Claiborne Parish Watershed District
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Claiborne Parish Watershed District |
Mercury (and Organic Toxins) in Fish
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FISH CONSUMPTION ADVISORIES IN NORTH LOUISIANA -- 7/15/02 http://www.deq.state.la.us/surveillance/mercury/fishadvi.htm; 1One meal is 1/2 pound of fish MERCURY*: Pregnant/breast-feeding women and children <7 years of age should consume no bass (all species) and in some areas no bowfish, and should limit consumption of all other species to Two Meals per Month. All other persons should limit bass to Two Meals per Month with no limit on other species.1 *Metals occur throughout fish; cannot be removed by cleaning Specific Mercury Advisories (see subsequent pages for details) have been issued for: Ouachita River LA/AR border to lock at Columbia (Morehouse, Ouachita, and Caldwell); Black Lake (Red River, Natchitoches); Bayou Bartholomew (Morehouse); Ivan Lake (Bossier); The Little River at Bodie's Landing (including Catahoula Lake)(Grant, LaSalle); Bayou De Loutre and Associated Lakes (Union); Toledo Bend Reservoir (Sabine, De Soto) ORGANIC SUBSTANCES*: *Build up, especially, in fish fat deposits and just under skin
Location Substance Advice
Wham Brake (Winn) Dioxin No fish consumption
Sibley Lake (Natchitoches) Priority organics No consumption of gar, shad, carp.
(PBCs) Skin and trim fat from other fish.
Broil, grill or bake fish. Do not fry
fish. Eat only one meal/week of
largemouth bass or crappie or one
meal/month of channel catfish,
striped bass.
Tensas River (Madison, DDT, Toxaphene Long-term fish consumption may
Tensas, Catahoula) cause health risk.
Bayou Lafourche:(Ouachita) Dioxin Limit consumption to Two Meals per
from Hwy. 80 overpass to I-20 Month for all species.
Which Fish Are Safe for Kids? By Kozak, D. and S. Harrar. Prevention, 2002, 54:1, p44, 1p, 1c - American Academy of Pediatrics recommends that parents limit the amount of fish children are eating. Eating seafood, particularly large, long-lived predator species at the apex of the food chain, such as king mackerel, shark or swordfish, is the primary way children are exposed to methylmercury. It can damage the developing brain and nervous system, kidneys, and immune system. Preparation and cooking techniques do not reduce the mercury content of fish because mercury binds tightly to protein in the muscle tissue. Recommended practices are: 1) Avoid shark, swordfish, king mackerel, and tilefish (especially pregnant women, nursing women, and children under 5). 2) Restrict to 2 oz, (1 meal per week): Walleye, pike, bass, muskie, and other freshwater fish. 3) Restrict to 12 oz, (2 or 3 meals per week) the top commercial fish--canned tuna, shrimp, pollock, salmon, cod, catfish, clams, flounder, halibut, sole, crabs, and scallops. These account for about 85% of the fish we eat and have mercury levels low enough that a few meals per week are safe. [http://map1.epa.gov/html/newsjuly02.htm] Eating Fish and Mercury in the Human Body Overview Mercury contamination of fish is a problem throughout the United States and other countries. Levels of mercury in fish sufficient to exceed the U.S. Food and Drug Administration (FDA) action level of 1 part per million (ppm) have been found from many water bodies, including some in Louisiana. Mercury accounts for 60 percent of all United States water bodies with an advisory of fish consumption, and mercury advisories for fish are found in 41 states. In August 1992, the Louisiana Department of Health and Hospitals (LDHH) and the Louisiana Department of Environmental Quality (LDEQ) issued Louisiana's first mercury in fish advisory. This advisory applies to a stretch of the Ouachita River from the Arkansas border to the lock and dam at Columbia, LA. As of July 2001, 19 separate advisories on 19 Louisiana water bodies have been issued as a result of mercury contamination of fish (below). Mercury as a Health Risk Louisianans' primary route of exposure to mercury in its harmful form is consumption of locally caught fish. Mercury at high levels in the body may cause learning problems and birth defects in children. Pregnant women can pass mercury from fish they eat to their unborn babies; nursing mothers can pass the mercury to their infants through breast milk. The nervous systems of unborn babies and children under 7-years old are still forming, so harm may be permanent. In all ages of people, high mercury levels in the body may cause tingling or numbness in the mouth, hands and feet, and vision and hearing troubles. Adults can stop eating mercury-contaminated fish, and in most cases their health problems will go away as their bodies slowly get rid of the mercury. Those who should be most careful when eating fish are:
Children under 7-years old,
Pregnant women,
Women who are planning pregnancies,
Women who are breast-feeding their babies, and
People who eat a lot of fish over a longtime from mercury advisory areas.
