Pollution in Door County, Wisconsin

A marine safety technician responds to a reported oil sheen in the ship canal, July 30, 2013. Out of 193 spills of hazardous materials into county waterways from 1971–2015, 84% of them occurred in the Sturgeon Bay area. Most of the spills in the Sturgeon Bay area occurred at ship building and repair businesses.[1] Oil slicks may also come from passing freighters[2] or uncertain sources.[3]

Pollution in Door County, Wisconsin relates to the degree of pollution in the air, water, and land in Door County, Wisconsin. Pollution is defined as the addition of any substance (solid, liquid, or gas) or any form of energy (such as heat, sound, or radioactivity) to the environment at a faster rate than it can be dispersed, diluted, decomposed, recycled, or stored in some harmless form.[4]

Air

2016 HYSPLIT map

Most air pollution reaching the monitor at Newport State Park comes from outside the county. This map shows how the air travels to the pollution monitor in Newport State Park.[5] Because the monitor is near the shore, only the red lines (which show the lower air currents) meaningfully depict the path of ozone to the monitor. As shown on the map, these lower currents carry polluted air from major urban areas. But further inland, the air from higher up mixes more, so all color lines are significant when tracing the path of air pollution further inland. These higher currents (shown in green and blue) blow in from cleaner, mostly rural areas.[6]

Nitrous oxide concentrations measured by airplane over county waters are not significantly different than those measured closer to the Chicago area.[7]

In 2020, a traffic counter near the Bay View Bridge recorded an average of 12,500 daily vehicles.[8] Pollution modeling predicts the presence of locally generated air pollution associated with vehicular traffic in the city of Sturgeon Bay.[9]

In 2022, the Environmental Protection Agency decided that the northern part of the county met its standard for ozone.[10]

Wells, soils, and surface waters

19th century

Water-borne diseases were historically significant in the county. The Belgian migration to the county largely ceased after word of the 1856 cholera epidemic in Door County reached Europe. From 1859 to 1880, more than ten percent of all recorded deaths in the county were caused by dysentery or diarrhea. Death from dysentery or diarrhea was more common in the summer due food and water contamination.[11]

Aquifers and springs background

Aquifers

Door County has three types of aquifers. The newest is in a relatively shallow layer of sand and gravel, but tends to not to provide enough water except in the southeastern part of the county. Further down are layers of dolomite bedrock that are recharged by water percolating from the layer of sand and gravel. Past the dolomite is a layer of shale that typically does not contain water, although potentially it is a source of oil. Past the shale is a layer of sandstone that is also host to a bedrock aquifer. Only a few wells tap this deepest and oldest aquifer.[12] Due to the tilt of the layers and erosion, there are areas of the county missing certain layers. A study of three city wells serving Sturgeon Bay found that water from the surface fell anywhere from 13 to 115 feet per day from the surface down to the dolomite aquifer. When the snow melted in the spring, the water coming up from one well changed 9 days later to reflect the character of the new meltwater.[13]

Springs

Groundwater burbles up from the shallow aquifer through the fractured bedrock, forming fracture springs. It also may seep more slowly through the ground, forming seepage springs. Detailed measurements were taken of one fracture and three seepage springs during a 2014–2017 survey.[14] Although the fracture spring had large variations in output, it still had a greater flow rate than the other 409 springs surveyed. It had one of the highest specific conductance measurements (995 μS/cm) among the springs studied, due to the minerals dissolved in the water.[15] A study of wells, springs, and surface waters in six county wetlands took samples from September 2017 to June 2018. Enterococci were found in all of the surface waters and six of the eight springs, but not either of the two wells.[16] An earlier study comparing spring water and well water from five springs and 47 wells in Sevastopol found that spring water was more turbid than well water and more likely to be contaminated by coliform bacteria. Nitrates, chloride, and specific conductance were not significantly different between the springs and wells.[17]

Wells

A 1914 ad for bottled water placed in the Door County Democrat

The combination of shallow soils and fractured bedrock makes well water contamination more likely.[18] At any given time, at least one-third of private wells may contain bacteria, and in situations with quickly flowing underground water, wells may test clean one day but contaminated the next. Some household wells turn brown every spring from nearby manure applications.[18] Bacterial contamination of wells is more likely in the summer due to the larger human population. In wells that are contaminated, bacterial concentrations peak during the following rains in the late summer and early fall.[19]

