Human Health Use (Fish Tissue)
Fish tissue data was available for approximately half of Ohio’s watershed assessment units and one-third of publicly-owned lakes. About one-third of monitored watershed assessment units and two-fifths of monitored lakes were unimpaired for this use. PCB contamination, primarily a result of historic industrial sources and old landfill discharges, is the cause of most of the human health use impairments. Mercury is the second leading cause of human health use impairments after PCBs.
For Lake Erie public beaches, the frequency of swimming advisories varies widely, ranging from near zero at South Bass Island State Park and Battery Park beaches to over 40 percent at Arcadia, Bay View West, Edson Creek, Euclid State Park, Lakeshore Park, Lakeview, Sherod and Villa Angela State Park beaches. Generally, beaches located near population centers tend to have the most problems.
For inland streams, approximately half of the total assessment units had sufficient data to determine the recreation use assessment status in 2016. Of the watersheds assessed, 10 percent fully supported the use while 90 percent did not. Increased bacteria levels are often observed during periods of higher stream flows associated with heavy rains. Although not sampled as frequently as streams or Lake Erie beaches, bacteria levels at most inland lake beaches do not frequently exceed the threshold, resulting in fewer postings compared to some of the beaches along Lake Erie.
Aquatic Life Use
Ohio’s large rivers (the 23 rivers that drain more than 500 square miles) reflected a small decline in percent of monitored miles in full attainment compared to the same statistic reported in the 2014 Integrated Report. This is due to the inclusion of new data from two rivers considered historical status (i.e., previous data not used) in past reports. Both had been greatly impaired in the past, but are now showing vastly increased miles meeting goals. However, the percent of miles remaining impaired slightly lowered the overall large river full attainment statistic.
Based on monitoring through 2014, Ohio’s large river assessment unit full attainment statistic now stands at 87.4 percent (down 1.8 percent from the 89.2 percent that was shown in the 2014 report). The table below shows the status of the four large rivers recently sampled, particularly the improvement in the Maumee and Tiffin Rivers since the mid to late 1990s.
Public Drinking Water Supply Use
There are a total of 119 public water systems using surface water (excluding Ohio River intakes). Sufficient data were available to evaluate 43 percent of the drinking water source waters for nitrate.
The only nitrate impaired areas were the Maumee River (the systems for the communities of Defiance, Napoleon, McClure, Wauseon, Bowling Green and the Campbell Soup system) and a portion of the Sandusky River (Fremont). Some areas were identified for a watch list; most were located in the northwestern and central parts of the state. It is difficult and expensive to remove nitrate from drinking water; some systems are conducting nitrate removal pilot studies, but no Ohio surface water systems currently use treatment specific for nitrate removal. Ohio public water systems rely on blending the surface water with other sources such as ground water, selective pumping from the stream to avoid high nitrate levels by using off-stream storage in upground reservoirs or issue public notice advisories warning sensitive populations to avoid drinking the water while nitrate levels are high.
Pesticides could be evaluated for about 21 percent of the drinking water source waters. Five of 19 WAUs were identified as impaired, all in southwestern Ohio: one in Brown County (Mt. Orab); one in Miami County (Piqua); and the three sources used by the Village of Blanchester in Warren and Clinton counties. Eighteen areas were identified for a watch list because of elevated atrazine.
Since the end of the last report cycle, incidents of harmful algal blooms (HABs) impacting Ohio public drinking water supplies have greatly increased. Sufficient data were available to list 19 AUs (15 percent) as impaired. The impairment listing includes the entire Lake Erie Western Basin shoreline, Lake Erie Central Basin shoreline and Lake Erie Island shoreline AUs. In addition, 15 WAUs are now assessed as impaired. These include water supply sources in Lima (Allen County); Bowling Green (Wood County); Clyde (Sandusky County); Norwalk (Huron County), Akron and Barberton (Summit County); Woodsfield (Monroe County); Cadiz (Harrison County); Celina (Mercer County); the Wyanoka Regional Water District (Sardinia – Brown and Harrison Counties); and Clermont County. One large river AU was identified as impaired for algae: Maumee River Mainstem in Bowling Green (Wood County). Sixteen WAUs and three LRAUs are on the algae watchlist.