    "round(drink.to(u.liter), 2)"
   ]
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       "1320.86 gallon"
      ],
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       "$1320.86 gallon$"
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       "<Quantity(1320.86, 'gallon')>"
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   "source": [
    "round(drink.to(u.gallon), 2)"
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   "source": [
    "## Sewage (wastewaster) contentration"
   ]
  },
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       "9.91 microgram/liter"
      ],
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       "$9.91 \\frac{microgram}{liter}$"
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      "text/plain": [
       "<Quantity(9.91, 'microgram / liter')>"
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     "execution_count": 10,
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   "source": [
    "# Assume 1 in 4 people consumes 30 mg of AMPH per day\n",
    "daily_consumed_amph = 30 * u.mg * 0.25\n",
    "# Assume 40% of AMPH is excreted\n",
    "daily_excreted_amph = 0.4 * daily_consumed_amph\n",
    "# Assume each person's excrement is dilluted in 80 gallons of wastewater per day \n",
    "# Source http://water.usgs.gov/edu/qa-home-percapita.html\n",
    "daily_water = 80 * u.gallon\n",
    "# Calculate the average concentration of AMPH in sewage\n",
    "sewage_concentration = daily_excreted_amph / daily_water\n",
    "round(sewage_concentration.to(u.ug / u.l), 2)"
   ]
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   "source": [
    "## Disclaimer\n",
    "\n",
    "I don't recommend consuming Baltimore stream water (either medicinally or recreationly) as the study states:\n",
    "\n",
    "> As much as 65% of the average flow in the Gwynns Falls can be attributed to untreated sewage from leaking infrastructure."
   ]
  }
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