Nearly all soil types in the county which have received a rating for their overall suitability for septic systems are considered to be "very limited" in their utility for septic systems. Out of 292 different combinations of soil associations and types in the county, 124 soil classifications are assigned a "very limited" rating, 4 are assigned a "somewhat limited" rating, and 164 have not been rated. The four which are "somewhat limited" are uncommon in the county.[20] Additionally, certain soil types are especially prone to leeching contaminants into the groundwater. Out of the 74 different total soil types present in the county, 44 types are known to be more susceptible to leaching contaminants into groundwater than typical soils. Out of the 44 more susceptible types, 22 are more susceptible to leaching when the water table is less than 12 inches from the surface, 10 are more susceptible to leaching when the soil is less than 20 inches above the bedrock, and 14 are regarded to be highly permeable soils. Some of the 44 more susceptible soil types have a combination of these characteristics.[21]

In 1968, 44 people on Washington Island were sickened with hepatitis, a food and water-borne disease, and one girl died.[22]

The porous and fractured dolomite bedrock was implicated as a factor in a June 2007 epidemic when 239 patrons and 18 employees[23] of the newly opened Log Den restaurant were sickened by a norovirus. Six were hospitalized. The virus was found to have traveled from a septic field 188 m (617 ft) away to the restaurant's well, contaminating their water.[24] From September to December 2007 a study was conducted in which dyes were placed into the septic system. The dyes traveled through the groundwater at about 2 miles per year, and researchers concluded that viral contaminants could travel "many miles in their life times."[25] For transient non-community public wells such as the one supplying the restaurant, state only regulated for contaminants within a 200-foot radius unless flow studies had previously been done. Modeling research supporting this decision predicted that pathogens would be unlikely to travel more than 155 feet per year.[26]

In September 2014, 16 people feel ill from drinking wellwater after rainwater washed manure went down a sinkhole in Jacksonport.[27]

Short-term rentals are thought to contaminate the groundwater whenever more people stay in a house or cottage than the septic system was designed to handle.[28]

Soils and groundwater

A 1919 ad touting the "maximum killing power" of a particular arsenate of lead pesticide. Also in 1919 it was found that arsenic residues remained on produce after washing. The pesticide began to be at least partially replaced by DDT beginning in 1946[29] and was later banned for use on food crops in 1988.[30]
An ad for sprayers placed in the Door County Advocate, 1904

The Wisconsin Department of Natural Resources reports 137 leaking underground storage tank sites, 385 spill locations, and 104 other areas involving contamination, such as of soils and groundwater, including 24 cases which polluted one or more neighboring properties and 82 open cases such as cherry orchards left with arsenic and lead-contaminated soils from pesticide use during the 1960s and earlier.[31] Additionally, two landowners voluntarily cooperated with the DNR, limiting their future liability.[32]

At the peak of fruit production in the 1940s–1950s there were about 12,000 acres of orchards,[33] about 3.9% of the 482 square miles of land in the county. Mines, prior landfills, and former orchard sites are considered impaired lands and specially marked on an electronic county map.[34] A different electronic map shows the locations of private wells polluted with lead, arsenic, copper, and other contaminants down to the section level.[35] A 2020 study sampling 237 private wells found one with a concentration higher than the federal standard. Certain areas appeared to have higher concentrations of arsenic than others.[36]

Creeks and Ahnapee River

A 2017 study looking at the impacts of nutrient pollution on microbes used DNA analysis to detect human pathogens in May Creek, Keyes Creek, and Sugar Creek during the months of May, September, and October. Aeromonas sobria was detected in May, September, and October, while Pseudomonas alcaligenes was only detected in September. Both species of bacteria are chemoheterotrophs which feed on organic material in the water.[37]

In 2016–2017, water was tested for pharmaceutical chemicals, with samples coming from May Creek, Keyes Creek, and Sugar Creek, and also from the Ahnapee River at the intersection with County Trunk H.[38] The tests found caffeine and acetaminophen in the Ahnapee River, and also the psychiatric drugs fluoxetine and carbamazepine and the antimicrobial triclocarban. Caffeine and carbamazepine were both found in May Creek. Caffeine was found in Keyes Creek and carbamazepine was found in Sugar Creek.[39]