Persons who usually can safely eat fish which contain mercury are men, children over 7-years
old, and women who are not pregnant, are not planning pregnancies, and are not nursing babies.
Freshwater fish which are more likely to buildup mercury: Due to mercury build up, predatory fish at or near the top of aquatic food chains and larger, older fish tend to have the highest concentration of mercury. In one study, a mean mercury concentration of 0.002 ppb was associated with fish concentrations exceeding 0.45 ppm, a bioaccumulation factor of 225,000! Freshwater fish which are less likely to buildup mercury: How to Eat Fish Safely
Fish can be an important part of ones diet because it is a good source of protein. The fact that
mercury is found in fish from some Louisiana waters does not mean one has to quit eating fish.
There are no special cleaning or cooking methods that will take mercury out of fish, but there are
some things you can do to reduce your health risks:
Ask where the fish was caught, and call1-888-293-7020 to see if there is a fish advisory
for that body of water;
Follow the fish advisory directions about which fish to avoid or to eat less;
Eat younger and smaller fish, since they usually contain less mercury;
Get your fish from more than one place.
By diversifying your diet it is extremely unlikely that you will consume a sufficient number of
fish with high enough levels of contamination to cause harm.
What Does Maximum Allowable Level Mean? FDA uses a maximum allowable mercury level of 1.0 ppm in fish, a concentration 10 times lower than the lowest levels associated with the initial adverse effects of mercury. In the 1960's, when industrial discharges of mercury contaminated Japan's waters, average mercury concentrations in fish ranged from 9-24 ppm. The United States has had no cases similar to the Japanese episode. The Louisiana Departments of Health and Hospitals (LDHH) and Environmental Quality (LDEQ) jointly consider issuing advisories limiting fish consumption for pregnant or breast feeding women and children less than 7 years old for locations where the average concentration of mercury in fish exceeds 0.5 parts per million (ppm). Based on average concentrations exceeding 1.0 ppm and\or other types of information, the agencies advise limiting meals or no consumption for the most vulnerable population and limiting meals for the general population. What Are Mercury Levels in Louisiana Fish? Despite all the fish and seafood consumed in Louisiana, there have been no confirmed cases of mercury poisoning in the state. The highest average concentration found to date in Louisiana was 0.984 ppm for king mackerel collected south-southwest of Grand Isle. In 1992, the highest single sample concentration of 4.04 ppm was found in a largemouth bass from the Ouachita River. The Ouachita River contamination resulted in Louisiana's first mercury advisory for fish. In 1993, for the North Louisiana 12 Lakes Study, 15 largemouth bass from each lake were tested for mercury in fillets. Results (mercury in ppm): D'Arbonne Lake (0.74), Cheniere Brake (0.65), Cross Lake (0.52), Upper Toledo Bend (0.50), Wallace Lake (0.49), Lake Bistineau (0.49), Lake Bartholomew (0.31), Lake Claiborne (0.30), Caney Lake (0.30), Caddo Lake (0.30), Lake Bruin (0.10), Lake Providence (0.05). Resampling of lakes with average concentrations greater than 0.5 ppm failed to confirm high (1.0 ppm) levels of mercury, and no advisories were issued. From 1994-1997, LDEQ and USGS sampled approximately 33 new sites per year, and LDEQ has continued the effort. Targeted species include largemouth bass, channel catfish, blue catfish, crappie and bowfin, with substitutes: sunfish, freshwater drum, gar, striped bass, white bass, and buffalo. Composites consisting of at least three fish of the same species are collected for each sample, with generally five to 12 samples at each water body or