How much wastewater is dumped into the ocean?
Historically, the effects of wastewater pollution have been associated with human health; however, the detrimental effects of wastewater pollution on marine life—and the indirect effects they have on people—must not be overlooked. Wastewater carries pathogens, nutrients, contaminants, and solids into the ocean, where they can cause coral bleaching as well as disease and mortality in coral, fish, and shellfish. Pollution from wastewater can also change ocean temperature, pH, salinity, and oxygen levels, interfering with biological processes and physical environments critical to marine life.
There's also the problem of microplastics leaking into waterways from wastewater treatment plants. Fish are harmed by additives that remove microplastics, but microplastics themselves are harmful because they hold onto chemicals that harm fish.
Exposure to Pathogens
Wastewater pollution exposes corals to pathogens, which are disease-causing viruses, bacteria, or other microorganisms. Water pollution has been linked to outbreaks of two of the most common coral diseases, white pox and black band disease. White pox is caused directly by the human gut pathogen Serratia marcescens, whereas black band disease is strongly associated with increased macroalgal cover in polluted waters.
Nutrients are the building blocks of marine life. Excess nutrients from land-based sources of pollution, such as agricultural runoff and wastewater, cause coral bleaching and disease, decreased coral reproductivity, decreased coral skeletal integrity, decreased coral cover and biodiversity, increased phytoplankton shading, and algal overgrowth in the marine environment. Shellfish take in pathogens and other pollutants as they filter nutrients from the water for shell and tissue formation. Excessive contamination can cause shellfish health to deteriorate. Ongoing nutrient loading and the resulting algal blooms can devastate coral reefs and coastal ecosystems, and the frequency and scale of these events are expected to increase as a result of climate change.
Other Contaminants and Solids
Wastewater also contains suspended solid materials that float in the water, such as decomposing plant matter, algae, minerals, and silt. These solids can do the following in the ocean:
1: Light is blocked-These solids float in the water and block the sun's rays. Depending on how much and how long the solids remain, this can lead to decreased photosynthesis and coral growth.
2: Corals in distress-When these solids settle on corals, they cause physical stress such as suffocation, decreased food production, and decreased reproduction.
3: Filters become clogged-Shellfish consume suspended particles, which clog their filters.
4: Reduce water clarity-Reduced water clarity also makes it more difficult for fish to find food and can interfere with reproduction.
Contaminants of Emerging Concern
(CECs) are pollutants in water bodies that have the potential to harm the environment or human health, but are not typically regulated under current environmental laws.
Agricultural chemicals, urban runoff, common household products (such as soaps and disinfectants), and pharmaceuticals are all sources of these pollutants. CECs are found in higher concentrations and more frequently in treated wastewater effluents, and many have been shown to accumulate in the tissues of marine life.
Endocrine disruptors, or compounds that have an effect on the endocrine system, are particularly dangerous type of CECs. These include hormones that occur naturally or are synthesized, as well as chemicals used in textiles, plastics, household products, and agriculture. The following are some of the ways that these pollutants harm marine life:
1: Antidepressants have been shown to influence fish behavior and cause mortality at low concentrations.
2: Synthetic hormones and endocrine disruptors, such as estrogen from birth control pills or parabens in soap, can impair reproduction and contribute to aggressive behavior in fish.
3: Endocrine disruptors that bio-accumulate in fish tissues.
4: Endocrine disruptors reduce the number of egg-sperm bundles and growth rates in corals.
For wastewater or sewage of any kind, Netsol Water offer a complete spectrum of wastewater treatment products. Our engineers would gladly collaborate with your team to create the right design that meets your budget and objectives.