In Green Bay

Further information: Fox River (Green Bay tributary) § Environmental issues

A counterclockwise circulation of water along the surface of Green Bay is thought to carry cleaner water south along the western shore of the bay, and nutrient-rich water from the Fox River north along the eastern shore of the bay. The circulation is thought to begin south of the mouth of the Oconto River on the west side. It changes direction at Pensaukee,[40] north of Long Tail Point and continues northward to Sturgeon Bay. The position of Long Tail Point marks the east-west division between the two masses of water.[41]

Turbidity

It appears that turbidity in Green Bay is higher than in the past, and that at least some of it is due to human impacts. The passage of large ships causes turbulence in the water to an extent comparable to dredging. Additionally, carp in the bay are known to uproot vegetation which could otherwise filter sediments suspended in the water.[42] When storms stir up water in the bay, microorganisms feed more rapidly on the nutrients. This temporarily depletes oxygen levels.[43]

Cormorant chicks with deformed beaks on Spider Island, 1988. Some chicks had beaks which beaks curved over each other, and others had upper and lower beaks that were different sizes from each other. The deformities are thought to be from PCBs bioaccumulating in the cormorants.[44]

Bioaccumulation

PCBs from Green Bay have been deposited into the county as windborne dust[45] and off of contaminated waters.[46] The state lists 6.85 miles of the Ahnapee River in Door County as an impaired waterway due to PCB pollution, a designation extending past the county line.[47]

Waterfowl footprints and dead alewives at Whitefish Dunes State Park in 2006. A 2004, study of 10 county beaches counted by far the most birds and bird droppings at Whitefish Dunes, yet it still had the third smallest mean E. coli concentration.[48]

Beach contamination

32 beaches are routinely monitored for water quality advisories.[49] Before the state beach monitoring program, an outbreak at Nicolet Beach in Peninsula State Park sickened 68 or 69 people in July 2002.[50] A two-year study of selected Door County beaches concluded that neither the abundance of bird droppings nor bird populations reliably predicted E. coli contamination,[a][51] although rainfall was associated with elevated E. coli levels in six out of eight beaches studied.[52] After a rain, E. coli counts may increase up to three times the normal amount and persist at a higher concentration for up to 12 hours. This could be due to increased stormwater drainage, including possible agricultural waste runoff.[53] From 2011–2015, a beach improvement program worked to reduce runoff.[54]

Mats of Cladophora algae provide homes for Salmonella bacteria.[55]

Agricultural nonpoint source pollution

In 2017, farmers spent $2,825,000 on agricultural chemicals,[56] in addition to $5,295,000 on fertilizer, lime, and soil conditioners;[57] as a result agricultural practices are a potential source of nonpoint-source pollution.

See also

Notes

  1. ^ Bird counts at 10 beaches in the summer of 2004 (first year of this study) found that Whitefish Dunes had the most birds, followed by Portage Park, Ellison Bay, Egg Harbor, and Bailey's Harbor. Random grid sampling of avian waste found that the beach at Whitefish Dunes had the greatest number of droppings, followed by Portage Park in second place and Bailey's Harbor in third, with Ellison Bay and Sister Bay tying as the beaches with the fourth most droppings. Meanwhile, the five beaches with the highest average E. coli concentrations were at Sunset Park, Otumba, Ellison Bay, Fish Creek, and Egg Harbor.[48]