sample site. Fortunately, despite this widespread testing and the application of even more protective fish consumption advisories than some other states, Louisiana currently has a limited number of advisories for mercury, and these advisories usually permit at least limited consumption of most fish by most people. How to Interpret an Advisory The presence of an advisory means that some precautions should be taken regarding the type of fish consumed or the segment of the population you are in. Details on each of these advisories can be found on LDEQ's fish consumption and swimming advisory web page, or by calling the LDHH hotline at 1-888-293-7020 or the LDEQ at (225) 765-0281. Fish consumption advisories related to mercury contamination in Louisiana water bodies [All Advisories as of June 2001 with dates when advisory was issued] Four were added 11/ 2000; one was added 7/2000, superseding two previous advisories for Toledo Bend Reservoir. (One meal is considered 1/2 pound of fish). Ouachita River LA/AR border to lock at Columbia, 102 miles 07/29/92, 8/94 -- Pregnant/breast-feeding women & children <7 years: no bass (all species); All other Species: Two Meals per Month. Others: Bass Two Meals per Month; no limit on other fish. Henderson Lake area including Lake Bigeux and all waters within the area bounded on the north by the St. Landry-St.Martin Parish Line, on the east by the West Atchafalaya River levee (Hwy. 3177), on the south by Hwy. 3177 and on the west by the West Atchafalaya Basin levee, 37.8 square miles -- 03/04/96 Pregnant/breast-feeding women and children <7 years: largemouth bass, crappie, and freshwater Drum One Meal per Month; No limit on other species; Others: No limit. Bayou Plaquemine Brule, Origin near Opelousas to the Mermentau River, 40 miles 10/96 Pregnant/breast-feeding women & children <7 years: no bowfin (choupique), and limit consumption of largemouth bass, crappie, or freshwater drum to One Meal per Month. Others: Bowfin Two Meals per Month, No limit on other species. Black Lake, 8 square miles 10/96 Pregnant/breast-feeding women & children <7 years: No bowfin (choupique),largemouth bass, white bass, or crappie One Meal per Month. Others: Bowfin to Two Meals per Month, No limit on other species. Bogue Chitto River, from the LA/MS state line to the Pearl River Navigation Canal, 35 miles 8/96 Pregnant/breast-feeding women& children <7 years: Bass (all species) or bowfin (choupique) One Meal per Month. Others: No limits. Pearl River (entire),57 miles -- 2/97 Pregnant/breast-feeding women & children <7 years: No bowfin (choupique), bass (all species), freshwater drum or bigmouth buffalo One Meal per Month. Others: NO BOWFIN, No limit on other species. Bayou Liberty, From origin near Slidell, LA to Lake Pontchartrain, 10 miles 2/97 Pregnant/breast-feeding women & children <7 years: Largemouth bass, white/black crappie, and freshwater drum One Meal per Month,1 Redear sunfish Two Meals per Month. Others: No limits. Chicot Lake 2.54 square miles --5/27/97 Pregnant/breast-feeding women & children <7 years: No bowfin(choupique), Largemouth bass. Others: Bowfin Two Meals per Month, No limit on other species. Seventh Ward Canal At Origin near Moulan Canal to the Intracoastal Waterway 11.5 miles 6/25/97 Pregnant/breast-feeding women & children <7 Years: One Meal per Month of these fish combined: bowfin (choupique), white crappie (sac-a-lait), flathead catfish and freshwater drum.1 There is no consumption limit on other species of fish.1 Others: No limits. Lake Vernon, 4,224 acres, 8/5/97, Pregnant/breast-feeding women & children <7 Years: Total of One Meal per Month of the following fish, combined: largemouth bass, flathead catfish, redear and bluegill sunfish (bream); No limit on other fish. Others: No limits. Gulf of Mexico off Louisiana Coast 9/4/97, For king mackerel 39 inches or less in total length: Pregnant/breast-feeding women & children <7 years: One Meal per Month.1 Others: Two Meals per Month. For king mackerel greater than 39 inches in total length: No consumption for all individuals. Bayou des Cannes, From origin near Ville Platte to the Mermentau River, 54 miles 10/9/97 Pregnant/breast-feeding women & children <7 years: One Meal per Month combined: bowfin (choupique), black crappie or freshwater drum (gaspergou). Others: No limits. Blind River, From origin to Lake Maurepas, 25 miles,-- 04/27/98 Pregnant/breast-feeding women & children <7 years: Bowfin (choupique) One Meal per Month. Others: No limits. Bayou Bartholomew, From the LA/Arkansas state line to the Ouachita River, 69 miles, 01/21/99; Pregnant/breast-feeding women & children <7 years: all fish Species One Meal per Month. Others: No limits.1 West Fork Calcasieu River, WestFork Calcasieu River from the junction of Hickory Creek and Beckwith Creek to the confluence with the Calcasieu River, 16.5 Miles 11/20/00 Pregnant/breast-feeding women & children <7 years should NOT consume largemouth bass, bowfin, or freshwater drum from the advisory area. Others: Two Meals per Month of bowfin, largemouth bass, and freshwater drum combined. Ivan Lake, 369 Acres, 11/20/00 Pregnant/breast-feeding women & children <7 years: NO Bowfin, One Meal per Month of largemouth bass. Others: Two Meals per Month of bowfin but do not have to limit consumption of other species. The Little River at Bodie's Landing (including Catahoula Lake), 58.25 miles Hwy 500 to Catahoula Lake, 18797.36 Acres- Catahoula Lake 11 miles- Little River from Catahoula Lake to weir near Archie Pregnant/breast-feeding women & children <7 years: No largemouth bass, freshwater drum, flathead catfish, or bowfin, Two Meal per Month of white crappie. Others: Two Meals per Month largemouth bass, freshwater drum, flathead catfish, and bowfin combined from the advisory area. Bayou De Loutre and Associated Lakes, From Hwy. 33 to the Ouachita River, including Phillips Lake, Hatley Lake, and Hudson Lake, 22.5 miles, 11/20/00 Pregnant/breast-feeding women & children <7 years: No species fish. Others: Two Meals per Month of any species of fish combined. The Toledo Bend Reservoir (7/19/2001, supersedes two previous advisories for this water body on Nov. 17, 1997),Toledo Bend Reservoir north of the Sabine River Authority Recreation Site 15 located at Pleasure Point Rd. The waters south of Recreation Sit 15 (including South Toledo Bend State Park) are not included in this advisory. Pregnant/breast-feeding women & children <7 years: No Bowfin, One Meal per Month of largemouth bass or freshwater drum. There are no limits on other species. Others: Two Meals per Month of bowfin. Where is the mercury coming from? Concentrations of mercury in our environment have increased significantly since the beginning of the industrial revolution. One study showed that on Minnesota and Wisconsin lakes, annual mercury deposition has increased almost fourfold since 1850. Similar deposition rates among widely scattered lakes indicates regional or global sources. The contamination of many ocean fish, such as tuna, swordfish and shark, and lake fish is due largely to mercury in coal burned by electrical power plants and mercury in thermometers, fluorescent and mercury vapor lights, and electrical switches. Mercury is released to the atmosphere as a gas by coal burning, trash incineration or direct volatilization. Once in the atmosphere, mercury can circulate for approximately one year and travel long distances from the sources. Similar to acid rain, the mercury is later deposited on the earth's surface. Paper mills, waste incinerators, and chloralkali plants are required to report to LDEQ mercury emissions. Yearly totals for the twenty-six facilities in LDEQ's Toxic Emission Data Inventory were 1,303 pounds in 1992 increasing to 2,518 in 1994 and decreasing to 1,947 in 1997. In 1997, only PPG Industries, Inc., a