within the eutrophic range and have dramatically improved through extensive monitoring and remedial works addressing both point source and non-point source nutrient loading (51). Overall TP readings in the GBBR have experienced a lowering trend since the mid to late 1980’s (41). That trend has likely slowed or reversed in many embayment and tributary areas that have seen increased development, human land use and access (51). The above TP data is exclusive to the Georgian Bay portion of the GBBR, whereas the biosphere reserve also contains many small inland lakes and tributaries. Many of these have shores and drainage basins well-populated with cottages, seasonal resorts, recreational and agricultural activity and, therefore, likely experiencing elevated TP levels far above those that would exist under the exclusive influence of natural processes (41). Total Phosphorus as its name implies is a reading taking into consideration multiple sources and types of the element including inorganic phosphorus, particulate organic phosphorus and dissolved phosphorus (52). Sources of phosphorus in freshwater bodies come from both natural processes and human activities. Natural phosphorus loading occurs when phosphorus contained in rock erodes and is carried in sediment form with overland flows through undeveloped/natural areas or as atmospheric particulate within precipitation (41). Significant gaps exist in the data available on Total Phosphorus, including readings for inland lakes and tributaries, for many of the less-accessible embayment areas in the northern reaches of the biosphere reserve, and also for baseline data-sets with the potential to identify change patterns (25). It is also unclear precisely what portion of overland-flow phosphorus loading is the result of human use and disturbed landscapes, verses natural areas and what portion may be due to outdated, malfunctioning, or damaged septic systems and waste water treatment facilities (25).
CHEMICAL POLLUTANTS entering the Great Lakes are remarkably persistent in lakebed sediments over time and are regularly disturbed by ship propellers, bottom foraging aquatic species, and dredging activity, causing pollutants to re-enter the food web. Toxic chemicals can be categorized as: biomagnifying toxic metals (ex. Mercury), non-biomagnifying toxic metals (ex. copper), biomagnifying toxic organics (ex. PCBs, Atrazine, neonicotinoid pesticides) and non-biomagnifying toxic organics (ex. PAHs). Although much progress has been made over the last 20 years toward dramatically reducing the blatant use of the Great Lakes and tributaries as a dump for chemical waste, some industries still maintain permits to pollute, while old toxins persist in the system. Toxins continue to enter the lakes with chemicals of emerging concern originating from discarded products that waste water treatment facilities are incapable of removing. Non-point source pollution including agricultural and golf course pesticide applications leeching through soils, and air-born mercury
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