References

  1. ^ Door County Hazard Mitigation Plan by the Door County Planning Department, June 28, 2016, Chapter 2: Risk Assessment, p. 43
  2. ^ Beach blackened by oil; Study ship departure link, Door County Advocate, Volume 107, Number 7, April 15, 1968, page 1
  3. ^ Demand action on oil mess, Door County Advocate, Volume 106, Number 23, June 8, 1967, page 1 (photographs: #1 and #2)
  4. ^ "Pollution - Definition from the Encyclopedia Britannica". britannica.com. 28 February 2018. Retrieved 5 March 2018.
  5. ^ Photo of the monitoring station on p. 128 of WI DNR. "Air Monitoring Network Plan 2016 June 2015" (PDF). EPA. Retrieved 6 February 2019.
  6. ^ U.S. EPA. "Wisconsin: Northern Milwaukee/Ozaukee Shoreline Area, Sheboygan County Area, Manitowoc County Area, Door County Area Final Area Designations for the 2015 Ozone National Ambient Air Quality Standards Technical Support Document (TSD)" (PDF). Green Book. Retrieved February 7, 2019.
  7. ^ Nitrogen dry deposition to Lake Superior and Lake Michigan by Theresa A. Foley and Eric A. Betterton, Journal of Great Lakes Research 45, 2019, page 230 (page 8 of the pdf)
  8. ^ WisDOT Traffic Counts, Wisconsin Department of Transportation, June 20, 1972
  9. ^ EJSCREEN, Environmental Protection Agency, accessed October 5, 2021
  10. ^ Air Plan Approval; Wisconsin; Redesignation of the Revised Door County (Partial) Area to Attainment of the 2015 Ozone Standard, federalregister.gov, April 29, 2022
  11. ^ Pioneer Cemeteries: Door County Wisconsin by John M. Kahlert, 1981, Baileys Harbor, Wisconsin: Meadow Lane Publishers, pages 3–5
  12. ^ Geology and ground water in Door County, Wisconsin, with emphasis on contamination potential in the Silurian dolomite by M.G. Sherrill Section: "Hydrologic Characteristics of Rock Units," 1978, U.S. Geological Survey Water-Supply Paper 2047, pp. 11–12
  13. ^ Field Verification of Capture Zones for Municipal Wells at Sturgeon Bay, Wisconsin by Kenneth R. Bradbury, Todd W. Rayne, and Maureen A. Muldoon, 2002, Open-File Report 2001-01, p. 3
  14. ^ Wisconsin Springs: Data, see the four points located in the county on the electronic map, Susan Swanson, Wisconsin Geological and Natural History Survey
  15. ^ An inventory of springs in Wisconsin by Susan K. Swanson, Grace E. Graham, and David J. Hart, Wisconsin Geological and Natural History Survey Bulletin 113, 2019, p. 8 (p. 14 of the pdf) and p. 13 (p. 19 of the pdf)
  16. ^ Water-quality indicators of human impacts to the wetlands of Door County, Wisconsin Technical Report by David Hart, Sarah Gatzke, Michael Grimm, and Nicole Van Helden, Wisconsin Geological and Natural History Survey Technical Report 006 2020, January 2021, Table 5: Water-quality indicators in sampled wetland springs, surface waters, and groundwater on pages 28-29, (pages 35-36 of the pdf), discussion on page 30 (page 37 of the pdf)
  17. ^ Hydrogeology and Groundwater Monitoring of Fractured Dolomite in the Upper Door Priority Watershed, Door County, Wisconsin by Bradbury, K.R., Muldoon, M.A., Wisconsin Geological & Natural History Survey # WOFR1992-02, January 1992
  18. ^ a b Protect the Water You Drink pamphlet, by Debbie Beyer, UW-Extension Basin Education Initiative; Shelby Giguere, and the Door County Soil and Water Conservation Department. See also Groundwater Quality Changes in a Karst Aquifer of Northeastern Wisconsin, USA: Reduction of Brown Water Incidence and Bacterial Contamination Resulting from Implementation of Regional Task Force Recommendations by Kevin Erb, Eric Ronk, Vikram Koundinya, and John Luczaj, published in Resources 2015, 4, 655–672; doi:10.3390/resources4030655
  19. ^ Geology and Ground Water in Door County, Wisconsin, with Emphasis on Contamination Potential in the Silurian Dolomite by M. G. Sherrill, Geological Survey Water-Supply Paper 2047, United States Government Printing Office, Washington, D.C., prepared in cooperation with the Wisconsin Department of Natural Resources, 1978, page 36 (page 42 of the pdf)
