Determining the Levels and Sources of Mercury in Strawberry Creek Jeffrey Gregory Tudd Abstract Strawberry Creek begins in the Berkeley Hills flows through the UC Berkeley campus and discharges into the San Francisco Bay Historically some labs on campus impacted Strawberry Creek with mercury discharges Total mercury concentrations from sediments were determined at several sites along the creek The questions investigated in this study are 1 What are the levels of mercury in Strawberry Creek And if mercury is detected 2 What are the possible sources Concentrations were calculated at 11 sites using surface sediment samples which is where mercury tends to accumulate Sediment samples will be obtained because one of the primary controls of mercury concentration in sediment is grain size There is a strong correlation between an increase in mercury concentration and an increase in the amount of fine material The following equation calculates the sediment concentration normalized to percent fines ug g Hg norm Hg sed F63 Hg norm is the sediment concentration normalized to percent fines ug g Hg sed is the bulk sediment concentration ug g F63 is the percent fines 63um expressed as a fraction 0 F63 1 When mercury enters a creek it settles on the sediment Mercury prefers fine material in contrast to coarse material The results are expected to show that a significant increase in mercury may identify possible sources The California Regional Water Quality Control Board sediment target is 0 4 ug g Any results greater than 0 4 ug g will be investigated as a possible source Introduction Mercury can lead to severe poisonings which can be fatal when eating contaminated fish from waters with very low mercury levels Friberg Vostal 1997 Fish bioaccumulate mercury in the water Furthermore mercury is a neurotoxin that affects developing fetuses and young children CRWQCB 2000 Newborn babies of mothers exposed to methyl mercury during pregnancy by consumption of contaminated fish have higher mercury levels than their mothers Skerfving 1971 Prenatal poisoning occurs because methyl mercury passes the placental barrier Engleson and Herner 1952 The San Francisco Bay Regional Water Quality Control Board has listed all segments of San Francisco Bay as impaired due to mercury pollution Since it is an unacceptable health risk to humans and animals the removal of mercury is a high priority San Francisco Bay Regional Water Quality Control Board 1998 This is based on the exceedance of the numeric objective for mercury in water and the bioaccumulation of mercury in fish The numeric objective in water is 0 05 ug L and basically the same value as the criterion for consumption of organisms i e fish is 0 051 ug L EPA 2000 Because of the high levels of mercury in fish the Regional Water Quality Control Board RWQCB announced that fish from San Francisco Bay should not be eaten Strawberry Creek begins in the Berkeley Hills and drains into San Francisco Bay It is an urban creek that may be contaminated from stormwater runoff and direct discharge Charbonneau 1987 Mercury in stormwater runoff may be from anthropogenic air pollution that is deposited on the ground and washed into a creek during a storm event Mercury in direct discharge may be from labs or old machines that used mercury This study of mercury will help determine the levels of mercury in Strawberry Creek In addition any sources of mercury may be identified For example mercury in San Francisco Bay is mostly from the Gold Mines where hundreds of thousands of pounds of mercury were abandoned Hunerlach et al after the Gold Rush Mercury helped separate gold from the sediment After the Gold Rush the miners abandoned the mercury in sluices of the gold mines Presently in the South Bay most of mercury is coming from the New Almaden Mines in the Santa Cruz Mountains via the Guadalupe River CRWQCB 2000 Mercury was also abandoned in those mines and studies showed that mercury contaminated the Guadalupe River and the South Bay Previous research of mercury in Strawberry Creek only determined the concentrations of mercury however the sources of mercury were not addressed For example The Alameda Countywide Clean Water Program conducted sampling and analysis of embedded sediments from creeks i e Strawberry Creek and stormdrains throughout Alameda County during summer and fall of 2000 Alameda Countywide Clean Water Program Sept 2000 The objectives of their survey were to produce a synoptic survey of the distribution of mercury in creek and stormdrain sediments and to support coarse scale loads Alameda Countywide Clean Water Program July 2000 The Regional Water Quality Control Board has recently requested that stormwater programs evaluate mercury in their watersheds The project is called Joint Stormwater Agency Project to Study Urban Sources of Mercury The questions I will answer are What are the levels of mercury in Strawberry Creek Is the level safe for the public Where is the mercury coming from Is the College of Chemistry a possible source The study will address these questions in two ways First by taking water samples during a first flush event the amount of mercury from stormwater runoff is determined Second by taking sediment samples in Strawberry Creek possible sources of mercury will be discovered Different levels of mercury will determine possible sources For example if the headwaters of the creek have low levels of mercury and the samples taken below the College of Chemistry have significantly higher levels then this realization concludes that the College of Chemistry is a source of mercury Methods Water samples were taken in the North Fork Cross Campus Culvert and the South Fork Eucalyptus Grove Sediment samples were taken in the Strawberry Creek North Fork background Strawberry Creek South Fork background North Fork Eucalyptus Grove South Fork Eucalyptus Grove West Circle Cross Campus Culvert University House Birge Hall Big Inch Little Inch and Oxford Culvert The following table identifies the abbreviated locations and the map illustrates the campus sites Name Abbreviation Oxford Culvert OC North Fork Eucalyptus Grove NF EG West Circle NF WC Cross Campus Culvert NF CCC University House NF UH North Fork Background NF B South Fork Eucalyptus Grove SF EG Birge Hall SF BH Big Inch SF BI Little Inch SF LI South Fork Background SF B The samples obtained on the North and South Fork background allow me to evaluate whether mercury is originating on campus The North Fork
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