Understanding water quality

Overall. the Delaware Bay fares better than most estuaries including the Chesapeake Bay to the southwest and the Barnegat Bay to the northeast

Water quality monitoring measures potential contaminants that fall into three categories: chemical and nutrient. and bacterial. A overly simplistic way to think of it is that chemical contaminants come from factories, nutrient contaminants come from farms and bacterial contamination comes from untreated sewage.


Here in the Delaware Bay we are concerned with only one type of chemical containment. PCBs have settled into the waterbed and are found in trace amounts throughout the system. These chemicals are known to cause cancer and other health problems in humans. While PCBs are not harmful in the diluted amounts found in the  water,  the problem is that they build up and concentrate in fish tissues where we can ingest the higher and possibly more dangerous amounts,

PCBs are man-made chemicals that were used in electrical equipment like capacitors and transformers. Polychlorinated biphenyls (PCBs) are oily liquids or solids, clear to yellow in color, with no smell or taste. The good news is that we don’t make them and pollute our water with them anymore. That means that the other good news is that the level of PCBs is going down in the Delaware Bay. The bad news is that they are everywhere in the environment,  last a long time, and are almost indestructable. PCBs are stable and remain in the environment at low levels for many decades,. However, the chemical is found to concentrate inside fish tissue, especially the fatty portion.

Both New Jersey and Delaware issue advisories limiting the recommended amount of fish that should be eaten.


The primary nutrient pollutant is nitrogen. Over abundance of nitrogen leads to low levels of water oxygen and fish kills. Nitrogen comes from fertilizer and farm runoff. When we discuss “water pollution” in the Delaware Bay, the discussion is focused on nutrients.


Several strains of potentially dangerous bacteria live in the Delaware Bay and they reach potentially harmful levels in summer. The bacteria we hear most about is E. coli from untreated bird, human or animal feces. Birds are the primary contributor of E. coli in the Delaware Bay occasionally after a storm or flood the source is identified as human. In these cases shellfish harvesting is temporarily halted. Our bay water at Money Island is tested regularly for E. coli and no problems lately. Other types of bacteria can cause infection of open wounds. It is important to clean and disinfect skin abrasions when working in or around the bay, especially in summer.

Overall our water quality compares well to surrounding waterways and is gradually improving.

What does all of this mean to us? It is pretty simple:

  1. follow shellfish harvesting rules
  2. Don’t consume too much of some fish species
  3. Clean and disinfect wounds.

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