  20. ^ Web Soil Survey, "Area of Interest: Door County, Wisconsin; Soil Reports: Sewage Disposal, including minor soils" Natural Resources Conservation Service, United States Department of Agriculture, accessed September 29, 2021
  21. ^ Wisconsin Soil Classifications for Nutrient Management Planning - 2019 by the SnapPlus team directed by Laura Ward Good, University of Wisconsin-Madison, 2019
  22. ^ Environmental Geologic Aspects of Planning, Constructing, and Regulating Recreational Land Developments by Stephen M. Born and David A. Stephenson, published as an Inland Lake Renewal and Shoreland Management Demonstration Project Report funded by the Upper Great Lakes Regional Commission, January 1974, page 33
  23. ^ 2007 Annual Report: Door County Public Health Department by Rhonda Kolberg, page 57 (page 58 of the pdf)
  24. ^ Norovirus outbreak caused by a new septic system in a dolomite aquifer, by Mark A. Borchardt, Kenneth R. Bradbury, Elizabeth C. Alexander, Rhonda J Kolberg, S Catherine. P Alexander, John R. Archer, Laurel A Braatz, Brian M. Forest, Jeffrey Alan Green, Susan K. Spencer, published in Ground Water. 2011 Jan-Feb;49(1):85–97. doi: 10.1111/j.1745-6584.2010.00686.x.
  25. ^ Plum Bottom Closed Depression Groundwater Trace Final Report by E. Calvin Alexander, Jr., Jeffrey A. Green, and Scott C. Alexander 25 January 2008
  26. ^ Jay Y. Hodgson. (2002). Source Water Assessment Implementation Obstacles: Are Transient Noncommunity Wells Not As Important? Water Resources IMPACT, 4(2), page 18
  27. ^ Residents seek answers after Jacksonport manure spill, December 4, 2014, Door County Advocate
  28. ^ Short-term-rental Eyes on Sevastopol by Debra Fitzgerald, Peninsula Pulse, May 7, 2021
  29. ^ University of Wisconsin tests, Door County Advocate, January 11, 1946, page 13
  30. ^ Historical Use of Lead Arsenate and Survey of Soil Residues in Former Apple Orchards in Virginia by Therese Nowak Schooley, M.S. Thesis, Virginia Polytechnic, pages 9-11 (pages 16-18 of the pdf)
  31. ^ Door County Well Monitoring Program - Fall 2019 Summary by the UW Oshkosh Environmental Research and Innovation Center, December 9–10, 2019, p. 35 and RR Sites Map, Wisconsin DNR Remediation and Redevelopment; also see Cleanup Follows Evidence of Gasoline Leak by Craig Sterrett, Door County Pulse, January 5, 2022
  32. ^ Door County Comprehensive and Farmland Preservation Plan 2035: Volume II, Resource Report, Chapter 5: Economic Development p. 89 (p. 31 of the pdf)
  33. ^ Door County Land and Water Resource Management Plan 2021–2030 by Erin Hanson and Brian Forest, section on "Lead and Arsenic Contaminated Sites", page 112 (page 121 of the pdf)
  34. ^ Web-Map of Door County, Wisconsin ... For All Seasons!, Door County Land Information Office, Accessed September 7th, 2019
  35. ^ Groundwater Quality Viewer, UW-Stevens Point, College of Natural Resources, Groundwater Center
  36. ^ 2020 Door County Well Study Program: Final Report by Carmen Thiel and Gregory Kleinheinz, University of Wisconsin Oshkosh Environmental Research and Innovation Center, December 30, 2020, pages 10–11 of the pdf
  37. ^ Freshwater Sediment Microbial Communities Are Not Resilient to Disturbance From Agricultural Land Runoff by Rachelle E. Beattie, Aditya Bandla, Sanjay Swarup, and Krassimira R. Hristova, Frontiers in Microbioly, Volume 11, October 15, 2020; for the pathogen table see the supplementary material
  38. ^ Anthropogenic Drivers and Ecological Concepts of Antimicrobial Resistance by Rachelle E. Beattie, PhD thesis, Marquette University, August 2020. For the coordinates and site abbreviations, see page 156 (page 172 of the pdf)
  39. ^ Anthropogenic Drivers and Ecological Concepts of Antimicrobial Resistance by Rachelle E. Beattie, PhD thesis, Marquette University, August 2020. Chapter 8.1.6, Table S2-3, Continued and Tables S2-5 and S2-6, pages 159, 165–169 (pages 175, 181–185 of the pdf).