chloralkali plant (1228 pounds) and International Paper-Mansfield (240 pounds) emitted more than 100 pounds. In 1997, regionally, Stone Container in Jackson emitted 18 pounds and International Paper in Morehouse 91 pounds that year. EPA is studying electrical power plants, which currently are not required to report mercury and generally do not have any type of pollution abatement systems for mercury. Coal-fired power plants are the largest industrial source of mercury pollution, contributing 41 percent of all U.S. mercury emissions, and are the only unregulated industrial source of the pollutant. Final rules are due in March 2005. Summary It is unfortunate that mercury has become, over many years, too common in Louisiana's and the world's environment. However, even those water bodies currently under advisory in Louisiana are still capable of supporting sport fishing and fish consumption, provided some precautions are taken. By following the few simple rules outlined above families can continue to enjoying fishing, and eating what they catch, without causing any harm. Want to Know More? Call the Louisiana Dept. of Health and Hospitals (LDHH) hotline 1-888-293-7020, toll-free, for more facts about mercury in fish and to request a current list of mercury advisories issued for Louisiana waters. Call the Department of Environmental Quality (LDEQ) at (225) 765-0281 for Information about mercury in fish and about Louisiana's Mercury Monitoring Program (or fish sampling program). This information is available also on theWebsite at www.deq.state.la.us/owr. Website references for this article written by Alice Stewart, 9/20/04 (portions copied verbatim): http://www.deq.state.la.us/surveillance/mercury/2000report/intro.htm http://www.dhh.state.la.us/offices/publications/pubs-87/MERCURY1.PDF; http://www.deq.state.la.us/surveillance/mercury/mercsumm.htm (updated 3/30/2000) Addendum: EPA's ongoing four-year 'National Study of Chemical Residues in Lake Fish Tissue'studies 268 chemicals in fish from a representative sample of 500 U.S. lakes. Preliminary (first two years) results from predator and bottom-dwelling fish from 260 lakes: *All of the fish samples were contaminated with mercury. *Over half [Fifty-five percent(55%)] were contaminated at levels that exceed EPA's "safe" limit for mercury for women of average weight who eat fish twice a week (13 ppm). In 29 states, mercury levels in at least half of the fish samples exceeded this limit. *Three of every four [Seventy-six percent(76%)] of the fish samples exceeded the safe mercury limit for children of average weight under age three who fish twice a week (0.07 ppm); 63 percent of fish samples exceeded the limit for children ages three to five years; and 47 percent of the fish samples exceeded the limit for children six to eight years. *Eighty (80) percent of the predator fish samples contained mercury levels exceeding EPA's safe limit for women. In 18 states, 100 percent of the predator fish samples exceeded this limit. [Note: The study will be completed in 2006, so preliminary analyses must be viewed with caution.] *Louisiana lakes sampled (Average Mercury Concentration of Composite Sample in ppm): Webster Lake Bisteneau Largemouth Bass Predator -- 5 samples; Aver. Concentration: 0.74 ppm Webster Lake Bisteneau --Common Carp Bottom Dweller -- 2 samples; Aver. Concentration: 0.16 ppm Calcasieu Salt Lake Largemouth Bass Predator 5 0.56 St John The Baptist Lac Des Allemans Largemouth Bass Predator 5 0.15 St John The Baptist Lac Des Allemans Common Carp Bottom Dweller 5 0.15 Tensas Lake St. Joseph Black Crappie Predator 5 0.14 top WATERSHEDS OF WHICH CLAIBORNE IS A PART
U.S. WATER RESOURCES KIDS & EDUCATIONAL AIDS
Current Local Water Information top
Claiborne Parish Watershed District, P.O. Box 266,
Homer, LA 71040 Email: claibornewatershed@att.net topM? |
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