Obviously, a big concern on this website is food waste: food that goes uneaten and gets unsustainably disposed of due to negligence. However, as part of the ongoing series on the consequences of the meat industry (here are posts one and two), this post is going to focus on livestock waste. This type of waste includes all discards and excrement generated by animal agriculture, including: manure, urine, carcasses, feed remnants, bedding, and feathers. In addition to being merely unpleasant, the mishandling and sheer quantity of these outputs causes a lot of dangerous contamination.
In 1999, the General Accounting Office reported that livestock generated 130 times as much waste as humans in the US. The amount of waste produced on farms greatly exceeds that which can be used to fertilize the fields, so much of the excess is transported – with great difficulty, risking spillage – to open, man-made pits known as lagoons.
Settling in these lagoons, the liquid manure can leak into surface water and groundwater directly or via run-off. While the fecal matter itself can be hazardous, manure also carries many heavy metals, such as arsenic and antibiotics, and pesticides present in animal feed. These adversely impact soil and water quality with excess nutrients, especially nitrogen and phosphorous. Manure also emits the three primary greenhouse gases, CO2, methane, and nitrous oxide, as well as the hazardous gas ammonia. With over 70 billion farm animals being raised each year, the cumulative impact of their excrement is quite problematic. Steinfeld et al. calculated that livestock farming (including more than just waste, admittedly) accounted for 18% of global greenhouse gas emissions in 2006, surpassing those of the transportation sector.
Of course, the effects of contamination don’t stop with the soil, water, and air themselves. High nitrate concentrations can turn drinking water toxic to infants, while high heavy metal content has been known to cause cancer, circulatory complications, and organ and nervous system damage. Meanwhile, compounds like ammonia in manure gases can hurt animals’ lungs and increase their risk of developing pneumonia when stored in improperly ventilated areas. Farm workers are at similar risks through prolonged exposure to the hazardous gases and odors of animal waste, and up to 30% develop asthma or bronchitis. Finally, the waste often carries pathogens that can cause diseases like salmonella – but I think I’ll save those for next week.
Lower demand for meat, fewer animals raised as livestock, less waste, healthier planet – is this enough to convince people to eat less meat? Or should we focus on dealing with our waste better, rather than just letting it sit around? Given the evidence, I think we need a dual strategy.
Horrigan, Leo; Lawrence, Robert S.; and Walker, Polly – How Sustainable Agriculture Can Address the Environmental and Human Health Harms of Industrial Agriculture
Walker, Polly et al.– Invited Paper: Public Health Implications of Meat Production and Consumption