  40. ^ Lower Green Bay: An Evaluation Of Existing And Historical Conditions by Earl Epstein, Marc Bryans, Donald Mezei, and Dale Patterson for the Wisconsin Department Of Natural Resources, EPA-905/9-74-006 U.S. Environmental Protection Agency Region V Enforcement Division Great Lakes Initiative Contract Program, August 1974, section on "Mixing, Dispersal and Transport of Water in Green Bay", page 61
  41. ^ Lower Green Bay: An Evaluation Of Existing And Historical Conditions by Earl Epstein, Marc Bryans, Donald Mezei, and Dale Patterson for the Wisconsin Department Of Natural Resources, EPA-905/9-74-006 U.S. Environmental Protection Agency Region V Enforcement Division Great Lakes Initiative Contract Program, August 1974, "Summary" section, page 10
  42. ^ The Green Bay Watershed: Past/Present/Future by Gerard Bertrand, Jean Lang, and John Ross, Technical Report #229, University of Wisconsin Sea Grant College Program January 1976, page 106–107
  43. ^ Seiche- and storm-driven benthic oxygen uptake in a eutrophic freshwater bay determined with aquatic eddy covariance by Dirk Koopmans, Peter Berg, Shelby Brunner, and J. Val Klump, Freshwater Science, Volume 40, Number 2, May 11, 2021
  44. ^ Door to Nature: Bird Beaks by Charlotte Lukes, Peninsula Pulse, December 30, 2020
  45. ^ A Case Study of Atmospheric Dry Deposition by Jim J. Lin, Department of Life Sciences, National Air University, Tapeii, 1998
  46. ^ Sweet, Clyde W.; Murphy, Thomas J.; Bannasch, James H.; Kelsey, Cynthia A.; Hong, John (1993). "Atmospheric Deposition of PCBs into Green Bay". Journal of Great Lakes Research. 19 (1): 109–128. Bibcode:1993JGLR...19..109S. doi:10.1016/S0380-1330(93)71202-2.
  47. ^ Wisconsin Finds 240 More Impaired Waterways by Jackson Parr, Peninsula Pulse – November 22nd, 2017
  48. ^ a b Door County Avian Waste Survey by Colleen McDermott, UW-Oshkosh, co.door.wi.us, pp. 11 and 13, Archived December 7, 2015
  49. ^ Beach Reports, Wisconsin Department of Natural Resources; counties are located in the dropdown menu and Pilot Program Pitched for Faster Pollution Alerts, Door County Pulse, June 23, 2022
  50. ^ Detection of escherichia coli in northern Lake Michigan waters using QPCR method C by Roland Hernandez Jr, May 2018, M.S. thesis, UW-Oshkosh and Summer Time... and the Living is (Usually) Easy by Pat Miller, Whitefish Bay Association Newsletter, Summer 2003, page 1 (Archived August 10, 2003)
  51. ^ Evaluation of Avian Waste and Bird Counts as Predicators of Escherichia coli Contamination at Door County, Wisconsin Beaches by Gregory T. Kleinheinz, Colleen M. McDermott, and Vinni Chomeau, J. Great Lakes Res. 32:117–123 Internat. Assoc. Great Lakes Res., 2006
  52. ^ Impact of Rainfall on Escherichia Coli Concentrations at Beaches in Door County, Wisconsin, Amanda M. Griesbach, unpublished M.S thesis, University of Wisconsin-Oshkosh, 2013
  53. ^ Biological Indicators for Fecal Pollution Detection and Source Tracking: A Review by Enze Li, Faizan Saleem, Thomas A. Edge and Herb E. Schellhorn, Processes, Volume 9, Article 2058, November 17, 2021, page 6 (page 7 of the pdf)
  54. ^ Implementation of BMP's at Beaches to Improve Water Quality Archived 2020-06-22 at the Wayback Machine, Final Report, Door County Soil & Water Conservation Department, March 29, 2016
  55. ^ Seasonal stability of Cladophora-associated Salmonella in Lake Michigan watersheds Archived 2020-01-30 at the Wayback Machine by Muruleedhara N. Byappanahalli, Richard Sawdey, Satoshi Ishii, Dawn A. Shivelya, John A. Ferguson, Richard L. Whitman, and Michael J. Sadowsky, Water Research 43(2009), pp. 806–814
  56. ^ USDA NASS Quick Stats database results for chemical expenditures, 1997 through 2017
  57. ^ USDA NASS Quick Stats database results for fertilizer expenditures, 1997 through 2017
  58. ^ Case Summary: Sherwin-Williams Agrees to Clean Up Lead and Arsenic Contaminated Soil and Sediment at the Route 561 Dump Site New Jersey, Environmental Protection Agency, 2017

Strategi Solo vs Squad di Free Fire: Cara Menang Mudah!